Method for producing rigid foams and products produced therefrom

In a method of producing a thermosetting foam, a first of two foam forming blends ("A Blend") is prepared using polymeric polymethylene polyphenylisocyanate ("PMDI"). A second of two foam forming blends ("B Blend") is prepared by mixing together a polyol; water; a tertiary amine catalyst having at least one ethyl (--CH.sub.2 --CH.sub.2 --) linkage between two heteroatoms, the heteroatoms being chosen from the group consisting of Nitrogen and Oxygen; and, an alkali metal organo-salt catalyst. A first blowing agent is included with one of the two foam forming blends. When the first and second foam forming blends are mixed together, the tertiary amine catalyst quickly initiates a reaction predominately of the polymeric polymethylene polyphenylisocyanate with water (as opposed to a reaction with the polyol). The quick reaction of the PMDI with water causes, prior to a gel point of the foam, both (1) the production of a second blowing agent for forming cells in the blends and for causing expansion in the liquid blends; and (2) sufficient exothermic heat to initiate boiling of the first blowing agent. Relatively large amounts of alkali metal organo-salt catalyst induce rapid vaporizing of the first blowing agent due to a high level of exothermic heat, whereby expansion of the mixed blends is substantially completed prior to the effective conversion of the mixed liquid blends to a solid. According to the method, a degree of completion of expansion of the foam at any point in time exceeds a degree of completion of chemical reactions of the foam. In another mode of the invention, a frothing agent is also employed.

BACKGROUND 
1. Field of Invention 
This invention pertains to methods of producing rigid foams and the foams 
made thereby, particularly polyurethane modified polyisocyanurate foams 
used for structural laminated board insulation. 
2. Prior Art and Other Considerations 
Cellular organic plastic foams made with urethane linkages, or made with a 
combination of both isocyanurate linkages and urethane linkages, are well 
known in the art. These foams have been made from the catalyzed reaction 
between polymeric polymethylene polyphenylisocyanate (a.k.a. Polymeric 
Methylene Di-Isocyanate, or "PMDI") and polyols of various physical and 
chemical properties. The PMDI has been used either alone, or in a blend 
with a blowing agent and (optionally) with a capped silicone surfactant. 
Such a blend utilizing PMDI has traditionally been called the "A-Blend". 
In order to form good cell size, good cell distribution, and good cell-wall 
construction, it has sometimes been preferred to add other "plastic foam 
cell modifiers" to the foam formulations. Often, it has been preferred to 
add these other agents to the polyol mixture. These foam cell modifiers 
include, but are not limited to: propylene carbonate, dispersing agents, 
organic surfactants, predominantly silicone surfactants, nucleating 
agents, fire retardants, and expansion agents. This blend including the 
polyol(s), expansion agent(s), and catalyst(s), has traditionally been 
called the "B-Blend". 
As used herein, the term "expansion agents" includes blowing agents and 
frothing agents. Moreover, as used herein, a blowing agent is a substance 
which is either produced, or becomes a gas, subsequent to the first of 
several chemical reactions. Many blowing agents have boiling points in the 
range from about 10.degree. C. to about 50.degree. C. On the other hand, 
CO.sub.2 is considered a blowing agent since, although it has a boiling 
point outside this range, it is produced by an isocyanate reaction. A 
frothing agent is a substance which is a liquid under sufficient pressure, 
then when released from pressure containment, accordingly produces 
gas-filled cells in foam prior to the initial chemical reaction. 
It has been considered important to keep the viscosity of each mixed blend 
about equal to the other blend. The rule of thumb has been to keep both 
the A-Blend and the B-Blend in the range of 250 cps to 1500 cps, and to 
run the chemical blends at about 60.degree. F. to about 70.degree. F. just 
prior to mixing. (All viscosities herein are "centipoise" taken on a 
Brookfield viscometer.) 
Prior art insulation thermosetting foams have been primarily "blown" or 
expanded by the use of CFC-11 (trichloromonofluoromethane). Some minor use 
of CFC-12 has also been used, as explained below. Due to environmental 
considerations, both CFC-11 and CFC-12 have fallen into disfavor. Most 
commercial foam producers have historically formulated all of their foam 
formulae around CFC-11 properties. These properties of CFC-11 affecting 
the foam formulae include the boiling point, the solubility parameters, 
the number of molecules per unit weight, the latent heat at boiling point, 
and the rate of membrane permeability, of CFC-11. The commercial foam 
laminate producer has learned to operate the continuous laminating foam 
board process based upon these known physical properties. 
There are two general phenomena which must take place in concert with each 
other in order to make quality structural foam laminates at a reasonable 
price. These two phenomena are (1) the expansion of the foam and (2) the 
foam chemical (polymerization and cross-linking) reactions. The expansion 
of the foam is measured volumetrically; the chemical reactions are 
measured in terms of solidification. As used herein, the "degree of 
completion of expansion" means the degree of completion (with reference to 
the ultimate potential expansion) of the foam expansion at any point in 
time. The "degree of completion of the chemical reactions", or comparable 
phraseology, means the degree of completion (with reference to the 
ultimate potential degree of polymerization and cross-linking) of the foam 
chemical reactions at any given point in time. 
It is critical that the chemical reactions have enough energy input to 
proceed to a substantially completed stage. This is especially crucial to 
foam board laminators who must depend upon a high degree of the 
trimerization reaction of three PMDI molecules to form the isocyanurate 
linkage. The most popular plastic foam insulation used for building 
construction is polyurethane modified polyisocyanurate foam. The only 
economical way this foam insulation can meet the stringent fire resistance 
requirements of building codes is to form high levels of isocyanurate 
group cross-linking. 
Likewise, it is important for the successful production of foam board 
lamination to have the degree of completion of the many complex chemical 
reactions of the thermosetting polymerization timed with the degree of 
completion of foam expansion. Additionally, these reactions must be 
finished quickly enough to obtain the full thickness and to maintain the 
planned thickness of a laminated board once it leaves a continuous 
double-belt laminator; at the desired density. 
When CFC-11 and CFC-12 are ultimately replaced by alternate blowing and/or 
frothing agents, the prior art techniques of creating energy input to 
effect the critical timing of expansion versus reactions will not suffice. 
Some new frothing and blowing agents have detrimental properties that 
interfere with exothermic heat energy. Moreover, these new agents demand 
more energy to function as expansion agents. Alternative blowing agents of 
this type include hydrochlorofluorocarbons, or partially hydrogenated 
chlorofluorocarbons, (referenced by the contraction "HCFCs"); as well as 
the non-chlorine containing fluorocarbons, called hydrofluorocarbons, or 
just "HFCs". All the physical properties mentioned above (including the 
boiling point, the solubility parameters, the number of molecules per unit 
weight, the latent heat at boiling point, and the rate of membrane 
permeability) differ for HCFCs and HFCs as opposed to CFC-11 and CFC-12. 
As will be shown, these physical properties are detrimental to both heat 
energy utilization and the timing of the reactions with the degree of 
completion of expansion. 
For example, both HCFC-123 and HCFC-141b have higher boiling points than 
CFC-11. The CFC-11 boils at 74.9.degree. F. (23.8.degree. C.); while 
HCFC-123 boils at 82.2.degree. F. (27.9.degree. C.), and HCFC-141b boils 
at 89.6.degree. F. (32.0.degree. C.). The higher boiling point means the 
start of the expansion of foam requires more heat energy input than prior 
art methods. Using prior art methods, these two new HCFCs naturally slow 
down foam expansion. Slow expansion of the foam allows the chemical 
reactions to create solidification prior to cell expansion, which causes a 
high foam density, i.e., low insulating properties. 
Another detrimental effect of some new expansion agents is the cooling 
effect caused by the partial evaporation of low boiling point products. 
For example, monochlorodifluoromethane, CHClF.sub.2, or HCFC-22, boils at 
-41.4.degree. F.(-40.8.degree. C.), meaning some of the product added will 
evaporate as soon as it is released to atmospheric pressure, and thus will 
cool the polymer mixture. Another new potential blowing agent in this 
category, CH.sub.3 CClF.sub.2, or HCFC-142b (monochlorodifluoroethane), 
has a boiling point of +14.4.degree. F., or -9.8.degree. C. 
It has been discovered that the cooling effect of an evaporating frothing 
agent reduces the exothermic heat generated by the urethane chemical 
reaction. To a large degree, the exothermic heat from the urethane 
reaction is the main heat energy source for the trimerization reaction. It 
is well known that high levels of heat energy are needed to complete the 
trimerization reaction which causes the PMDI to form into the isocyanurate 
linkage. A lack of trimerization causes product failures from the loss of 
dimensional stability and from excess flammability. 
U.S. Pat. No. 4,572,865 teaches the production of polyisocyanurate foams 
using CFC-12, dichlorodifluoromethane, CCl.sub.2 F.sub.2, which boils at 
-21.6.degree. F. (-29.8.degree. C.), as a frothing agent. While U.S. Pat. 
No. 4,572,865 does not specifically mention the cooling effect of using 
CFC-12, it is well known that this frothing agent does create evaporative 
cooling in rigid foam production. Other than possibly using high oven 
temperatures, U.S. Pat. No. 4,572,865 fails to teach any chemical reaction 
to make up the loss of exothermic heat energy which is taken away by the 
evaporative cooling of the frothing agent, CFC-12. 
As mentioned above, CFC-12 has fallen into disfavor. The only practical 
HCFC to replace CFC-12 as a frothing agent is HCFC-22, CHClF.sub.2, 
monochlorodifluoromethane. This compound boils at -41.4.degree. 
F.(-40.8.degree. C.), meaning it boils more easily and cools much faster 
than does CFC-12. Without a way to compensate for the loss of exothermic 
heat due to the cooling effect of evaporating HCFC-22, the trimerization 
reaction would be extremely difficult to effect, if not impossible. 
The strong solvent action characteristic of some of the new blowing agents 
is detrimental if used with methods of the prior art. To a large degree, 
these new agents are much stronger solvents in both B-Blends and A-Blends 
than were the CFC blowing agents of the prior art. The increased 
solubility causes dramatic decreases in blend viscosities. When the 
viscosity of the foamable blends gets too low, the resulting mixture of 
A-Blend (primarily PMDI) with B-Blend (primarily polyol) will form cells 
with thin walls and thick intercellular struts. This creates a foam which 
is poor insulation. Very small cell diameters (microcellular), with the 
cells having closed walls and thin struts, all at the proper density, are 
desired for good insulation properties. To create good cellular walls in 
the cellular foam matrix, the viscosity of the final foaming mixture must 
be high enough to restrain "drainage" from the cell wall into the cellular 
strut. Another need for higher viscosity polyols arises from the use of 
frothing agents. When a rapid frothing action occurs in a low viscosity 
liquid, the cell walls rupture creating an open celled foam. This is a 
common practice in producing flexible foam, as explained below. 
Thus it is seen that prior art methods of continuous lamination processing 
must be significantly changed to utilize HCFCs in order to be commercially 
successful. New methods are needed to compensate for the detrimental 
effect upon exothermic heat generation, and to maintain the timing that is 
needed in commercial foam production to balance the speed of expansion 
with the speed of chemical reactions. 
It is therefore an object of the present invention to provide an improved 
method for the production of a rigid thermosetting plastic foam 
insulation, which method provides an increased amount of exothermic heat. 
An advantage of the present invention is the provision of a method which 
overcomes the negative effects of evaporative cooling from low boiling 
point frothing agents. 
An advantage of the present invention is the provision of a method which 
not only overcomes the negative effects of evaporative cooling from low 
boiling point frothing agents, but also conveniently maintains the rate of 
expansion when utilizing higher boiling point blowing agents. 
It is another advantage of the present invention to provide a method 
whereby a frothing agent having a lower boiling point than used in prior 
art foams, as well as blowing agents with higher boiling points, can be 
used together and still maintain the temperatures needed for the 
completion of the trimerization reaction as well as maintaining the timing 
of the speed of foam expansion with the speed of chemical reactions. 
It is a further advantage of the present invention to provide an improved 
cell structure in rigid plastic foam insulation by utilizing smaller 
organic molecules in solution than previously used as a nucleating agent 
in the process. 
Yet a further advantage of the present invention is the provision of a 
method that compensates for the rapid expansion of a frothing agent by 
maintaining strong cell walls and a high percentage of closed foam cells. 
Yet another advantage of the present invention is the provision of a method 
that compensates for the strong solvent action of some new blowing agents 
and still maintains good cell wall formation. 
It is still another advantage of the present invention to provide an 
improved structural laminated foam board insulation at a cost lower than 
would be possible by using HCFC blowing agents alone, by utilizing at 
least some CO.sub.2 blowing agent. 
A further advantage of the present invention is the provision of an 
improved structural laminated foam board insulation at a cost lower than 
would be possible by using blowing agents plus utilizing at least some 
CO.sub.2 blowing agent by additionally utilizing a frothing agent. 
A further advantage of the present invention is the provision of a strong, 
economical, closed cell foam insulation which is characterized by a high 
degree of fire resistance and a high resistance to thermal conductivity. 
SUMMARY 
In a method of producing a thermosetting foam, a first of two foam forming 
blends ("A Blend") is prepared using polymeric polymethylene 
polyphenylisocyanate ("PMDI"). A second of two foam forming blends ("B 
Blend") is prepared by mixing together a polyol; water; a tertiary amine 
catalyst having at least one ethyl (--CH.sub.2 --CH.sub.2 --) linkage 
between two heteroatoms, the heteroatoms being chosen from the group 
consisting of Nitrogen and Oxygen; and, an alkali metal organo-salt 
catalyst. A first blowing agent is included with one of the two foam 
forming blends. 
When the first and second foam forming blends are mixed together, the 
tertiary amine catalyst quickly initiates a reaction predominately of the 
polymeric polymethylene polyphenylisocyanate with water (as opposed to a 
reaction with the polyol). The quick reaction of the PMDI with water 
causes, prior to a gel point of the foam, both (1) the production of a 
second blowing agent for forming cells in the blends and for causing 
expansion in the liquid blends; and (2) sufficient exothermic heat to 
initiate boiling of the first blowing agent. Relatively large amounts of 
alkali metal organo-salt catalyst induce rapid vaporizing of the first 
blowing agent due to a high level of exothermic heat, whereby expansion of 
the mixed blends is substantially completed prior to the effective 
conversion of the mixed liquid blends to a solid. 
The tertiary amine catalyst preferentially causes the water to react with 
isocyanate to produce CO.sub.2, thereby causing a degree of completion of 
expansion of the foam at any point in time to exceed a degree of 
completion of chemical reactions of the foam. The tertiary amine catalyst 
is chosen from a group consisting of dimethylethanolamine, 
pentamethyldiethylenetriamine, and bis(2-dimethylaminoethyl)ether. 
The organo-salt catalyst is chosen from a group consisting of potassium 
2-ethylhexanoate and potassium acetate. The amount of organo-salt catalyst 
mixed in the blend is greater than about 0.9 weight percent of the total 
weight of the foam. 
In one mode of the invention, a frothing agent is included in one of the 
foam forming blends. The high level of exothermic heat obtained by the 
present invention is sufficient to substantially complete all potential 
chemical reactions in spite of any cooling caused by any evaporation of 
the frothing agent. 
Thus, a higher exothermic temperature producing reaction is utilized than 
was used in prior art rigid foam production. The higher energy is utilized 
by the higher temperature requirements of higher boiling point HCFCs, and 
optionally, the increased heat energy is absorbed by evaporative cooling. 
The utilization of the higher heat energy avoids the scorching problems 
usually associated with excessive exotherm temperatures, but 
advantageously assures that the foam properties are not harmed by a lack 
of energy needed to complete reactions. This heat energy is utilized to 
assure the completion of the critical trimerization reaction, which in 
turn assures the flammability resistance and dimensional stability of the 
rigid polyurethane modified polyisocyanurate foam insulation. 
Additionally, the increased heat energy is used to advantage by the higher 
boiling point blowing agents utilized in the instant invention. These 
higher boiling points require more heat energy to cause expansion of the 
rigid foam. 
Also, certain B-Blend polyols are advantageously used to compensate for the 
higher solvent action of a new class of blowing agents described herein; 
as well as the rapid frothing action from a new class of frothing agents.

DETAILED DESCRIPTION OF THE DRAWINGS 
The method of the present invention is used to prepare foams which have 
isocyanurate linkages in them; i.e., no foams proposed herein have a 
chemical equivalent ratio of polyisocyanate to polyol of less than 
1.5:1.0. The typical polyurethane foams using the normal urethane 
equivalent ratio of isocyanate to polyol of 1.0:1.0; such as used in 
refrigerators, coolers, etc.; does not have the need for a high exothermic 
heat source to promote the trimerization reaction. The flammability codes 
of building construction foam insulation require the isocyanurate linkage. 
While not usually needed in refrigerator type polyurethanes, the 
polyisocyanurate foam of the present invention is often needed in other 
types of rigid insulation foam. Thus all foams of the present invention 
have an equivalent ratio, or "Index", of polyisocyanate to polyol in 
excess of 1.5:1.0, and most preferably in the range 2.0:1.0 to 5.0:1.0. 
In accordance with one mode of the invention, a first (i.e., "A-Blend") of 
two foam forming blends is prepared using at least polymeric polymethylene 
polyphenylisocyanate. A second (i.e., "B-Blend") of two foam forming 
blends is prepared by mixing together at least one polyol; a minor amount 
of water; a tertiary amine catalyst having at least one ethyl (--CH.sub.2 
--CH.sub.2 --) linkage between two heteroatoms (the heteroatoms being 
chosen from the group consisting of Nitrogen and Oxygen); and, an alkali 
metal organo-salt catalyst. The amount of alkali metal organo-salt 
catalyst mixed in the blend is greater than about 0.9 weight percent of 
the total weight of the resultant foam. 
A first blowing agent is included in at least one of the two foam forming 
blends. When the first and second foam forming blends (the A-Blend and the 
B-Blend, respectively) are mixed together, the tertiary amine quickly 
initiates a reaction of water with the polymeric polymethylene polyphenyl 
isocyanate but does not quickly initiate a reaction of polyol with the 
polymeric polymethylene polyphenylisocyanate. This water-PMDI reaction 
produces a second blowing agent (carbon dioxide, CO.sub.2) which forms 
cells in the blends and expands the blends prior to a Gel Point occurring 
in the urethane polymerization reaction. Moreover, the water-PMDI reaction 
initiated by the tertiary amine catalyst produces exothermic heat 
sufficient to initiate boiling of the first blowing agent. 
The method of the present invention produces CO.sub.2 for the purpose of 
foam expansion in such a manner that the degree of completion of expansion 
quickly moves ahead of the degree of completion of the chemical reactions. 
The degree of completion of expansion is greater than the degree of 
completion of the chemical reactions substantially throughout the foam 
production process. 
Inclusion of such a large amount of alkali metal organo-salt catalyst 
enables the mixture of blends to obtain an exothermic heat sufficient for 
further vaporizing the first blowing agent, including some relatively high 
boiling point blowing agents. The vaporization of the first blowing agent 
in turn forms further cells in the blends and further expands the blends 
whereby expansion of the mixed blends is substantially complete prior to 
completion of the polymerization and cross-linking reactions. 
As mentioned above, it is important to have the many complex chemical 
reactions timed with the foam expansion. The terms "Cream", "Gel", and 
"String" have been used to describe stages of the chemical reactions 
leading up to the formation of "Firm, Solid" isocyanurate foam. "Firm, 
Solid" foam occurs when there is about 90% or more completion of the three 
dimensional polymerization and cross-linking formation. Foam is said to be 
"Firm, Solid" where it is solid enough that it does not visibly move upon 
external application of a vibratory force. 
"Cream Time", usually contracted to "Cream", means the length of time (in 
seconds after mixing is started) that is required before any activity is 
noted in the liquid chemical mixture of A- and B-Blends. Usually, the 
first activity noticed is the expansion. However, when a frothing agent is 
utilized in a pressurized foam machine the essentially no delay before 
expansion begins. Nevertheless, at lower addition levels of frothing 
agent, the initialization of CO.sub.2 blowing expansion can be detected. 
The "Gel Point", or just "Gel", means the length of time that is required 
before the chemical reactions cause the material to show the first sign of 
losing pure liquid characteristics, and to show the first sign of 
semi-liquid properties. In actual practice, the expanding foam is sliced 
with the thin edge of a wooden, medical tongue depressor once every second 
to see if the slice immediate closes on itself (still liquid) or if the 
sliced plane remains separated (semi-solid). 
The "String Point", or "String", means the length of time required for the 
urethane polymerization and some isocyanurate cross-linking reactions to 
proceed far enough that the same wooden tongue depressor will "pull" a 
"string of material" from the surface of it. In actual practice, the flat 
side of the wooden depressor is placed against the expanding foam once 
every second, and quickly pulled away. The String Point is the point at 
which the material will stick to the wood, and will leave a trail of 
string(s) behind it as it is quickly pulled away. The foam is able to 
continue expanding beyond the String stage, but with increasing 
difficulty. It is advantageous to effect as much closed cell expansion as 
possible before the "Firm Solid" stage is reached. 
FIGS. 1, 2, 3, and 4 generally represent important relationships between 
the degree of completion of expansion and the degree of completion of 
chemical reactions such as polymerization and cross-linking. FIGS. 1-4 
show two dimensional graphs of curves which plot time on the "x" 
(horizontal) axis and either the "expansion" event or the "chemical 
reactions" event on the "y" (vertical) axis. Each of these concurrent 
"events" are, at any given point in time, in one stage or another of 
completion (from start to finish). The degree of completion has been 
depicted by the vertical axis shown in logarithmic increments from zero 
(0) stage of completion to 100% stage of completion. The degree of 
completion is defined as a point on the "y" ordinate. The actual "rate" is 
defined as the slope of the curve at any given point on the curve. These 
curves indicate that in the early stages (first 30 seconds) of either 
event, the "rate" of completion is quite rapid; i.e., the slope is steep. 
However, in the second 30 seconds, the slope becomes more gradual. Thus, 
for the second 30 seconds, in all examples of foam expansion and 
thermosetting chemical reaction of this invention, the rate decreases 
smoothly (or, "the event decelerates smoothly"). 
FIG. 1 depicts an expansion/chemical reactions relationship which is not 
acceptable because the chemical reaction degree of completion is so fast, 
or the expansion degree of completion so slow, or some of each, that a 
firm solid becomes formed before the expansion can reach its full 
potential. The conditions depicted by FIG. 1 create a foam density which 
is too high for good insulating properties. 
FIG. 2 depicts the normal prior art timing relationship whereby the degree 
of completion of expansion and the degree of completion of curing both 
proceed together. 
FIG. 3 represents an improvement of the present invention whereby the 
expansion degree of completion is ahead of the chemical reaction degree of 
completion. This method of producing CO.sub.2 expansion causes the degree 
of completion of expansion to quickly and permanently move ahead of the 
degree of completion of reactions. As long as the cell wall strength is 
maintained, this condition virtually assures that the closed cell foam 
reaches the maximum expansion potential available. 
The importance of FIG. 3 as compared to FIGS. 1 and 2 is that the 
"expansion" curve has an earlier starting time. In addition, at any given 
point on the completion ("y") axis, the degree of expansion completion is 
ahead (in seconds) of the degree of chemical reaction completion. 
FIG. 4 depicts the improvements noted in FIG. 3, with the additional 
improvement that the expansion degree of completion is enhanced with an 
additional permanent head-start over the chemical reaction degree of 
completion by the use of a frothing agent. 
The method depicted in FIG. 3 by which the degree of foam expansion is 
caused to proceed ahead, and stay ahead, of the degree of chemical 
reactions is characterized as follows: 
(1) The early foam expansion is created by quickly forming CO.sub.2 blowing 
agent without allowing many isocyanate groups to react with hydroxyl 
groups; 
(2) The smooth continuation of foam expansion by some vaporization of the 
blowing agent from the exothermic heat of the water-isocyanate reaction; 
(3) The continued expansion from boiling blowing agent from the exothermic 
heat of the chemical reactions being driven by a large amount of catalyst. 
The present invention requires the use of tertiary amine catalysts having a 
double-carbon (ethyl) linkage between two heteroatoms of Nitrogen and 
Oxygen. The processes of this invention rely upon the alkali metal 
organo-salt catalyst to initiate the urethane polymerization reaction. The 
alkali metal organo-salt catalyst offers more delay time prior to starting 
the urethane reaction than an ordinary urethane tertiary amine catalyst. 
By substantially covering the special tertiary amine catalyst molecules of 
this invention with water molecules via hydrogen bonding, their urethane 
reaction catalyzing power is hindered until the water molecules have been 
removed therefrom. The combination of a tertiary amine catalyst use is 
restricted to those having a carbon-carbon (ethyl) linkage between two 
heteroatoms and adequate water causes both an increase in the expansion 
degree of completion via CO.sub.2 production and an increase in the 
expansion via exothermic temperature. This method makes it virtually 
impossible for the chemical reactions degree of completion to overcome the 
expansion degree of completion. 
The foams of the present invention have at least one tertiary amine 
catalyst, which catalyst has at least one ethyl (--CH.sub.2 --CH.sub.2 --) 
linkage between a tertiary amine group and either an ether-oxygen (--O--) 
or another tertiary amine group. Both ether-oxygen and tertiary amine are 
strong hydrogen bonding sites. For purposes of definition, all the 
nitrogen atoms and the oxygen atom of these compounds shall be referred to 
herein as "Heteroatoms." As described in a paper by N. Malwitz, P. A. 
Manis, S.-W. Wong and K. C. Frisch, entitled "Amine Catalysis of 
Polyurethane Foams", given at the 30th ANNUAL POLYURETHANE CONFERENCE, 
Oct. 15-17, 1986, this class of tertiary amine catalysts has a 
preferential activity for the water-PMDI reaction. 
When such a catalyst is mixed with water in a B-Blend, the ethyl linkage 
between two heteroatoms is just the right length to assure that a water 
molecule will be advantageously fitted there; and will thus be the first 
reaction when final mixing with PMDI is effected. Ordinary catalysts with 
such linkages include, but are not limited to the following: 
dimethylethanolamine (DMEA), trimethylhydroxyethyldiamine, 
triethylenediamine (TEDA), Bis(2-Dimethylaminoethyl)ether, 
pentamethyldiethylenetriamine, and variations of this basic structure. 
The DMEA molecule and trimethylhydroxyethyldiamine have an active hydroxyl 
group, thus they react with PMDI, which has the effect of reducing 
catalyst level as well as increasing the need for more PMDI. The 
structural makeup of TEDA is such that water cannot bridge between both 
amine groups, thus it does not hydrogen bond well with water. Thus the 
most preferred catalysts from this group include: 
pentamethyldiethylenetriamine (Polycat-5) and 
bis(2-dimethylaminoethyl)ether (Dabco BL-19). 
Pentamethyldiethylenetriamine (Polycat-5) has the structure: 
EQU (CH.sub.3).sub.2 .dbd.N--CH.sub.2 --CH.sub.2 --N(CH.sub.3)--CH.sub.2 
--CH.sub.2 --N.dbd.(CH.sub.3).sub.2, 
EQU while the structure 
EQU (CH.sub.3).sub.2 .dbd.N--CH.sub.2 --CH.sub.2 --O--CH.sub.2 --CH.sub.2 
--N.dbd.(CH.sub.3).sub.2 
defines bis(2-dimethylaminoethyl)ether (Dabco BL-19). 
Thus it can be said that these substantially linear structures render the 
molecules very selective to hydrogen bonding with the water molecule. This 
assures that the water quickly reacts with the very active isocyanate 
functional group. These strong amines are able to initiate the reaction of 
isocyanate groups with the hydroxyl functional groups of the polyols; 
however, as long as they have water molecules attached to them by hydrogen 
bonding, the urethane reaction will be subordinated to the reaction 
between water and isocyanate. 
In prior art, Dabco BL-19 has been used by the flexible foam industry to 
catalyze the reaction of TDI (Toluene Di-Isocyanate) with water. The 
flexible foam manufacturers have used CO.sub.2 to blow this open celled 
foam for many years. The water-TDI reaction catalyzed by these selective 
catalysts can produce CO.sub.2 rapidly enough to cause cell wall rupture, 
which is desirable in flexible foam but not rigid insulating foam. Thus it 
can be seen that rapid expansion in any form can be harmful to the 
production of closed-cell rigid foam for insulation. 
The organo-salt catalyst of the present invention can be any form of alkali 
metallic cation linked with an organic anion. The preferred alkali 
metallic cation is potassium, however, the sodium cation is workable. The 
preferred potassium organo-salt catalysts used in the present invention 
are potassium 2-ethyl hexanoate (potassium octoate) and potassium acetate. 
Potassium acetate may be used if a faster chemical reactivity profile is 
desired than can be provided by potassium octoate. However, an advantage 
taught in the instant invention, is a method to delay chemical reactions 
while the expansion is proceeding. Furthermore, when utilizing the higher 
levels of potassium, the higher molecular weight form; e.g., potassium 
2-ethyl hexanoate (potassium octoate) provides a smoother chemical 
reaction profile than potassium acetate. Thus, potassium octoate is the 
preferred organo-salt catalyst of the present invention. 
Prepared potassium organo-salt catalysts are commercially available as 
Dabco K-15, Polycat 46, Hexchem 977, and PEL-CAT 9540A. A unique feature 
of the present invention is that the organo-salt catalysts are utilized in 
greater amounts than in prior art rigid foams. Whereas prior art 
formulations generally called for levels having been below about 0.9% on a 
total weight percent basis of the entire foam, the present invention uses 
levels above about 0.9% of total weight. On a "per hundred parts of 
polyol" basis, the minimum amount used in the scope of this invention is 
about 3.00 pphp. The increased amount insures that the exothermic 
reactions will proceed rapidly as well as reaching the highest 
temperatures possible. Thus, the invention utilizes the highest amounts of 
organo-potassium catalyst ever before utilized in connection with the 
preparation of rigid foam. Both the urethane reaction as well as the 
trimerization reaction must be well driven by the highest exothermic heat 
energy possible when utilizing either high boiling point blowing agents, 
or frothing agents which cool the chemicals, or utilizing both together. 
In some embodiments a blowing and catalyst package comprised of potassium 
hydroxide, water, and 2-ethyl hexanoic acid may suffice for the required 
water and organo-potassium catalyst portion of the B-Blend of the present 
invention. Both water (for CO.sub.2 blowing), and a potassium organo salt 
catalyst are required components of the present invention, and therefore 
may be added as a pre-blended mixture of water, potassium hydroxide, and a 
carboxylic acid. 
The blowing agents of the invention can be any material which is inert to 
the reactive chemicals and has a boiling point at one atmosphere of 
pressure in excess of about 10 degrees Celsius, up to about 50 degrees 
Celsius. The frothing agents can be any material which is inert to the 
reactive chemicals and has a boiling point at one atmosphere of pressure 
from about minus fifty degrees Celsius (-50.degree. C.) up to about plus 
ten degrees Celsius (+10.degree. C.). 
All foams of the present invention contain at least two expansion agents. 
One of the two expansion agents is always the blowing agent CO.sub.2. When 
the other expansion agent is a blowing agent, that other agent is chosen 
from the group consisting of ordinary hydrocarbons and other organic or 
inorganic compounds, CCl.sub.3 F, CF.sub.3 CHCl.sub.2, CH.sub.3 CCl.sub.2 
F, and those novel azeotropic blowing agent mixtures disclosed in U.S. 
patent application, Ser. No. 07/568707, filed Aug. 17, 1990 (which patent 
application is hereby incorporated herein by reference). These blowing 
agents include partially hydrogenated chlorofluorocarbons, sometimes 
called hydrochlorofluorocarbons, and are usually referenced by the 
contraction "HCFCs". They also include CFC-11 (CCl.sub.3 F). 
Some, but not all, foams of the instant invention contain a frothing agent 
in addition to a blowing agent. When used, the frothing agent is selected 
from the group consisting of CHClF.sub.2, CH.sub.3 CClF.sub.2, 
CHClFCF.sub.3, CF.sub.3 CH.sub.2 F, and CH.sub.3 CHF.sub.2, ordinary 
hydrocarbons, and other chemical compounds with boiling points between 
about -50.degree. C. and about +10.degree. C., which are inert to the 
reactive foam forming chemicals. This group includes some HCFCs, but it 
also includes non-chlorine containing hydrofluorocarbons, or just "HFCs". 
The preferred frothing agent is monochlorodifluoromethane, HCFC-22, with 
the formula CHClF.sub.2. 
When any higher boiling point blowing agents (e.g., HCFC-141b or HCFC-123, 
for example) are utilized in the processes of the present invention, a 
frothing agent need not be necessarily employed. The preferred HCFC 
blowing agent is HCFC-141b because, for one reason, it requires less 
weight percentage added than does CFC-11. This occurs because the amount 
of blowing potential is a function of the molecular weight of the 
compound. The lower the molecular weight, the more molecules there are per 
pound of material. Therefore, more blowing potential exists in lower 
molecular weight blowing agents. The prior art compound CFC-11 has a 
molecular weight of 137.4, while HCFC-141b has a 117.0 molecular weight. 
In planning to replace CFC-11 with HCFC-141b, the amount of HCFC-141b to 
use must be reduced to 85.15% (117/137.4) of the previous CFC-11 weight. 
A major advantage of using a low molecular weight frothing agent is 
likewise the reduction in amount needed. The frothing agent, HCFC-22, has 
a molecular weight of 86.5. When using HCFC-22 in place of CFC-11, the 
theoretical weight reduction would be 86.5/137.4, or about 63% of the 
CFC-11 needed. However, due to the rapid evaporation of HCFC-22, which 
causes the potentially harmful cooling effect, the rate actually needed is 
from about 75% to about 80% of the prior art CFC-11 addition rate. 
Some examples of frothing and blowing agents of the present invention 
include, but are not limited to, those shown in Table 1. 
TABLE 1 
______________________________________ 
B.P. 
Product Formula M.W. (.degree.F.) 
Name 
______________________________________ 
Frothing Agents 
HCFC-22 CHClF.sub.2 
86.5 -41.4 monochlorodifluoro- 
methane 
HCFC-142b 
CH.sub.3 CClF.sub.2 
100.5 +14.4 monochlorodifluoro- 
ethane 
HCFC-124 CHClFCF.sub.3 
136.5 +12.2 monochlorotetra- 
fluoroethane 
HFC-134a CF.sub.3 CH.sub.2 F 
102.0 -15.7 tetrafluoroethane 
HFC-152a CH.sub.3 CHF.sub.2 
66.0 -12.5 difluoroethane 
Blowing Agents 
HCFC-141b 
CCl.sub.2 FCH.sub.3 
117.0 +89.6 dichloromonofluoro- 
ethane 
HCFC-123 CF.sub.3 CHCl.sub.2 
152.9 +82.2 dichlorotrifluoro- 
ethane 
CFC-11 CCl.sub.3 F 
137.4 +74.9 trichloromono- 
fluoromethane 
______________________________________ 
As mentioned above, novel azeotropic blowing agents are disclosed in U.S. 
patent application, Ser. No. 07/568707, filed Aug. 17, 1990, incorporated 
herein by reference. Those novel azeotropic blowing agents, as well as the 
individual chemical compounds named in the azeotropes, are also suitable 
for use with the present invention. 
Any prior art polyester polyol may be used in the polyurethane modified 
polyisocyanurate rigid foam of this invention. Prior art polyols have been 
made quite miscible with CFC-11, which is a poorer solvent than the new 
HCFCs. The stronger solvent action of the HCFCs create a B-Blend with 
those polyols which has a very low viscosity. It may be too low for 
quality foam cell structure. This can be true even when using lower weight 
percentages of the HCFCs. The preferred polyester polyols used in 
connection with the present invention have a viscosity and solubility 
characteristics which produce blend viscosities between about 250 cps and 
about 1500 cps; and most preferably between about 450 cps and about 750 
cps at the temperature used in manufacturing. If the preferred range of 
viscosity cannot be achieved at normal blend temperatures, the 
temperatures are changed to accommodate the needed viscosity. The 
preferred polyols also have a hydroxyl number between about 150 and about 
300, and an average functionality between about 1.9 and about 3.0. 
As it turns out, when HCFC-141b is added at a rate of 85% of CFC-11 to 
almost any prior art polyol, the resulting viscosity of the polyol is 
lower than it was at 100% CFC-11. In fact, in certain polyols, even when 
reducing the HCFC-141b level another 25% below the 85% of CFC-11 level, 
the resulting viscosity can be lower than it was with 100% CFC-11. The 
reason the amount of HCFC is reduced an additional 25% is in order to make 
room for the CO.sub.2 blowing from the reaction of water and PMDI. 
It has been found advantageous when using higher boiling point HCFCs to 
maintain chemical temperatures higher than they were with CFC-11, which 
boils at room temperature. As mentioned earlier, HCFCs with prior art 
polyols will produce B-Blends with viscosities too low for good cell 
formation, especially if used at temperatures higher than 75.degree. F. It 
is necessary under all conditions to keep the blend viscosity in the 
optimum range. Therefore, a double dilemma is faced by the need to run 
high boiling point HCFCs at higher temperatures, plus the fact that the 
HCFCs create a B-Blend viscosity which is already too low. There are two 
ways to compensate: (1) The use of polyols which are less compatible with 
HCFCs, or are more viscous on their own, or are some of both; (2) The use 
of the frothing agent technique which produces a higher "apparent 
viscosity" due to the microcellularization of cells. However, the use of a 
frothing agent can likewise lead to cell wall rupture as described above. 
Fortunately, this problem may also be alleviated by the use of more 
viscous polyols. 
Polyols in this category are commercially available, but have not been used 
as the major component in the B-Blend for polyurethane modified 
polyisocyanurate foam. Some examples include, but are not limited to, 
Terate 203, Terate 253, and Terate 214 as sold by Cape Industries, 
Wilmington, N.C.; and Stepanpol PS-2402, Stepanpol PS-2002 as sold by 
Stepan Chemical Company, Northfield, Ill., and experimental Stepan Agent 
X-1507-xx. Processes of some modes of this invention specifically use the 
high boiling point HCFCs with higher viscosity polyester polyols, or less 
compatible polyester polyols, or those polyols being both, and use them at 
temperatures above the boiling point of CFC-11; e.g., above 75.degree. F.; 
and still maintain a suitable B-Blend viscosity. Likewise, processes of 
some modes of this invention specifically utilize polyols with unusually 
high viscosities with frothing agents in order to maintain better cell 
wall integrity. 
All B-Blends of the instant invention contain some water. The theoretical 
minimum amount of water required is defined as the minimum amount needed 
to provide one molecule of water for each double-carbon ethylene linkage 
available within the tertiary amine molecules. In real life, the amount of 
water needed is much higher than that. The amount to be included depends 
on the amount of CO.sub.2 to be produced. 
Say, for example, a minimum amount of gas volume replacement of 10% had 
been established. In order to produce enough CO.sub.2 to substitute for or 
replace about 10% (on a gas volume basis) of a conventional blowing agent 
(such as CFC-11) in a low density (sheathing) foam with a 2.1 "Index", 
about 0.50 pphp of water is included. (The contraction "1.0 pphp" means 
"one part per hundred polyol".) Depending on the Index and density of the 
foam, from about 0.5 to 2.5 pphp of water is included for about a 25% 
replacement. Over 3.0 pphp of water may be included for a higher Index 
foam using about 50% replacement. 
In order to effectively complete a trimerization reaction, it is essential 
to reach a exotherm temperature in excess of 250.degree. F., and 
preferably at least 275.degree. F. should be reached. Thus, all foams of 
the instant invention produce an exothermic temperature in excess of 
250.degree. F. as measured in a free-rise box-pour of at least 250 grams 
total weight. The mass of the sample, location of the thermocouple, and 
the ambient conditions have a large effect of the exothermic temperatures 
recorded. The cooling effect of a prior art foam utilizing CFC-12 as an 
evaporating frothing agent has been reported to have reduced the exotherm 
temperature to below 250.degree. F. 
When using HCFC-22 in the B-Blend, most polyester polyols hydrogen bond 
with HCFC-22. This hydrogen bonding keeps the vapor pressure of the 
B-Blend low. B-Blends using low levels of HCFC-22, generally below 15% by 
weight, have normal operating pressures. When using HCFC-22 in the 
A-Blend, only about 5% by weight can be added and maintain normal 
operating pressures. The use of high pressure mixing equipment is not 
necessary for blends, but must be used where the HCFC-22 is stored, 
weighed and added into the B-Blend. 
It is possible to add both HCFC-22 and a fluorocarbon blowing agent to the 
same blend. However, adding more fluorocarbon will tend to force the 
HCFC-22 out of solution. In utilizing other fluorinated products, they 
have the same effect as adding more HCFC-22 by taking up the hydrogen 
bonding sites on the organic compounds. Thus, the combination of HCFC-22 
and fluorocarbon blowing agent becomes the same maximum amount of pure 
HCFC-22 which is possible to add. 
In one embodiment of the present invention, the HCFC-22 frothing agent is 
added to the B-Blend, and HCFC-141b is added to the A-Blend. In another 
preferred embodiment, the HCFC-22 frothing agent is added to the A-Blend, 
and HCFC-141b is added to a more viscous, less compatible polyester 
polyol, such as Stepanpol 2402. In another preferred embodiment, both 
HCFC-22 and HCFC-141b are added to the B-Blend, which may use any 
polyester polyol taught herein, or taken from the prior art. 
RIGID FOAM PRODUCTS 
All foams of the present invention have physical properties well within the 
requirements of the Federal Specification HH-I-1972/GEN. Likewise, the 
thermal conductivity of some of the foams made with the HCFC-22 frothing 
agent and the HCFC-141b blowing agent appears to be about as good as the 
prior art foams made entirely with CFC-11. The intrinsic thermal 
resistance of HCFCs is not as good as the thermal resistance of CFC-11; 
however, the foam cell formation is greatly improved when frothing with 
HCFC-22. It is assumed that the smaller molecule, well distributed, has a 
nucleating effect which creates a very small, round, cell structure. This 
was referred to earlier as "microcellularization". 
The foams of the present invention are all foams which have isocyanurate 
linkages in them; i.e., all foams proposed herein have a chemical 
equivalent ratio of polyisocyanate to polyol in excess of about 1.5:1.0. 
The present invention is further illustrated by the following examples in 
which all parts and percentages are by weight unless otherwise indicated. 
Foam Example No. 1 
A high pressure impingement mixing machine was used for the foam examples. 
HCFC-22 was added in accordance with the apparatus shown in FIG. 5. FIG. 5 
shows that liquid HCFC-22 (also known as "R-22") was fed from a tank 18 to 
a downstream side of a large gear pump 20. The gear pump 20 was used to 
pump the B-blend. From the downstream side of the pump 20, the B-blend was 
pumped through a static mixer 21, through a heat exchanger 22, and (when 
ball valve 24 was closed) to a 250 gallon mixing tank 23. The outlet of 
tank 23 fed the intake of pump 20. When the ball valve 24 was opened, a 
back pressure valve 25 caused the mixture to be directed to the high 
pressure foam machines whereat the B-blend was mixed with the A-blend. The 
tank and heat exchanger were rated at 150 psig pressure, but the pressure 
gauges never exceeded about 80 psig, which is the normal operating 
pressure used to feed Bosch high pressure foam machine pumps. As the 
mixture blended well, and was cooled by the heat exchanger, the pressure 
dropped even as the amount of HCFC-22 in the blend was increased. The 
pressure at 14.1% HCFC-22, and at about 65.degree. F., was about 45 psig. 
Dry air pressure was added to the system to increase the pressure to 
insure that the high pressure Bosch pumps would not become "starved" for 
liquid material. 
The formulations and results of Foam Example No. 1 are provided below: 
______________________________________ 
Component Pbw Characteristics 
______________________________________ 
Stepanpol 2502 
100.00 Equivalent "Index" = 2.4 
Pluracol 975 
15.00 Free Rise Density = 1.64 PCF 
Surfactant 3.00 String at 70.degree. F. = 21 secs. 
Dabco K-15 7.50 1.5" Board Density = 1.8 PCF 
Polycat-5 0.25 Initial k-factor = 0.13 
Water 2.25 Laminator Temp. = 145.degree. F. 
HCFC-22 21.00 
TOTAL B-Blend 
149.00 
PMDI 273.50 
CFC-11 24.00 
DC-5098 1.00 
TOTAL A-Blend 
298.50 
______________________________________ 
Foam Example No. 2 
Using a typical laboratory high pressure foam machine, following the same 
blending procedure for HCFC-22 as taught in the production trial of 
Example 1, the following foam was made with the indicated results: 
______________________________________ 
Component Pbw Characteristics 
______________________________________ 
Stepanpol 2502 
100.00 Equivalent "Index" = 2.2 
P. E. Glycol 400 
10.00 Free Rise Density = 1.75 PCF 
Surfactant 3.00 String at 70.degree. F. = 19 secs. 
Dabco K-15 6.00 Closed Box Density = 2.09 PCF 
Polycat-5 0.20 Initial k-factor = 0.1187 
Water 1.43 Dimensional Stability Tests: 
HCFC-22 17.50 158.degree. F. & 97% RH, 24 Hours: 
TOTAL B-Blend 
138.13 % Volume Change = +0.723% 
PMDI 194.00 -40.degree. F., 24 Hours: 
CFC-11 16.10 % Volume Change = -0.419% 
DC-5098 1.00 
TOTAL A-Blend 
211.10 
______________________________________ 
Foam Example No. 3 
This example shows an early attempt at using HCHC-141b in place of CFC-11. 
The blowing efficiency was better than expected, thus the free rise 
density was too low. It used the same laboratory high pressure foam 
machine, and the same blending procedure for HCFC-22 as in Examples 1 and 
2: 
______________________________________ 
Component Pbw Characteristics 
______________________________________ 
Stepanpol 2502 
100.00 Equivalent "Index" = 2.2 
Pluracol 975 
10.00 Free Rise Density = 1.36 PCF 
Surfactant 3.00 String at 72.degree. F. = 23 secs. 
Dabco K-15 7.00 Closed Box Density = 
Polycat-5 0.30 Abandoned 
Water 2.21 Initial k-factor = 
HCFC-22 20.00 Abandoned due to low 
TOTAL B-Blend 
142.51 free rise density 
PMDI 240.00 
HCFC-141b 20.80 
DC-5098 1.00 
TOTAL A-Blend 
261.80 
______________________________________ 
Foam Example No. 4 
This example shows the first attempt to increase the density of the foam 
from Example 3. Both the blowing agents, CO.sub.2 and HCFC-141b, were 
reduced; as was the frothing agent. It used the same laboratory high 
pressure foam machine, and the same blending procedure for HCFC-22 as in 
prior examples: 
______________________________________ 
Component Pbw Characteristics 
______________________________________ 
Stepanpol 2502 
100.00 Equivalent "Index" = 2.2 
Pluracol 975 
10.00 Free Rise Density = 1.40 PCF 
Surfactant 2.50 String at 72.degree. F. = 22 secs. 
Dabco K-15 6.80 Closed Box Density = 1.60, 
Polycat-5 0.28 1.82 & 2.04 
Water 2.00 
HCFC-22 18.30 
TOTAL B-Blend 
139.88 
PMDI 231.00 
HCFC-141b 18.70 
DC-5098 1.00 
TOTAL A-Blend 
250.70 
______________________________________ 
Foam Example No. 5 
This example shows the frothing agent going into the A-Blend instead of 
B-Blend, with the HCFC-141b going into the B-Blend utilizing a polyester 
polyol which has poor miscibility with CFC-11, and is about 3 times more 
viscous than PS-2502. It used the same laboratory high pressure foam 
machine, and the same blending procedure for HCFC-22 as in prior examples: 
______________________________________ 
Component Pbw Characteristics 
______________________________________ 
Stepanpol 2502 
100.00 Equivalent "Index" = 2.4 
Surfactant 3.00 String at 77.degree. F. = 16 secs. 
Dabco K-15 7.00 Free Rise Density = 1.49 
Polycat-5 0.30 
Water 1.75 
HCFC-141b 22.00 
TOTAL B-Blend 
134.05 
PMDI 221.00 
HCFC-22 8.84 
DC-5098 1.00 
TOTAL A-Blend 
230.84 
______________________________________ 
Foam Examples Nos. 6A & 6B 
These examples show two non-CFC-11 production run foams, made without a 
frothing agent. The same production equipment used in Example 1 was used 
for this run. These foams had poor green strength, which caused expansion 
for several hours, followed by severe board shrinkage. This dimensional 
excursion was so serious in many of the laminated boards that it caused 
the facer to tear loose. Also this foam has a coarse cell structure, 
giving it a marginal R-Value. While some of the better samples of these 
laminated foam boards eventually cured and demonstrated a respectable 
dimensional stability, their short-term lack of green strength makes this 
example commercially undesirable. The main trial runs were made with 100% 
HCFC-123 or 100% HCFC-141b as follows: 
______________________________________ 
Component 6A 6B 
______________________________________ 
Polyester Polyol 100.00 100.00 
Silicone Surfactant 
3.00 3.00 
Potassium Octoate 3.11 2.76 
Amine Catalyst 1.12 0.91 
HCFC-123 53.00 -- 
HCFC-141b -- 43.00 
Total: 160.23 149.67 
PMDI 188.00 185.00 
Total: 348.23 334.67 
Index; 3.0 3.0 
Cream, Seconds: 15" 17" 
Gel, Seconds: 19" 24" 
String, Seconds: 25" 34" 
Tack Free, Seconds: 
44" 45" 
100% Rise, Seconds: 
98" 98" 
Initial k: 0.13 0.14 
______________________________________ 
Foam Examples Nos. 7A, 7B, & 7C 
These examples show some production run foams, made on the production 
equipment of Example 1 and Example 6. The foams of Examples Nos. 7A, 7B, & 
7C utilized the higher exothermic heat taught in this invention for the 
implementation of excellent green strength, improved cell structure, 
better k-factors, and good dimensional stability developed within 24 hours 
of production. 
______________________________________ 
Component 7A 7B 7C 
______________________________________ 
Stepanpol PS-2402 
100.00 100.00 -- 
Terate D-214 -- -- 100.00 
Propylene Carbonate 
4.00 4.00 5.00 
Silicone Surfactant 
2.00 2.00 2.00 
Dabco K-15 4.60 3.10 3.30 
Polycat 5 0.51 0.15 0.18 
Water 3.31 0.54 0.59 
HCFC-141b 15.60 24.60 26.60 
Total B-Blend: 130.02 134.39 137.67 
PMDI 275.00 167.00 185.50 
HCFC-141b 5.50 6.26 6.96 
DC-5098 1.00 0.75 0.83 
Total A-Blend: 281.50 174.01 193.29 
Total Blends: 411.52 308.40 330.96 
Index: 2.4 2.4 2.4 
Cream, Secs: 17" 18" 18" 
Gel, Secs: 29" 26" 25" 
String, Secs: 37" 34" 31" 
Tack Free Secs: 48" 41" 42" 
Max. Rise Secs: 90" 96" 76" 
Free Rise Density: 
1.73 1.75 1.76 
Initial k: 0.130 0.127 0.133 
______________________________________ 
While the invention has been particularly shown and described with 
reference to the preferred embodiments thereof, it will be understood by 
those skilled in the art that various alterations in form and detail may 
be made therein without departing from the spirit and scope of the 
invention.