Compositions having improved compatibility of halohydrocarbon blowing agents such as trichlorofluoromethane and suitable for curing with polyisocyanates to give low smoke urethane isocyanate foams are described. The compositions include the transesterification products of the residue obtained from the manufacture of dimethyl terephthalate and ethylene glycol or a polyethylene glycol; the transesterification product of that residue and a higher alkylene glycol or higher polyalkylene glycol; and a polyether polyol having an average hydroxyl functionality of at least 4.

SUMMARY OF THE INVENTION 
This invention is directed to resinous polyhydroxy resin compositions, 
derived from the residue of dimethyl terephthalate or terephthalic acid 
production, which are compatible with halohydrocarbon blowing agents and 
which can be cured by reaction with organic polyisocyanates to give low 
smoke foams having good physical properties. The polyhydroxy derivatives 
of the aforementioned residues are commonly used in the preparation of 
polyisocyanurate-polyurethane foams by reaction with polyisocyanate in 
which halohydrocarbon blowing agents are used. Such foam compositions are 
described in U.S. Pat. Nos. 4,237,238 and 3,647,759 which are incorporated 
herein by reference. It is advantageous in producing such foams that the 
blowing agent and the polyhydroxy component be compatible without 
separation for extended periods prior to mixing with polyisocyanate. Known 
polyhydroxy residue derivatives exhibit poor compatibility with 
halohydrocarbon blowing agents which quickly separate from the polyhydroxy 
resin in two days or less. In accordance with this invention, polyhydroxy 
resin compositions are provided which are compatible with halohydrocarbon 
blowing agent for extended periods of over 3 days, even 60 days and 
longer, without separation of the halohydrocarbon. In addition, the foams 
produced from such compositions have other desirable physical properties. 
DETAILED DESCRIPTION OF THE INVENTION 
The compositions of this invention, curable by reaction with organic 
polyisocyanate to a polymer foam in which the predominant recurring 
polymer unit is isocyanurate, comprise 
I. a halogenated organic blowing agent; 
II. a polyester polyol mixture prepared by 
(a) transesterification, with a glycol of molecular weight from about 60 to 
about 400, of a residue remaining after dimethyl terephthalate and methyl 
p-toluate have been removed from the product of oxidation of p-xylene in 
the preparation of dimethyl terephthalate; or 
(b) esterification, with an alkylene oxide selected from the group 
consisting of ethylene oxide, propylene oxide, butylene oxide, and 
mixtures thereof, of a carboxyl functional residue resulting from the 
removal of terephthalic acid from the mixture obtained by the oxidation of 
p-xylene in the preparation of terephthalic acid; and 
III. a polyether polyol having an average hydroxyl functionality of at 
least 4 comprising the adduct of at least 4 moles of a C.sub.2 -C.sub.6 
alkylene oxide and an organic compound having at least 4 functional groups 
reactive with said alkylene oxide. 
The polyol mixture II contains both ethylene glycol or polyethylene glycol 
derivatives of the described residue and sufficient higher alkylene 
glycol, or higher polyalkylene glycol derivatives of the residue to render 
said composition compatible without separation of said halogenated organic 
blowing agent for at least 3 days and capable of use to prepare a foam 
with a Class I flame rating. Much longer stability to separation of 
blowing agents is desirable, for example at least 60 days. Stability for 
periods in excess of 120 days has been achieved. 
In another aspect of the invention compositions without the halogenated 
hydrocarbon blowing agent I, with or without added flame retardant, are 
contemplated. Analogous compositions with different polyester polyols, to 
which a blowing agent is added later are common in commerce. It is highly 
advantageous that the polyester polyol mixture be compatible with the 
blowing agent which may be introduced by a formulator for sale to a user 
or by the ultimate user who typically requires storage stability for at 
least several days before the polyhydroxy component is reacted with 
polyisocyanate. 
The "residue" from which the polyester polyol component II is prepared is 
described in more detail in U.S. Pat. Nos. 3,647,759 and 4,237,238. The 
residue is the product remaining after dimethyl terephthalate and methyl 
p-toluate have been removed from the product of oxidation of p-xylene in 
the preparation of dimethyl terephthalate. Alternatively, the residue can 
comprise the product remaining after the removal of terephthalic acid from 
the mixture obtained by the oxidation of p-xylene in the preparation of 
terephthalic acid. In the first case, the residue contains ester groups 
which are transesterified with a glycol such as ethylene glycol in order 
to prepare the polyester polyol. In the latter case, the residue contains 
carboxyl groups which can be esterified with an alkylene oxide such as 
ethylene oxide, propylene oxide or butylene oxide to prepare a similar 
polyester polyol mixture. It has been determined that the polyester 
polyol, derived by the transesterification of the residue with ethylene 
glycol, diethylene glycol or a higher polyethylene glycol, or by a 
esterification with of an acid residue ethylene oxide, does not have 
adequate compatibility with halohydrocarbon blowing agents which separate 
out in a short period of time, often in one day or less. In accordance 
with this invention, it has been determined that a mixture of polyester 
polyols derived from ethylene glycol, and from a higher glycol, for 
example, propylene glycol exhibit much better compatibility with 
halohydrocarbon and also exhibit other advantageous physical properties 
when used in the preparation of polyisocyanurate-polyurethane foams. 
The mixtures of ethylene glycol and higher glycol derivatives can be made 
by separately preparing the polyester polyol derived from ethylene glycol 
and the polyester polyol derived from the higher alkylene glycol, or a 
mixture of ethylene and higher alkylene glycol can be reacted with the 
residue. Likewise, the polyester polyols can be prepared by 
transesterification or by esterification of the appropriate residue with 
diethylene glycol, di(higher alkylene) glycol, polyethylene glycol, or 
poly(higher alkylene) glycol. 
Preferably, the polyester polyol component contains a stoichiometric excess 
of glycol or alkylene oxide component which serves as a reactive solvent 
or diluent for the polyester polyol. 
Another essential component of the compositions of this invention is a 
polyether polyol III having an average hydroxyl functionality of at least 
four which comprises the adduct of at least four moles of a C.sub.2 
-C.sub.6 alkylene oxide and an organic compound having at least four 
functional groups reactive with the alkylene oxide. The organic compound 
preferably contains hydroxyl groups as the functional groups. Suitable 
polyether polyols are obtained by reaction of alkylene oxides with 
sucrose, methylglucoside, pentaerythritol, sorbitol and mixtures thereof. 
It has been found advantageous to include polyether polyols derived from 
alkyl polyamines or aryl polyamines. Preferably, the amine-derived 
polyether polyol is only part of the polyether polyol mixture in which the 
predominant component is one derived from a polyhydroxy organic compound. 
Generally, the ratio of mixed polyester polyol component II to polyether 
polyol component III is 75:25 to 95:5. More preferably, the ratio is from 
85:15 to 95:5. The mixture of polyester polyols comprising component II 
generally comprises an ethylene glycol, diethylene glycol, polyethylene 
glycol or ethylene oxide derivative which contain from about 5 to 50 
weight percent of a corresponding polyester polyol derived from higher 
glycol or higher alkylene oxide. Preferably, the higher glycol or alkylene 
oxide is a propylene glycol or propylene oxide. 
Typically, the foam compositions of this invention contain flame retardant, 
preferably organic compounds containing both halogen and phosphorus. 
Tris(beta-chloropropyl) phosphate is particularly preferred. 
Halogenated organic blowing agents are well known in the art. Preferred 
blowing agents are trichlorofluoromethane and dichlorodifluoromethane. 
The ratio of isocyanate equivalents in the organic polyisocyanate and the 
total hydroxy equivalents in components II and III can vary widely but in 
general is in the range of 1.5:1 to 4.0:1 and preferably in the range of 
2.0:1 to 3.0:1. 
It has been found that the addition of non-ionic surfactant is often 
beneficial. Suitable surfactants are well known in the art. The non-ionic 
surfactant is not a necessary ingredient of the compositions of this 
invention and, when used, should be present in a maximum of about 2 weight 
percent to prevent loss of desirable foam properties. 
The compositions of this invention are particularly useful for the 
preparation of low smoke, rigid isocyanurate foams which are suitable for 
use in building applications. Many national and local building codes 
specify smoke values for rigid polyurethane, polyisocyanurate or hybrid 
foams of 450 maximum as measured by ASTM E-84. The specification relates 
to the foam as applied. This often means rigid foams must meet the smoke 
requirement when tested at 0.5, to 4.0 or more inch thicknesses. The 
difficulty in achieving low smoke values and acceptable physical 
properties along with halohydrocarbon blowing agent compatibility is 
recognized in the art. The compositions of this invention are capable of 
meeting all of these requirements. In particular, the compositions of this 
invention can be prepared into rigid foams of 2-4 inch thickness which are 
halohydrocarbon compatible for 60 days and longer and which have the 
necessary physical properties such as dimensional stability.

Representative foam compositions in accordance with this invention are 
described in the examples, which are illustrative and non-linking. All 
amounts are expressed in parts by weight unless otherwise stated. 
EXAMPLES 1-4 AND COMATIVE EXAMPLES A-D 
A mixture of 4,841 grams Terate 203, 1,050 grams of tris 
(beta-chloropropyl) phosphate, 96 grams DC 193, 96 grams TMR-2, 25 grams 
Polycat 8 and 2,450 grams trichloromonofluoromethane (R-11) was stirred 
thoroughly using a two blade, propeller stirrer powered by a 0.25 HP drill 
at 1,500 RPM. After replacing R-11 lost due to evaporation, 8,942 grams of 
polymethylene poly(phenyl isocyanate) were added followed by agitation as 
above for 55 seconds. The mixture was poured into a 
26".times.60".times.12" cardboard box and allowed to free rise. The 
mixture creamed at 22 seconds and was fully risen (approximately 16" 
height) and tack free in 160 seconds. 
The foam was allowed to stand at room temperature for two days after which 
it and a duplicate bun were cut to provide five slabs 
(4".times.24".times.60") needed for ASTM E-84 flame testing. 
The polyols, phosphate, surfactant, catalyst and R-11 blend described above 
was duplicated on a smaller scale and was allowed to stand at 
67.degree.-73.degree. F. for periodic evaluation for R-11 separation. The 
composition described above was designated Comparative Example A. In a 
similar manner compositions corresponding to Comparative Examples B-D, and 
Examples 1-4 in accordance with this invention, were prepared and 
evaluated. The results are set forth in the Table below. 
TABLE 
__________________________________________________________________________ 
Comp. 
Comp. 
Comp. Comp. 
EXAMPLE A B C 1 2 3 4 D 
__________________________________________________________________________ 
COMPONENT A 
Polymeric Isocyanate 51.09 
50.61 
51.11 
51.60 
52.12 
52.51 
53.26 
50.21 
COMPONENT B 
Polyester Polyol 
Type I, Terate 203 27.66 
26.98 
20.35 
18.39 
16.70 
17.46 
13.72 
19.97 
Type II, Res D 173 0.00 
0.00 
6.07 
6.13 
6.15 
6.26 
5.95 
0.00 
Polyether Polyol 0.00 
0.00 
0.00 
1.30 
2.49 
2.61 
4.82 
8.56 
Tris (beta-Chloropropyl) Phosphate 
6.00 
5.98 
6.07 
6.13 
6.15 
6.26 
5.95 
5.99 
Non-Ionic Surfactant 0.00 
1.48 
1.50 
1.52 
1.52 
0.00 
1.47 
0.00 
Silcone Surfactant 0.55 
0.42 
0.42 
0.41 
0.38 
0.40 
0.37 
0.57 
TMR-2 Catalyst 0.55 
0.42 
0.42 
0.41 
0.38 
0.40 
0.37 
0.57 
Polycat 8 Catalyst 0.14 
0.10 
0.10 
0.10 
0.10 
0.10 
0.10 
0.14 
Trichlorofluoromethane (R-11) 
14.00 
14.01 
14.00 
14.01 
14.01 
14.00 
14.00 
13.98 
Ratio Polyester/Polyether 
100/0 
100/0 
100/0 
95/5 
90/10 
90/10 
80/20 
70/30 
R-11 Compatability, Days 
&lt;1 &lt;1 &lt;2 &gt;130 
&gt;130 
&gt;137 
&gt;137 
&lt;1 
Flame Date, ASTM E-84, 4"Sample Thickness 
Flame Spread Index 20 20 ND 20 18 ND 20 20 
Smoke Development Index 
205 373 ND 296 392 ND 481 528 
__________________________________________________________________________ 
The several components used in the composition in the Table are 
specifically identified as follows. Polymeric Isocyanate is a 
polymethylene poly(phenyl isocyanate) with an average functionality of 
about 2.5 and an NCO content of 32 percent. 
Polyester polyol, Type I is Terate 203 commercially available from Hercules 
Inc. and is believed to be a product prepared by transesterification of 
the residue of a dimethyl terephthalate esterified oxidate reaction 
product with an excess of diethylene glycol, as described in U.S. Pat. No. 
3,647,759 and 4,237,238 which are incorporated herein by reference. 
Polyester Polyol, Type II is an experimental product obtained from Hercules 
Inc., identified as Res D 173 and is believed to be a transesterification 
product similar to, and prepared in a similar manner to, the Type I 
material described above except that the glycol used for 
transesterification includes a polypropylene glycol, probably dipropylene 
glycol and also in a stoichiometric excess. 
Polyether Polyol is a commercially available sucrose-amine based polyol 
having a hydroxyl number of 530 mgKOH/g (NIAX FAF 529-Union Carbide.) 
Non-Ionic Surfactant is p-C.sub.8 H.sub.17 O(CH.sub.2 CH.sub.2 O).sub.n H, 
in which n is 12 (average). 
Silicone Surfactant is a commercially available material supplied by Dow 
Corning Chemical as DC 193. TMR-2 Catalyst is an isocyanurate catalyst, 
commercially available from Air Products. Polycat 8 Catalyst is a urethane 
catalyst, commercially available from Abbott Chemical. 
Although the present invention has been described with preferred 
embodiments, it is to be understood that modifications and variations may 
be resorted to, without departing from the spirit and scope of this 
invention, as those skilled in the art will readily understand. Such 
variations and modifications are considered to be within the purview and 
scope of the following claims.