CA2211676A1 - Method of producing rigid foams and products produced therefrom - Google Patents

Abstract

A thermosetting plastic foam solid is obtained using a blowing agent comprised at least partially from depolymerization of dicyclopentadiene into essentially pure cyclopentane. This unique hydrocarbon is miscible in polyester polyols, where others, such as extracted cyclopentane, are not. In a blend of 15 parts of liquid flame retardant per hundred parts polyester polyol, the mixture is both stable and has a suitably low viscosity.

Description

W O 96125443 PCT~USg6/02063 METHOD OF PRODUCING RIGID FOAMS
AND PRODUCTS PRODUCED L~i~;~EFROM

This application is a continuation-in-part application of United States Patent Application Serial No.
08/389,955, filed February 17, 1995, which is incorporated herein by reference.

BAC~GRO~ND
1. Field o~ In~ention This invention pertains to methods of producing thermosetting plastic foams utilizing any suitable catalyst to create exothermic heat, which hea~ in turn causes the unique expansion agent of this invention to vaporize, thereby creating small cells and a low density thermoplastic foam, as well as foams produced by such methods. Examples of such foams include polyurethane foams, polyurethane modified polyisocyanurate foams, and condensation reaction foams such as the formaldehyde series of urea, melamine, and phenol used for thermal insulation.

2. Related Art and Other Considerations Cellular organic rigid thermosetting plastic foams used for thermal insulation are well known in the art. Such foams can be made with urethane linkages, or made with a combination of both isocyanurate linkages and urethane linkages, or they can be made via the well known condensation reactions of formaldehyde with phenol, urea, and melamine. All such plastic foams must utilize an expansion agent, often referred to as a ~blowing agent~.

W O 96/2S443 PC~rrUS96/02063 The prior art is replete with references to techniques of exp~n~'~g foam cells. For many years, the dominant blowing agent for all thermosetting foams was trichloromonofluoromethane (CFC-11). Other types of blowing agents have been proposed, such as the use of hydrocarbon mixtures, taught in U.S. Patent No. 3,558,531. In recent years, various foam expansion methods have been taught in such United States patents as the following (all of which are incorporated herein by reference):

3,993,609, 4,636,529, 4,898,893, 4,927,863, 4,981,876, 4,981,880, 4,g86,930, 4,996,242, 5,032,623, 5,070,113, 5,096,933, 5,114,986, 5,130,345, 5,166,182 5,182,309, 5,205,956, 5,213,707, 5,227,088, 5,234,967, 5,236,611, 5,248,433, 5,262,077, 5,277,834, 5,278,196, 5,283,003, 5,290,823, 5,296,516, 5,304,320, 5,314,926, 5,318,996, and 5,336,696.

The relatively recent hydrogenated chlorofluorocarbons (called "HCFCs") are considered to be environmentally friendly expansion agents, but still contain some chlorine, and therefore have an "Ozone Depletion Potential" ~called "ODP"). Because of the ODP, the HCFCs have been mandated for eventual phaseout.

Another known class of blowing agents is the non-chloronated, partially hydrogenated fluorocarbons (called "HF~s") which have the general formula: HXFyC~l where x, y, and z are integers. The HFC compounds being proposed for future blowing agents have two serious defects: (1) high intrinsic thermal conductivity properties (i.e., poor thermal insulation); and, (2) expense. In view of the fact that approximately ten percent by weight of rigid foam insulation are the compounds used as blowing agents, high cost combined with the poor insulating value render HFCs W 096/25443 PCT~US96~02063 less attractive candidates for blowing agents in commercial foam insulation.

Hydrocarbon blowing agents are also known, which class includes halogen-~ree and CO2-~ree blowing agents.
For example, United States Patent 5,182,309 to Hutzen teaches the use of iso- and normal-pentane in various emulsion mixtures. Another example of hydrocarbon blowing agents is taught by Volkert in United States Patent 5,096,933, pointing out the virtues of commercial cyclopentane distilled and extracted from natural gas wells.

However, the hydrocarbon blowing agents mentioned in connection with such prior art have inadequate miscibility with polyester polyols, commonly used in polyisocyanurate modified polyurethane foam. The use of these alkanes require a chemical surfactant to obtain a suitable mixture. An improvement in the problem of poor miscibility is taught in United States Patent 5,166,182 to Blanpied, whereby the use of azeotropes with polar organic solvents enhance the miscibility with polar polyester polyols. However, all of that work was done using cyclopentane extracted from natural gas.

Another problem with some of these alkanes is the poor insulating value. For example, the thermal conductivity of n-butane at 25~C is 16.3 mW/m*~K, and n-pentane at 25~C is 14.8 m~/m*~K.

. 30 None of the prior art patents known to Applicants discuss how the cyclopentane is obtained for the disclosed foaming process, nor is there any recognition that any certain mode of cyclopentane production may endow the cyclopentane with properties which are beneficial for a foaming operation.

W 096/25443 PCTrUS96/02063 Although some cyclopentane originates from petroleum, most cyclopentane originates from natural gas wells, and is extracted as the bottom layer of distillation in a refinery, allowing the lighter molecules to be transferred through the natural gas pipellne network.
Cyclopentane obtained by extraction contains impurities. In fact, cyclopentane sold as "Technical Grade" contains from 22~ to 30~ impurities.

Extracted cyclopentane ("EXTRCP") has at least five problems which heretofore virtually prohibited it from being considered a serious candidate as a commercial blowing agent for rigid foam insulation. The first problem is that its limited supply is considerably below the amount needed to meet the quantity demanded of a commercial compound. The second problem is that this inadequate supply contains at least twenty-two percent impurities in the form of hexane isomers and n-pentane, which impurities significantly reduce insulating value of foam made therefrom. The third problem is that extracted cyclopentane is not miscible with the common polyester polyols which are used with HCFCs, nor those that were used with CFC-11.

The fourth problem is that extracted cyclopentane does not reduce the viscosity of the polyester polyol foamable blend to a workable level, even when liquid fire retardants are utilized.

The fifth problem is that the foam produced with EXTRCP will not pass the ASTM E-8~ maximum 75 Flame Spread Index even with moderate ~lame retardant.

W 096/25443 PCT~US96/02063 With respect to the third and fourth above-mentioned problems, the above-discussed United States Patent 5,096,933 to Volkert, while generally alluding to the use of polyester polyols, provides no specific example using polyester polyols. The lack of any specific example is consistent with the present inventors' understanding that mixtures made from polyester polyols and extracted cyclopentane are unstable mixtures. In this regard, extracted cyclopentane is no more suitable as a miscible blowing agent than n-pentane or iso-pentane. All three require chemical surfactants for miscibility.

Perhaps the largest obstacle to the use o~
hydrocarbon blowing agents in the United States is the fi~th problem -- flammability of thermoset plastics blown with hydrocarbon blowing agents. United States Patent 5,096,933 to Volkert mentions disadvantages caused by the flammability of the cycloalkanes. Volkert alludes to the optional use of flame retardants, but provides no example utilizing a flame retardant. Furthermore, none of the five Polyurethane Rigid Foam examples shown by Volkert would pass the m~; mllm Flame Spread Index (FSI) of 75 (ASTM E-84) required of construction foam in the United States. Likewise, a polyisocyanurate foam, without flame retardant, having an Isocyanate-to-Polyester Polyol INDEX of 2.3 badly failed the ASTM E-84 maximum Flame Spread Index requirement of 75, by achieving a 2174 FSI.

With regard to flammability, it is well known that organic surfactants contribute to the flammability o~ rigid plastic foam insulation. The three main classes of organic surfactants (anionic, cationic, and nonionic) all add to the flammability problem of plastic foam. However, the use of organic carbonates, such as ethylene carbonate and propylene carbonate, does not increase the flammability of plastic foam.

W O 96/25443 PCTrUS96/02063 TABLE I describes experiments attesting to the immiscibility o~ extracted cyclopentane with the polyester polyol having the most miscible potential with non-polar hydrocarbons, as well as the immiscibility of n-pentane and iso-pentane with this polyester polyol. The first column of TABLE I shows the weight ratio of polyester polyol to hydrocarbon blowing agent, with the proposed blowing agents n-pentane, iso-pentane, and extracted cyclopentane being shown in the second through fourth columns, respectively.
In all experiments, the polyester polyol utilized was Stepanpol PS-2502A, which (along with Cape's 245-C) is known to have the best miscibility with non-polar hydrocarbon blowing agents. In the experiments reflected by the first row of TABLE I, pure (no other chemicals) PS-2502A polyol was used at 80~ weight with 20~ by weight pentane; and so forth as indicated in the first column of TABLE I.
Significantly, all experiments showed the polyester polyol to be immiscible with extracted cyclopentane, just as it is with n-pentane and iso-pentane.
TABLE I
IMMISCIBILITY STUDIES
Weight Ratio N-Pentane Iso-Pentane Extracted (Polyol/Blow Cyclopentane ing Agent) 80/20 SeparatesSeparates Separates 75/25 SeparatesSeparates Separates 70/30 SeparatesSeparates Separates 50/50 SeparatesSeparates Separates 35/65 SeparatesSeparates Separates 20/80 SeparatesSeparates Separates W O 96125443 PCT~US9C,!ù'063 The ~ourth problem of extracted cyclopentane (EXTRCP) is shown in TABLE II below, where viscosity is high when blended in foamable blends.
________________________________________________________ TABLE II

CHEMICALS: Pbw Pbw Pbw Pbw Pbw Pbw Pbw Pbw Pbw Pbw PS-2502A 100100 100 loo lOo iO0 100 100 loo loO
Fyrol PCF ~ - --- --- --- 1515 15 15 15 Dabco K-15 4.04.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 PM-DETA 0.20.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 DC-5357 2.02.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Water --- --~ 1.8 1.8 1.8 1.8 1.8 Prop Carb --- 5.0 10 --- --- --- 5.0 10 --- ---Tex NP-95 --- --- --- 5.0 10 --- --- --- 5.0 10 EXTRCP 20.20. 20. 20. 20. 23. 23. 23. 23. 23.
Brook~ield Vic:c08ity ~ *
Cp~ at 65~F -6928 4016 2392 4480 2880 2725 BrokQ Broke 1810 1124 * = unstable emulsion separated (broke) rapidly T~3LE II shows that, without exception, every foamable blend made with extracted cyclopentane produced a Brookfield viscosity over 1000 cps at 65~F, even one with 10 parts by weight of a strong viscosity reducer, Texaco's NP-95. The foamable blends using both Fyrol PCF and Propylene Carbonate mixed into an unstable emulsion which soon separated. The inability to formulate with both liquid flame retardant and an organic carbonate is a serious obstacle to obtaining both flame resistance and a low enough viscosity to be workable In addition to obtaining cyclopentane by extraction, it appears that cyclopentane can also be synthesized from other hydrocarbons. In this regard, French W 096/25443 PCTrUS96/02063 Demande FR 2,595,092 and FR 2,595,093 teach the preparation of catalysts comprised of palladium with another transition metal such as ruthenium or rhodium for the cyclization and hydrogenation of 1,3-pentadiene, as well as the hydrogenation of cyclopentadiene, to cyclopentane. These French Demandes do not teach or suggest the synthesis of cyclopentane from dicyclopentadiene ("DCP"), or make any reference to foaming processes.

British Specifications GB 2,271,575A and GB
2,273,107A disclose two similar methods for synthesizing cyclopentane from dicyclopentadiene. Likewise, British Specification GB 1,302,481 teaches a method which synthesizes minor amounts of cyclopentane, but preferentially produces cyclopentene. While British Specifications GB 2,271,575A and GB 2,273,107A mention initially the search for blowing agents for polyurethane foam, neither provides an example of the use of cyclopentane as a blowing agent for foam, much less a foam produced with polyester polyol. In fact, European practice is to make polyurethane foam using polyether polyol rather than polyisocyanurate foam using polyester polyol.

Historically, considerable attention has been directed to the synthesis of cyclopentadiene and various isomers of the pentadiene and pentene building-block monomers. In this regard, dicyclopentadiene ("DCP"), C1oH12~ is the dimer of cyclopentadiene ("CP"), CsH6, and is the naturally stable form of CP. Cyclopentadiene monomer spontaneously dimerizes at room temperature. DCP is obtained ~rom the thermal cracking of high molecular weight hydrocarbons, such as naphtha and gas oils, particularly in the presence of steam.

W 096125443 PCT~US96~02063 Owing to its conjugated double bonds, CP can undergo numerous reactions, and has several important commercial uses. While most commercial CP is obtained from cracking DCP, CP is also obtained from other commercial reactions such as ethylene production. To prevent it from autodimerizing, CP must be cooled to below minus 20 degrees Celsius. To prevent spontaneous oxidation, CP must be protected from atmospheric oxygen. Thus, it is advantageous to convert DCP into c~clopentane in an enclosed reactor utilizing an excess o~ hydrogen, and adding cyclopentane as a diluent, as shown in GB 2,271,575A and GB 2,273,107A.

The thermocatalytic conversion of DCP to CP, and back again, and similar processes, have been well documented. However, such conversion and similar processes have not occurred in the context of utilization for a blowing agent for a rigid insulative foam which utilizes polyester polyol.

The similar processes mentioned above include use by Alder and Stein of palladium as a catalyst to polymerize and hydrogenate DCP into the trimer form, then to tetracyclopentadiene, and finally into pentacyclopentadiene.
Hydrogenation and polymerization to tetrahydrotricyclopentadiene has also been accomplished with Adams' platinum catalyst at room temperature and ~ifty pounds per s~uare inch pressure. Bai, Zhang, and Sachtler of the Center for Catalysis and Surface Science, Northwestern University, reported using palladium adducts in 1991 for cyclization and hydrogenolysis reactions of neopentane and other hydrocarbons. United States Patent 4,178,455 to Hirai et al. teaches that a transition metal catalyst, with a Lewis acid promoter, will convert urea, biurets, and allophanates into corresponding urethanes.

W O 96/25443 PC~rrUS96/02063 It is an object of the present invention to provide a thermosetting foam utilizing the advantages of specially synthesized cyclopentane ("SYNCP") as an improved insulating gas inside closed cells.

Another advantage of the present invention is the utilization of a hydrocarbon blowing agent which is readily miscible with common polyester polyols without requiring organic surfactants to make a stable blend.
An advantage of the present invention is the ability to create a foamable blend viscosity low enough to use in existing pumps without the requirement for additional viscosity reducing diluents.
Yet another advantage of the present invention is the utilization of an abundant source of specially synthetically produced cyclopentane, which insures that the costs will be contained in a reasonable range.
Still another advantage of the present invention is the achievement of a thermosetting ~oam having an ASTM
E-84 Flame Spread Index less than the maximum 75 allowed.

SU~ARY
A thermosetting plastic foam solid is obtained using a blowing agent comprised at least partially of the reaction product of the cracking of dicyclopentadiene into essentially pure cyclopentane. This unique cyclopentane hydrocarbon is miscible in polyester polyols, where others, such as extracted cyclopentane, are not. In a blend of 15 parts of liquid flame retardant per hundred parts polyester polyol, the mixture is both stable and has a suitably low viscosity.

CA 022ll676 l997-08-l4 W 096125443 PCTnUS96/~2063 DET~TT-~n DESCRIPTION OF T~E lNv~N-llON
It has been surprising to discover that cyclopentane synthesized ~rom dicyclopentadiene ("DCP"), C1oHl2/ is miscible with polyester polyols, not requiring additional surfactants or emulsifiers to mix well. As one skilled in the art will now appreciate upon comprehending this discovery, the miscibility o~ this unique cyclopentane creates a foamable blend having a viscosity low enough to utilize, whereas the ~XTRCP does not create this advantage.
The unique, or special, synthesized cyclopentane (SYNCP) utilized in all embodiments o~ this invention is obtained from Exxon Chemical Americas as imported "Exxsol Cyclopentane~. In this regard, the cyclopentane utilized in all e~bodiments o~ this invention is synthetically created by the depolymerization of DCP to CP. The synthetic cyclopentane used in the examples o~ this invention is in excess o~ 95~ pure cyclopentane.

The simpli~ied equation for synthesized cyclopentane (SYNCP) according to the present invention is as shown as EQUATION 1:

C H depolymerize 2C H catalyst+4H2 2C H
12--------------------- 5 6___________________ 5 lO

Examples o~ processes suitable ~or production o~
the synthesized cyclopentane (SYNCP) according to the present invention are described in GB 2,271,575A and GB
2,273,107A, both of which are incorporated herein by re~erence. In GB 2,271,575A , cyclopentane is used as a diluent, or carrier, during the depolymerization, e.g., "cracking", stage to reduce coking and the ~ormation o~
trimers, tetramers, and higher polymers which are not CA 022ll676 l997-08-l4 W 096t25443 PCTrUS96102063 readily decomposed to the monomer, as taught in GB
1,302,481, also incorporated herein by reference. In GB
2,273,107A, catalyst powder is circulated through reaction zones in a slurry form until it is removed by filtration.
This processing method allows the hydrogenation of the unsaturated monomer to cyclopentane at temperatures below 175~C. The advantages of this process are outlined in GB
1,115,145 and GB 1,264,255, both of which are incorporated herein by reference.

As another example of an implementation of EQUATION 1, the CsH6 represents the unsaturated five-carbon hydrocarbons, either linear or cyclic. Some pentadiene (CsH8) may also be present during the conversion. In such process, the cyclopentadiene is hydrogenated to cyclopentane, and the pentadiene may undergo hydrogenation and cyclization to cyclopentane using a catalyst, e.g., a transition metal (or adducts thereof) catalyst. An example of a palladium metal adduct is PdCl2.
The miscibility of the specially synthesized cyclopentane (SYNCP) of the invention is evidenced by TABLE
III.

Furthermore, the addition of a potassium catalyst, a tertiary amine catalyst, and the normal silicone type surfactant to the above blends of synthesized cyclopentane (SYNCP) produces clear solutions in the useful ranges of from about 13~ up to about 30~ cyclopentane by weight. By contrast, these same additives do not make clear solutions of any ratio blend with the three blowing agents of TABLE I.

PC'r~lJS96~02D63 ____________________________________________________________ TABLE III
MISCIBILITY STUDIES OF THE PRESENT CYCLOPENTANE INVENTION
Weight Ratio o~ Synthesized Polyol/Cyclopentane Cyclopentane 80/20 Stable Mixture 75/25 Stable Mixture 70/20 Stable Mixture 50/50 Stable Mixture 35/65 Stable Mixture 20/80 Stable Mixture In contrast to the high viscosities shown in T~3LE II utilizing extracted cyclopentane, as shown in TA}3LE IV foamable mixtures using the specially synthesized cyclopentane (SYNCP) of the invention have low viscosities. Furthermore, the mixtures o~ the invention were all clear solutions and remained stable.

It is well known that organic sur~actants contribute to plastic foam flammability, whereas propylene carbonate does not. Thus, the foam of Example 8 in TA~3LE IV utilizing 10 pphp propylene carbonate has a lower Flame Spread Index than the foam of Example 10 utilizing 10 pphp ethoxylated nonylphenol (Texaco NP-95). Advantageously, Example 8 also has a lower viscosity than Example 10, although both are low enough to use easily. Thus, the use of an organic carbonate in place of an organic surfactant is a major CA 022ll676 l997-08-l4 W 096/25443 PCTrUS96/02063 advantage not available to the extracted cyclopentane (EXTRCP), as evidenced by the broken emulsions in TABLE
II.
.
Thus it can be seen by comparing TABLE II
with TABLE IV, that the synthesized cyclopentane a~ords lower, workable viscosities even at the low temperature of 65~F.

Table V shows blends with, and without, liquid flame retardants (Fyrol PCF), with either extracted cyclopentane (EXTRCP) or synthetic cyclopentane (SYNCP), as well as their Brookfield viscosities at 77~F.

______________________________________________________ TABLE IV
FOA~BLE BLE ~ EX~MPLES 1 - 10 Ex 1 Ex 2 Ex 3 Ex 4 Ex 5 Ex 6 Ex 7 Ex 8 Ex 9 Ex lO
C~EMICALS: Pbw Pbw Pbw Pbw Pbw Pbw Pbw Pbw Pbw Pbw PS-A 100 lO0 100 100 100 100 100 100 100 100 Fyrol PCF --- --- --- --- --- 15 15 15 15 15 Dabco K-15 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 PM-DETA 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 DC-5357 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Water --- --- --- --- --- 1.8 1.8 1.8 1.8 1.8 Prop Carb --- 5.0 10 --- --- --- 5.0 10 --- ---Tex NP-95 --- --- --- 5.0 lO --- --- --- 5.0 10 SYNCP 20. 20. 20. 20. 20. 23. 23. 23. 23. 23.
Brook~ield Vi5c06ity Cp5 at 65~F 9 3416 2680 1248 3104 2200 2148 1344 874 1432 942 ______________________________________________________ CA 022ll676 l997-08-l4 W 096125443 PCT~S96~02063 ______________________________________________________ T ~ LE V
FO~M~RT-~ BLE~D EX~i~PLES 11 - 22 Exll Exi2 Ex13 Ex14 ExlS Ex16 Ex17 Ex18 Exl9 Ex20 Ex21 Ex22 CHEM}CALS: Pbw Pbw Pbw Pbw Pbw Pbw Pbw Pbw Pbw Pbw Pbw Pbw PS-2502A lOC 100 lO0 100 100 100 100 100 100 100 100 100 Fyrol PCF --- --- --- --- --- --- 15 15 15 15 15 15 D~bco ~-15 4.0 4.0 4.0 ~.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 PM-DETA 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0 Silicone 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 EXIRCP 21.7 --- 25.3 --- 29.1 --- 21.7 --- 25.3 --- 29.1 ---SYNCP --- 21.7 --- 25.3 --- 29.1 --- 21.7 --- 25.3 ---29.1 Brookfield Vi~co~ity cp~ ~t 77 F- 5320 3168 6072 3120 719Z 3160 2120 1408 2336 1440 3552 1680 One skilled in the art will notice a unique situation: with both versions of cyclopentane, as the amount of cyclopentane increases, so does the viscosity. This is in contrast to prior art blowing agents, which decrease viscosity with increased amount o~ blowing agent. Nevertheless, it is evident from TABLE V data that synthesized cyclopentane (SYNCP) not only produces lower viscosities than extracted cyclopentane (EXTRCP), the viscosities produced with about 15 parts by weight (per hundred polyol) liquid flame retardant added are low enough (below 1700 cps) to be easily used in any foam machinery. Conversely, without a liquid flame retardant being utilized, the ViSCQSities are over 3000 cps.

Vapor thermal conductivity properties o~ ~our blowing agents are shown below in TA~3LE VI, including one blowing agent ~rom the past (CFC-11), one blowing - agent from the present (HCFC-141b), a purported blowing agent of the future (n-pentane), and the SYNCP blowing agent of the present invention.

CA 022ll676 l997-08-l4 W O 96/254~3 PCTrUS96/02063 ______________________________________________________ , T~BLE VI
VAPOR Ir~M~r~ CO~ 11V1LY:

BLOWING AGENTmW/m~K at 25~C BTU in/hr*ft2~~F at 140~F
CFC-ll 7.80 0.0648 HCFC-141b 9.80 0.0960 n- Pentane14.80 0.1080 SYNCP 12.10 0.0864 ______________________________________________________ It should be noted that at higher temperatures (140~F), the SYNCP exhibits a better intrinsic insulation value than the currently utilized HCFC-141b. In general, TA~3LE VI shows the advantage of SYNCP over n-pentane as a potential future insulating gas.

TABLE VII shows thermosetting foam examples and illustrates the surprising differences between extracted (EXTRCP) and synthesized cyclopentane (SYNCP) of the present invention. Thus, TA~3LE VII demonstrates that when the extracted cyclopentane (EXTRCP) is compared directly to synthesized cyclopentane (SYNCP), the synthesized cyclopentane of the present invention shows unexpected and favorable results. All examples of the synthesized cyclopentane show better k-factors, and lower densities. All of the friabilities were lower than foam blown with prior art blowing agents.
At the higher 3.0 Index, and the highest water level (.85 parts per hundred parts polyol), the synthesized cyclopentane produced a foam with 24.5~ lower friability than the extracted cyclopentane counterpart.

CA 022ll676 l997-08-l4 WO 96/25443 PCT/US96~02063 T~l~MO~ LlrlG FOAM EXAMPLES 1 - 8 ~U.. 8UN Nl (pbw) Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 PS-2502A 100.0 100.0 100.0 100.0 100.0100.0 100.0 100.0 Potassium Cat. 2.7 2.7 3.0 3.0 3.2 3.2 4.0 4.0 T~rtiary Aminc 0.2 0.2 0.2 0.2 0.15 0.15 0.15 0.15 Silicone 2.2 2.2 2.1 2.1 2.1 2.12.0 2.0 Water --- --~ --- 0.68 0.68 0.85 0.85 EXTRCP --- 24.0 --- 26.9 --- 23.4 --- 26.7 SYNCP 24.0 --- Z6.9 --- 23.4 --- 25.7 ---TOTAL B-SIDE 129.1 129.1 132.2 132.2129.53 129.53 133.7 133.7 Lu~r. M70L 146.7 146.7 176.7 176.7170.3 170.3 208.9 208.9 Silicone 0.4 0.4 0.5 0.5 0.4 0.4 0.5 0.5 TOTAL A-SIDE 147.1 147.1 177.2 177.2170.7 170.7 209.4 209.4 TOTAL FOAM 276.2 276.2 309.4 309.4300.23 300.23 343.1 343.1 INDEX, NCO/OH 2.5 2.5 3.0 3 0 2.5 2.53.0 3.0 DENSITY, PCF 1.6 1.7 1.6 1.7 1.5 1.61.6 1.7 CREAM TIME 18" 19" 19" 20" 22" 23"21" 27"
GEL TIME 30" 30" 28" 29" 39" 42"42"' 43"
STRING TIME 44" 44" 43" 43" 48" 49"51" 52"
TAC}~ FREE 47" 46" 45" 46" 52" 53"53" 55"
FRIABILITY, ~ 2.57 2.39 2.94 2.61 3.60 2.967.88 10.43 Weight Lo~n INITIAL k 0.1401 0.1539 0.13970.1528 0.1377 0.1515 0.1397 .1508 Perc~nt B~tter 9.9% 9.4-s 10.0~ 8.0 R-Value with SYNCP

W096/25443 PCT~S96/02063 To further put the potential future insulating gases in perspective, several proposed HFC gases are added in T~3LE VIII to the pentane isomers and the prior art fluorocarbons, showing respective insulation data.
5 _ __ _____________________ TABLE VIII
VAPOR T~RM~T, CONVUISL1V1'LY:
BTU in/hr*ft2*~F mW/m~K
BLOWING
AGENT lat 140~F 2at 44~C 3at 20~C ~at 25~
CFC-11 0.0648 0.064 8.4 7.8 HCFC-141b 0.0960 0.084 9.7 ~.8 HFC-245ca ------ 0.092 13.3 ---HFC-245fa ------ 0.097 ---- ---HFC-356mf~m ------ 0.102 ---- ---HFC-365mfc ------ ----- 10.6 ---SYNCP 0.0864 ----- 12.0 12.1 n-pentane 0.1080 ----- ---- 14.8 ~ow Chemical Company.
Knopeck, Parker, Richard, Shankland, "Polyurethanes ~994, Page 116.
Murphy, J., & Costa, J., 'Polyurethanes 1994', Proceedings, Page 323.
BASF Chemical Company.
(Di~ferent data sources show slightly different conductivity values.) _______________________________________________________ By noting the lambda values in the third column of TABLE VIII, one can compare cyclopentane (SYNCP) to HFC-245ca and HFC-365mfc. Then, by using HFC-245ca to interpolate that data into the second column, one can see that SYNCP has a better intrinsic insulating value than three of the four HFCs listed.

In view of the foregoing, preferably the '~
foamable blend which contains most of the synthesized cyclopentane also utilizes a liquid fire retardant.
The most preferred embodiments of the instant invention also utilize (1) a lower boiling point alkane blowing W ~96125443 PCT/US96/02063 agent with the specially synthesized cyclopentane (SYNCP) to increase internal cell gas pressure as a protection against shrinkage and [optionally] (2) a polar organic blowing (e.g, expansion) agent which azeotropes with cyclopentane such as taught in United States Patent 5,166,182, or a viscosity depressant such as propylene carbonate or the non-ionic surfactants such as ethoxylated nonylphenol. The latter are especially use~ul i~ the ~oamable blend is to be cooled below 70~F prior to use.

Suitable ~lame retardants utilized in the invention include, but are not limited to, tri(2-chloroisopropyl)phosphate, tricresyl phosphate, tri(2-chloroethyl)phosphate, tri(2,2-dichloroisopropyl)phosphate, diethyl N,N-bis(2-hydroxyethyl) aminomethylphosphonate, dimethyl methylphosphonate, tri(2,3-dibromopropyl)phosphate, tri(l,3-dichloropropyl)phosphate, and tetra-kis-(2-chloroethyl)ethylene diphosphate.

The isocyanates utilized may be any organicisocyanate. However, the most preferred type is the polymeric polymethylene polyphenylisocyanate having an average functionality of between 2.0 and 3.5.

The polyester polyols pre~erred ~or this invention are those aromatic organic esters based upon one, or a combination, o~ the phthalate isomers linked together with mixed glycols, predominately diethylene glycol.

Any o~ the prior art catalysts and cell stabilizing surfactants may be utilized. However, the potassium-organo-salt catalysts are pre~erred.

W O 96/25443 PCTrUS96/02063 Thermosetting Foam Examples 9 through 15 in F
TA~3LE IX show the most preferred foam formulations.

In thermosetting Foam Examples 9 through 15, any HCFC or HFC may be substituted for, or mixed with, any of the additional expansion agents; e.g., propane, iso-butane, acetone, methyl/ethyl alcohol, or methyl acetate. One skilled in the art will recognize that other combinations of the components shown in TA~3LE IX
can be interchanged, or intermixed, or added at different levels, to provide a thermosetting foam with different properties.

Advantageously, the abundance of DCP makes it an ideal raw material for the synthesis of pure cyclopentane according to the present invention.

As an additional advantage, as understood with reference to the foregoing examples, the use of SYNCP faciliates the use of little or no organic surfactants for either compatability or viscosity reduction, so that the foamable blends of the present invention are substantially devoid of organic surfactants.
Thermosetting Foam Examples 16 and 17 (see TABLE X) show the use of polyether polyols in conjunction with polyester polyols. These foams are suitable for non-construction foams used in the United States, such as appliance insulation, and for a wide range of foreign (e.g., European) rigid foam applications, including building construction. Ranging from an Index of 1.5 up to 3.0, the ~oams of Examples 16 and 17 provide good insulating properties with differing flammability resistance.

T ~ LE IX
T~MO~l-Lll~G FO~ E~ PLES 9 - 15 ~U.. ~UN~ '~L, pbwEx. 9 Ex.10Ex.11 Ex.12 Ex.13 Ex.14 Ex.15 PS-2502A100.0 100.0100.0 100.0100.0 100.0 100.0 Fyrol PCF15.0 15.0 15.0 15.0 15.0 15.0 15.0 Dabco K-154.0 4.0 4.0 4.0 4.0 4.0 4.0 Amine C~t. 0.3 0.3 0.30.3 0 3 0 3 0.3 Silicone2.5 2.5 2.5 2.5 2.5 2.5 2.5 Prop. C~rb. 5.0 10.0 10.010.0 10.0 10.0 lO.0 Texaco NP95 5.0 0.0 0.00.0 0.0 0.0 0.0 Acetone~0.0 0.0 0.0 10 44 o.o 0.0 o.o Methyl Acetate~ 0.0 0.0 0.00.0 0.0 10.99 0.0 Methyl Alcchol~ 0.0 0.0 0.0o.o 0.0 0.0 4.06 Propane~0.0 1.0 0.0 0.0 0.0 0.0 0.0 Iso-Butane~ 0.0 0.0 4.10.0 0.0 0.0 0.0 Water 1.5 0.0 0.0 0.0 0.0 0.0 0.0 SYNCP 20.0 28.725.6 18.5626.82 18.01 24.94 TOTAL B-SIDE 153.3161.5 161.5160.8 160.8 160.8 160.8 Lupr. M70L 230.0178.8 178.8178.8 178.8 178.8 178.8 Silicone0.5 0.5 0.5 0.5 0 5 0.5 0-5 TOTAL A-SIDE 230.5179.3 179.3179.3 17g.3 179.3 179.3 TOTAL FOAM 383.8340.8 340.8340.8 340.8 340.8 340.8 Foam Index 2.68 3.0 3.03.03.0 3.0 3.0 Flame Spread 36 les6 les6le6s le6& less le3s Index thanthan thanthan than than 3 0 ~ "The6e polar organic expansion agent6 are mixed at the weight percent ratio with the 6pecial ~ynthesiz~d cyclor-n~r - which form~ an azeotrcpe bciling at a lower temperature th~n either _ _~..cnt ~lone.
~These ~lkaneG are mixed with ~pecial 6ynthe6ized cyclop~ntane in a weight ratiowhich produce~ the sa~e vapor-prcff~ure-ver6es-temperature curve a~ CFC-11.

CA 022ll676 l997-08-l4 W 096125443 PCTrUS96/02063 TABLE X
T~r~MQS~ N~ FOAM EX~i~PLES 16 - 17 5 ~u.. ~u.. ~, pbw Ex. 16 Ex.17 Stepan 2352 51.00 51.0 Vor~ol 280 49.00 49.0 Fyrol PCF 15.0 15.0 D~bco X-15 4.5 2.0 Prop. Carb. 5.0 5-0 Tex~o NP95 5.0 5.0 OSI-51000 2.47 2.47 PM-DETA 0 25 0.15 ~ater0 379 0.379 SYNCP21.72 21.72 TOTAL B-SIDE 154.3 151.72 PMDI213.10 104.0 DC-5098 0,53 0 53 SYNCP10.66 5.2 TOTAL A-SIDE 224.29 109.73 TOTAL POAM 378.60 261.45 Fo~m Index 3.0 1.5 Flam~ Spread ~75 ~450 Index For the present invention, a majority (e.g., greater than 50~ parts by weiyht) o~ the polyol component should be polyester polyol, although as shown in TABLE X a minority o~ the polyol component may be a polyether polyol (e.g., Voranol 280).

Wo 96125443 PCT~US96/02063 When selecting various ~lame retardants, the advantages of synthetic cyclopentane (SYNCP) was again demonstrated. As in T~BLE IV and TABLE V above, TABLE
XII below shows the Brook~ield viscosities o~ blend examples 23A - 23F o~ TABLE XI. Blend examples 23A -23F differ only in the particular flame retardant utilized (the same amount o~ ~lame retardant being utilized in each example). As seen in TABLE XI, the only flame retardant soluble in both types of pentane (e.g., both SYNCP and EXTRCP) is Fyrol PBR.

TABLE XI
FOA~ABLE BLEND EXA~PLES 23A - 23F
Chemicals Pbw Stepan PS-2502A 100.0 Flame Retardant 15.0 Propylene Carbonate 5.0 Texaco NP-95 5.0 Dabco K-15 3.2 Tertiary Amine 0.1 Silicone Surfactant 2.6 Pentane 23.5 TABLE XII
BROOKFIELD VISCOSITY AT 65~F
Example FlameSYNCP EXTRCP
Retardant 23A Fyrol PCF 1184 1784~
23B Fyrol DMMP 644 1040*
23C Fyrol CEF 1564 2712~
23D Fyrol-61520 2296*
23E Fyrol-PBR1680 1940 23F Fyrol-21540 2092~

In TA~3LE XII, an asterisk (*) indicates an unstable (e.g., separated) mixture.

The amount of liquid flame retardant should be in the range of 5 - 30 pphp (parts per hundred polyol), and preferably is in the range of 10 - 20 pphp.

The preferred levels of propylene carbonate utilized are in the range of 5.00 pphp to 15.0 pphp, with the most preferred embodiment being 7.5 to 10.0 pphp. The preferred range of organic non-ionic surfactant utilized is between 0.0 and 10.0 pphp, with the most preferred embodiment being from 5.0 to 10.00 pphp. It was discovered that an equal weight ratio of propylene carbonate to non-ionic organic surfactant was the optimum balance of these different types of diluent.

As understood by those skilled in the art, the term "Index~ as employed herein refers to the ratio of isocyanate functional groups to polyol functional groups.

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 o~ the invention.

Claims (30)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of producing a rigid thermosetting plastic foam, the method comprising the steps of;
(1) preparing a first of two foam forming blends using polymeric polymethylene polyphenylisocyanate;
(2) preparing a second of two foam forming blends by mixing together:
[a] a polyol component comprised of a majority of polyester polyol;
[b] a liquid flame retardant;
[c] a suitable catalyst to promote the reaction between the first of two foam forming blends and the polyol component; and, [d] a blowing agent comprised at least partially from depolymerization of dicyclopentadiene to yield cyclopentane; and, (3) mixing together the first and second foam forming blends to form the rigid thermosetting plastic foam.

2. The method of claim 1, wherein the cyclopentane obtained from step (2[d]) permits both the first and second foam forming blends to be substantially devoid of an organic surfactant.

3. The method of claim 1, wherein the foam has a ratio of isocyanate functional groups to polyol functional groups greater than 1.5:1Ø

4. The method of claim 1, wherein the blowing agent comprised at least partially of the reaction product of the reactions:
i) the depolymerization of dicyclopentadiene into unsaturated five-carbon hydrocarbons; plus, ii) the catalytic hydrogenation of the unsaturated five-carbon hydrocarbons into cyclopentane.

5. The method of claim 1, wherein other foam expansion agents are utilized with said blowing agent.

6. The method of claim 5, wherein the other foam expansion agents are alkanes having four or less carbon atoms.

7. The method of claim 5, wherein the other foam expansion agents are polar organic solvents forming azeotropes with cyclopentane.

8. The method of claim 5, wherein the other foam expansion agents are partially hydrogenated chlorofluorocarbons.

9. The method of claim 5, wherein the other foam expansion agents are partially hydrogenated fluorocarbons.

10. The method of claim 1, wherein the liquid flame retardant is chosen from a group consisting of tri(2-chloroisopropyl)phosphate, tricresyl phosphate, tri(2-chloroethyl)phosphate, tri(2,2-dichloroisopropyl)phosphate, diethyl N, N-bis(2-hydroxyethyl) aminomethylphosphonate, dimethyl methylphosphonate, tri(2,3-dibromopropyl)phosphate, tri(1,3-dichloropropyl)phosphate, and tetra-kis-(2-chloroethyl)ethylene diphosphate.

11. The method of claim 1, wherein the said reaction product is at least 95% pure cyclopentane.

12. The method of claim 1, wherein the polyol component is a polyester polyol having a hydroxyl number between 190 and 340.

13. The method of claim 1, wherein the polyol component is comprised of greater than 50% by weight polyester and less than 50% by weight polyether polyol.

14. The method of claim 1, wherein the second of the two foaming blends is a clear, stable mixture having a Brookfield viscosity below 1700cps at 77°F.

15. The method of claim 1, wherein one of the forming blends includes an organic carbonate.

16. A thermosetting plastic foam solid produced by the method of claim 1.

17. A thermosetting plastic foam solid produced by the method of claim 2.

18. A thermosetting plastic foam solid produced by the method of claim 3.

19. A thermosetting plastic foam solid produced by the method of claim 4.

20. A thermosetting plastic foam solid produced by the method of claim 5.

21. A thermosetting plastic foam solid produced by the method of claim 6.

22. A thermosetting plastic foam solid produced by the method of claim 7.

23. A thermosetting plastic foam solid produced by the method of claim 8.

24. A thermosetting plastic foam solid produced by the method of claim 9.

25. A thermosetting plastic foam solid produced by the method of claim 10.

26. A thermosetting plastic foam solid produced by the method of claim 11.

27. A thermosetting plastic foam solid produced by the method of claim 12.

28. A thermosetting plastic foam solid produced by the method of claim 13.

29. A thermosetting plastic foam solid produced by the method of claim 14.

30. A thermosetting plastic foam solid produced by the method of claim 15.