Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
1999-09-09
2002-07-16
Sergent, Rabon (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C252S182200, C252S182240, C252S182280, C252S182290, C521S115000, C521S116000, C521S130000, C521S131000, C521S170000, C521S172000, C521S173000, C521S174000, C521S176000
Reexamination Certificate
active
06420443
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a process for preparing hydrocarbon blown, rigid polyurethane foam using a novel compatibilizing agent.
Many of today's rigid foam formulations have been optimized for desirable processing and property characteristics using such common blowing agents as F-11 and HCFC-141b. Due to environmental concerns and associated legislative pressures, these and similar materials are being phased out over varying timetables in different countries. These market changes have created a need for alternative blowing agents for rigid foam applications. One of these potential alternatives involves the use of hydrocarbon blowing agents, such as isomers of pentanes and butanes, in place of the widely used and historical chlorofluorocarbons (CFC's), hydrochlorofluorocarbons (HCFC's), and hydrofluorocarbons (HFC's). Unfortunately, these low polarity hydrocarbon blowing agents frequently possess limited compatibility with standard foam formulations optimized for the halogenated additives. Accordingly in the near term, the industry urgently needs additives that will improve the compatibility of these new blowing agents with the time-proven processing equipment and formulation chemistries. In time, evolving chemistries and/or manufacturing processes may obviate this compatibilizer need, but the industry needs tractable solutions today to meet current environmental and market demands.
Much art exists in the rigid polyurethane foam field detailing additives that render hydrocarbons more compatible with standard rigid foam formulation mixtures. This specific invention addresses additional novel additives and mixtures of additives that render hydrocarbon blowing agents more compatible with rigid foam formulations, possibly resulting in density reduction and more efficient use of the blowing agent.
WO 96/12759 (Dow) discloses a close-celled polyurethane foam comprising reacting in the presence of a hydrocarbon blowing agent, a polyisocyanate with a mixed polyol composition. This polyol mixture comprises a standard rigid polyol plus a compatibilizing agent containing the C
n
H
2n+1
fragment, where n is greater than or equal to 5, which contains at least one active hydrogen and not more than one aromatic group. Castor oil is illustrated. The compatibilizing agents may be alkoxylated derivatives of fatty oils. No criticality for alkoxylation is noted and, more particularly no criticality of ethoxylation is suggested. U.S. Pat. No. 5,451,615 (Dow), a related patent, details compatibilizing agents which are fatty oils with hydroxyl values of 100-200.
U.S. Pat. No. 5,484,817 and U.S. Pat. No. 5,464,562 describe a method for preparing close- celled rigid polyisocyanate foam comprising reacting polyisocyanate and polyol having ester linkages with a C
4
-C
7
hydrocarbon and a polyol additive. This additive is noted as a polyalkylene polyether monol (i.e. a mono hydroxy compound) based on a C
8
-C
24
fatty hydrocarbon with one active hydrogen atom.
U.S. Pat. No. 5,470,501 and U.S. Pat. No. 5,504,125 describe polyurethane foam formulations using a hydrocarbon C
4
-C
7
blowing agent and a compatibilizer. The noted compatibilizer is an optionally alkoxylated alkyl aromatic monol or derivative.
WO 98/42764 (ICI) discusses use of a mixture of two different polyoxyethylene polyether monols to solubilize hydrocarbon blowing agents in rigid polyurethane foams. C
12
-C
15
monols with 120-180 hydroxyl values are discussed as solubilizing agents.
Skowronski and Londrigan, (Jim Walter Research Corp.) SPI 29
th
Polyurethane Conference, 1985 page 76-83 describes foams based on surfactants prepared from castor oil ethoxylates unto which were grafted maleate and fumarate esters via free radical coupling chemistries. These surfactants were reportedly used in phenolic closed celled foams as well as polyurethane foams and were substitutes for traditional silicone surfactants. A related patent, U.S. Pat. No. 4,529,745 describes surfactants which are free radical reaction products of polyoxyalkylene adducts of organic triglycerides with dibasic esters that possess unsaturated C
4
-C
5
diacid cores and C
8
-C
18
alcohol derived tails. Ethoxylated castor oil and tridecyl fumarate are preferred building blocks of these grafted surfactants.
U.S. Pat. No. 5,684,092 describes polyurethane foams employing hydrocarbon blowing agents and a 1-4 carbon monol other than t-butanol.
U.S. Pat. No. 5,786,400 (Sumitomo Bayer Urethane Co., Ltd.: Japan) describes the use of t-butanol as a hydrocarbon emulsifier in rigid foams. Data in Table 3 of the citation shows it to be more efficient compatibilizer than a nonylphenol ethoxylate additive or no additive.
U.S. Pat. No. 4,751,251 (Dow Corning) describes a blend of silicone, organic surfactant and water or C
1
to C
3
alcohols as a generic compatibilizer package. The document claims no negative effect is produced on foam reaction catalysis, even with acid functional organic surfactant, and observes increased foam height when using these mixtures. The preferred organic surfactant is reported to be sodium dodecylbenzene sulfonate.
U.S. Pat. No. 5,736,588 (Bayer Aktiengesellschaft) uses solution promoters of a group consisting of dialkyl carbonates, certain dicarboxylic acid esters, certain triesters of phosphoric acid, certain fatty acid/diamine reaction products, and certain quartemary ammonium salts. U.S. Pat. No. 5,578,651 describes similar solubilizers used in polyurethane foams employing halohydrocarbon blowing agents.
SUMMARY OF THE INVENTION
This invention relates to rigid foam mixtures comprised of polyol(s), isocyanate(s), blowing agent(s), catalyst(s), optional additive(s), and specific compatibilizing additives. The invention further relates to a novel process for preparing hydrocarbon blown rigid polyurethane foam using a compatibilizing agent.
The compatibilizing agent utilized in the invention is (1) an alkoxylate adduct of a triglyceride with a hydroxyl value of less than about 100. The triglyceride adduct (1) has an ethylene oxide content of at least 40% by weight of the adduct. These adducts may be used alone or in mixtures with other compatibilizers. The compatibilizers increase the stability of rigid foam formulation emulsions containing hydrocarbon blowing agents while showing little or no adverse affect to physical properties of foams prepared therewith.
The alkoxylated triglyceride additive (1) may optionally be employed with one or more adducts (2) from the following: a polyoxyalkylene oxide monol, a capped polyoxyalkylene oxide adduct, and a fatty oil, including triglyceride(s) or alkoxylated triglyceride(s), other than those defined for triglyceride adduct (1).
Another aspect of the present invention is the polyurethane foam/article made by curing a composition of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The entire disclosures of all US patents and other published documents and any copending US patent applications mentioned anywhere herein are expressly incorporated herein by reference
This invention relates to rigid foam mixtures comprised of polyol(s), isocyanate(s), blowing agent(s), catalyst(s), optional additive(s), and the compatibilizing additive of the invention. The compatibilizing agent(s) of this invention greatly enhance the stability of rigid foam formulation emulsions, particularly when prepared with higher hydrocarbon blowing agent levels. Compatibility improvements of 15% or more, as measured by an ability to relatively increase hydrocarbon levels without breaking the emulsion, can generally be obtained with the invention, often greater than 50%. In preferred embodiments of the invention the foam system can tolerate increased hydrocarbon levels which are 75% more higher than levels obtainable with conventional compatibilizers.
Rigid foam as discussed in this invention is one defined by its application. It is typically a fine, closed-cell foam material with ample bulk physical integrity and self-supporting character such as to be used as laminated building panels structur
Clark R. Christopher
Hilker Brian L.
Crompton Corporation
Dilworth Michael P.
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