Patent Application
20070238799
The invention described herein provides a technology that is able to provide odorless polyester polyols that can then be used for making odorless polyurethane foams for, among other things, cosmetic uses. It further provides a method for converting an odorless polyester polyol into a substantially odorless polyurethane foam, which substantially odorless foam is useful in cosmetic formulations as noted herein. As used herein, “substantially odorless” means that the polyol or resulting polyurethane exhibit little discernible odor and that to the extent odor is present it is difficult to detect and mild and would otherwise not interfere with a chosen fragrance for a resulting cosmetic or other product incorporating the polyol or polyurethane foam or would not be overtly detectible to a user of a “fragrance free” cosmetic or other product, and “substantially odorless” also encompasses virtually completely odor free and completely odor free within its scope.
The main component in a substantially odorless foam is an odorless polyester polyol. The polyester polyol is initially manufactured by production methods that would produce a standard foam grade polyester polyol. These products typically have a number average molecular weight of between about 1000 and about 4000, an equivalent weight between about 500 and about 2000, a hydroxyl value between about 28 and about 110 and a hydroxyl functionality between about 2.0 and about 3.5.
Such a polyester polyol is generally manufactured from adipic acid and one or more linear glycols such as diethylene glycol, ethylene glycol, 1,3 propanediol, 1,4 butanediol and 1,6 hexanediol. In addition, small amounts of higher functionality alcohols such as glycerin or trimethylolpropane can be included to increase the hydroxyl functionality. Examples of these typical polyester polyols are Lexorez® 1102-50AT, Lexorez® 1102-50FT, and Lexorez® 1102-60FT, each of which is manufactured by and available from the Inolex Chemical Company of Philadelphia, Pa.
The polyester polyols as noted above are made odorless in accordance with the invention by an additional post-treatment that removes volatile odorous impurities.
The odorless foams of the present invention are made from aromatic isocyanates such as toluene diisocyanate (TDI) as a reactive ingredient, and use water as the primary blowing agent. The amount of isocyanate should be approximately stoichiometric such that the total number of isocyanate groups per unit mass should be within about 15% of the total amount of reactive hydroxyl, water and amine groups in the same mass.
The substantially odorless foam formulation preferably includes a catalyst to control the rate of reaction. Preferred catalysts for use in the invention include tertiary amines or ureas that have been selected so as to impart substantially no odor in the final foamed article. This can be accomplished by any technique that may render the amine non-volatile. Specific examples include DABCO® NE400, DABCO® NE500, DABCO® NE600 and DABCO® T, all available from Air Products and Chemicals in Allentown, Pa., and Jeffcat® ZF-10, Jeffcat® DMEA, Jeffcat® ZR-70, Jeffcat® ZR-50, Jeffcat® DPA, and Jeffcat® DPA-50, each available from Huntsman Corporation, Houston, Tex. Catalysts are present generally in an amount of about 0.1 to about 3.0 weight percent of the composition based on 100 parts by weight of polyester polyol.
A substantially odorless polyurethane foam further preferably includes one or more interfacially active agents to emulsify the ingredients and stabilize the cellular structure before the polymer builds sufficient molecular weight to support itself. The preferred surfactant combination may contain separate ingredients for stabilization and emulsification, but all ingredients are most preferably compatible with the goal of making an odorless foam product. It has been found by the inventors herein that many commercial polyurethane foam surfactants impart excessive odor to the foam. Commercial examples of substantially odorless foam stabilizers are DABCO® DC4000 and DABCO® DC4020 available from Air Products and Chemicals and Silbykg 9110 from Byk Chemie. Surfactants are preferably present in the formulation in amount of from about 0.1 to about 3.0 weight percent based upon 100 parts of polyester polyol.
Optionally, fragrances, perfumes or dyes may be added to the foam formula to impart a desirable scent and/or coloration to the final foam product. These will likely affect the smell of the foam, and should not be considered an odor for the purpose of this invention. Other optional ingredients can be included in the odorless foam to impart specific performance properties. These include flame-retardants, fungicides, bactericides, anti-microbials, plasticizers, crosslinking polyols, UV-absorbers, thickeners, thixotropic agents, preservatives, diamines, antioxidants and so on. If additives such as these are present, they should be chosen such that they do not compromise the goal of producing a substantially odorless foam for cosmetic use. Beyond that requirement, optional ingredients that are known or to be developed may be used within the scope of the invention, but are not required. Additives can be provided in varying amounts. Preferably, the additives collectively make up no more than about 30 weight percent of the formulation based on 100 parts by weight of polyester polyol.
The polyester polyols according to the invention are made using a process in which the polyester polyols, preferably polyester polyols such as those described above, are stripped to be substantially free of odor so as to be useful for producing low odor polyurethane foams.
The polyester polyols are formed from compositions that include components such as those described above including at least one diacid and at least one monomeric diol and/or dimeric diol. As used herein “a” means one or more and is equivalent to “at least one” unless otherwise specified. Optionally included in the compositions are monomeric triols. The compositions can include diacids, diols and triols which are the same or different than a primary diacid, diol and/or triol. Preferably, the diacid is adipic acid, although it is within the scope of the disclosure to include various types of diacids commonly used and/or to be developed in the art for polyester polyol formation.
The monomeric and/or dimeric diols are preferably chosen to be alkyl or alkylene diols or glycols, such as, for example, but without limitation preferred compounds including ethylene glycol, propandiol, butanediol and diethylene glycol and combinations thereof.
Optional, useful monomeric triols, which can be incorporated in the compositions, include glycerin, trimethylol propane and trimethylolethane and combinations thereof. However, other triols or other high alcohols can also be used.
The polyester polyols are stripped by heating to above about 100° C. and injecting steam into the polyester polyol. The polyol is then preferably maintained at a temperature of about 100° C. to about 150° C. upon injection of the steam.
The treatment preferably occurs in a stripping vessel in which steam may be injected which has heating capability through whatever acceptable source. The vessel and its contents, including the polyester polyol are preferably kept at a pressure which is less than ambient, more preferably at less than about 100 torr and most preferably less than about 20 torr.
Steam is preferably continuously injected into the vessel at a rate of about 0.002 to about 0.04 pounds/hour/pound of polyester, more preferably 0.006 to about 0.015 pounds/hour/pound polyester. The stripping step preferably lasts about 0.1 to about 25 hours, and more preferably about 1 to about 10 hours.
It is exceedingly difficult to develop a useful machine method to quantify odor properties. Therefore, trained volunteers were used to measure the odor by qualitatively ranking the various specimens. The odor testing was done in a blind study with appropriate controls introduced to ensure consistency. Polyester polyol odor testing was done with Inolex Chemical Company test method QCM116. In this test, approximately 4 ounces of the polyester is added to an 8 ounce glass jars. The judges then rate the odor of the contents immediately after opening the jar on a scale of 0 (odorless) to 10 (suffocating).
The following example illustrates preferred embodiments of odorless polyester polyols that can be used to manufacture odorless polyurethane foams suitable for cosmetic uses. Further examples demonstrate the method for producing essentially odorless polyurethane foams from these odorless polyester polyols, as well as the olfactory properties of the essentially odorless foams for cosmetic uses.
Manufacture of Base Polyester Polyols (Polyol A and Polyol B):
A three-component polyester polyol (Polyol A) was made from 375 pounds of adipic acid, 294 pounds of diethylene glycol and 13 pounds of glycerin. A catalytic amount (37 grams) of tetrabutyl titanate was also added during the process.
These components were reacted at 200-230° C. for 22 hours. To produce a polyester polyol that had a typical sweet odor with a hydroxyl value of 54, equivalent weight of 1040 and viscosity of 22,000 centipoise at 25° C.
A three-component polyester polyol (Polyol B) was made from 375 pounds of adipic acid, 294 pounds of diethylene glycol and 13 pounds of glycerin. A catalytic amount (37 grams) of tetrabutyl titanate was also added. These components were reacted at 200-230° C. for 22 hours. The final polyester had a typical sweet odor with a hydroxyl value of 54, equivalent weight of 1040 and a viscosity of 22,500 cps at 25° C. Polyol A and Polyol B were made under duplicate conditions, and the final properties are quite similar.
A factory made sample of Lexorez® 1102-50FT was taken from the regular manufacturing process to serve as a control (Polyol C).
Process for Removing Odor Components of Polyol A and Polyol B:
Polyol A was treated to remove volatile, odorous impurities. In this process, 575 pounds of Polyol A was held between 110-130° C. while steam was injected into the material at a constant rate of 5 pounds per hour at 100 psig. During the 8 hour stripping process, the reactor was held at a vacuum of 10-20 torr. The resultant odorless polyol (Stripped Polyol D) had a final acid value of 1.17, hydroxyl value of 51.5, equivalent weight of 1090, viscosity of 23,4000 cps at 25° C. and a moisture of 0.010%.
Polyol B was treated to remove volatile, odorous impurities. In this process, 575 pounds of Polyol B was held between 110-130° C. while steam was injected into the material at a constant rate of 5 pounds per hour at 100 psig. During the 8 hour stripping process, the reactor was held at a vacuum of 10-20 torr. The resultant odorless polyol (Stripped Polyol E) had a final acid value of 1.18, hydroxyl value of 49.5, equivalent weight of 1130, viscosity of 24,000 cps at 25° C. and a moisture of 0.025%.
A trained panel of six (6) judges performed the odor testing on the polyester polyols using Inolex Chemical Company odor method QCM116. The judges were not advised of the identification of the sample until all testing was complete. The results appear below in Table 1.
A Table of Foam Ingredients appears below in Table 2
A series of polyurethane foams were prepared from combinations of the above ingredients in Table 2 that were chosen with the goal of producing a substantially odorless polyurethane foam for cosmetic use. The foams listed below in Table 3 were made by combining the ingredients in the stated ratios. TDI and polyol were premixed at slow speed for approximately 20 seconds. Immediately thereafter, the catalyst, water and surfactant were added. Then the components were mixed at approximately 2500 rpm for 6-7 seconds and poured into a rectangular box. The foam was allowed to react at room temperature, and within 3 minutes, all had reached full rise height. This technique is typical for bench scale simulation of the commercial foaming process. It is understood that the mechanical process of combining and mixing the ingredients is not part of the invention and only serves to produce specimens for further testing. Table 3 below illustrates Formulation Examples of Odorless Polyurethane Foams according to the invention.
As before, a trained panel of judges blindly assessed the odor of the foam samples. In each trial, a judge was given three foam samples, each contained in a sealed glass jar. In each set of samples, there was either one or two foams made with a stripped polyol and the rest were made with control (unstripped) polyols. The judge was asked to identify the one that was different and whether it was best or worst in the group. To avoid prejudicing the judge, they were not told how many foams with stripped polyol were in each trial set.
A total of 28 trials were conducted with 8 different judges. There were 14 “best” votes, 12 “worst” votes and 2 where the judge could determine no difference between the foams. Tallying the results, 10 of the 14 “best” votes and 0 of the 12 “worst” votes went to foams made with stripped polyol. This means that only 4 of the 26 sets were misidentified. Given the subjective nature of the test, these results are quite conclusive that the foams made with stripped polyol gave off significantly less odor.
It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.
This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 60/790,312, filed Apr. 6, 2006, the entire disclosures of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60790312 | Apr 2006 | US |
