MXPA96003380A - Polyols polyols of high molecular weight, low odor, a process for the production of them and its use for the production of polymers, cosmetics and pharmaceutical products synthetized from polyolylene polyols - Google Patents

Abstract

Polyether polyols of high molecular weight, with low odor, which are produced by the purification of polyether polyols at temperatures of 110 to 150 ° C and pressures of 10 to 70 hPa, with the addition of 5 to 30% in water peos are described. , where the water is passed in a finely divided form, with a droplet diameter of approximately 5 to 100 microns, through the polyether polyols to be purified, for a time of addition of 1 to 5 hours.

Description

POLYOLS OF HIGH MOLECULAR WEIGHT POLYETER, LOW ODOR, A PROCESS FOR THE PRODUCTION OF THEM AND ITS USE FOR THE PRODUCTION OF POLYMERS, COSMETICS AND PHARMACEUTICAL PRODUCTS SINTETIZED FROM POLYETER POLYOLS BACKGROUND OF THE INVENTION The present invention relates to polyether polyols of high molecular weight, low odor, to a process for the production thereof, and to their use for the production of polymers, cosmetics and pharmaceuticals synthesized from polyether polyols. The industrial production of polyether polyols is generally by alkoxylation of appropriate initiator compounds containing active hydrogen atoms of Zerewitinof f. This reaction produces a reaction mixture containing polyether polyols. However, the reaction mixture must be neutralized, dehydrated and subsequently filtered to eliminate the inorganic salts. Depending on the procedure used, the resulting polyether polyols contain from about 0.1 to 2% by weight of waste water, up to about 2% by weight of solvent (generally a REF: 22928 organic solvent) and odorous substances, such as aldehydes, dioxolanes, dioxanes, allyl alcohol, and allylic ethers of mono-, di-, and tri-propylene glycol. Although these odorous substances are generally only present in small amounts, they nonetheless impart an intense, characteristic aromatic odor to the polyether polyols. Various methods of purification in the art have therefore been developed and described, in order to eliminate the unwanted by-products of the polyether polyols, which arise from their production. Thus, German Patent DE-A-2,755,089, for example, describes an improved process for the removal of problematic by-products. This process refers specifically to the removal of small amounts of water and solvents, and also to low molecular weight glycols and substances with an intense odor, by means of a spiral tube evaporator. A disadvantage of this process, however, is that the organic solvents that are present are not completely eliminated and the substances with intense odor are only eliminated to a small degree. Yet another disadvantage of the process described in this German Patent is the high cost of the apparatus associated therewith. In principle, drop film evaporators can also be used for the purification of polyether polyols. However, these have the same disadvantages as the purification process by means of a spiral tube evaporator, which is described in the German patent described above. Japanese Patent Application No. 56 / 104,936 describes a process for the purification of polyether polyols in which, at a pH greater than 6.5, either 1) the crude polyether polyols are distilled under reduced pressure and at elevated temperature, or 2) water, steam or nitrogen are passed through the raw polyether polyols, likewise under reduced pressure and at elevated temperature. However, as the comparison example 2 of this Japanese patent application shows, problematic odorous substances are only removed to an insufficient degree when water is passed through the raw polyether polyol mixture. This is shown by the corresponding results of the analysis and odor tests. In addition, the polyether polyols obtained from the comparison example 2 were less durable, for example, the aldehyde content of the polyether polyols was increased as did the unacceptable odor. The aim of the present invention was to provide polyether polyols, from which - A - the odor-forming by-products have been eliminated, to the greatest extent possible, so that these polyether polyols are practically odor-free. The polyether polyols practically free of odor such as these, thus satisfy the current requirements, particularly when these are used to produce polyurethanes and flexible PU foams, which in turn are used in the production of furniture or mattresses. In addition, severe demands have been placed on the purity of polyether polyols used in the cosmetics industry, in the food packaging industry and in the pharmaceutical industry; the polyether polyols according to the invention are able to meet these demands, particularly being of neutral taste.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a process for the production of polyether polyols of high molecular weight, low odor; this process comprises the purification of the polyether polyols at temperatures of about 110 to 150 ° C, preferably about 115 to 140 ° C, and at a pressure of about 10 to 70 hPa, preferably about 20 to 50 hPa, with the addition from about 5.0 to 30.0% by weight, preferably about 7.0 to 25.0% by weight, of water, based on the amount of polyether polyols present, wherein the water is passed in a finely divided form with a droplet diameter of about 5.0 to 100 microns, preferably about 7 to 50 microns, through the polyether polyols to be purified, for a measured addition time of about 1 hour to 5 hours, preferably about 2 hours to 4 hours. The present invention also relates to low odor polyether polyols, which are monofunctional or polctional, and which have molecular weights from about 750 to 18,000, preferably from about 1,000 to 15,000, and more preferably from about 2,000 to 12,000, and a viscosity at 25 ° C from about 40 to 25,000, preferably from about 50 to 10,000 mPa • s. These polyether polyols are produced by purification of the polyether polyols at temperatures of about 110 to 150 ° C, and at pressures of about 10 to 70 hPa, wherein about 5 to 30% by weight of water (based on the amount of polyether polyols present) is metered into the polyether polyol in a period of about 1 hour to about 5 hours. The water that is dosed into the polyether polyols is in finely divided form and has a droplet diameter of about 5 to 100 microns. The process results in purified polyether polyols containing: a) less than 1.5 ppm of 2-methyl-2-pentenal, preferably less than 0.2 ppm, b) less than 1.0 ppm of allylic alcohol, preferably less than 0.2 ppm, c) less than 15 ppm of allyloxypropanol, preferably less than 5.0 ppm, d) less than 50 ppm of dipropylene glycol allyl ether, preferably less than 0.5 ppm, and e) less than 1.0 ppm propionaldehyde, preferably less than 0.2 ppm.

As used herein, the term "molecular weight" refers to the number-average molecular weight. This is based on OH number and functionality, and is easily calculated according to the formula: pM = F x 56,100 0H # where MP represents the number average molecular weight of the polyethylene glycol, F represents the functionality of the polyether polyol, and 0H # represents the OH number of the polyether polyol.

The viscosities herein are determined using a Hoppler viscometer according to DIN 53015. The polyether polyols to be purified according to the invention are produced, as is known in the art, by the polymerization of epoxides, such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin themselves, in the presence of acids for example, or by the addition of these epoxides, preferably in mixture or in succession, in the presence of acids or preferably from strong bases as catalysts, to the initiator components containing reactive hydrogen atoms. Some examples of initiator components of this type include compounds such as n-butanol, n-hexanol, phenol, water, ethylene glycol, 1,2- and 1,3-propylene glycol, 1,4-butanediol, 4,4 '. -dihydroxydiphenylpropane, glycerin, trimethylolpropane, erythritol, sorbitol, ammonia, ethylendiaraine, aniline, ethanolamine and triethanolamine. Sucrose polyethers, such as those described in, for example, German Descriptions Nos. 1, 176,358 and 1,064,938, and polyethers modified by vinyl polymers, such as those produced by the polymerization of styrene and acrylonitrile in the presence of polyethers (as described in, for example, US Pat. Nos. 3,383,351, 3,304,273, 3,523,093 and 3,110,695, the descriptions of which are incorporated by reference herein, and in German Patent DE-B 1,152,536), may also be purified according to the present invention. Preferred polyether polyols are those which are based on ethylene oxide and / or propylene oxide, which contain from 1 to 8, preferably from 2 to 6 hydroxyl groups, and the molecular weights and viscosities of which fall within the intervals given above. It is important for the process according to the invention that the measured or metered addition of the water be effected during the purification of the polyether polyols, such that the temperature does not fall below the lower temperature limit for distillation, and does not exceed the upper pressure limit. This is achieved by predetermination of the time required for the dosed addition of water, which is to be added at a controlled rate to the polyether polyols. If the predetermined distillation conditions are not respected, the odor-forming substances in the polyether polyols will only be removed to an insufficient degree. As * mentioned above, it is also important for the resulting purified polyether polyols of the present invention that the water be introduced into the polyether polyols in the form of very small droplets. This can be achieved, for example, by means of a capillary tube, a sintered metal frit or by means of small pressure nozzles or two fluid pneumatic nozzles. It is preferred that intensive and good mixing of the distillation mixture occurs, so that the introduced water is brought into intimate contact with the polyether polyols to be purified. Used mixing devices, such as cross arm agitators, grid agitators or ultratorax mixers, can be used for this purpose. The process according to the invention can be accommodated downstream of the production process of the polyether polyol, known, as a separate purification step. It is also possible, of course, to fasten the commercially available polyether polyols, in their doped form, to subsequent purification using the process according to the invention, in order to obtain commercially available polyether polyols in a practically free form. Of smell. The low-odor polyether polyols, according to the invention, can be used for the production of low-emission polymers, synthesized from polyether polyols, such as polyurethanes, particularly flexible polyurethane foams, or elastomers. , or for the production of cosmetics and pharmaceutical products and of -packaging- food. The invention is further illustrated, but is not intended to be limited by the following examples, in which all parts and percentages are by weight unless otherwise specified.

EXAMPLES In the following examples, 1000 g of the various polyols (as described below) were heated to 120 ° C. 200 g of water (20% by weight) were introduced at a pressure of 18 hPa by means of thin inlet tubes (diameter of 0.2 mm) at a rate such that the temperature did not fall below 120 ° C and the pressure did not fall. it rose above 40 hPa. The water was added to the unpurified polyether polyols in a period of 3 hours. The water vapor bubbles had an average diameter of 7 to 50 microns. Di- and trifunctional polymers of P0- and PO / EO were used in the examples. The effect of the purification according to the invention on the impurities in the polyether polyols used, is apparent from Table 1. It can be clearly seen that after purification, the unwanted by-products, which among others effects resulted in the formation of an odor, they were very intensively eliminated. The analysis was carried out by means of gas chromatography of the upper space.

Polyether polyol 1: an ethylene oxide / propylene oxide polyether initiated with glycerin, which is branched, having an OH number of about 46, a molecular weight of about 3660 and a viscosity of about 560 mPa » s.

Polyether polyol 2: a polyether of propylene oxide initiated with propylene glycol, which is linear, having an OH number of about 112, a molecular weight of about 1000 and a viscosity of about 140 mPa-s.

Polyether polyol 3: a polypropylene oxide polyester initiated with propylene glycol, which is linear, having an OH number of about 56, a molecular weight of about 2000 and a viscosity of about 310 mPa «s.

Polyether polyol 4: a polyether of propylene oxide / ethylene oxide, initiated with trimethylolpropane, which is branched, having an OH number of about 28, a molecular weight of about 6000 and a viscosity of about 1120 mPa-s .

Table 1 Compounds in Examples 1 Example 2 Polyether polyols Polyether polyol 1 Polyether 2 polyol before the after the before the purification purification purification purification 1,4-dioxane < 0.1 < 0.1 < 0.1 < 0.1 2, -dimethyl-l, 3-dioxolane 1.5 < 0.1 < 0.1 < 0.1 2-ethylene-4-methyl-1,3-dioxolane 2.5 < 0.1 < 0.1 < 0.1 2-methyl-2-pentenal 1.8 < 0.1 2.2 < 0.2 acetaldehyde 1.2 0.1 1.9 2 allyl alcohol < 0.1 < 0.1 0.6 < 0.1 allyl-oxypropanol 80 < 0.1 0.6 < 0.1 butyraldehyde < 0.1 < 0.1 < 0.1 < 0.1 allyl ether of DPG 460 < 0.1 480 < 0.1 propionaldehyde 1.1 0.1 0.4 0.3 sum of volatile compounds clearly unknown 20 15 (all data are in ppm) Table 2 Compounds in Example 3 Example 2 before the after the before the purification after the purification purification purification 1,4-dioxane < 0.1 < 0.1 < 0.1 < ro? 2,4-dimethyl-l, 3-dioxolane < 0.1 < 0.1 < 0.1 < 0? 2-ethylene-4-methyl-1,3-dioxolane 1.2 < 0.1 < 0.1 < 0.1 2-methyl-2-pentenal 6 0.3 0.3 < 0.1 acetaldehyde 0.5 0.8 0.6 1.3 allyl alcohol 1.8 < 0.1 < 0.1 < 0.1 allyl-oxypropanol 170 1.4 12 0.3 butyraldehyde < 0.1 < 0.1 < 0.1 < 0.1 DPG 650 allyl ether < 0.1 55 < 0.1 propionaldehyde 2.7 0.1 0.3 0.3 sum of volatile compounds clearly unknown (all data is in ppm) Although the invention has been described in detail in the foregoing for purposes of illustration, it should be understood that such details are solely for that purpose, and that variations may be made therein by those skilled in the art, without departing from the spirit and scope of the invention, except as may be limited by the claims.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, property is claimed as contained in the following:

Claims (9)

1. A process for the production of a low odor polyether polyol, which may be monofunctional or polyfunctional, and having a molecular weight from about 750 to 18,000, and a viscosity at 25 ° C of about 40 to 25,000 mPa • The process is characterized in that it comprises: 1) purification of the polyether polyol at temperatures of about 100 to 150 ° C and at pressures of about > 10 to 70 hPa, wherein approximately 5 to 30.0% by weight of water, based on the amount of polyether polyol present, is metered into the polyether polyol in a period of time from about 1 hour to about 5 hours, said water in a finely divided form and having a droplet diameter of 5 to 100 microns, wherein the resulting polyether polyol contains a) less than about 1.5 ppm of 2-methylpentenal, b) less than about 1.0 ppm of alcohol allyl, c) less than about 15 ppm of allyloxypropanol, d) less than about 50 ppm of dipropylene glycol allyl ether, and e) less than about 1.0 ppm of propionaldehyde.

2. The process according to claim 1, characterized in that the polyether polyol has a molecular weight of about 1000 to about 15,000, and a viscosity of about 50 to 10,000 mPa-s at 25 ° C.

3. The process according to claim 2, characterized in that the polyether polyol has a molecular weight of from about 2000 to about 12,000.

4. The process according to claim 1, characterized in that from 7 to 25% by weight of water, based on the amount of polyether polyol pre-sit, is metered into the polyether polyol in a period of about 2 to 4 hours, the water having a droplet diameter of about 7 to 50 microns.

5. The process according to claim 1, characterized in that the distillation is at temperatures of about 115 to 140 ° C, and at pressures of about 20 to 50 hPa.

6. The low-odor, poly-functional poly-functional polyether polyol characterized in that it is produced by the process according to claim 1.

7. The polyether polyol according to claim 6, characterized in that it has molecular weights from 1000 to 15,000, and a viscosity from 50 to 10,000 mPa • s at 25 ° C.

8. The polyether polyol according to claim 6, characterized in that a) the 2-methyl-2-pentenal is present in an amount of less than about 0.2 ppm, b) the allylic alcohol is present in an amount of less than about 0.2. ppm, c) the allyloxypropanol is present in an amount of less than about 5.0 ppm, d) the dipropylene glycol allyl ether is present in an amount of less than about 0.5 ppm, and e) the propionaldehyde is present in an amount of less than about 0.2 ppm.

9. In a process for the production of a polyurethane comprising the reaction of a polyisocyanate with an isocyanate-reactive component, via the polyisocyanate polyaddition process, an improvement characterized in that the isocyanate-reactive component comprises the monofunctional or polyfunctional polyether polyol. , of low odor, according to claim 6.