Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
  • C08G65/02—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring
  • C08G65/04—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers only
  • C08G65/06—Cyclic ethers having no atoms other than carbon and hydrogen outside the ring
  • C08G65/16—Cyclic ethers having four or more ring atoms
  • C08G65/20—Tetrahydrofuran
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
  • C08G65/02—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring
  • C08G65/30—Post-polymerisation treatment, e.g. recovery, purification, drying

Definitions

• This disclosure relates to the production of polyether polyols. More
• THF also known as polytetramethylene ether glycols (PTMEG)
• PTMEG polytetramethylene ether glycols
• PTMEG can be produced by many known processes. As discussed in U.S. Patent No. 4,120,903, herein incorporated in its entirety by reference, the
• PTMEG polytetramethylene ether glycol
• the key parameter that influences the color growth is the presence of oxygen. It has been found that oxygen can be introduced in substantial amounts during the loading and storage process. The oxygen, in synergistic combination with higher than allowable temperatures, can accelerate the oxidation reaction resulting in poor quality as delivered to the customer.
• the present invention relates to a method of minimizing the color growth in a polyether polyol product during storage, loading and shipping.
• the color growth is minimized by maintaining the temperature in the storage and loading tanks below a set temperature, replacing substantially all of the air in the storage and loading tanks with inert gas, and providing an anti-air intrusion system within the storage and loading tanks.
• An embodiment of the present invention comprises the steps of:
• the temperature of the storage and loading tanks is maintained below 75°C, such as, for example, from about 50°C to less than 75°C.
• replacing substantially all of the air in the storage and loading tanks prior to filling the tanks with the polyether polyol product is accomplished by a make-up gas system with which inert gas is pumped into the storage and loading tanks through conservation vents.
• the anti-air intrusion system consists of pumping an inert gas into the storage and loading tanks through conservation vents after filling the tanks with the polyether polyol product.
• the inert gas used replacing substantially all of the air in the storage and loading tanks prior to filling the tanks with the polyether polyol product is nitrogen.
• the inert gas used for the anti-air intrusion system is nitrogen.
• the color growth is maintained below 10 APHA units.
• the color growth is maintained below 5 APHA units.
• the polyether polyol product is poly(tetramethylene ether) glycol or a copolymer thereof.
• the polyether polyol product is combined with a polymerization stabilizer.
• the polymerization stabilizer is butylated
• FIG. 1 is a flow chart for an embodiment of the present invention.
• FIG. 2 is a chart showing the effect of temperature on the color growth of the polyether polyol product.
• the present invention relates to a method of minimizing the color growth in a polyether polyol product during storage, loading and shipping.
• the color growth is minimized by maintaining the temperature in the storage and loading tanks below a set temperature, replacing substantially all of the air in the storage and loading tanks with inert gas, and providing an anti-air intrusion system within the storage and loading tanks.
• PTMEG poly(tetramethylene ether) glycol.
• PTMEG is also known as polyoxybutylene glycol.
• THF tetrahydrofuran and includes within its meaning alkyl substituted tetrahydrofuran capable of copolymerizing with THF, for example 2-methyltetrahydrofuran, 3- methyltetrahydrofuran, and 3-ethyltetrahydrofuran.
• color value refers effectively to yellowness in the visible light spectrum of the product as viewed in total transmission.
• the polyether polyol is poly(tetramethylene ether) glycol (PTMEG).
• PTMEG poly(tetramethylene ether) glycol
• the PTMEG product is to be stored and loaded for transport, wherein oxidation of the PTMEG product would cause unwanted color growth.
• Fig. 1 depicts a flow chart showing the movement of the PTMEG product before reaching the customer (300).
• PTMEG manufacturing plants have several storage tanks (100). PTMEG temperatures in these tanks are 80- 1 10°C. Each tank is provided with an internal bayonet steam heater and a powerful centrifugal pump. The purpose of the pump is to not only transfer the PTMEG to the loading and storage tanks (200) but also to allow PTMEG to circulate to ensure that the various batches are adequately mixed to ensure a blend of uniform quality with no stratification in product specification.
• pumps allow enormous amount of PTMEG to circulate to minimize the blending time. During this process heat is generated which results in increased tank temperature.
• the PTMEG product temperature is about 80 °C as it leaves the manufacturing process and the temperature is increased further which is attributed (1 ) primarily to the circulation pump and (2) secondarily to the malfunctioning of the electric trace overheating the content.
• the PTMEG product is then pumped into the storage and loading tanks (200).
• the temperature of the storage and loading tanks is maintained below 75°C, such as, for example, from about 50°C to below 75°C.
• the product can be cooled prior to entering the storage and loading tanks by using conventional manufacturing techniques, such a water cooler. After the PTMEG product has been pumped into the storage and loading tanks, the product is considered to be a homogenous blend of uniform quality. Therefore, circulation pumps are only used sparingly at this point, primarily to transfer the PTMEG product for shipping. This prevents the temperature of the PTMEG product from rising above 75°C.
• substantially all of the air in the storage and loading tanks (200) is replaced with an inert gas.
• the air in the storage tanks is replaced by a make-up gas system with which inert gas is pumped into the storage and loading tanks through conservation vents.
• the storage and loading tanks (200) are checked to ensure the oxygen level is below 2%, such as, for example, from about 0 to below 2%.
• an anti-air intrusion system is provided within the storage and loading tanks (200) to prevent additional oxygen from entering.
• the anti-air intrusion system consists of pumping an inert gas into the storage and loading tanks through conservation vents after filling the tanks with the PTMEG product.
• the storage and loading tanks (200) are checked to ensure the oxygen level is still below 2% before shipping to customers (300).
• the make-up gas used to replace the air in the storage and loading tanks and for the anti-air intrusion system can be any inert gas void of oxygen.
• the inert gas is nitrogen.
• the color growth is measured by determining a first color value of the polyol product prior to entering the storage and loading tanks, determining a second color value after the polyol product has been pumped into the storage and loading tanks, and measuring the difference between the first color value and the second color value.
• color value refers effectively to yellowness in the visible light spectrum of the product as viewed in total transmission.
• the color value is indicated by an APHA index that is measured according to the method described in ASTM 1209.
• ASTM 1209 the measurement of and the color index assigned is based upon the ASTM D1209 method which correlates to the physical APHA/PtCo Color Index described in the ASTM method.
• the APHA/PtCo color index is
• the color growth of the polyol product is maintained below 10 APHA units. In another embodiment of the present invention, the color growth of the polyol product is maintained below 5 APHA units.
• the polyether polyol product is combined with a polymerization stabilizer.
• the polymerization stabilizer is butylated hydroxytoluene (BHT).
• Example 1 illustrates the increase of color growth of the polyether polyol product at increased oxygen levels.
• 100-200 gram samples of 1000-2000 grade Terathane T PTMEG product were taken from the manufacturing process via a DOPAK TM sampler. The samples were heated in an oven to 90 °C.
• oxygen was prevented from entering by the use of nitrogen padding.
• the color value of the sample was tested over a 24 hour period using the HunterLab ColorQuest II spectro-colorimeter described above. After 24 hours of testing, the first sample showed a mean color growth of 1.86 AHPA units.
• a second sample of the PTMEG was taken and was exposed to the atmosphere to allow oxygen containing air to enter. After 24 hours of testing, the mean color growth of this sample was found to be 10.57 AHPA units. Consequently, the effect of maintaining low oxygen levels in the PTMEG product to prevent color growth was clearly shown.
• Example 2 illustrates the increase of color growth of the polyether polyol product at increased temperature levels.
• 100-200 gram samples of 000-2000 grade TerathaneTM PTMEG product were taken from the manufacturing process via a DOPAKTM sampler. The samples were exposed to the atmosphere to allow miminal levels of oxygen to enter. The samples were then tested at various temperatures to show the effect on color growth. The results of the test are
• a method for minimizing color growth in a polyether polyol product during storage and loading comprises the following steps. Initially, a polyether polyol product to be stored and loaded for transport is provided, wherein oxidation of the polyether polyol product would cause unwanted color growth. The system of storage and loading tanks are maintained below a set temperature to prevent oxidation of the polyether polyol product. Prior to filling the tanks with the polyether polyol product, substantially all of the air in the storage and loading tanks is replaced with inert gas. Finally, an anti- air intrusion system is provided within the storage and loading tanks to prevent additional air from entering.
• Example 3 The process of Example 3 is repeated with additional steps. In this example, the temperature of the storage and loading tanks is maintained below 75°C.
• Example 4 The process of Example 4 is repeated with additional steps.
• replacing substantially all of the air in the storage and loading tanks prior to filling the tanks with the polyol product is accomplished by a make-up gas system with which inert gas is pumped into the storage and loading tanks through conservation vents.
• Example 5 The process of Example 5 is repeated with additional steps.
• the anti-air intrusion system consists of pumping an inert gas into the storage and loading tanks through conservation vents after filling the tanks with the polyol product.
• Example 5 The process of Example 5 or Example 6 is repeated with additional steps.
• the inert gas is nitrogen.
• Example 9 The process of Example 7 is repeated with additional steps. In this example, the color growth of the polyether polyol product is maintained below 0 APHA units. Example 9
• Example 8 The process of Example 8 is repeated with additional steps. In this example, the color growth of the polyether polyol product is maintained below 5 APHA units.
• Example 9 The process of Example 9 is repeated with additional steps.
• the polyether polyol product is poly(tetramethylene ether) glycol or a copolymer thereof.
• Example 10 The process of Example 10 is repeated with additional steps.
• the polyether polyol product is combined with a polymerization stabilizer.
• Example 11 The process of Example 11 is repeated with additional steps.
• the polymerization stabilizer is butylated hydroxytoluene (BHT).
• ratios, concentrations, amounts, and other numerical data may be expressed herein in a range format. It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited.
• a concentration range of "about 0.1 % to about 5%” should be interpreted to include not only the explicitly recited concentration of about 0.1 wt% to about 5 wt%, but also the individual concentrations (e.g., 1 %, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.5%, 1.1 %, 2.2%, 3.3%, and 4.4%) within the indicated range.
• the term “about” can include ⁇ 1 %, ⁇ 2%, ⁇ 3%, ⁇ 4%, ⁇ 5%, ⁇ 8%, or ⁇ 10%, of the numerical value(s) being modified.
• the phrase "about 'x' to 'y'" includes “about 'x' to about y".

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polyethers (AREA)

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• 2011
  • 2011-10-28 CN CN2011103337579A patent/CN102923387A/zh active Pending
• 2012
  • 2012-07-31 EP EP12745959.2A patent/EP2742082A1/en not_active Withdrawn
  • 2012-07-31 KR KR1020147005991A patent/KR20140064837A/ko not_active Application Discontinuation
  • 2012-07-31 WO PCT/US2012/048915 patent/WO2013022644A1/en active Application Filing
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