Method for making polycarbonate
A technology of polycarbonate and diaryl carbonate, which is applied in the field of polycarbonate preparation and can solve problems such as adverse effects on moldability and toughness
Inactive Publication Date: 2006-12-13
SABIC GLOBAL TECH BV
View PDF0 Cites 2 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Although low levels of Fries products can be tolerated in polycarbonate products prepared by the melt process, the presence of high levels of Fries products can adversely affect polycarbonate performance characteristics such as moldability and toughness
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment 1-3 and comparative Embodiment 1-6
[0061] For ease of observation and assurance of purity, the melt transesterification reaction was performed in a 1-liter glass batch reactor equipped with a solid nickel helical stirrer. The bottom of the reactor has breakaway glass connections to remove the final melt. To remove all sodium from the glass vessel, the reactor was soaked in 3N HCl for at least 12 hours, then in 18 Mohm water for at least 12 hours. The reactor was then dried overnight in an oven and stored covered until use. The temperature of the reactor was maintained with a fluidized sand bath with a PID controller, and the temperature was measured near the reactor and sand bath interface. The pressure control in the reactor is controlled by introducing nitrogen into the vacuum pump downstream of the distillation collection flask, measured with a mercury barometer at high pressure (760mmHg-40mmHg), and measured with an Edwards thermal manometer at low pressure (40mmHg-1mmHg).
[0062] Before installation, so...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
| Property | Measurement | Unit |
|---|---|---|
| number average molecular weight | aaaaa | aaaaa |
| number average molecular weight | aaaaa | aaaaa |
| number average molecular weight | aaaaa | aaaaa |
Login to View More
Abstract
Polycarbonates having a high level of endcapping and containing a low level of Fries rearrangement product are prepared from dihydroxy aromatic compounds, such as bisphenol A, and diaryl carbonates such as diphenyl carbonate in a two stage process involving a tetraalkyl phosphonium carboxylate catalyzed oligomerization of the reactants in a first reaction stage followed by the addition of an alkali metal hydroxide co-catalyst in the second stage of the polymerization reaction. The late addition of the co-catalyst provides improved polymerization reaction rates as judged by higher polycarbonate molecular weights. The amount of alkali metal hydroxide co-catalyst is small thus avoiding the formation of excessive amounts of Fries product. The method has been used to provide Fries product levels between 200 and 1000 parts per million in polycarbonates having Mn values of at least 7,500 Daltons.
Description
Background of the invention [0001] The present invention relates to the preparation of polycarbonates by a two-stage melt polymerization process wherein, in the first stage, a diaryl carbonate and a dihydroxyaromatic compound are reacted together to obtain a polycarbonate oligomer, and then in a second stage, the The polycarbonate oligomers are converted to polycarbonate products. The process employs tetraalkylphosphonium carboxylates as catalysts in the first stage. In the second stage an alkali metal hydroxide is added as a cocatalyst. The process provides a highly end-capped polycarbonate product with a lower Fries product content than other known processes. [0002] Polycarbonate esters are increasingly prepared by melt reaction of diaryl carbonates with dihydroxyaromatic compounds in the presence of transesterification catalysts such as sodium hydroxide. In the "melt" process, the reactants are introduced into a reactor capable of stirring a viscous polycarbonate melt ...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Patents(China)
IPC IPC(8): C08G64/30
CPCC08G64/307C08G64/30
Inventor P·J·麦克罗斯基A·尼索利W·W·赖利
Owner SABIC GLOBAL TECH BV