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Continuous polymerization process for preparing polyamides from omega-aminonitriles

A technology of polyamide and aminonitrile, which is applied in the field of polyamide preparation, and can solve problems such as inconsistency between batches of products, uneven final products, and high labor intensity

Inactive Publication Date: 2001-11-28
INVISTA TECHNOLOG IES S A R L
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Most of the processes disclosed in the art are batch-wise, with potential disadvantages associated with this approach being labor-intensive to operate, non-uniform final product in each batch, and batch-to-batch inconsistency

Method used

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  • Continuous polymerization process for preparing polyamides from omega-aminonitriles
  • Continuous polymerization process for preparing polyamides from omega-aminonitriles
  • Continuous polymerization process for preparing polyamides from omega-aminonitriles

Examples

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Embodiment 1

[0054] A liquid mixture consisting of 90% by weight of 6-aminocapronitrile and 10% by weight of water and containing 0.1% by weight of phosphoric acid based on the final polymer is heated at about room temperature at about 40 pounds per hour. The rate was fed continuously to the top of an 8 inch diameter vertical reactor. The reactor is about 20 feet high. The reactor is divided into eleven stages by using horizontal perforated partitions to separate each stage from the stage above and below it. These partitions consist of a circular plate 1 / 8-3 / 8 inch thick with 6-16 1 / 8 inch diameter holes drilled in a 4 and 6 inch diameter perforated ring for vapor channel, and equipped with one or three downcomers as liquid channels. These dividers are positioned at 18 inch intervals. All downcomers are 8 inches long to allow them to extend below the surface of the liquid in the next stage. Where the bulkhead has one downcomer, the downcomer has an inside diameter of 2.25 inches and is...

Embodiment 2

[0058] A liquid mixture consisting of 90% by weight 6-aminocapronitrile and 10% by weight water and containing 0.1% by weight phosphoric acid was fed continuously to Example 1 at a rate of about 56 pounds per hour at about room temperature. The top section of the reactor described in . The temperature of the reactor was controlled so that the top stage was at 210°C and the bottom stage was at 278°C. Saturated steam at a temperature of 220-230°C was continuously fed into the upper portion of each of the bottom four stages at a total flow rate of about 51 pounds per hour. The pressure in the vessel was maintained at 250 psig. The liquid exiting the bottom of the vessel was analyzed and found to have an equivalent carboxyl content of about 206 grams per million grams of sample, an amine end group content of about 196, and a relative viscosity of about 7.2 for the unextracted polymer. The liquid was passed continuously through the pipeline and the container at 0 psig as describe...

Embodiment 3

[0060] A liquid mixture consisting of 90% by weight 6-aminocapronitrile and 10% by weight water and containing 0.1% by weight phosphoric acid was fed continuously to Example 1 at a rate of about 37 pounds per hour at about room temperature. The top section of the reactor described in . The temperature of the reactor was controlled so that the top stage was at 213°C and the bottom stage was at 281°C. Saturated steam at a temperature of 220-230°C was continuously fed into the upper portion of each of the three stages immediately above the bottom section at a total flow rate of about 54 pounds per hour. The pressure in the vessel was maintained at 250 psig. Nitrogen was continuously fed into the upper portion of the bottoms section at a flow rate of 12 pounds per hour. The liquid exiting the bottom of the vessel was analyzed to have a carboxyl content of approximately 86 gram equivalents per million gram samples, 4.3 gram equivalents per million gram samples of IBHA, approximat...

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Abstract

A continuous process for the polymerization of omega-aminonitriles (e.g., 6-aminocapronitriles) which is introduced at the top of a vertical multistage reactor being swept countercurrently with steam and polyamide (e.g., nylon 6) is recovered near the bottom of the vertical multistage reactor. By virtue of independent temperature control at each of the vertical stages of the multistage reactor, the polyamide recovered is typicaly characterized as having unreacted nitrile end groups of less than 20 gram equivalents per million grams of polyamide, and less than 25 gram equivalents of secondary amine branching per million grams of polyamide.

Description

[0001] Applicants claim the benefit of priority of provisional application 60 / 105,656, filed October 26,1998. technical field [0002] The present invention relates to a process for the preparation of polyamides. More specifically, the present invention relates to a continuous process for the preparation of polyamides by reaction of ω-aminonitriles in a countercurrent multistage reactor purged with steam. Background technique [0003] Polyamides are conveniently prepared by polycondensation of diacids, such as adipic acid, and diamines, such as hexamethylenediamine, or by polymerization of lactams, such as ε-caprolactam. Other methods for the preparation of polyamides involving the reaction of omega-aminonitriles with water are well known. For example, US Patent 2,245,129 to Greenwalt discloses the preparation of polyamides by heating ω-aminonitriles in the presence of water in a two-step process. In the first step, the react...

Claims

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Application Information

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IPC IPC(8): C08G69/04C08G69/16
CPCC08G69/16C08G69/04B29B7/002B29B7/826
Inventor E·K·马赤尔顿A·T·穆特尔
Owner INVISTA TECHNOLOG IES S A R L