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
  • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
  • C08G69/46—Post-polymerisation treatment
• • 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
  • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
  • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
  • C08G69/04—Preparatory processes
  • C08G69/06—Solid state polycondensation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/28—Treatment by wave energy or particle radiation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2377/00—Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers

Definitions

• the present invention relates to a process for drying and postcondensation of polyamide particles under irradiation with electromagnetic waves.
• the present invention was therefore based on the object to remedy the aforementioned disadvantages.
• the polyamide particles may be discontinuous or preferably continuously under an inert gas stream at temperatures of 10 to 200 ° C, preferably 15 to 150 ° C, more preferably 18 to 80 ° C, particularly preferably 20 to 40 ° C and a pressure of 0.01 to 10 bar, preferably 0.1 to 7 bar, more preferably 0.9 to 5 bar, in particular at atmospheric pressure (atmospheric pressure) with electromagnetic waves in the range of 300 MHz to 300 GHz, preferably 600 MHz to 50 GHz, more preferably 750 M Hz to 5 GHz, in particular 2.45 GHz (+/- 10%) or 915 MHz (+/- 10%), so-called microwaves, are irradiated.
• the treatment time can be varied within wide limits and is usually 0.1 to 500 h, preferably 0.2 to 50 h, particularly preferably 0.3 to 20 h.
• reaction spaces which are connected to one another or are preferably separated from one another, ie 2 to 10 such as 2, 3, 4, 5, 6, 7, 8, 9 or 10, preferably 2 to 5 as 2, 3, 4 or 5, particularly preferably 2 or 3, in particular 2 reaction spaces, preferably one or 2 reaction spaces.
• reaction spaces in the present invention spaces are referred to, which are present for example in reactors and dryers.
• polyamide particles are suitable in the process according to the invention particles in any form, for example in the form of granules, pellets, grains, spheres, platelets.
• the polyamide particles used in the process according to the invention can be prepared by processes known per se (for example, from EP-B-1 235 671, EP-B-732 351, EP-A-348 821, EP-A-702 047 and EP-A- 284 968). These polyamide particles generally have a content of residual oligomers in the range of 0.3 to 20 wt .-%, preferably 0.35 to 15
• Wt .-% particularly preferably 0.4 to 2.5 wt .-% and a content of residual monomer of less than or equal to 15 wt .-%, that is 0.001 to 15 wt .-%, preferably 0.1 to 12 wt. -%, particularly preferably 8 to 10 wt .-% and humidity of 0.1 to 30 wt .-%, preferably 3 to 15 wt .-% to.
• the size of the polyamide particles can be varied within wide limits and is generally in the diameter 0.1 to 10 mm, preferably 0.2 to 5 mm, more preferably 1 to 4 mm, in particular 2 to 3 mm.
• Polyamides which are suitable are, for example, polyamide-6, polyamide-1 1, polyamide-12, polyamide-7, polyamide-8, polyamide-9, polyamide-10 or copolyamides, and also mixtures of aliphatic and (partially ) aromatic (co) polyamides, preferably polyamide-6 and polyamide-12, more preferably polyamide-6.
• Inert gases are all inert under the process conditions gases such as nitrogen helium, argon, carbon monoxide, carbon dioxide, water vapor or mixtures thereof, preferably nitrogen, carbon monoxide, carbon dioxide and water vapor or mixtures thereof, particularly preferably nitrogen.
• gases such as nitrogen helium, argon, carbon monoxide, carbon dioxide, water vapor or mixtures thereof, preferably nitrogen, carbon monoxide, carbon dioxide and water vapor or mixtures thereof, particularly preferably nitrogen.
• gases such as nitrogen helium, argon, carbon monoxide, carbon dioxide, water vapor or mixtures thereof, preferably nitrogen, carbon monoxide, carbon dioxide and water vapor or mixtures thereof, particularly preferably nitrogen.
• gases such as nitrogen helium, argon, carbon monoxide, carbon dioxide, water vapor or mixtures thereof, preferably nitrogen, carbon monoxide, carbon dioxide and water vapor or mixtures thereof, particularly preferably nitrogen.
• suitable apparatuses are, for example, shafts z. B. with moving bed, fluid
• the active-shaft method which has an additional intrinsic gas circulation, as known from EP-B-1 235 671, paragraphs [0032] to [0037].
• the irradiation may preferably be directly in a - for example, with a window transparent to electromagnetic radiation, z. B. made of quartz or Teflon, provided - drier be performed.
• Suitable dryers are well dryers with an inert gas or steam in countercurrent or direct current, crossflow dryers, fluidized bed dryers or belt dryers.
• the energy required for the process according to the invention can come from 5 to 100%, preferably from 6 to 90%, particularly preferably from 8 to 80%, in particular from 10 to 70%, of electromagnetic energy.
• the inert gas passed through drying and / or aftercondensation can be discarded and is generally preferably directly, more preferably after a complete, ie 100%, or preferably partial, that is to say 5 to 99.9% by volume, preferably 20 to 99.5, particularly preferably 30 to .99.3%, in particular 50 to 99%, are recycled to the process according to the invention.
• the adjustment of the viscosity can be done among other things by temperature control and residence time. As a rule, higher viscosities or higher molecular weights are achieved at higher temperatures.
• the polyamide particles treated according to the invention are suitable for the production of packaging films, fibers, auto parts, electrical and electronic parts and fishing nets.
• Example 1 20.4 l / h of caprolactam melt having a water content of 2 were obtained from a heated pump master at a temperature of 80 ° C. under nitrogen purge at 15 bar pressure % By weight supplied by pump to a heated heat exchanger with an exchange area of 6 m 2 and an inlet temperature of 270 ° C and heated to a temperature of 260 ° C within 2 minutes. The pressure at the pressure side of the pump was 15 bar; the feed was single-phase liquid. The feed solution was pumped continuously through a cylindrical tube of 5000 mm in length and 130 mm in inner diameter filled with 5 mm Raschig Rigged rings with a mean residence time of 2.5 hours.
• the cylindrical tube was heated to 270 ° C with a heat transfer oil.
• the product temperature at the tube end was 270 ° C.
• the pressure at which the reaction mixture was still single-phase liquid was 10 bar.
• the reaction mixture was continuously expanded into a protective heated deposition vessel to 30 atmospheric pressure, the reaction mixture was biphasic and the temperature cooled by adiabatic evaporation of water by 8 ° C to 262 ° C.
• the gaseous vapors consisted of 70% by weight of water and 30% by weight of steam-volatile constituents (the composition was determined by determining the refractive index of the lactam content in the vapor condensate at 25.degree. C., using a calibration curve with different caprolactam / water ratios was) and were discharged at the top of the separation vessel, then liquefied in a condenser and then used for preparation of the preparation.
• the prepolymer was continuously discharged with a melt pump from the separation vessel via a nozzle in a water bath in the form of Schmelzpro- filen, solidified in a water bath and granulated.
• the prepolymer produced in this way was subsequently extracted in countercurrent with water analogously to the prior art (see DD-A 206999) and tempered until a molecular weight of 28500 g / mol had been reached.
• the polyamide-6 granules thus prepared had the following properties:
• REG residual extract content (sum of caprolactam and oligomers)
• VZ viscosity number
• the residual moisture of the polyamide samples was determined in a Karl Fischer apparatus (coulometric determination) (Analytica Chimica Acta, Volume 81, Issue 2, February 1976, pages 231-263).
• the water was expelled at 200 ° C with nitrogen and determined.
• Microwave power power of microwave radiation in watts

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Citations (11)

• 2011
  • 2011-12-14 WO PCT/EP2011/072759 patent/WO2012080335A1/de active Application Filing

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