# US 11,299,589 B2 · Process for preparing a polyamide, a nylon salt to be used therein and a process for making the salt

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- Number: US 11,299,589 B2
- Document ID: US11299589B2
- Status: Granted
- Kind: B2
- Application number: 16/778,822
- Filed: 2020-01-31
- Published: 2020-05-28
- Granted: 2022-04-12
- Earliest claimed: 2014-07-29
- Assignees: Dsm IP Assets B.V.
- Applicants: Dsm IP Assets B.V.
- Inventors: Bas Van Laarhoven; Christiaan Johannes Cornelis Stoelwinder; Mark Helmsing
- Web page: https://patentgrep.com/patent/US11299589B2

## CPC

- C08G 69/30: Solid state polycondensation
- B01J 2/04: in a gaseous medium {(if combined with suspending the material in a gas, e.g. fluidised beds B01J2/16)}
- C07C 51/412: {by conversion of the acids, their salts, esters or anhydrides with the same carboxylic acid part}
- C07C 209/68: from amines, by reactions not involving amino groups, e.g. reduction of unsaturated amines, aromatisation, or substitution of the carbon skeleton
- C08G 69/26: derived from polyamines and polycarboxylic acids
- C08G 69/265: {from at least two different diamines or at least two different dicarboxylic acids}
- C08G 69/28: Preparatory processes
- C08J 3/12: Powdering or granulating
- C08J 2377/06: Polyamides derived from polyamines and polycarboxylic acids (C08J2377/10 takes precedence)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)

## Abstract

Processes for preparing a polyamide, a polyamide material obtained by such processes, a nylon salt to be used therein, and processes for making the nylon salt are disclosed. The processes for preparing the polyamide include a direct solid state polymerization process. The salt used herein is a granulate material, prepared by a process, comprising spraying an aqueous solution comprising a diamine and a dicarboxylic acid dissolved in an aqueous medium, or an aqueous slurry comprising a diammonium dicarboxylate salt dispersed in an aqueous medium directly obtained from such an aqueous solution, onto or in a fluidized bed of diammonium dicarboxylate salt particles, while evaporating the aqueous medium, thereby forming a granulate salt material.

## Claims

### Claim 1

A granulate salt material comprising a diammonium dicarboxylate salt which is a fluidized bed spray granulation product of an aqueous solution or an aqueous slurry comprising a diammonium dicarboxylate salt dissolved or dispersed in an aqueous medium, wherein the salt has the following physical properties:
(a) a particle size distribution with a median particle size (d50) in the range of 200-1000 μm, measured by laser granulometry with the method according to ISO 13320-1 at 20° C., and
(b) a tapped bulk density in the range of 350-750 kg/m3, measured by the method according to ASTM D6393.

### Claim 2 (depends on 1)

The granulate salt material according to claim 1, wherein the salt is obtained by a process comprising the steps of:
(i) spraying of the aqueous solution comprised of a diamine, or a mixture of diamines, and a dicarboxylic acid, or a mixture of dicarboxylic acids dissolved in an aqueous medium, or
(ii) spraying the aqueous slurry comprised of a diammonium dicarboxylate salt dispersed in an aqueous medium directly obtained from an aqueous solution comprising a diamine and a dicarboxylic acid dissolved in an aqueous medium, wherein
the aqueous solution or aqueous slurry is sprayed onto or in a fluidized bed of diammonium dicarboxylate salt particles, and wherein a preheated gaseous medium is led through the fluidized bed while evaporating the aqueous medium thereby forming the granulate salt material.

### Claim 3 (depends on 1)

The granulate salt material according to claim 1, wherein the aqueous medium comprises water and an alcohol, or consists of water.

### Claim 4 (depends on 1)

The granulate salt material according to claim 1, wherein the aqueous solution or aqueous slurry has a salt concentration of at least 5 wt. %, relative to the total weight of the solution or slurry.

### Claim 5 (depends on 2)

The granulate salt material according to claim 2, wherein the aqueous solution or aqueous slurry has a temperature of at least 35° C., the gaseous medium led through the fluidized bed has a temperature of at least 50° C., and the fluidized bed has a temperature of at least 35° C.

### Claim 6 (depends on 2)

The granulate salt material according to claim 2, wherein the process comprises preparing a fluidized bed of precursor particles, wherein the precursor particles are salt particles obtained by spray drying or fine particles obtained by separation in a classification step subsequent to a fluidized bed spray granulation step.

### Claim 7 (depends on 2)

The granulate salt material according to claim 2, wherein off-gas resulting from the gaseous medium led through the fluidized bed is exhausted or recycled and wherein the off-gas is passed through a filter or through a scrubber, or is dried, or any combination thereof, before being exhausted or recycled.

### Claim 8 (depends on 1)

The granulate salt material according to claim 1, wherein the granulate salt material has a particle size distribution with a median particle size (d50) in the range of 200-1000 μm, wherein the particle size distribution is measured with laser granulometry by the method according to ISO 13320-1 at 20° C.

### Claim 9 (depends on 1)

The granulate salt material according to claim 1, wherein the granulate salt material has a residual moisture content of at most 7.5 wt. %, relative to the total weight of the granulate salt material.

### Claim 10 (depends on 2)

The granulate salt material according to claim 2, wherein the diamine comprises an aromatic diamine and/or an aliphatic C2-C10 diamine and the dicarboxylic acid comprises a C4-C10 aliphatic dicarboxylic acid and/or an aromatic dicarboxylic acid.

### Claim 11 (depends on 10)

The granulate salt material according to claim 10, wherein the dicarboxylic acid consists for at least 75 mole % of terephthalic acid, wherein the mole % is relative to the total molar amount of the dicarboxylic acid and/or the diamine consists for at least 75 mole % of 1,6-hexamethylediamine (HMDA) or 1,4-diaminobutane (DAB), or a combination thereof, wherein the mole % is relative to the total molar amount of the diamine.

### Claim 12 (depends on 10)

The granulate salt material according to claim 10, wherein the dicarboxylic acid and the diamine are present in a molar ratio in the range of 0.95:1-1.05:1.