Method for recycling additive lithium chloride in polyphenylene sulfide resin production process

A technology of polyphenylene sulfide resin and production process, which is applied in the field of lithium chloride recycling as an auxiliary agent used in the production process of polyphenylene sulfide resin, and can solve the problems of solvent NMP loss, additives that cannot be reused, and PPS cost increase. , to achieve the effect of improving recovery rate, low requirements for equipment and production environment conditions, and reducing energy consumption

Active Publication Date: 2015-09-02
DUNHUANG XIYU MINING & CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In Chinese patent CN001161423, a solvent and co-solvent recovery technology in the production of polyphenylene sulfide is introduced. This technology uses carbonate to recover the so-called catalyst. The catalyst The recovery is very low, generally between 5~10%wt, and the recovered additives cannot b

Method used

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Examples

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Comparison scheme
Effect test

Embodiment 1

[0024] Embodiment 1 The method for the recycling of auxiliary lithium chloride used in the polyphenylene sulfide resin production process comprises the following steps:

[0025] (1) Polyhydrated sodium sulfide is dissolved in NMP (n-methylpyrrolidone), a solvent 2.5 times its mass, and under the catalysis of the auxiliary agent lithium chloride and caustic soda, the moisture in polyhydrated sodium sulfide is removed by inert gas protection , then add DCB (p-dichlorobenzene) and NMP solution, carry out polymerization reaction in a closed reactor according to the conventional method, and synthesize polyphenylene sulfide resin mixture slurry.

[0026] Among them: DCB (p-dichlorobenzene) is 0.8 times the mass of sodium polyhydrate, and NMP solution is 1 times the mass of sodium polyhydrate.

[0027] ⑵Separate the polyphenylene sulfide resin mixture slurry into solid and liquid with a decanter settling discharge centrifuge, and obtain the polyphenylene sulfide resin product contain...

Embodiment 2

[0036] Embodiment 2 The method for the recycling of auxiliary agent lithium chloride used in the polyphenylene sulfide resin production process comprises the following steps:

[0037] (1) Polyhydrated sodium sulfide is dissolved in the solvent NMP (n-methylpyrrolidone) which is 3.5 times its mass, and under the catalysis of the auxiliary agent lithium chloride and caustic soda, the moisture in the polyhydrated sodium sulfide is removed by inert gas protection , then add DCB (p-dichlorobenzene) and NMP solution, carry out polymerization reaction in a closed reactor according to the conventional method, and synthesize polyphenylene sulfide resin mixture slurry.

[0038] Among them: DCB (p-dichlorobenzene) is 0.85 times the mass of sodium polyhydrate, and NMP solution is 1.5 times the mass of sodium polyhydrate.

[0039] ⑵Separate the polyphenylene sulfide resin mixture slurry into solid and liquid with a decanter settling discharge centrifuge, and obtain the polyphenylene sulfid...

Embodiment 3

[0048] Embodiment 3 The method for the recycling of auxiliary agent lithium chloride used in the polyphenylene sulfide resin production process comprises the following steps:

[0049] (1) Polyhydrated sodium sulfide is dissolved in NMP (n-methylpyrrolidone), a solvent 3.0 times its mass, and under the catalysis of the auxiliary agent lithium chloride and caustic soda, the moisture in polyhydrated sodium sulfide is removed by inert gas protection , then add DCB (p-dichlorobenzene) and NMP solution, carry out polymerization reaction in a closed reactor according to the conventional method, and synthesize polyphenylene sulfide resin mixture slurry.

[0050] Among them: DCB (p-dichlorobenzene) is 0.82 times the mass of sodium polyhydrate, and NMP solution is 1.2 times the mass of sodium polyhydrate.

[0051] ⑵Separate the polyphenylene sulfide resin mixture slurry into solid and liquid with a decanter settling discharge centrifuge, and obtain the polyphenylene sulfide resin produc...

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Abstract

The invention relates to a method for recycling additive lithium chloride in polyphenylene sulfide resin production process. The method includes steps of dissolving waterish sodium sulfide in NMP and removing water in the waterish sodium sulfide in inert gas shielding under the catalytic function of lithium chloride and caustic soda flakes, adding DCB and NMP solution to polymerize, and synthesizing to obtain polyphenylene sulfide resin mixture pulp; separating solid of the polyphenylene sulfide resin from liquid to obtain polyphenylene sulfide resin product containing low polymer, bi-product salt and NMP solution containing lithium chloride respectively; filtering and purifying the NMP solution containing lithium chloride to obtain NMP solution containing 75-85% of lithium chloride; inversely soaking and rinsing the polyphenylene sulfide resin product containing low polymer and the bi-product salt to obtain polyphenylene sulfide resin product containing low polymer, bi-product salt and rinsing liquid respectively; depressurizing, distilling and separating rinsing liquid to obtain NMP salt solution; desalinating the NMP salt solution to obtain NMP solution containing 10-20% of lithium chloride. The method is simple and efficient.

Description

technical field [0001] The invention relates to the technical field of recovery and recycling of organic auxiliary agents, in particular to a method for recycling the auxiliary agent lithium chloride used in the production process of polyphenylene sulfide resin. Background technique [0002] Using sodium sulfide (Na 2 S·H 2 O) and p-dichlorobenzene (P-DCB) as raw materials, in the process of polycondensation production of polyphenylene sulfide (PPS) resin under the action of alkali metal and lithium salt additives, alkali metal and lithium salt are required in the polymerization stage NMP (N-methylpyrrolidone) solution completes the catalysis. Compared with the cost of other raw materials, NMP and lithium salt solvent occupy a considerable price proportion, but the solvent NMP and additives are theoretically not consumed in the production process of PPS , Therefore, whether the solvent NMP and additives can be recovered with a higher recovery rate is the key to reducing th...

Claims

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Application Information

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IPC IPC(8): C08J11/02C08J11/00C08G75/02
Inventor 宋祥会李春雷王锦艳杨宾科胡原周文宋立旺钟俊敏唐耀文周华杨永红
Owner DUNHUANG XIYU MINING & CHEM
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