A method for preparing high-toughness flame-retardant polyphenylene sulfide

Abstract

The present invention discloses a method for preparing high-toughness flame-retardant polyphenylene sulfide, which comprises the following steps: initial treatment: treating polyphenylene sulfide with a polar organic solvent to obtain the initial treated polyphenylene sulfide; re-treatment: treating the initial treated polyphenylene sulfide with an acidic aqueous solution to obtain high-toughness flame-retardant polyphenylene sulfide; the polar organic solvent comprises a ketone solvent, the pH value of the acidic aqueous solution is 5.5-6.5, a first calcium salt is dissolved in the polar organic solvent, a second calcium salt is dissolved in the acidic aqueous solution, and the first calcium salt is selected from an organic calcium salt. The method for preparing high-toughness flame-retardant polyphenylene sulfide provided by the present invention has the effect of improving the heat resistance and toughness of polyphenylene sulfide.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a method for preparing high-toughness flame-retardant polyphenylene sulfide. Background Art

[0002] Polyphenylene sulfide (PPS), also known as polyphenylene sulfide and polyphenylene sulfide, is a semi-crystalline engineering plastic. Due to the special molecular structure, it has many unique properties, including excellent thermal stability, chemical stability, dimensional stability, corrosion resistance, good adhesion, excellent flame retardancy, good electrical properties, and can be blended and modified. It is currently widely used in automobile manufacturing, electronics and electrical, chemical industry, instrumentation and aerospace industry, etc.

[0003] Due to its preparation method, conventional PPS resin will produce a large amount of by-products such as sodium chloride during the synthesis process. These salts are often difficult to completely remove, affecting the insulation properties of PPS products. At the same time, the heat resistance temperature of PPS is relatively low, and a large amount of flame retardant often needs to be added to its products, affecting the mechanical properties of PPS products. Summary of the invention

[0004] In view of the deficiencies of the prior art, the object of the present invention is to provide a method for preparing high-toughness flame-retardant polyphenylene sulfide.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0006] A method for preparing high-toughness flame-retardant polyphenylene sulfide comprises the following steps:

[0007] Primary treatment: treating polyphenylene sulfide with a polar organic solvent to obtain primary treated polyphenylene sulfide;

[0008] Reprocessing: using an acidic aqueous solution to treat the primary polyphenylene sulfide to obtain high-toughness flame-retardant polyphenylene sulfide;

[0009] The polar organic solvent includes a ketone solvent, the pH value of the acidic aqueous solution is 5.5-6.5, a first calcium salt is dissolved in the polar organic solvent, a second calcium salt is dissolved in the acidic aqueous solution, and the first calcium salt is selected from organic calcium salts.

[0010] In the present invention, the ketone solvent has a very strong dissolving ability and can dissolve oligomer impurities to improve the purity of the polyphenylene sulfide system.

[0011] In the present invention, the second calcium salt is dissolved in the acidic aqueous solution, which can reduce the precipitation of the first calcium salt; at the same time, because the second calcium salt is dissolved in the acidic aqueous solution, more calcium ions can be incorporated into the polyphenylene sulfide system, thereby improving the heat resistance and toughness of the polyphenylene sulfide.

[0012] In the present invention, the pH value of the acidic aqueous solution is 5.5-6.5. Under weakly acidic conditions, calcium ions are not easy to precipitate or dissolve from polyphenylene sulfide.

[0013] In the present invention, the pH value of the acidic aqueous solution is specifically 6.0.

[0014] Preferably, the ketone solvent is selected from one or more of acetone, methyl ethyl ketone, butanone, cyclopentanone, cyclohexanone, methyl isobutyl ketone, N-methylpyrrolidone, N-ethylpyrrolidone, N-cyclohexylpyrrolidone and N-hydroxyethylpyrrolidone.

[0015] Preferably, the relative molecular mass of the ketone solvent is ≤85.

[0016] In the present invention, the ketone solvent with a relative molecular mass of ≤85 can more easily penetrate into the polyphenylene sulfide system, thereby improving the swelling effect.

[0017] In the present invention, the ketone solvents are specifically selected from acetone and N-methylpyrrolidone.

[0018] Preferably, the concentration of the first calcium salt dissolved in the polar organic solvent is 3% to 5%.

[0019] Preferably, the concentration of the first calcium salt in the acidic aqueous solution is 1% to 5%.

[0020] Preferably, the first calcium salt is selected from one or more of calcium gluconate and calcium acetate.

[0021] In the present invention, the organic anions of calcium gluconate and calcium acetate can combine with the S atoms in the polyphenylene sulfide system or the oxygen-containing groups on the surface, thereby improving the stability of calcium gluconate and calcium lactate in the polyphenylene sulfide system.

[0022] In the present invention, the first calcium salt is specifically selected from calcium gluconate.

[0023] Preferably, the second calcium salt is selected from one or more of calcium chloride, calcium sulfate, calcium gluconate and calcium acetate.

[0024] In the present invention, the second calcium salt is specifically selected from calcium acetate.

[0025] Preferably, in the initial treatment step, the treatment temperature is 80-120° C. and the treatment time is 2-4 hours.

[0026] In the present invention, in the initial treatment step, the treatment temperature is specifically 100° C., and the treatment time is specifically 2.5 h.

[0027] Preferably, in the initial treatment step, the treatment conditions include ultrasonic treatment.

[0028] Preferably, in the reprocessing step, the processing temperature is 20 to 40° C. and the processing time is 1 to 2 hours.

[0029] In the present invention, in the reprocessing step, the processing temperature is specifically 25° C., and the processing time is specifically 1.5 h.

[0030] Preferably, in the reprocessing step, the mass ratio of the acidic aqueous solution to the initially treated polyphenylene sulfide is (4-6):1.

[0031] Compared with the prior art, the advantages of the present invention include:

[0032] (1) The present invention provides a method for preparing high-toughness flame-retardant polyphenylene sulfide. Ketone solvents have extremely strong solubility. In the initial treatment, ketone solvents can dissolve oligomer impurities in polyphenylene sulfide. At the same time, ketone solvents can penetrate into the polyphenylene sulfide system to produce a swelling effect, promote the opening of the pores of polyphenylene sulfide and make the polyphenylene sulfide compliant, thereby improving the dissolution capacity of salt in polyphenylene sulfide, which is beneficial to remove salt in the polyphenylene sulfide in the reprocessing step.

[0033] (2) The present invention provides a method for preparing a high-toughness flame-retardant polyphenylene sulfide. After the polyphenylene sulfide swells, the polyphenylene sulfide system is more easily doped with calcium ions. A small amount of calcium ions doped into the polyphenylene sulfide system can improve the heat resistance and toughness of the polyphenylene sulfide.

[0034] (3) The present invention provides a method for preparing a high-toughness flame-retardant polyphenylene sulfide. After the salt is dissolved out of the polyphenylene sulfide system, vacancies appear in the polyphenylene sulfide system, making the polyphenylene sulfide chain easy to bend. Calcium ions can fill the vacancies of sodium ions, which is beneficial to maintaining the mechanical strength of polyphenylene sulfide.

[0035] (4) The present invention provides a method for preparing a high-toughness flame-retardant polyphenylene sulfide, wherein the first calcium salt is an organic calcium salt, and the organic anion can be covalently bonded to the polyphenylene sulfide, thereby improving the stability of the calcium ion in the polyphenylene sulfide system. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to understand the characteristics and effects of the present application, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein have the common meanings understood by those skilled in the art for the present application. In case of conflict, the definitions in this specification shall prevail.

[0037] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present application in any way, that is, the content of the present application can be implemented without being limited by any specific theory or mechanism.

[0038] As used herein, "this application" means "the present invention" or "the present disclosure".

[0039] The use of "one", "an", "a kind" or similar expressions to describe the components and technical features described in this application is merely for the convenience of expression and to provide a general meaning to the scope of this application. Therefore, such description should be understood to include one or at least one, and the singular also includes the plural, unless it is obvious that it refers to another meaning.

[0040] In this document, "or its combination" means "or any combination thereof", and "any one", "any one" means "any one", "any one" or "any one".

[0041] In this article, the terms "comprise", "include", "have", "contain" or any other similar terms are open-ended transitional phrases, which are intended to cover non-exclusive inclusions. For example, a composition or product containing multiple elements is not limited to the elements listed in this article, but may also include other elements that are not explicitly listed but are generally inherent to the composition or product. In addition, unless otherwise explicitly stated, the term "or" refers to an inclusive "or" rather than an exclusive "or". For example, any of the following situations satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), A and B are both true (or exist). In addition, in this article, the interpretation of the terms "comprise", "include", "have", and "contain" should be considered to have been specifically disclosed and simultaneously cover closed transitional phrases such as "consisting of", "consisting of", "the balance is", and "substantially consisting of", "mainly consisting of", "mainly consisting of", "basically containing", "basically consisting of", "basically consisting of", "essentially containing" and other transitional phrases.

[0042] In this article, all features or conditions such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for simplicity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be deemed to have covered and specifically disclosed all possible sub-ranges and individual values ​​within the range (including integers and fractions), especially integer values. For example, the range description of "1.0 to 8.0" or "between 1.0 and 8.0" or "between 1.0 and 8.0" should be deemed to have specifically disclosed all sub-ranges such as 1.0 to 8.0, 1.0 to 7.0, 2.0 to 8.0, 2.0 to 6.0, 3.0 to 6.0, 4.0 to 8.0, 3.0 to 8.0, etc., and should be deemed to cover endpoint values, especially sub-ranges defined by integer values, and should be deemed to have specifically disclosed individual values ​​such as 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, etc. Unless otherwise indicated, the foregoing method of interpretation applies to all contents of the entire application, regardless of whether the scope is broad or not.

[0043] If the quantity, concentration or other numerical value or parameter is expressed as a range, a preferred range (or a better range) or a series of upper and lower limits, it should be understood that all ranges consisting of any pair of the upper limit or preferred value (or a better value) of the range and the lower limit or preferred value (or a better value) of the range have been specifically disclosed herein, regardless of whether these ranges are disclosed separately. In addition, if a numerical range is mentioned herein, unless otherwise specified, the range should include its endpoints and all integers and fractions within the range.

[0044] In this document, numerical values ​​should be understood to have the accuracy of the number of significant digits of the numerical value, provided that the purpose of the invention can be achieved. For example, the number 40.0 should be understood to cover the range of 39.50 to 40.49.

[0045] In this article, for the use of Markush groups or optional terms to describe the features or examples of the present application, those skilled in the art should understand that all subgroups or any individual elements in the Markush group or option list can also be used to describe the present application. For example, if X is described as "selected from the group consisting of X1, X2 and X3", it also means that the claim that X is X1 and the claim that X is X1 and / or X2 and / or X3 have been fully described. Furthermore, for the use of Markush groups or optional terms to describe the features or examples of the present application, those skilled in the art should understand that any combination of subgroups or individual members of all elements in the Markush group or option list can also be used to describe the present application. Accordingly, for example, if X is described as "selected from the group consisting of X1, X2 and X3", and Y is described as "selected from the group consisting of Y1, Y2 and Y3", it means that the claim that X is X1 and / or X2 and / or X3 and Y is Y1 and / or Y2 and / or Y3 has been fully described.

[0046] Unless otherwise specified, in this application, a compound refers to a chemical substance formed by two or more elements connected by chemical bonds, including small molecule compounds and polymer compounds, but not limited thereto. The interpretation of a compound in this article is not limited to a single chemical substance, but can also be interpreted as the same type of chemical substances with the same composition or the same properties.

[0047] If not otherwise specified, in this application, polymer refers to the product formed by monomer polymerization, often including many polymer aggregates, each polymer is composed of many simple structural units repeatedly connected by covalent bonds, and the monomer is a compound of synthetic polymer. Polymers can include homopolymers, copolymers, prepolymers, etc., and are not limited to this. Homopolymers refer to polymers polymerized from a monomer. Copolymers include random copolymers (structures such as -AABABBBAAABBA-), alternating copolymers (structures such as -ABABABAB-), graft copolymers (structures such as -AA (A-BBBB) AA (A-BBBB) AAA-) and block copolymers (structures such as -AAAAA-BBBBBB-AAAAA-), etc. Prepolymers refer to a polymer with a lower molecular weight between the monomer and the final polymer, and the prepolymer contains reactive functional groups that can be further polymerized to obtain a fully cross-linked or hardened higher molecular weight product. Polymers certainly include oligomers, and are not limited to this. Oligomers, also known as low polymers, are polymers composed of 2 to 20 repeating units, usually 2 to 5 repeating units.

[0048] Unless otherwise specified, the "resin" in this application is a customary name for a synthetic polymer, which may include monomers, polymers thereof, combinations of monomers, combinations of polymers thereof, or combinations of monomers and polymers thereof, etc., and is not limited thereto.

[0049] If not otherwise specified, in the present application, modified products include products after modification of reactive functional groups of each resin, products after prepolymerization of each resin with other resins, products after crosslinking of each resin with other resins, products after copolymerization of each resin with other resins, and the like.

[0050] If not otherwise specified, the unsaturated bonds described in the present application refer to reactive unsaturated bonds, such as but not limited to unsaturated double bonds that can undergo cross-linking reactions with other functional groups, such as but not limited to unsaturated carbon-carbon double bonds that can undergo cross-linking reactions with other functional groups.

[0051] The unsaturated carbon-carbon double bonds described in the present application preferably include, but are not limited to, vinyl, vinylbenzyl, (meth)acryloyl, allyl or a combination thereof. Vinyl should include vinyl and vinylidene when interpreted. (Meth)acryloyl should include acryloyl and methacryloyl when interpreted.

[0052] Unless otherwise specified, the hydrocarbon groups described in this application include, but are not limited to, alkyl, alkenyl or alkynyl, and include their various isomers when interpreted. For example, a C1-C6 divalent hydrocarbon group is interpreted to include a C1-C6 divalent straight-chain hydrocarbon group, a C2-C6 divalent branched hydrocarbon group or a C3-C6 divalent cyclic hydrocarbon group. For another example, a propyl group should be interpreted to include n-propyl and isopropyl.

[0053] Unless otherwise specified, in this application, parts by weight represent relative parts by weight in a composition, which may be any weight unit, such as but not limited to kilograms, kilograms, grams, pounds, etc. For example, 100 parts by weight of polyphenylene ether resin may represent 100 kilograms of polyphenylene ether resin or 100 pounds of polyphenylene ether resin.

[0054] It should be understood that the features disclosed in the various embodiments herein may be arbitrarily combined to form the technical solution of the present application, as long as there is no contradiction in the combination of these features.

[0055] The present application will be described below with specific implementations and examples. It should be understood that these specific implementations and examples are merely illustrative and are not intended to limit the scope of the present application and its use.

[0056] Unless otherwise stated, the methods, reagents and conditions used in the following preparation examples, comparative examples and examples are conventional methods, reagents and conditions in the art.

[0057] In the following descriptions:

[0058] Polyphenylene sulfide: density 1.68g / cm³, Izod notched impact strength 30.0kJ / m², flexural strength 224MPa, heat deformation temperature under load 265℃, salt content 122ppm;

[0059] Calcium gluconate: active ingredient content ≥99%, molecular weight 430.37;

[0060] Calcium acetate: active ingredient content ≥99%, molecular weight 158.17;

[0061] Acetone: purity ≥99.8%;

[0062] N-Methylpyrrolidone: purity ≥99.8%.

[0063] Preparation Example 1

[0064] The raw materials used in this preparation example include: calcium gluconate and N-methylpyrrolidone.

[0065] The preparation method of this preparation example comprises: dissolving calcium gluconate in N-methylpyrrolidone at 25° C. to prepare 6 L of 3% calcium gluconate solution, 6 L of 4% calcium gluconate solution, and 6 L of 5% calcium gluconate solution.

[0066] Preparation Example 2

[0067] The raw materials used in this preparation example include: calcium gluconate and acetone.

[0068] The preparation method of this preparation example comprises: dissolving calcium gluconate in acetone at 25° C. to prepare 3 L of a 4% calcium gluconate solution.

[0069] Preparation Example 3

[0070] The raw materials used in this preparation example include: calcium acetate and deionized water.

[0071] The preparation method of this preparation example comprises: dissolving calcium acetate in deionized water at 25° C. to prepare 20 L of 1% calcium acetate solution, 10 L of 3% calcium acetate solution, and 6 L of 5% calcium acetate solution.

[0072] Example 1

[0073] The raw materials used in this example include: 3L of the 3% calcium gluconate solution obtained in Preparation Example 1, 1.5kg of polyphenylene sulfide, and 4L of the 1% calcium acetate solution obtained in Preparation Example 3.

[0074] The preparation method of this embodiment includes:

[0075] S1. Initial treatment: immersing polyphenylene sulfide in a calcium gluconate solution and ultrasonically treating the solution at an ultrasonic frequency of 25 kHz, a treatment temperature of 100° C., and a treatment time of 2.5 h to obtain initially treated polyphenylene sulfide;

[0076] S2. Reprocessing: immerse 1 kg of the initially treated polyphenylene sulfide obtained in step S1 in a calcium acetate solution and adjust the pH to 6.0. The treatment temperature is 25° C. and the treatment time is 1.5 h. Then take it out and dry it at 45° C. to obtain high-toughness flame-retardant polyphenylene sulfide.

[0077] Example 2

[0078] The difference between this example and example 1 is that the calcium gluconate solution used in this example is 3 L of 4% calcium gluconate solution obtained in preparation example 1, and the calcium acetate solution is 5 L of 3% calcium acetate solution obtained in preparation example 3.

[0079] Example 3

[0080] The difference between this example and example 1 is that the calcium gluconate solution used in this example is 3 L of 5% calcium gluconate solution obtained in preparation example 1, and the calcium acetate solution is 6 L of 5% calcium acetate solution obtained in preparation example 3.

[0081] Example 4

[0082] The difference between this example and Example 1 is that the calcium gluconate solution used in this example is 3 L of 4% calcium gluconate solution obtained in Preparation Example 1.

[0083] Example 5

[0084] The difference between this example and Example 1 is that the calcium gluconate solution used in this example is 3 L of 5% calcium gluconate solution obtained in Preparation Example 1.

[0085] Example 6

[0086] The difference between this example and Example 2 is that the calcium gluconate solution used in this example is 3 L of 4% calcium gluconate solution obtained in Preparation Example 2.

[0087] Comparative Example 1

[0088] The raw materials used in this comparative example include: 3 L of N-methylpyrrolidone and 1.5 kg of polyphenylene sulfide.

[0089] The preparation method of this comparative example comprises:

[0090] D1. Initial treatment: immersing polyphenylene sulfide in N-methylpyrrolidone and ultrasonically treating the polyphenylene sulfide at an ultrasonic frequency of 25 kHz, a treatment temperature of 100°C, and a treatment time of 2.5 h to obtain initially treated polyphenylene sulfide;

[0091] D2. Retreatment: 1 kg of the initially treated polyphenylene sulfide obtained in step S1 is immersed in 4 L of deionized water and the pH is adjusted to 6.0. The treatment temperature is 25° C. and the treatment time is 1.5 h. Then the polyphenylene sulfide is taken out and dried at 45° C. to obtain high-toughness flame-retardant polyphenylene sulfide.

[0092] Comparative Example 2

[0093] The raw materials used in this comparative example include: 3 L of N-methylpyrrolidone and 1.5 kg of polyphenylene sulfide.

[0094] The preparation method of this comparative example comprises:

[0095] D1. Initial treatment: immersing polyphenylene sulfide in N-methylpyrrolidone and ultrasonically treating the polyphenylene sulfide at an ultrasonic frequency of 25 kHz, a treatment temperature of 100°C, and a treatment time of 2.5 h to obtain initially treated polyphenylene sulfide;

[0096] D2. Retreatment: 1 kg of the initially treated polyphenylene sulfide obtained in step S1 is immersed in 4 L of deionized water and the pH is adjusted to 6.0. The treatment temperature is 25° C. and the treatment time is 1.5 h. Then the polyphenylene sulfide is taken out and dried at 45° C. to obtain high-toughness flame-retardant polyphenylene sulfide.

[0097] Comparative Example 3

[0098] The raw materials used in this comparative example include: 3L of 3% calcium gluconate solution obtained in Preparation Example 1, 1.5kg of polyphenylene sulfide, and 4L of 1% calcium acetate solution obtained in Preparation Example 3.

[0099] The preparation method of this comparative example comprises:

[0100] D1. Initial treatment: immersing polyphenylene sulfide in calcium gluconate solution and ultrasonically treating the polyphenylene sulfide at an ultrasonic frequency of 25 kHz, a treatment temperature of 100°C, and a treatment time of 2.5 h to obtain initially treated polyphenylene sulfide;

[0101] D2. Reprocessing: 1 kg of the initially treated polyphenylene sulfide obtained in step S1 is immersed in a calcium acetate solution and the pH is adjusted to 6.0. The treatment temperature is 25° C. and the treatment time is 1.5 h. Then the solution is taken out and dried at 45° C. to obtain high-toughness flame-retardant polyphenylene sulfide.

[0102] Comparative Example 4

[0103] The raw materials used in this comparative example include: 3 L of N-methylpyrrolidone, 90 g of calcium carbonate powder, 1.5 kg of polyphenylene sulfide, and 4 L of 1% calcium acetate solution obtained in Preparation Example 3.

[0104] The preparation method of this comparative example comprises:

[0105] D1. Calcium carbonate powder is mixed into N-methylpyrrolidone, and then polyphenylene sulfide is immersed and ultrasonically treated at an ultrasonic frequency of 25 kHz, a treatment temperature of 100°C, and a treatment time of 2.5 h. After filtering and rinsing, the initially treated polyphenylene sulfide is obtained;

[0106] D2. Reprocessing: 1 kg of the initially treated polyphenylene sulfide obtained in step S1 is immersed in a calcium acetate solution and the pH is adjusted to 6.0. The treatment temperature is 25° C. and the treatment time is 1.5 h. Then the solution is taken out and dried at 45° C. to obtain high-toughness flame-retardant polyphenylene sulfide.

[0107] Table 1 Part of the raw materials used in Examples 1 to 6 and Comparative Examples 1 to 4

[0108]

[0109] Performance test: The high-toughness flame-retardant polyphenylene sulfide prepared in Examples 1 to 6 and Comparative Examples 1 to 4 was tested according to the following test items:

[0110] (1) Izod notched impact strength is measured in accordance with GB / T 1843-2008, unit: kJ / m 2 ;

[0111] (2) Bending strength shall be measured in accordance with the provisions of GB / T 9341-2008, unit: MPa;

[0112] (3) Heat deformation temperature is measured under a load of 1.8 MPa in accordance with GB / T 1634.2-2019, unit: °C;

[0113] (4) Accelerated aging test: in accordance with ISO4892.3 "Plastics laboratory light source exposure method Part 3 Fluorescent ultraviolet lamp", the test conditions are as follows: light source: UVA-340, radiation energy: 0.8 (W / m² / nm), test temperature: 90℃; each light exposure is 4 hours, the light is turned off for 1 hour, and the cycle test is 80 hours;

[0114] (5) The sodium content was tested using ICP (inductively coupled plasma atomic emission spectrometry).

[0115] Test results: Table 2 Properties of high toughness flame retardant polyphenylene sulfide prepared in Examples 1 to 6 and Comparative Examples 1 to 4

[0116] Test example <![CDATA[Impact strength / (kJ / m 2 )]]> Bending strength / Mpa Deformation temperature / ℃ Whitening time / h Sodium content / ppm Example 1 31.6 250 255 53 24 Example 2 32.5 259 271 61 25 Example 3 33.4 268 288 68 24 Example 4 31.9 252 259 56 26 Example 5 32.2 257 264 58 24 Example 6 33.7 275 280 76 25 Comparative Example 1 30.2 225 225 44 26 Comparative Example 2 30.9 241 241 49 25 Comparative Example 3 30.4 230 230 46 25 Comparative Example 4 30.6 236 235 47 24

[0117] According to Table 2 above, by comparing Example 1 with Comparative Example 1, it can be seen that the impact strength and deformation temperature of the high-toughness flame-retardant polyphenylene sulfide obtained in Example 1 are better than those in Comparative Example 1. The possible reason is that a small amount of calcium ions added to the polyphenylene sulfide system can improve the heat resistance and toughness of the polyphenylene sulfide.

[0118] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly. It cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, some simple deductions or substitutions can be made without departing from the concept of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing high-toughness flame-retardant polyphenylene sulfide, characterized in that: The steps include: Primary treatment: treating polyphenylene sulfide with a polar organic solvent to obtain primary treated polyphenylene sulfide; Reprocessing: using an acidic aqueous solution to treat the primary treated polyphenylene sulfide to obtain high-toughness flame-retardant polyphenylene sulfide; The polar organic solvent includes a ketone solvent, the pH value of the acidic aqueous solution is 5.5-6.5, a first calcium salt is dissolved in the polar organic solvent, a second calcium salt is dissolved in the acidic aqueous solution, and the first calcium salt is selected from an organic calcium salt; The first calcium salt is selected from one or more of calcium gluconate and calcium lactate; The second calcium salt is selected from one or more of calcium chloride, calcium sulfate, calcium gluconate and calcium acetate.

2. The method for preparing a high-toughness flame-retardant polyphenylene sulfide according to claim 1, characterized in that: The ketone solvent is selected from one or more of acetone, methyl ethyl ketone, butanone, cyclopentanone, cyclohexanone, methyl isobutyl ketone, N-methyl pyrrolidone, N-ethyl pyrrolidone, N-cyclohexyl pyrrolidone and N-hydroxyethyl pyrrolidone.

3. The method for preparing a high-toughness flame-retardant polyphenylene sulfide according to claim 2, characterized in that: The relative molecular mass of the ketone solvent is ≤85.

4. The method for preparing a high-toughness flame-retardant polyphenylene sulfide according to claim 1, characterized in that: The polar organic solvent contains a first calcium salt at a concentration of 3% to 5%; And / or, the first calcium salt concentration in the acidic aqueous solution is 1% to 5%.

5. The method for preparing a high-toughness flame-retardant polyphenylene sulfide according to claim 1, characterized in that: In the initial treatment step, the treatment temperature is 80-120°C and the treatment time is 2-4h; And / or, in the initial treatment step, the treatment conditions include ultrasonic treatment.

6. The method for preparing a high-toughness flame-retardant polyphenylene sulfide according to claim 1, characterized in that: In the reprocessing step, the processing temperature is 20 to 40° C. and the processing time is 1 to 2 hours.

7. The method for preparing a high-toughness flame-retardant polyphenylene sulfide according to claim 1, characterized in that: In the reprocessing step, the mass ratio of the acidic aqueous solution to the initially treated polyphenylene sulfide is (4-6):1.

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