Ionic liquid flame-retardant plastic part as well as preparation and application thereof

Abstract

The invention belongs to the field of composite materials, and discloses a flame-retardant plastic part as well as preparation and application thereof. The preparation method of the flame-retardant plastic part comprises the following steps: 1) carrying out twin-screw extrusion granulation, and preparing plastic particles comprising the following components in percentage by weight: 52-98.5% of resin; 0.5%-5% of an ionic liquid flame retardant; 1-5% of an ionic liquid synergist; 0%-30% of glass fiber; 0%-1% of an antioxidant; 0%-1% of a release agent; 0-6% of a toughening agent; 2) processing and forming the plastic particles into a required workpiece; 3) treating the plastic part at a temperature higher than Tg of the plastic and a direct-current voltage; and 4) cooling to room temperature, and removing the electric field to obtain the plastic part. According to the flame-retardant plastic product disclosed by the invention, a relatively high flame-retardant grade can be realized for plastic products in different wall thickness ranges under the condition that a very small amount of flame retardant is added.

Description

Technical Field

[0001] The invention belongs to the field of composite materials, and particularly relates to an ionic liquid flame retardant plastic part and a preparation method and application thereof. Background Art

[0002] Flame-retardant plastic parts are an important type of plastic products, especially in the field of engineering plastics, where flame-retardant products account for about half of the market applications. With the gradual improvement of safety regulations in various countries, the requirements for flame retardancy levels in various application fields are getting higher and higher. Conventional flame retardant technology mainly involves adding halogen flame retardants or phosphorus flame retardants. A major disadvantage is that the amount added is large, which will significantly affect other comprehensive properties of plastic products. At the same time, halogen flame retardancy is restricted in more and more fields due to environmental unfriendliness. In order to reduce the amount of flame retardants used, one method is to use surface coating or spraying methods to enrich the flame retardant on the surface of plastic products. However, this requires secondary processing, which greatly increases costs, and it is also difficult to ensure the stability of surface flame retardants. There is no mature technology yet.

[0003] Ionic liquid flame retardants are a new type of flame retardant that has emerged in recent years. Ionic liquids themselves are organic compounds with good compatibility with plastics. By designing ionic liquids with different chemical structures, the structure of ionic liquids contains flame retardant elements such as phosphorus, fluorine, and nitrogen, which can make ionic liquids have flame retardant effects. However, the current disadvantages of ionic liquid flame retardants are mainly insufficient flame retardant efficiency and high prices. If the amount added is large, it will play a role similar to that of plasticizers, reduce the mechanical properties of plastics, and greatly increase costs. The anions and cations in ionic liquids can move under the action of an electric field. If the migration characteristics of ionic liquids in an electric field can be used to enrich ionic liquids on the surface of plastic products, the flame retardant efficiency of ionic liquids can be greatly improved. Patent application publication CN202411364512.6 records a method for achieving flame retardancy of plastic products by utilizing the migration characteristics of ionic liquids in an electric field. However, this method can only achieve flame retardancy of thinner plastic products, and when the wall thickness of the product is large, it cannot achieve a good flame retardant effect. Summary of the invention

[0004] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide an ionic liquid flame-retardant plastic part. The plastic part uses ionic liquid as a flame retardant, uses a small amount of flame retardant, has low cost, and can achieve a higher flame retardant grade of the sample within a wider range of wall thickness.

[0005] Another object of the present invention is to provide an ionic liquid flame-retardant plastic product prepared by the above method.

[0006] Another object of the present invention is to provide applications of the above-mentioned ionic liquid flame-retardant plastic parts.

[0007] The purpose of the present invention is achieved through the following solutions:

[0008] A method for preparing an ionic liquid flame-retardant plastic part comprises the following steps:

[0009] 1) preparing plastic particles comprising the following components in percentage by weight by twin-screw extrusion granulation:

[0010]

[0011] 2) Processing the plastic particles into the required parts;

[0012] 3) Treating plastic parts at a temperature higher than the Tg of the plastic and a DC voltage, the ionic liquid migrates to the surface of the plastic parts under the action of the electric field and is enriched;

[0013] 4) After cooling to room temperature, the electric field is removed to obtain the plastic product.

[0014] The resin described in step (1) includes at least one of polycarbonate, polyamide, polybutylene terephthalate (PBT), and polyethylene terephthalate (PET).

[0015] The ionic liquid flame retardant described in step (1) includes at least one of imidazole ionic liquids, pyrrolidine ionic liquids, quaternary ammonium salt ionic liquids, piperidine ionic liquids, and pyridine ionic liquids, preferably at least one of 1,3-dimethylimidazolium methanesulfonate ([C1MIm]MS), 1-ethylpyridinium hexafluorophosphate ([C2Py]PF6), and 1-ethyl-1-methylpiperidinium p-toluenesulfonate ([C2MPd]TS).

[0016] The ionic liquid synergist described in step (1) includes one of epoxy linseed oil and N-butylbenzenesulfonamide or a mixture thereof.

[0017] When the resin described in step (1) is mainly polybutylene terephthalate (PBT), especially when the resin is a single polybutylene terephthalate (PBT), the ionic liquid synergist is preferably epoxy linseed oil, and the weight percentage of the epoxy linseed oil is 1-2%. The resin mainly being polybutylene terephthalate (PBT) means that the resin contains at least polybutylene terephthalate (PBT), and the mass of the polybutylene terephthalate (PBT) in the resin is the largest.

[0018] When the resin in step (1) is mainly polycarbonate, especially when the resin is a single polycarbonate, the ionic liquid synergist is preferably epoxy linseed oil, and the weight percentage of the epoxy linseed oil is 3-5%. The resin being mainly polycarbonate means that the resin contains at least polycarbonate, and the mass of the polycarbonate in the resin is the largest.

[0019] When the resin in step (1) is mainly polyamide, especially when the resin is a single polyamide, the ionic liquid synergist is preferably N-butylbenzenesulfonamide, and the weight percentage of N-butylbenzenesulfonamide is 1-3%. The resin being mainly polyamide means that the resin contains at least polyamide, and the mass of the polyamide in the resin is the largest.

[0020] The antioxidant described in step (1) is at least one of a hindered phenol antioxidant, a hindered amine antioxidant, and a phosphite antioxidant;

[0021] The release agent described in step (1) is at least one of a fatty acid salt and a fatty acid ester, preferably pentaerythritol stearate PETS;

[0022] The toughening agent described in step (1) is at least one of polyolefin, polyacrylate copolymer and polybutadiene copolymer, preferably the toughening agent MBS.

[0023] The processing and molding described in step (2) is preferably performed by injection molding or extrusion molding, and the ionic liquid flame retardant will be evenly dispersed in the plastic part.

[0024] The plastic part described in step (2) is a flat plate part with a thickness of 0.2-2 mm, preferably 1-2 mm.

[0025] The DC voltage described in step (3) is 10-200V; the processing time is 1min-60min; the positive and negative electrodes of the DC current are both electrode plates, which are in direct contact with the two sides of the plastic component respectively, and the contact surface covers the entire surface of the component, thereby ensuring that all ionic liquids in the plastic component can move under the action of the electric field.

[0026] When the resin described in step (1) is a crystalline polymer, the temperature described in step (3) is preferably higher than the Tg of the plastic and lower than the Tm of the resin; when the resin in step (1) is an amorphous polymer, the temperature described in step (3) is preferably higher than the Tg of the plastic and lower than the Tf of the resin.

[0027] In step (4), since the temperature is lowered to below the Tg of the plastic, the ionic liquid will be fixed near the surface of the plastic part, achieving a higher flame retardant efficiency than uniform distribution.

[0028] An ionic liquid flame-retardant plastic product prepared by the method.

[0029] The above-mentioned ionic liquid flame-retardant plastic parts are used in automobiles, electronic appliances or consumer electronic products.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] The flame retardant plastic product of the present invention can achieve a high flame retardant grade for plastic products within different wall thickness ranges when very little flame retardant is added. Meanwhile, the preparation method of the present invention is simple and easy to implement, and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of electrical treatment of plastic parts. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with the examples and drawings, but the embodiments of the present invention are not limited thereto. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0034] The technical solution of the present application is described in detail using an embodiment below. The raw materials in the embodiment can all be obtained commercially, as follows: PBT is Changchun Chemical 1100-211S, polycarbonate PC is SABIC Lexan 141R, polyamide 66 is BASF Ultramid A3L, ionic liquid 1,3-dimethylimidazole methanesulfonate ([C1MIm]MS), 1-ethylpyridinium hexafluorophosphate ([C2Py]PF6), 1-ethyl-1-methylpiperidinium p-toluenesulfonate ([C2MPd]TS) are all purchased from Merck, epoxidized linseed oil is purchased from Zhejiang Xingbang Polymer Materials Co., Ltd., and N-butylbenzenesulfonamide is purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd. The flame retardant test refers to UL94 standard. The tensile strength test refers to ISO527, and the impact strength test refers to ISO179.

[0035] Examples 1-5

[0036] The flame retardant plastic parts are prepared by the following steps:

[0037] (1) Through twin-screw extrusion processing, the processing temperature is 230-260° C., preparing plastic particles comprising the following components in percentage by weight:

[0038] Table 1. Raw materials and weight percentage of flame retardant plastic parts in Comparative Example 1 and Examples 1-5

[0039] Weight percentage (%) Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 PBT 94.7 93.7 92.7 91.7 90.7 89.7 [C1MIm]MS 5 5 5 5 5 5 1010 0.1 0.1 0.1 0.1 0.1 0.1 PETS 0.2 0.2 0.2 0.2 0.2 0.2 Epoxidized linseed oil 1 2 3 4 5

[0040] 2) The obtained plastic particles were processed into UL94 flame retardant strips with thicknesses of 0.8 mm, 1.2 mm, 1.6 mm, 2.0 mm, and 4 mm by injection molding at an injection molding temperature of 260° C. and a mold temperature of 50° C.

[0041] 3) Treat the workpiece at 120°C and 30V DC voltage for 5 minutes.

[0042] 4) Remove the electric field after cooling naturally to room temperature. Test the flame retardant grade, tensile strength and notched impact strength of the sample.

[0043] Table 2. Performance data of Comparative Example 1 and Examples 1-5

[0044]

[0045] Embodiment 6-11

[0046] The flame retardant plastic parts are prepared by the following steps:

[0047] (1) Through twin-screw extrusion processing, the processing temperature is 250-290° C., preparing plastic particles comprising the following components in weight percentage:

[0048] Table 3. Raw materials and weight percentage of flame retardant plastic parts in Comparative Example 2 and Examples 6-11

[0049]

[0050] 2) The obtained plastic particles were molded into UL94 flame retardant strips with thicknesses of 0.4 mm, 0.8 mm, 1.2 mm, 2.0 mm, and 4 mm by injection molding at an injection molding temperature of 300° C. and a mold temperature of 80° C.

[0051] 3) Treat the workpiece at 170°C and 100 V DC voltage for 2 min.

[0052] 4) Remove the electric field after cooling naturally to room temperature. Test the flame retardant grade and tensile strength of the sample.

[0053] Table 4 Performance data of comparative example 2 and examples 6-11

[0054]

[0055] Examples 12-16

[0056] The flame retardant plastic parts are prepared by the following steps:

[0057] 1) Through twin-screw extrusion processing, the processing temperature is 250-280° C., preparing plastic particles including the following components in weight percentage:

[0058] Table 5. Raw materials and weight percentage of flame retardant plastic parts in Comparative Example 3 and Examples 12-16

[0059]

[0060] 2) The obtained plastic particles were molded into UL94 flame retardant strips with thicknesses of 0.8 mm, 1.2 mm, 1.6 mm, 2.0 mm, and 4 mm by injection molding at an injection molding temperature of 280° C. and a mold temperature of 60° C.

[0061] 3) Treat the workpiece at 140°C and 50V DC voltage for 5 minutes.

[0062] 4) Remove the electric field after cooling naturally to room temperature. Test the flame retardant grade and tensile strength of the sample.

[0063] Table 6. Performance data of Comparative Example 3 and Examples 12-16

[0064]

[0065] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing an ionic liquid flame-retardant plastic part, characterized in that The following steps are involved: 1) preparing plastic particles comprising the following components in percentage by weight by twin-screw extrusion granulation: 2) Processing the plastic particles into the required parts; 3) Treating plastic parts at a temperature higher than the Tg of the plastic and a DC voltage, the ionic liquid migrates to the surface of the plastic parts under the action of the electric field and is enriched; 4) After cooling to room temperature, the electric field is removed to obtain the plastic product.

2. The method for preparing an ionic liquid flame-retardant plastic product according to claim 1, characterized in that: The resin described in step (1) includes at least one of polycarbonate, polyamide, polybutylene terephthalate and polyethylene terephthalate.

3. The method for preparing an ionic liquid flame-retardant plastic product according to claim 1, characterized in that: The ionic liquid flame retardant described in step (1) includes at least one of imidazole ionic liquids, pyrrolidine ionic liquids, quaternary ammonium salt ionic liquids, piperidine ionic liquids, and pyridine ionic liquids, preferably at least one of 1,3-dimethylimidazolium methanesulfonate, 1-ethylpyridinium hexafluorophosphate, and 1-ethyl-1-methylpiperidinium p-toluenesulfonate.

4. The method for preparing an ionic liquid flame-retardant plastic product according to claim 1, characterized in that: The ionic liquid synergist described in step (1) includes at least one of epoxy linseed oil and N-butylbenzenesulfonamide.

5. The method for preparing an ionic liquid flame-retardant plastic product according to claim 1, characterized in that: The antioxidant described in step (1) is at least one of a hindered phenol antioxidant, a hindered amine antioxidant, and a phosphite antioxidant; The release agent described in step (1) is at least one of a fatty acid salt and a fatty acid ester, preferably pentaerythritol stearate PETS; The toughening agent described in step (1) is at least one of polyolefin, polyacrylate copolymer and polybutadiene copolymer, preferably the toughening agent MBS.

6. The method for preparing an ionic liquid flame-retardant plastic product according to claim 1, characterized in that: The plastic part described in step (2) is a flat plate part with a thickness of 0.2-2 mm, preferably 1-2 mm.

7. The method for preparing an ionic liquid flame-retardant plastic product according to claim 1, characterized in that: The DC voltage in step (3) is 10-200V; the treatment time is 1min-60min.

8. The method for preparing an ionic liquid flame-retardant plastic product according to claim 1, characterized in that: When the resin described in step (1) is a crystalline polymer, the temperature described in step (3) is higher than the Tg of the plastic and lower than the Tm of the resin; when the resin in step (1) is an amorphous polymer, the temperature described in step (3) is higher than the Tg of the plastic and lower than the Tf of the resin.

9. An ionic liquid flame-retardant plastic product prepared by the method according to any one of claims 1 to 8.

10. Use of the ionic liquid flame-retardant plastic parts according to claim 9 in automobiles, electronic appliances, and consumer electronic products.

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