A method for preparing unsaturated polyester resin by degradation of waste pet

Abstract

The application provides a method for preparing unsaturated polyester resin by waste PET degradation, and the method uses ethylene glycol, propylene glycol and 2-methyl-1,3-propanediol as a composite alcoholysis agent, uses metal carboxylate, metal oxide and ionic liquid as a composite catalyst, realizes efficient alcoholysis of the polyester under the joint action of multiple small-molecule polyols and multiple catalysts, removes the catalyst and other impurities remaining in the alcoholysis product through ultrasonic stirring treatment to reduce the influence of the catalyst and other impurities on the performance of the final product, and finally reacts the alcoholysis product with unsaturated acid anhydride to obtain high-strength unsaturated polyester, so that green and efficient recycling of the polyester is realized.

Description

TECHNICAL FIELD

[0001] The application relates to a method for preparing unsaturated polyester resin by degrading waste PET, and belongs to the technical field of recycling of waste materials. BACKGROUND

[0002] With the increasing consumption of plastic products, the amount of waste plastics is also increasing, and how to realize the recycling of plastics is an urgent problem to be solved. As one of the most important plastic materials, polyester has the advantages of no smell, no taste, no toxicity, light weight, high strength, good airtightness, high transparency and the like, and is widely applied to fields of beverage bottles, fibers, films, sheet bases and electrical insulation materials. Traditional polyester chemical recycling methods mainly include methanol alcoholysis, hydrolysis, glycolysis and glycol alcoholysis. However, these methods have many unfavorable factors, such as the organic solvent (such as methanol) used in the reaction process is volatile and pollutes the environment; the reaction conditions are harsh and high temperature and high pressure are needed; and the separation process is complex, that is, the raw material, product and acid-base catalyst medium are not easy to separate.

[0003] Therefore, it is still necessary to develop a green and efficient polyester recycling method. SUMMARY

[0004] In view of the problems existing in the prior art, the application provides a method for preparing unsaturated polyester resin by degrading waste PET, in which ethylene glycol, propylene glycol and 2-methyl-1, 3-propanediol are used as a composite alcoholysis agent, and metal carboxylate, metal oxide and ionic liquid are used as a composite catalyst, so that the polyester is efficiently alcoholized under the joint action of a plurality of small-molecule polyols and a plurality of catalysts, the catalyst and other impurities remaining in the alcoholysis product are removed through ultrasonic stirring treatment to reduce the influence of the catalyst and other impurities on the performance of the final product, and finally the alcoholysis product is reacted with an unsaturated acid anhydride to prepare high-strength unsaturated polyester, thereby realizing green and efficient recycling of the polyester.

[0005] The technical scheme of the application is as follows:

[0006] A method for preparing unsaturated polyester resin by degrading waste PET, comprising the following steps:

[0007] Waste polyester is used as a raw material, and a composite alcoholysis agent and a composite catalyst are added to perform an alcoholysis reaction;

[0008] The composite alcoholysis agent at least includes ethylene glycol, propylene glycol and 2-methyl-1, 3-propanediol, and the composite catalyst at least includes metal carboxylate, metal oxide and ionic liquid;

[0009] The product after the alcoholysis reaction is subjected to ultrasonic stirring treatment;

[0010] The unsaturated acid anhydride is added into the alcoholysis product treated by ultrasonic stirring to perform a polymerization reaction to obtain the unsaturated polyester.

[0011] Further, the usage of each raw material is as follows: 100 parts of waste polyester, 200-300 parts of composite alcoholysis agent, 0.5-1 part of composite catalyst, and 100 parts of unsaturated acid anhydride.

[0012] Further, the alcoholysis reaction temperature is 190-210℃, and the reaction time is 3-4h.

[0013] Further, the polymerization temperature is 190-210℃, and the reaction time is 1.5-2h.

[0014] Further, the ultrasonic power is 100-1500W, the stirring speed is 100-1500rpm, and the treatment time is 1-120min.

[0015] Further, the composite alcoholysis agent comprises ethylene glycol, propylene glycol and 2-methyl-1,3-propanediol with a mass ratio of (1-5):(1-5):(1-5).

[0016] Further, the waste polyester is at least one of polyester blended fiber and PET bottle.

[0017] Further, the unsaturated acid anhydride comprises maleic anhydride.

[0018] Further, the mass ratio of the metal carboxylate, the metal oxide and the ionic liquid is (1-5):(1-5):(1-5); the metal carboxylate comprises at least one of zinc acetate, manganese acetate, iron acetate, copper acetate and bismuth acetate; the metal oxide comprises at least one of antimony trioxide and titanium dioxide; and the ionic liquid comprises at least one of imidazole ionic liquid, pyridine ionic liquid, quaternary ammonium ionic liquid and quaternary phosphonium ionic liquid.

[0019] Further, the composite catalyst comprises zinc acetate, antimony trioxide and imidazole ionic liquid with a mass ratio of (1-5):(1-5):(1-5).

[0020] Therefore, the present application provides the following effects and / or advantages:

[0021] The present application takes ethylene glycol, propylene glycol and 2-methyl-1,3-propanediol as a composite alcoholysis agent, reduces the amount of ethylene glycol, and different alcoholysis agents interact with waste polyesters to accelerate the alcoholysis of polyesters; metal carboxylate, metal oxide and ionic liquid are used as a composite catalyst to realize efficient and controllable alcoholysis reaction and improve the conversion rate of polyesters; the alcoholysis product is subjected to ultrasonic stirring treatment to remove catalyst and other impurities remaining in the product, thereby reducing the influence of the impurities on the performance of the final product; and finally, the alcoholysis product is reacted with an unsaturated acid anhydride to prepare an unsaturated polyester, and the obtained unsaturated polyester has good strength and purity, realizing green and efficient recycling of polyesters.

[0022] It should be understood that the above summary of the application and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the application as claimed. DETAILED DESCRIPTION

[0023] For the convenience of those skilled in the art to understand, the technical solutions of the present application will be further described in the embodiments: it should be understood that, in the present embodiment, the steps mentioned, except for the order specified, can be adjusted according to the actual needs of the order, even can be simultaneously or partially simultaneously executed. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0024] In the present embodiment, for the purposes used herein, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0025] The specific embodiments of the present application are as follows:

[0026] A method for preparing unsaturated polyester resin by degrading waste PET, comprising the following steps:

[0027] In a reaction kettle, 100 parts of waste polyester, 200-300 parts of a composite alcoholysis agent and 0.5-1 part of a composite catalyst are added, the composite alcoholysis agent comprises ethylene glycol, propylene glycol and 2-methyl-1,3-propanediol in a mass ratio of (1-5):(1-5):(1-5), the composite catalyst comprises metal carboxylate, metal oxide and ionic liquid in a mass ratio of (1-5):(1-5):(1-5), the metal carboxylate comprises at least one of zinc acetate, manganese acetate, iron acetate, copper acetate and bismuth acetate, the metal oxide comprises at least one of antimony trioxide and titanium dioxide, and the ionic liquid comprises at least one of imidazole ionic liquid, pyridine ionic liquid, quaternary ammonium ionic liquid and quaternary phosphonium ionic liquid, and the reaction is carried out at 190-210℃ for 3-4h.

[0028] The product after alcoholysis reaction is subjected to ultrasonic stirring treatment, the ultrasonic power is 100-1500W, the stirring speed is 100-1500rpm, and the treatment time is 1-120min.

[0029] 100 parts of unsaturated acid anhydride is added to the alcoholysis product subjected to ultrasonic stirring treatment, and polymerization reaction is carried out at 190-210℃ for 1.5-2h to obtain the unsaturated polyester.

[0030] Example 1:

[0031] A method for preparing unsaturated polyester resin by waste PET degradation, comprising the following steps:

[0032] In a reaction kettle, 100 parts of polyester blended fiber, 50 parts of ethylene glycol, 100 parts of propylene glycol, 100 parts of 2-methyl-1,3-propanediol, 0.2 parts of zinc acetate, 0.2 parts of antimony trioxide and 0.2 parts of [Bmim]Cl are added, and the reaction is carried out at 200℃ for 3h to obtain an alcoholysis product.

[0033] The product after alcoholysis reaction is subjected to ultrasonic stirring treatment, the ultrasonic power is 500W, the stirring speed is 500rpm, and the treatment time is 60min.

[0034] 100 parts of unsaturated acid anhydride is added to the alcoholysis product subjected to ultrasonic stirring treatment, and polymerization reaction is carried out at 200℃ for 2h to obtain unsaturated polyester, and the finished product is obtained through filtration, washing, crystallization and drying treatment.

[0035] The conversion rate of the alcoholysis reaction is 99.8%, the purity of the unsaturated polyester is 99.3%, the unsaturated polyester is formed into a polyester film, the tensile strength of the film is 158MPa, and the bending strength is 262MPa.

[0036] Example 2:

[0037] Compared with example 1, the difference lies in that the antimony trioxide is replaced by titanium dioxide.

[0038] An unsaturated polyester was produced in the same manner as in Example 1. The alcoholysis reaction conversion rate was 99.5%, the unsaturated polyester purity was 98.5%, the unsaturated polyester was formed into a polyester film, the film tensile strength was 153 MPa, and the film flexural strength was 256 MPa.

[0039] Example 3:

[0040] The difference from Example 1 was that the [Bmim]Cl was replaced with 1- ethylpyridinium hydrochloride.

[0041] An unsaturated polyester was produced in the same manner as in Example 1. The alcoholysis reaction conversion rate was 99.3%, the unsaturated polyester purity was 98.3%, the unsaturated polyester was formed into a polyester film, the film tensile strength was 149 MPa, and the film flexural strength was 252 MPa.

[0042] Comparative Example 1:

[0043] The difference from Example 1 was that 2-methyl-1,3-propanediol was not added, and instead 100 parts of ethylene glycol and 150 parts of propylene glycol were used.

[0044] An unsaturated polyester was produced in the same manner as in Example 1. The alcoholysis reaction conversion rate was 87.5%, the unsaturated polyester purity was 86.4%, the unsaturated polyester was formed into a polyester film, the film tensile strength was 118 MPa, and the film flexural strength was 204 MPa.

[0045] When only ethylene glycol and propylene glycol were used as the alcoholysis agent, the alcoholysis conversion rate decreased, the product purity was low, and the strength of the resulting film decreased.

[0046] Comparative Example 2:

[0047] The difference from Example 1 was that ethylene glycol was not added, and instead 125 parts of propylene glycol and 125 parts of 2-methyl-1,3-propanediol were used.

[0048] An unsaturated polyester was produced in the same manner as in Example 1. The alcoholysis reaction conversion rate was 84.6%, the unsaturated polyester purity was 84.5%, the unsaturated polyester was formed into a polyester film, the film tensile strength was 106 MPa, and the film flexural strength was 192 MPa.

[0049] When only propylene glycol and 2-methyl-1,3-propanediol were used as the alcoholysis agent, the alcoholysis conversion rate decreased, the product purity was low, and the strength of the resulting film decreased.

[0050] Comparative Example 3:

[0051] The difference from Example 1 was that propylene glycol was not added, and instead 100 parts of ethylene glycol and 150 parts of 2-methyl-1,3-propanediol were used.

[0052] An unsaturated polyester was produced in the same manner as in Example 1. The alcoholysis conversion rate was 85.8%, the purity of the unsaturated polyester was 85.6%, the unsaturated polyester was formed into a polyester film, the tensile strength of the film was 112 MPa, and the flexural strength was 198 MPa.

[0053] When only ethylene glycol and 2-methyl-1,3-propanediol were used as the alcoholysis agent, the alcoholysis conversion rate was low, the purity of the product was low, and the strength of the resulting film was low.

[0054] Comparative Example 4:

[0055] The difference from Example 1 was that only 250 parts of ethylene glycol was used as the alcoholysis agent.

[0056] An unsaturated polyester was produced in the same manner as in Example 1. The alcoholysis conversion rate was 68.5%, the purity of the unsaturated polyester was 70.2%, the unsaturated polyester was formed into a polyester film, the tensile strength of the film was 78 MPa, and the flexural strength was 162 MPa.

[0057] The alcoholysis efficiency of ethylene glycol alone was low, and the performance of the resulting product was significantly deteriorated.

[0058] Comparative Example 5:

[0059] The difference from Example 1 was that the stirring operation was not performed.

[0060] An unsaturated polyester was produced in the same manner as in Example 1. The purity of the unsaturated polyester was 94.2%, the unsaturated polyester was formed into a polyester film, the tensile strength of the film was 132 MPa, and the flexural strength was 234 MPa.

[0061] Only ultrasonic treatment was performed, and the impurities were not effectively removed, the purity of the resulting product was low, and the strength was low.

[0062] Comparative Example 6:

[0063] The difference from Example 1 was that the stirring operation was not performed.

[0064] An unsaturated polyester was produced in the same manner as in Example 1. The purity of the unsaturated polyester was 92.3%, the unsaturated polyester was formed into a polyester film, the tensile strength of the film was 126 MPa, and the flexural strength was 228 MPa.

[0065] Only the stirring treatment was performed, and the impurities were not effectively removed, the purity of the resulting product was low, and the strength was low.

[0066] Comparative Example 7:

[0067] The difference from Example 1 was that the ultrasonic stirring treatment was not performed.

[0068] An unsaturated polyester was produced in the same manner as in Example 1. The unsaturated polyester had a purity of 88.2%, and the unsaturated polyester was formed into a polyester film having a tensile strength of 121 MPa and a flexural strength of 208 MPa.

[0069] Comparative Example 8:

[0070] Comparative Example 1 was modified by not adding [Bmim]Cl, and instead using 0.3 parts of zinc acetate and 0.3 parts of antimony trioxide.

[0071] An unsaturated polyester was produced in the same manner as in Example 1. The alcoholysis reaction conversion rate was 78.6%, the unsaturated polyester had a purity of 78.5%, and the unsaturated polyester was formed into a polyester film having a tensile strength of 98 MPa and a flexural strength of 182 MPa.

[0072] Using only zinc acetate and antimony trioxide as catalysts, efficient alcoholysis was not achieved, the alcoholysis conversion rate was low, the product purity was low, and the resulting film strength was low.

[0073] Comparative Example 9:

[0074] Comparative Example 1 was modified by not adding zinc acetate, and instead using 0.3 parts of [Bmim]Cl and 0.3 parts of antimony trioxide.

[0075] An unsaturated polyester was produced in the same manner as in Example 1. The alcoholysis reaction conversion rate was 77.7%, the unsaturated polyester had a purity of 77.4%, and the unsaturated polyester was formed into a polyester film having a tensile strength of 92 MPa and a flexural strength of 173 MPa.

[0076] Using only [Bmim]Cl and antimony trioxide as catalysts, efficient alcoholysis was not achieved, the alcoholysis conversion rate was low, the product purity was low, and the resulting film strength was low.

[0077] Comparative Example 10:

[0078] Comparative Example 1 was modified by not adding antimony trioxide, and instead using 0.3 parts of zinc acetate and 0.3 parts of [Bmim]Cl.

[0079] An unsaturated polyester was produced in the same manner as in Example 1. The alcoholysis reaction conversion rate was 78.2%, the unsaturated polyester had a purity of 77.8%, and the unsaturated polyester was formed into a polyester film having a tensile strength of 95 MPa and a flexural strength of 178 MPa.

[0080] Using only zinc acetate and [Bmim]Cl as catalysts, efficient alcoholysis was not achieved, the alcoholysis conversion rate was low, the product purity was low, and the resulting film strength was low.

[0081] Comparative Example 11:

[0082] The difference from Example 1 is that only 0.6 parts of zinc acetate is used as a catalyst.

[0083] The unsaturated polyester is prepared in the same manner as in Example 1. The alcoholysis reaction conversion rate is 65.4%, the unsaturated polyester purity is 66.3%, the unsaturated polyester is formed into a polyester film, the film tensile strength is 65 MPa, and the film bending strength is 151 MPa.

[0084] The catalytic efficiency of only zinc acetate as a catalyst is very low, and the performance of the product is significantly deteriorated.

[0085] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. The present application can be variously changed and modified by those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing unsaturated polyester resin by degrading waste PET, characterized in that, Includes the following steps: Waste polyester was used as raw material, and a composite alcoholysis agent and a composite catalyst were added to carry out an alcoholysis reaction; The composite alcoholysis agent includes at least ethylene glycol, propylene glycol and 2-methyl-1,3-propanediol, and the composite catalyst includes at least a metal carboxylate, a metal oxide and an ionic liquid. The product after alcoholysis reaction was subjected to ultrasonic stirring. Unsaturated acid anhydride is added to the alcoholysis product after ultrasonic stirring to carry out a polymerization reaction, thereby obtaining the unsaturated polyester. The composite alcoholysis agent comprises ethylene glycol, propylene glycol, and 2-methyl-1,3-propanediol in a mass ratio of (1-5):(1-5):(1-5); The mass ratio of the metal carboxylate, metal oxide, and ionic liquid is (1-5):(1-5):(1-5); the metal carboxylate includes at least one of zinc acetate, manganese acetate, ferric acetate, copper acetate, and bismuth acetate; the metal oxide includes at least one of antimony trioxide and titanium dioxide; and the ionic liquid includes at least one of imidazole ionic liquid, pyridine ionic liquid, quaternary ammonium ionic liquid, and quaternary phosphorus ionic liquid. The composite catalyst comprises zinc acetate, antimony trioxide, and imidazole ionic liquid in a mass ratio of (1-5):(1-5):(1-5); The amounts of each raw material are as follows: 100 parts waste polyester, 200-300 parts composite alcoholysis agent, 0.5-1 part composite catalyst, and 100 parts unsaturated acid anhydride. The alcoholysis reaction temperature is 190-210℃, and the reaction time is 3-4 hours.

2. The method for preparing unsaturated polyester resin by degrading waste PET according to claim 1, characterized in that: The polymerization temperature is 190-210℃, and the reaction time is 1.5-2h.

3. The method for preparing unsaturated polyester resin by degrading waste PET according to claim 1, characterized in that: The ultrasonic power is 100-1500W, the stirring speed is 100-1500rpm, and the processing time is 1-120min.

4. The method for preparing unsaturated polyester resin by degrading waste PET according to claim 1, characterized in that: The waste polyester is at least one of polyester blended fibers and PET bottles.

5. The method for preparing unsaturated polyester resin by degrading waste PET according to claim 1, characterized in that: The unsaturated anhydride includes maleic anhydride.