Modified polyester composition and manufacturing method thereof

Abstract

The invention relates to a modified polyester composition, which comprises modified polyester and a filling material. The modified polyester comprises a polyester material, a nucleating agent and an antioxidant. And the polyester material comprises macromolecules of polyethylene terephthalate. The content of the nucleating agent in the modified polyester is 0.5 wt% to 3 wt%.

Description

Technical Field

[0001] The invention relates to a modified polyester composition and a preparation method thereof. Background Art

[0002] With the improvement of environmental awareness, the recycling of plastic products has received increasing attention. At present, many clothes use polyethylene terephthalate (PET) as the fiber material in the production process, and are equipped with zippers or buttons made of polyoxymethylene (POM) or nylon. However, since PET and POM or nylon are different plastics, zippers or buttons and other components need to be manually disassembled during the recycling process to separate the PET material from the clothes, which increases the difficulty of recycling.

[0003] Because PET fibers are closely combined with zippers or buttons, delicate and time-consuming manual operations are required to ensure the effective separation of different plastics. Such a disassembly process not only increases labor costs, but also reduces recycling efficiency and benefits. In addition, if these components are not properly disassembled and sorted, it may lead to the mixing of different plastics, further affecting the reuse of resources after recycling. Summary of the invention

[0004] At least one embodiment of the present invention provides a method for manufacturing a modified polyester composition, comprising the following steps. A polyester material is provided, wherein the polyester material includes a polymer of polyethylene terephthalate and an oligomer of polyethylene terephthalate, and the characteristic viscosity of the polyester material is between 0.5 dL / g and 0.6 dL / g. A heating and decompression process is performed on the polyester material to reduce the oligomers of polyethylene terephthalate in the polyester material and increase the characteristic viscosity of the polyester material to between 0.6 dL / g and 0.92 dL / g. A nucleating agent, an antioxidant and a filler material are mixed into the polyester material, and the crystallinity of the polyester material is increased to obtain a modified polyester composition comprising a modified polyester and the filler material, wherein the content of the nucleating agent in the modified polyester composition is 0.5 wt% to 3 wt%, and the crystallinity of the modified polyester at 23°C is 15% to 28%.

[0005] At least one embodiment of the present invention provides a modified polyester composition, which includes a modified polyester and a filling material. The modified polyester includes a polyester material, a crystal nucleating agent and an antioxidant. The polyester material includes a polymer of polyethylene terephthalate. The characteristic viscosity of the polyester material before mixing with the crystal nucleating agent is between 0.6dL / g and 0.92dL / g. The content of the crystal nucleating agent in the modified polyester composition is 0.5wt% to 3wt%, and the crystallinity of the modified polyester at 23°C is 15% to 28%. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] none DETAILED DESCRIPTION

[0007] Hereinafter, embodiments of the present invention will be described in detail. However, these embodiments are illustrative only, and the present invention is not limited thereto.

[0008] In this article, the range expressed by "a value to another value" is a summary expression method to avoid listing all the values ​​in the range one by one in the specification. Therefore, the description of a specific numerical range covers any value in the numerical range and a smaller numerical range defined by any value in the numerical range, just as the arbitrary value and the smaller numerical range are written in the description text of the specification.

[0009] The present invention provides a method for manufacturing a modified polyester composition. First, a polyester material is provided. In some embodiments, the PET in the polyester material may include virgin polyester resin, recycled polyester or a combination thereof. Virgin polyester is a generally existing newly produced polyester. Recycled polyester may include physically recycled polyester and / or chemically recycled polyester.

[0010] For example, the method for obtaining recycled polyester includes: collecting various types of waste polyester resin materials, classifying the waste polyester resin materials according to their types, colors, and uses, and compressing and packaging the waste polyester resin materials and then transporting them to a waste treatment plant.

[0011] In some embodiments, the waste polyester resin material is recycled PET bottles, film materials, fibers, etc., but the present invention is not limited thereto. Other components on the waste polyester resin material (such as the bottle cap, label and adhesive of the PET bottle) are removed. Then, the waste polyester resin material is cut and crushed, and the bottle mouth, liner and bottle body of different materials in the PET bottle are separated by flotation and other methods. In addition, the crushed waste polyester resin material is dried to obtain the processed recycled polyester material (i.e., recycled polyethylene terephthalate (r-PET)), so as to facilitate the subsequent manufacturing process.

[0012] The recycled polyester material is further processed to obtain recycled polyester pellets. The recycled polyester pellets can be physically recycled polyester pellets or chemically recycled polyester pellets.

[0013] In some embodiments, physically recycled polyester resins refer to polyester resins obtained by physical recycling, including physically recycled conventional polyester resins and physically recycled modified polyester resins. Physically recycled conventional polyester resins do not have any functional additives added during the recycling process, while physically recycled modified polyester resins are prepared by adding functional additives (e.g., lubricants, colorants, weathering modifiers, crystal nucleating agents, and matte agents) during the recycling process to produce physically recycled modified polyester resins with different functions.

[0014] In some embodiments, the manufacturing method of chemically recycled polyester pellets includes: cutting recycled polyester materials (e.g., PET bottle flakes), and putting the cut bottle flakes into a chemical depolymerization liquid to break the polyester molecules in the recycled polyester material, thereby achieving the effect of depolymerizing the recycled polyester material, and further obtaining a polyester composition with a shorter molecular chain and an ester monomer composed of a diacid unit and two diol units, such as bis(hydroxyethyl) terephthalate (BHET). Then, separating and purifying the oligomer mixture, and then repolymerizing the oligomer mixture to obtain chemically recycled polyester pellets. In some embodiments, in the process of chemical reprocessing, functional additives (e.g., lubricants, colorants, weathering modifiers, crystal nucleating agents, and matte agents, etc.) can also be added to the oligomer mixture, and then repolymerized to obtain chemically recycled modified polyester pellets with different functions.

[0015] Before modification, the polyester material composed of the aforementioned virgin polyester and / or the aforementioned recycled polyester includes PET polymers and PET oligomers, and the intrinsic viscosity is between 0.5 dL / g and 0.6 dL / g. In addition, before modification, the PET in the polyester material has a melting point of 242 degrees Celsius to 252 degrees Celsius. In some embodiments, before modification, the crystallinity of the PET in the polyester material at room temperature (about 23°C) is 5% to 15%. In some embodiments, before modification, the cooling crystallization temperature (Tcc) of the polyester material is 160°C to 185°C, and the heating crystallization temperature (Thc) is 105°C to 135°C.

[0016] Next, the polyester material is modified to obtain modified polyester. Specifically, the polyester material modification includes performing a heating and decompression process on the polyester material, and mixing additives such as a crystal nucleating agent, an antioxidant, and a filling material into the polyester material. The specific description is as follows.

[0017] The polyester material is subjected to a heating and decompression process to reduce the oligomers of PET in the polyester material, thereby increasing the viscosity of the polyester material. The viscosity increasing method includes solid viscosity increasing and / or liquid viscosity increasing. For example, a polyester material containing a polymer of PET and an oligomer of PET is placed in a chamber, and the chamber is decompressed and heated to volatilize the oligomers of PET. In some embodiments, the polyester material is heated to 190° C. to 220° C. and decompressed to 0.01 kPa to 0.05 kPa, and solid-state polymerization is performed for 6 to 10 hours. Due to the reduction in the content of oligomers, the intrinsic viscosity of the polyester material can be increased to between 0.6 dL / g and 0.92 dL / g, preferably between 0.8 dL / g and 0.92 dL / g.

[0018] A nucleating agent, an antioxidant and a filler material are mixed into the polyester material. The nucleating agent can increase the crystallization rate, thereby making the subsequently obtained modified polyester have a high degree of crystallinity. In some embodiments, the nucleating agent includes an organic nucleating agent, an inorganic nucleating agent or a combination of the two. The organic nucleating agent is selected from at least one of the following materials: organic sodium salts such as sodium benzoate, sodium montanate and sodium salt copolymer of ethylene-methyl methacrylate (EMMA-sodium salt, also known as surlyn), and the inorganic nucleating agent is selected from at least one of the following materials: inorganic micro-nano powders such as talc, titanium dioxide, silicon dioxide and calcium carbonate. The inorganic nucleating agent used as the nucleating agent has a particle size of less than 2 microns. For example, the average particle size of the inorganic nucleating agent is 500 nanometers to 1500 nanometers. In some embodiments, the content of the nucleating agent in the modified polyester composition finally obtained is 0.5wt% to 3wt%, preferably 1wt% to 2wt%.

[0019] In some embodiments, the antioxidant is selected from at least one of the following materials: hindered phenol antioxidants, phenolic antioxidants, mixed antioxidants, and phosphite antioxidants. In some embodiments, the content of the antioxidant in the modified polyester composition is 0.1 wt % to 1 wt %, such as 0.2 wt % to 0.8 wt % or 0.4 wt % to 0.6 wt %.

[0020] In some embodiments, the filler material is selected from at least one of the following materials: glass fiber, carbon fiber, metal oxide, silicon dioxide, etc. In some embodiments, the content of the filler material in the modified polyester composition obtained is 0.5wt% to 50wt%, such as 10wt% to 40wt% or 20wt% to 30wt%. In some embodiments, the filler material is fibrous or granular, and when the filler material is granular, its average particle size is 5 microns to 50 microns.

[0021] In some embodiments, a crystal nucleating agent, an antioxidant, a filler material, and an unmodified polyester material are added to a twin-screw extruder for mixing, and a modified polyester composition can be obtained after extrusion. In some embodiments, the crystal nucleating agent, the antioxidant, and the filler material are mixed into the polyester material at 260° C. to 280° C. In some embodiments, other additives such as a flow lubricant, a dye, and a masterbatch can also be mixed into the polyester material.

[0022] In some embodiments, the modified polyester composition has a crystallinity of 15% to 28% at 23°C. In some embodiments, the cooling crystallization temperature (Tcc) of the modified polyester composition is 190°C to 210°C, and the heating crystallization temperature (Thc) is 100°C to 130°C. In some embodiments, the tensile strength of the modified polyester composition is 60MPa to 90MPa. In some embodiments, the melting point of the modified polyester composition is 245°C to 255°C.

[0023] In order to prove that the modified polyester composition proposed in the present invention has excellent heat resistance and excellent mechanical strength, Table 1 presents the mechanical properties and thermal properties of some experimental examples and comparative examples. In Comparative Example 3 and Experimental Example 2, the filler material is spherical (talcum powder) with a particle size of about 5 microns. In Experimental Example 3, the glass fiber is fibrous (or rod-shaped) with a fiber diameter of about 10 microns to 13 microns. In Experimental Example 1, an organic sodium benzoate nucleating agent is added, and in Experimental Examples 2 and 3, an inorganic talcum powder nucleating agent is mainly added.

[0024] Table 1

[0025]

[0026] From Comparative Example 2 and Experimental Example 1, it can be seen that the impact strength, tensile strength, flexural modulus and heat deformation temperature of polyester can be improved by adding a crystal nucleating agent. In addition, from Experimental Examples 1 to 3, it can be seen that the flexural modulus and heat deformation temperature of polyester can be improved by adding a filler material, and Experimental Example 3 with the addition of glass fiber is better.

Claims

1. A method for producing a modified polyester composition, comprising: Providing a polyester material, wherein the polyester material comprises a polymer of polyethylene terephthalate and an oligomer of polyethylene terephthalate, and the intrinsic viscosity of the polyester material is between 0.5 dL / g and 0.6 dL / g; Performing a heating and decompression process on the polyester material to reduce the oligomers of the polyethylene terephthalate in the polyester material and increase the intrinsic viscosity of the polyester material to between 0.6 dL / g and 0.92 dL / g; A crystal nucleating agent, an antioxidant and a filling material are mixed into the polyester material, and the crystallinity of the polyester material is improved to obtain the modified polyester composition comprising the modified polyester and the filling material, wherein the content of the crystal nucleating agent in the modified polyester composition is 0.5wt% to 3wt%, and the crystallinity of the modified polyester at 23°C is 15% to 28%.

2. The method for producing a modified polyester composition according to claim 1, wherein the content of the antioxidant in the modified polyester composition is 0.1wt% to 1wt%, and the content of the filler in the modified polyester composition is 0.5wt% to 50wt%.

3. The method for producing a modified polyester composition according to claim 1, wherein the crystal nucleating agent comprises an organic crystal nucleating agent, an inorganic crystal nucleating agent or a combination of the two.

4. The method for producing a modified polyester composition according to claim 3, wherein the organic nucleus agent is selected from at least one of the following materials: sodium benzoate, sodium montanate and sodium salt copolymer of ethylene-methyl methacrylate, and the inorganic nucleus agent is selected from at least one of the following materials: talc, titanium dioxide, silicon dioxide and calcium carbonate, and the filler material is selected from at least one of the following materials: glass fiber, carbon fiber, metal oxide and silicon dioxide. 5 . The method for producing a modified polyester composition according to claim 1 , wherein the crystal nucleating agent, the antioxidant and the filler are mixed into the polyester material at 260° C. to 280° C.

6. A modified polyester composition comprising: The invention comprises a modified polyester and a filling material, wherein the modified polyester comprises a polyester material, a crystal nucleating agent and an antioxidant, wherein the polyester material comprises a polymer of polyethylene terephthalate, wherein the intrinsic viscosity of the polyester material before being mixed with the crystal nucleating agent is between 0.6 dL / g and 0.92 dL / g, and the content of the crystal nucleating agent in the modified polyester composition is between 0.5 wt % and 3 wt %. wt%, and the modified polyester has a crystallinity of 15% to 28% at 23°C.

7. The modified polyester composition according to claim 6, wherein the content of the antioxidant in the modified polyester composition is 0.1wt% to 1wt%, and the content of the filler in the modified polyester composition is 0.5wt% to 50wt%.

8. The modified polyester composition according to claim 6, wherein the nucleus agent comprises an organic nucleus agent, an inorganic nucleus agent or a combination of the two, wherein the organic nucleus agent is selected from at least one of the following materials: sodium benzoate, sodium montanate and ethylene-methyl methacrylate sodium salt copolymer, and the inorganic nucleus agent is selected from at least one of the following materials: talc, titanium dioxide, silicon dioxide and calcium carbonate.

9. The modified polyester composition according to claim 6, wherein the filler material is selected from at least one of the following materials: glass fiber, carbon fiber, metal oxide and silicon dioxide.

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