Modified polyester composition and manufacturing method thereof

Abstract

To provide a modified polyester composition including modified polyester and a filler, with improved characteristics such as impact strength, tensile strength, flexural modulus, and heat deflection temperature.SOLUTION: The modified polyester includes a polyester material, a nucleating agent, and an antioxidant. The polyester material includes a polymer of polyethylene terephthalate. The content of the nucleating agent in the modified polyester is 0.5 wt.% to 3 wt.%.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a modified polyester composition and a method for producing the same. [Background technology]

[0002] As environmental awareness increases, the recycling of plastic products is receiving more attention. Currently, many clothing products use polyethylene terephthalate (PET) as a fiber material in the manufacturing process, and polyoxymethylene (POM) or nylon is used for zippers and buttons. However, since PET is a different plastic material from POM and nylon, elements such as zippers and buttons must be manually disassembled during the recycling process to separate the PET material from the clothing, making recycling more difficult.

[0003] Because PET fibers are tightly bound in zippers and buttons, effectively separating different plastic materials requires delicate and time-consuming manual labor. Such disassembly processes not only increase labor costs, but also reduce the efficiency and benefits of recycling. Moreover, if these elements are not properly disassembled and separated, different plastic materials may be mixed together, which may further affect the reuse of resources after recycling. Summary of the Invention [Problem to be solved by the invention]

[0004] The impact strength, tensile strength, flexural modulus, and heat distortion temperature of a polyester composition affect its applications, and it is important to improve these properties of the polyester composition. [Means for solving the problem]

[0005] At least one embodiment of the present invention provides a method for producing a modified polyester composition, the method comprising the steps of: providing a polyester material; the polyester material includes a polyethylene terephthalate polymer and a polyethylene terephthalate oligomer, and the intrinsic viscosity (IV) of the polyester material is 0.5 dL / g to 0.6 dL / g; the polyester material is subjected to a heating and decompression process to reduce the polyethylene terephthalate oligomer in the polyester material, and the intrinsic viscosity of the polyester material is increased to 0.6 dL / g to 0.92 dL / g; a nucleating agent, an antioxidant, and a filler are mixed into the polyester material to increase the crystallinity of the polyester material, thereby obtaining a modified polyester composition including a modified polyester and a filler; the content of the nucleating agent in the modified polyester composition is 0.5% by weight to 3% by weight, and the crystallinity of the modified polyester at 23°C is 15% to 28%.

[0006] At least one embodiment of the present invention provides a modified polyester composition including a modified polyester and a filler. The modified polyester includes a polyester material, a nucleating agent, and an antioxidant. The polyester material includes a polyethylene terephthalate polymer compound. The polyester material has an intrinsic viscosity of 0.6 dL / g to 0.92 dL / g before being mixed with the nucleating agent. The content of the nucleating agent in the modified polyester composition is 0.5% by weight to 3% by weight, and the crystallinity of the modified polyester at 23°C is 15% to 28%. Effect of the Invention

[0007] The impact strength, tensile strength, flexural modulus, and heat distortion temperature of polyester can be improved by the addition of nucleating agents. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present invention will be described in detail. However, these embodiments are merely examples and the present invention is not limited to these.

[0009] In this specification, the ranges indicated as "a certain value to another value" are general expressions to avoid listing all the values ​​within the range. Thus, the description of a particular range of values ​​includes any value within that range and any smaller range defined by any value within that range, just as if that any value and any smaller range were listed in the specification.

[0010] The present invention provides a method for producing a modified polyester composition. First, a polyester material is prepared. In some embodiments, the polyethylene terephthalate (PET) in the polyester material may include virgin polyester resin, recycled polyester, or a combination thereof. The virgin polyester resin is usually an existing new polyester. The recycled polyester may include physically recycled polyester and / or chemically recycled polyester.

[0011] For example, a method for obtaining recycled polyester includes collecting various types of polyester resin waste, separating them according to type, color, and application, compressing and packaging the polyester resin waste, and transporting it to a waste disposal site.

[0012] In some embodiments, the polyester resin waste material includes, but is not limited to, recycled PET bottles, film materials, fibers, etc. Other components of the waste polyester resin material (bottle caps, labels, adhesives, etc.) are removed. Next, the polyester resin waste material is cut and crushed, and the bottle neck, liner, and bottle body of different materials inside the PET bottle are separated using a method such as flotation. Furthermore, the crushed polyester resin waste material is dried to obtain recycled polyester processed material (recycled polyethylene terephthalate (r-PET)), which can facilitate the subsequent manufacturing process.

[0013] The recycled polyester material is further treated to obtain a recycled polyester resin, which may be a physically recycled polyester resin or a chemically recycled polyester resin.

[0014] In some embodiments, physically recycled polyester resin refers to polyester resin obtained by physical recycling, including physically recycled conventional polyester resin and physically recycled modified polyester resin. The physically recycled conventional polyester resin does not have functional additives added during the recycling process, while the physically recycled modified polyester resin has functional additives (lubricant, colorant, weather resistance modifier, nucleating agent, clouding agent, etc.) added to produce physically recycled modified polyester resin with different functions.

[0015] In some embodiments, the method for producing chemically recycled polyester resin includes cutting recycled polyester material (e.g., flakes of PET bottles) and introducing the cut flakes into a chemical depolymerization solution to cut the chains of polyester molecules in the recycled polyester material, so as to achieve the effect of depolymerizing the recycled polyester material, and further obtaining a polyester composition having shorter molecular chains and ester monomers such as bishydroxyethyl terephthalate (BHET) composed of a diacid unit and two diol units. Then, the oligomer mixture is separated and purified, and then the oligomer mixture is repolymerized to obtain a chemically recycled polyester resin. In some embodiments, in the process of chemical replication, functional additives (such as lubricants, colorants, weathering modifiers, nucleating agents, and clouding agents) may also be added to the oligomer mixture, and then repolymerization can be performed to obtain a chemically recycled modified polyester resin with different functions.

[0016] The polyester material made of virgin polyester resin before modification and / or recycled polyester contains a PET polymer compound and a PET oligomer, and has an intrinsic viscosity of 0.5 dL / g to 0.6 dL / g. Furthermore, the melting point of the PET in the polyester material before modification is 242°C to 252°C. In some embodiments, the PET in the polyester material before modification has a crystallinity of 5% to 15% at room temperature (about 23°C). In some embodiments, the polyester material before modification has a cooling crystallization temperature (Tcc) of 160°C to 185°C and a heating crystallization temperature (Thc) of 105°C to 135°C.

[0017] Then, the polyester material is modified to obtain a modified polyester. Specifically, the modification of the polyester material includes carrying out a heating and decompression process on the polyester material, and mixing additives such as nucleating agents, antioxidants, and fillers into the polyester material. The details are as follows:

[0018] The polyester material is subjected to a heating and decompression process to reduce the PET oligomers in the polyester material. This results in tackification of the polyester material. The tackification method includes solid tackification and / or liquid tackification. For example, a polyester material containing a PET polymer compound and a PET oligomer is placed in a chamber, and the chamber is decompressed and heated to volatilize the PET oligomers. In some embodiments, the polyester material is heated to 190°C to 220°C, decompressed to 0.01 kPa to 0.05 kPa, and subjected to solid-state polymerization for 6 hours to 10 hours. Due to the reduction in oligomer content, the intrinsic viscosity of the polyester material can be increased to 0.6 dL / g to 0.92 dL / g, preferably 0.8 dL / g to 0.92 dL / g.

[0019] Nucleating agents, antioxidants, and fillers are mixed into the polyester material. Nucleating agents can increase the crystallization rate, and therefore the crystallinity of the resulting modified polyester can be increased. In some embodiments, the nucleating agent comprises an organic nucleating agent, an inorganic nucleating agent, or a combination of both. The organic nucleating agent is selected from at least one of sodium benzoate, sodium montanate, ethylene-methyl methacrylate sodium salt copolymer (EMMA-sodium salt, also known as SURLYN), and other organic sodium salts. The inorganic nucleating agent is selected from at least one of talc powder, titanium dioxide, silicon dioxide, calcium carbonate, and other inorganic micro-nano powders. The particle size of the inorganic nucleating agent used as the nucleating agent is less than 2 μm. The average particle size of the inorganic nucleating agent is, for example, 500 nm to 1500 nm. In some embodiments, the content of the nucleating agent in the final modified polyester composition is 0.5% to 3% by weight, preferably 1% to 2% by weight.

[0020] In some embodiments, the antioxidant is selected from at least one of a hindered phenol-based antioxidant, a phenol-based antioxidant, a mixed antioxidant, and a phosphite-based antioxidant. In some embodiments, the content of the antioxidant in the final modified polyester composition is 0.1% to 1% by weight, for example, 0.2% to 0.8% by weight, or 0.4% to 0.6% by weight.

[0021] In some embodiments, the filler is selected from at least one of materials such as glass fiber, carbon fiber, metal oxide, silicon dioxide, etc. In some embodiments, the content of the filler in the final modified polyester composition is 0.5% to 50% by weight, for example, 10% to 40% by weight, or 20% to 30% by weight. In some embodiments, the filler is fibrous or granular. When the filler is granular, the average particle size is 5 μm to 50 μm.

[0022] In some embodiments, the nucleating agent, antioxidant, filler, and unmodified polyester material are added to a twin screw extruder and mixed to obtain a modified polyester composition after extrusion. In some embodiments, the nucleating agent, antioxidant, and filler are mixed into the polyester material at 260°C to 280°C. In some embodiments, other additives such as flow lubricants, dyes, and color masterbatches can also be mixed into the polyester material.

[0023] In some embodiments, the modified polyester composition has a degree of crystallinity of 15% to 28% at 23°C. In some embodiments, the modified polyester composition has a cooling crystallization temperature (Tcc) of 190°C to 210°C and a heating crystallization temperature (Thc) of 100°C to 130°C. In some embodiments, the modified polyester composition has a tensile strength of 60 MPa to 90 MPa. In some embodiments, the modified polyester composition has a melting point of 245°C to 255°C.

[0024] In order to prove that the modified polyester composition proposed by the present invention has excellent heat resistance and excellent mechanical strength, Table 1 shows the mechanical and thermal properties of several examples and comparative examples. In Comparative Example 3 and Example 2, the filler is spherical (talcum powder) with a particle size of about 5 μm. In Example 3, the glass fiber is fibrous (or rod-shaped) with a fiber diameter of about 10 μm to 13 μm. In Example 1, an organic sodium benzoate nucleating agent was added. In Examples 2 and 3, an inorganic talcum powder nucleating agent was mainly added. Impact strength tests were carried out according to the ASTM D256 standard. The obtained value indicates the total energy that the test sample can withstand when it breaks. The higher the value, the greater the impact strength (or resistance strength of the test sample) that the test sample can withstand. Tensile strength tests were carried out according to the ASTM D638 standard. The obtained value indicates the total energy that the test sample can withstand tensile deformation. The higher the value, the greater the tensile strength that the test sample can withstand. Flexural modulus was measured according to the ASTM D790 standard test method. The obtained value represents the resistance of the test specimen to bending strain and deformation. Higher values ​​indicate higher bending strength of the test specimen. Heat distortion temperature (HDT) was performed according to the ASTM D648 standard. It is a parameter that describes the relationship between heat and strain of the test sample and is an index of the heat resistance of polymers. During the HDT test, the polymer is subjected to a constant load and the temperature is increased at a constant rate until it reaches a temperature corresponding to the specified strain.

[0025] [Table 1]

[0026] It is seen from Comparative Example 2 and Example 1 that the addition of a nucleating agent improves the impact strength, tensile strength, flexural modulus, and heat distortion temperature of polyester. It is also seen from Examples 1 to 3 that the addition of a filler improves the flexural modulus and heat distortion temperature of polyester. Here, Example 3, in which glass fiber is added, is preferred. [Industrial Applicability]

[0027] The modified polyester composition of the present invention can be applied to hard plastic products such as zippers and buttons.

Claims

1. providing a polyester material, the polyester material comprising a polyethylene terephthalate polymer and a polyethylene terephthalate oligomer, the intrinsic viscosity of the polyester material being 0.5 dL / g to 0.6 dL / g; performing a heating and decompression process on the polyester material to reduce the oligomers of polyethylene terephthalate in the polyester material and increase the intrinsic viscosity of the polyester material to 0.6 dL / g to 0.92 dL / g; and mixing a nucleating agent, an antioxidant, and a filler with the polyester material to increase the crystallinity of the polyester material to obtain a modified polyester composition containing a modified polyester and the filler, wherein the content of the nucleating agent in the modified polyester composition is 0.5% by weight to 3% by weight, and the crystallinity of the modified polyester at 23° C. is 15% to 28%.

2. The modified polyester composition according to claim 1, wherein the content of the antioxidant in the modified polyester composition is 0.1% by weight to 1% by weight, and the content of the filler in the modified polyester composition is 0.5% by weight to 50% by weight.

3. The modified polyester composition of claim 1 , wherein the nucleating agent comprises an organic nucleating agent, an inorganic nucleating agent, or a combination of both.

4. 4. The modified polyester composition of claim 3, wherein the organic nucleating agent is selected from at least one of sodium benzoate, sodium montanate, and a sodium salt copolymer of ethylene-methyl methacrylate, the inorganic nucleating agent is selected from at least one of talcum powder, titanium dioxide, silicon dioxide, and calcium carbonate, and the filler is selected from at least one of glass fiber, carbon fiber, metal oxides, and silicon dioxide.

5. 2. The modified polyester composition of claim 1, wherein the 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 a modified polyester and a filler, the modified polyester comprising a polyester material, a nucleating agent, and an antioxidant, the polyester material comprising a polyethylene terephthalate polymer compound, the intrinsic viscosity of the polyester material before being mixed with the nucleating agent being 0.6 dL / g to 0.92 dL / g, the content of the nucleating agent in the modified polyester composition being 0.5% by weight to 3% by weight, and the crystallinity of the modified polyester at 23°C being 15% to 28%.

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

8. The nucleating agent comprises an organic nucleating agent, an inorganic nucleating agent, or a combination of both; 7. The modified polyester composition of claim 6, wherein the organic nucleating agent is selected from at least one of sodium benzoate, sodium montanate, and a sodium salt copolymer of ethylene-methyl methacrylate, and the inorganic nucleating agent is selected from at least one of talcum powder, titanium dioxide, silicon dioxide, and calcium carbonate.

9. 7. The modified polyester composition of claim 6, wherein the filler is selected from at least one of glass fiber, carbon fiber, metal oxides, and silicon dioxide.

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