High-heat-stable polyester elastomer for blow molding, and preparation method and application thereof

Abstract

The application discloses a polyester elastomer with high thermal stability for blow molding and a preparation method and application thereof. The polyester elastomer comprises the following components in parts by weight: TPEE resin 92-98 parts, acid anhydride chain extender 1-5 parts. The polyester elastomer successfully solves the problem of low production efficiency of traditional TPEE tackifying and makes the prepared polyester elastomer have low melt index and high thermal stability.

Description

Technical Field

[0001] This invention relates to the field of thermoplastic elastomers, and particularly to a polyester elastomer with excellent thermal stability, its preparation method, and its applications. Background Technology

[0002] Thermoplastic polyester elastomers, due to their excellent high-temperature resistance and good solvent resistance, are commonly used in high-temperature, high-humidity, and oil-containing environments. Taking advantage of this characteristic, polyester elastomers are often modified to increase their viscosity, making them suitable for blow molding and application in automotive engine intake systems. However, traditional polyester elastomer viscosity-increasing techniques mostly employ solid-phase viscosity-increasing, which has long reaction times, low production efficiency, and is difficult to scale up. Isocyanate chain extension viscosity-increasing methods, on the other hand, suffer from poor thermal stability and are prone to degradation during blow molding. Therefore, there is an urgent need to develop a blow-molding-grade polyester elastomer with a simple preparation method, good thermal stability, and resistance to degradation for molding engine intake pipes. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention proposes a high thermal stability polyester elastomer for blow molding, its simple preparation method, and its applications.

[0004] This invention provides a polyester elastomer, comprising the following components by weight: 92-98 parts TPEE resin, such as 92, 93, 94, 95, 96, 97, or 98 parts; 1-5 parts anhydride chain extender, such as 1, 2, 3, 4, or 5 parts; and 1-3 parts inorganic metal salt, such as 1, 2, or 3 parts.

[0005] The TPEE resin preferably accounts for no less than 90% of the mass percentage of the polyester elastomer;

[0006] Using conventional injection-grade TPEE resin, by adding anhydride chain extenders and inorganic metal salts to the raw materials, the anhydride chain extenders react with TPEE during extrusion, increasing the molecular weight and releasing additional carboxyl groups. These carboxyl groups combine with the unreacted terminal carboxyl groups of TPEE and complex with metal ions in the inorganic metal salt to form ionomers, generating a network structure, which further increases the melt viscosity of the material and reduces the material's fluidity.

[0007] Furthermore, the melt flow index of the TPEE resin is 5-25 g / 10 min, preferably 5-15 g / 10 min, such as 5, 10, 12, or 15 g / 10 min. The test is conducted according to the ISO 1133-1-2011 standard method, with test conditions of 230°C and 2.16 kg.

[0008] Furthermore, the acid anhydride chain extender is selected from one or more of pyromellitic anhydride, 1,4,5,8-naphthalenetetracarboxylic anhydride, 3,4,9,10-tetracarboxylic anhydride or trimellitic anhydride, preferably pyromellitic anhydride.

[0009] Furthermore, the inorganic metal salt is selected from one or more of potassium chloride, sodium chloride, lithium chloride, lithium carbonate, potassium carbonate, and sodium bicarbonate, with potassium chloride being preferred.

[0010] Furthermore, the inorganic metal salt has a particle size of less than or equal to 500 mesh, preferably less than or equal to 800 mesh, and is tested in accordance with GB / T6003-2017.

[0011] Furthermore, the inorganic metal salt has a particle size of less than or equal to 2000 mesh. The smaller the particle size, the larger the contact area with the polymer, which is beneficial for a complete reaction.

[0012] Furthermore, the polyester elastomer further includes 0.2-0.5 parts by weight of antioxidant, such as 0.2, 0.3, 0.4, or 0.5 parts, and 0.3-0.6 parts by weight of light stabilizer, such as 0.3, 0.4, 0.5, or 0.6 parts.

[0013] Furthermore, the light stabilizer is a combination of hindered amine light stabilizers and triazine light stabilizers.

[0014] Further, the weight ratio of the hindered amine light stabilizer to the triazine light stabilizer is (2-1):1; wherein the hindered amine light stabilizer mainly functions to capture free radicals generated during polymer photo-oxidation and degradation, and can be selected from one or more of light stabilizers 622, 944, 783, 3853, 292, and 123; the triazine light stabilizer mainly functions to absorb ultraviolet light, and can be selected from one or more of UV-234, UV-236, and UV-237.

[0015] Furthermore, the antioxidant is selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 1790, antioxidant 168, antioxidant DLTP, and antioxidant 626.

[0016] This invention also provides a method for preparing the aforementioned polyester elastic material, characterized by comprising the following steps:

[0017] The components are weighed according to their weight proportions, mixed, extruded, and granulated to obtain the polyester elastomer. The present invention achieves TPEE thickening by mixing and then extruding the components. Compared with the traditional solid phase thickening method, it has lower equipment requirements and a short reaction time, which can be completed in only 85 seconds, resulting in high production efficiency.

[0018] The twin-screw extruder has a screw length-to-diameter ratio ≥ 56:1, preferably 60:1; the twin-screw extruder has a screw speed of 350-450 r / min and a melt mixing temperature of 120-180℃.

[0019] The present invention also provides the application of the described polyester elastomer in the preparation of gas transmission pipes, particularly in the preparation of engine intake pipes and air filter hoses.

[0020] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0021] (1) The present invention provides a polyester elastomer with high melt viscosity and low melt index;

[0022] (2) This invention provides a heat-stabilized polyester elastomer for blow molding with a high thermal decomposition temperature;

[0023] (3) The present invention provides a polyester elastomer with a simple and efficient preparation method, and the reaction time of the preparation process is only 85s. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0025] Example

[0026] The present invention will be further illustrated below with reference to specific embodiments and comparative embodiments. The following specific embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments, and are not in particular limited to the types of raw materials used in the following specific embodiments.

[0027] I. The sources of raw materials for the examples and comparative examples are as follows:

[0028]

[0029] The preparation method of the polyester elastomer in the embodiments and comparative examples of the present invention includes the following steps:

[0030] Weigh each component according to the weight percentage, mix each component in a high-speed mixer, and then add it to the main feed port of a twin-screw extruder. Extrusion and granulation are then performed to obtain the polyester elastomer. The twin-screw extruder has a screw length-to-diameter ratio ≥ 56:1, a screw speed of 350-450 r / min, and a melt mixing temperature of 120-180℃.

[0031] II. Performance Testing Methods

[0032] (1) Melt flow index test: Tested according to ISO 1133-1-2011 standard method, test conditions are 230℃, 10kg;

[0033] (2) Thermal stability test: The initial decomposition temperature of the material is detected by a thermogravimetric analyzer. The initial decomposition temperature is defined as the temperature at which the weight loss reaches 5%, i.e., the thermal decomposition temperature.

[0034] Table 1. Technical solutions and effects of the embodiments (unit: parts by weight)

[0035]

[0036]

[0037] Table 2 Comparative examples of technical solutions and effects (unit: parts by weight)

[0038]

[0039] Compared with Example 7, the chain extender added in Comparative Example 1 contained isocyanate groups, which significantly reduced the thermal decomposition temperature and resulted in poor thermal stability; Comparative Example 2 did not add any chain extender, resulting in a lower increase in the internal molecular weight of the polymer and a smaller decrease in the melt index, which was not as good as Example 7; Comparative Example 3 added an acid anhydride chain extender but did not add inorganic metal salts, which resulted in the polymer not forming ionic clusters, resulting in a higher melt index and a less effective thickening effect than Example 7.

[0040] Based on the test data of melt index and thermal decomposition temperature in Tables 1 and 2, the polyester elastomers prepared by Examples 1-12 have melt indexes below 7.3 g / 10 min and thermal decomposition temperatures of 421°C and above, even with increased material viscosity. They also have shorter reaction times and higher production efficiency, showing significant advantages over the comparative examples and effectively meeting the high standards required by customers and the market.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A polyester elastomer, characterized in that, By weight, it includes the following components: 92-98 parts of TPEE resin, 1-5 parts of anhydride chain extender 1-3 parts of inorganic metal salt; The inorganic metal salt is selected from one or more of potassium chloride, sodium chloride, lithium chloride, lithium carbonate, potassium carbonate, and sodium bicarbonate. The particle size of the inorganic metal salt is less than or equal to 800 mesh; The melt flow index of the TPEE resin is 5-25 g / 10min, and it is tested according to the ISO1133-1-2011 standard method. The test conditions are 230℃ and 2.16kg. The anhydride chain extender is selected from one or more of pyromellitic anhydride, 1,4,5,8-naphthalenetetracarboxylic anhydride, 3,4,9,10-tetracarboxylic anhydride, or trimellitic anhydride.

2. The polyester elastomer according to claim 1, characterized in that, The inorganic metal salt has a particle size of less than or equal to 2000 mesh.

3. The polyester elastomer according to claim 1, characterized in that, It also includes 0.2-0.5 parts antioxidant and 0.3-0.6 parts light stabilizer by weight.

4. The polyester elastomer according to claim 3, characterized in that, The light stabilizer is a combination of hindered amine light stabilizers and triazine light stabilizers.

5. The method for preparing the polyester elastic body according to any one of claims 1-4, characterized in that, Includes the following steps: Weigh each component according to its weight, mix, extrude, and granulate to obtain the polyester elastomer.

6. The use of the polyester elastomer according to any one of claims 1-4 in the preparation of gas transmission pipelines.

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