Polyamide composition as well as preparation method and application thereof

Abstract

The invention relates to a polyamide composition as well as a preparation method and application thereof. The polyamide composition is prepared from the following components in parts by weight: 77 to 97 parts of polyamide resin, 3 to 23 parts of a toughening agent, 0.08 to 0.6 part of an antioxidant A, 0.08 to 0.6 part of an antioxidant B and 0.08 to 0.6 part of a copper salt heat stabilizer. The antioxidant A is a sulfur-containing antioxidant, and the sulfur-containing antioxidant has a thiocarbonyl thio group (-C (= S)-S-); the antioxidant B comprises a phosphite ester antioxidant and / or a hindered phenol antioxidant. According to the toughened polyamide composition, the sulfur-containing antioxidant with thiocarbonyl sulfenyl is introduced and is matched with the phosphite antioxidant and / or the hindered phenol antioxidant and the copper salt heat stabilizer, so that the thermo-oxidative aging resistance of the toughened polyamide composition is jointly improved.

Description

Technical Field

[0001] This invention relates to the field of engineering plastics technology, and in particular to a polyamide composition, its preparation method, and its application. Background Technology

[0002] Polyamide (PA) is a widely used engineering plastic with excellent comprehensive properties, including mechanical properties, heat resistance, wear resistance, chemical resistance, and self-lubricating properties. There are many types of PA, such as PA6, PA66, PA46, PA610, and PA612. Toughened PA materials are widely used in the manufacture of cable ties in both consumer and industrial applications. However, for automotive cable ties, to ensure long-term safe use in the high-temperature environment surrounding the engine, major OEMs have proposed high-temperature thermo-oxidative aging requirements for cable tie materials.

[0003] CN106280435A discloses a high-temperature aging resistant PA material and its preparation method, which is prepared from the following raw materials by weight percentage: PA66 60-70%, PA6 5-10%, anti-aging agent 0.5-1%, lubricant 0.4-1%, and glass fiber 20-30%, wherein the sum of the weight percentages of the raw materials is 100%. The anti-aging agent is a mixture of bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite and copper salt.

[0004] CN102382467A discloses a high-temperature resistant PA66 material and its preparation method, which is composed of the following components: 100 parts of PA66 resin, 0.45-1.2 parts of lubricant, 0.5-2 parts of heat stabilizer, 0.15-0.6 parts of nucleating agent, 0.4-1.2 parts of antioxidant, and 60 parts of glass fiber. The heat stabilizer is one or a mixture of two of organic copper salts and inorganic copper salts.

[0005] The heat aging resistance of toughened PA materials is poor. In traditional solutions, the main method to improve the heat aging resistance of toughened PA materials is to add copper salt heat aging agents. However, this solution can no longer meet the requirements of the higher aging temperatures and longer aging times demanded by OEMs today.

[0006] Therefore, it is necessary to provide a toughened polyamide material with better heat aging resistance. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a polyamide composition, its preparation method, and its applications. This invention introduces a sulfur-containing antioxidant with a thiocarbonyl sulfide group, which, in conjunction with phosphite antioxidants and / or hindered phenolic antioxidants and copper salt heat stabilizers, collectively improves the heat and oxygen aging resistance of the toughened polyamide composition.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a polyamide composition comprising, by weight parts, the following components:

[0010] 77-97 parts of polyamide resin

[0011] toughening agent 3-23 parts

[0012] Antioxidant A 0.08-0.6 parts

[0013] Antioxidant B 0.08-0.6 parts

[0014] Copper salt heat stabilizer: 0.08-0.6 parts;

[0015] The antioxidant A is a sulfur-containing antioxidant, which has a thiocarbonyl thio group (-C(=S)-S-).

[0016] Antioxidant B includes phosphite antioxidants and / or hindered phenolic antioxidants.

[0017] In this invention, the amount of polyamide resin can be, for example, 77 parts, 80 parts, 85 parts, 90 parts, 95 parts, 97 parts, etc., preferably 84-95 parts; the amount of toughening agent can be, for example, 3 parts, 5 parts, 10 parts, 15 parts, 20 parts, 23 parts, etc., preferably 5-15 parts; the amount of antioxidant A can be, for example, 0.08 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0. The amount of antioxidant B can be, for example, 0.08 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, etc., preferably 0.1-0.6 parts; the amount of copper salt heat stabilizer can be, for example, 0.08 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, etc., preferably 0.2-0.5 parts.

[0018] Preferably, the polyamide resin in the polyamide composition is 78-97% by mass, and more preferably 84-95%.

[0019] Preferably, the mass percentage of antioxidant A in the polyamide composition is 0.08-0.6%, more preferably 0.1-0.5%.

[0020] In traditional solutions, the toughening properties of PA materials affect their heat aging resistance. This invention introduces a sulfur-containing antioxidant with thiocarbonyl sulfide groups, which has high reactivity and can capture and reduce the concentration of free radicals that rise sharply in the resin system under high temperature conditions, thereby reducing the destructive effect of free radicals on the polymer chain. In addition, this antioxidant can be regenerated by donating electrons to combine with other free radicals (single electrons) generated in the resin system, thus avoiding being depleted in a short time.

[0021] This invention introduces antioxidant A (a sulfur-containing antioxidant with thiocarbonyl sulfide groups), which works in conjunction with antioxidant B (phosphite antioxidant and / or hindered phenolic antioxidant). The two have a synergistic effect in heat and oxygen aging resistance. At the same time, copper salt heat stabilizers are added to assist in improving the heat and oxygen aging resistance and toughening properties of polyamide resin.

[0022] Preferably, the polyamide resin comprises aliphatic polyamide and / or aromatic polyamide.

[0023] Preferably, the aliphatic polyamide comprises PA66 and / or PA6.

[0024] Preferably, the viscosity of the polyamide resin is 2.2-2.8 (e.g., 2.2, 2.4, 2.6, 2.8, etc.).

[0025] In this invention, the viscosity of the polyamide resin is tested according to ISO 307.

[0026] Preferably, the toughening agent is a polyolefin elastomer grafted with polar groups.

[0027] Preferably, the polar group is maleic anhydride.

[0028] Preferably, the grafting rate of the maleic anhydride is not less than 0.5%, and more preferably 0.8-2% (for example, it can be 0.8%, 0.9%, 1%, 1.1%, 1.2%, 2%, etc.).

[0029] In this invention, the grafting rate is tested using acid-base titration.

[0030] Preferably, the polyolefin elastomer is an ethylene-α-olefin copolymer, more preferably an ethylene-octene copolymer and / or an ethylene-butene copolymer.

[0031] Preferably, the sulfur-containing antioxidant includes any one or a combination of at least two of 1,4-bis-(ethoxythiocarbonyl mercaptomethyl)benzene, 3-benzylthioalkylthiocarbonylthioalkylpropionic acid, 2-[(ethylthio)carbonylthio]thio]-2-methylpropionic acid, or methyl cyanomethyl methyl (phenyl)aminodithiocarbamate.

[0032] Preferably, the phosphite antioxidant includes any one or a combination of at least two of the following: tris(2,4-di-tert-butylphenyl) phosphite, pentaerythritol diphosphite bis(octadecyl) phosphite, cyclic pentapentaerythritol diphosphite bis(2,6-di-tert-butyl-4-methylphenyl phosphite), or bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite.

[0033] Preferably, the hindered phenolic antioxidant includes pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and / or N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine.

[0034] Preferably, the copper salt heat stabilizer includes cuprous bromide heat stabilizers and / or cuprous iodide heat stabilizers.

[0035] Preferably, the copper salt heat stabilizer includes a compound of cuprous bromide and alkali metal halide in a mass ratio of 1:(3-20), preferably 1:(5-10); a compound of cuprous iodide and alkali metal halide in a mass ratio of 1:(3-20), preferably 1:(5-10); a compound of cuprous bromide, alkali metal halide and magnesium stearate in a mass ratio of 1:(3-20):(0.01-10), preferably 1:(5-10):(0.1-5); and a compound of cuprous iodide, alkali metal halide and magnesium stearate in a mass ratio of 1:(3-20):(0.01-10), preferably 1:(5-10):(0.1-5).

[0036] Preferably, the alkali metal halide includes any one or a combination of at least two of the iodides and / or bromides of Li, Na, or K.

[0037] In a second aspect, the present invention provides a method for preparing a polyamide composition according to the first aspect, the method comprising: mixing the components, extruding and granulating to obtain the polyamide composition.

[0038] Preferably, the extrusion granulation temperature is 250-290℃ (e.g., 250℃, 260℃, 270℃, 280℃, 290℃, etc.).

[0039] Thirdly, the present invention provides the use of the polyamide composition according to the first aspect in the preparation of automotive parts.

[0040] Fourthly, the present invention provides a cable tie for automobiles, the cable tie comprising the polyamide composition according to the first aspect.

[0041] Compared with the prior art, the present invention has at least the following beneficial effects:

[0042] This invention introduces antioxidant A (a sulfur-containing antioxidant with thiocarbonyl sulfide groups), which works in conjunction with antioxidant B (phosphite antioxidant and / or hindered phenolic antioxidant). The two have a synergistic effect in heat and oxygen aging resistance. At the same time, copper salt heat stabilizers are added to assist in improving the heat and oxygen aging resistance and toughening properties of polyamide resin. Detailed Implementation

[0043] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0044] The sources of materials used in the following embodiments and comparative examples are as follows:

[0045] A. Resin

[0046] A1 PA66, grade PA66 EPR24, purchased from Henan Shenma;

[0047] A2 PA6, grade PA6 BE3250, purchased from Jiangsu Hongsheng;

[0048] B. Toughening agent

[0049] B1 Maleic anhydride-grafted polyolefin elastomer, grade N406, purchased from Ningbo Nengzhiguang.

[0050] B2 Maleic anhydride-grafted polyolefin elastomer, brand name KT-915, purchased from Shenyang Ketong;

[0051] C. Sulfur-containing antioxidants

[0052] C1 1,4-bis-(ethoxythiocarbonyl mercaptomethyl)-benzene, purchased from TCI;

[0053] C2 3-Benzylthioalkylthiocarbonylthioalkylpropionic acid, purchased from TCI;

[0054] C3 methyl(phenyl)aminodithiocarbamate cyanomethyl ester, purchased from TCI;

[0055] C4 2-[(ethylthio)carbonylthio]thio]-2-methylpropionic acid, purchased from TCI;

[0056] D. Phosphite antioxidants

[0057] D1 Tris(2,4-di-tert-butylphenyl) phosphite, brand name SONOX 168, purchased from Shandong Sanfeng;

[0058] D2 Cyclic pentapentanetetramethyldi(2,6-di-tert-butyl-4-methylphenylphosphite), brand name PEP 36, purchased from Adeka, Japan;

[0059] E. Hindered phenolic antioxidants

[0060] E1 pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], brand name SONOX 1010, purchased from Shandong Sanfeng;

[0061] E2 N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, SONOX 1098, purchased from Tianjin Lialong;

[0062] F. Copper salt heat stabilizers

[0063] F1 BRUGGOLEN H328F, Brugmann, cuprous iodide and potassium bromide in a mass ratio of 1:7;

[0064] F2 8:1:1 KI / CUI / ZN STEARATE BLEND, with a mass ratio of 8:1:1 potassium iodide, cuprous iodide and zinc stearate, leading chemistry, cuprous iodide class;

[0065] G. Thioester antioxidants

[0066] G1 pentaerythritol tetrakis(3-lauryl thiopropionate), brand name RIANOX 412S, purchased from Rianon.

[0067] Examples 1-10, Comparative Examples 1-3

[0068] The above examples and comparative examples each provide a polyamide composition, the types and weight parts of which are shown in Table 1 and Table 2 (" / " indicates that the component is not contained).

[0069] The preparation methods of the polyamide compositions provided in the above embodiments and comparative examples include:

[0070] The components are added to a mixer according to the specified ratio and mixed for 5 minutes. Then, the mixture is added to the main feed hopper of an extruder and extruded and granulated through a twin-screw extruder to obtain a polyamide composition. The twin-screw extruder has a rotation speed of 300 r / min and a temperature of 260℃.

[0071] The polyamide compositions provided in Examples 1-10 and Comparative Examples 1-3 were subjected to the following performance tests, and the results are summarized in Tables 1 and 2.

[0072] (1) Thermo-oxidative aging test: The material is injection molded into a thin sheet of about 1 mm and placed in a thermo-oxidative aging oven at 150°C. Every 100 h, it is taken out to determine whether it breaks. The thermo-oxidative aging resistance is judged based on the bending and breaking performance of the material after aging.

[0073] (2) Tensile strength: ISO 527.

[0074] (3) Notched impact strength: ISO 179.

[0075] Table 1

[0076]

[0077] Table 2

[0078]

[0079] The test results show that:

[0080] (1) As can be seen from Examples 1 to 10, the present invention introduces sulfur-containing antioxidants with thiocarbonyl sulfide groups, which, in combination with phosphite antioxidants and / or hindered phenolic antioxidants and copper salt heat stabilizers, provide the toughened polyamide composition with good resistance to heat and oxygen aging. Specifically, the fracture time point after heat and oxygen aging at 150°C is ≥900 h, the tensile strength is 47.1-72.2 MPa, and the notched impact strength is 10.4-91.8 kJ / m. 2 In Example 7, the toughening agent content was increased from 10 parts to 20 parts, which is higher than the brittle-tough transition point of this type of material (usually between 10-15 parts). As a result, the material underwent a transition from brittle fracture to toughness, and thus the toughness increased significantly. It is generally believed that this phenomenon is due to the fact that when the toughening agent content is increased to a critical value, the toughening agent phase is better linked into a whole, thereby better dispersing the stress.

[0081] (2) As can be seen from the comparison between Example 1 and Comparative Examples 1-3, by reasonably combining sulfur-containing antioxidants with thiocarbonyl groups and phosphite antioxidants (or hindered phenolic antioxidants), they have a synergistic effect in heat and oxygen aging resistance, and jointly improve the heat and oxygen aging resistance of the material.

[0082] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A polyamide composition characterized in that, The polyamide composition comprises the following components by weight parts: Polyamide resin 77-97 parts Toughening agent 3-23 parts Antioxidant A 0.08-0.6 parts Antioxidant B 0.08-0.6 parts Copper salt heat stabilizer 0.08-0.6 parts The antioxidant A is a sulfur-containing antioxidant, and the sulfur-containing antioxidant has a thiocarbonylthio group (-C(=S)-S-); The antioxidant B comprises a phosphite antioxidant and / or a hindered phenol antioxidant.

2. The polyamide composition according to claim 1, characterized in that, The polyamide resin comprises an aliphatic polyamide and / or an aromatic polyamide; Preferably, the aliphatic polyamide comprises PA66 and / or PA6.

3. The polyamide composition according to claim 1, characterized in that, The toughening agent is a polyolefin elastomer grafted with a polar group; Preferably, the polar group is maleic anhydride; Preferably, the polyolefin elastomer is an ethylene alpha-olefin copolymer, preferably an ethylene-octene copolymer and / or an ethylene-butene copolymer.

4. The polyamide composition according to claim 1, characterized in that, The sulfur-containing antioxidant comprises any one or a combination of at least two of 1,4-bis-(ethoxylthiocarbonylmercaptomethyl)-benzene, 3-benzylsulfanylthiocarbonylsulfanylpropionic acid, 2-[(ethylthio)carbonylthio]-2-methylpropionic acid, or methyl(phenyl)aminodithioformic acid cyanomethyl ester.

5. The polyamide composition according to claim 1, characterized in that, The phosphite antioxidant comprises any one or a combination of at least two of tris(2,4-di-tert-butylphenyl) phosphite, pentaerythritol diphosphite dioctadecyl ester, cyclic pentaerythritetetrayl di(2,6-di-tert-butyl-4-methylphenyl phosphite), or bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite; Preferably, the hindered phenol antioxidant comprises tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] pentaerythritol ester and / or N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl) hexanediamine.

6. The polyamide composition according to claim 1, characterized in that, The copper salt heat stabilizer comprises a cuprous bromide salt heat stabilizer and / or a cuprous iodide salt heat stabilizer.

7. A process for the preparation of a polyamide composition according to any one of claims 1 to 6, characterized in that, The preparation method comprises mixing the components, and extruding and granulating to obtain the polyamide composition.

8. The preparation method according to claim 7, characterized in that, The temperature of the extruding and granulating is 250-290°C.

9. Use of the polyamide composition according to any one of claims 1-6 in the preparation of a vehicle component.

10. A tie for a vehicle, characterized by The automobile tie comprises the polyamide composition according to any one of claims 1-6.

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