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: 28 to 72 parts of PA (Polyamide) resin, 18 to 52 parts of glass fiber, 0.3 to 3.5 parts of epoxy resin and 0.8 to 5.5 parts of maleic anhydride grafted thermoplastic elastomer. Through cooperation of the epoxy resin and the maleic anhydride grafted thermoplastic elastomer, the creep resistance of the polyamide composition at normal temperature and the creep resistance at high temperature are obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and more specifically, to a polyamide composition and a preparation method and application thereof. Background Art

[0002] Nylon materials are widely used in various industries, mostly in various structural parts, functional parts, etc. During use, nylon parts are often under stress. As time goes by, the parts will creep, leading to product failure.

[0003] In addition, in automotive engine peripheral parts including intake manifolds, cooling fans, etc., nylon parts are often exposed to high temperature environments, and the creep problem of nylon parts in this case is more serious.

[0004] How to improve the creep resistance of nylon materials, especially the creep resistance at high temperatures, is one of the problems that urgently needs to be solved in the industry.

[0005] The composition of the Chinese patent entitled "Anti-creep polyamide composition, preparation method and prepared product" has good anti-creep performance, but does not focus on the anti-creep performance of the material at high temperature. Summary of the invention

[0006] The primary purpose of the present invention is to overcome the problem of poor creep resistance of nylon materials in the prior art, especially poor creep resistance at high temperatures, and to provide a polyamide composition.

[0007] A further object of the present invention is to provide a method for preparing the above polyamide composition.

[0008] A further object of the present invention is to provide the use of the polyamide composition in the preparation of automotive fasteners, automotive engine intake manifolds, cooling fans or wind shields.

[0009] The above-mentioned object of the present invention is achieved by the following technical solutions:

[0010] A polyamide composition comprising the following components in parts by weight:

[0011]

[0012] In the present invention, the addition of glass fiber is beneficial to improving the anti-creep performance of the polyamide composition.

[0013] The inventors of the present invention have found through research that the epoxy resin and maleic anhydride grafted thermoplastic elastomer in the polyamide composition can significantly improve the creep resistance of the polyamide composition at room temperature and at high temperature. The reason is that the epoxy group of the epoxy resin can react with the terminal amino group or terminal hydroxyl group of the PA resin to form a certain cross-linking structure, restricting the movement of the PA resin molecular chain, thereby improving the creep resistance of the polyamide composition at room temperature and high temperature; and the maleic anhydride grafted thermoplastic elastomer can also react with the epoxy resin to connect the PA resin molecules. When the polyamide composition is subjected to external force, the thermoplastic elastomer grafted with maleic anhydride can absorb and dissipate the energy from the external force, further improving the creep resistance of the polyamide composition at room temperature and high temperature.

[0014] In the present invention, PA resin is used as the main resin, and its content accounts for more than 30wt% of the polyamide composition.

[0015] Preferably, the relative viscosity of the PA resin is 2.0-3.0.

[0016] In the present invention, the relative viscosity of the PA resin can be measured under 96% concentrated sulfuric acid conditions according to ISO 307-2019.

[0017] Preferably, the PA resin is at least one of PA6, PA66, PA56 or PA612.

[0018] Preferably, the glass fiber is chopped glass fiber.

[0019] Preferably, the average cross-sectional diameter of the glass fiber is 6 to 15 μm.

[0020] Preferably, the average length of the glass fibers is 2 to 6 mm.

[0021] In the present invention, the average diameter and average length of the cross section of the glass fiber can be measured by optical microscopy.

[0022] The epoxy equivalent of the epoxy resin is 150 to 600 g / eq.

[0023] Preferably, the epoxy equivalent of the epoxy resin is 180 to 280 g / eq.

[0024] By selecting the epoxy resin with the epoxy equivalent, the obtained polyamide composition has better creep resistance at room temperature and high temperature.

[0025] The epoxy equivalent of the epoxy resin of the present invention can be measured according to the method of GB / T 4612-2008.

[0026] Preferably, the epoxy resin includes but is not limited to at least one of bisphenol A epoxy resin, bisphenol F epoxy resin or polyphenol epoxy resin.

[0027] Preferably, the grafting rate of maleic anhydride in the maleic anhydride grafted thermoplastic elastomer is 0.5-5 wt %.

[0028] More preferably, the grafting rate of maleic anhydride in the maleic anhydride grafted thermoplastic elastomer is 2-3 wt %.

[0029] When the grafting rate of maleic anhydride is within this range, the obtained polyamide composition has better creep resistance at room temperature and high temperature.

[0030] The maleic anhydride grafting rate of the maleic anhydride grafted thermoplastic elastomer can be tested by chemical titration method (KOH-ethanol solution).

[0031] Preferably, the maleic anhydride grafted thermoplastic elastomer is at least one of maleic anhydride grafted POE, maleic anhydride grafted SBS, or maleic anhydride grafted SEBS.

[0032] Preferably, the polyamide composition further comprises 0.1 to 5 parts of other additives.

[0033] Preferably, the other auxiliary agent is at least one of a lubricant, an antioxidant or a colorant.

[0034] Optionally, the lubricant includes but is not limited to an ester lubricant, including but not limited to at least one of EBS, stearamide or erucamide.

[0035] Optionally, the antioxidant is at least one of antioxidant 1010 , antioxidant 1018 and antioxidant 168 .

[0036] Optionally, the colorant is a black colorant, including but not limited to carbon black.

[0037] The preparation method of the polyamide composition comprises the following steps: mixing the components, melt-extruding, and granulating to obtain the polyamide composition.

[0038] Preferably, the temperature of the melt extrusion is 180-260° C.; the screw length-to-diameter ratio of the melt extruder is 40-48:1, and the screw speed is 400-800 r / min.

[0039] The use of the above polyamide composition in the preparation of automobile fasteners, automobile engine intake manifolds, cooling fans or wind shields is also within the protection scope of the present invention.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The invention significantly improves the creep resistance of the polyamide composition at room temperature and at high temperature by combining epoxy resin and maleic anhydride grafted thermoplastic elastomer. Specifically, the creep deformation rate of the polyamide composition at room temperature is less than 1.1%, and the creep deformation rate at high temperature is less than 1.6%. DETAILED DESCRIPTION

[0042] In order to more clearly and completely describe the technical solution of the present invention, the present invention is further described in detail through specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Various changes can be made within the scope of the rights of the present invention.

[0043] Some of the reagents selected in the embodiments and comparative examples of the present invention are described as follows:

[0044] PA resin 1#: PA6 M2400, Xinhui Meida, PA6, relative viscosity 2.4;

[0045] PA resin 2#: M2800, Xinhui Meida, PA6, relative viscosity 2.8;

[0046] PA resin 3#: U3600, INVISTA, PA66, relative viscosity 2.4;

[0047] Glass fiber: China Jushi, ECS10-03-568H, chopped glass fiber; average length is 3mm, average cross-section diameter is 10μm;

[0048] Epoxy resin 1#: EPON TM Resin 8132, Westlake Epoxy, bisphenol A epoxy resin, epoxy equivalent weight is about 200g / eq;

[0049] Epoxy resin 2#: EPON TM Resin 834, Westlake Epoxy, bisphenol A epoxy resin, epoxy equivalent weight is about 250g / eq;

[0050] Epoxy resin 3#: EPON TM Resin 3002, Westlake Epoxy, bisphenol A epoxy resin, epoxy content is about 550g / eq;

[0051] Phenolic resin crosslinker: Bakelite PF 2400, Hexion;

[0052] Ethylene-octene copolymer (POE): ENGAGE 8137, Dow.

[0053] Maleic anhydride grafted ethylene-octene copolymers 1 to 3# (MAH-POE1 to 3#) were prepared in-house. The process was as follows: MAH, ethylene-octene copolymer (ENGAGE 8137, Dow) and initiator (dicumyl peroxide) were mixed evenly, added into a twin-screw extruder for extrusion, pelletized, dried and used. The extrusion temperature was 160 to 200° C. The maleic anhydride grafting rate of the obtained maleic anhydride grafted ethylene-octene copolymer was regulated by adjusting the amount of MAH and ethylene-octene copolymer. The maleic anhydride grafting rates of maleic anhydride grafted ethylene-octene copolymer 1#, maleic anhydride grafted ethylene-octene copolymer 2# and maleic anhydride grafted ethylene-octene copolymer 3# were 1.0%, 2.0% and 3.0%, respectively.

[0054] Maleic anhydride grafted ethylene-octene copolymer 4# (MAH-POE4#): KT-915, Shenyang Ketong, maleic anhydride grafting rate ~0.6%;

[0055] Maleic anhydride grafted SEBS1# (MAH-SEBS1#): FG1924 G, Kraton, maleic anhydride grafting rate is 1%;

[0056] Other additives 1#: lubricant, ethylene bis stearamide, commercially available;

[0057] Other additives 2#: antioxidant, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, commercially available;

[0058] Unless otherwise specified, the components selected in the parallel examples and comparative examples (eg, glass fiber, other additive 1#, other additive 2#) are all the same commercially available products.

[0059] The polyamide compositions of the embodiments of the present invention and the comparative examples are prepared by the following preparation method:

[0060] (1) Weigh each component according to the ratio, put each component into a high-speed mixer, and mix them evenly to obtain a mixture.

[0061] (2) feeding the mixture into a twin-screw extruder, setting the temperature of the extruder to 180-260° C. (if the PA resin is PA6 resin, the temperatures of the zones are: 180° C., 220° C., 230° C., 240° C., 230° C., 230° C., 220° C., 220° C., 210° C.; if the PA resin is PA66 resin, the temperatures of the zones are: 230° C., 250° C., 250° C., 260° C., 265° C., 260° C., 255° C., 250° C., 250° C., 250° C.), the rotation speed is 400 r / min, and the aspect ratio of the screw is 40:1; and a polyamide composition is obtained by extruding and granulating after mixing, melting, homogenizing, and then extruding.

[0062] The performance of the polyamide compositions provided in the embodiments and comparative examples of the present invention was measured according to the following test methods:

[0063] Creep deformation rate: The tensile creep deformation rate at room temperature and the tensile creep deformation rate at high temperature are tested in accordance with ISO899-1:2003 standard. The test conditions are: stress 60MPa, time 1000h, test temperature 23℃ (room temperature) and 120℃ (high temperature, set by environmental test chamber), and the test specimens are standard tensile specimens injection molded according to ISO 527-1-2012, TYPE 1A.

[0064] Examples 1 to 11

[0065] Examples 1 to 11 provide a series of polyamide compositions, whose formulations are shown in Table 1.

[0066] Table 1 Formula of Examples 1 to 11 (parts by weight)

[0067]

[0068] Comparative Examples 1 to 4

[0069] Comparative Examples 1 to 4 provide a series of polyamide compositions, and their formulations are shown in Table 2.

[0070] Table 2 Formulas of Comparative Examples 1 to 4 (parts by weight)

[0071]

[0072] The properties of the polyamide compositions of the embodiments and comparative examples were measured according to the above-mentioned test methods. The test results are shown in Table 3.

[0073] Table 3 Performance test results of polyamide compositions of various embodiments and comparative examples

[0074]

[0075]

[0076] From Table 3, we can see that:

[0077] The creep deformation rates of the polyamide compositions of Examples 1 to 11 at room temperature are all below 1.1%, and the creep deformation rates at high temperatures are all below 1.6%, indicating that the polyamide compositions of the present invention have good creep resistance at room temperature and at high temperatures.

[0078] In Comparative Example 1, no epoxy resin is added and the amount of PA resin 1# is increased to replace the reduced amount of epoxy resin, resulting in a polyamide composition with poor creep resistance at room temperature and poor creep resistance at high temperature. In Comparative Example 2, a phenolic resin crosslinking agent is used to replace the epoxy resin, resulting in a polyamide composition with poor creep resistance at room temperature and poor creep resistance at high temperature. In Comparative Example 3, no maleic anhydride-grafted thermoplastic elastomer is added and the amount of PA resin 1# is increased to replace the reduced amount of MAH-POE1#, resulting in a polyamide composition with poor creep resistance at room temperature and poor creep resistance at high temperature. In Comparative Example 4, the thermoplastic elastomer added is not grafted with maleic anhydride, resulting in a polyamide composition with poor creep resistance at room temperature and poor creep resistance at high temperature.

[0079] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A polyamide composition, characterized in that The composition comprises the following components in parts by weight:

2. The polyamide composition according to claim 1, characterized in that: The relative viscosity of the PA resin is 2.0-3.

0.

3. The polyamide composition according to claim 1, characterized in that: The glass fibers are chopped glass fibers.

4. The polyamide composition according to claim 1, characterized in that: The epoxy equivalent of the epoxy resin is 150 to 600 g / eq.

5. The polyamide composition according to claim 1, characterized in that: The grafting rate of maleic anhydride in the maleic anhydride grafted thermoplastic elastomer is 0.5-5wt%.

6. The polyamide composition according to claim 1, characterized in that: The maleic anhydride grafted thermoplastic elastomer is at least one of maleic anhydride grafted POE, maleic anhydride grafted SBS, or maleic anhydride grafted SEBS.

7. The polyamide composition according to claim 1, characterized in that: The polyamide composition further comprises 0.1 to 5 parts of other additives.

8. The polyamide composition according to claim 7, characterized in that: The other auxiliary agent is at least one of a lubricant, an antioxidant or a colorant.

9. The method for preparing the polyamide composition according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing the components, melt-extruding and granulating to obtain the polyamide composition.

10. Use of the polyamide composition according to any one of claims 1 to 8 in the preparation of automotive fasteners, automotive engine intake manifolds, cooling fans or wind shields.

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