A polymer for improving polyamide performance and preparation method thereof

Abstract

This invention proposes a polymer for improving the properties of polyamide and its preparation method. The raw materials for preparing the polymer include ultra-high molecular weight polyethylene, high-density polyethylene, an initiator, a multifunctional monomer, and an antioxidant. The preparation method is as follows: the polyolefin, initiator, multifunctional monomer, and antioxidant are mixed and then extruded and granulated using a twin-screw extruder to obtain the polymer. When the polymer prepared by this invention is mixed with polyamide at a weight ratio of 1:(10-19), both the wear resistance and toughness of the polymer can be improved.

Description

Technical Field

[0001] This invention relates to the field of C08L23 / 06 technology, and more specifically to a polymer for improving the properties of polyamides and a method for preparing the same. Background Technology

[0002] Polyamide is one of the five most common engineering plastics. Equipment and components made from polyamide possess excellent properties such as wear resistance, corrosion resistance, and heat resistance. However, polyamide materials are difficult to process and have poor toughness, which limits the application of polyamide products. In actual production and processing, toughening agents, such as rubber and polyolefins, are often added to improve the toughness of polyamide.

[0003] Chinese patent CN104177825A discloses a polyamide toughening agent, whose raw materials include ethylene-octene copolymer elastomer, polypropylene, graft monomers, initiators, etc. Through toughening, it improves the impact resistance and toughness of polyamide; however, the toughening agent obtained by this patent has a limited effect on increasing the wear resistance of polyamide. Chinese patent CN106497055B discloses a wear-resistant nylon composite material, whose raw materials include polyamide resin, polyimide, ultrafine polytetrafluoroethylene powder, ethylene-vinyl acetate copolymer, etc. The resulting nylon composite material exhibits good wear resistance.

[0004] Based on this, the present invention proposes a polymer for improving the properties of polyamide and a method for preparing the same. Summary of the Invention

[0005] The first aspect of this invention provides a polymer for improving the properties of polyamide, wherein the raw materials for preparation, by weight, include 20-120 parts of polyolefin, 0.1-1 parts of initiator, 0.2-2 parts of multifunctional monomer, and 0.1-1 parts of antioxidant.

[0006] In a preferred embodiment, the polyolefin is obtained by copolymerization with a monomer selected from at least one of ethylene, propylene, butene, octene, pentene, butadiene, and hexene.

[0007] In a preferred embodiment, the monomer for the polyolefin is ethylene.

[0008] In a preferred embodiment, the polyolefin is a compound of polyolefin I and polyolefin II, wherein the melt index of polyolefin I at 190℃*10kg is 2-20g / 10min, and the melt index of polyolefin II at 190℃*2.16kg is 5-10g / 10min.

[0009] In a preferred embodiment, the weight ratio of polyolefin I to polyolefin II is (8-10):(0.01-2).

[0010] In a preferred embodiment, the weight ratio of polyolefin I to polyolefin II is (8-10):(0.1-1). More preferably, the weight ratio of polyolefin I to polyolefin II is 9:0.4.

[0011] In this application, polyolefin I is ultra-high molecular weight polyethylene with a density of 0.96-0.97 g / cm³. 3 Polyolefin II is high-density polyethylene. While high-density polyethylene optimizes the processing performance of ultra-high molecular weight polyethylene, it reduces the impact resistance and abrasion resistance of the final polymer. To maintain the various properties of the final polymer, nucleating agents are usually added. However, nucleating agents have poor compatibility in polyolefin systems. To further improve the compatibility of nucleating agents, additional raw materials need to be added.

[0012] However, the applicant discovered during the experiment that when ultra-high molecular weight polyethylene and high-density polyethylene were compounded in a weight ratio of 9:0.4, the resulting polymer exhibited good wear resistance and maintained its mechanical properties. The applicant believes this is because ultra-high molecular weight polyethylene and high-density polyethylene have good compatibility, and the high crystallinity of the high-density polyethylene added in this application can, to some extent, act as a nucleating agent for ultra-high molecular weight polyethylene. During the mixing and preparation of the polymer, the processing performance of the polymer was improved, while maintaining the polymer's wear resistance, toughness, and other mechanical properties.

[0013] In a preferred embodiment, the initiator is selected from at least one of peroxide initiators, azo initiators, and redox initiators.

[0014] In a preferred embodiment, the peroxide initiator is selected from at least one of dialkyl peroxides, acyl peroxides, hydroperoxides, and carbonate peroxides. Preferably, the peroxide initiator is a dialkyl peroxide.

[0015] In a preferred embodiment, the dialkyl peroxide is selected from at least one of 2,5-dimethyl-2,5-(tert-butylperoxy)ethane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-acetylene, di(tert-butylperoxyisopropyl)benzene, diisopropylbenzene peroxide, and ditert-butylperoxy.

[0016] In a preferred embodiment, the dialkyl peroxide is a compound of 2,5-dimethyl-2,5-(tert-butylperoxy)ethane and di(tert-butylperoxyisopropyl)benzene. In this application, the weight ratio of 2,5-dimethyl-2,5-(tert-butylperoxy)ethane to di(tert-butylperoxyisopropyl)benzene is 1:(0.1-2).

[0017] In a preferred embodiment, the weight ratio of 2,5-dimethyl-2,5-(tert-butylperoxy)ethane to di(tert-butylperoxyisopropyl)benzene is 1:0.2.

[0018] In a preferred embodiment, the functional group in the multifunctional monomer is selected from at least one of epoxy group, acid anhydride, carbon-carbon double bond, carboxyl group, hydroxyl group, and amino group.

[0019] In a preferred embodiment, the multifunctional monomer is selected from at least one of glycidyl methacrylate, maleic anhydride, acrylic acid, methacrylic acid, trimethylolpropane trimethacrylate, acrylamide, and polyethylene glycol propyl acrylate.

[0020] In a preferred embodiment, the multifunctional monomer is selected from at least one of glycidyl methacrylate, maleic anhydride, and acrylic acid. More preferably, the multifunctional monomer is glycidyl methacrylate.

[0021] In a preferred embodiment, the antioxidant is a compound of hindered phenolic antioxidants and phosphite antioxidants.

[0022] In a preferred embodiment, the weight ratio of the hindered phenolic antioxidant to the phosphite antioxidant is (2-3):(1-1.5). More preferably, the weight ratio of the hindered phenolic antioxidant to the phosphite antioxidant is 2.5:1.

[0023] In a preferred embodiment, the hindered phenolic antioxidant is selected from at least one of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl ester, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, and N,N'-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine. More preferably, the hindered phenolic antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0024] In a preferred embodiment, the phosphite antioxidant is selected from at least one of tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite, tetraphenyldipropylene glycol diphosphite, and triisooctyl phosphite. More preferably, the phosphite antioxidant is tris(2,4-di-tert-butylphenyl) phosphite.

[0025] In a preferred embodiment, the raw materials for preparation include, by weight, 90 parts of polyolefin I, 4 parts of polyolefin II, 0.8 parts of initiator, 2 parts of multifunctional monomer, and 0.8 parts of antioxidant.

[0026] The second aspect of this invention provides a method for preparing a polymer with improved polyamide properties, comprising the following steps: mixing a polyolefin, an initiator, a multifunctional monomer, and an antioxidant, and then extruding and granulating the mixture using a twin-screw extruder to obtain the polymer.

[0027] In a preferred embodiment, the extrusion temperature of the twin-screw extruder is 190-210°C, and the diameter-to-length ratio of the twin-screw extruder is (40-60):1.

[0028] The third aspect of this invention proposes the application of a polymer that improves the properties of polyamides, specifically polyamides, polybutylene terephthalate, polyethylene terephthalate, and polycarbonate, to enhance the wear resistance and toughness of the materials.

[0029] In a preferred embodiment, the weight ratio of the polymer to the polyamide material is 1:(10-19).

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The polymer prepared by this invention uses simple raw materials, with the addition of ultra-high molecular weight polyethylene and high-density polyethylene in a weight ratio of (8-10):(0.01-2). The high crystallinity and relatively low molecular weight of high-density polyethylene can act as a nucleating agent in the polymer, improving the processing performance of the polymer while maintaining its mechanical properties such as wear resistance and toughness.

[0032] 2. The polymer obtained by this invention, compared with conventional wear-resistant agents such as polytetrafluoroethylene, can improve both the wear resistance and toughness of polymers such as polyamide, polybutylene terephthalate, polyethylene terephthalate, and polycarbonate when used as an additive.

[0033] 3. The polymer obtained in this invention, when added as an additive to materials such as polyamide, polybutylene terephthalate, polyethylene terephthalate, and polycarbonate, can significantly improve toughness and wear resistance when used in an amount of 5-10%. Detailed Implementation

[0034] Example 1

[0035] The polymer for improving the properties of polyamide proposed in the first aspect of this embodiment is prepared by means of raw materials including 90 parts by weight of ultra-high molecular weight polyethylene, 4 parts of high-density polyethylene, 0.8 parts of initiator, 2 parts of glycidyl methacrylate, and 0.8 parts of antioxidant.

[0036] The melt flow index of ultra-high molecular weight polyethylene is 2-20 g / 10 min (190℃*10 kg), and the density is 0.96-0.97 g / cm³. 3 Purchased from Mitsui, Japan, model L3000.

[0037] The melt index of the high-density polyethylene is 5-10 g / 10 min (190℃*2.16 kg). It was purchased from Panjin Company in Liaoning Province, and the model number is 5070.

[0038] The initiator is 2,5-dimethyl-2,5-(tert-butylperoxy)ethane and di(tert-butylperoxyisopropyl)benzene in a weight ratio of 1:0.2. The CAS number of 2,5-dimethyl-2,5-(tert-butylperoxy)ethane is 78-63-7.

[0039] The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] in a weight ratio of 2.5:1, and the antioxidant is tris(2,4-di-tert-butylphenyl) phosphite.

[0040] The second aspect of this embodiment proposes a method for preparing a polymer that improves the properties of polyamide, comprising the following steps: mixing ultra-high molecular weight polyethylene, high-density polyethylene, initiator, glycidyl methacrylate, and antioxidant, and then extruding and granulating the mixture through a twin-screw extruder at 210°C, wherein the diameter-to-length ratio of the twin-screw extruder is 48:1.

[0041] The third aspect of this embodiment proposes the application of a polymer that improves the properties of polyamides, specifically polyamides, polybutylene terephthalate, polyethylene terephthalate, and polycarbonate, to enhance the wear resistance and toughness of the materials.

[0042] Example 2

[0043] The first aspect of this embodiment presents a polymer for improving the properties of polyamides, the second aspect presents a method for preparing the polymer for improving the properties of polyamides, and the third aspect presents an application of the polymer for improving the properties of polyamides. The specific raw materials and implementation methods are the same as in Example 1, except that the weight of high-density polyethylene is 15 parts.

[0044] Example 3

[0045] The first aspect of this embodiment presents a polymer for improving the properties of polyamides, the second aspect presents a method for preparing the polymer for improving the properties of polyamides, and the third aspect presents an application of the polymer for improving the properties of polyamides. The specific raw materials and implementation methods are the same as in Example 1, except that the high-density polyethylene is used in 25 parts by weight.

[0046] Example 4

[0047] The first aspect of this embodiment presents a polymer for improving the properties of polyamides, the second aspect presents a method for preparing the polymer for improving the properties of polyamides, and the third aspect presents an application of the polymer for improving the properties of polyamides. The specific raw materials and implementation methods are the same as in Example 1, except that glycidyl methacrylate is replaced with maleic anhydride.

[0048] Example 5

[0049] The first aspect of this embodiment presents a polymer for improving the properties of polyamides, the second aspect presents a method for preparing the polymer for improving the properties of polyamides, and the third aspect presents an application of the polymer for improving the properties of polyamides. The specific raw materials and implementation methods are the same as in Example 1, except that glycidyl methacrylate is replaced with acrylic acid.

[0050] Performance testing

[0051] 1. The polymer prepared in the examples was mixed with PA6 to obtain a mixture. The tensile strength, elongation at break, notched impact strength, and volume loss were tested according to GB / T 1303 standard, and the data are recorded in Table 1. The testing standards refer to relevant ASTM standards. The comparative example is PA6 without the polymer from the examples of this invention.

[0052] The test method for volume loss rate refers to GB / T 5478-2008. The test conditions (1) are as follows: grinding wheel type: CS-17; rotation speed: 60rpm; load: 1000g; wear resistance times: 200r; laboratory environment conditions: (23±2)℃, (50±5)%RH (humidity).

[0053] Table 1

[0054]

[0055] 2. The polymer prepared in Example 1 was mixed with PA66 to obtain a mixture. The mixture was then subjected to performance tests on the coefficient of friction, wear amount, and notched impact strength of the mixture, PA66, and PA66 with added polytetrafluoroethylene. The data are recorded in Table 2.

[0056] Test conditions (2) are as follows: anhydrous dry mixture; test conditions: 23℃; contact material: S45C; load: 0.75MPa; speed: 30m / min; sliding distance: 3km.

[0057] Table 2

[0058]

[0059]

Claims

1. A polymer for improving the properties of polyamides, characterized in that, The raw materials for preparation, by weight, include: 20-120 parts polyolefin, 0.1-1 parts initiator, 0.2-2 parts multifunctional monomer, and 0.1-1 parts antioxidant; The polyolefin is a compound of polyolefin I and polyolefin II, wherein polyolefin I is ultra-high molecular weight polyethylene with a melt index of 2-20 g / 10 min and a density of 0.96-0.97 g / cm³ at 190℃*10 kg. 3 Model L3000; Polyolefin II is high-density polyethylene, with a melt index of 5-10 g / 10 min at 190℃ and 2.16 kg, and model 5070; The weight ratio of polyolefin I to polyolefin II is (8-10):(0.1-2); The initiator is a compound of 2,5-dimethyl-2,5-(tert-butylperoxy)ethane and di(tert-butylperoxyisopropyl)benzene; the weight ratio of 2,5-dimethyl-2,5-(tert-butylperoxy)ethane and di(tert-butylperoxyisopropyl)benzene is 1:(0.1-2). The multifunctional monomer is selected from at least one of glycidyl methacrylate, maleic anhydride, and acrylic acid.

2. The polymer according to claim 1, characterized in that, The antioxidant is a compound of hindered phenolic antioxidants and phosphite antioxidants.

3. The polymer according to claim 2, characterized in that, The weight ratio of the hindered phenolic antioxidant to the phosphite antioxidant is (2-3):(1-1.5).

4. A method for preparing the polymer according to any one of claims 1-3, characterized in that, Includes the following steps: The polymer is obtained by mixing polyolefin, initiator, multifunctional monomer, and antioxidant, and then extruding and granulating the mixture through a twin-screw extruder.

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