A polyamide composition, its preparation method and application

Abstract

This invention discloses a polyamide composition comprising, by weight, the following components: 50 parts polyamide resin; 1-10 parts silica-coated zinc sulfide; 20-50 parts ethylene-methacrylate ionomer; and 0.002-0.020 times the weight of the ethylene-methacrylate ionomer as a benzofuranone carbon radical scavenger. This invention, by using silica-coated zinc sulfide as a whitening agent and employing a benzofuranone carbon radical scavenger, significantly improves color stability, as both the silica-coated zinc sulfide and the benzofuranone carbon radical scavenger tend to disperse within the ethylene-methacrylate ionomer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a polyamide composition, a preparation method and application thereof. BACKGROUND

[0002] Modified polyamides are widely used in internal force components or shell components of rail transit, consumer appliances, power tools, shared bicycles and other industries due to their excellent comprehensive properties such as good mechanical properties, chemical resistance and heat resistance. At present, reinforced polyamide materials are increasingly used in outdoor products, such as railway track components, outdoor sports products, shared bicycles and other application scenarios, which puts forward more stringent requirements on the light aging resistance and high temperature resistance of the materials. As people's demand for material aesthetics is increasing, we can encounter a variety of colored products on the market, and there is a wide application demand for reinforced polyamides with high whiteness.

[0003] At present, many high-weather-resistant polyamide technical solutions are reported in the literature and patents, but there are few technical solutions about the thermal oxidation color stability of white polyamide. Since polyamide materials have active amide groups, white polyamide materials are prone to color problems such as yellowing and darkening during long-term thermal oxidation, resulting in large color difference changes. SUMMARY

[0004] The purpose of the present application is to provide a polyamide composition with long-term color stability.

[0005] The present application is realized by the following technical solutions:

[0006] A polyamide composition, by weight, comprises the following components:

[0007] Polyamide resin 50 parts;

[0008] Silicon dioxide coated zinc sulfide 1-10 parts;

[0009] Ethylene-methacrylic acid ionomer 20-50 parts;

[0010] Benzofuranone carbon radical scavenger 0.002-0.020 times the weight of ethylene-methacrylic acid ionomer.

[0011] The benzofuranone carbon radical scavenger is selected from at least one of 4-tert-butyl-2(5-tert-butyl-2-oxo-3-hydro-benzofuran-3-yl)phenyl 3,5-di-tert-butyl-4-hydroxybenzoate (CAS No. 1261240-30-5) and 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)benzofuran-2(3H)-one (CAS No. 164391-52-0).

[0012] Preferably, the weight of the benzofuranone carbon radical scavenger is 0.008-0.017 times, more preferably 0.010-0.015 times, the weight of the ethylene-methacrylic acid ionomer. Within the preferred weight ratio range, the proportion of benzofuranone carbon radical scavenger distributed in the ethylene-methacrylic acid ionomer is higher, and if the weight ratio of benzofuranone carbon radical scavenger is too high, the color stability tends to be flat.

[0013] The amount of silica coating in the silica-coated zinc sulfide is 0.3-5% of the total weight; preferably 1.5-3.3%.

[0014] The silica-coated zinc sulfide is mainly coated by reacting orthosilicate compounds on the surface of zinc sulfide under weak alkaline conditions to form silica.

[0015] The silica-coated zinc sulfide can be made according to the following method: disperse the zinc sulfide into 10-30 times the weight of ethanol, disperse with ultrasonic oscillation, heat to 50-70℃, add 0.1-0.5 times the weight of deionized water (based on zinc sulfide) while stirring; then, control the PH between 9-11 with ammonia water, and then add orthosilicate compounds (which can be methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, butyl orthosilicate, etc.), after adding the orthosilicate compound, continuously stir at a speed of 200-300 rpm for 10-14 hours, the orthosilicate compound reacts to form silica, which coats the surface of the zinc sulfide; after stirring, wash the powder with an appropriate amount of anhydrous alcohol solvent for 2-4 times, place the powder in a vacuum drying oven, vacuum dry, after drying, screen filter, remove the agglomerated powder, and obtain the silica-coated zinc sulfide. The coating weight ratio of silica can be adjusted by changing the addition amount ratio of zinc sulfide and orthosilicate compound.

[0016] The ethylene-methacrylic acid ionomer refers to a derivative of an ethylene-methacrylic acid copolymer in which part of the acrylic acid functional groups are neutralized by metal cations. Optionally, the metal cations are zinc ions, sodium ions, or potassium ions.

[0017] The melting point of the ethylene-methacrylic acid ionomer is in the range of 65-95℃, preferably 85-95℃, measured according to the ISO 11357-1-2016 standard.

[0018] The polyamide is selected from at least one of PA56, PA510, PA66, PA610, PA612, PA1010, PA1012, PA1212, PA6, PA7, PA11, PA12, PA6T, PA10T, PA MXD6, and PA MXD10.

[0019] The lubricant can be added according to actual needs, and can be at least one of a stearate lubricant, a fatty acid lubricant and a stearate ester lubricant; the stearate lubricant is at least one of calcium stearate, magnesium stearate and zinc stearate; the fatty acid lubricant is at least one of a fatty acid, a fatty acid derivative and a fatty acid ester; and the stearate ester lubricant is at least one of pentaerythritol stearate.

[0020] The preparation method of the polyamide composition comprises the following steps: uniformly mixing the polyamide resin, the carbon radical capturing agent and the silica-coated zinc sulfide according to the proportions, and then extruding and granulating through a double-screw extruder at a temperature range of 180-320 DEG C and a rotation speed range of 200-700 r / min to obtain the polyamide composition.

[0021] The polyamide composition of the present application is used for preparing the shell of an outdoor product.

[0022] The present application has the following beneficial effects

[0023] On the one hand, the present application can improve the heat aging color stability of zinc sulfide by coating the surface of zinc sulfide with silica. Embodiment

[0024] The present application will be described in detail below in combination with specific examples. The following examples will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present application. These all belong to the protection scope of the present application.

[0025] The raw materials used in the present application are as follows:

[0026] PA6: PA6 HY2800A, Haiyang Chemical Fiber;

[0027] PA66: PA66 U4800 NC01 SS, Ineos;

[0028] PA610: PA610 F120, Shandong Guangyin;

[0029] PA MXD6: PA MXD6, Yinfuzheng Chemical Industry Co., Ltd.

[0030] Ethylene-Zinc Methacrylate Ionomer A: Surlyn 9910, DuPont, melting point 86℃;

[0031] Ethylene-Sodium Methacrylate Ionomer B: Surlyn 8920, DuPont, melting point 90℃;

[0032] Ethylene-Zinc Methacrylate Ionomer C: Surlyn 9120, DuPont, melting point 86℃;

[0033] Ethylene-Zinc Methacrylate Ionomer D: Surlyn 9320, DuPont, melting point 70℃;

[0034] Carbon radical scavenger A: 4-tert-butyl-2(5-tert-butyl-2-oxo-3-hydro- benzofuran-3-yl)phenyl 3,5-di-tert-butyl-4-hydroxybenzoate, CAS: 1261240-30-5, commercially available.

[0035] Carbon radical scavenger B: 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)benzofuran- 2(3H)-one CAS: 164391-52-0, commercially available.

[0036] Carbon radical scavenger C: Hydroxylamine, Bis(octadecyl)hydroxylamine, CAS: 143925-92-2, commercially available.

[0037] Carbon radical scavenger D: Bisphenol monoacrylate, 2-tert-butyl-6-(3-tert-butyl-2- hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, CAS: 61167-58-6, commercially available.

[0038] Other antioxidant A: CAS: 10081-67-1, amine antioxidant, commercially available;

[0039] Other antioxidant B: CAS: 23128-74-7, hindered phenol antioxidant, commercially available;

[0040] Other antioxidant C: CAS: 31570-04-4, phosphite antioxidant, commercially available;

[0041] The following zinc sulfide was purchased from Sachtleben Chemie, Germany, with the trade name HD-S;

[0042] Silica-coated zinc sulfide A: self-made, with a silica coating amount of 0.3% of the total weight;

[0043] Silica-coated zinc sulfide B: self-made, with a silica coating amount of 1.5% of the total weight;

[0044] Silica coated zinc sulfide C: self-made, silica coating amount is 3.3% of the total weight;

[0045] Silica coated zinc sulfide D: self-made, silica coating amount is 4.8% of the total weight;

[0046] Silica coated zinc sulfide E: self-made, silica coating amount is 0.1% of the total weight;

[0047] Silica coated zinc sulfide F: self-made, silica coating amount is 5.5% of the total weight;

[0048] Common zinc sulfide: zinc sulfide HD-S, Sachtleben, Germany;

[0049] Lubricant: LOXIOL G32, Ems-Chek, Germany.

[0050] Preparation method of polyamide composition of examples and comparative examples: polyamide resin, carbon radical trapping agent, silica coated zinc sulfide are mixed uniformly, and then extruded and granulated through a double screw extruder, the temperature range is 180-320℃, and the rotation speed range is 200-700 revolutions / minute, to obtain the polyamide composition.

[0051] Test methods:

[0052] (1) Color stability: the notched impact sample and the square plate are put into a xenon lamp aging test box, and are subjected to xenon arc lamp aging for 1000h according to ISO 4892-2:2013 CYCLE1 condition, then are taken out, the notched impact sample and the square plate after aging are required to be baked in an oven at 120℃ for 8h to ensure sufficient removal of moisture, and then are tested for IZOD notched impact strength after adjustment according to the above method. The calculation method of notched impact strength retention rate is: (initial notched impact strength- notched impact strength after aging) / initial notched impact strength x 100%; the calculation method of surface gloss retention rate is: (initial surface gloss- surface gloss after aging) / initial surface gloss x 100%.

[0053] Table 1: content of each component of polyamide composition of examples 1-6 (weight parts) and test results

[0054] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 PA6 50 50 50 PA66 50 PA610 50 PA10T 50 Silica coated zinc sulfide A 4 1 8 10 4 4 Ethylene-methacrylic acid ionomer A 30 25 20 50 30 30 Carbon radical scavenger A 0.3 0.25 0.2 0.4 0.06 0.24 Lubricant 0.5 Delta E after aging 2.3 2.5 2.4 2.1 2.7 2.4

[0055] As can be seen from examples 1 / 6-9, under the preferred ratio of ethylene-methacrylic acid ionic polymer / benzofuranone carbon radical trapping agent, the ΔE after aging can be controlled to be ≤2.4, and the cost is lower, while the decrease of ΔE by increasing the complex ratio of benzofuranone carbon radical trapping agent tends to be flat, and the cost is higher.

[0056] Table 2: Composition of polyamide compositions of Examples 7-12 (parts by weight) and test results

[0057] Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 PA6 50 50 50 50 50 50 Silica coated zinc sulfide A 4 4 4 4 4 4 Ethylene-methacrylic acid ionomer A 30 30 30 Ethylene-methacrylic acid ionomer B 30 Ethylene-methacrylic acid ionomer C 30 Ethylene-methacrylic acid ionomer D 30 Carbon radical scavenger A 0.45 0.51 0.6 0.3 0.3 0.3 Delta E after aging 2.3 2.3 2.2 2.2 2.3 2.5

[0058] From Examples 1 / 10-12, it is preferred that the melting point of the ethylene-methacrylic acid ionomer polymer is in the range of 85-95°C.

[0059] Table 3: Composition of polyamide compositions of Examples 13-18 (parts by weight) and test results

[0060] Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 PA6 50 50 50 50 50 50 Silica coated zinc sulfide B 4 4 Silica coated zinc sulfide C 4 Silica coated zinc sulfide D 4 Silica coated zinc sulfide E 4 Silica coated zinc sulfide F 4 Ethylene-methacrylic acid ionomer A 30 30 30 30 30 30 Carbon radical scavenger A 0.3 0.3 0.3 0.3 0.3 Carbon radical scavenger B 0.3 Delta E after aging 2.2 2.1 2.4 2.7 2.5 2.3

[0061] From Examples 1 / 13-7, it is preferred that the amount of silica coated in the silica coated zinc sulfide is in the range of 0.3-5% of the total weight, more preferably 1.5-3.3%.

[0062] Table 4: Composition of polyamide compositions of Comparative Examples 1-8 (parts by weight) and test results

[0063] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 PA6 50 50 50 50 50 50 50 50 Silica coated zinc sulfide A 4 4 4 4 4 4 4 Common zinc sulfide 4 Ethylene-methacrylic acid ionomer A 30 0 10 60 30 30 30 Carbon radical scavenger A 0.3 0.3 0.3 0.3 0 0.03 0.9 Delta E after aging 4.1 4.2 3.4 3.1 3.8 3.3 3.6 4.8

[0064] From Comparative Example 1, it is known that ordinary zinc sulfide has poor light aging resistance.

[0065] From Comparative Examples 2 / 3, it is known that without ethylene-methacrylic acid ionomer polymer or with insufficient content, the light aging resistance of zinc sulfide is not significantly improved.

[0066] From Comparative Example 4, it is known that if the content of ethylene-methacrylic acid ionomer polymer is too high, the light aging resistance is actually reduced.

[0067] From Comparative Examples 5-6, it is known that if the content of carbon radical scavenger is insufficient, the light aging resistance is not good.

[0068] From Comparative Example 7, it is known that if the amount of carbon radical scavenger is too high, yellowing occurs.

[0069] Table 5: Composition of polyamide compositions of Comparative Examples 9-13 (parts by weight) and test results

[0070] Comparative Example 9 Comparative Example 10 Comparative Example 11 Comparative Example 12 Comparative Example 13 PA6 50 50 50 50 50 Silica coated zinc sulfide A 4 4 4 4 4 Ethylene-methacrylic acid ionomer A 30 30 30 30 30 Carbon radical scavenger C 0.3 Carbon radical scavenger D 0.3 Other antioxidant A 0.3 Other antioxidant B 0.3 Other antioxidant C 0.3 Delta E after aging 3.3 3.1 3.6 3.5 4.0

[0071] From Comparative Examples 9-13, it is known that other types of antioxidants cannot replace carbon radical scavengers.

Claims

1. A polyamide composition characterized in that, by weight, comprising: a polyamide resin 50 parts; silica-coated zinc sulfide 1-10 parts; ethylene-methacrylic acid ionomer 20-50 parts; a benzofuranone carbon radical scavenger 0.002-0.020 times the weight parts of the ethylene-methacrylic acid ionomer.

2. The polyamide composition according to claim 1, characterized in that, The benzofuranone carbon radical scavenger is at least one selected from 4-tert-butyl-2(5-tert-butyl-2-oxo-3-hydro-benzofuran-3-yl)phenyl 3,5-di-tert-butyl-4-hydroxybenzoate, 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)benzofuran-2(3H)-one.

3. The polyamide composition according to claim 1, characterized in that, The weight parts of the benzofuranone carbon radical scavenger is 0.008-0.017 times the weight parts of the ethylene-methacrylic acid ionomer.

4. The polyamide composition according to claim 3, characterized in that, The weight parts of the benzofuranone carbon radical scavenger is 0.010-0.015 times the weight parts of the ethylene-methacrylic acid ionomer.

5. The polyamide composition according to claim 1, characterized in that, The silica-coated amount in the silica-coated zinc sulfide accounts for 0.3-5% of the total weight.

6. The polyamide composition according to claim 5, characterized in that, The silica-coated amount in the silica-coated zinc sulfide accounts for 1.5-3.3% of the total weight.

7. The polyamide composition according to claim 1, characterized in that, The melting point of the ethylene-methacrylic acid ionomer ranges from 65-95℃, measured according to the ISO 11357-1-2016 standard.

8. The polyamide composition according to claim 7, characterized in that, The melting point of the ethylene-methacrylic acid ionomer ranges from 85-95℃, measured according to the ISO 11357-1-2016 standard.

9. The polyamide composition according to claim 1, characterized in that, The polyamide is at least one selected from PA56, PA510, PA66, PA610, PA612, PA1010, PA1012, PA1212, PA6, PA7, PA11, PA12, PA6T, PA10T, PA MXD6, PA MXD10.

10. The polyamide composition according to claim 1, characterized in that, It further comprises 0-1 parts of a lubricant by weight.

11. Process for the production of the polyamide composition according to any one of claims 1 to 10, characterized in that, The method comprises the following steps: mixing the components uniformly according to the proportions, and then extruding and granulating through a twin-screw extruder, with a temperature range of 180-320℃ and a rotation speed range of 200-700 revolutions / minute, to obtain a polyamide composition.

12. Use of the polyamide composition according to any one of claims 1 to 10, characterized in that The method is used for preparing an outer shell of an outdoor product. The method is used for preparing an outer shell of an outdoor product.