A polyamide composition and its preparation method and application

Abstract

The invention discloses a polyamide composition, which comprises 50 parts of polyamide resin, 3-10 parts of silicon dioxide-coated zinc sulfide, weakly basic oxide, and perfluorobutyl sulfonate by weight, wherein the weight ratio of silicon dioxide-coated zinc sulfide: weakly basic oxide: perfluorobutyl sulfonate is 1: (0.02-0.5): (0.005-0.08), and the weakly basic oxide is greater than or equal to 0.1 parts, and the perfluorobutyl sulfonate is greater than or equal to 0.03 parts. The polyamide composition of the invention further improves color stability by using silicon dioxide-coated zinc sulfide to replace traditional zinc sulfide, and further, the specific compounding ratio of weakly basic oxide and perfluorobutyl sulfonate can also further improve the light stability of zinc sulfide.

Description

Technical Field

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

[0002] Modified polyamides are widely used in internal load-bearing parts or shell parts in industries such as rail transit, consumer electronics, power tools, and shared bicycles due to their excellent comprehensive properties such as good mechanical properties, chemical resistance, and heat resistance. At present, modified polyamide materials are increasingly used in outdoor products, such as railway track components, outdoor sporting goods, shared bicycles, and other application scenarios, which put forward more stringent requirements on the light aging resistance of the materials. Furthermore, as people's demand for the beauty of materials is increasing, we can currently encounter products of various colors on the market, among which white polyamide with high color stability also has a wide range of application needs. However, white polyamide is more susceptible to light aging than other colors.

[0003] At present, there are many technical solutions for high weather resistance polyamide reported in literature and patents, but there are few technical solutions for high color stability of white polyamide. Due to the color change of white pigments (such as zinc sulfide) under ultraviolet radiation, white polyamide materials are prone to yellowing, darkening and other color problems during long-term light aging or heat aging, resulting in excessive color difference. Summary of the invention

[0004] The purpose of the present invention is to overcome the above technical defects and provide a white polyamide composition resistant to long-term light aging.

[0005] The present invention is achieved through the following technical solutions:

[0006] A polyamide composition comprises, by weight, 50 parts of polyamide resin, 3-10 parts of silicon dioxide-coated zinc sulfide, weakly basic oxide, and perfluorobutyl sulfonate, wherein the weight ratio of silicon dioxide-coated zinc sulfide: weakly basic oxide: perfluorobutyl sulfonate is 1: (0.02-0.5): (0.005-0.08), and the weakly basic oxide is greater than or equal to 0.1 parts, and the perfluorobutyl sulfonate is greater than or equal to 0.03 parts. Preferably, the weight ratio of silicon dioxide-coated zinc sulfide: weakly basic oxide: perfluorobutyl sulfonate is 1: (0.1-0.3): (0.015-0.05).

[0007] 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.

[0008] The weakly alkaline oxide is selected from at least one of magnesium oxide and zinc oxide.

[0009] The perfluorobutyl sulfonate is selected from at least one of potassium perfluorobutyl sulfonate and lithium perfluorobutyl sulfonate.

[0010] The method of the present invention can prepare a product in which the amount of silicon dioxide coating accounts for 0.1-5.5% of the total weight. Preferably, the amount of silicon dioxide coating in the silicon dioxide coated zinc sulfide accounts for 0.3-5% of the total weight; more preferably, 1.5-3.3%. The silicon dioxide coated zinc sulfide is mainly obtained by reacting orthosilicate compounds on the surface of zinc sulfide under weak alkaline conditions to generate silicon dioxide to coat the zinc sulfide.

[0011] Silica-coated zinc sulfide can be prepared by the following method: dispersing zinc sulfide in 10-30 times of ethanol, dispersing by ultrasonic vibration, heating to 50-70°C, adding 0.1-0.5 times by weight (calculated as zinc sulfide) of deionized water while stirring; then, controlling the pH between 9 and 11 with ammonia water, adding orthosilicate compounds (which may be methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, butyl orthosilicate, etc.), after adding the orthosilicate compounds, continuously mechanically stirring at a speed of 200-300 rpm for 10-14 hours, the orthosilicate compounds react to generate silica, and the silica is coated on the surface of the zinc sulfide; after the stirring is completed, adding an appropriate amount of anhydrous alcohol solvent for washing 2-4 times, placing the powder in a vacuum drying oven, vacuum drying, after the drying is completed, filtering with a mesh sieve to remove the agglomerated powder, and obtaining silica-coated zinc sulfide. The coating weight ratio of silicon dioxide can be adjusted by changing the addition ratio of zinc sulfide and orthosilicate compounds.

[0012] You can choose whether to add a certain amount of additives according to actual needs. The additives can be antioxidants, lubricants, flame retardants, etc.

[0013] The preparation method of the polyamide composition of the present invention comprises the following steps: according to the proportion, polyamide resin, ultraviolet light absorber, light stabilizer, weak alkaline oxide, perfluorobutyl sulfonate and silicon dioxide coated zinc sulfide are uniformly mixed, and then extruded and granulated by a twin-screw extruder, glass fiber is fed sideways, the temperature range is 180-320 DEG C, and the rotation speed range is 200-700 rpm to obtain the polyamide composition.

[0014] The polyamide composition of the present invention is used to prepare outdoor products, such as internal stress-bearing parts or outer shell parts in industries such as rail transportation, consumer electronics, electric tools, and shared bicycles.

[0015] The present invention has the following beneficial effects:

[0016] The present invention uses silicon dioxide to coat zinc sulfide, which can improve the discoloration of zinc sulfide due to radiation, and further improves the light aging discoloration resistance of zinc sulfide by compounding weak alkaline oxides and perfluorobutyl sulfonate. After the polyamide composition of the present invention is subjected to a xenon lamp aging test (UV aging for 1000 hours according to GB / T 16422.3 cycle 1 conditions), ΔE is less than 4.0. DETAILED DESCRIPTION

[0017] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0018] The sources of raw materials used in the present invention are as follows:

[0019] PA6: PA6 HY2800A, Haiyang Chemical Fiber;

[0020] PA66: PA66 U4800 NC01 SS, INVISTA;

[0021] PA610: PA610 F120, Shandong Guangyin;

[0022] PA10T: KFHP12, Kingfa Science & Technology Co., Ltd.;

[0023] Magnesium oxide: KYOWAMAG 30, Kyowa Industry Co., Ltd., Japan;

[0024] Zinc oxide: analytical grade, Aladdin Company;

[0025] Magnesium hydroxide: analytical grade, Aladdin Company;

[0026] Zinc hydroxide: analytical grade, Aladdin Company;

[0027] Potassium perfluorobutanesulfonate: PFBS-A, Shanghai Roger Technology Co., Ltd.

[0028] The following zinc sulfide was purchased from Sachliben, Germany, brand HD-S;

[0029] Zinc sulfide A: Silica-coated zinc sulfide, homemade, with silica coating accounting for 0.3% of the total weight;

[0030] Zinc sulfide B: Silica-coated zinc sulfide, homemade, with silica coating accounting for 1.5% of the total weight;

[0031] Zinc sulfide C: Silica-coated zinc sulfide, homemade, with silica coating accounting for 3.3% of the total weight;

[0032] Zinc sulfide D: Silica-coated zinc sulfide, homemade, with silica coating accounting for 4.8% of the total weight;

[0033] Zinc sulfide E: Silica-coated zinc sulfide, homemade, with silica coating accounting for 0.1% of the total weight;

[0034] Zinc sulfide F: Silica-coated zinc sulfide, homemade, with silica coating accounting for 5.5% of the total weight;

[0035] Zinc sulfide G: ordinary zinc sulfide, zinc sulfide HD-S, Germany Shahaliben;

[0036] The preparation method of the polyamide composition of the embodiments and comparative examples is as follows: polyamide resin, weak alkaline oxide (or magnesium hydroxide, zinc hydroxide), perfluorobutane sulfonate, and silica-coated zinc sulfide (or zinc sulfide) are uniformly mixed according to the ratio, and then extruded and granulated by a twin-screw extruder with glass fiber side feeding, the temperature range is 180-320°C, and the rotation speed range is 200-700 rpm to obtain a polyamide composition.

[0037] Various test methods:

[0038] The polyamide composition is placed in a blast oven at 120° C. for 4 hours and then injection molded into a color plate with a thickness of 2.5 mm at an injection molding temperature of 250-290° C.;

[0039] Color value difference ΔE test: Use Color-Eye 7000A colorimeter, according to GB / T 3979:2008 standard, select D65 light source for color measurement, the measured L value represents the brightness of the object surface, the a value represents the red-green range of the object surface, and the b value represents the yellow-blue range of the object surface; the L value can be used as a reference for whiteness, where the larger the L value, the lighter the color. Then put the square plate into the xenon lamp aging test box, and perform ultraviolet aging for 1000 hours according to GB / T 16422.3 cycle 1 conditions, then take it out and test the color value after aging according to the above method. The calculation method of color difference value ΔE is: ΔE=[(ΔL) 2 + (Δa*) 2 +(Δb) 2 ] 1 / 2 , where ΔL, Δa and Δb are the changes in L value, a value and b value before and after aging.

[0040] Table 1: Contents of components (parts by weight) and test results of polyamide compositions of Examples 1-6

[0041] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 PA6 50 50 50 PA66 50 PA610 50 PA10T 50 Zinc Sulfide A 5 5 5 5 3 10 Magnesium Oxide 1 1 1 1 0.15 Zinc Oxide 0.2 Potassium perfluorobutanesulfonate 0.15 0.15 0.15 0.15 0.03 0.2 ΔE after aging 3.2 3.3 3.5 3.1 3.7 3.8

[0042] Table 2: Content of each component (parts by weight) and test results of polyamide compositions of Examples 7-10

[0043] Example 7 Example 8 Example 9 Example 10 PA6 50 50 50 50 Zinc Sulfide A 5 5 5 5 Magnesium Oxide 0.1 0.5 1.5 2.5 Potassium perfluorobutanesulfonate 0.015 0.075 0.25 0.4 ΔE after aging 3.9 3.3 3.3 3.6

[0044] It can be seen from Examples 1 / 7-10 that the preferred weight ratio of silicon dioxide-coated zinc sulfide:weakly basic oxide:perfluorobutane sulfonate is 1:(0.1-0.3):(0.015-0.05) and ΔE is smaller.

[0045] Table 3: Content of each component (parts by weight) and test results of polyamide compositions of Examples 11-15

[0046] Embodiment 11 Example 12 Example 16 Embodiment 14 Embodiment 15 PA6 50 50 50 50 50 Magnesium Oxide 1 1 1 1 1 Potassium perfluorobutanesulfonate 0.15 0.15 0.15 0.15 0.15 Zinc sulfide B 5 Zinc Sulfide C 5 Zinc sulfide D 5 Zinc Sulfide E 5 Zinc Sulfide F 5 ΔE after aging 3.0 2.9 3.4 3.5 3.8

[0047] It can be seen from Examples 1 / 11-15 that the ΔE is lower at the preferred silica coating amount.

[0048] Table 4: Content of each component (parts by weight) and test results of the comparative polyamide composition

[0049] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 PA6 50 50 50 50 50 50 50 Magnesium Oxide 0.5 1 0.06 3 Potassium perfluorobutanesulfonate 0.3 0.15 0.015 0.5 Zinc Sulfide A 5 5 5 3 5 Zinc sulfide G 5 5 ΔE after aging 6.1 6.6 4.9 4.6 4.7 4.6 4.2

[0050] From the comparison between Comparative Example 1 / 2 and Comparative Example 3 / Example, it can be seen that the combination of weakly alkaline oxide: perfluorobutane sulfonate can more significantly improve the light aging resistance of silicon dioxide-coated zinc sulfide.

[0051] It can be seen from Comparative Examples 4-7 that if the compounding ratio of silicon dioxide-coated zinc sulfide: weakly alkaline oxide: perfluorobutane sulfonate is not within the scope of the present invention, it is difficult to control ΔE below 4.0.

[0052] The following experimental examples illustrate that in the technical solution of the present invention, the compounding of weakly alkaline oxide and perfluorobutyl sulfonate mainly improves the light aging resistance of zinc sulfide, but has no significant effect on the light aging resistance of the resin matrix.

[0053] UV absorber: Tinuvin® 360, BASF, CAS No.: 103597-45-1;

[0054] Light stabilizer: Tinuvin® 770, CAS No.: 52829-07-9;

[0055] Gloss test: Use the above 2.5mm thick color plate for testing, and randomly test 10 points to get the average value; BYK gloss meter, measuring angle 60°; Aging conditions: Put the square plate into the xenon lamp aging test box, and perform UV aging for 1000 hours according to GB / T 16422.3 cycle 1 conditions, then take it out, and then test the gloss and color value after aging according to the above method. The calculation method of surface gloss retention rate is: (initial surface gloss - surface gloss after aging) / initial surface gloss × 100%.

[0056] Table 5: Test examples

[0057] Example 1 Experimental example PA6 50 50 UV absorber - 1 Light Stabilizer - 0.8 Magnesium Oxide 0.6 0.6 Potassium perfluorobutanesulfonate 0.3 0.2 Zinc Sulfide A 5 - Initial surface gloss, GU 82 85 Surface gloss retention rate / % 45.6 84.7 ΔE after aging 3.2 4.3

[0058] The surface gloss of the polyamide composition is mainly affected by the resin matrix. After light aging, the resin matrix deteriorates, resulting in a low surface gloss retention rate. The UV absorber / light stabilizer mainly inhibits the light aging of the resin matrix, so the gloss retention rate of the test example is high.

Claims

1. A polyamide composition, characterized in that The invention comprises 50 parts of polyamide resin, 3-10 parts of silicon dioxide coated zinc sulfide, weak alkaline oxide and perfluorobutyl sulfonate by weight, wherein the weight ratio of silicon dioxide coated zinc sulfide: weak alkaline oxide: perfluorobutyl sulfonate is 1: (0.02-0.5): (0.005-0.08), and the weak alkaline oxide is greater than or equal to 0.1 parts, and the perfluorobutyl sulfonate is greater than or equal to 0.03 parts; the weak alkaline oxide is selected from at least one of magnesium oxide and zinc oxide; and the perfluorobutyl sulfonate is selected from at least one of potassium perfluorobutyl sulfonate and lithium perfluorobutyl sulfonate.

2. The polyamide composition according to claim 1, characterized in that The weight ratio of silica-coated zinc sulfide:weakly basic oxide:perfluorobutanesulfonate is 1:(0.1-0.3):(0.015-0.05).

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

4. The polyamide composition according to claim 3, characterized in that The amount of silicon dioxide coated in the silicon dioxide coated zinc sulfide accounts for 1.5-3.3% of the total weight.

5. The polyamide composition according to claim 1, characterized in that 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.

6. The polyamide composition according to claim 1, characterized in that By weight, 0-1 part of lubricant is also included.

7. The method for preparing the polyamide composition according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: according to a proportion, polyamide resin, weak alkaline oxide, perfluorobutyl sulfonate and silicon dioxide coated zinc sulfide are uniformly mixed, and then extruded and granulated by a twin-screw extruder at a temperature range of 180-320°C and a rotation speed range of 200-700 rpm to obtain a polyamide composition.

8. Use of the polyamide composition according to any one of claims 1 to 6, characterized in that: For the preparation of outdoor products.