A nylon composition, its preparation and use

Abstract

The application discloses a nylon composition and a preparation method and application thereof, and belongs to the technical field of engineering plastics. Specifically, the nylon composition comprises the following components in parts by weight: 24-82.5 parts of PA resin; 10-50 parts of glass fiber; 0.5-2 parts of sodium lignosulfonate; and 7-23 parts of halogen-free flame retardant. The application can be used for preparing electrical management components or electric tools. The nylon composition provided by the application has the effects of low mold fouling, moisture and heat aging resistance and ultraviolet resistance. The application uses a by-product lignin in the papermaking industry, reduces the cost of the material, and realizes waste utilization.

Description

Technical Field

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

[0002] Halogen-free flame-retardant glass fiber reinforced polyamide (PA) refers to polyamide materials that do not contain halogen elements (such as chlorine, bromine, etc.) and possess flame-retardant properties. Halogen-free flame-retardant polyamides typically achieve their flame-retardant effect by adding flame retardants containing elements such as phosphorus and nitrogen. These flame retardants release flame-retardant gases or form a protective film during combustion, thereby reducing the material's flammability. Simultaneously, these materials do not produce toxic halogen compounds during combustion, thus exhibiting good environmental friendliness and safety. Halogen-free flame-retardant glass fiber reinforced polyamide combines the excellent properties of polyamide, the reinforcing effect of glass fiber, and the safety of halogen-free flame retardants. With its environmentally friendly flame-retardant properties, excellent mechanical properties, and good heat resistance, it is widely used in fields such as electronics, automotive, aerospace, rail transportation, and construction.

[0003] Despite the numerous advantages and applications of polyamides, outdoor products typically require materials with good UV resistance and resistance to damp heat aging. PA itself has poor UV resistance, and the addition of halogen-free flame retardants accelerates PA aging in humid and hot environments, resulting in significant color changes, decreased mechanical properties, and negatively impacting the aesthetics and usability of polyamide products.

[0004] Lignin sulfonate, also known as sulfonated lignin, is a multi-component polymeric anionic surfactant extracted from wood, mainly obtained as a byproduct of sulfite pulping. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical problems and provide a nylon composition that overcomes the defects of halogen-free flame retardants causing accelerated aging of polyamide systems in humid and hot environments, large color changes and decreased mechanical properties of polyamide systems. The nylon composition provided by this invention has the characteristics of low fouling, resistance to humid and hot aging, and UV resistance.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned nylon composition.

[0007] Another object of the present invention is to provide applications of the above-described nylon composition.

[0008] This invention is achieved through the following technical solution:

[0009] A nylon composition comprises the following components in parts by weight:

[0010] 24-82.5 parts of PA resin;

[0011] 10-50 parts glass fiber;

[0012] Sodium lignosulfonate 0.5-2 parts;

[0013] 7-23 parts of halogen-free flame retardant;

[0014] Among them, sodium lignosulfonate has a sulfonation degree of 1.0-1.2 mmol / g and a weight-average molecular weight of 10,000-14,000 Da.

[0015] Preferably, the amount of sodium lignosulfonate added is 1-2 parts by weight.

[0016] Tests have shown that sodium lignosulfonate has good UV resistance and can neutralize the acidity of halogen-free flame retardants, improve the UV aging resistance and damp heat aging resistance of halogen-free flame-retardant glass fiber reinforced polyamide, and effectively reduce mold scale weight.

[0017] When the degree of sulfonation is too low, the hydrophilicity of sodium lignosulfonate decreases, making it difficult to migrate to the surface during UV resistant processes and affecting its UV protection effect. When the degree of sulfonation is too high, the hydrophilicity of sodium lignosulfonate increases, making it easy to precipitate to the surface during humid heat aging and failing to neutralize the flame retardant. When the molecular weight is too low, sodium lignosulfonate easily precipitates to the surface and fails to neutralize the flame retardant during humid heat aging. When the molecular weight is too high, sodium lignosulfonate is not easily dispersed and has difficulty migrating to the surface, affecting its UV protection effect.

[0018] Preferably, the PA resin is selected from any one or more of nylon 6, nylon 66, or copolymers of nylon 6 and nylon 66.

[0019] Preferably, the PA resin has a mass percentage content of not less than 20% in the nylon composition.

[0020] Preferably, the glass fiber is selected from short-cut fibers treated with a silane coupling agent containing amino or epoxy functional groups.

[0021] Preferably, the halogen-free flame retardant is selected from phosphorus-nitrogen-based halogen-free flame retardants.

[0022] Specifically, the phosphorus-nitrogen-based halogen-free flame retardant is selected from any one or more of red phosphorus, diethyl aluminum hypophosphite, melamine polyphosphate, or melamine cyanurate.

[0023] Those skilled in the art may add 0.01-2 parts by weight of processing aids as needed, wherein the aids are selected from any one or more of antioxidants or lubricants.

[0024] Preferably, the antioxidant is selected from any one or more of hindered phenols, phosphites, or thiophosphates; and the lubricant is selected from any one or more of oxidized polyethylene wax, ethylene bis-fatty acid amide, or pentaerythritol stearate.

[0025] The present invention also provides a method for preparing the above-mentioned nylon composition, characterized by comprising the following steps:

[0026] M1: Dry the PA resin, mix the dried PA resin and other components except glass fiber according to the formula, and put the mixture into the main feed hopper of the twin-screw extruder;

[0027] M2: The glass fiber is fed into the side feed hopper of the twin-screw extruder;

[0028] M3: Set the temperature of each zone of the twin-screw extruder to 230-280℃, the feed rate to 300-500kg / h, and the main machine speed to 300-400rpm;

[0029] M4: The melt is extruded through an extruder, cooled, and air-dried to obtain a nylon composition.

[0030] The present invention also provides the application of the above-described nylon composition, characterized in that it is used to prepare electrical management components or power tools.

[0031] The present invention has the following beneficial effects:

[0032] Compared with the prior art, the nylon composition prepared by the present invention can simultaneously meet the following requirements: injection molding fouling is less than 0.025g; tensile strength retention rate is more than 50% after damp heat aging test; and color difference before and after UV aging test is less than 5%.

[0033] Tests have shown that sodium lignosulfonate exhibits excellent UV resistance and can neutralize the acidity of halogen-free flame retardants, improving the UV aging resistance and damp heat aging resistance of halogen-free flame-retardant glass fiber reinforced polyamide. Furthermore, the addition of sodium lignosulfonate can effectively reduce mold fouling weight. This invention utilizes lignin, a byproduct of the papermaking industry, reducing material costs and turning waste into treasure. Detailed Implementation

[0034] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0035] The raw materials used in this invention are sourced from:

[0036] PA Resin 1: Nylon 6, grade PA6 BE3270, Jiangsu Hongsheng.

[0037] PA Resin 2: Nylon 66, grade PA66 EPR24, Chongqing Huafeng.

[0038] PA Resin 3: Nylon 66 / 6 copolymer, grade M093G02, Xinhui Meida.

[0039] Fiberglass 1: ECS10-3.0-568H, China Jushi.

[0040] Glass fiber 2: HM435TM-10-3.0, Taishan Glass Fiber.

[0041] Sodium lignin sulfonate was prepared in-house by reacting alkali lignin with different amounts of sodium sulfite under alkaline conditions to introduce sulfonic acid groups, thereby obtaining lignin with different degrees of sulfonation. The sulfur content of alkali lignin and sulfonated alkali lignin was determined by elemental analysis, and the degree of sulfonation was calculated. Furthermore, lignin with different molecular weights was prepared by alkyl bridging.

[0042] The alkali lignin used to prepare sodium lignin sulfonate was purchased from Xiangjiang River in Hunan Province. After preparing sodium lignin sulfonate by the sulfite process, it was washed, dialyzed, rotary evaporated and freeze-dried to obtain the following sodium lignin sulfonate raw material.

[0043] Sodium lignosulfonate 1: sulfonation degree 1.06 mmol / g, weight average molecular weight 10473 Da.

[0044] Sodium lignosulfonate 2: sulfonation degree 1.11 mmol / g, weight average molecular weight 12654 Da.

[0045] Sodium lignosulfonate 3: sulfonation degree 1.15 mmol / g, weight average molecular weight 11891 Da.

[0046] Sodium lignosulfonate 4: sulfonation degree 1.10 mmol / g, weight average molecular weight 13562 Da.

[0047] Sodium lignosulfonate 5: sulfonation degree 1.42 mmol / g, weight average molecular weight 12477 Da.

[0048] Sodium lignosulfonate 6: sulfonation degree 0.76 mmol / g, weight average molecular weight 12612 Da.

[0049] Sodium lignosulfonate 7: sulfonation degree 1.08 mmol / g, weight average molecular weight 16378 Da.

[0050] Sodium lignosulfonate 8: sulfonation degree 1.14 mmol / g, weight average molecular weight 8270 Da.

[0051] Calcium lignosulfonate: sulfonation degree is about 1.13 mmol / g, and weight-average molecular weight is about 12732 Da.

[0052] Magnesium lignosulfonate: sulfonation degree approximately 1.15 mmol / g, weight-average molecular weight approximately 12213 Da.

[0053] Halogen-free flame retardant 1: Diethylaluminum hypophosphite, grade OP1230, Clariant.

[0054] Halogen-free flame retardant 2: melamine polyphosphate, brand name BUDIT 342, Budenheim.

[0055] Halogen-free flame retardant 3: Red phosphorus, grade FR9950T, red phosphorus masterbatch, red phosphorus content 50%, same process.

[0056] Halogen-free flame retardant 4: Melamine cyanurate, brand name MCA-01, Sichuan Fine Chemicals.

[0057] Antioxidant 1: RIANOX 1010.

[0058] Antioxidant 2: RIANOX 168.

[0059] Lubricant: LOXIOL® P 861 / 3.5, Emery Oleochemicals GmbH.

[0060] Test methods:

[0061] The nylon composition prepared by the present invention was dried in a dehumidifying drying oven at 120°C for 4 hours.

[0062] (1) Mold scale test: The weight of mold scale on the material was determined using the patented equipment CN216544417U. The injection molding machine temperature was 290℃. After 200 injections, the weight difference ΔM of the scale before and after injection was measured, in g.

[0063] (2) Moist heat aging test: The tensile specimens were injection molded according to ISO 527-2 standard. The specimens were placed in an aging chamber at 85℃ and 85%RH for 1000h. The tensile strength retention rate TR before and after aging was tested, in units of 0.

[0064] (3) UV aging test: Aging is carried out according to the cycle-1 conditions of Method A in ISO4892-3. The color plate is placed in the UV aging chamber for 168 hours and the color difference ΔE before and after aging is tested.

[0065] Table 1. Weight parts and test results of each component in the nylon compositions of Examples 1-10:

[0066]

[0067] As can be seen from Examples 1-13, the nylon composition prepared by the present invention can simultaneously achieve the properties of low mold fouling, resistance to damp heat aging, and UV resistance. Example 10 uses melamine cyanurate as a halogen-free flame retardant. This substance is more easily decomposed than other halogen-free flame retardants, which will cause a slight increase in mold fouling mass.

[0068] Table 2. Weight parts of each component and test results of the nylon compositions in Comparative Examples 1-7:

[0069]

[0070] As can be seen from Comparative Examples 1-4, when sodium lignosulfonate does not simultaneously meet the requirements of sulfonation degree of 1.0-1.2 mmol / g and weight-average molecular weight of 10000-14000 Da, the experimental results show that the prepared nylon composition cannot simultaneously meet the requirements of low scale buildup, resistance to damp heat aging, and UV resistance.

[0071] As shown in Comparative Examples 5-6, when calcium lignosulfonate and magnesium lignosulfonate are used instead of sodium lignosulfonate, the nylon compositions prepared exhibit a significant decrease in both damp heat resistance and UV resistance. It is speculated that this is because calcium lignosulfonate and magnesium lignosulfonate are acidic and cannot neutralize the acidity of the halogen-free flame retardant.

[0072] Comparative Example 7 is a blank control without the addition of sodium lignosulfonate.

Claims

1. A nylon composition, characterized in that, Based on parts by weight, it contains the following components: 24-82.5 parts of PA resin; 10-50 parts glass fiber; Sodium lignosulfonate 0.5-2 parts; 7-23 parts of halogen-free flame retardant; Among them, sodium lignosulfonate has a sulfonation degree of 1.0-1.2 mmol / g and a weight-average molecular weight of 10,000-14,000 Da.

2. The nylon composition according to claim 1, characterized in that, The PA resin is selected from any one or more of nylon 6, nylon 66, or copolymers of nylon 6 and nylon 66.

3. The nylon composition according to claim 1, characterized in that, The glass fiber is selected from short-cut fibers treated with a silane coupling agent containing amino or epoxy functional groups.

4. The nylon composition according to claim 1, characterized in that, The halogen-free flame retardant is selected from phosphorus-nitrogen-based halogen-free flame retardants.

5. The nylon composition according to claim 4, characterized in that, The phosphorus-nitrogen-based halogen-free flame retardant is selected from any one or more of red phosphorus, diethyl aluminum hypophosphite, melamine polyphosphate, or melamine cyanurate.

6. The nylon composition according to claim 1, characterized in that, The product also includes 0.01-2 parts by weight of processing aids, which are selected from any one or more antioxidants or lubricants.

7. The nylon composition according to claim 6, characterized in that, The antioxidant is selected from any one or more of hindered phenols, phosphites, or thiophosphates; the lubricant is selected from any one or more of oxidized polyethylene wax, ethylene bis-fatty acid amide, or pentaerythritol stearate.

8. A method for preparing the nylon composition according to any one of claims 1-7, characterized in that, Includes the following steps: M1: Dry the PA resin, mix the dried PA resin and other components except glass fiber according to the formula, and put the mixture into the main feed hopper of the twin-screw extruder; M2: The glass fiber is fed into the side feed hopper of the twin-screw extruder; M3: Set the temperature of each zone of the twin-screw extruder to 230-280℃, the feed rate to 300-500kg / h, and the main machine speed to 300-400rpm; M4: The melt is extruded through an extruder, cooled, and air-dried to obtain a nylon composition.

9. The use of the nylon composition according to any one of claims 1-7, characterized in that, Used to manufacture electrical management components or power tools.

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