Black low-odor long-term heat-oxygen-resistant long glass fiber reinforced polypropylene material and preparation method thereof

Abstract

The invention belongs to the technical field of functional materials, and particularly relates to a black low-odor long-term heat-oxygen-resistant long glass fiber reinforced polypropylene material and a preparation method thereof. The composite material comprises the following components in parts by weight: 60-70 parts of PP, 3-8 parts of a compatilizer PP-g, 25-35 parts of glass fibers, 0.2-0.6 part of carbon black, 0.3-0.8 part of a lubricant, 0-2 parts of a deodorant and 1-2 parts of a composite antioxidant. Wherein the compatilizer PP-g is PP grafted maleic anhydride, and the composite antioxidant is composed of hindered phenol, phosphite ester and thioester. Through the composite antioxidant, after the material is subjected to a thermo-oxidative aging test at the temperature of 150 DEG C for 1000 hours, the surface of the material is free of differentiation cracking, and the tensile and impact performance retention rate is still 85% or above.

Description

Technical Field

[0001] The invention belongs to the technical field of functional materials, and specifically relates to a black, low-odor, long-term heat-oxidation-resistant long glass fiber reinforced polypropylene material and a preparation method thereof. Background Art

[0002] With the recovery of the global economy and the development of emerging markets, automobile production continues to grow, providing a huge market demand for automotive plastics. The rapid development of new energy vehicles has made the demand for lightweight materials more urgent. New energy vehicles require longer driving range and lower energy consumption, and lightweighting is one of the important means to achieve this goal. Therefore, the popularity of new energy vehicles will drive the rapid growth of the automotive plastics market.

[0003] Lightweighting of automobiles is one of the important directions of the development of the automobile industry. It is of great significance to improve automobile performance, reduce fuel consumption and emissions. Ordinary PP materials are widely used in the manufacture of bumpers, dashboards, door panels, etc. due to their low cost, light weight, easy painting, and recyclability. Long glass fiber reinforced polypropylene (LGFPP) materials perform well in the manufacture of automotive front-end modules such as radiators, speakers, condensers, brackets and other components. This material has higher comprehensive properties, such as high-temperature fatigue strength, corrosion resistance and low density, which can significantly reduce the weight of the car and improve fuel economy. Long glass fiber reinforced polypropylene (LGFPP) is a composite material formed by adding glass fibers with a length of 10 to 25 mm to polypropylene. Due to its three-dimensional cross-distributed long glass fiber structure, long glass fiber reinforced polypropylene has significantly higher tensile strength, impact strength and hardness than ordinary polypropylene. It has excellent dimensional stability and creep resistance. It also has good fatigue resistance and weather resistance, and can maintain stable mechanical properties at extreme temperatures. Compared to metal materials, long glass fiber reinforced polypropylene has higher specific strength and specific stiffness, which makes it an ideal choice for replacing metal, especially in the automotive manufacturing field.

[0004] Although LGFPP has shown excellent performance and application prospects in the automotive field, it also has some disadvantages. First of all, long glass fiber reinforced polypropylene may produce sour and burnt odors during processing, which mainly come from factors such as the base material PP resin, long glass fiber surface treatment agent coupling agent, compatibilizer and injection molding processing temperature. These odors not only affect the sensory quality of the product, but may also have adverse effects on the production environment and personnel health. In addition, since the material itself is very sensitive to heat and oxygen, black is more likely to absorb heat and is prone to oxidative degradation, resulting in reduced mechanical properties. Therefore, the heat and oxygen aging test of the black LGFPP material is also an important assessment item for the performance of the LGFPP material.

[0005] Patent CN202010384201.1 provides a low-odor, low-VOC long glass fiber reinforced polypropylene composite material and a preparation method thereof, comprising the following raw materials by weight: 50-70 parts of PP resin, 30-50 parts of low-odor, low-VOC flat glass fiber coated with a low-odor, low-VOC sizing agent, 0-1 parts of lubricant, 0-4 parts of compatibilizer, 0-2 parts of antioxidant, and 0-2 parts of black masterbatch; the scheme uses low-odor, low-VOC flat glass fiber to replace ordinary cylindrical glass fiber, reduce the odor and VOC content of long glass fiber reinforced polypropylene composite materials, improve the fluidity, mechanical properties and appearance of long glass fiber reinforced polypropylene composite materials, and reduce the warpage deformation of long glass fiber reinforced polypropylene composite products. At the same time, low-odor, high-activity maleic anhydride grafted PP is used as a compatibilizer, making full use of its extremely high capacity expansion efficiency and high reactive groups, and further reducing the odor and VOC content of flat long glass fiber reinforced PP composite materials while ensuring performance. However, the anti-thermal oxidative aging performance needs to be improved. Summary of the invention

[0006] The object of the present invention is to provide a black, low-odor, long-term heat-oxidation-resistant long glass fiber reinforced polypropylene material and a preparation method thereof, and to significantly improve the heat-oxidation-resistant aging performance by using a composite antioxidant.

[0007] To achieve the above object, the present invention provides a black low-odor, long-term heat-resistant and oxygen-resistant long glass fiber reinforced polypropylene material, which comprises, by weight: 50-70 parts of PP, 5-10 parts of compatibilizer PP-g, 20-40 parts of glass fiber, 0.3-0.6 parts of carbon black, 0.3-0.5 parts of lubricant, 0.5-1 parts of deodorant, and 0.5-1.5 parts of composite antioxidant;

[0008] The compatibilizer PP-g refers to PP grafted with maleic anhydride, and the composite antioxidant is composed of hindered phenol, phosphite and thioester.

[0009] Furthermore, the mass ratio of the hindered phenol, the phosphite and the thioester is 4:3:3.

[0010] Furthermore, the hindered phenol is specifically antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate), the phosphite is specifically antioxidant 168 (tris(2,4-di-tert-butylphenyl) phosphite), and the thioester is specifically antioxidant 412S (pentaerythritol tetrakis(3-laurylthiopropionate)).

[0011] Furthermore, the deodorant is a mixture of 40-60 wt % of diethyl aluminum diacrylate and 40-60 wt % of zinc dimethacrylate.

[0012] Furthermore, the glass fiber has a linear density of 2400 tex and a diameter of 17 μm.

[0013] The present invention also provides a method for preparing a black, low-odor, long-term heat-resistant and oxygen-resistant long glass fiber reinforced polypropylene material, comprising: adding PP, a compatibilizer PP-g, a deodorant and carbon black into a batch mixing tank for primary mixing, then adding a composite antioxidant and a lubricant for blending, adding the mixture into a twin-screw extruder after uniform mixing, and then conveying the mixture to a die head, while the glass fiber is drawn into the die head for coating by a fiber release frame, the material strips are cooled to room temperature by a water tank, drawn by a tractor, and granulated by a pelletizer.

[0014] Furthermore, the temperature of each zone of the twin-screw extruder is: first section: 180-220°C; second section: 220-250°C; third section: 230-250°C; die head 220-250°C.

[0015] In general, the above technical solution conceived by the present invention has the following technical advantages compared with the prior art:

[0016] The black low-odor, long-term heat-oxidation-resistant long glass fiber reinforced polypropylene material provided by the present invention not only controls the odor output from the aspects of low-odor raw materials, cleaning equipment, odor post-treatment, etc., but also adds a powder deodorant to remove the odor small molecules generated during the production process. In addition, by adding an antioxidant compounded by hindered phenol, phosphite and thioester, its heat-oxidation aging resistance is improved. After a 150°C, 1000h heat-oxidation aging test, there is no differentiation and cracking on the surface, and the tensile and impact performance retention rate is still above 85%. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention provides a flow chart of the preparation method of the black, low-odor, long-term heat and oxygen-resistant long glass fiber reinforced polypropylene material. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0019] Example

[0020] A black low-odor, long-term heat and oxygen resistant long glass fiber reinforced polypropylene material comprises, by weight: low-VOC polypropylene (PP): 50-70 parts; low-VOC compatibilizer (PP-g): 5-10 parts; low-VOC glass fiber: 20-40 parts; composite antioxidant: 0.5-1.5 parts; lubricant: 0.3-0.5 parts; carbon black: 0.3-0.6 parts; deodorant: 0.5-1 parts.

[0021] Among them, the compatibilizer PP-g refers to PP grafted maleic anhydride, the composite antioxidant is composed of hindered phenol (specifically antioxidant 1010), phosphite (specifically antioxidant 168) and thioester (specifically antioxidant 412S) in a mass ratio of 4:3:3, and the deodorant is a mixture of 50wt% diethyl diacrylate aluminum salt and 50wt% zinc dimethacrylate.

[0022] The specific formula is shown in Table 1. In Table 1, the common antioxidant refers to antioxidant 1010.

[0023] The low-odor raw material PP, compatibilizer PP-g, deodorant and carbon black are added to the batch mixing tank for initial mixing. After 10 minutes of batch mixing, antioxidants and lubricants are added for blending. After 20 minutes of mixing until the mixture is uniform, it is added to the twin-screw extruder and then transported to the die head. The temperature of each zone of the extruder is: first stage: 180-220℃; second stage: 220-250℃; third stage: 230-250℃; die head 220-250℃. After that, the glass fiber is pulled into the die head for coating by the fiber release frame, and the material strips are cooled to room temperature through the water tank, pulled by the traction machine, and granulated by a special pelletizer.

[0024] For the odor level test, refer to "Odor Properties of Automotive Interior Materials". Specifically, select 20g of finished particles and place them in a 1L odor test bottle; place them in an oven at 80°C for 2h, take them out and wait for the bottle to cool to 60°C before evaluating the odor.

[0025] Judging criteria:

[0026] Level 1, not easily felt;

[0027] Level 2: can be felt but not pungent;

[0028] Level 3: can be clearly felt, but not pungent;

[0029] Level 4, pungent;

[0030] Level 5, very pungent;

[0031] Level 6, unbearable.

[0032] Table 1 Formulation and performance of Examples 1-4

[0033]

[0034] It can be seen from Table 1 that the odor level is reduced after adding the deodorant in Examples 2 and 4. In terms of heat and oxygen aging resistance, compared with ordinary antioxidants, the composite antioxidant of the present invention plays a greater role in LGFPP. Not only does the appearance not change significantly after testing at 150°C for 1000h, but the performance retention rate is also around 90%.

[0035] In summary, the present invention adds a PP deodorant to reduce odor better and more effectively. In terms of long-term heat and oxygen resistance, hindered phenolic main antioxidants are selected, and long-acting and short-acting auxiliary antioxidants such as phosphites and thioesters are used in combination. After adding this composite antioxidant, LGFPP has no differentiation and cracking on the surface after 150°C, 1000h heat and oxygen aging test, and the tensile and impact performance retention rate is still above 85%. This black low-odor, long-term heat and oxygen resistant long glass fiber reinforced polypropylene material composite material has high performance, low odor, and good heat and oxygen resistance, and is widely used in automotive parts.

[0036] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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 present invention.

Claims

1. A black, low-odor, long-term heat-resistant and oxygen-resistant long glass fiber reinforced polypropylene material, characterized in that: The composition includes 50-70 parts of PP, 5-10 parts of compatibilizer PP-g, 20-40 parts of glass fiber, 0.3-0.6 parts of carbon black, 0.3-0.5 parts of lubricant, 0.5-1 parts of deodorant, and 0.5-1.5 parts of composite antioxidant by weight. The compatibilizer PP-g refers to PP grafted with maleic anhydride, and the composite antioxidant is composed of hindered phenol, phosphite and thioester.

2. The black low-odor, long-term heat-resistant and oxygen-resistant long glass fiber reinforced polypropylene material according to claim 1, characterized in that: The mass ratio of the hindered phenol, the phosphite and the thioester is 4:3:

3.

3. The black low-odor, long-term heat-resistant and oxygen-resistant long glass fiber reinforced polypropylene material according to claim 2, characterized in that: The hindered phenol is specifically antioxidant 1010, the phosphite is specifically antioxidant 168, and the thioester is specifically antioxidant 412S.

4. The black low-odor, long-term heat-resistant and oxygen-resistant long glass fiber reinforced polypropylene material according to claim 1, characterized in that: The deodorant is prepared by mixing 40-60 wt % of diethyl diacrylate aluminum salt and 40-60 wt % of dimethacrylate zinc.

5. The black low-odor, long-term heat-resistant and oxygen-resistant long glass fiber reinforced polypropylene material according to claim 1, characterized in that: The glass fiber has a linear density of 2400 tex and a diameter of 17 μm.

6. A method for preparing a black, low-odor, long-term heat-resistant and oxygen-resistant long glass fiber reinforced polypropylene material, characterized in that: include: PP, compatibilizer PP-g, deodorant and carbon black are added to the batch mixing tank for initial mixing, and then the composite antioxidant and lubricant are added for blending. After mixing evenly, they are added to the twin-screw extruder and then conveyed to the die head. At the same time, the glass fiber is pulled into the die head for coating through the fiber release frame. The material strips are cooled to room temperature through a water trough, pulled by a traction machine, and granulated by a pelletizer.

7. The preparation method according to claim 6, characterized in that: The temperature of each zone of the twin-screw extruder is: Stage 1: 180-220°C; Second stage: 220-250℃; third stage: 230~250℃; die head 220~250℃.

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