High-modulus and high-toughness flame-retardant polypropylene material prepared from waste meal box reclaimed material and preparation method of high-modulus and high-toughness flame-retardant polypropylene material

Abstract

The invention discloses a high-modulus and high-toughness flame-retardant polypropylene material prepared from a waste meal box reclaimed material and a preparation method of the high-modulus and high-toughness flame-retardant polypropylene material. The polypropylene compound comprises the following components in percentage by weight: 50-70% of polypropylene waste meal box reclaimed material; 30-40% of glass short fiber and 3-4% of maleic anhydride grafted polypropylene; 2-3% of a compound low-halogen flame retardant; 0.35%-0.75% of a flame-retardant synergistic synergist and 0.2%-0.8% of an antioxidant. The material has mechanical properties similar to those of a high-modulus and high-toughness polypropylene material produced from brand new materials, and the flame retardant property can reach V2 level. According to the invention, wastes are recycled, so that environmental pollution is reduced, resource recycling is realized, and great economic benefits and social benefits are achieved.

Description

Technical Field

[0001] The invention relates to the field of polypropylene composite materials, and in particular to a high-modulus, high-toughness flame-retardant polypropylene material prepared from recycled waste lunch box materials and a preparation method thereof. Background Art

[0002] Polypropylene has always been the focus of the automotive industry and the plastics industry because of its advantages such as low density, high strength, high hardness, wear resistance, bending fatigue resistance, high heat resistance, excellent moisture and chemical resistance, easy processing and molding, and low price. However, polypropylene itself is a flammable material, and its limiting oxygen index is only 17.4%~18.5%, and its carbonization rate is low. When it burns, it produces molten droplets, which can easily spread flames and cause fires, making it unsafe and greatly limiting its application range. Improving the flame retardant properties of polypropylene by adding flame retardants is an effective way to expand its application range.

[0003] In recent years, people's awareness of fire safety and environmental protection has been continuously enhanced. While requiring materials to have good flame retardant properties, they are also required to have the basic requirements of no (low) halogen, non-toxicity and low smoke. Phosphorus-nitrogen-bromine compound flame retardant system has been widely used in polypropylene products. Under the premise of only 0.8~2% addition, it gives polypropylene materials V2 flame retardant properties while meeting the environmental protection requirements of today's social development. In addition, the flame retardant has little effect on the mechanical properties of the flame retardant material matrix, making the material have excellent comprehensive properties. However, the phosphorus-nitrogen-bromine compound flame retardant system belongs to a dripping flame retardant system. In the high glass fiber filled polypropylene system, due to the large amount of glass fiber, the polypropylene material is not easy to drip when burning, which will eventually lead to the failure of the phosphorus-nitrogen-bromine compound flame retardant. In addition, due to the production of polypropylene glass fiber materials, the glass fiber will also release a lot of shear heat when it is sheared, resulting in the failure of the phosphorus-nitrogen-bromine compound flame retardant. Summary of the invention

[0004] The invention discloses a high modulus and high toughness flame-retardant polypropylene material prepared by using recycled materials of waste lunch boxes, which can replace V2 grade glass fiber reinforced polypropylene material produced by new materials and can be used in various bracket products.

[0005] A high modulus, high toughness flame-retardant polypropylene material prepared from recycled waste lunch boxes, characterized in that it comprises the following components in percentage by weight: 50%~70% recycled materials from waste lunch boxes; Maleic anhydride grafted polypropylene 3%~4% Glass staple fiber 30%-40% Compound low-halogen flame retardant 2%~3%; Flame retardant synergist 0.35%~0.75%; Antioxidant 0.2%~0.8%; The recycled waste lunch box material is made from recycled waste lunch boxes, which are used after being cleaned and crushed. The recycled waste lunch box material is characterized in that the melting point range is 40-50 g / 10min and the density is 0.90-0.91 g / cm3. The maleic anhydride grafting rate of the maleic anhydride grafted polypropylene is 0.4-0.9%. The glass staple fiber is an alkali-free staple fiber.

[0006] The compound low-halogen flame retardant is a phosphorus-nitrogen-bromine compound flame retardant, including melamine hydrobromide salt, ammonium polyphosphate and 2,3-dimethyl-2,3-diphenylbutane. The flame retardant synergist is p-isopropylbenzene polymer or DC RM4-7801 silicone flame retardant from DOW corning. The compound low-halogen flame retardant: p-isopropylbenzene polymer flame retardant synergist is 6:1~4:1. Too high or too low has an adverse effect on flame retardancy, and compared with the silicone flame retardant synergist, it has higher impact strength.

[0007] The antioxidant comprises a primary antioxidant and a secondary antioxidant, wherein the primary antioxidant is one or a combination of hindered phenol or thioester antioxidants, and the secondary antioxidant is one or a combination of phosphite or ester antioxidants.

[0008] The present invention also discloses a method for preparing a high modulus, high toughness flame-retardant polypropylene material prepared from recycled materials of waste lunch boxes. Recycled materials of waste lunch boxes, maleic anhydride grafted polypropylene, compounded low-halogen flame retardant, flame retardant synergist, antioxidant are mixed to obtain a mixture, and then the mixture is added from the main feed port to a twin-screw extruder for melt blending. The twin-screw extruder includes 11 heating working zones connected in sequence, and the glass fiber is added from the 8th heating working zone of the twin-screw extruder. After extrusion and granulation by the twin-screw extruder, a material having mechanical properties and flame retardant properties similar to those of waste lunch box materials produced from new materials is obtained. The temperature of the 11 heating working zones of the twin-screw extruder from the feed port to the extrusion granulation is: 60℃~70℃, 185℃~195℃, 185℃~195℃, 185℃~195℃, 180℃~190℃, 180℃~190℃, 180℃~190℃, 190℃~200℃, 190℃~200℃, 180℃~190℃, 180℃~190℃. The aspect ratio of the twin-screw extruder is 50~55:1. The first 7 heating working zones of the extruder adopt a weak shear screw combination, and the 8th heating zone and the 9th heating zone adopt a strong shear screw combination. The 10th to 11th zones adopt a weak screw combination. The solid conveying section of the 1st-2nd zone adopts multiple groups of positive rotation conveying elements, and the melt mixing section of the 3rd-7th zone adopts no more than 4 groups of 45° and 60° positive rotation kneading elements. The 8th and 9th zones use two or more 90° neutral kneading elements and one reverse-rotation kneading element. The venting and devolatilization section of the 10th and 11th zones uses forward-rotation conveying elements instead of kneading elements. The modified resin is finally transported, melted, blended, vented, and extruded by the extruder.

[0009] Compared with the prior art, the present invention has the following advantages: This patent uses waste lunch boxes as raw materials, realizing resource recycling, which has great economic and social benefits. This patent adopts a special production process and screw combination to give the composite material high modulus and V2 grade flame retardant performance under the premise of low addition of flame retardant. It can be used in large quantities as a supporting material in various industries, with extremely high cost performance.

[0010] The present invention uses recycled materials from waste lunch boxes, and adds 30-40% of glass fiber to the recycled materials through a special screw combination and processing technology. The length of the glass fiber is retained as high as possible, giving the composite material a high modulus characteristic, and the maximum modulus can reach 7000Mpa. In addition, due to the existence of the special screw combination and process, the generation of shear heat in the production process is reduced, so that the flame retardant effect of the low-halogen flame retardant is retained to the maximum extent. Finally, with the use of a flame retardant synergist, the dripping of the material is accelerated when the composite material burns, so that the material of this patent invention reaches the V2 flame retardant level under the condition of a low amount of added flame retardant, which has significant social and economic benefits.

[0011] The invention discloses a method for preparing a high modulus flame-retardant polypropylene material by utilizing recycled materials of waste lunch boxes, which has simple equipment, is easy to implement and operate, is easy to industrialize and has broad application prospects. Implementation

[0012] The recycled materials from used lunch boxes are homemade products; the compound low-halogen flame retardant is FR1218 produced by Guangzhou Qingyan Company; the glass fiber is 508A produced by Jushi; the maleic anhydride grafted polypropylene is 9801; the antioxidant 1010 is a product produced by BASF of Germany; the antioxidant 168 is also a product produced by BASF of Germany. Example 1

[0013] 64 parts by weight of recycled waste lunch box material, 2 parts by weight of compound low-halogen flame retardant, 0.5 parts of flame retardant synergist (isopropylbenzene polymer), 3 parts by weight of 9801, 0.25 parts by weight of antioxidant 1010, and 0.25 parts by weight of antioxidant 168 were added to a high-speed mixer with a rotation speed of about 1000 rpm and mixed for 5 minutes, and then the mixture was added to a twin-screw extruder at the main feed port. 30 parts by weight of glass fiber was added from the 8th zone. Extrusion granulation was obtained to obtain a polypropylene composite material. Example 2

[0014] 63.9 parts by weight of recycled materials from waste lunch boxes, 2 parts by weight of compound low-halogen flame retardant, 0.6 parts of flame retardant synergist (isopropylbenzene polymer), 3 parts by weight of 9801, 0.25 parts by weight of antioxidant 1010, and 0.25 parts by weight of antioxidant 168 were added to a high-speed mixer with a rotation speed of about 1000 rpm and mixed for 5 minutes, and then the mixture was added to a twin-screw extruder at the main feed port. 30 parts by weight of glass fiber was added from the 8th zone. Extrusion granulation was performed to obtain a polypropylene composite material. Example 3

[0015] 64 parts by weight of recycled materials from waste lunch boxes, 2 parts by weight of compound low-halogen flame retardant, 0.5 parts of flame retardant synergist (DCRM4-7801 silicone flame retardant), 3 parts by weight of 9801, 0.25 parts by weight of antioxidant 1010, and 0.25 parts by weight of antioxidant 168 were added to a high-speed mixer with a rotation speed of about 1000 rpm and mixed for 5 minutes, and then the mixture was added to a twin-screw extruder at the main feed port. 30 parts by weight of glass fiber was added from the 8th zone. Extrusion granulation was performed to obtain a polypropylene composite material. Example 4

[0016] 52 parts by weight of recycled materials from waste lunch boxes, 3 parts by weight of compound low-halogen flame retardant, 0.5 parts of flame retardant synergist (isopropylbenzene polymer), 4 parts by weight of 9801, 0.25 parts by weight of antioxidant 1010, and 0.25 parts by weight of antioxidant 168 were added to a high-speed mixer with a rotation speed of about 1000 rpm and mixed for 5 minutes, and then the mixture was added to a twin-screw extruder at the main feed port. 40 parts by weight of glass fiber was added from the 8th zone. Extrusion granulation was obtained to obtain a polypropylene composite material. Example 5

[0017] 52.1 parts by weight of recycled materials from waste lunch boxes, 3 parts by weight of compound low-halogen flame retardant, 0.4 parts of flame retardant synergist (isopropylbenzene polymer), 4 parts by weight of 9801, 0.25 parts by weight of antioxidant 1010, and 0.25 parts by weight of antioxidant 168 were added to a high-speed mixer with a rotation speed of about 1000 rpm and mixed for 5 minutes, and then the mixture was added to a twin-screw extruder at the main feed port. 40 parts by weight of glass fiber was added from the 8th zone. Extrusion granulation was performed to obtain a polypropylene composite material. Example 6

[0018] 52 parts by weight of recycled materials from waste lunch boxes, 3 parts by weight of compound low-halogen flame retardant, 0.5 parts of flame retardant synergist (DCRM4-7801 silicone flame retardant), 4 parts by weight of 9801, 0.25 parts by weight of antioxidant 1010, and 0.25 parts by weight of antioxidant 168 were added to a high-speed mixer with a rotation speed of about 1000 rpm and mixed for 5 minutes, and then the mixture was added to a twin-screw extruder at the main feed port. 40 parts by weight of glass fiber was added from the 8th zone. Extrusion granulation was obtained to obtain a polypropylene composite material.

[0019] Comparative Example 1: 65 parts by weight of MM60, 2 parts by weight of compound low-halogen flame retardant, 0.5 parts of flame retardant synergist (isopropylbenzene polymer), 3 parts by weight of 9801, 0.25 parts by weight of antioxidant 1010, and 0.25 parts by weight of antioxidant 168 were added to a high-speed mixer with a rotation speed of about 1000 rpm and mixed for 5 minutes, and then the mixture was added to a twin-screw extruder at the main feeding port. 30 parts by weight of glass fiber was added from the 8th zone. Extrusion granulation was obtained to obtain a polypropylene composite material.

[0020] Comparative Example 2: 52 parts by weight of MM60, 3 parts by weight of compound low-halogen flame retardant, 0.5 parts of flame retardant synergist (isopropylbenzene polymer), 4 parts by weight of 9801, 0.25 parts by weight of antioxidant 1010, and 0.25 parts by weight of antioxidant 168 were added to a high-speed mixer with a rotation speed of about 1000 rpm and mixed for 5 minutes, and then the mixture was added to a twin-screw extruder at the main feeding port. 40 parts by weight of glass fiber was added from the 8th zone. Extrusion granulation was obtained to obtain a polypropylene composite material.

[0021] Comparative Example 3: 63.5 parts by weight of recycled materials from waste lunch boxes, 3 parts by weight of compound low-halogen flame retardant, 3 parts by weight of 9801, 0.25 parts by weight of antioxidant 1010, and 0.25 parts by weight of antioxidant 168 were added to a high-speed mixer with a rotation speed of about 1000 rpm and mixed for 5 minutes, and then the mixture was added to a twin-screw extruder at the main feeding port. 30 parts by weight of glass fiber was added from the 8th zone. Extrusion granulation was performed to obtain a polypropylene composite material.

[0022] Comparative Example 4: 61.5 parts by weight of recycled materials from waste lunch boxes, 5 parts by weight of compound low-halogen flame retardant, 3 parts by weight of 9801, 0.25 parts by weight of antioxidant 1010, and 0.25 parts by weight of antioxidant 168 were added to a high-speed mixer with a rotation speed of about 1000 rpm and mixed for 5 minutes, and then the mixture was added to a twin-screw extruder at the main feeding port. 30 parts by weight of glass fiber was added from the 8th zone. Extrusion granulation was performed to obtain a polypropylene composite material.

[0023] Comparative Example 5: 64 parts by weight of recycled materials from waste lunch boxes, 2 parts by weight of compound low-halogen flame retardant, 0.5 parts of flame retardant synergist (isopropylbenzene polymer), 3 parts by weight of 9801, 0.25 parts by weight of antioxidant 1010, and 0.25 parts by weight of antioxidant 168 were added to a high-speed mixer with a rotation speed of about 1000 rpm and mixed for 5 minutes, and then the mixture was added to a twin-screw extruder at the main feed port. 30 parts by weight of glass fiber was added from the 5th zone. Extrusion granulation was performed to obtain a polypropylene composite material.

[0024] Table 1 Mechanical and flame retardant properties of the examples and comparative examples

[0025] By analyzing the above examples and comparative data, it is not difficult to find that the mechanical properties and flame retardant properties of the composite materials of Examples 1 and 4 produced using the formula and processing method of the present invention are very close to those of the composite materials of Comparative Examples 1 and 2 produced using new materials. Compared with Example 1, Comparative Examples 3 and 4 do not add flame retardant synergists, resulting in the final composite materials not being able to produce effective dripping when burning. Since the addition amount of the compounded low-halogen flame retardant is increased to 5%, the flame retardant properties of the composite materials still cannot reach the V2 level. It is proved that the flame retardant synergist can form an effective synergistic effect with the low-halogen flame retardant in the invention, so that the high glass fiber filled polypropylene can reach the V2 level of flame retardant when the material is added with a low amount of flame retardant. Compared with Example 2 and Example 1, and Example 5 and Example 4, the ratio of flame retardant to flame retardant synergist is too high or too low, and the flame retardant V2 level cannot be reached. Compared with Examples 1~2, and Example 6 and Examples 4~5, p-isopropylbenzene polymer is used as a flame retardant synergist, and the material has higher impact strength. In comparative example 5, glass fiber is added in zone 5. From the test results, it can be seen that in comparative example 5 and example 1, under the same formula, the glass fiber retention length is greatly reduced due to the early addition of glass fiber material, and the mechanical properties of the final composite material are seriously reduced. In addition, the shear heat when the glass fiber is sheared affects the effect of the flame retardant, resulting in the flame retardant performance not reaching the V2 flame retardant level. Therefore, the formula and processing method of the invention of this patent can prepare a high modulus, high toughness flame retardant polypropylene material made from recycled waste lunch boxes with performance close to that of new materials.

Claims

1. A high modulus, high toughness flame retardant polypropylene material prepared from recycled waste lunch boxes, characterized in that: Contains the following components in weight percentage: 50%~70% recycled materials from waste lunch boxes; Maleic anhydride grafted polypropylene 3%~4% Glass staple fiber 30%-40% Compound low-halogen flame retardant 2%~3%; Flame retardant synergist 0.35%~0.75%; Antioxidant 0.2%~0.8%.

2. The high modulus, high toughness flame retardant polypropylene material prepared from recycled waste lunch boxes according to claim 1, characterized in that: The recycled waste lunch box material has a melting point range of 40-50 g / 10min and a density of 0.90-0.91 g / cm 3 .

3. The high modulus, high toughness flame retardant polypropylene material prepared from recycled waste lunch boxes according to claim 1, characterized in that: The maleic anhydride grafted polypropylene has a maleic anhydride grafting rate of 0.4-0.9%.

4. The high modulus, high toughness flame retardant polypropylene material prepared from recycled waste lunch boxes according to claim 1, characterized in that: The glass staple fibers are alkali-free staple fibers.

5. The high modulus, high toughness flame retardant polypropylene material prepared from recycled waste lunch boxes according to claim 1, characterized in that: The compound low-halogen flame retardant is a phosphorus-nitrogen-bromine compound flame retardant.

6. The high modulus, high toughness flame retardant polypropylene material prepared from recycled waste lunch boxes according to claim 1, characterized in that: The flame retardant synergist is p-isopropylbenzene polymer or organosilicon flame retardant.

7. The high modulus, high toughness flame retardant polypropylene material prepared from recycled waste lunch boxes according to claim 1, characterized in that: The antioxidant includes a primary antioxidant and a secondary antioxidant. The primary antioxidant is one or a combination of hindered phenol or thioester antioxidants, and the secondary antioxidant is one or a combination of phosphite or ester antioxidants.

8. A method for preparing a high modulus, high toughness flame-retardant polypropylene material using recycled materials from waste lunch boxes according to any one of claims 1 to 7, the method comprising the following steps: A mixture is obtained by mixing recycled materials from waste lunch boxes, maleic anhydride grafted polypropylene, a compound low-halogen flame retardant, a flame retardant synergist and an antioxidant, and then the mixture is added from a main feeding port to a twin-screw extruder for melt blending. The twin-screw extruder includes 11 heating working zones connected in sequence. Glass fiber is added from the 8th heating working zone of the twin-screw extruder, and the mixture is extruded and granulated through the twin-screw extruder to obtain a high modulus flame retardant polypropylene material prepared from recycled materials from waste lunch boxes.

9. The method for preparing a high modulus, high toughness flame-retardant polypropylene material using recycled materials from waste lunch boxes according to claim 8, characterized in that: The temperatures of the 11 heating working zones of the twin-screw extruder from the feeding port to the extrusion granulation are: 60°C~70°C, 185°C~195°C, 185°C~195°C, 185°C~195°C, 180°C~190°C, 180°C~190°C, 180°C~190°C, 190°C~200°C, 190°C~200°C, 180°C~190°C, 180°C~190°C.

10. The high modulus flame retardant polypropylene material prepared from recycled waste lunch boxes according to claim 1, characterized in that: The length-to-diameter ratio of the twin-screw extruder is 48-52:1.

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