Patent Publication Number: US-2023159712-A1

Title: Reinforced polypropylene material and preparation method thereof

Description:
TECHNICAL FIELD 
     The present invention relates to the technical field of engineering plastics, and specifically to a reinforced polypropylene material and a preparation method thereof. 
     RELATED ART 
     As a polymer material with the largest consumption at present, polypropylene materials have advantages such as excellent processing properties and mechanical properties, which are widely used in daily life and industrial production fields, such as agricultural film, wire and cable, communication, housing construction and aviation manufacturing. 
     Glass fibers are generally used as a reinforcing medium in conventional reinforced polypropylene materials, and high strength and high rigidity of the glass fibers make the product have improved strength and heat resistance. However, conventional glass fiber-reinforced polypropylene materials have defects of poor light-aging resistance and thermal-aging resistance, and poor low-temperature tenacity, which cannot be used in long-term severe environment. 
     It is surprisingly found through a lot of experiments by the inventors that by adjusting the length and content distribution of reinforcing fibers in the formulas of reinforced polypropylene material, greatly retaining the length of reinforcing fibers in the reinforced polypropylene material, and by combining a specific amount of low-hardness colorant powder and supplementing with a specific amount of compatilizer, the obtained reinforced polypropylene material would have obviously improved low-temperature tenacity and long-term weathering resistance without adding a toughening agent or a conventional weather-resistant agent, so as to meet the requirement of long-term application of materials. 
     SUMMARY OF INVENTION 
     In order to overcome the defects and deficiencies of the prior art, the objective of the present invention is to provide a reinforced polypropylene material with significantly improved low-temperature tenacity and long-term weathering resistance. 
     Another objective of the present invention is to provide a preparation method for the above-mentioned reinforced polypropylene material. 
     The present invention is realized by the following technical solutions. 
     A reinforced polypropylene material includes the following components in parts by weight:
         a, 10 to 90 parts of a polypropylene resin;   b, 0.5 to 25 parts of a compatilizer;   c, 5 to 60 parts of reinforcing fibers;   d, 0.1 to 20 parts of low-hardness colorant powder;   the reinforcing fibers include a component I, a component II and a component III:   the component I is composed of reinforcing fibers with a length of 0.1 mm to 0.6 mm, accounting for 35% to 50% of a number of reinforcing fibers;   the component II is composed of reinforcing fibers with a length of 0.7 mm to 1.3 mm, accounting for 35% to 45% of the number of reinforcing fibers;   the component III is composed of reinforcing fibers with a length of 1.4 mm to 2.0 mm, accounting for 5% to 20% of the number of reinforcing fibers.       

     The reinforcement effect of the reinforcing fibers is related to the dispersion condition, distribution uniformity and orientation of the reinforcing fibers in the matrix resin, and to the interface condition of the matrix resin. Generally, the greater the length of the glass fibers is retained, the better the mechanical performance and heat resistance are achieved. When the length of the reinforcing fibers and the retained length of the glass fibers are too short, rigidity and heat resistance of the material would be greatly weakened. When the length of the reinforcing fibers is too long, the plastic particles become too long, which would affect the feeding during the processing. 
     Specifically, the component I in the reinforcing fibers accounts for 38% to 45% of the number of reinforcing fibers. 
     Specifically, the component II in the reinforcing fibers accounts for 37% to 42% of the number of reinforcing fibers. 
     Specifically, the component III in the reinforcing fibers accounts for 8% to 15% of the number of reinforcing fibers. 
     Specifically, the reinforcing fibers are selected from one or more of glass fibers, quartz fibers, and basalt fibers; the reinforcing fibers have a diameter of 5 to 20 microns. 
     Specifically, the low-hardness colorant powder has a Moh&#39;s hardness less than 6; and preferably a Moh&#39;s hardness of 0.1-4. 
     Specifically, the low-hardness colorant powder is selected from one or more of zinc white, zinc sulfide, barium white, antimony white, lithopone, lead white, calcium carbonate, talc powder, kaolin, barium sulfate, and titanium dioxide. 
     Specifically, the polypropylene resin is selected from one or more of homo-polypropylene (PP-H), block copolymerized polypropylene (PP-B) and random copolymerized polypropylene (PP-R). 
     Specifically, the compatilizer is a graft polymer of polar monomer and polypropylene, wherein the polar monomer is selected from one or a mixture of derivatives of maleic anhydrides, acrylic acids and acrylates. 
     The present invention further provides a preparation method for the above-mentioned reinforced polypropylene material which includes the following steps. 
     Each component is weighed according to the formula contents, and all components except for the reinforcing fibers are mixed uniformly. Subsequently, the mixture is added to a primary feeding system of a double-screw extruder; meanwhile the reinforcing fibers are added to a side feeding system of the double-screw extruder, and then the reinforced polypropylene material is obtained after melt-blending, extruding and pelleting by the double-screw extruder. 
     Specifically, feeding position of the side feeding system of the double-screw extruder can be adjusted, wherein the reinforcing fibers can be added to the screw at the first section to the tenth section, and added after the die head of the extruder, followed by directly combining with a polypropylene melt. 
     Specifically, temperature of the first section to the second section of the double-screw extruder ranges from 120° C. to 160° C., temperature of the third section to the fifth section ranges from 180° C. to 300° C., temperature of the fifth section to the tenth section ranges from 180° C. to 300° C. A screw speed is 300 rpm to 600 rpm. 
     Compared with the prior art, the present invention has the following beneficial effects. 
     By adjusting the length and content distribution of the reinforcing fibers in the formulas of reinforced polypropylene material, greatly retaining the length of reinforcing fibers in the reinforced polypropylene material, and by combining a specific amount of low-hardness colorant powder and supplementing with a specific amount of compatilizer, the obtained reinforced polypropylene material would have obviously improved low-temperature tenacity and long-term weathering resistance without adding a toughening agent or a conventional weather-resistant agent, so as to meet the requirement of long-term application of materials. 
    
    
     DESCRIPTION OF EMBODIMENTS 
     The present invention would be further illustrated by the specific implementations, and the following embodiments are preferred implementations of the present invention of which the implementation does not limited thereto. 
     Test Standards or Methods 
     Test methods for length and distribution of reinforcing fibers: a sample strip of notch-impact strength after injection molding was first subjected to high-temperature burning to isolate the reinforcing fibers from a matrix, then length of the reinforcing fibers was measured by using an automatic imaging analysis, and a number of the fibers to be measured was around 2000. 
     Low-temperature tenacity is: notch impact strengths at normal temperature and at −40° C. were measured at the same time; test standard: ISO 180/1A. 
     Long-term weathering resistance is: ISO 4892-2, color difference was measured after aging under a xenon lamp for 100 hours. 
     Polypropylene resin is used in the present invention:
         polypropylene resin: block copolymerized polypropylene (PP-B): PP SP179 from Lanzhou Petrochemical Company.       

     Compatilizer is used in the present invention:
         maleic anhydride grafted polypropylene (PP-g-MAH): 1001CN from Polyram.       

     Reinforcing fibers are used in the present invention:
         glass fibers: diameter of 10 microns, ER4305PM-2400 from Jushi;   quartz fibers: diameter of 5 microns, quartz fiber untwisted yarn SJ114 from Henan Shenjiu Aerospace New Material Inc.;   basalt fibers: diameter of 15 microns, basalt fiber untwisted yarn from Zhejiang GBF Co., Ltd..       

     Low-hardness colorant powder are used in the present invention:
         zinc white: Moh&#39;s hardness of 3.0, from Cangzhou Jieweixinye Co., Ltd.;   antimony white: Moh&#39;s hardness of 3.5, from Changde Chenzhou Antimony Article Co., Ltd.;   titanium dioxide-1: Moh&#39;s hardness of 5.0, BX-200 from Hebei Langfang Qicai       

     Titanium White Powder Manufacturing Co., Ltd.;
         titanium dioxide-2: Moh&#39;s hardness of 7.5, BX-237 from Hebei Langfang Qicai Titanium White Powder Manufacturing Co., Ltd..       

     Toughening agent: POE DF610 is from Singapore Mitsui Chemicals Co., Ltd.. 
     Weather-resistant agent: UV-531 is from Hubei MFCI Co., Ltd.. 
     Examples 1-8 and Comparative Examples 1-6: Preparation for Reinforced Polypropylene Materials 
     Each component was weighed according to the formula contents, and all components except for the reinforcing fibers were mixed uniformly. Subsequently, the mixture was added to a primary feeding system of a double-screw extruder; meanwhile the reinforcing fibers were added to a side feeding system of the double-screw extruder, and then the reinforced polypropylene material was obtained after melt-blending, extruding and pelleting by the double-screw extruder. 
     Specifically, feeding position of the side feeding system of the extruder could be adjusted, wherein the reinforcing fibers could be added to the screw at the first section to the tenth section, and added after the die head of the extruder, followed by directly combining with a polypropylene melt. 
     Specifically, temperature of the first section to the second section of the extruder ranges from 120° C. to 160° C., temperature of the third section to the fifth section ranges from 180° C. to 300° C., temperature of the fifth section to the tenth section ranges from 180° C. to 300° C., and a screw speed is 300 rpm to 600 rpm. 
     Table 1 is specific proportion (parts by weight) of each component in each example and comparative example and performance test results thereof. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
             
               
                   
               
             
            
               
                   
                   
                 Example 1 
                 Example 2 
                 Example 3 
                 Example 4 
                 Example 5 
                 Example 6 
                 Example 7 
                 Example 8 
               
               
                   
               
               
                 Polypropylene 
                 PP SP179 
                 60 
                 60 
                 60 
                 60 
                 10 
                 10 
                 60 
                 60 
               
               
                 resin 
               
               
                 Compatilizer 
                 PP-g-MAH 
                 3 
                 3 
                 3 
                 3 
                 25 
                 25 
                 3 
                 3 
               
               
                 Reinforcing 
                 Glass fibers 
                 30 
                 30 
                 30 
                 30 
                   
                   
                 30 
                 30 
               
               
                 fibers 
                 Quartz fibers 
                   
                   
                   
                   
                 20 
               
               
                   
                 Basalt fibers 
                   
                   
                   
                   
                   
                 40 
               
               
                 Toughening 
                 POE 
               
               
                 agent 
               
               
                 Weather- 
                 UV-531 
               
               
                 resistant 
               
               
                 agent 
               
               
                 Low- 
                 Zinc white 
                 0.2 
               
               
                 hardness 
                 Antimony 
                   
                   
                   
                 0.2 
                 20 
                 5 
                 0.2 
                 0.2 
               
               
                 colorant 
                 white 
               
               
                 powder 
                 Titanium 
                   
                 0.2 
               
               
                   
                 dioxide-1 
               
               
                   
                 Titanium 
                   
                   
                 0.2 
               
               
                   
                 dioxide-2 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 Dosage of the reinforcing 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 fibers added to the first 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
               
               
                 fibers added to the second 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                   
                   
                   
                   
                   
                   
                   
                 5 
               
               
                 fibers added to the third 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                   
                   
                   
                   
                   
                   
                 15 
               
               
                 fibers added to the fourth 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                 5 
                 5 
                 5 
                 5 
                 5 
                 5 
               
               
                 fibers added to the fifth 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
               
               
                 fibers added to the sixth 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                   
                   
                   
                   
                   
                   
                 10 
               
               
                 fibers added to the seventh 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                 5 
                 5 
                 5 
                 5 
                 5 
                 15 
               
               
                 fibers added to the eighth 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
               
               
                 fibers added to the ninth 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
               
               
                 fibers added to the tenth 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                 20 
                 20 
                 20 
                 20 
                 10 
                 20 
                 5 
                 25 
               
               
                 fibers added to the die 
               
               
                 head (part) 
               
               
                 Percentage of Component I 
                 45 
                 38 
                 38 
                 43 
                 40 
                 39 
                 50 
                 35 
               
               
                 accounting for the number 
               
               
                 of reinforcing fibers (%) 
               
               
                 Percentage of Component II 
                 40 
                 42 
                 40 
                 42 
                 38 
                 40 
                 35 
                 45 
               
               
                 accounting for the number 
               
               
                 of reinforcing fibers (%) 
               
               
                 Percentage of Component III 
                 15 
                 13 
                 8 
                 15 
                 12 
                 14 
                 5 
                 20 
               
               
                 accounting for the number 
               
               
                 of reinforcing fibers (%) 
               
               
                 Notch impact strength at 
                 44 
                 28 
                 29 
                 47 
                 40 
                 39 
                 34 
                 33 
               
               
                 normal temperature (KJ/M 2 ) 
               
               
                 Notch impact strength 
                 41 
                 25 
                 27 
                 44 
                 38 
                 37 
                 31 
                 30 
               
               
                 at −40° C. (KJ/M 2 ) 
               
               
                 Color difference measured 
                 1.1 
                 2.6 
                 2.7 
                 1.2 
                 1.7 
                 1.6 
                 2.1 
                 2.2 
               
               
                 after aging under a xenon 
               
               
                 lamp for 100 hours 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                   
                 Comparative 
                 Comparative 
                 Comparative 
                 Comparative 
                 Comparative 
                 Comparative 
               
               
                   
                   
                 Example 1 
                 Example 2 
                 Example 3 
                 Example 4 
                 Example 5 
                 Example 6 
               
               
                   
               
               
                 Polypropylene 
                 PP SP179 
                 60 
                 60 
                 60 
                 60 
                 60 
                 60 
               
               
                 resin 
               
               
                 Compatilizer 
                 PP-g-MAH 
                 3 
                 3 
                 3 
                 0 
                 0.2 
                 32 
               
               
                 Reinforcing 
                 Glass fibers 
                 30 
                 30 
                 30 
                 30 
                 30 
                 30 
               
               
                 fibers 
                 Quartz fibers 
               
               
                   
                 Basalt fibers 
               
               
                 Toughening 
                 POE 
                   
                 10 
               
               
                 agent 
               
               
                 Weather- 
                 UV-531 
                   
                 0.2 
               
               
                 resistant 
               
               
                 agent 
               
               
                 Low- 
                 Zinc white 
               
               
                 hardness 
                 Antimony 
                 0 
                   
                 28 
                 0.2 
                 0.2 
                 0.2 
               
               
                 colorant 
                 white 
               
               
                 powder 
                 Titanium 
               
               
                   
                 dioxide-1 
               
               
                   
                 Titanium 
               
               
                   
                 dioxide-2 
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Dosage of the reinforcing 
                   
                   
                   
                   
                   
                   
               
               
                 fibers added to the first 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
               
               
                 fibers added to the second 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                   
                 5 
                   
                   
                 15 
               
               
                 fibers added to the third 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                   
                   
                 15 
               
               
                 fibers added to the fourth 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                 15 
                 30 
                   
                   
                 10 
               
               
                 fibers added to the fifth 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                   
                   
                 10 
               
               
                 fibers added to the sixth 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
               
               
                 fibers added to the seventh 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                 10 
                   
                 5 
                   
                 20 
                 15 
               
               
                 fibers added to the eighth 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                   
                   
                   
                 15 
               
               
                 fibers added to the ninth 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
               
               
                 fibers added to the tenth 
               
               
                 section (part) 
               
               
                 Dosage of the reinforcing 
                 5 
                   
                 10 
               
               
                 fibers added to the die 
               
               
                 head (part) 
               
               
                 Percentage of Component I 
                 60 
                 87 
                 20 
                 78 
                 85 
                 75 
               
               
                 accounting for the number 
               
               
                 of reinforcing fibers (%) 
               
               
                 Percentage of Component II 
                 24 
                 5 
                 55 
                 4 
                 4 
                 15 
               
               
                 accounting for the number 
               
               
                 of reinforcing fibers (%) 
               
               
                 Percentage of Component III 
                 3 
                 8 
                 25 
                 2 
                 11 
                 3 
               
               
                 accounting for the number 
               
               
                 of reinforcing fibers (%) 
               
               
                 Notch impact strength 
                 12 
                 18 
                 10 
                 8 
                 8.5 
                 9.2 
               
               
                 at normal temperature (KJ/M 2 ) 
               
               
                 Notch impact strength 
                 4 
                 8 
                 3 
                 2.5 
                 2.8 
                 4.2 
               
               
                 at −40° C. (KJ/M 2 ) 
               
               
                 Color difference measured 
                 5 
                 2.0 
                 4 
                 2.2 
                 2.3 
                 5.0 
               
               
                 after aging under a xenon 
               
               
                 lamp for 100 hours