Antioxidant low-melting high-transparency polypropylene additive and preparation process thereof

Abstract

The antioxidant low-melting-point high-transparency polypropylene additive is prepared from the following components in parts by mass: 8 to 12 parts of novel composite antioxidant, 5 to 8 parts of nano silicon dioxide aerogel, 3 to 7 parts of nano calcium carbonate whisker, 10 to 15 parts of low-melting-point copolyamide, 2 to 4 parts of organic montmorillonite, 1 to 3 parts of zinc stearate and 1 to 3 parts of nucleating agent. The polypropylene additive has the beneficial effects that through compounding of the novel composite antioxidant, the synergistic effect of the hindered phenol antioxidant and the phosphite antioxidant is exerted, the oxidation resistance of the polypropylene additive is remarkably improved, and the service life of a polypropylene material is prolonged; by adding the nano silicon dioxide aerogel and the organic montmorillonite, a unique gas barrier structure is formed, permeation of gas molecules is effectively hindered, and the gas barrier property of the polypropylene material is greatly improved; through the synergistic effect of the nano calcium carbonate whisker and the novel organic nucleating agent, the crystallization process of polypropylene is optimized, so that fine and uniform crystals are formed from polypropylene.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polypropylene additives, and particularly relates to an antioxidant low-melting high-transparency polypropylene additive and a preparation process. BACKGROUND

[0002] Polypropylene additives are auxiliary materials combined with polypropylene matrix through physical or chemical methods, and the core functions thereof include: compensating for the natural defects of polypropylene in heat resistance, impact resistance, and aging resistance; endowing polypropylene with special properties such as flame retardation, electrical conductivity, and antibiosis; and reducing processing energy consumption and improving production efficiency. At present, a polypropylene compounded additive and a preparation method and application thereof are disclosed in patent publication CN119684683A, which includes the following components by mass fraction: antioxidant 2-5 parts, core-shell type aluminum oxide 2-8 parts, fluorophosphonate 0.1-4 parts, lubricant 1-3 parts, stearate 1-3 parts, and nucleating agent 1-2 parts. The preparation method includes the following steps: according to the proportion, the antioxidant, the core-shell type aluminum oxide, the fluorophosphonate, the lubricant, the stearate, and the nucleating agent are mixed and put into a high-speed disperser to be high-speed dispersed to obtain a mixture; then the mixture is put into a ball mill to be finely dispersed to obtain a finely dispersed material; and the finely dispersed material is put into a granulator to be granulated to obtain the polypropylene compounded additive. However, the additive still has room for improvement in the comprehensive improvement of gas barrier property, transparency, and antioxidant performance. SUMMARY

[0003] The application aims to provide an antioxidant low-melting high-transparency polypropylene additive and a preparation process, solve the deficiencies of the existing polypropylene additive in gas barrier property, transparency, and antioxidant performance, and realize the comprehensive improvement of the performance of polypropylene materials.

[0004] To achieve the above-mentioned purpose, the application provides the following technical scheme: an antioxidant low-melting high-transparency polypropylene additive, including the following components by mass fraction: a novel composite antioxidant 8-12 parts, nano-silica aerogel 5-8 parts, nano-calcium carbonate whisker 3-7 parts, low-melting point copolyamide 10-15 parts, organic montmorillonite 2-4 parts, zinc stearate 1-3 parts, and nucleating agent 1-3 parts.

[0005] As a preferred technical scheme of the application, the novel composite antioxidant is compounded by a hindered phenolic antioxidant and a phosphite antioxidant at a mass ratio of 3:2.

[0006] As a preferred technical scheme of the application, the preparation method of the nucleating agent is as follows: Prepare hexamethylol melamine, stannous octoate, propiolactone, acid anhydride, pyridine, metal oxide, or metal hydroxide; The hexamethylol melamine and stannous octoate are added into the lactide in a molten state, and the reaction is carried out at a temperature of 140-170 DEG C for 12-24 hours to obtain compound one; The anhydride is added into pyridine, stirred at 105-120 DEG C until the anhydride is completely dissolved, then added into compound one, and the reaction is continuously stirred until the reaction is completed, then the reaction product is poured into deionized water for precipitation and washing to remove unreacted raw materials and small molecular by-products generated in the reaction, the precipitate is obtained by centrifugal separation, and the precipitate is dried in a vacuum drying box at 50-60 DEG C for 8-12 hours to obtain compound two; The compound two is mixed with metal oxide or metal hydroxide, and the mixing is carried out in a banbury mixer at a mixing temperature of 160-190 DEG C.

[0007] As a preferred technical solution of the present application, the hexamethylol melamine and stannous octoate are added into the lactide in a molten state, and the reaction is carried out at a temperature of 140-170 DEG C for 12-24 hours to obtain compound one, and the reaction is carried out in a nitrogen atmosphere.

[0008] As a preferred technical solution of the present application, the centrifugal speed is set to 3000-4000 r / min, and the centrifugal time is 10-15 min.

[0009] As a preferred technical solution of the present application, the average particle size of the nano-silica aerogel is 5-20 nm.

[0010] The application further discloses a preparation process of the antioxidant low-melting high-transparency polypropylene additive. The new composite antioxidant, nano-silica aerogel, nano-calcium carbonate whisker, low-melting point copolyamide, organic montmorillonite, zinc stearate and nucleating agent are put into a high-speed mixer according to a proportion, mixed at a rotating speed of 800-1200 r / min at 80-100 DEG C for 15-25 min to obtain a premix; The premix is put into a double-screw extruder, the temperature of the first zone of the double-screw extruder is controlled to be 160-170 DEG C, the temperature of the second zone is controlled to be 170-180 DEG C, the temperature of the third zone is controlled to be 180-190 DEG C, the temperature of the fourth zone is controlled to be 190-200 DEG C, the temperature of the fifth zone is controlled to be 200-210 DEG C, and the screw rotating speed is controlled to be 200-300 r / min, so that the premix is melt blended and extruded to obtain an extruded material; The extruded material is cut into particles by an air-cooled granulator.

[0011] As a preferred technical solution of the present application, the cutting speed of the air-cooled granulator is 80-120 r / min.

[0012] Compared with the prior art, the application has the beneficial effects that: By compounding the new type of composite antioxidant, the synergistic effect of the hindered phenolic antioxidant and the phosphite antioxidant is exerted, the antioxidant performance of the polypropylene additive is significantly improved, and the service life of the polypropylene material is prolonged. The addition of the nanometer silicon dioxide aerogel and the organic montmorillonite forms a unique gas barrier structure, effectively hinders the penetration of gas molecules, and greatly improves the gas barrier property of the polypropylene material. The synergistic effect of the nanometer calcium carbonate whisker and the new type of organic nucleating agent optimizes the crystallization process of the polypropylene, makes the polypropylene form fine and uniform crystals, significantly improves the transparency of the material, and meets the demand for transparent polypropylene products. The addition of the low-melting-point copolyamide reduces the melting temperature of the polypropylene, improves the processing performance of the polypropylene, reduces the processing energy consumption, and improves the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The preparation process flowchart of the application is shown in the following table. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0015] Embodiment 1 Please refer to Figure 1 The first embodiment of the application provides an antioxidant low-melting high-transparency polypropylene additive, which comprises the following components in parts by mass: 8 parts of a new type of composite antioxidant, 5 parts of nanometer silicon dioxide aerogel, 3 parts of nanometer calcium carbonate whisker, 10 parts of low-melting-point copolyamide, 2 parts of organic montmorillonite, 1 part of zinc stearate and 1 part of nucleating agent. The nanometer calcium carbonate whisker promotes the formation of fine and uniform crystals in the crystallization process of the polypropylene by utilizing its unique crystal nucleus effect, thereby improving the transparency of the material. The low-melting-point copolyamide reduces the melting temperature of the polypropylene and improves the processing performance. The sheet structure of the organic montmorillonite can form a barrier layer in the polypropylene matrix, further enhancing the gas barrier property. The zinc stearate serves as a lubricant to reduce the frictional resistance of the additive during the processing. The nucleating agent is a new type of organic nucleating agent, which further optimizes the crystallization behavior of the polypropylene, improves the crystallization rate and the crystallinity.

[0016] In the embodiment, preferably, the novel composite antioxidant is compounded by the hindered phenolic antioxidant and the phosphite antioxidant at a mass ratio of 3:2, the hindered phenolic antioxidant can capture free radicals, the phosphite antioxidant can decompose hydroperoxide, and the two can work together to significantly improve the antioxidant performance.

[0017] In the embodiment, preferably, the average particle size of the nanosilica aerogel is 5 nm, the nanosilica aerogel has extremely low density and high porosity, can effectively hinder the diffusion of gas molecules, and improves the gas barrier property In the embodiment, preferably, the preparation method of the nucleating agent is as follows: Prepare hexamethylol melamine, stannous octoate, lactide, acid anhydride, pyridine, metal oxide or metal hydroxide; Add the hexamethylol melamine and the stannous octoate into the lactide in a molten state, and react for 24 h under the condition of a temperature of 140 ℃, so that the compound one is obtained, and the reaction is carried out under the atmosphere of nitrogen protection; Add the acid anhydride into the pyridine, stir at 105 ℃ until the acid anhydride is completely dissolved, then add into the compound one, continue to stir and react, after the reaction is completed, pour the reaction product into deionized water for precipitation and washing, remove the unreacted raw materials and small molecular by-products generated in the reaction process, obtain the precipitate by centrifugal separation, set the centrifugal speed to 3000 r / min, and set the centrifugal time to 15 min, place the precipitate in a vacuum drying box, dry at 50 ℃ for 12 h, and obtain the compound two; Mix the compound two with the metal oxide or the metal hydroxide, and perform banburying in a banburying machine, and control the banburying temperature to be 160 ℃.

[0018] A preparation process of an antioxidant low-melting high-transparency polypropylene additive comprises the following steps: Put the novel composite antioxidant, the nanosilica aerogel, the nanometer calcium carbonate whisker, the low-melting copolyamide, the organic montmorillonite, the zinc stearate and the nucleating agent into a high-speed mixer according to the proportion, mix at 80 ℃ and at a rotating speed of 1200 r / min for 25 min, and obtain a premix; Put the premix into a double-screw extruder, control the temperature of the first zone of the double-screw extruder to be 160 ℃, the temperature of the second zone to be 170 ℃, the temperature of the third zone to be 180 ℃, the temperature of the fourth zone to be 190 ℃, the temperature of the fifth zone to be 200 ℃, and the rotating speed of the screw to be 200 r / min, perform melt blending extrusion, and obtain an extruded material; Cut the extruded material into particles by an air-cooled granulator, and the cutting speed is 80 r / min.

[0019] Embodiment 2 Please refer to Figure 1 As the second embodiment of the present application, the embodiment is based on the previous embodiment, and the difference is that: An antioxidant low-melting high-transparency polypropylene additive, comprising the following components by mass fraction: 10 parts of a new composite antioxidant, 7 parts of nano-silica aerogel, 5 parts of nano-calcium carbonate whisker, 13 parts of low-melting copolyamide, 3 parts of organic montmorillonite, 2 parts of zinc stearate, and 2 parts of nucleating agent; the nano-calcium carbonate whisker promotes the formation of fine and uniform crystals in the polypropylene crystallization process by virtue of its unique crystal nucleus effect, thereby improving the transparency of the material; the low-melting copolyamide reduces the melting temperature of the polypropylene and improves the processing performance; the organic montmorillonite forms a barrier layer in the polypropylene matrix to further enhance the gas barrier property; the zinc stearate serves as a lubricant to reduce the frictional resistance of the additive during the processing; and the nucleating agent is a new organic nucleating agent, which further optimizes the crystallization behavior of the polypropylene and improves the crystallization rate and crystallinity.

[0020] In this embodiment, the average particle size of the nano-silica aerogel is preferably 12 nm, which has extremely low density and high porosity, can effectively hinder the diffusion of gas molecules, and improve the gas barrier property.

[0021] In this embodiment, the nucleating agent is prepared by the following method: Prepare hexamethylol melamine, stannous octoate, lactide, acid anhydride, pyridine, metal oxide or metal hydroxide; Add the hexamethylol melamine and the stannous octoate to the lactide in a molten state, and react at a temperature of 155℃ for 18h, thereby obtaining compound one, and the reaction is carried out in a nitrogen atmosphere; Add the acid anhydride to the pyridine and stir at 112℃ until the acid anhydride is completely dissolved; then, add to the compound one and continue to stir and react; after the reaction is completed, pour the reaction product into deionized water for precipitation and washing to remove unreacted raw materials and small molecular by-products generated during the reaction; the precipitate is obtained by centrifugal separation at a centrifugal speed of 3500r / min for 13min; and the precipitate is dried in a vacuum drying oven at 55℃ for 10h to obtain compound two; Mix the compound two with the metal oxide or the metal hydroxide, and perform mixing in a banbury mixer at a mixing temperature of 175℃.

[0022] A preparation process of an antioxidant low-melting high-transparency polypropylene additive, comprising the following steps: Put the new composite antioxidant, nano-silica aerogel, nano-calcium carbonate whisker, low-melting copolyamide, organic montmorillonite, zinc stearate, and nucleating agent into a high-speed mixer in a proportioning manner, mix at a speed of 1000r / min at 90℃ for 20min to obtain a premix; The premix is put into a double screw extruder, the temperature of the first zone of the double screw extruder is controlled at 165 DEG C, the temperature of the second zone is controlled at 175 DEG C, the temperature of the third zone is controlled at 185 DEG C, the temperature of the fourth zone is controlled at 195 DEG C, the temperature of the fifth zone is controlled at 205 DEG C, and the screw rotation speed is 250 r / min, so that the extrusion is carried out by melt blending, and the extruded material is obtained; The extruded material is granulated by air cooling granulator, and the granulation speed is 100 r / min.

[0023] Example 3 Please refer to Figure 1 For the third embodiment of the present application, the embodiment is based on the previous embodiment, and the difference is that: The antioxidant low-melting high-transparency polypropylene additive comprises the following components in parts by mass: 12 parts of a novel composite antioxidant, 8 parts of nano-silica aerogel, 7 parts of nano-calcium carbonate whisker, 15 parts of low-melting copolyamide, 4 parts of organic montmorillonite, 3 parts of zinc stearate, and 3 parts of nucleating agent. The nano-calcium carbonate whisker promotes the formation of fine and uniform crystals in the polypropylene crystallization process by utilizing its unique crystal nucleus effect, thereby improving the transparency of the material. The low-melting copolyamide reduces the melting temperature of the polypropylene and improves the processing performance. The sheet structure of the organic montmorillonite can form a barrier layer in the polypropylene matrix, further enhancing the gas barrier property. The zinc stearate serves as a lubricant to reduce the frictional resistance of the additive during the processing. The nucleating agent is a novel organic nucleating agent, which further optimizes the crystallization behavior of the polypropylene, improves the crystallization rate and crystallinity.

[0024] In this embodiment, preferably, the average particle size of the nano-silica aerogel is 20 nm, which has extremely low density and high porosity, can effectively hinder the diffusion of gas molecules, and improve the gas barrier property.

[0025] In this embodiment, preferably, the preparation method of the nucleating agent is as follows: Prepare hexamethylol melamine, stannous octoate, lactide, acid anhydride, pyridine, metal oxide or metal hydroxide; The hexamethylol melamine and the stannous octoate are added to the lactide in a molten state, and the reaction is carried out at a temperature of 170 DEG C for 12 hours, so as to obtain compound one, and the reaction is carried out in a nitrogen atmosphere. The acid anhydride is added to the pyridine and stirred at 120 DEG C until the acid anhydride is completely dissolved; then, it is added to the compound one and continues to be stirred and reacted. After the reaction is completed, the reaction product is poured into deionized water for precipitation and washing to remove unreacted raw materials and small molecular by-products generated in the reaction process. The precipitation is obtained by centrifugal separation, the centrifugal speed is set to 4000 r / min, and the centrifugal time is 10 min. The precipitation is placed in a vacuum drying oven and dried at 60 DEG C for 8 hours to obtain compound two. Mixing compound two with metal oxide or metal hydroxide, and mixing in an internal mixer, the mixing temperature is controlled at 190℃.

[0026] A preparation process of an antioxidant low-melting high-transparency polypropylene additive, comprising the following steps: The new composite antioxidant, nano-silica aerogel, nano-calcium carbonate whisker, low-melting copolyamide, organic montmorillonite, zinc stearate and nucleating agent are put into a high-speed mixer according to the proportion, mixed at 100℃ and 1200r / min for 15min to obtain a premix; The premix is put into a double-screw extruder, the temperature of the first zone of the double-screw extruder is controlled at 170℃, the temperature of the second zone is controlled at 180℃, the temperature of the third zone is controlled at 190℃, the temperature of the fourth zone is controlled at 200℃, the temperature of the fifth zone is controlled at 210℃, and the screw rotation speed is 300r / min, so that the extrusion is carried out by melting and blending to obtain an extruded material; The extruded material is granulated by air-cooled granulator, and the granulation speed is 120r / min.

[0027] In order to verify the advantages of the polypropylene additive in the aspects of antioxidant property, gas barrier property, transparency and processing performance, the following comparative experiments are designed and the experimental data are arranged as follows: Table 1: Comparison of antioxidant properties (oxidation induction time OIT test) Sample OIT@200℃ (min) Blank PP 12.3 Comparative Example CN119684683A 28.5 Example 1 45.8 Example 2 52.4 Example 3 49.6 Conclusion: The additive of the application significantly prolongs the oxidation induction period, and the oxidation induction period of example 2 is improved by 83.9% compared with the comparative example, which proves the synergistic effect of the hindered phenol / phosphite composite antioxidant.

[0028] Table 2: Comparison of oxygen barrier properties (oxygen transmission rate OTR) Sample OTR (cm3 / m2·24h·0.1MPa) Blank PP 1480 Comparative Example CN119684683A 920 Example 1 580 Example 2 430 Example 3 510 Conclusion: The nano-silica aerogel and the organic montmorillonite synergistically construct a barrier network, and the oxygen transmission rate of example 2 is reduced by 53.3% compared with the comparative example.

[0029] Table 3: Comparison of optical properties (transmittance and haze) Sample Transmittance (%) Haze (%) Blank PP 88.2 45.6 Comparative Example CN119684683A 90.5 28.3 Example 1 93.8 12.7 Example 2 95.1 9.4 Example 3 94.3 10.9 Conclusion: The nano-calcium carbonate whisker and the nucleating agent synergistically refine the crystal, the transmittance of example 2 is improved to 95.1%, the haze is reduced to 9.4%, and the transparency is significantly better than that of the comparative example.

[0030] Table 4: Comparison of processing performance (melt index MFI) Sample MFI@230℃ (g / 10min) Blank PP 18.5 Comparative Example CN119684683A 25.3 Example 1 34.7 Example 2 38.2 Example 3 36.9 Conclusion: The low-melting copolyamide effectively improves the fluidity, and the melt index of example 2 is improved by 51.0% compared with the comparative example, and the processing energy consumption is significantly reduced.

[0031] Table 5: Comprehensive performance comparison (Example 2 vs. Comparative Example CN119684683A) Performance Index Comparative Example CN119684683A Example 2 Promotion Range OIT (min) 28.5 52.4 +83.9% OTR (cm 3 / m 2 ·d)]]> 920 430 -53.3% Transmittance (%) 90.5 95.1 +5.1% Haze (%) 28.3 9.4 -66.8% MFI (g / 10min) 25.3 38.2 +51.0% Experimental condition explanation: Sample preparation: 5 wt% additives were blended with PP matrix (homopolymer PP, melt index 25 g / 10min) and then pressed into film (0.2mm thickness) or standard test bars; Test standards: OIT: ISO 11357-6 (200℃, O2 atmosphere) OTR: ASTM D3985 (23℃, 50%RH) Transmittance / haze: ASTM D1003 (integrating sphere method) MFI: ASTM D1238 (230℃ / 2.16kg) Conclusion: Through component optimization and synergistic effect, the application is significantly superior to the prior art in terms of antioxidant property, gas barrier property, transparency and processing performance, and meets the comprehensive performance requirements of polypropylene materials in high requirement application scenarios.

[0032] Although embodiments of the application have been shown and described, it is to be understood that various modifications, substitutions, replacements and variations can be made to these embodiments without departing from the principles and spirit of the application, and the scope of the application is defined by the appended claims and their equivalents.

Claims

1. An antioxidant low-melting, high-transparency polypropylene additive, characterized by: The invention comprises the following components in parts by mass: 8-12 parts of a new composite antioxidant, 5-8 parts of nano-silicon dioxide aerogel, 3-7 parts of nano-calcium carbonate whiskers, 10-15 parts of a low-melting-point copolyamide, 2-4 parts of organic montmorillonite, 1-3 parts of zinc stearate and 1-3 parts of a nucleating agent.

2. The antioxidant low-melting, high-transparency polypropylene additive according to claim 1, characterized in that: The novel composite antioxidant is prepared by compounding a hindered phenol antioxidant and a phosphite antioxidant in a mass ratio of 3:

2.

3. The antioxidant low-melting, high-transparency polypropylene additive according to claim 1, characterized in that: The preparation method of the nucleating agent is as follows: preparing hexahydroxymethylmelamine, stannous octoate, lactide, acid anhydride, pyridine, metal oxide or metal hydroxide; Hexahydroxymethylmelamine and stannous octoate are added to molten lactide, and the mixture is reacted at a temperature of 140-170° C. for 12-24 hours to obtain compound 1; The acid anhydride is added to pyridine and stirred at 105-120°C until the acid anhydride is completely dissolved; then, the mixture is added to compound 1 and the reaction is continued with stirring. After the reaction is completed, the reaction product is poured into deionized water for precipitation and washing to remove unreacted raw materials and small molecular byproducts generated during the reaction. The precipitate is obtained by centrifugation and placed in a vacuum drying oven at 50-60°C for 8-12 hours to obtain compound 2; The compound 2 is mixed with the metal oxide or metal hydroxide, and kneaded in an internal mixer at a temperature of 160-190°C.

4. The antioxidant low-melting, high-transparency polypropylene additive according to claim 3, characterized in that: Hexahydroxymethylmelamine and stannous octoate are added to molten lactide, and the reaction is carried out at a temperature of 140-170° C. for 12-24 hours to obtain compound 1. The reaction is carried out under a nitrogen atmosphere.

5. The antioxidant low-melting, high-transparency polypropylene additive according to claim 3, characterized in that: The centrifugal speed is set to 3000-4000 r / min and the centrifugal time is 10-15 min.

6. The antioxidant low-melting, high-transparency polypropylene additive according to claim 1, characterized in that: The average particle size of the nano-silica aerogel is 5-20 nm.

7. The process for preparing an antioxidant low-melting, high-transparency polypropylene additive according to any one of claims 1 to 6, characterized in that: The steps include: The novel composite antioxidant, nano-silica aerogel, nano-calcium carbonate whiskers, low-melting-point copolyamide, organic montmorillonite, zinc stearate and nucleating agent are added into a high-speed mixer according to a certain ratio, and mixed at 800-1200 r / min for 15-25 minutes at 80-100° C. to obtain a premix; The premix is ​​put into a twin-screw extruder, and the temperature of the first zone of the twin-screw extruder is controlled to be 160-170° C., the temperature of the second zone is 170-180° C., the temperature of the third zone is 180-190° C., the temperature of the fourth zone is 190-200° C., the temperature of the fifth zone is 200-210° C., and the screw speed is 200-300 r / min, and melt-blending and extruding are performed to obtain an extrudate; The extrudate is pelletized by an air-cooled pelletizer.

8. The process for preparing an antioxidant low-melting, high-transparency polypropylene additive according to claim 7, characterized in that: The pelletizing speed of the air-cooled pelletizer is 80-120r / min.

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