Modified polypropylene material and method for producing the same

Abstract

The application discloses a modified polypropylene material and a preparation method thereof, and belongs to the technical field of polypropylene materials. According to weight parts, the modified polypropylene material comprises the following raw materials: 100 parts of polypropylene resin, 30-40 parts of maleic anhydride grafted polypropylene, 25-35 parts of nano calcium carbonate, 10-14 parts of additives and 2-3 parts of silane coupling agent. The raw materials are mixed in a high-speed mixer according to the proportion, discharged and cooled, and then sent into a double-screw extruder to be melt-extruded, cooled and granulated, so that the modified polypropylene material is prepared. The polypropylene is modified by using the synthetic additives, so that the modified polypropylene material has the modification effects of flame retardation, aging resistance and mechanical strength, and the additives themselves have chemical bond effects with the polypropylene matrix, so that the defects of migration resistance and bleeding resistance of the functional components are effectively improved, and the functional stability and durability of the modified polypropylene material are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polypropylene materials, and in particular relates to a modified polypropylene material and a preparation method thereof. BACKGROUND

[0002] Polypropylene is a thermoplastic resin prepared by polymerization of propylene monomer. The stereoregular polypropylene has good general performance, good heat resistance, good stress cracking resistance and good rigidity, is easy to process and mold, and has low raw material price, and has wide application value. Polypropylene is a common general-purpose plastic, which can be used in the fields of household appliances, automobiles, transportation, etc. However, polypropylene material is flammable, which has safety hazards. Generally, a flame retardant is added to the raw material formula to solve this problem. Among them, halogen flame retardants are most widely used in polypropylene materials, but the release of halogen into the atmosphere will pollute the environment; it is of great significance to find a green and environmentally friendly flame retardant for polypropylene material.

[0003] For example, the prior art CN107216542A discloses a halogen-free flame-retardant polypropylene material, which is composed of the following components by weight: polypropylene resin 100 parts, halogen-free composite flame retardant 20-35 parts, toughening agent 5-20 parts, and composite antioxidant 0.05-0.12 parts. The halogen-free composite flame retardant is composed of dipiperazine diphosphate, pentaerythritol diphosphate melamine salt, melamine cyanurate and organic montmorillonite in a weight ratio of (8-15):(6-16):(2-3):(2-2.5). The invention adopts dipiperazine diphosphate, pentaerythritol diphosphate melamine salt, melamine cyanurate and organic montmorillonite to form a halogen-free composite flame-retardant system, which has good flame-retardant synergistic effect and good high-temperature resistance. Although the flame-retardant composite system meets environmental protection requirements, the interaction between the above flame-retardant components and the PP matrix is relatively low, which not only has a negative impact on the mechanical properties of the polypropylene material, but also is prone to migration and exudation, and it is difficult to ensure the durability of the flame-retardant effect. In addition, the polypropylene material has relatively poor ultraviolet aging resistance, which needs to be further improved. SUMMARY

[0004] The present application aims to overcome the defects of the prior art and provides a modified polypropylene material and a preparation method thereof.

[0005] The present application uses a synthetic additive to modify polypropylene, which not only realizes the modification effect of flame retardation, aging resistance and mechanical strength of the polypropylene material, but also effectively improves the defects of migration resistance and exudation resistance of the functional components due to the chemical bond between the additive itself and the polypropylene matrix.

[0006] The object of the present application can be achieved by the following technical solutions:

[0007] A modified polypropylene material, comprising the following raw materials in parts by weight: polypropylene resin 100 parts, maleic anhydride grafted polypropylene 30-40 parts, nano calcium carbonate 25-35 parts, additives 10-14 parts, silane coupling agent 2-3 parts, benzoyl peroxide 0.3-0.4 parts;

[0008] A preparation method of the modified polypropylene material, comprising the following steps:

[0009] (1) The raw materials are poured into a high-speed mixer according to the ratio and mixed until the friction heat generated by the mixing raises the temperature of the materials to 90-100℃, and then the materials are discharged and cooled;

[0010] (2) The cooled mixed materials are sent into a double-screw extruder for melt extrusion, the extruded strip is cooled in a water tank, drawn into a granulator, and then granulated to obtain the modified polypropylene material.

[0011] Further, the silane coupling agent is silane coupling agent KH304 or silane coupling agent KH303, which can promote the uniform dispersion of nano calcium carbonate in the polypropylene material.

[0012] Further, the additives are prepared by the following steps:

[0013] S1, in a three-necked flask equipped with a stirrer, a thermometer and a condenser, nitrogen is continuously introduced for 10 min (to replace the air in the flask), hexachlorocyclotriphosphazene, dioxane and N,N-dimethylaniline are added, stirred and dissolved uniformly, then 2-chloro-1,3-propanediol dioxane solution is added dropwise, the reaction temperature is controlled not to exceed 40℃ during the dropwise addition, after the dropwise addition is completed, the temperature is raised to 100℃, and the reaction is kept for 15 h, then the temperature is lowered to below 30℃, the generated N,N-dimethylaniline hydrochloride is removed by filtration, the filtrate is distilled under reduced pressure to remove dioxane, washed with distilled water twice, and then the lower organic phase is separated, then ethyl acetate is added, dried with anhydrous sodium sulfate, filtered, and the filtrate is distilled under reduced pressure to remove ethyl acetate, to obtain intermediate 1; the amount ratio of hexachlorocyclotriphosphazene, N,N-dimethylaniline and 2-chloro-1,3-propanediol is 10.4g:21.8g:11.1g;

[0014] Hexachlorocyclotriphosphazene and 2-chloro-1,3-propanediol undergo substitution and cyclization reaction to obtain intermediate 1, and the process is as follows:

[0015]

[0016] S2, add propylenediamine, triethylamine, acetone and hexane into a three-neck flask equipped with stirring device and condensing device, stir and dissolve uniformly, and place the flask in an ice water bath to control the temperature of the system to be no more than 2℃, then slowly drop 8-chloro-1-octene, remove the ice bath after the drop is completed, and react at room temperature for 2h, after the reaction is completed, filter (remove the generated salt), take the organic phase (liquid phase), wash with 20% NaCl aqueous solution for 4-5 times, dry with anhydrous Mg2SO4, filter, and finally remove the solvent (hexane) by reduced pressure distillation to obtain intermediate 2; the amount ratio of propylenediamine, triethylamine and 8-chloro-1-octene is 8.2g:10.1g:14.7g;

[0017] Under the action of triethylamine, -NH2 on the propylenediamine molecule and the chlorine group on the 8-chloro-1-octene molecule undergo nucleophilic substitution reaction, by controlling the molar ratio of the two to be close to 1:1 and the propylenediamine to be slightly excessive, a substitution reaction occurs, and intermediate 2 is obtained, and the process is as shown below:

[0018]

[0019] S3, add intermediate 2, pyridine and ether into a three-neck flask equipped with stirring device and reflux condensing device, stir and dissolve uniformly, then add 2-hydroxybenzaldehyde to the system, heat to 62℃ and react for 5h, after the reaction is completed, remove most of the solvent by rotary evaporation, purify by column chromatography (the eluent is cyclohexane / ethyl acetate, and the volume ratio of the two is 1:1), spin dry the eluent, and obtain intermediate 3; the amount ratio of intermediate 2 and 2-hydroxybenzaldehyde is 18.4g:12.2g;

[0020] -NH2 on the intermediate 2 molecule and -CHO on the 2-hydroxybenzaldehyde molecule undergo aldehyde amine condensation reaction to obtain intermediate 3, and the process is as shown below:

[0021]

[0022] S4, remove the air in the four-neck flask with N2, then add intermediate 3 and DMF (N,N-dimethylformamide), stir and mix uniformly, control the temperature in the flask to be 35-40℃, slowly drop the mixture of intermediate 1, triethylamine and DMF under stirring, continue to react at 40℃ for 4h after the drop is completed, naturally cool to room temperature after the reaction is completed, add a large amount of deionized water, precipitate the organic matter, and finally dry the obtained organic matter to obtain the additive; the amount ratio of intermediate 3, intermediate 1 and triethylamine is 28.8g:13.8g:9.1g;

[0023] Under the action of triethylamine, -NH- on the intermediate 3 molecule and -Cl on the intermediate 1 molecule undergo nucleophilic substitution reaction to obtain the additive, and the reaction process is as shown below:

[0024]

[0025] The obtained additive dendrimer has a four-membered chelate ring structure composed of a phosphorus-nitrogen six-membered ring and a phosphorus-oxygen six-membered ring, the phosphorus-nitrogen six-membered ring constitutes a P-N type synergistic flame-retardant component, the flame-retardant component has high and safe flame-retardant performance, and the four-membered chelate ring structure has relatively high rigidity and relatively high stability, which can not only improve the rigidity of the polypropylene material, but also improve the heat resistance of the polypropylene material; the long fatty chain and the benzene ring-containing molecular chain distributed on the periphery of the four-membered chelate ring structure are distributed in a dendritic manner, the long fatty chain has extremely high flexibility, can be flexibly inserted between polypropylene molecular chains, and the end of the long fatty chain is an unsaturated carbon-carbon double bond, which can participate in the crosslinking process of polypropylene under the action of a small amount of initiator, thereby promoting the generation of a crosslinking network structure, which can not only improve the mechanical strength of the polypropylene material, but also improve the wear resistance and water resistance of the polypropylene material; in addition, the end of the benzene ring-containing molecular chain is a benzene ring, which contains a phenolic hydroxyl group, the phenolic hydroxyl group itself has good antioxidant performance, in addition, the phenolic hydroxyl group and the N atom on the chain form an intramolecular hydrogen bond, thereby forming a stable six-membered ring structure, which can effectively absorb ultraviolet rays (the hydrogen bond in the six-membered ring is broken due to thermal vibration, the six-membered ring is opened, forming an ion compound in a high-energy unstable state, and in the process of returning to a stable ground state, the ion compound releases excess energy through thermal energy or radiation energy, and the six-membered ring is re-closed, thereby achieving the absorption of ultraviolet rays in the reversible process), so the structure can give the polypropylene material good anti-aging effect.

[0026] Therefore, the additive can realize the modification effect of the polypropylene material in terms of flame retardation, anti-aging and mechanical strength, and it needs to be supplemented that, since the additive itself has a chemical bond with the polypropylene matrix, the flame-retardant component and the anti-aging component have good bonding force with the matrix, compared with the direct addition of flame-retardant and anti-aging components, the defects of the migration resistance and the bleeding resistance of the functional components can be effectively improved.

[0027] Advantages of the present application:

[0028] The present application modifies the polypropylene by using the synthesized additive, which can not only realize the modification effect of the polypropylene material in terms of flame retardation, anti-aging and mechanical strength, but also effectively improve the defects of the migration resistance and the bleeding resistance of the functional components due to the chemical bond between the additive itself and the polypropylene matrix; thereby improving the functional stability and durability of the modified polypropylene material, and the obtained polypropylene material has important application value. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0030] Embodiment 1

[0031] Preparation of the additive:

[0032] S1, 10.4 g of hexachlorocyclotriphosphazene, 100 mL of dioxane and 21.8 g of N, N-dimethyl aniline were added into a three-neck flask equipped with a stirrer, a thermometer and a condenser, and nitrogen was continuously introduced for 10 min (to replace the air in the flask), and then 11.1 g of a 2-chloro-1, 3-propanediol dioxane solution was added dropwise, the reaction temperature was controlled to be not higher than 40 DEG C during the dropwise addition, and then the temperature was increased to 100 DEG C after the dropwise addition was completed, and the reaction was maintained for 15 h, and then the temperature was decreased to below 30 DEG C, and N, N-dimethyl aniline hydrochloride generated was removed by filtration, the filtrate was distilled under reduced pressure to remove dioxane, washed with distilled water twice, and then the lower organic phase was separated, and then ethyl acetate was added, dried with anhydrous sodium sulfate, and filtered under suction, and the filtrate was distilled under reduced pressure to remove ethyl acetate, to obtain intermediate 1;

[0033] S2, 8.2 g of propylenediamine, 10.1 g of triethylamine, 50 mL of acetone and 50 mL of hexane were added into a three-neck flask equipped with a stirring device and a condensing device, and stirred and dissolved uniformly, and the flask was placed in an ice water bath, and the temperature of the system was controlled to be not higher than 2 DEG C, and then 14.7 g of 8-chloro-1-octene was slowly added dropwise, and after the dropwise addition was completed, the ice bath was removed, and the reaction was carried out at room temperature for 2 h, and after the reaction was completed, filtration was carried out (to remove the generated salt), and the organic phase (liquid phase) was taken, washed with a 20% NaCl aqueous solution for 4 times, dried with anhydrous Mg2SO4, filtered, and finally distilled under reduced pressure to remove the solvent (hexane), to obtain intermediate 2;

[0034] S3, 18.4 g of intermediate 2, 50 mL of pyridine and 40 mL of ethyl ether were added into a three-neck flask equipped with a stirring device and a reflux condensing device, and stirred and dissolved uniformly, and then 12.2 g of 2-hydroxybenzaldehyde was added into the system, and the temperature was increased to 62 DEG C, and the reaction was carried out for 5 h, and after the reaction was completed, most of the solvent was removed by rotary evaporation, and column chromatography was adopted for purification (the eluent was cyclohexane / ethyl acetate, and the volume ratio of the two was 1:1), and the eluent was rotary evaporated, to obtain intermediate 3;

[0035] S4, remove the air in the four-necked flask with N2, then add 28.8 g of intermediate 3 and 120 mL of DMF, stir to mix well, control the temperature in the flask at 35-40 °C, slowly drop 13.8 g of intermediate 1, 9.1 g of triethylamine and 30 mL of DMF into the mixture under stirring, continue to react at 40 °C for 4 h after the dropping is completed, then naturally cool to room temperature, add a large amount of deionized water, precipitate the organic matter, and finally dry the obtained organic matter to obtain the additive.

[0036] Example 2

[0037] Preparation of the additive:

[0038] S1, in a three-necked flask equipped with a stirrer, a thermometer and a condenser, after 10 min of continuous nitrogen gas input (to replace the air in the flask), 20.8 g of hexachlorocyclotriphosphazene, 200 mL of dioxane and 43.6 g of N,N-dimethyl aniline were added, stirred to dissolve uniformly, then 22.2 g of 2-chloro-1,3-propanediol solution in dioxane was added dropwise, the reaction temperature was controlled not to exceed 40 °C during the dropping process, then the temperature was raised to 100 °C after the dropping was completed, and the reaction was maintained for 15 h, then the temperature was lowered to below 30 °C, and the generated N,N-dimethyl aniline hydrochloride was removed by filtration, the filtrate was distilled under reduced pressure to remove dioxane, washed with distilled water twice, and then the lower organic phase was separated, followed by the addition of ethyl acetate, dried with anhydrous sodium sulfate, filtered and distilled under reduced pressure to remove ethyl acetate, to obtain intermediate 1;

[0039] S2, in a three-necked flask equipped with a stirring device and a condensing device, 16.4 g of propylenediamine, 20.2 g of triethylamine, 80 mL of acetone and 80 mL of hexane were added, stirred to dissolve uniformly and the flask was placed in an ice water bath, the temperature of the system was controlled not to exceed 2 °C, then 29.4 g of 8-chloro-1-octene was slowly added dropwise, after the dropping was completed, the ice bath was removed and the reaction was carried out at room temperature for 2 h, after the reaction was completed, the generated salt was filtered off, the organic phase (liquid phase) was taken, washed with 20% NaCl aqueous solution for 5 times, dried with anhydrous Mg2SO4, filtered and finally distilled under reduced pressure to remove the solvent (hexane), to obtain intermediate 2;

[0040] S3, 36.8 g of intermediate 2, 80 mL of pyridine and 70 mL of ethyl ether were added into a three-necked flask equipped with a stirring device and a reflux condensing device, stirred to dissolve uniformly, then 24.4 g of 2-hydroxybenzaldehyde was added into the system, the temperature was raised to 62 °C and the reaction was carried out for 5 h, after the reaction was completed, most of the solvent was removed by rotary evaporation, and column chromatography was used for purification (the eluent was cyclohexane / ethyl acetate, and the volume ratio of the two was 1:1), the eluent was rotary evaporated to obtain intermediate 3;

[0041] S4, remove the air in the four-necked flask with N2, then add 57.6 g of intermediate 3 and 200 mL of DMF, stir to mix uniformly, control the temperature in the flask at 35-40°C, slowly drop 27.6 g of intermediate 1, 18.2 g of triethylamine and 50 mL of DMF into the mixture under stirring, continue to react at 40°C for 4 h after the dropping is completed, naturally cool to room temperature after the reaction is completed, add a large amount of deionized water, precipitate the organic matter, and finally dry the obtained organic matter to obtain the additive.

[0042] Example 3

[0043] Preparation of modified polypropylene material:

[0044] (1) Put 1 kg of polypropylene resin, 300 g of maleic anhydride grafted polypropylene, 250 g of nano calcium carbonate, 100 g of the additive prepared in Example 1, 20 g of silane coupling agent KH304 and 3 g of benzoyl peroxide into a high-speed mixer and mix until the generated friction heat of the mixing raises the temperature of the materials to 90°C, and then discharge and cool;

[0045] (2) Send the cooled mixed materials into a double-screw extruder for melt extrusion, cool the extruded strip in a water tank, pull into a granulator, and granulate to prepare the modified polypropylene material.

[0046] Example 4

[0047] Preparation of modified polypropylene material:

[0048] (1) Put 1 kg of polypropylene resin, 350 g of maleic anhydride grafted polypropylene, 300 g of nano calcium carbonate, 120 g of the additive prepared in Example 2, 25 g of silane coupling agent KH303 and 3.5 g of benzoyl peroxide into a high-speed mixer and mix until the generated friction heat of the mixing raises the temperature of the materials to 95°C, and then discharge and cool;

[0049] (2) Send the cooled mixed materials into a double-screw extruder for melt extrusion, cool the extruded strip in a water tank, pull into a granulator, and granulate to prepare the modified polypropylene material.

[0050] Example 5

[0051] Preparation of modified polypropylene material:

[0052] (1) Put 1 kg of polypropylene resin, 400 g of maleic anhydride grafted polypropylene, 350 g of nano calcium carbonate, 140 g of the additive prepared in Example 1, 30 g of silane coupling agent KH304 and 4 g of benzoyl peroxide into a high-speed mixer and mix until the generated friction heat of the mixing raises the temperature of the materials to 100°C, and then discharge and cool;

[0053] (2) the cooled mixture is fed into a twin-screw extruder for melt extrusion, the extruded strip is cooled in a water tank, drawn into a granulator for granulation, and the modified polypropylene material is prepared.

[0054] Comparative Example 1

[0055] The additive in Example 3 is replaced with the same mass of nitrogen-phosphorus flame retardant (HF-900A halogen-free flame retardant produced by Concorde), and the remaining raw materials and preparation process are unchanged, and the obtained polypropylene material is obtained.

[0056] Comparative Example 2

[0057] The additive raw material in Example 3 is removed, and the remaining raw materials and preparation process are unchanged, and the obtained polypropylene material is obtained.

[0058] The polypropylene materials obtained in Examples 3-5 and Comparative Examples 1-2 are processed and cut into test samples, and the following performance tests are carried out:

[0059] Mechanical properties: the tensile strength and elongation at break of the material are tested according to GB / T 1040.2-2006, and the rate is 50 mm / min;

[0060] Flame retardant performance: the oxygen index test of the material is carried out according to GB / T 2406.2-2009;

[0061] UV aging test: the material is subjected to 200h UV aging test according to GB / T 16422.2-2014;

[0062] The measured results are shown in the following table:

[0063]

[0064] From the above table data, it can be seen that the modified polypropylene material obtained by the application has high mechanical strength, meets the requirements of toughness, and has good flame retardance and aging resistance; combined with the data of Comparative Example 1 and Comparative Example 2, it can be seen that the additive in the application not only can effectively improve the flame retardant performance and aging resistance of the polypropylene material, but also can promote the formation of crosslinked network structure, thereby improving the mechanical strength of the material.

[0065] In the description of the specification, the description of the reference terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0066] The above merely illustrates and describes the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or adopt similar ways to replace, as long as the modifications or supplements do not deviate from the present application or exceed the scope defined by the present application, and should belong to the protection scope of the present application.

Claims

1. A modified polypropylene material, characterized in that, The raw materials include, by weight, polypropylene resin 100 parts, maleic anhydride grafted polypropylene 30-40 parts, nano calcium carbonate 25-35 parts, additives 10-14 parts, silane coupling agent 2-3 parts, and benzoyl peroxide 0.3-0.4 parts; The additives are prepared by the following steps: S1, after continuously introducing nitrogen into a three-necked flask for 10 min, hexachlorocyclotriphosphazene, dioxane and N,N-dimethylaniline are added, stirred and dissolved uniformly, then 2-chloro-1,3-propanediol dioxane solution is added dropwise, the reaction temperature is controlled to be not higher than 40℃ during the dropwise addition, the temperature is then increased to 100℃, and the reaction is kept for 15 h, then the temperature is decreased to below 30℃, and post-treatment is performed to obtain intermediate 1; S2, propylenediamine, triethylamine, acetone and hexane are added into a three-necked flask, stirred and dissolved uniformly, and the flask is placed in an ice water bath to control the temperature of the system to be not higher than 2℃, then 8-chloro-1-octene is slowly added dropwise, the ice bath is removed after the dropwise addition is completed, and the reaction is kept at room temperature for 2 h to obtain intermediate 2; S3, intermediate 2, pyridine and ether are added into a three-necked flask, stirred and dissolved uniformly, then 2-hydroxybenzaldehyde is added into the system, the temperature is increased to 62℃, and the reaction is kept for 5 h to obtain intermediate 3; S4, N2 is used to remove air in a four-necked flask, then intermediate 3 and DMF are added, stirred and mixed uniformly, the temperature in the flask is controlled to be 35-40℃, a mixture of intermediate 1, triethylamine and DMF is slowly added dropwise under stirring, the reaction is kept at 40℃ for 4 h after the dropwise addition is completed to obtain the additives; In step S1, the amount ratio of hexachlorocyclotriphosphazene, N,N-dimethylaniline and 2-chloro-1,3-propanediol is 10.4 g:21.8 g:11.1 g; in step S2, the amount ratio of propylenediamine, triethylamine and 8-chloro-1-octene is 8.2 g:10.1 g:14.7 g; in step S3, the amount ratio of intermediate 2 and 2-hydroxybenzaldehyde is 18.4 g:12.2 g; in step S4, the amount ratio of intermediate 3, intermediate 1 and triethylamine is 28.8 g:13.8 g:9.1 g.

2. The modified polypropylene material according to claim 1, characterized in that, The silane coupling agent is silane coupling agent KH304 or silane coupling agent KH303.

3. The method for preparing a modified polypropylene material according to claim 1, characterized in that, The following steps are included: (1) the raw materials are poured into a high-speed mixer according to the proportion, mixed until the friction heat generated by the mixing increases the temperature of the materials to 90-100℃, and the materials are discharged and cooled; (2) the cooled mixed materials are sent into a twin-screw extruder for melt extrusion, the extruded strip is cooled in a water tank, drawn into a granulator, and granulated to obtain the modified polypropylene material.

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