阅读说明：本技术 一种聚丙烯塑料粒子的制备方法 (Preparation method of polypropylene plastic particles ) 是由 马健珂 丁贤麟 刘永利 于 2020-06-11 设计创作，主要内容包括：本发明公开了一种聚丙烯塑料粒子的制备方法,该聚丙烯塑料粒子由如下重量份的原料制成：改性聚丙烯100-120份、滑石粉16-20份、阻燃剂10-15份、抑菌剂3-5份、硬脂酸钙2-3份、分散剂4-8份；制备方法如下：按配方量将改各物质混合均匀后经熔融共混、挤出、造粒。本发明通过采用改性聚丙烯作为塑料基体,不仅具有更高的抗冲性能,而且还接枝了-COOH官能团,能够增加基体与阻燃剂、抑菌剂的相容性和结合力,使阻燃剂、抑菌剂等均匀分散于基体中,赋予聚丙烯粒子良好的阻燃和抑菌性能；通过特定粒径的滑石粉和硬质酸钙的辅配,不仅能够提高PP的刚性,也能够提高聚丙烯的韧性,得到力学性能优异、并具有阻燃和抑菌功能的聚丙烯塑料。(The invention discloses a preparation method of polypropylene plastic particles, which are prepared from the following raw materials in parts by weight: 100-120 parts of modified polypropylene, 16-20 parts of talcum powder, 10-15 parts of flame retardant, 3-5 parts of bacteriostatic agent, 2-3 parts of calcium stearate and 4-8 parts of dispersing agent; the preparation method comprises the following steps: the materials are evenly mixed according to the formula amount, and then are melted, blended, extruded and granulated. According to the invention, the modified polypropylene is adopted as the plastic substrate, so that the modified polypropylene has higher impact resistance, and-COOH functional groups are grafted, so that the compatibility and the binding force of the substrate with a flame retardant and a bacteriostatic agent can be increased, the flame retardant, the bacteriostatic agent and the like are uniformly dispersed in the substrate, and the polypropylene particles are endowed with good flame retardance and bacteriostatic performance; by the aid of the talcum powder with the specific particle size and the calcium stearate, the rigidity of PP (polypropylene) can be improved, the toughness of the polypropylene can be improved, and the polypropylene plastic with excellent mechanical property and flame-retardant and antibacterial functions is obtained.)

1. The preparation method of the polypropylene plastic particles is characterized in that the polypropylene plastic particles are prepared from the following raw materials in parts by weight: 100-120 parts of modified polypropylene, 16-20 parts of talcum powder, 10-15 parts of flame retardant, 3-5 parts of bacteriostatic agent, 2-3 parts of calcium stearate and 4-8 parts of dispersing agent;

the preparation method of the polypropylene plastic particle comprises the following steps:

s1, mixing the modified polypropylene, the talcum powder, the calcium stearate and the dispersing agent according to the formula amount, stirring for 9-12min at the speed of 130r/min for 120-;

s2, adding a flame retardant and a bacteriostatic agent into the mixture, stirring and mixing for 4-5min at 300r/min, and then increasing the rotating speed to 1000-1200r/min and stirring for 2-3min to obtain a blend;

and S3, putting the blend into a double-screw extruder, and carrying out melt blending, extrusion and granulation to obtain the polypropylene plastic particles.

2. The method for preparing polypropylene plastic particles according to claim 1, wherein the particle size of the talcum powder is 4-5 um.

3. The method for preparing polypropylene plastic particles according to claim 1, wherein the flame retardant is prepared by the following steps:

dissolving p-hydroxyaniline and triethylamine in acetonitrile, introducing nitrogen for 10-15min, controlling the temperature of a mixed solution at 3-5 ℃, slowly dripping acetonitrile solution of phosphorus oxychloride into the mixed solution, keeping an ice bath reaction for 60-70min after finishing dripping, moving the whole device into an oil bath kettle at 48-50 ℃, carrying out reflux reaction for 22-24h under nitrogen, and after the reaction is finished, carrying out suction filtration, washing and drying on a product to obtain the flame retardant.

4. The method for preparing polypropylene plastic particles according to claim 3, wherein the concentration of the phosphoryl chloride-acetonitrile solution is 0.25 mol/L; the mass ratio of p-hydroxyaniline, triethylamine and phosphorus oxychloride was 3.2:5: 1.

5. The method for preparing polypropylene plastic particles according to claim 1, wherein the modified polypropylene is prepared by the following steps:

weighing a certain amount of polypropylene resin, weighing a certain amount of sorbic acid and dibenzoyl peroxide according to a proportion, putting the mixture into a high-pressure reaction kettle, vacuumizing, introducing carbon dioxide until the pressure is 14MPa, putting the mixture into a constant-temperature water tank for reaction for 7-8h at 70-72 ℃, taking out and cooling to obtain the modified polypropylene.

6. The method for preparing polypropylene plastic particles according to claim 5, wherein the mass ratio of the polypropylene resin to the sorbic acid to the benzoyl peroxide is 25:5: 1.

7. The method for preparing polypropylene plastic particles according to claim 1, wherein the bacteriostatic agent is prepared by the following steps:

adding 0.5mL of AgNO into a beaker containing 49mL of ultrapure water under the conditions of ice bath and uniform stirring at 300r/min₃The solution and 0.5mL of ethylenediamine were added followed by the rapid addition of 0.3mL of 0.3mol/L NaBH₄Stirring the solution for 3min to change the color of the solution into brown yellow, dialyzing for 12h, and then drying in vacuum to obtain the bacteriostatic agent.

8. The method for preparing polypropylene plastic particles as claimed in claim 7, wherein the mass fraction of the silver nitrate solution is 1%.

Technical Field

The invention belongs to the field of polypropylene plastics, and particularly relates to a preparation method of polypropylene plastic particles.

Background

Polypropylene, PP for short, is a colorless, odorless, nontoxic and semitransparent solid substance. Polypropylene (PP) is a thermoplastic synthetic resin with excellent performance, and is colorless translucent thermoplastic light general-purpose plastic. The polypropylene has chemical resistance, heat resistance, electrical insulation, high-strength mechanical property, good high-wear-resistance processing property and the like, so that the polypropylene can be rapidly and widely developed and applied in a plurality of fields such as machinery, automobiles, electronic and electric appliances, buildings, textiles, packaging, agriculture, forestry, fishery, food industry and the like since the coming out. When the polypropylene plastic product is used for manufacturing children toys, the problems of poor flame retardance, poor heat resistance, no antibacterial performance, toxic plasticizer and the like of the plastic are solved, so that the quality of the toys is not influenced, and the health of the children is not harmed.

Chinese patent No. CN201611204158.6 discloses a method for preparing environment-friendly antibacterial polypropylene plastic particles, which comprises the steps of mixing polypropylene, a composite bacteriostatic agent, nano antibacterial particles, a plasticizer, diethyl malonate, polyphenylene sulfide, copper oxide and mineral oil according to a certain weight ratio, adding the mixture into a mixer, uniformly mixing and stirring, wherein the mixing temperature is 110-125 ℃, the mixing time is 20-30 minutes, after uniform mixing, transferring the mixture to a cooling mixer, stirring at a low speed for 10-12 minutes, and finally feeding the mixture into a double-screw extrusion granulator, plasticizing and granulating at 140 ℃ to obtain the environment-friendly antibacterial polypropylene plastic particles. The polypropylene plastic particles with antibacterial effect are obtained by melting and blending the composite bacteriostatic agent, the nano antibacterial particles and polypropylene. However, the composite bacteriostatic agent and the nano antibacterial particles are inorganic substances and have poor compatibility with a polypropylene matrix, so that the obtained polypropylene plastic particles are still deficient in performance.

Disclosure of Invention

The invention aims to provide a preparation method of polypropylene plastic particles, wherein modified polypropylene is adopted as a plastic substrate, and compared with PP, the modified polypropylene not only has higher impact resistance, but also is grafted with-COOH functional groups, so that the compatibility and the binding force of the substrate with a flame retardant and a bacteriostatic agent can be increased, the flame retardant, the bacteriostatic agent and the like are uniformly dispersed in the substrate, the flame retardant and the bacteriostatic performance are continuously and stably exerted, and the polypropylene particles are endowed with good flame retardant and bacteriostatic performance; through the auxiliary matching of the talcum powder with the specific particle size and the calcium stearate, the rigidity of PP can be improved, the toughness of the polypropylene can also be improved, the polypropylene plastic with excellent mechanical property and flame-retardant and antibacterial functions is obtained, and the application range of the polypropylene plastic can be greatly expanded.

The purpose of the invention can be realized by the following technical scheme:

a preparation method of polypropylene plastic particles comprises the following raw materials in parts by weight: 100-120 parts of modified polypropylene, 16-20 parts of talcum powder, 10-15 parts of flame retardant, 3-5 parts of bacteriostatic agent, 2-3 parts of calcium stearate and 4-8 parts of dispersing agent;

the preparation method of the polypropylene plastic particle comprises the following steps:

s1, mixing the modified polypropylene, the talcum powder, the calcium stearate and the dispersing agent according to the formula amount, stirring for 9-12min at the speed of 130r/min for 120-;

s2, adding a flame retardant and a bacteriostatic agent into the mixture, stirring and mixing for 4-5min at 300r/min, and then increasing the rotating speed to 1000-1200r/min and stirring for 2-3min to obtain a blend;

and S3, putting the blend into a double-screw extruder, and carrying out melt blending, extrusion and granulation to obtain the polypropylene plastic particles.

Furthermore, the particle size of the talcum powder is 4-5 um.

Further, the flame retardant is prepared by the following method:

dissolving p-hydroxyaniline and triethylamine in acetonitrile, introducing nitrogen for 10-15min, controlling the temperature of a mixed solution at 3-5 ℃, slowly dripping acetonitrile solution of phosphorus oxychloride into the mixed solution, keeping an ice bath reaction for 60-70min after finishing dripping, moving the whole device into an oil bath kettle at 48-50 ℃, carrying out reflux reaction for 22-24h under nitrogen, and after the reaction is finished, carrying out suction filtration, washing and drying on a product to obtain the flame retardant.

Further, the concentration of the phosphorus oxychloride-acetonitrile solution is 0.25 mol/L; the mass ratio of p-hydroxyaniline, triethylamine and phosphorus oxychloride was 3.2:5: 1.

Further, the modified polypropylene is prepared by the following method:

weighing a certain amount of polypropylene resin, weighing a certain amount of sorbic acid and dibenzoyl peroxide according to a proportion, putting the mixture into a high-pressure reaction kettle, vacuumizing, introducing carbon dioxide until the pressure is 14MPa, putting the mixture into a constant-temperature water tank for reaction for 7-8h at 70-72 ℃, taking out and cooling to obtain the modified polypropylene.

Further, the mass ratio of the polypropylene resin to the sorbic acid to the benzoyl peroxide is 25:5: 1.

Further, the bacteriostatic agent is prepared by the following method:

adding 0.5mL of AgNO into a beaker containing 49mL of ultrapure water under the conditions of ice bath and uniform stirring at 300r/min₃The solution and 0.5mL of ethylenediamine were added followed by the rapid addition of 0.3mL of 0.3mol/L NaBH₄Stirring the solution for 3min to change the color of the solution into brown yellow, dialyzing for 12h, and then drying in vacuum to obtain the bacteriostatic agent.

Further, the mass fraction of the silver nitrate solution is 1%.

The invention has the beneficial effects that:

the invention adopts modified polypropylene as a plastic matrix and uses modified polypropylene in CO₂Graft modification of PP in supercritical state, CO₂Has strong swelling capacity to PP resin in a supercritical state, can swell PP, dissolve an initiator and a monomer into the PP, and initiate free radical graft polymerization until the temperature is far lower than that suitable for initiating reactionThe swelling temperature of the temperature, the large diffusion coefficient and the zero surface tension of the supercritical fluid under higher pressure can also improve the grafting depth and the grafting uniformity while maintaining the excellent mechanical property of the PP; the sorbic acid molecule contains C ═ C double bond, and is added in initiator and supercritical CO₂Under the action of the catalyst, a free radical grafting reaction is carried out, so that sorbic acid is grafted on a polypropylene molecular chain; moreover, the sorbic acid molecule contains two C ═ C double bonds, and the other C ═ C double bond can be continuously grafted with polypropylene to form a bridge between polypropylene molecular chains, so that the polypropylene molecular chains form a cross-linked network system, the network structure is easy to deform under external force bearing, and the macroscopic expression is toughness enhancement, so that the toughening effect on PP is achieved; the obtained modified polypropylene contains-COOH, -COOH and phenolic hydroxyl on flame retardant molecules, so that the compatibility and the binding force of the flame retardant molecules and a PP matrix can be effectively improved, the flame retardant is uniformly and stably dispersed in the modified PP matrix, and the flame retardant performance is better exerted;

the invention adds the synthesized flame retardant into the modified polypropylene matrix, the flame retardant is synthesized by adopting p-hydroxyphenylamine and phosphoryl chloride, and the benzene ring of the p-hydroxyphenylamine is connected with para-amino-NH₂and-OH, NH when reacted with phosphorus oxychloride₂Carrying out substitution reaction with P-Cl to form an O ═ P-NH-bond, wherein the synthesized flame retardant contains a plurality of phenolic hydroxyl groups and can interact with a PP matrix; in addition, the synthesized flame retardant has O ═ P-NH-bond, namely contains P, N elements, and is a P-N type composite intumescent flame retardant; when the flame retardant is decomposed by heat, NH released by the flame retardant₃And H₂O, which can play a role of a gas source and simultaneously plays a role of diluting the concentration of combustible gas and oxygen to slow down the combustion speed; in addition, a benzene ring and a part of PP molecular chains generated after the flame retardant is decomposed can be used as a carbon source, phosphoric acid, metaphosphoric acid and the like generated by the decomposition of the flame retardant can be used as an acid source, and the carbon source and the acid source interact to generate an expanded compact and thick carbon residue layer which covers the surface of the PP material to isolate the transmission of oxygen and heat and play a role in flame retardance; the flame retardant is added to endow PP plastic with good flame retardant performance;

according to the invention, the modified polypropylene is adopted as the plastic substrate, and compared with PP, the modified polypropylene not only has higher impact resistance, but also is grafted with-COOH functional groups, so that the compatibility and the binding force of the substrate with a flame retardant and a bacteriostatic agent can be increased, the flame retardant, the bacteriostatic agent and the like are uniformly dispersed in the substrate, the flame retardant and the bacteriostatic performance are continuously and stably exerted, and the polypropylene particles are endowed with good flame retardant and bacteriostatic performance; through the auxiliary matching of the talcum powder with the specific particle size and the calcium stearate, the rigidity of PP can be improved, the toughness of the polypropylene can also be improved, the polypropylene plastic with excellent mechanical property and flame-retardant and antibacterial functions is obtained, and the application range of the polypropylene plastic can be greatly expanded.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A preparation method of polypropylene plastic particles comprises the following raw materials in parts by weight: 100-120 parts of modified polypropylene, 16-20 parts of talcum powder, 10-15 parts of flame retardant, 3-5 parts of bacteriostatic agent, 2-3 parts of calcium stearate and 4-8 parts of dispersing agent;

the dispersant is liquid paraffin;

the particle size of the talcum powder is 4-5 um; when the talcum powder and the PP are melted and blended, the talcum powder in the particle size range can not only enhance the rigidity of the PP, but also enhance the toughness of the PP, the enhancement of the rigidity of the PP is the enhancement of the inorganic filler, and the enhancement of the toughness of the PP has two reasons: on one hand, the particle size of the talcum powder is smaller, and the talcum powder particles are easy to move; on the other hand, the sheet structure of the talcum powder and the active points on the surface of the talcum powder are less, and gaps are easily generated between the resin and the talcum powder particles, which is reflected in the improvement of toughness; under the promoting action of calcium stearate and a dispersing agent, the dispersibility of the talcum powder can be improved;

the flame retardant is prepared by the following method:

dissolving p-hydroxyaniline and triethylamine in acetonitrile, introducing nitrogen for 10-15min, controlling the temperature of a mixed solution at 3-5 ℃, slowly dripping acetonitrile solution of phosphorus oxychloride (the concentration of the phosphorus oxychloride-acetonitrile solution is 0.25mol/L) into the mixed solution, keeping ice bath reaction for 60-70min after finishing dripping, moving the whole device into an oil bath kettle at 48-50 ℃, carrying out reflux reaction for 22-24h under nitrogen, and after the reaction is finished, carrying out suction filtration, washing and drying on a product to prepare the flame retardant;

the mass ratio of the p-hydroxyphenylamine, the triethylamine and the phosphorus oxychloride is 3.2:5: 1;

the benzene ring of the p-hydroxyaniline is connected with para-amino-NH₂and-OH, NH when reacted with phosphorus oxychloride₂Carrying out substitution reaction with P-Cl to form an O ═ P-NH-bond, wherein the synthesized flame retardant contains a plurality of phenolic hydroxyl groups and can interact with a PP matrix; in addition, the synthesized flame retardant has O ═ P-NH-bond, namely contains P, N elements, and is a P-N type composite intumescent flame retardant; when the flame retardant is decomposed by heat, NH released by the flame retardant₃And H₂O, which can play a role of a gas source and simultaneously plays a role of diluting the concentration of combustible gas and oxygen to slow down the combustion speed; in addition, a benzene ring and a part of PP molecular chains generated after the flame retardant is decomposed can be used as a carbon source, phosphoric acid, metaphosphoric acid and the like generated by the decomposition of the flame retardant can be used as an acid source, and the carbon source and the acid source interact to generate an expanded compact and thick carbon residue layer which covers the surface of the PP material to isolate the transmission of oxygen and heat and play a role in flame retardance; the flame retardant is added to endow PP plastic with good flame retardant performance;

the modified polypropylene is prepared by the following method:

weighing a certain amount of polypropylene resin, weighing a certain amount of sorbic acid and dibenzoyl peroxide (BPO) according to a certain proportion, putting the mixture into a high-pressure reaction kettle, vacuumizing, introducing carbon dioxide until the pressure is 14MPa, putting the mixture into a constant-temperature water tank for reaction, reacting for 7-8h at 70-72 ℃, taking out and cooling to obtain modified polypropylene;

wherein the mass ratio of the polypropylene resin to the sorbic acid to the benzoyl peroxide is 25:5: 1;

CO₂the high-performance graft copolymer has strong swelling capacity on PP resin in a supercritical state, can swell PP, dissolve an initiator and a monomer into the PP, and initiate free radical graft polymerization, and can improve the grafting depth and grafting uniformity when the excellent mechanical properties of the PP are kept at a swelling temperature far lower than a proper initiation reaction temperature and under high pressure due to the large diffusion coefficient and zero surface tension of a supercritical fluid; the sorbic acid molecule contains C ═ C double bond, and is added in initiator and supercritical CO₂Under the action of the catalyst, a free radical grafting reaction is carried out, so that sorbic acid is grafted on a polypropylene molecular chain; moreover, the sorbic acid molecule contains two C ═ C double bonds, and the other C ═ C double bond can be continuously grafted with polypropylene to form a bridge between polypropylene molecular chains, so that the polypropylene molecular chains form a cross-linked network system, the network structure is easy to deform under external force bearing, and the macroscopic expression is toughness enhancement, so that the toughening effect on PP is achieved; the obtained modified polypropylene contains-COOH, -COOH and phenolic hydroxyl on flame retardant molecules, so that the compatibility and the binding force of the flame retardant molecules and a PP matrix can be effectively improved, the flame retardant is uniformly and stably dispersed in the modified PP matrix, and the flame retardant performance is better exerted;

the bacteriostatic agent is prepared by the following method:

adding 0.5mL of AgNO into a beaker containing 49mL of ultrapure water under the conditions of ice bath and uniform stirring at 300r/min₃Solution (silver nitrate solution mass fraction of 1%) and 0.5mL of ethylenediamine, followed by the rapid addition of 0.3mL of 0.3mol/L NaBH₄Stirring the solution for 3min to change the color of the solution into brown yellow, dialyzing for 12h, and then performing vacuum drying to obtain the bacteriostatic agent;

the aminated nano-silver prepared by the in-situ modification method is easier to combine with bacteria due to positive charges on the surface, and can combine with cell membranes through the electrostatic sound absorption effect, so that the permeability of the cell membranes of the bacteria is improved, the growth of the bacteria is inhibited, and the antibacterial effect is more excellent than that of the nano-silver; moreover, the organic small molecules are combined on the AgNPs surface to prevent coagulation and are fused togetherMixed time-NH₂The modified polypropylene nano-silver particle can act with-COOH grafted on phenolic hydroxyl groups on the surface of the flame retardant or a modified polypropylene molecular chain, so that the compatibility and the binding force of the nano-silver particles with a matrix and other substances in the matrix are improved, the dispersion uniformity and the adhesion firmness of the nano-silver are further improved, and the antibacterial effect is continuously and stably exerted;

the preparation method of the polypropylene plastic particle comprises the following steps:

s1, mixing the modified polypropylene, the talcum powder, the calcium stearate and the dispersing agent according to the formula amount, stirring for 9-12min at the speed of 130r/min for 120-;

s2, adding a flame retardant and a bacteriostatic agent into the mixture, stirring and mixing for 4-5min at 300r/min, and then increasing the rotating speed to 1000-1200r/min and stirring for 2-3min to obtain a blend;

and S3, putting the blend into a double-screw extruder, and carrying out melt blending, extrusion and granulation to obtain the polypropylene plastic particles.