CN113001808A

CN113001808A - Preparation process of degradable polypropylene plastic

Info

Publication number: CN113001808A
Application number: CN202110187331.0A
Authority: CN
Inventors: 董丹丹
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-02-18
Filing date: 2021-02-18
Publication date: 2021-06-22

Abstract

The invention discloses a preparation process of degradable polypropylene plastic, which has the technical scheme key points that: the method comprises the following steps: step one, preparing raw materials: preparing the following components by weight: 20-60 parts of polypropylene, 4-8 parts of corn starch, 2-4 parts of a photosensitizer, 5-20 parts of an inorganic filler, 2-5 parts of a lubricant, 0.5-1.5 parts of a dispersant, 0.5-3 parts of an anti-aging agent, 2-8 parts of plant fiber, 0.9-1.2 parts of a coloring agent, 4-16 parts of an impact modifier, 1-3 parts of a cross-linking agent and 0.3-0.8 part of a coupling agent; step two, preliminary mixing: sequentially injecting polypropylene, corn starch, inorganic filler and plant fiber into a reaction kettle for mixing, controlling the temperature at 75-85 ℃, continuously preserving heat for reaction for 1-2h, controlling the stirring speed at 200-245r/min, and fully reacting to obtain a mixture A; the effects of high degradation speed and environmental protection are achieved.

Description

Preparation process of degradable polypropylene plastic

Technical Field

The invention belongs to the field of polypropylene plastic production, and particularly relates to a preparation process of degradable polypropylene plastic.

Background

The degradable plastic is a plastic which is added with a certain amount of additives (such as starch, modified starch or other celluloses, photosensitizers, biodegradable agents and the like) in the production process to reduce the stability of the degradable plastic and is then easily degraded in the natural environment, and tests show that most of degradable plastics begin to thin, lose weight and reduce strength after being exposed for 3 months in the general environment and gradually crack into fragments. If the fragments are buried in garbage or soil, the degradation effect is insignificant.

Reference can be made to chinese patent publication No. CN107984717A, which relates to a preparation process of antibacterial polypropylene plastic, comprising the following steps: s1, pretreating raw materials; s2 preheating treatment: preheating the injection molding barrel; installing an injection mold, and preheating an upper mold and a lower mold; s3 hot melting stage: s31: adding the pretreated substance into an injection molding cylinder, and heating to be molten; s32: after melting in the step S31, dropwise adding a mixed solution of an antibacterial agent and an auxiliary agent; s33: melting again for 15-30min after the dropwise adding in the step S32 to obtain the hot-melt plastic; s4 injection molding stage: injecting the hot melt plastic in the step S33 into the upper die and the lower die preheated in the step S3, and maintaining the pressure for 5-8S; s5 cooling and forming: and (4) placing the plastic plate subjected to pressure maintaining in the step S4 into a cooling water tank for cooling, and opening a mold to obtain the plastic plate.

The patent has the advantages of good bacteriostatic effect, good dispersibility, high forming rate and simple process, but also has the defects, such as: the degradation is poor, the environment is easily polluted after the use, and the environment is not protected.

Disclosure of Invention

The invention aims to provide a preparation process of degradable polypropylene plastic, which aims to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

a preparation process of degradable polypropylene plastic comprises the following steps:

step one, preparing raw materials: preparing the following components by weight: 20-60 parts of polypropylene, 4-8 parts of corn starch, 2-4 parts of a photosensitizer, 5-20 parts of an inorganic filler, 2-5 parts of a lubricant, 0.5-1.5 parts of a dispersant, 0.5-3 parts of an anti-aging agent, 2-8 parts of plant fiber, 0.9-1.2 parts of a coloring agent, 4-16 parts of an impact modifier, 1-3 parts of a cross-linking agent and 0.3-0.8 part of a coupling agent;

step two, preliminary mixing: sequentially injecting polypropylene, corn starch, inorganic filler and plant fiber into a reaction kettle for mixing, controlling the temperature at 75-85 ℃, continuously preserving heat for reaction for 1-2h, controlling the stirring speed at 200-245r/min, and fully reacting to obtain a mixture A;

step three, secondary mixing: sequentially injecting a photosensitizer, a lubricant, a dispersing agent, an anti-aging agent, a coloring agent, an impact modifier, a crosslinking agent and a coupling agent into a reaction kettle, and fully mixing with the mixture A prepared in the step two, controlling the stirring speed of the reaction kettle at 85-150r/min, controlling the reaction temperature at 100 ℃, and continuously preserving heat for 2-3 hours to obtain a mixture;

step four, spirally extruding materials: and (3) injecting the mixture obtained in the step three into a double-rod screw extruder by using conveying equipment, cooling the extruded strip material by a water tank and cooling the extruded strip material by air, conveying the cooled extruded strip material to a grain cutting equipment, and cutting the extruded strip material into grains by using grain cutting equipment to obtain the degradable polypropylene plastic particles.

Preferably, in the fourth step, the head temperature of the double-rod screw extruder is controlled to be 190-.

Preferably, after the four-screw extrusion, the quality of the prepared degradable polypropylene plastic particles is detected, if the detected quality is qualified, large-scale production is carried out, and if the detected quality is unqualified, technical improvement is carried out until the quality is qualified.

Preferably, the prepared degradable polypropylene plastic particles are transported to an injection molding device after the material is extruded spirally in the step four, the degradable polypropylene plastic particles are transported into the injection molding device by using a material transporting device, pressure is maintained for 5-8s after injection molding is completed, the injection molded degradable polypropylene plastic plate is placed into a cooling water tank for cooling after pressure maintaining, and the degradable polypropylene plastic plate is obtained after cooling is completed.

Preferably, the preparation process of the corn starch comprises the following steps:

s1, selecting mature high-quality current-season corn without diseases and insect pests, threshing by using threshing equipment, cleaning the obtained corn kernels by using cleaning equipment, and drying in the air after cleaning;

s2, drying the corn kernels aired in the S1 by using a dryer, and after drying is finished, finely grinding by using grinding equipment to obtain corn flour;

s3, putting the corn flour obtained in the S2 into a steamer for steaming and softening;

s4, placing the corn flour steamed and softened in the S3 into a reaction kettle for stirring, moving the mixture into pulping equipment after fully stirring, and adding distilled water to prepare corn flour serous fluid with the water content of 30-50%;

and S5, adding pectinase and cellulase into the corn flour slurry obtained in the step S3 for enzymolysis for 10min, carrying out homogenization treatment after the enzymolysis is finished, removing materials which are not subjected to enzymolysis treatment, adding high-efficiency liquefied pectinase, and carrying out spraying and drying to obtain the corn starch.

Preferably, in S1, after the cleaning with the cleaning agent is repeated three times, the cleaning is repeated five times until the corn kernels are clean and free of impurities.

Preferably, the temperature of the dryer is controlled to be 110 ℃ in S2. And continuously drying for 3h, controlling the rotating speed of the grinding equipment to be 200r/min, continuously grinding for 20min, controlling the rotating speed of the reaction kettle to be 220r/min in S4, and controlling the temperature of the reaction kettle to be 80 ℃.

Preferably, the preparation process of the plant fiber is as follows:

SS1, preparing reed leaves, cleaning, fully crushing by using crushing equipment, placing crushed reeds in drying equipment, and pre-drying for 8min at the set temperature of 60 ℃ to obtain a fiber primary material;

SS2, putting the fiber primary material obtained in the SS1 into a reaction kettle, then injecting 0.8g/L sulfuric acid solution into the reaction kettle to immerse the sulfuric acid solution into the fiber for discharging, then heating to 70-105 ℃, taking out the fiber primary material after lasting for 2-4h, washing with water to obtain a raw material A;

SS3, injecting alkali liquor into the raw material A obtained in the SS2, controlling the temperature of the reaction kettle at 100 ℃ and the pressure at 1MPa, taking out the reaction kettle after 1.5h, and washing the reaction kettle with hot water at 65 ℃;

and SS4, soaking the alkali-boiled raw material A into the emulsion, controlling the temperature to be 85 ℃, taking out after 5min, and then dehydrating, drying and carding to obtain the plant fiber.

Preferably, the alkali liquor in the SS3 comprises 10% NaOH aqueous solution, H2O2, water glass and OP-10.

Preferably, the emulsion in SS4 comprises a tetradecyldimethylbenzylammonium chloride solution and a benzalkonium chloride solution.

Compared with the prior art, the invention has the beneficial effects that:

when the preparation process of the degradable polypropylene plastic is used, the polypropylene is used as a base material, the inorganic filler is blended, the plant fiber and the photosensitizer are added, the raw materials are green and environment-friendly, and can be rapidly degraded, so that the degradable polypropylene plastic can be rapidly dispersed in an external environment and can be more rapidly in contact reaction with the external physical and chemical environment, the degradation speed is improved, a dual degradation mode of photodecomposition and biodegradation can be achieved through the addition of the plant fiber and the photosensitizer, the degradation speed is greatly improved, and the effects of rapid degradation and environmental protection are achieved.

When the preparation process of the degradable polypropylene plastic is used, the properties of the polypropylene such as stability, formability, mechanical property, antibacterial property, aging resistance and the like are improved through the mutual matching and combined action of the lubricant, the dispersant, the anti-aging agent, the impact modifier, the cross-linking agent and the coupling agent, and the preparation process has good yellowing resistance, can reduce the harm to the environment, improves the crystallinity and the crystallization rate of the polypropylene, improves the size and the arrangement of a crystal phase, further obviously improves the heat resistance and the toughness of the polypropylene, and can be suitable for most plastic products.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of a corn starch process of the present invention;

FIG. 3 is a block diagram of the plant fiber process of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious 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.

Example 1

step one, preparing raw materials: preparing the following components by weight: 40 parts of polypropylene, 8 parts of corn starch, 3 parts of photosensitizer, 8 parts of inorganic filler, 3 parts of lubricant, 0.5 part of dispersant, 0.5 part of anti-aging agent, 3 parts of plant fiber, 0.9 part of colorant, 4 parts of impact modifier, 1 part of crosslinking agent and 0.3 part of coupling agent;

step two, preliminary mixing: sequentially injecting polypropylene, corn starch, inorganic filler and plant fiber into a reaction kettle for mixing, controlling the temperature at 75 ℃, keeping the temperature for reaction for 2 hours, controlling the stirring speed at 200r/min, and obtaining a mixture A after the reaction is fully performed;

step three, secondary mixing: sequentially injecting a photosensitizer, a lubricant, a dispersing agent, an anti-aging agent, a coloring agent, an impact modifier, a crosslinking agent and a coupling agent into a reaction kettle, and fully mixing with the mixture A prepared in the step two, controlling the stirring speed of the reaction kettle at 150r/min, controlling the reaction temperature at 100 ℃, and continuously preserving heat for 2 hours to obtain a mixture;

In this embodiment, preferably, in the fourth step, the head temperature of the double-screw extruder is controlled to be 190 ℃, the rotation speed of the screw of the main machine of the double-screw extruder is controlled to be 200rpm, the rotation speed of the feeding rod of the double-screw extruder is controlled to be 20rpm, the main body of the double-screw extruder includes a front section, an interruption section and a rear section, the temperature of the front section is controlled to be 150 ℃, the temperature of the interruption section is controlled to be 170 ℃, and the temperature of the rear section is controlled to be 190 ℃.

In this embodiment, preferably, after the four-screw extrusion, the quality of the prepared degradable polypropylene plastic granules is detected, and if the detected quality is qualified, the mass production is performed, and if the detected quality is not qualified, the technical improvement is performed until the quality is qualified.

In this embodiment, preferably, after the four-step screw extrusion, the prepared degradable polypropylene plastic particles are transported to an injection molding device, the degradable polypropylene plastic particles are transported into the injection molding device by using a material transporting device, pressure is maintained for 8s after the injection molding is completed, the injection molded degradable polypropylene plastic plate is placed into a cooling water tank for cooling after the pressure is maintained, and the degradable polypropylene plastic plate is obtained after the cooling is completed.

In this embodiment, preferably, the preparation process of the corn starch is as follows:

s4, placing the corn flour steamed and softened in the step S3 into a reaction kettle for stirring, moving the mixture into pulping equipment after the mixture is fully stirred, and adding distilled water to prepare corn flour slurry with the water content of 50%;

In this embodiment, preferably, the cleaning agent is used to repeatedly clean three times in S1, and then the cleaning agent is used to repeatedly clean five times until the corn kernels are clean and free of impurities.

In this embodiment, it is preferable that the temperature of the dryer is controlled to 110 ℃ in S2. And (3) continuously drying for 3h, controlling the rotating speed of the grinding equipment to be 200r/min, continuously grinding for 20min, controlling the rotating speed of the reaction kettle to be 220r/min in S4, and controlling the temperature of the reaction kettle to be 80 ℃.

In this embodiment, preferably, the preparation process of the plant fiber is as follows:

SS2, putting the fiber primary material obtained in the SS1 into a reaction kettle, then injecting a 0.8g/L sulfuric acid solution into the reaction kettle to immerse the sulfuric acid solution into the fiber for discharging, then heating to 105 ℃, taking out the fiber primary material after lasting for 4 hours, washing with water to obtain a raw material A;

In this embodiment, the alkali solution in SS3 preferably comprises 10% NaOH aqueous solution, H2O2, water glass and OP-10.

In this embodiment, the emulsion in SS4 preferably includes a tetradecyldimethylbenzylammonium chloride solution and a benzalkonium chloride solution.

The invention has the beneficial effects that:

Example 2

step one, preparing raw materials: preparing the following components by weight: 60 parts of polypropylene, 4 parts of corn starch, 2 parts of photosensitizer, 20 parts of inorganic filler, 5 parts of lubricant, 1.5 parts of dispersant, 3 parts of anti-aging agent, 2 parts of plant fiber, 0.9 part of colorant, 4 parts of impact modifier, 1 part of crosslinking agent and 0.3 part of coupling agent;

step two, preliminary mixing: sequentially injecting polypropylene, corn starch, inorganic filler and plant fiber into a reaction kettle for mixing, controlling the temperature at 75 ℃, keeping the temperature for reaction for 1h, controlling the stirring speed at 200r/min, and obtaining a mixture A after the reaction is fully performed;

step three, secondary mixing: sequentially injecting a photosensitizer, a lubricant, a dispersing agent, an anti-aging agent, a coloring agent, an impact modifier, a crosslinking agent and a coupling agent into a reaction kettle, and fully mixing with the mixture A prepared in the step two, controlling the stirring speed of the reaction kettle at 85r/min, controlling the reaction temperature at 100 ℃, and continuously preserving heat for 2 hours to obtain a mixture;

In this embodiment, preferably, in the fourth step, the head temperature of the double-screw extruder is controlled to be 190 ℃, the rotation speed of the screw of the main machine of the double-screw extruder is controlled to be 300rpm, the rotation speed of the feeding rod of the double-screw extruder is controlled to be 40rpm, the main body of the double-screw extruder comprises a front section, an interruption section and a rear section, the temperature of the front section is controlled to be 150 ℃, the temperature of the interruption section is controlled to be 170 ℃, and the temperature of the rear section is controlled to be 190 ℃.

In this embodiment, preferably, after the four-step screw extrusion, the prepared degradable polypropylene plastic particles are transported to an injection molding device, the degradable polypropylene plastic particles are transported into the injection molding device by using a material transporting device, pressure is maintained for 5 seconds after the injection molding is completed, the injection molded degradable polypropylene plastic plate is placed into a cooling water tank for cooling after the pressure is maintained, and the degradable polypropylene plastic plate is obtained after the cooling is completed.

s4, placing the corn flour steamed and softened in the step S3 into a reaction kettle for stirring, moving the mixture into pulping equipment after the mixture is fully stirred, and adding distilled water to prepare corn flour slurry with the water content of 30%;

The invention has the beneficial effects that:

Example 3

step one, preparing raw materials: preparing the following components by weight: 30 parts of polypropylene, 8 parts of corn starch, 3 parts of photosensitizer, 13 parts of inorganic filler, 3 parts of lubricant, 0.5 part of dispersant, 0.5 part of anti-aging agent, 2 parts of plant fiber, 0.9 part of colorant, 16 parts of impact modifier, 3 parts of crosslinking agent and 0.3 part of coupling agent;

step two, preliminary mixing: sequentially injecting polypropylene, corn starch, inorganic filler and plant fiber into a reaction kettle for mixing, controlling the temperature at 85 ℃, keeping the temperature for reaction for 2 hours, controlling the stirring speed at 245r/min, and obtaining a mixture A after the reaction is fully performed;

step three, secondary mixing: sequentially injecting a photosensitizer, a lubricant, a dispersing agent, an anti-aging agent, a coloring agent, an impact modifier, a crosslinking agent and a coupling agent into a reaction kettle, and fully mixing with the mixture A prepared in the step two, controlling the stirring speed of the reaction kettle at 150r/min, controlling the reaction temperature at 100 ℃, and continuously preserving heat for 3 hours to obtain a mixture;

In this embodiment, preferably, in the fourth step, the head temperature of the dual-screw extruder is controlled to be 210 ℃, the rotation speed of the screw of the main machine of the dual-screw extruder is controlled to be 300rpm, the rotation speed of the feeding rod of the dual-screw extruder is controlled to be 40rpm, the main body of the dual-screw extruder includes a front section, an interruption section and a rear section, the temperature of the front section is controlled to be 150 ℃, the temperature of the interruption section is controlled to be 170 ℃, and the temperature of the rear section is controlled to be 190 ℃.

SS2, putting the fiber primary material obtained in the SS1 into a reaction kettle, then injecting 0.8g/L sulfuric acid solution into the reaction kettle to immerse the sulfuric acid solution into the fiber for discharging, then heating to 70 ℃, taking out the fiber primary material after lasting for 4 hours, washing with water to obtain a raw material A;

The invention has the beneficial effects that:

The tensile strength and elongation at break were measured at a test speed of 10mm/min for the degradable polypropylene plastics prepared in examples one to three and the comparative example plastics according to the method described in GB/T1040-1992 "test methods for tensile Properties of plastics", and the results are shown in Table 1; according to GB/T1634.1-2004 part 1 of the determination of the deformation temperature under load of plastics: the heat distortion temperatures of the degradable polypropylene plastics prepared in examples one to three and the comparative example plastic were measured by the method described in general test methods ″, and the results obtained are shown in table 1:

	tensile strength/MPa	Elongation at break/%	Heat distortion temperature/° C
				Example 1	65	48	145
Example 2	62	47	143
				Example 3	61	43	144
Comparative example	58	45	123

TABLE 1

As can be seen from the table I, the degradable polypropylene plastic prepared in example 1 has the best data, so example 1 is the optimal preparation process.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The preparation process of the degradable polypropylene plastic is characterized by comprising the following steps of:

2. The preparation process of the degradable polypropylene plastic according to claim 1, wherein the preparation process comprises the following steps: in the fourth step, the head temperature of the double-rod screw extruder is controlled to be 190-210 ℃, the rotating speed of a main machine screw of the double-rod screw extruder is controlled to be 200-300rpm, the rotating speed of a feeding rod of the double-rod screw extruder is controlled to be 20-40rpm, the main body of the double-rod screw extruder comprises a front section, an interruption section and a rear section, the temperature of the front section is controlled to be 150 ℃, the temperature of the interruption section is controlled to be 170 ℃, and the temperature of the rear section is controlled to be 190 ℃.

3. The preparation process of the degradable polypropylene plastic according to claim 1, wherein the preparation process comprises the following steps: after the material is extruded spirally in the step four, the quality of the prepared degradable polypropylene plastic particles is detected, if the detected quality is qualified, large-scale production is carried out, and if the detected quality is unqualified, technical improvement is carried out until the quality is qualified.

4. The preparation process of the degradable polypropylene plastic according to claim 1, wherein the preparation process comprises the following steps: transporting the prepared degradable polypropylene plastic particles to an injection molding device after the four-screw extrusion, transporting the degradable polypropylene plastic particles into the injection molding device by using a material conveying device, maintaining the pressure for 5-8s after the injection molding is finished, cooling the injection molded degradable polypropylene plastic plate in a cooling water tank after the pressure maintaining, and obtaining the degradable polypropylene plastic plate after the cooling is finished.

5. The preparation process of the degradable polypropylene plastic according to claim 1, wherein the preparation process comprises the following steps: the preparation process of the corn starch comprises the following steps:

6. The preparation process of the degradable polypropylene plastic according to claim 5, wherein the preparation process comprises the following steps: and in the step S1, repeatedly cleaning the corn kernels for three times by using a cleaning agent, and then repeatedly cleaning the corn kernels for five times until the corn kernels are clean and free of impurities.

7. The preparation process of the degradable polypropylene plastic according to claim 5, wherein the preparation process comprises the following steps: controlling the temperature of the dryer to be 110 ℃ in the S2; and continuously drying for 3h, controlling the rotating speed of the grinding equipment to be 200r/min, continuously grinding for 20min, controlling the rotating speed of the reaction kettle to be 220r/min in S4, and controlling the temperature of the reaction kettle to be 80 ℃.

8. The preparation process of the degradable polypropylene plastic according to claim 1, wherein the preparation process comprises the following steps: the preparation process of the plant fiber comprises the following steps:

9. The preparation process of the degradable polypropylene plastic according to claim 8, wherein the preparation process comprises the following steps: the alkali liquor in the SS3H is prepared by fully mixing 10% NaOH aqueous solution, H2O2, water glass and OP-10.

10. The preparation process of the degradable polypropylene plastic according to claim 8, wherein the preparation process comprises the following steps: the emulsion in the SS4 comprises a tetradecyldimethylbenzylammonium chloride solution and a benzalkonium chloride solution.