CN115838507B - High-strength degradable polyethylene casting film and preparation method thereof - Google Patents

Abstract

The application relates to the field of polyethylene plastic casting film processing, and particularly discloses a high-strength degradable polyethylene casting film and a preparation method thereof. The casting film comprises the following components in parts by weight: 290-300 parts of matrix resin, 210-220 parts of calcium carbonate, 35-45 parts of starch, 5-11 parts of defoamer, 3-5 parts of pigment master batch, 0.1-0.3 part of opening agent, 4.2-4.6 parts of coupling agent, 78-87 parts of plasticizer, 8.7-9.0 parts of modified sepiolite powder, 5.6-6.6 parts of eggshell powder, 8.7-9.3 parts of triglycerin monostearate and 14-15 parts of interfacial compatilizer; the preparation method comprises the following steps: s1, mixing all raw materials; s2, extruding and granulating the mixture, drying, casting, stretching and shaping. The polyethylene casting film is degradable, environment-friendly, less in environmental pollution, and high in strength and antibacterial performance while guaranteeing ductility.

Description

High-strength degradable polyethylene casting film and preparation method thereof

Technical Field

The present application relates to the field of polyethylene plastic cast film processing, and more particularly, to a high strength degradable polyethylene cast film and a method for preparing the same.

Background

At present, the processing process of the polyethylene casting film is to fill polyethylene matrix resin with inorganic filler mainly containing calcium carbonate, then prepare a film in a casting mode, and then apply unidirectional or bidirectional stretching action to the film to separate the matrix resin from the surfaces of filler particles and develop mutually communicated pore channels among the filler particles, thereby forming the microporous breathable film. The microporous breathable film has the characteristics of allowing water vapor to diffuse and permeate, but blocking liquid water leakage, so that the microporous breathable film is widely applied to manufacturing products such as sanitary protection products and breathable waterproof cloth.

However, since the polyethylene casting film is degraded very slowly in the natural environment, it poses a great threat to the environment. Therefore, in order to accelerate the degradation speed of the polyethylene casting film, natural polymer substances such as starch, cellulose and the like are generally added into a polyethylene material to prepare the biodegradable polyethylene casting film, and in order to improve the plasticity of the natural polymer substances such as starch, cellulose and the like, a plasticizer is also adopted to be matched with the natural polymer substances such as starch and the like in the actual production process, so that the biodegradable polyethylene casting film has the advantages of no toxicity, light pollution in the production process, good biocompatibility, strong flexibility, easy processing and the like. However, it was found through trial and error that although the addition of plasticizers can increase the ductility and flexibility of the polyethylene cast film, it can significantly decrease its tensile strength.

Therefore, how to make the biodegradable polyethylene casting film have excellent ductility and flexibility and higher strength is an important problem to be solved at present.

Disclosure of Invention

In order to solve the technical problems, the application provides a high-strength degradable polyethylene casting film and a preparation method thereof.

In a first aspect, the application provides a high-strength degradable polyethylene casting film, which adopts the following technical scheme:

the high-strength degradable polyethylene casting film comprises the following raw materials in parts by weight: 290-300 parts of matrix resin, 210-220 parts of calcium carbonate, 35-45 parts of starch, 5-11 parts of defoamer, 3-5 parts of pigment master batch, 0.1-0.3 part of opening agent, 4.2-4.6 parts of coupling agent, 78-87 parts of plasticizer, 8.7-9.0 parts of modified sepiolite powder, 5.6-6.6 parts of eggshell powder, 8.7-9.3 parts of triglycerin monostearate and 14-15 parts of interfacial compatilizer; the modified sepiolite powder is sepiolite powder modified by adopting a surfactant.

Through adopting above-mentioned technical scheme, this application adopts matrix resin, calcium carbonate and starch to mix and makes biodegradable polyethylene curtain coating membrane, compares with ordinary polyethylene curtain coating membrane, and degradation speed is obviously accelerated. Meanwhile, the plasticizer is added into the polyethylene casting film, acting force between matrix resins is weakened, and the action of lubricating the movement of high polymer chains in the matrix resins is achieved, so that the plasticization and fluidity of the polyethylene casting film are greatly enhanced, the relative movement of the inside of a molecular chain segment is increased, and the elongation and flexibility of the polyethylene casting film are improved.

In order to solve the problem of strength reduction caused by the plasticizer, egg shell powder and sepiolite powder are added into the polyethylene casting film to serve as reinforcing phases, and the egg shell powder and the sepiolite powder serve as components bearing loads to improve the strength of the polyethylene casting film. The organic component of the eggshell powder has the function of a coupling agent, can enhance the adhesive force between the eggshell powder and components such as starch, calcium carbonate, matrix resin and the like, and can also improve the dispersibility of the eggshell powder in the polyethylene casting film, thereby further improving the mechanical property of the polyethylene casting film. The sepiolite powder is modified by the surfactant, positive charge groups of surfactant molecules are combined with negative charges on the surface of the sepiolite powder, and part of adsorbed water and crystal water are replaced, so that the hydrophobic long carbon chains of the surfactant are adsorbed on the surface of the sepiolite powder, and the sepiolite powder has hydrophilic groups and hydrophobic groups. The modified sepiolite powder is added into the polyethylene casting film and can be matched with a coupling agent, so that the compatibility between the matrix resin and components such as starch, calcium carbonate and the like is obviously improved, and the dispersibility of the modified sepiolite powder in the polyethylene casting film is improved, and the strength and toughness of the polyethylene casting film are further improved.

Meanwhile, the triglycerol monostearate can be matched with the plasticizer to fully wet the matrix resin, the components such as calcium carbonate and starch, and the interfacial tension of the matrix resin, the components such as calcium carbonate and starch is reduced, so that the strength and the toughness of the polyethylene casting film are improved. In addition, the interfacial compatilizer is added into the polyethylene casting film, so that the connection effect between the starch and the matrix resin is achieved, the interfacial compatilizer is matched with the modified sepiolite and the coupling agent together, the synergistic effect is achieved, and the strength and the toughness of the polyethylene casting film are further improved.

In summary, the plasticizer is adopted to improve the flexibility and the processing performance of the biodegradable polyethylene casting film, and on the basis of ensuring the excellent ductility and the flexibility, the strength of the biodegradable polyethylene casting film is obviously improved by using the modified sepiolite powder, the eggshell powder, the triglycerin monostearate, the interfacial compatilizer and the coupling agent in a mixing and matching way.

Preferably, the modified sepiolite powder is prepared by the following method:

dispersing sepiolite in water to prepare a suspension with the mass fraction of 5-7%, performing ultrasonic dispersion for 10-15min, adding dodecyl dimethyl betaine into the suspension, stirring for 20-24h at the temperature of 40-50 ℃, centrifuging for 5-8min at the rotating speed of 4000-4200r/min, washing the precipitate for 4-5 times, drying for 20-24h at the temperature of 40-50 ℃, and grinding to obtain modified sepiolite powder; wherein the weight ratio of the dodecyl dimethyl betaine to the sepiolite is 1 (10-12).

Through adopting above-mentioned technical scheme, this application adopts amphoteric surfactant-dodecyl dimethyl betaine to carry out the modification to the sepiolite, has introduced hydrophobic carbon chain and negative charge group at the sepiolite surface for modified sepiolite powder not only has hydrophilic group, has hydrophobic group again, has improved the dispersibility of sepiolite powder in the polyethylene curtain coating membrane, simultaneously, has improved the compatibility between components such as matrix resin, starch, calcium carbonate to the mechanical properties of polyethylene curtain coating membrane has been improved.

Preferably, the interfacial compatilizer is prepared by the following method:

firstly, stirring polybutylene adipate glycol for 30-35min under the conditions of 100-110 ℃ and 300-350r/min of rotating speed while vacuumizing, then cooling, mixing polybutylene adipate glycol with the weight ratio of (30-32) (11.2-13.2) and 4, 4-diphenylmethane diisocyanate when the temperature is reduced to 50-55 ℃, stirring while vacuumizing, and carrying out heat preservation reaction for 0.8-1.0h when the temperature is increased to 75-85 ℃ to obtain the polyurethane prepolymer interfacial compatibilizer.

By adopting the technical scheme, the polyurethane prepolymer with activity is obtained by reacting the polyester polyol and the polyisocyanate under certain reaction conditions, and is added into the polyethylene casting film as an interfacial compatilizer, and as the active isocyanate group (-NCO) contained at the tail end of the polyurethane prepolymer can be chemically crosslinked with hydroxyl on starch to form a urethane bond, and the polyurethane prepolymer has certain physical compatibility with matrix resin, the polyurethane prepolymer can form a bridge between the starch and the matrix resin, so that the interfacial compatibility between the starch and the matrix resin is improved, and the mechanical property of the polyethylene casting film is enhanced.

Preferably, the matrix resin comprises polyethylene matrix resin and polypropylene matrix resin in a weight ratio of (25-32): 1; wherein the polyethylene matrix resin comprises low density polyethylene, high density polyethylene, linear low density polyethylene and recycled polyethylene in a weight ratio of (20-26): (115-125): (48-52): (90-94).

By adopting the technical scheme, the polypropylene matrix resin is adopted to replace the polyethylene matrix resin partially, and the high-temperature resistance, the chemical stability, the tensile strength, the bending resistance, the flexibility, the tensile strength and other excellent performances of the polypropylene matrix resin are utilized, so that the mechanical property, the high-temperature resistance, the corrosion resistance and other performances of the polyethylene casting film are comprehensively improved. Meanwhile, the polyethylene casting film adopts low-density polyethylene, high-density polyethylene, linear low-density polyethylene and regenerated polyethylene to be mixed and matched to be used as polyethylene matrix resin, so that the polyethylene casting film can have excellent performances such as good mechanical properties, high temperature resistance, corrosion resistance and the like.

Preferably, the plasticizer comprises (0.8-1.0) by weight of glyceryl tricaprylate and sorbitol.

Through adopting above-mentioned technical scheme, the application adopts the mixed collocation of glycerol trioctanoate and sorbitol to use, can exert the synergism between each other, is showing the plasticization and the mobility that improve polyethylene casting film to strengthened the pliability of polyethylene casting film by a wide margin.

Preferably, the raw materials further comprise 5.6-6.0 parts by weight of litsea cubeba oil and 4.8-5.2 parts by weight of clove essential oil.

Through adopting above-mentioned technical scheme, this application still adds litsea cubeba oil and the lilac essential oil of specific use amount to the polyethylene curtain coating membrane, and when the two under the use amount condition of this application, can utilize the lubrication effect of two, improves the toughness of polyethylene curtain coating membrane, strengthens the intensity of polyethylene curtain coating membrane. If the usage amount exceeds the application, excessive essential oil overflows from the polyethylene casting film, and the strength and toughness of the polyethylene casting film are reduced. Meanwhile, experiments prove that the triglycerin monostearate also has certain antibacterial capability, and the addition of the litsea cubeba oil and the butyl essential oil can improve the antibacterial performance of the polyethylene casting film together with the triglycerin monostearate, so that the growth and the propagation of microorganisms such as escherichia coli, staphylococcus aureus and the like are effectively inhibited.

Preferably, the weight ratio of the litsea cubeba oil to the clove essential oil is 1.16:1.

By adopting the technical scheme, the weight ratio of litsea cubeba oil to clove essential oil is further controlled, so that the litsea cubeba oil and the clove essential oil can further exert a synergistic effect, and the mechanical property and the antibacterial property of the polyethylene casting film are further improved.

Preferably, the litsea cubeba oil and the clove essential oil are subjected to embedding treatment by adopting the following method:

a. mixing litsea cubeba oil and clove essential oil uniformly to obtain mixed essential oil;

b. firstly, dissolving hydroxypropyl-beta-cyclodextrin into water to obtain a mixed solution, then adding mixed essential oil into the mixed solution while stirring, homogenizing and emulsifying for 1-1.5h at the rotating speed of 10000-20000r/min to obtain emulsion, and then performing spray drying to obtain mixed essential oil microcapsules;

wherein the weight ratio of the hydroxypropyl-beta-cyclodextrin to the water is (10-14), the weight ratio of the mixed essential oil to the mixed liquid is (86-90), and the weight ratio of the mixed essential oil to the mixed liquid is (1) (30-35).

Through adopting above-mentioned technical scheme, this application further adopts cyclodextrin to carry out the embedding to litsea cubeba oil and butyl essential oil and handles, can effectively promote the stability of two kinds of essential oils to can realize the slow release of two kinds of essential oils, make the two can last to play antibacterial effect.

Preferably, the coupling agent is one of an aluminate coupling agent, stearic acid and a titanate coupling agent.

By adopting the technical scheme, the compatibility among starch, calcium carbonate and matrix resin is improved by adopting one of aluminate coupling agent, stearic acid and titanate coupling agent, so that the mechanical property of the polyethylene casting film is improved.

In a second aspect, the present application provides a method for preparing a high strength degradable polyethylene casting film, comprising the steps of:

s1, mixing and stirring all raw materials for 10-20min at a rotating speed of 500-800r/min to obtain a mixed material;

s2, extruding and granulating the mixed material at 190-195 ℃, drying at 80-90 ℃ for 6-7 hours, casting, stretching and shaping to obtain the polyethylene casting film.

Through adopting above-mentioned technical scheme, this application is first fully mixed with all raw materials for components such as calcium carbonate, starch and matrix resin misce bene, then the rethread screw extruder extrudes the granulation, obtains the special material of polyethylene curtain coating membrane, and carries out the drying to the special material of polyethylene curtain coating membrane, fully gets rid of the moisture in the special material of polyethylene curtain coating membrane, later passes through the curtain coating machine curtain coating formation film, carries out the stretching at last, finalizes the design, obtains the polyethylene curtain coating membrane. The preparation method has simple steps and easy operation, and is suitable for large-scale industrial production.

In summary, the present application includes at least one of the following beneficial technical effects:

1. compared with the common polyethylene casting film, the polyethylene casting film has the advantages of high degradation speed, environmental protection, less pollution to the environment and meeting the requirement of sustainable development;

2. the polyethylene casting film has excellent ductility and toughness, higher strength and good antibacterial property, and can effectively inhibit the growth and reproduction of escherichia coli, staphylococcus aureus and the like;

3. the preparation method of the polyethylene casting film has simple steps and easy operation, and is suitable for large-scale industrial production.

Detailed Description

<Material source>

The raw materials used in the application are all commercially available, and specifically are:

the low density polyethylene of the present application, available from the dow chemical company under the trade designation 722;

the high density polyethylene of the present application, available from the dow chemical company under the designation 3364;

the linear low density polyethylene of the present application, available from bergamot, r Cheng Sujiao, trade name 5220G;

the regenerated polyethylene is purchased from Dongguan city generation plastic technology limited company;

the polypropylene matrix resin of the present application is produced from northern Europe chemical industry under the trademark RD808CF;

the sepiolite of the present application, purchased from Henan province and interior village sepiolite works in county, eastern wind;

the eggshell powder is purchased from Woltesi biotechnology Co., ltd.m. in Lanzhou, and has a particle size of 0.2-0.3 μm;

the trimeric glycerol monostearate of the present application was purchased from shandong duckweed poly biotechnology limited;

dodecyl dimethyl betaine of the present application, available from Shanghai De Yi chemical Co., ltd;

the polybutylene adipate glycol of the application is purchased from Jiangsu Youli letter chemical industry Co., ltd;

4, 4-diphenylmethane diisocyanate of the present application, available from the international trade company of Pandalton (Shanghai);

the glyceryl trioctanoate of the present application was purchased from wuhan Bei Leshe biomedical technologies, inc;

sorbitol of the present application, purchased from shandong duckweed poly biotechnology limited;

the litsea cubeba oil and the clove essential oil are purchased from Jiangxi cedar natural medicinal oil limited company;

the hydroxypropyl-beta-cyclodextrin is purchased from Xiaan Jinxiang pharmaceutical excipients Co.Ltd;

the aluminate coupling agent is purchased from Nanjing Longtian-latitude chemical industry Co., ltd, model JTW-18;

stearic acid of the application is purchased from Nanjing adishi, model 1801;

the titanate coupling agent is purchased from Jinan Haokun chemical industry Co., ltd., model 201;

the defoamer of the present application, produced in Japanese Ai Dike, model B-199;

the color master batch is purchased from Shanghai exhibition industry Co., ltd, and the color is white;

the opening agent of the present application was produced by Korean Letian Chemie under the trademark FC-150U.

<Preparation example>

Preparation example 1

The modified sepiolite powder is prepared by the following method:

dispersing 10kg of sepiolite in water to prepare a suspension with the mass fraction of 5%, carrying out ultrasonic dispersion for 15min, adding 1kg of dodecyl dimethyl betaine into the suspension, stirring for 24h at the temperature of 40 ℃, centrifuging for 8min at the rotating speed of 4000r/min, washing the precipitate for 4 times, drying for 20h at the temperature of 50 ℃, and grinding to obtain the modified sepiolite powder with the D50 particle size of 0.2-0.3 mu m.

Preparation example 2

The modified sepiolite powder is prepared by the following method:

dispersing 10kg of sepiolite in water to prepare a suspension with the mass fraction of 7%, carrying out ultrasonic dispersion for 10min, adding 0.83kg of dodecyl dimethyl betaine into the suspension, stirring for 20h at 50 ℃, centrifuging for 5min at the speed of 4200r/min, washing the precipitate for 5 times, drying for 24h at the temperature of 40 ℃, and grinding to obtain the modified sepiolite powder with the D50 particle size of 0.2-0.3 mu m.

Preparation example 3

The difference from preparation example 2 is that: the sepiolite is modified by adopting a silane coupling agent, and the specific steps are as follows: mixing 10kg of sepiolite with 150L of hydrochloric acid solution with the concentration of 2mol/L, stirring for 12 hours at the temperature of 80 ℃, filtering, washing and drying for 24 hours to obtain acid modified sepiolite powder, adding 200kg of silane coupling agent KH570 hydrolysate with the mass fraction of 2%, regulating the pH value with acetic acid, stirring for 4 hours at the temperature of 95 ℃, washing to be neutral, drying for 12 hours in vacuum, and grinding to obtain the silane coupling agent modified sepiolite powder with the D50 particle size of 0.2-0.3 mu m.

Preparation example 4

The interfacial compatilizer is prepared by the following method:

firstly, stirring polybutylene adipate glycol for 30min under the condition that the temperature is 100 ℃ and the rotating speed is 350r/min while vacuumizing, then cooling, mixing 30kg of polybutylene adipate glycol with 11.2kg of 4, 4-diphenylmethane diisocyanate when the temperature is reduced to 55 ℃, stirring while vacuumizing, and carrying out heat preservation reaction for 1.0h when the temperature is increased to 75 ℃ to obtain the polyurethane prepolymer interfacial compatibilizer.

Preparation example 5

The interfacial compatilizer is prepared by the following method:

firstly, stirring polybutylene adipate glycol for 35min under the condition of 110 ℃ and 300r/min of rotating speed while vacuumizing, then cooling, mixing 32kg of polybutylene adipate glycol and 13.2kg of 4, 4-diphenylmethane diisocyanate when the temperature is reduced to 50 ℃, stirring while vacuumizing, and carrying out heat preservation reaction for 0.8h when the temperature is increased to 85 ℃ to obtain the polyurethane prepolymer interfacial compatibilizer.

<Examples>

Example 1

A preparation method of a high-strength degradable polyethylene casting film comprises the following steps:

s1, at a rotation speed of 500r/min, 290kg of matrix resin {278.85kg of polyethylene matrix resin (20.43 kg of low-density polyethylene, 117.46kg of high-density polyethylene, 49.03kg of linear low-density polyethylene, 91.93kg of regenerated polyethylene), 11.15kg of polypropylene matrix resin }, 220kg of calcium carbonate (D50 with a particle size of 1-3 mu m), 35kg of starch, 11kg of defoamer, 3kg of white master batch, 0.3kg of opening agent, 4.2kg of aluminate coupling agent, 87kg of plasticizer (48.3 kg of tricaprylin, 38.7kg of sorbitol), 8.7kg of modified sepiolite powder prepared in preparation example 1, 6.6kg of eggshell powder, 8.7kg of triglycerin monostearate and 15kg of interfacial compatilizer (citric acid) are mixed and stirred for 20min to obtain a mixed material;

s2, extruding and granulating the mixed material through a double-screw extruder at the temperature of 190 ℃, drying for 6 hours at the temperature of 90 ℃, casting through a casting machine, and stretching at the stretching rate of 150mm/min and the stretching temperature of 75 ℃ with the stretching ratio of 2.6, and performing heat setting for 30 minutes after stretching to obtain the polyethylene casting film.

Example 2

A preparation method of a high-strength degradable polyethylene casting film comprises the following steps:

s1, at a rotation speed of 800r/min, mixing and stirring 300kg of matrix resin {290kg of polyethylene matrix resin (23 kg of low-density polyethylene, 122kg of high-density polyethylene, 51kg of linear low-density polyethylene and 94kg of regenerated polyethylene), 10kg of polypropylene matrix resin }, 210kg of calcium carbonate (D50 with a particle size of 1-3 mu m), 45kg of starch, 5kg of defoamer, 5kg of white master batch, 0.1kg of opening agent, 4.6kg of stearic acid, 78kg of plasticizer (39 kg of glyceryl tricaprylate and 39kg of sorbitol), 9kg of modified sepiolite powder prepared in preparation example 2, 5.6kg of eggshell powder, 9.3kg of triglycerin monostearate and 14kg of interfacial compatilizer (citric acid) for 10min to obtain a mixed material;

s2, extruding and granulating the mixed material through a double-screw extruder at the temperature of 195 ℃, drying for 7 hours at the temperature of 80 ℃, casting through a casting machine, and stretching at the stretching rate of 150mm/min and the stretching temperature of 75 ℃ with the stretching ratio of 2.6, and performing heat setting for 30 minutes after stretching to obtain the polyethylene casting film.

Example 3

A preparation method of a high-strength degradable polyethylene casting film comprises the following steps:

s1, at a rotation speed of 600r/min, 295kg of matrix resin {286.06kg of polyethylene matrix resin (25.04 kg of low-density polyethylene, 120.4kg of high-density polyethylene, 50.08kg of linear low-density polyethylene and 90.54kg of regenerated polyethylene), 8.94kg of polypropylene matrix resin }, 215kg of calcium carbonate (D50 with a particle size of 1-3 μm), 40kg of starch, 8kg of defoamer, 4kg of white master batch, 0.2kg of opening agent, 4.4kg of titanate coupling agent, 82.5kg of plasticizer (43.4 kg of glyceryl tricaprylate, 39.1kg of sorbitol), 8.85kg of modified sepiolite powder prepared in preparation example 1, 6.1kg of eggshell powder, 9kg of triglycerol monostearate and 14.5kg of interfacial compatilizer (citric acid) are mixed and stirred for 15min to obtain a mixed material;

s2, extruding and granulating the mixed material through a double-screw extruder at the temperature of 192 ℃, drying for 6.7 hours at the temperature of 86 ℃, casting through a casting machine, stretching at the stretching rate of 150mm/min and the stretching temperature of 75 ℃ and the stretching ratio of 2.6, and performing heat setting for 30 minutes after stretching to obtain the polyethylene casting film.

Example 4

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 3 in that: in step S1, the interfacial compatibilizer was used as the interfacial compatibilizer prepared in preparation example 4.

Example 5

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 3 in that: in step S1, the interfacial compatibilizer was used as the interfacial compatibilizer prepared in preparation example 5.

Example 6

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 3 in that: in step S1, the trioctanoic acid glyceride in the plasticizer is replaced with xylose.

Example 7

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 3 in that: in step S1, sorbitol in the plasticizer is replaced with xylose.

Example 8

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 3 in that: the plasticizer of step S1 had 55kg of glyceryl tricaprylate and 27.5kg of sorbitol.

Example 9

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 3 in that: 33kg of glyceryl tricaprylate and 49.5kg of sorbitol were included in the plasticizer of step S1.

Example 10

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 3 in that: in the step S1, 5.6kg of litsea cubeba oil and 5.2kg of butyl essential oil are also added into the mixed material.

Example 11

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 3 in that: in the step S1, 6kg of litsea cubeba oil and 4.8kg of butyl essential oil are also added into the mixed material.

Example 12

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 3 in that: in the step S1, 8kg of litsea cubeba oil and 6.4kg of butyl essential oil are also added into the mixed material.

Example 13

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 11 in that: the butyl essential oil is 5kg, and the litsea cubeba oil is 5.8kg.

Example 14

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 13 in that: embedding the clove essential oil and the litsea cubeba oil by adopting the following method:

a. mixing 5.8kg of litsea cubeba oil and 5kg of clove essential oil, and uniformly stirring to obtain 10.8kg of mixed essential oil;

b. 32.4kg of hydroxypropyl-beta-cyclodextrin is dissolved in 291.6kg of water to obtain 324kg of mixed liquid, 10.8kg of mixed essential oil is added into 324kg of mixed liquid while stirring, and then homogenized and emulsified for 1.5h at the rotating speed of 10000r/min to obtain emulsion, and then the emulsion is put into a spray dryer for spray drying to obtain the mixed essential oil microcapsule.

Example 15

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 13 in that: embedding the clove essential oil and the litsea cubeba oil by adopting the following method:

a. mixing 5.8kg of litsea cubeba oil and 5kg of clove essential oil, and uniformly stirring to obtain 10.8kg of mixed essential oil;

b. 52.92kg of hydroxypropyl-beta-cyclodextrin is dissolved in 325.08kg of water to obtain 378kg of mixed liquid, 10.8kg of mixed essential oil is added into 378kg of mixed liquid while stirring, and then homogenizing and emulsifying are carried out for 1h at the rotating speed of 20000r/min to obtain emulsion, and then the emulsion is put into a spray dryer for spray drying to obtain the mixed essential oil microcapsule.

Example 16

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 13 in that: embedding the clove essential oil and the litsea cubeba oil by adopting the following method:

a. firstly, 28.42kg of hydroxypropyl-beta-cyclodextrin is dissolved in 174.58kg of water to obtain 203kg of mixed liquid, then 5.8kg of litsea cubeba oil is added into 203kg of mixed liquid while stirring, and then homogenizing and emulsifying are carried out for 1h at the rotating speed of 20000r/min to obtain emulsion, and then the emulsion is put into a spray dryer for spray drying to obtain litsea cubeba oil microcapsules;

b. dissolving 24.5kg of hydroxypropyl-beta-cyclodextrin in 150.5kg of water to obtain 175kg of mixed solution, adding 5kg of clove essential oil into 175kg of mixed solution while stirring, homogenizing and emulsifying for 1h at the rotating speed of 20000r/min to obtain emulsion, and then placing into a spray dryer for spray drying to obtain the butyl essential oil microcapsule.

Example 17

A method for preparing a high-strength degradable polyethylene casting film, which is different from example 3 in that: in the step S1, 6kg of litsea cubeba oil and 4.8kg of lemon essential oil are also added into the mixed material.

<Comparative example>

Comparative example 1

The difference from example 3 is that: in the step S1, modified sepiolite powder, eggshell powder, triglycerin monostearate and an interfacial compatilizer are not added, and the rest are the same.

Comparative example 2

The difference from example 3 is that: in the step S1, the modified sepiolite powder is modified sepiolite powder prepared in preparation example 3 and subjected to modification treatment by using a silane coupling agent.

Comparative example 3

The difference from example 3 is that: in the step S1, the modified sepiolite powder modified by the surfactant is replaced by the modified montmorillonite modified by the surfactant, and the specific preparation method is shown in' didodecyl dimethyl ammonium bromide modified montmorillonite and the adsorption of the didodecyl dimethyl ammonium bromide modified montmorillonite to pesticide acetamiprid, zhang Yongli and the like, the daily chemical industry, volume 45, 6 th period, and 2015 6 month.

Comparative example 4

The difference from example 3 is that: in the step S1, the modified sepiolite powder modified by the surfactant is replaced by the modified metakaolin modified by the surfactant, and the specific preparation method refers to experimental study of influence of the surfactant modified metakaolin on cement performance, li Song and the like, and is a novel building material.

Comparative example 5

The difference from example 3 is that: in the step S1, the eggshell powder is replaced by talcum powder, and the rest are the same.

Comparative example 6

The difference from example 3 is that: in step S1, no triglyceryl monostearate was added, the remainder being the same.

<Performance detection>

1. Determination of tensile Properties of plastics section 1, reference GB/T1040.1-2018: the polyethylene cast films prepared in examples 1 to 17 and comparative examples 1 to 6 were cut into test pieces of 100mm X45 mm, and then subjected to tensile property test at a tensile speed of 50mm/min, and the test results are shown in Table 1;

2. the polyethylene casting films prepared in examples 1 to 17 and comparative examples 1 to 6 were subjected to impact strength test with reference to GB/T8809-2015 "method of plastic film anti-pendulum impact test", and the test results are shown in Table 1;

3. polyethylene casting films prepared in examples 1 to 17 and comparative examples 1 to 6 were subjected to tests for antibacterial efficiency against Escherichia coli and Staphylococcus aureus with reference to QB/T2591-2003 "antibacterial Plastic-antibacterial Performance test method and antibacterial Effect", and the test results are shown in Table 1.

Table 1 test results table

As can be seen from Table 1, the tensile strength of the polyethylene casting film prepared in examples 1-3 of the application can reach more than 40MPa, the impact strength can reach more than 7.0J, the antibacterial rate to escherichia coli can reach more than 99%, and the antibacterial rate to staphylococcus aureus can reach more than 99.4%, which shows that the polyethylene casting film prepared in the application has higher strength and antibacterial performance on the basis of keeping good toughness.

As can be seen from Table 1, examples 4 to 5 have a tensile strength, impact strength and elongation at break greater than those of example 3, indicating that the use of the polyurethane prepolymer type interfacial compatibilizer can enhance the compatibility between starch and matrix resin, thereby improving the mechanical properties of the polyethylene cast film.

From Table 1, examples 6-7 have slightly lower tensile strength than example 3 and significantly lower impact strength and elongation at break than example 3, indicating that the use of the combination of glyceryl tricaprylate and sorbitol in the present application can exert the synergistic effect of both and enhance the toughness of the polyethylene cast film.

From Table 1, it is understood that examples 8 to 9 have tensile strengths which are not much different from that of example 3, but have impact strengths and elongation at break which are significantly smaller than those of example 3, and it is demonstrated that further control of the weight ratio of glyceryl tricaprylate to sorbitol in the present application can further promote the exertion of the synergistic effect of both, thereby further enhancing the toughness of the polyethylene cast film.

As can be seen from Table 1, the tensile strength, impact strength and elongation at break of examples 10-11 are greater than those of example 3, and the antibacterial rate against Escherichia coli and Staphylococcus aureus is greater than that of example 3, which shows that the mechanical properties and antibacterial properties of the polyethylene cast film can be further improved by adding Litsea cubeba oil and clove essential oil to the polyethylene cast film.

From table 1, it is shown that, although the antibacterial rate of example 12 against escherichia coli and staphylococcus aureus is greater than that of example 3, the tensile strength, impact strength and elongation at break are all smaller than those of example 3, which means that the addition amount of litsea cubeba oil and clove essential oil can be controlled so that the mechanical properties of the polyethylene casting film are not negatively affected by the two.

From table 1, it is known that the tensile strength, impact strength and elongation at break of example 13 are greater than those of example 11, and the antibacterial rate against escherichia coli and staphylococcus aureus is greater than that of example 11, which indicates that the application further controls the weight ratio of litsea cubeba oil to clove essential oil, and can further exert the synergistic effect of the two, thereby further improving the mechanical property and antibacterial property of the polyethylene casting film.

As can be seen from Table 1, the tensile strength, impact strength and elongation at break of examples 14-15 are greater than those of example 13, and the antibacterial rate against Escherichia coli and Staphylococcus aureus is greater than that of example 13, which indicates that the application further embeds the mixed essential oil of litsea cubeba oil and clove essential oil, so that the stability of litsea cubeba oil and clove essential oil can be improved, and the mechanical property and antibacterial property of the ethylene casting film can be further improved.

From table 1, the antibacterial rate of example 16 against escherichia coli and staphylococcus aureus is greater than that of example 13, but less than that of example 15, which shows that the antibacterial performance of the polyethylene casting film can be better improved by embedding the mixture of the clove essential oil and the litsea cubeba oil compared with the independent embedding of the clove essential oil and the litsea cubeba oil.

As can be seen from Table 1, the antibacterial rate of example 17 against Escherichia coli and Staphylococcus aureus is greater than that of example 3, but less than that of example 11, which shows that the synergistic effect of the essential oil and litsea cubeba oil can be better exerted by the mixed and matched use of the essential oil and the litsea cubeba oil, thereby improving the antibacterial performance of the polyethylene casting film.

From table 1, the tensile strength, impact strength and elongation at break of comparative example 1 are smaller than those of example 3, and the antibacterial rate against escherichia coli and staphylococcus aureus is also smaller than that of example 3, which shows that the mechanical property and antibacterial property of the polyethylene casting film can be remarkably improved by adding the modified sepiolite powder, eggshell powder, triglycerin but stearate and interfacial compatilizer into the polyethylene casting film.

From table 1, it is clear that the tensile strength, impact strength and elongation at break of comparative example 2 are smaller than those of example 3, indicating that the modified sepiolite powder modified with the silane coupling agent is less effective in improving the strength of the polyethylene casting film than the modified sepiolite powder modified with the surfactant.

As can be seen from Table 1, the tensile strength, impact strength and elongation at break of comparative examples 3-4 are smaller than those of example 3, indicating that the strength improvement effect on polyethylene casting films is better with the modified sepiolite powder than with other modified inorganic fillers.

From Table 1, it is understood that comparative example 5 has a tensile strength, impact strength and elongation at break less than those of example 3, indicating that replacing eggshells with other inorganic fillers decreases the strength of the polyethylene cast film.

As is clear from Table 1, the tensile strength, impact strength and elongation at break of comparative example 6 are smaller than those of example 3, and the antibacterial rate against E.coli and Staphylococcus aureus is also smaller than that of example 3, indicating that the mechanical properties and antibacterial properties of the polyethylene casting film are reduced without adding the triglyceryl monostearate.

The embodiments of the present invention are all preferred embodiments of the present application, and are not intended to limit the scope of the present application in this way, therefore: all equivalent changes in structure, shape and principle of this application should be covered in the protection scope of this application.

Claims (4)

1. The high-strength degradable polyethylene casting film is characterized in that the used raw materials comprise the following components in parts by weight: 290-300 parts of matrix resin, 210-220 parts of calcium carbonate, 35-45 parts of starch, 5-11 parts of defoamer, 3-5 parts of pigment master batch, 0.1-0.3 part of opening agent, 4.2-4.6 parts of coupling agent, 78-87 parts of plasticizer, 8.7-9.0 parts of modified sepiolite powder, 5.6-6.6 parts of eggshell powder, 8.7-9.3 parts of triglycerin monostearate, 14-15 parts of interfacial compatilizer, 5.6-6.0 parts of litsea cubeba oil and 4.8-5.2 parts of clove essential oil;

the matrix resin comprises polyethylene matrix resin and polypropylene matrix resin with the weight ratio of (25-32) 1; wherein the polyethylene matrix resin comprises low-density polyethylene, high-density polyethylene, linear low-density polyethylene and regenerated polyethylene with the weight ratio of (20-26): 115-125): 48-52): 90-94;

the modified sepiolite powder is prepared by the following method:

dispersing sepiolite in water to prepare a suspension with the mass fraction of 5-7%, performing ultrasonic dispersion for 10-15min, adding dodecyl dimethyl betaine into the suspension, stirring for 20-24h at the temperature of 40-50 ℃, centrifuging for 5-8min at the rotating speed of 4000-4200r/min, washing the precipitate for 4-5 times, drying for 20-24h at the temperature of 40-50 ℃, and grinding to obtain modified sepiolite powder; wherein the weight ratio of the dodecyl dimethyl betaine to the sepiolite is 1 (10-12);

the interfacial compatilizer is prepared by the following method:

firstly, stirring polybutylene adipate glycol for 30-35min under the conditions of 100-110 ℃ and 300-350r/min of rotating speed while vacuumizing, then cooling, mixing polybutylene adipate glycol with the weight ratio of (30-32) (11.2-13.2) and 4, 4-diphenylmethane diisocyanate when the temperature is reduced to 50-55 ℃, stirring while vacuumizing, and carrying out heat preservation reaction for 0.8-1.0h when the temperature is increased to 75-85 ℃ to obtain the polyurethane prepolymer interfacial compatilizer;

the plasticizer comprises (0.8-1.0) tricaprylin and sorbitol in a weight ratio of 1;

the litsea cubeba oil and the clove essential oil are subjected to embedding treatment by adopting the following method:

a. mixing litsea cubeba oil and clove essential oil uniformly to obtain mixed essential oil;

b. firstly, dissolving hydroxypropyl-beta-cyclodextrin into water to obtain a mixed solution, then adding mixed essential oil into the mixed solution while stirring, homogenizing and emulsifying for 1-1.5h at the rotating speed of 10000-20000r/min to obtain emulsion, and then performing spray drying to obtain mixed essential oil microcapsules;

wherein the weight ratio of the hydroxypropyl-beta-cyclodextrin to the water is (10-14), the weight ratio of the mixed essential oil to the mixed liquid is (86-90), and the weight ratio of the mixed essential oil to the mixed liquid is (1) (30-35).

2. The high strength degradable polyethylene casting film according to claim 1, wherein the weight ratio of litsea cubeba oil to clove essential oil is 1.16:1.

3. The high strength degradable polyethylene cast film of claim 1, wherein the coupling agent is one of an aluminate coupling agent, stearic acid, and titanate coupling agent.

4. A method for producing the high-strength degradable polyethylene casting film according to any one of claims 1 to 3, comprising the steps of:

s1, mixing and stirring all raw materials for 10-20min at a rotating speed of 500-800r/min to obtain a mixed material;

s2, extruding and granulating the mixed material at 190-195 ℃, drying at 80-90 ℃ for 6-7 hours, casting, stretching and shaping to obtain the polyethylene casting film.