CN116426034A - A nano-calcium carbonate modification method and its application in PE blown film - Google Patents

Abstract

The invention discloses a method for modifying nano-calcium carbonate, which comprises the following steps: (1) preparing calcium hydroxide suspension; (2) preparing calcium carbonate powder; (3) dispersing the calcium carbonate powder in polyethylene glycol Obtain the dispersion liquid in the ethanol solution, drop triethylamine, add tridecafluorooctyltriethoxysilane, solid-liquid separation, solid phase drying, obtain solid phase A; (4) disperse solid phase A in ethanol Form ethanol dispersion in the medium, add chlorogenic acid and dopamine hydrochloride, separate solid and liquid, and dry in solid phase to obtain modified nano-calcium carbonate. After the modified nano-calcium carbonate prepared by the method of the present invention is added to the PE film, the mechanical properties and high temperature and high humidity resistance of the PE film can be significantly improved, the service life of the PE film is improved, and the PE film can be used under high temperature and high humidity. Long-term use in the environment has broadened the application fields and conditions of PE film.

Description

A nano-calcium carbonate modification method and its application in PE blown film

technical field

The invention relates to the technical field of PE materials, in particular to a nano calcium carbonate modification method and its application in PE blown film.

Background technique

As a commonly used inorganic powder filling material for plastics, calcium carbonate can reduce product production costs, improve the dimensional stability, heat resistance, and tensile strength of plastic products, play the role of astigmatism and extinction, and improve the processing and formability of plastics, etc. It has many advantages that other powder materials do not have, so it is widely used in the plastic industry. Polyethylene (PE for short) is a thermoplastic resin obtained by polymerization of ethylene. In industry, it also includes copolymers of ethylene and a small amount of α-olefins. Polyethylene is odorless, non-toxic, feels like wax, has excellent low temperature resistance (the lowest operating temperature can reach -100 ° C ~ -70 ° C), good chemical stability, and can withstand most acid and alkali erosion (not resistant to oxidation) nature of the acid). It is insoluble in common solvents at room temperature, has low water absorption and excellent electrical insulation, so it is widely used in various industries. Polyethylene film is the most widely used polymer material in the world today. PE film is based on special polyethylene (PE) plastic film, which can be divided into high-density polyethylene protective film, medium-density polyethylene and low-density polyethylene according to different densities. Polyethylene film has been widely used in medicine, chemical industry, food, electronics, printing and other industries, but based on some characteristics of polyethylene itself, polyethylene film also has some shortcomings in application, such as the temperature resistance of polyethylene is not good. High, currently the polyethylene film used in the market is generally used at a temperature not exceeding 100°C, so in some special fields the polyethylene film will be limited, and at the same time, in the case of high stress, the polyethylene film is prone to deformation and cracking, so Affecting the service life, these aspects have greatly limited the application of polyethylene film.

Contents of the invention

For this reason, the invention provides a kind of nano calcium carbonate modification method, comprises the steps:

(1) Keep the temperature of the deionized water bath at 80±5°C and keep it warm, then add calcium oxide powder into the deionized water, stir for more than 2 hours after the addition is completed, and then let stand at 80±5°C for more than 15 hours to obtain calcium hydroxide the suspension;

(2) configure the composite aqueous solution of chitosan oligosaccharide and sodium citrate, the suspension of calcium hydroxide is kept at a constant temperature in a water bath to 90 ± 5°C for insulation; stir the suspension of calcium hydroxide at 90 ± 5°C for insulation, Then, in the suspension of the calcium hydroxide, add the composite aqueous solution of the chitosan oligosaccharide and sodium citrate in a stirring state, and simultaneously feed carbon dioxide gas, after the aeration reaction is more than 4h, stop the aeration, and the suspension is air-cooled to Normal temperature, solid-liquid separation, solid phase washing with deionized water, drying to obtain calcium carbonate powder;

(3) Disperse the calcium carbonate powder in the ethanol solution of polyethylene glycol to obtain a dispersion, add dropwise triethylamine to the dispersion, then keep the temperature of the dispersion in a water bath to 70±5°C, and stir the obtained solution after the constant temperature Describe the dispersion liquid, add tridecafluorooctyltriethoxysilane to the dispersion liquid during the stirring process, continue to stir at constant temperature for more than 3 hours after the addition is completed, then stop stirring, air-cool to normal temperature, separate solid-liquid, and dry the solid phase to obtain solid phase A;

(4) Disperse the solid phase A in ethanol to form an ethanol dispersion, keep the temperature of the ethanol dispersion in a water bath to 65±5°C, condense and reflux, add chlorogenic acid and dopamine hydrochloride to the ethanol dispersion after constant temperature , Stir at constant temperature for more than 6 hours after the feeding is completed, then air-cool to room temperature, separate solid and liquid, and dry in solid phase to obtain modified nano-calcium carbonate.

Further, the mass ratio of calcium oxide powder added to the deionized water is calcium oxide powder: deionized water=1:5-6.

Further, in the composite aqueous solution of oligochitosaccharide and sodium citrate, the mass percent of oligochitosaccharide is 3% to 5%, the mass percent of sodium citrate is 0.2% to 0.3%, and the solvent is water; Add the composite aqueous solution of oligochitosaccharide and sodium citrate to the calcium hydroxide suspension in a volume ratio of calcium hydroxide suspension:compound aqueous solution of oligochitosaccharide and sodium citrate=10:2-4.

Further, the introduction rate of the carbon dioxide gas is 0.5m ³ /h.

Further, in the ethanol solution of polyethylene glycol, the concentration of polyethylene glycol is 10-15g/L, and the solid-to-liquid mass ratio of the calcium carbonate powder dispersed in the ethanol solution of polyethylene glycol is solid/ liquid=1:30.

Further, the added mass of the triethylamine is 3 to 5 times the mass of the calcium carbonate powder in the dispersion; the added mass of the tridecafluorooctyltriethoxysilane is 1 to 2 times the powder mass.

Further, the solid-to-liquid mass ratio of the solid phase A dispersed in ethanol is solid/liquid=1:20; the mass ratio of the added mass of the chlorogenic acid and dopamine hydrochloride to the solid phase A is chlorogenic acid : dopamine hydrochloride: solid phase A=1～2:0.3～0.6:1.

The invention also discloses a PE film, which contains the modified nano-calcium carbonate.

The beneficial effect of the present invention is that: after the modified nano-calcium carbonate prepared by the method of the present invention is added to the PE film, the mechanical properties and high temperature and high humidity resistance of the PE film can be significantly improved, the service life of the PE film is improved, and at the same time, the PE film can be used for a long time in high temperature and high humidity environment, which broadens the application fields and conditions of PE film.

Detailed ways

Below in conjunction with embodiment the present invention will be further described.

Example 1

A method for modifying nano-calcium carbonate, comprising the steps of:

(1) Keep the temperature of the deionized water bath at 80±5°C for heat preservation, then add calcium oxide powder to the deionized water, and the mass ratio of adding calcium oxide powder to the deionized water is calcium oxide powder: deionized water=1:5; Stir at 100r/min for 2h after the feeding is completed, then stand for 15h at 80±5°C under heat preservation to obtain a suspension of calcium hydroxide;

(2) configure the composite aqueous solution of oligochitosaccharide and sodium citrate, in the composite aqueous solution of oligochitosaccharide and sodium citrate, the mass percent of chitooligosaccharide is 3%, the mass percent of sodium citrate is 0.2%, solvent It is water; the suspension of calcium hydroxide is kept at a constant temperature in a water bath to 90 ± 5°C; the suspension of calcium hydroxide is stirred at 90 ± 5°C at 60r/min, and then added to the hydrogen under stirring Add the composite aqueous solution of described chitosan oligosaccharide and sodium citrate in the suspension of calcium oxide, add the composite aqueous solution volume ratio of described chitosan oligosaccharide, sodium citrate in the suspension of described calcium hydroxide Suspension of calcium: composite aqueous solution of chitosan oligosaccharide and sodium citrate = 10:2; at the same time, carbon dioxide gas is introduced at a rate of 0.5m ³ /h. After 4 hours of aeration reaction, stop aeration and suspend The liquid is air-cooled to normal temperature, the solid and liquid are separated, the solid phase is washed with deionized water, and dried to obtain calcium carbonate powder;

(3) disperse the calcium carbonate powder in the ethanol solution of polyethylene glycol (PEG-1000) to obtain a dispersion, in the ethanol solution of the polyethylene glycol, the concentration of polyethylene glycol is 10g/L, The solid-to-liquid mass ratio of the calcium carbonate powder dispersed in the ethanol solution of polyethylene glycol is solid/liquid=1:30; triethylamine is added dropwise in the dispersion liquid, and then the dispersion liquid water bath is kept at a constant temperature to 70 ± 5 ℃, stir the dispersion liquid at 60r/min after constant temperature, add tridecafluorooctyltriethoxysilane to the dispersion liquid during the stirring process, continue to stir at constant temperature 60r/min for 3h after the addition is completed, wherein the triethylamine The added mass is 3 times of the calcium carbonate powder mass in the dispersion liquid; the added mass of the tridecafluorooctyltriethoxysilane is 2 times of the calcium carbonate powder mass in the dispersion liquid; then stop stirring and air-cool to normal temperature, solid-liquid separation, and solid-phase drying to obtain solid phase A;

(4) The solid phase A is dispersed in ethanol to form an ethanol dispersion, and the solid-to-liquid mass ratio of the solid phase A dispersed in ethanol is solid/liquid=1:20; the ethanol dispersion water bath is kept at a temperature of 65 ±5°C, condensing and refluxing, after constant temperature, add chlorogenic acid and dopamine hydrochloride to the ethanol dispersion, the mass ratio of the added mass of chlorogenic acid and dopamine hydrochloride to the solid phase A is chlorogenic acid:dopamine hydrochloride : solid phase A=1:0.3:1; after the feeding is completed, stir at a constant temperature of 60r/min for 6h, then air-cool to normal temperature, separate the solid and liquid, and dry the solid phase to obtain the modified nano-calcium carbonate.

Example 2

A method for modifying nano-calcium carbonate, comprising the steps of:

(1) Keep the temperature of the deionized water bath at 80±5°C for heat preservation, then add calcium oxide powder to the deionized water, and the mass ratio of adding calcium oxide powder to the deionized water is calcium oxide powder: deionized water=1:5; Stir at 100r/min for 2h after the feeding is completed, then stand for 15h at 80±5°C under heat preservation to obtain a suspension of calcium hydroxide;

(2) configure the composite aqueous solution of chitosan oligosaccharide and sodium citrate, in the composite aqueous solution of chitosan oligosaccharide and sodium citrate, the mass percent of chitosan oligosaccharide is 4%, the mass percent of sodium citrate is 0.2%, solvent It is water; the suspension of calcium hydroxide is kept at a constant temperature in a water bath to 90 ± 5°C; the suspension of calcium hydroxide is stirred at 90 ± 5°C at 60r/min, and then added to the hydrogen under stirring Add the composite aqueous solution of described chitosan oligosaccharide and sodium citrate in the suspension of calcium oxide, add the composite aqueous solution volume ratio of described chitosan oligosaccharide, sodium citrate in the suspension of described calcium hydroxide Suspension of calcium: composite aqueous solution of chitosan oligosaccharide and sodium citrate = 10:3; at the same time, carbon dioxide gas is introduced at a rate of 0.5m ³ /h. After 4 hours of aeration reaction, stop aeration and suspend The liquid is air-cooled to normal temperature, the solid and liquid are separated, the solid phase is washed with deionized water, and dried to obtain calcium carbonate powder;

(3) disperse the calcium carbonate powder in the ethanol solution of polyethylene glycol (PEG-1000) to obtain a dispersion, in the ethanol solution of the polyethylene glycol, the concentration of polyethylene glycol is 12g/L, The solid-to-liquid mass ratio of the calcium carbonate powder dispersed in the ethanol solution of polyethylene glycol is solid/liquid=1:30; triethylamine is added dropwise in the dispersion liquid, and then the dispersion liquid water bath is kept at a constant temperature to 70 ± 5 ℃, stir the dispersion liquid at 60r/min after constant temperature, add tridecafluorooctyltriethoxysilane to the dispersion liquid during the stirring process, continue to stir at constant temperature 60r/min for 3h after the addition is completed, wherein the triethylamine The added quality is 4 times of the calcium carbonate powder quality in the dispersion liquid; the added quality of the tridecafluorooctyltriethoxysilane is 2 times of the calcium carbonate powder quality in the dispersion liquid; then stop stirring and air-cool to normal temperature, solid-liquid separation, and solid-phase drying to obtain solid phase A;

(4) The solid phase A is dispersed in ethanol to form an ethanol dispersion, and the solid-to-liquid mass ratio of the solid phase A dispersed in ethanol is solid/liquid=1:20; the ethanol dispersion water bath is kept at a temperature of 65 ±5°C, condensing and refluxing, after constant temperature, add chlorogenic acid and dopamine hydrochloride to the ethanol dispersion, the mass ratio of the added mass of chlorogenic acid and dopamine hydrochloride to the solid phase A is chlorogenic acid:dopamine hydrochloride : solid phase A=1:0.4:1; after the feeding is completed, stir at a constant temperature of 60r/min for 6h, then air-cool to normal temperature, separate the solid and liquid, and dry the solid phase to obtain the modified nano-calcium carbonate.

Example 3

A method for modifying nano-calcium carbonate, comprising the steps of:

(1) Keep the temperature of the deionized water bath at 80±5°C for heat preservation, then add calcium oxide powder to the deionized water, and the mass ratio of adding calcium oxide powder to the deionized water is calcium oxide powder: deionized water=1:6; Stir at 100r/min for 2h after the feeding is completed, then stand for 15h at 80±5°C under heat preservation to obtain a suspension of calcium hydroxide;

(2) configure the composite aqueous solution of oligochitosaccharide and sodium citrate, in the composite aqueous solution of oligochitosaccharide and sodium citrate, the mass percent of chitooligosaccharide is 4%, the mass percent of sodium citrate is 0.3%, solvent It is water; the suspension of calcium hydroxide is kept at a constant temperature in a water bath to 90 ± 5°C; the suspension of calcium hydroxide is stirred at 90 ± 5°C at 60r/min, and then added to the hydrogen under stirring Add the composite aqueous solution of described chitosan oligosaccharide and sodium citrate in the suspension of calcium oxide, add the composite aqueous solution volume ratio of described chitosan oligosaccharide, sodium citrate in the suspension of described calcium hydroxide Suspension of calcium: composite aqueous solution of chitosan oligosaccharide and sodium citrate = 10:3; at the same time, carbon dioxide gas is introduced at a rate of 0.5m ³ /h. After 4 hours of aeration reaction, stop aeration and suspend The liquid is air-cooled to normal temperature, the solid and liquid are separated, the solid phase is washed with deionized water, and dried to obtain calcium carbonate powder;

(3) disperse the calcium carbonate powder in the ethanol solution of polyethylene glycol (PEG-1000) to obtain a dispersion, in the ethanol solution of the polyethylene glycol, the concentration of polyethylene glycol is 14g/L, The solid-to-liquid mass ratio of the calcium carbonate powder dispersed in the ethanol solution of polyethylene glycol is solid/liquid=1:30; triethylamine is added dropwise in the dispersion liquid, and then the dispersion liquid water bath is kept at a constant temperature to 70 ± 5 ℃, stir the dispersion liquid at 60r/min after constant temperature, add tridecafluorooctyltriethoxysilane to the dispersion liquid during the stirring process, continue to stir at constant temperature 60r/min for 3h after the addition is completed, wherein the triethylamine The added quality is 4 times of the calcium carbonate powder quality in the dispersion liquid; the added quality of the tridecafluorooctyltriethoxysilane is 2 times of the calcium carbonate powder quality in the dispersion liquid; then stop stirring and air-cool to normal temperature, solid-liquid separation, and solid-phase drying to obtain solid phase A;

(4) The solid phase A is dispersed in ethanol to form an ethanol dispersion, and the solid-to-liquid mass ratio of the solid phase A dispersed in ethanol is solid/liquid=1:20; the ethanol dispersion water bath is kept at a temperature of 65 ±5°C, condensing and refluxing, after constant temperature, add chlorogenic acid and dopamine hydrochloride to the ethanol dispersion, the mass ratio of the added mass of chlorogenic acid and dopamine hydrochloride to the solid phase A is chlorogenic acid:dopamine hydrochloride : solid phase A=2:0.5:1; after the feeding is completed, stir at a constant temperature of 60r/min for 6h, then air-cool to normal temperature, separate the solid and liquid, and dry the solid phase to obtain the modified nano-calcium carbonate.

Example 4

A method for modifying nano-calcium carbonate, comprising the steps of:

(1) Keep the temperature of the deionized water bath at 80±5°C for heat preservation, then add calcium oxide powder to the deionized water, and the mass ratio of adding calcium oxide powder to the deionized water is calcium oxide powder: deionized water=1:6; Stir at 100r/min for 2h after the feeding is completed, then stand for 15h at 80±5°C under heat preservation to obtain a suspension of calcium hydroxide;

(2) configure the composite aqueous solution of oligochitosaccharide and sodium citrate, in the composite aqueous solution of oligochitosaccharide and sodium citrate, the mass percent of chitooligosaccharide is 5%, the mass percent of sodium citrate is 0.3%, solvent It is water; the suspension of calcium hydroxide is kept at a constant temperature in a water bath to 90 ± 5°C; the suspension of calcium hydroxide is stirred at 90 ± 5°C at 60r/min, and then added to the hydrogen under stirring Add the composite aqueous solution of described chitosan oligosaccharide and sodium citrate in the suspension of calcium oxide, add the composite aqueous solution volume ratio of described chitosan oligosaccharide, sodium citrate in the suspension of described calcium hydroxide Suspension of calcium: composite aqueous solution of chitosan oligosaccharide and sodium citrate = 10:4; at the same time, carbon dioxide gas is passed in at a rate of 0.5m ³ /h. After 4 hours of aeration reaction, stop aeration and suspend The liquid is air-cooled to normal temperature, the solid and liquid are separated, the solid phase is washed with deionized water, and dried to obtain calcium carbonate powder;

(3) disperse the calcium carbonate powder in the ethanol solution of polyethylene glycol (PEG-1000) to obtain a dispersion, in the ethanol solution of the polyethylene glycol, the concentration of polyethylene glycol is 15g/L, The solid-to-liquid mass ratio of the calcium carbonate powder dispersed in the ethanol solution of polyethylene glycol is solid/liquid=1:30; triethylamine is added dropwise in the dispersion liquid, and then the dispersion liquid water bath is kept at a constant temperature to 70 ± 5 ℃, stir the dispersion liquid at 60r/min after constant temperature, add tridecafluorooctyltriethoxysilane to the dispersion liquid during the stirring process, continue to stir at constant temperature 60r/min for 3h after the addition is completed, wherein the triethylamine The added quality is 5 times of the calcium carbonate powder quality in the dispersion liquid; the added quality of the tridecafluorooctyltriethoxysilane is 2 times of the calcium carbonate powder quality in the dispersion liquid; then stop stirring, and air-cool to normal temperature, solid-liquid separation, and solid-phase drying to obtain solid phase A;

(4) The solid phase A is dispersed in ethanol to form an ethanol dispersion, and the solid-to-liquid mass ratio of the solid phase A dispersed in ethanol is solid/liquid=1:20; the ethanol dispersion water bath is kept at a temperature of 65 ±5°C, condensing and refluxing, after constant temperature, add chlorogenic acid and dopamine hydrochloride to the ethanol dispersion, the mass ratio of the added mass of chlorogenic acid and dopamine hydrochloride to the solid phase A is chlorogenic acid:dopamine hydrochloride : solid phase A=2:0.6:1; after the feeding is completed, stir at a constant temperature of 60r/min for 6h, then air-cool to normal temperature, separate the solid and liquid, and dry the solid phase to obtain the modified nano-calcium carbonate.

Comparative example 1

A kind of calcium carbonate modification method as contrast, comprises the steps:

(1) Keep the temperature of the deionized water bath at 80±5°C for heat preservation, then add calcium oxide powder to the deionized water, and the mass ratio of adding calcium oxide powder to the deionized water is calcium oxide powder: deionized water=1:5; Stir at 100r/min for 2h after the feeding is completed, then stand for 15h at 80±5°C under heat preservation to obtain a suspension of calcium hydroxide;

(2) configure an aqueous solution of sodium citrate, in the aqueous solution of sodium citrate, the mass percent of sodium citrate is 0.2%, and the solvent is water; the suspension of calcium hydroxide is kept at a constant temperature in a water bath to 90 ± 5° C. 60r/min stirring the suspension of calcium hydroxide under 90 ± 5 ℃ insulation state, then adding the aqueous solution of sodium citrate to the suspension of calcium hydroxide under stirring, adding the hydrogen Add the aqueous solution volume ratio of described sodium citrate in the suspension of calcium oxide to be the suspension of calcium hydroxide: the aqueous solution of sodium citrate=10:3; Pass into carbon dioxide gas simultaneously, the feeding speed of carbon dioxide gas is 0.5 m ³ /h, after 4 hours of aeration reaction, stop the aeration, air-cool the suspension to normal temperature, separate the solid and liquid, wash the solid phase with deionized water, and dry to obtain calcium carbonate powder;

(3) disperse the calcium carbonate powder in the ethanol solution of polyethylene glycol (PEG-1000) to obtain a dispersion, in the ethanol solution of the polyethylene glycol, the concentration of polyethylene glycol is 12g/L, The solid-to-liquid mass ratio of the calcium carbonate powder dispersed in the ethanol solution of polyethylene glycol is solid/liquid=1:30; triethylamine is added dropwise in the dispersion liquid, and then the dispersion liquid water bath is kept at a constant temperature to 70 ± 5 ℃, stir the dispersion liquid at 60r/min after constant temperature, add tridecafluorooctyltriethoxysilane to the dispersion liquid during the stirring process, continue to stir at constant temperature 60r/min for 3h after the addition is completed, wherein the triethylamine The added quality is 4 times of the calcium carbonate powder quality in the dispersion liquid; the added quality of the tridecafluorooctyltriethoxysilane is 2 times of the calcium carbonate powder quality in the dispersion liquid; then stop stirring and air-cool to normal temperature, solid-liquid separation, and solid-phase drying to obtain solid phase A;

(4) The solid phase A is dispersed in ethanol to form an ethanol dispersion, and the solid-to-liquid mass ratio of the solid phase A dispersed in ethanol is solid/liquid=1:20; the ethanol dispersion water bath is kept at a temperature of 65 ±5°C, condensing and refluxing, after constant temperature, add chlorogenic acid and dopamine hydrochloride to the ethanol dispersion, the mass ratio of the added mass of chlorogenic acid and dopamine hydrochloride to the solid phase A is chlorogenic acid:dopamine hydrochloride : solid phase A=1:0.4:1; after the feeding is completed, stir at a constant temperature of 60r/min for 6h, then air-cool to normal temperature, separate the solid and liquid, and dry the solid phase to obtain the modified nano-calcium carbonate of this comparative example.

Comparative example 2

A kind of calcium carbonate modification method as contrast, comprises the steps:

(1) Keep the temperature of the deionized water bath at 80±5°C for heat preservation, then add calcium oxide powder to the deionized water, and the mass ratio of adding calcium oxide powder to the deionized water is calcium oxide powder: deionized water=1:5; Stir at 100r/min for 2h after the feeding is completed, then stand for 15h at 80±5°C under heat preservation to obtain a suspension of calcium hydroxide;

(2) configure the composite aqueous solution of chitosan oligosaccharide and sodium citrate, in the composite aqueous solution of chitosan oligosaccharide and sodium citrate, the mass percent of chitosan oligosaccharide is 4%, the mass percent of sodium citrate is 0.2%, solvent It is water; the suspension of calcium hydroxide is kept at a constant temperature in a water bath to 90 ± 5°C; the suspension of calcium hydroxide is stirred at 90 ± 5°C at 60r/min, and then added to the hydrogen under stirring Add the composite aqueous solution of described chitosan oligosaccharide and sodium citrate in the suspension of calcium oxide, add the composite aqueous solution volume ratio of described chitosan oligosaccharide, sodium citrate in the suspension of described calcium hydroxide Suspension of calcium: composite aqueous solution of chitosan oligosaccharide and sodium citrate = 10:3; at the same time, carbon dioxide gas is introduced at a rate of 0.5m ³ /h. After 4 hours of aeration reaction, stop aeration and suspend The liquid is air-cooled to normal temperature, the solid and liquid are separated, the solid phase is washed with deionized water, and dried to obtain calcium carbonate powder;

(3) The calcium carbonate powder is dispersed in ethanol to form an ethanol dispersion, and the solid-to-liquid mass ratio of the calcium carbonate powder dispersed in ethanol is solid/liquid=1:20; ±5°C, condensing and refluxing, after constant temperature, add chlorogenic acid and dopamine hydrochloride to the ethanol dispersion, the mass ratio of the added mass of chlorogenic acid and dopamine hydrochloride to the calcium carbonate powder is chlorogenic acid: dopamine hydrochloride : Calcium carbonate powder=1:0.4:1; Stir at a constant temperature of 60r/min for 6h after the feeding is completed, then air-cool to normal temperature, separate solid and liquid, and dry in solid phase to obtain the modified nano-calcium carbonate of this comparative example.

Comparative example 3

A kind of calcium carbonate modification method as contrast, comprises the steps:

(1) Keep the temperature of the deionized water bath at 80±5°C for heat preservation, then add calcium oxide powder to the deionized water, and the mass ratio of adding calcium oxide powder to the deionized water is calcium oxide powder: deionized water=1:5; Stir at 100r/min for 2h after the feeding is completed, then stand for 15h at 80±5°C under heat preservation to obtain a suspension of calcium hydroxide;

(2) configure the composite aqueous solution of chitosan oligosaccharide and sodium citrate, in the composite aqueous solution of chitosan oligosaccharide and sodium citrate, the mass percent of chitosan oligosaccharide is 4%, the mass percent of sodium citrate is 0.2%, solvent It is water; the suspension of calcium hydroxide is kept at a constant temperature in a water bath to 90 ± 5°C; the suspension of calcium hydroxide is stirred at 90 ± 5°C at 60r/min, and then added to the hydrogen under stirring Add the composite aqueous solution of described chitosan oligosaccharide and sodium citrate in the suspension of calcium oxide, add the composite aqueous solution volume ratio of described chitosan oligosaccharide, sodium citrate in the suspension of described calcium hydroxide Suspension of calcium: composite aqueous solution of chitosan oligosaccharide and sodium citrate = 10:3; at the same time, carbon dioxide gas is introduced at a rate of 0.5m ³ /h. After 4 hours of aeration reaction, stop aeration and suspend The liquid is air-cooled to normal temperature, the solid and liquid are separated, the solid phase is washed with deionized water, and dried to obtain calcium carbonate powder;

(3) disperse the calcium carbonate powder in the ethanol solution of polyethylene glycol (PEG-1000) to obtain a dispersion, in the ethanol solution of the polyethylene glycol, the concentration of polyethylene glycol is 12g/L, The solid-to-liquid mass ratio of the calcium carbonate powder dispersed in the ethanol solution of polyethylene glycol is solid/liquid=1:30; triethylamine is added dropwise in the dispersion liquid, and then the dispersion liquid water bath is kept at a constant temperature to 70 ± 5 ℃, stir the dispersion liquid at 60r/min after constant temperature, add tridecafluorooctyltriethoxysilane to the dispersion liquid during the stirring process, continue to stir at constant temperature 60r/min for 3h after the addition is completed, wherein the triethylamine The added quality is 4 times of the calcium carbonate powder quality in the dispersion liquid; the added quality of the tridecafluorooctyltriethoxysilane is 2 times of the calcium carbonate powder quality in the dispersion liquid; then stop stirring and air-cool to normal temperature, solid-liquid separation, and solid-phase drying to obtain the modified nano-calcium carbonate in this comparative example.

Example 5

Add the nano-calcium carbonate prepared by the method described in the above examples or comparative examples into the PE film, and perform a performance test on the PE film. The PE film production method is: take each component by the following parts by weight: 100 parts of polyethylene resin (weight-average molecular weight 28000), 20 parts of nanometer calcium carbonate (respectively select the method prepared by the above-mentioned each embodiment or comparative example) product), 5 parts of polyurethane (weight-average molecular weight 20000), 2 parts of dibutyltin maleate, 5 parts of sodium stearate, the above-mentioned components were mixed uniformly at 195°C, kneaded for 40min, and then Extruded at 210°C, the extruded material is hot-calendered at 180°C with a pressure of 20t; then the calendered film is biaxially stretched with a stretch ratio of 1.2, and heat-set at 130°C for 5 minutes after stretching. A PE film (both thickness 60 μm) was obtained. According to the method described in the national standard GB/T 1040.3-2006, the tensile strength of the PE film containing calcium carbonate prepared in the above examples or comparative examples was tested, and the results are shown in Table 1. According to the method described in the national standard GB/T2423.3-2016, the high-temperature and high-humidity aging resistance of the PE film comprising calcium carbonate prepared in the above-mentioned embodiments or comparative examples is tested, wherein the temperature of the test in the test chamber is 85 ± 2 ° C, The humidity is 85%±2%. Cut each group of PE films into 100mm×100mm samples, put them in the test box, observe and record the appearance of the film surface once every 100 hours, until the PE film shrinks and bulges, it is the end point of the test. The results are shown in Table 1.

Table 1

test group Tensile strength (MPa) High temperature and high humidity aging time/h Example 1 22.6 2700 Example 2 23.1 2800 Example 3 22.9 2700 Example 4 22.8 2700 Comparative example 1 19.1 2100 Comparative example 2 18.3 1500 Comparative example 3 18.7 1600

As can be seen from Table 1, after the modified nano-calcium carbonate prepared by the method of the present invention is added to the PE film, the mechanical properties and high-temperature and high-humidity resistance of the PE film can be significantly improved, mainly because the modified nano-calcium carbonate The dispersion performance in the PE matrix is good, and the surface state of the modified calcium carbonate particles is optimized. The infiltration and bonding between the particles and the PE matrix are strong, and it is not easy to produce defects such as microcracks, so the mechanics and weather resistance are improved.

The technical solution provided by the present invention has been introduced in detail above. For those of ordinary skill in the art, according to the ideas of the embodiments of the present invention, there will be changes in the specific implementation and application range. In summary, this The content of the description should not be construed as limiting the present invention.

Claims (8)

1. The nano calcium carbonate modification method is characterized by comprising the following steps of:

(1) Keeping the deionized water in a water bath at a constant temperature of 80+/-5 ℃ for heat preservation, adding calcium oxide powder into the deionized water, stirring for more than 2 hours after the addition, and standing for more than 15 hours at the heat preservation state of 80+/-5 ℃ to obtain a suspension of calcium hydroxide;

(2) Preparing a compound aqueous solution of chitosan oligosaccharide and sodium citrate, wherein the suspension of calcium hydroxide is subjected to water bath constant temperature to 90+/-5 ℃ and heat preservation; stirring a suspension of calcium hydroxide in a heat preservation state at 90+/-5 ℃, adding a composite aqueous solution of chitosan oligosaccharide and sodium citrate into the suspension of calcium hydroxide in a stirring state, introducing carbon dioxide gas at the same time, stopping ventilation after ventilation reaction for more than 4 hours, cooling the suspension to normal temperature, performing solid-liquid separation, washing a solid phase with deionized water, and drying to obtain calcium carbonate powder;

(3) Dispersing the calcium carbonate powder in an ethanol solution of polyethylene glycol to obtain a dispersion liquid, dropwise adding triethylamine into the dispersion liquid, then keeping the dispersion liquid at a constant temperature of 70+/-5 ℃ in a water bath, stirring the dispersion liquid after keeping the constant temperature, adding tridecafluorooctyl triethoxysilane into the dispersion liquid in the stirring process, continuously keeping the constant temperature for more than 3 hours after the addition, stopping stirring, air-cooling to normal temperature, performing solid-liquid separation, and drying a solid phase to obtain a solid phase A;

(4) Dispersing the solid phase A in ethanol to form ethanol dispersion, carrying out water bath constant temperature to 65+/-5 ℃, condensing and refluxing, adding chlorogenic acid and dopamine hydrochloride into the ethanol dispersion after constant temperature, stirring for more than 6 hours at constant temperature after the addition, then carrying out air cooling to normal temperature, carrying out solid-liquid separation, and drying the solid phase to obtain the modified nano calcium carbonate.

2. The method for modifying nano calcium carbonate according to claim 1, wherein the mass ratio of the calcium oxide powder added into deionized water is as follows: deionized water=1:5-6.

3. The method for modifying nano calcium carbonate according to claim 1, wherein the mass percent of the chitosan oligosaccharide is 3-5%, the mass percent of the sodium citrate is 0.2-0.3% and the solvent is water in the composite aqueous solution of the chitosan oligosaccharide and the sodium citrate; adding the chitosan oligosaccharide and sodium citrate composite aqueous solution into the calcium hydroxide suspension, wherein the volume ratio of the chitosan oligosaccharide to the sodium citrate composite aqueous solution is the calcium hydroxide suspension: chitosan oligosaccharide and sodium citrate in the water solution=10:2-4.

4. The method for modifying nano calcium carbonate according to claim 1, wherein the carbon dioxide gas is introduced at a rate of 0.5m ³ /h。

5. The method for modifying nano calcium carbonate according to claim 1, wherein the concentration of polyethylene glycol in the ethanol solution of polyethylene glycol is 10-15 g/L, and the solid-liquid mass ratio of the calcium carbonate powder dispersed in the ethanol solution of polyethylene glycol is solid/liquid=1:30.

6. The method for modifying nano calcium carbonate according to claim 1, wherein the addition mass of the triethylamine is 3-5 times of the mass of the calcium carbonate powder in the dispersion liquid; the adding mass of the tridecafluorooctyl triethoxysilane is 1-2 times of the mass of the calcium carbonate powder in the dispersion liquid.

7. The method for modifying nano calcium carbonate according to claim 1, wherein the solid-liquid mass ratio of the solid phase a dispersed in ethanol is solid/liquid=1:20; the mass ratio of the chlorogenic acid to the dopamine hydrochloride to the solid phase A is that the chlorogenic acid: dopamine hydrochloride: solid phase a=1-2:0.3-0.6:1.

8. A PE film comprising the modified nano calcium carbonate according to any one of claims 1 to 7.