Preparation method of modified polypropylene film layer and application of modified polypropylene film layer in aluminum plastic film

Abstract

The invention relates to the technical field of polypropylene film layers, and discloses a preparation method of a modified polypropylene film layer and application of the modified polypropylene film layer in an aluminum-plastic film. Acrylonitrile, 4, 4 '-diaminobiphenyl-2, 2'-diol, formaldehyde, aminopropyltriethoxysilane, nano titanium dioxide and the like are used as raw materials, and the modified polypropylene film layer is prepared through an addition reaction, a Mannich reaction and a hydrolytic condensation reaction. And adding the modified nano titanium dioxide into polypropylene, mixing, carrying out extrusion granulation, and carrying out film casting to obtain the modified polypropylene film layer. The high temperature resistance and the mechanical property of the polypropylene film layer are improved by utilizing a benzoxazine structure, a cyano structure and nano titanium dioxide particles contained in the polypropylene film layer. Tests prove that the polypropylene film prepared by the invention has excellent high temperature resistance and mechanical properties, and has important application value in aluminum plastic films.

Description

Technical Field

[0001] The invention relates to the technical field of polypropylene film layers, in particular to a preparation method of a modified polypropylene film layer and application thereof in an aluminum-plastic film. Background Art

[0002] Aluminum-plastic composite film is referred to as aluminum-plastic film for short. It is generally composed of an outer protective film, an outer adhesive, aluminum foil, an inner adhesive, and an inner polypropylene film layer. It has good encapsulation, moisture resistance, corrosion resistance and other properties. It is a key material for soft-pack lithium battery cell packaging. However, during long-term use, the battery will become hot and even explode at high temperatures. Therefore, in order to meet the high temperature resistance requirements of the aluminum-plastic film, the materials in the aluminum-plastic film need to be modified to enhance the high temperature resistance of the aluminum-plastic film.

[0003] Polypropylene is a thermoplastic synthetic resin with excellent performance. It has the advantages of low density, non-toxicity, easy processing, good insulation performance, etc. It is widely used in the fields of chemical industry, electrical appliances, packaging materials, building materials, etc. Nano-titanium dioxide is an important inorganic functional material with chemical stability, thermal stability, antibacterial properties, etc. It is widely used in the fields of cosmetics, plastics, coatings, etc. However, due to the large specific surface free energy of nano-titanium dioxide, it is very easy to agglomerate during the application process, so it is necessary to modify its surface to improve its dispersibility and compatibility in polymers. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a method for preparing a modified polypropylene film layer and its application in an aluminum-plastic film.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a modified polypropylene film layer, the preparation method comprising:

[0007] (1) Add acrylonitrile, 4,4'-diaminobiphenyl-2,2'-diol and anhydrous aluminum chloride into a flask, heat to 70-80° C., react for 15-24 hours, and after the reaction is completed, distill under reduced pressure, wash with 10% dilute hydrochloric acid and saturated brine in sequence, and dry to obtain intermediate 1; the mass ratio of acrylonitrile, 4,4'-diaminobiphenyl-2,2'-diol and anhydrous aluminum chloride is 1-1.5:1:0.2-0.4;

[0008] Under the catalysis of anhydrous aluminum chloride, acrylonitrile and 4,4'-diaminobiphenyl-2,2'-diol undergo addition reaction to obtain intermediate 1. The reaction process is as follows:

[0009]

[0010] (2) adding formaldehyde and aminopropyltriethoxysilane to a flask containing chloroform solvent, stirring evenly, adding intermediate 1 thereto, heating to 70-85° C., reacting for 4-8 hours, cooling to room temperature after the reaction, filtering, rotary evaporation, and drying to obtain intermediate 2; the mass ratio of formaldehyde, aminopropyltriethoxysilane, and intermediate 1 is 0.3-0.5:1.1-1.5:1;

[0011] The phenolic hydroxyl group contained in the intermediate 1 is reacted with formaldehyde and aminopropyltriethoxysilane through a Mannich reaction to obtain the intermediate 2. The reaction process is as follows:

[0012]

[0013] (3) Add nano-titanium dioxide and intermediate 2 to a flask containing 60-70% ethanol aqueous solution, ultrasonically disperse, adjust the pH to 3-4 with glacial acetic acid, stir and disperse at 40-50° C. for 1-2 hours, wash with deionized water after the reaction, filter, and dry to obtain modified nano-titanium dioxide; the mass ratio of nano-titanium dioxide to intermediate 2 is 1:0.1-0.5;

[0014] The modified nano titanium dioxide is obtained by condensing the hydroxyl groups contained in the nano titanium dioxide with the hydrolyzed silanol groups of the intermediate 2. The reaction process is as follows:

[0015] in It is nano titanium dioxide;

[0016] (4) Add polypropylene, nucleating agent, antioxidant and modified nano titanium dioxide into a high-speed mixer and mix for 2-5 minutes. Then add the mixture into a twin-screw extruder for extrusion granulation, dry it and form a film by casting to obtain a modified polypropylene film layer.

[0017] Furthermore, in (4), the nucleating agent is one of an α-nucleating agent and a β-nucleating agent; and the antioxidant is one of antioxidant 168 and antioxidant 1010.

[0018] Furthermore, in (4), the mass ratio of polypropylene, nucleating agent, antioxidant and modified nano titanium dioxide is 100:0.05-0.2:0.1-0.4:1-5.

[0019] Furthermore, in (4), the extrusion temperature is 180-230°C, the rotation speed is 300-500r / min; and the casting processing temperature is 210-230°C.

[0020] Another object of the present invention is to provide application of the polypropylene film layer of the present invention in aluminum-plastic film.

[0021] The advantages of the present invention are:

[0022] The invention uses acrylonitrile, 4,4'-diaminobiphenyl-2,2'-diol, aminopropyltriethoxysilane, nano titanium dioxide and the like as raw materials, and obtains modified nano titanium dioxide through addition reaction, Mannich reaction and hydrolysis condensation reaction. The raw materials are easily available, the preparation method is simple and the structure is novel. The nano titanium dioxide is added into polypropylene for mixing, extruded for granulation and cast for film formation to obtain a modified polypropylene film layer.

[0023] The nano titanium dioxide particles used in the present invention are easy to agglomerate. The present invention makes them organic, reduces the degree of agglomeration, and increases their compatibility in organic substances. The present invention introduces them into the substrate. The inorganic nano rigid particles can limit the movement of the substrate molecular chain, increase the load heat deformation temperature of the modified polypropylene film layer, and thus improve the high temperature resistance of the modified polypropylene film layer. In addition, the modified polypropylene film layer prepared by the present invention contains a benzoxazine structure and a cyano structure. When heated, the benzoxazine structure can absorb heat and open the ring to form a cross-linked network structure, thereby improving the high temperature resistance of the material; and the cyano group therein can absorb heat when heated to form highly cross-linked structures such as triazine rings and phthalocyanine rings, thereby further improving the high temperature resistance of the polypropylene film layer. The modified polypropylene film layer prepared by the present invention has excellent high temperature resistance. DETAILED DESCRIPTION

[0024] The preparation method and application of the modified polypropylene film layer of the present invention are further described below in conjunction with some specific embodiments. The specific embodiments are for further illustrating the present invention in detail, but do not limit the protection scope of the present invention.

[0025] Example 1

[0026] (1) 6 g of acrylonitrile, 6 g of 4,4'-diaminobiphenyl-2,2'-diol and 2 g of anhydrous aluminum chloride were added to a flask, heated to 75°C and reacted for 15 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with 10% dilute hydrochloric acid and saturated brine, and dried to obtain intermediate 1.

[0027] (2) 0.8 g of formaldehyde and 2.5 g of aminopropyltriethoxysilane were added to a flask containing toluene solvent, stirred evenly, and then 2 g of intermediate 1 was added thereto. The temperature was raised to 75° C. and the reaction was carried out for 6 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, rotary evaporated, and dried to obtain intermediate 2.

[0028] (3) 10 g of nano titanium dioxide and 1 g of intermediate 2 were added to a flask containing 65% ethanol aqueous solution, and ultrasonically dispersed. The pH was adjusted to 3 using glacial acetic acid. The mixture was stirred and dispersed at 45° C. for 2 h. After the reaction was completed, the mixture was washed with deionized water and dried to obtain modified nano titanium dioxide.

[0029] (4) 100 g of polypropylene, 0.1 g of β-nucleating agent, 0.3 g of antioxidant 168, and 1 g of modified nano titanium dioxide were added to a high-speed mixer and mixed for 4 min. The mixture was then added to a twin-screw extruder for extrusion granulation at an extrusion temperature of 220° C. and a rotation speed of 400 r / min. The mixture was dried and film-formed by a casting method at a processing temperature of 210° C. to obtain a modified polypropylene film layer.

[0030] Example 2

[0031] (1) 7.5 g of acrylonitrile, 6 g of 4,4'-diaminobiphenyl-2,2'-diol, and 1.2 g of anhydrous aluminum chloride were added to a flask, heated to 80° C., and reacted for 20 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with 10% dilute hydrochloric acid and saturated brine, and dried to obtain intermediate 1.

[0032] (2) Add 1 g of formaldehyde and 3 g of aminopropyltriethoxysilane to a flask containing toluene solvent, stir evenly, then add 2 g of intermediate 1, heat to 85° C., react for 5 h, and after the reaction is completed, cool to room temperature, filter, rotary evaporate, and dry to obtain intermediate 2.

[0033] (3) 10 g of nano titanium dioxide and 2 g of intermediate 2 were added to a flask containing 65% ethanol aqueous solution, and ultrasonically dispersed. The pH was adjusted to 3 using glacial acetic acid. The mixture was stirred and dispersed at 50° C. for 2 h. After the reaction was completed, the mixture was washed with deionized water and dried to obtain modified nano titanium dioxide.

[0034] (4) 100 g of polypropylene, 0.15 g of α-nucleating agent, 0.3 g of antioxidant 168, and 2 g of modified nano titanium dioxide were added to a high-speed mixer and mixed for 5 min. The mixture was then added to a twin-screw extruder for extrusion granulation at a temperature of 200° C. and a rotation speed of 500 r / min. The mixture was dried and film-formed by a casting method at a processing temperature of 230° C. to obtain a modified polypropylene film layer.

[0035] Example 3

[0036] (1) 8.4 g of acrylonitrile, 6 g of 4,4'-diaminobiphenyl-2,2'-diol, and 2.4 g of anhydrous aluminum chloride were added to a flask, heated to 70° C., and reacted for 16 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with 10% dilute hydrochloric acid and saturated brine, and dried to obtain intermediate 1.

[0037] (2) 0.6 g of formaldehyde and 2.8 g of aminopropyltriethoxysilane were added to a flask containing toluene solvent, stirred evenly, and then 2 g of intermediate 1 was added thereto. The temperature was raised to 80° C. and the reaction was carried out for 4 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, rotary evaporated, and dried to obtain intermediate 2.

[0038] (3) 10 g of nano titanium dioxide and 3 g of intermediate 2 were added to a flask containing 70% ethanol aqueous solution, and ultrasonically dispersed. The pH was adjusted to 4 using glacial acetic acid. The mixture was stirred and dispersed at 45° C. for 2 h. After the reaction was completed, the mixture was washed with deionized water and dried to obtain modified nano titanium dioxide.

[0039] (4) 100 g of polypropylene, 0.2 g of α-nucleating agent, 0.4 g of antioxidant 1010, and 3 g of modified nano titanium dioxide were added to a high-speed mixer and mixed for 2 min. The mixture was then added to a twin-screw extruder for extrusion granulation at a temperature of 200° C. and a rotation speed of 300 r / min. The mixture was dried and film-formed by a casting method at a processing temperature of 220° C. to obtain a modified polypropylene film layer.

[0040] Example 4

[0041] (1) 8 g of acrylonitrile, 6 g of 4,4'-diaminobiphenyl-2,2'-diol, and 1.2 g of anhydrous aluminum chloride were added to a flask, heated to 75° C., and reacted for 18 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with 10% dilute hydrochloric acid and saturated brine, and dried to obtain intermediate 1.

[0042] (2) 0.8 g of formaldehyde and 2.5 g of aminopropyltriethoxysilane were added to a flask containing toluene solvent, stirred evenly, and then 2 g of intermediate 1 was added thereto. The temperature was raised to 70° C. and the reaction was carried out for 6 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, rotary evaporated, and dried to obtain intermediate 2.

[0043] (3) 10 g of nano titanium dioxide and 4 g of intermediate 2 were added to a flask containing 60% ethanol aqueous solution, and ultrasonically dispersed. The pH was adjusted to 3 using glacial acetic acid. The mixture was stirred and dispersed at 40° C. for 1 h. After the reaction was completed, the mixture was washed with deionized water and dried to obtain modified nano titanium dioxide.

[0044] (4) 100 g of polypropylene, 0.1 g of β-nucleating agent, 0.2 g of antioxidant 1010, and 4 g of modified nano titanium dioxide were added to a high-speed mixer and mixed for 4 min. The mixture was then added to a twin-screw extruder for extrusion granulation at an extrusion temperature of 180° C. and a rotation speed of 400 r / min. The mixture was dried and film-formed by a casting method at a processing temperature of 210° C. to obtain a modified polypropylene film layer.

[0045] Example 5

[0046] (1) 9 g of acrylonitrile, 6 g of 4,4'-diaminobiphenyl-2,2'-diol, and 2 g of anhydrous aluminum chloride were added to a flask, heated to 75° C., and reacted for 24 h. After the reaction was completed, the mixture was distilled under reduced pressure, washed with 10% dilute hydrochloric acid and saturated brine, and dried to obtain intermediate 1.

[0047] (2) Add 1 g of formaldehyde and 2.2 g of aminopropyltriethoxysilane to a flask containing toluene solvent, stir evenly, then add 2 g of intermediate 1, heat to 70° C., react for 8 h, and after the reaction is completed, cool to room temperature, filter, rotary evaporate, and dry to obtain intermediate 2.

[0048] (3) 10 g of nano titanium dioxide and 5 g of intermediate 2 were added to a flask containing 70% ethanol aqueous solution, and ultrasonically dispersed. The pH was adjusted to 3 using glacial acetic acid. The mixture was stirred and dispersed at 50° C. for 2 h. After the reaction was completed, the mixture was washed with deionized water and dried to obtain modified nano titanium dioxide.

[0049] (4) 100 g of polypropylene, 0.05 g of α-nucleating agent, 0.1 g of antioxidant 1010, and 5 g of modified nano-titanium dioxide were added to a high-speed mixer and mixed for 5 min. The mixture was then added to a twin-screw extruder for extrusion granulation at a temperature of 230° C. and a rotation speed of 500 r / min. The mixture was dried and film-formed by a casting method at a processing temperature of 220° C. to obtain a modified polypropylene film layer.

[0050] Comparative Example 1

[0051] The difference between this comparative example and Example 1 is that nano titanium dioxide is used in step (4) instead of modified nano titanium dioxide.

[0052] The tensile properties of the polypropylene film layer were tested using a universal electronic testing machine, and then the polypropylene film layer was placed in an oven at 100°C for heat aging for 24 hours, and the tensile properties after heat aging were tested.

[0053] Table 1:

[0054]

[0055] As can be seen from the table, the tensile properties of Example 1 before and after heat aging are better than those of Comparative Example 1. This is because Example 1 not only contains heat-resistant benzoxazine structures and cyano structures, which can enhance the tensile properties after heat aging, but also, in Example 1, the nano titanium dioxide is organically modified and can be evenly dispersed in the polypropylene film layer. When the film is stretched by an external force, the two ends of the inorganic particles are subjected to tensile stress of the polymer matrix, while the middle is subjected to compressive stress. Due to the interaction of forces, it is conducive to the generation of yield, thereby improving its tensile properties. The nano titanium dioxide in Comparative Example 1 is not modified, so its mechanical properties are not as good as those of Example 1. In Examples 1-5, with the increase in the amount of modified nano titanium dioxide, the tensile properties before and after heat aging are also increasing. The maximum tensile strength before heat aging can reach 50.8 MPa, and the maximum tensile strength after heat aging can reach 47.1 MPa. The polypropylene film layer prepared by the present invention has excellent mechanical properties and heat resistance.

[0056] The heat resistance of the modified polypropylene film layer was tested by a thermogravimetric analyzer. The temperature was raised from room temperature to 800°C at a heating rate of 20°C / min in a nitrogen atmosphere.

[0057] Table 2:

[0058] Initial decomposition temperature / ℃ Example 1 432 Example 2 439 Example 3 451 Example 4 456 Example 5 448 Comparative Example 1 415

[0059] It can be seen from the table that the modified polypropylene film layer prepared by the present invention has good heat resistance. The modified polypropylene film layer prepared by the present invention has important application prospects in aluminum-plastic films.

[0060] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a modified polypropylene film layer, characterized in that: The preparation method is: (1) Add acrylonitrile, 4,4'-diaminobiphenyl-2,2'-diol and anhydrous aluminum chloride into a flask, heat to 70-80°C, react for 15-24 hours, and after the reaction is completed, distill under reduced pressure, wash with 10% dilute hydrochloric acid and saturated brine in sequence, and dry to obtain intermediate 1; (2) Add formaldehyde and aminopropyltriethoxysilane to a flask containing chloroform solvent, stir evenly, then add intermediate 1, heat to 70-85° C., react for 4-8 hours, and after the reaction is completed, cool to room temperature, filter, rotary evaporate, and dry to obtain intermediate 2; (3) Add nano-titanium dioxide and intermediate 2 to a flask containing 60-70% ethanol aqueous solution, disperse by ultrasonication, adjust the pH to 3-4 with glacial acetic acid, stir and disperse at 40-50° C. for 1-2 h, and after the reaction is completed, wash with deionized water, filter, and dry to obtain modified nano-titanium dioxide; (4) Add polypropylene, nucleating agent, antioxidant and modified nano titanium dioxide into a high-speed mixer and mix for 2-5 minutes. Then add the mixture into a twin-screw extruder for extrusion granulation, dry it and form a film by casting to obtain a modified polypropylene film layer.

2. The method for preparing a modified polypropylene film layer according to claim 1, characterized in that: In the above (1), the mass ratio of acrylonitrile, 4,4'-diaminobiphenyl-2,2'-diol and anhydrous aluminum chloride is 1-1.5:1:0.2-0.

4.

3. The method for preparing a modified polypropylene film layer according to claim 1, characterized in that: In the above (2), the mass ratio of formaldehyde, aminopropyltriethoxysilane and intermediate 1 is 0.3-0.5:1.1-1.5:

1.

4. The method for preparing a modified polypropylene film layer according to claim 1, characterized in that: In the above (3), the mass ratio of nano titanium dioxide to intermediate 2 is 1:0.1-0.

5.

5. The method for preparing a modified polypropylene film layer according to claim 1, characterized in that: In the above (4), the nucleating agent is one of an α-nucleating agent and a β-nucleating agent; and the antioxidant is one of an antioxidant 168 and an antioxidant 1010.

6. The method for preparing a modified polypropylene film layer according to claim 1, characterized in that: In the above (4), the mass ratio of polypropylene, nucleating agent, antioxidant and modified nano titanium dioxide is 100:0.05-0.2:0.1-0.4:1-5.

7. The method for preparing a modified polypropylene film layer according to claim 1, characterized in that: In the above (4), the extrusion temperature is 180-230°C, the rotation speed is 300-500r / min; and the casting processing temperature is 210-230°C.

8. Use of the polypropylene film layer prepared by the preparation method according to claims 1 to 7 in aluminum-plastic film.

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