A composite antioxidant for preparing BOPP film, preparation method and application thereof

Abstract

The present invention belongs to the technical field of antioxidant additive materials, and specifically relates to a composite antioxidant, a preparation method and an application thereof for preparing BOPP film; the raw materials for preparing the composite antioxidant include: 10 to 15 parts of hindered phenol antioxidant, 5 to 10 parts of phosphite antioxidant, 2 to 4 parts of antioxidant AN HP‑136, 1 to 2 parts of vitamin E, and 1 to 2 parts of rosemary extract; the preparation method of the composite antioxidant includes the following steps: S1, according to the raw material ratio in claim 1, the hindered phenol antioxidant and the phosphite antioxidant are mixed evenly to obtain a mixture; S2, antioxidant AN HP‑136, vitamin E and rosemary extract are added to the mixture in sequence, and then heated and mixed and stirred evenly to obtain the composite antioxidant. Hindered phenol antioxidants and phosphite antioxidants provide comprehensive antioxidant protection in the processing of BOPP film, extending the service life of BOPP film; the addition of rosemary extract can effectively remove free radicals, prevent oxidative rancidity of oils and fats, and prevent fading or discoloration caused by oxidation.

Description

Technical Field

[0001] The invention belongs to the technical field of antioxidant additive materials, and in particular relates to a composite antioxidant for preparing BOPP film, a preparation method and application thereof. Background Art

[0002] BOPP film is a very important flexible packaging material. BOPP film is colorless, odorless, tasteless, non-toxic, and has high tensile strength, impact strength, rigidity, toughness and good transparency. BOPP film has low surface energy and needs corona treatment before gluing or printing. After corona treatment, BOPP film has good printing adaptability and can be printed in multiple colors to obtain exquisite appearance, so it is often used as the surface material of composite film.

[0003] Antioxidants are an essential raw material in the preparation of BOPP films. Antioxidants can effectively inhibit or reduce the thermal oxidation reaction rate of plastic macromolecules, delay the thermal and oxygen degradation process of plastic resins, significantly improve the heat resistance of plastic resins, extend the service life of plastic films, and improve the use value of plastic products. Since BOPP films are widely used, they not only need to have a long service life but also good transparency; in order to make the prepared BOPP films have good transparency, we propose a composite antioxidant for preparing BOPP films, a preparation method and its application. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a composite antioxidant for preparing BOPP film, a preparation method and application thereof.

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

[0006] A composite antioxidant for preparing BOPP film, wherein the raw materials for preparing the composite antioxidant include the following components in parts by weight:

[0007]

[0008] 1-2 parts of rosemary extract.

[0009] Furthermore, the hindered phenol antioxidant is at least one of antioxidant 1010, antioxidant 1076 and antioxidant 245.

[0010] Furthermore, the phosphite antioxidant is one of antioxidant 168 and antioxidant TNPP.

[0011] Furthermore, the molecular weight of the antioxidant AN HP-136 is 350.49 and the melting point is 130°C-135°C.

[0012] Furthermore, the content of rosmarinic acid in the rosemary extract is 80-86%, the molecular weight of rosmarinic acid is 360.33, and the melting point is 171° C.-175° C.

[0013] A method for preparing a composite antioxidant for preparing BOPP film, the preparation method comprising the following steps:

[0014] S1. Mixing the hindered phenol antioxidant and the phosphite antioxidant uniformly according to the raw material ratio in claim 1 to obtain a mixture;

[0015] S2. Add antioxidant AN HP-136, vitamin E and rosemary extract to the mixture in sequence, then heat and mix and stir evenly to obtain a composite antioxidant.

[0016] Furthermore, the heating temperature in step S2 is 40°C to 60°C.

[0017] Furthermore, the stirring conditions in step S2 are: the rotation speed is 300-400 rpm, and the stirring time is 30-50 minutes.

[0018] The composite antioxidant for preparing BOPP film described above is used as an additive for preparing BOPP film.

[0019] The beneficial effects of the present invention are as follows: the present invention prepares a composite antioxidant by compounding multiple raw materials including hindered phenol antioxidants, phosphite antioxidants, antioxidant ANHP-136, vitamin E and rosemary extract, and the composite antioxidant is used as a raw material to prepare a BOPP film; the hindered phenol antioxidants and phosphite antioxidants provide comprehensive antioxidant protection during the processing and use of the BOPP film, thereby greatly extending the service life of the BOPP film; the compounding of antioxidant ANHP-136 and vitamin E can reduce impurities and defects in the film, improve the optical uniformity of the film, thereby improving the transparency and glossiness of the BOPP film, making the appearance more beautiful and more suitable for high-quality packaging and printing applications; the addition of rosemary extract can effectively remove free radicals, prevent the oxidation and rancidity of oils and fats, and prevent fading or discoloration caused by oxidation. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Compound Antioxidant A

[0022] S1, mixing 10 parts of hindered phenol antioxidant and 10 parts of phosphite antioxidant to obtain a mixture;

[0023] S2. Add 2 parts of antioxidant AN HP-136, 2 parts of vitamin E and 2 parts of rosemary extract to the mixture in sequence, then heat and mix and stir evenly to obtain composite antioxidant A.

[0024] Compound Antioxidant B

[0025] S1, mixing 15 parts of hindered phenol antioxidant and 5 parts of phosphite antioxidant to obtain a mixture;

[0026] S2. Add 4 parts of antioxidant AN HP-136, 1 part of vitamin E and 1 part of rosemary extract to the mixture in sequence, then heat and mix and stir evenly to obtain composite antioxidant B.

[0027] Compound Antioxidant C

[0028] S1, mixing 10 parts of hindered phenol antioxidant and 5 parts of phosphite antioxidant to obtain a mixture;

[0029] S2. Add 2 parts of antioxidant AN HP-136, 1 part of vitamin E and 1 part of rosemary extract to the mixture in sequence, then heat and mix and stir evenly to obtain composite antioxidant C.

[0030] Compound Antioxidant D

[0031] S1, mixing 10 parts of hindered phenol antioxidant and 10 parts of phosphite antioxidant to obtain a mixture;

[0032] S2. Add 2 parts of antioxidant AN HP-136 and 2 parts of rosemary extract to the mixture in sequence, then heat and mix and stir evenly to obtain composite antioxidant D.

[0033] Compound Antioxidant E

[0034] S1, mixing 10 parts of hindered phenol antioxidant and 10 parts of phosphite antioxidant to obtain a mixture;

[0035] S2. Add 2 parts of vitamin E and 2 parts of rosemary extract to the mixture in sequence, then heat and mix and stir evenly to obtain composite antioxidant E.

[0036] Compound Antioxidant F

[0037] S1, mixing 10 parts of hindered phenol antioxidant and 10 parts of phosphite antioxidant to obtain a mixture;

[0038] S2. Add 2 parts of antioxidant AN HP-136 and 2 parts of vitamin E to the mixture in sequence, then heat and mix and stir evenly to obtain composite antioxidant F.

[0039] Compound Antioxidant G

[0040] S1. Mix 2 parts of antioxidant AN HP-136, 2 parts of vitamin E and 2 parts of rosemary extract, and then heat and stir to obtain composite antioxidant G.

[0041] Example 1

[0042] S1. Raw material mixing: 100 parts of homopolymer polypropylene, 30 parts of pearlescent masterbatch, 35 parts of white masterbatch, 5 parts of lubricant masterbatch, 5 parts of antistatic agent masterbatch and 5 parts of antioxidant A are added into a mixing bin, mixed evenly by stirring, and after drying, enter a melting single screw extruder and a metering single screw extruder connected in series.

[0043] S2. Melt extrusion: The temperature of the heating zone is controlled at 235°C to melt the raw materials. During the melting process, the raw materials are plasticized and mixed under the action of the extruder. The melted melt passes through the coarse filter and the metering pump into the fine filter, and then enters the die head through the three-layer co-extrusion feed block.

[0044] S3, casting: The melt is evenly distributed in the die head and flows out in three layers, and the die head temperature is 240°C. The casting roller is cooled with cold water, and the surface temperature is controlled at 20°C. The melt flows out and cools rapidly on the surface of the casting roller and solidifies into a thick sheet.

[0045] S4, longitudinal stretching: before entering the longitudinal stretching machine, the thick sheet is first heated by a set of preheating rollers, and the temperature setting is gradually increased from 100°C to 120°C, and then stretched three times into a film on the longitudinal stretching machine, the stretching temperature is 115°C, and the longitudinally stretched film is proportionally heat-set on the surface of a set of setting rollers, the setting roller temperature is 80°C, and the longitudinal stretching ratio is 6.

[0046] S5. Transverse stretching: After longitudinal stretching, the film enters the transverse stretching machine. At the entrance of the transverse stretching machine, the film is clamped on both sides by chain clamps. The chain clamps pull the film forward. At the same time, the fan blows hot air to the film from top and bottom through the air duct with uniform air holes to heat the film. The temperature setting is gradually increased from 165℃ to 175℃, and then enters the transverse stretching area. In the stretching area, the width of the chain clamp gradually widens, so that the film is stretched transversely. The stretching temperature is controlled at 170℃. The stretched film is transversely heat-set in the shaping section. The shaping temperature is 90℃ and the transverse stretching ratio is 5-8. Then it is cooled in the cooling section.

[0047] S6. The cooled film is sequentially subjected to online thickness measurement, edge material cutting, static elimination, automatic winding, and aging treatment to obtain a BOPP film.

[0048] Example 2

[0049] In Example 2, compared with Example 1, antioxidant A was replaced by antioxidant B, and other raw materials and preparation conditions were the same as those in Example 1, and a BOPP film was prepared.

[0050] Example 3

[0051] In Example 3, compared with Example 1, antioxidant A was replaced by antioxidant C, and other raw materials and preparation conditions were the same as those in Example 1, and a BOPP film was prepared.

[0052] Example 4

[0053] Compared with Example 1, Example 4 replaces antioxidant A with antioxidant D, and other raw materials and preparation conditions are the same as those in Example 1, to prepare a BOPP film.

[0054] Example 5

[0055] In Example 5, compared with Example 1, antioxidant A was replaced by antioxidant E, and other raw materials and preparation conditions were the same as those in Example 1, and a BOPP film was prepared.

[0056] Example 6

[0057] In Example 6, compared with Example 1, antioxidant A was replaced by antioxidant F, and other raw materials and preparation conditions were the same as those in Example 1, and a BOPP film was prepared.

[0058] Example 7

[0059] In Example 7, compared with Example 1, antioxidant A was replaced by antioxidant G, and other raw materials and preparation conditions were the same as those in Example 1, and a BOPP film was prepared.

[0060] Performance test: The BOPP films prepared in Examples 1 to 7 were subjected to performance tests, specifically including:

[0061] 1. Test the service life of BOPP film through accelerated aging test: Place the BOPP film sample in an aging test chamber, set different parameters such as temperature, humidity and light conditions, and observe the changes in the appearance, mechanical property degradation and barrier property of the sample after a certain period of exposure, so as to infer its service life under normal use conditions. Common test conditions are to place it in an environment with a temperature of 70°C and a relative humidity of 90% for a certain period of time.

[0062] 2. Transmittance test: Use a spectrophotometer for measurement. Place the BOPP film sample between the light source and the detector. The spectrophotometer will emit light in a certain wavelength range. By measuring the intensity of the light after passing through the sample and comparing it with the incident light intensity, the transmittance is calculated, that is, transmittance = transmitted light intensity ÷ incident light intensity × 100%. The higher the transmittance, the better the transparency of the film. This method can accurately quantify the light transmittance of BOPP film.

[0063] 3. Discoloration and fading test: Using ultraviolet lamp as the light source, the ultraviolet light it emits has high energy, which can trigger the photochemical reaction of BOPP film more quickly, resulting in fading. During the test, the BOPP film sample is placed in the ultraviolet aging test box, and the appropriate wavelength and intensity of the ultraviolet lamp, as well as the corresponding test temperature and time, are selected. By comparing the color of the BOPP film before and after aging, its fading degree can be determined; by comparing the color of the BOPP film before and after aging, its discoloration degree can be determined.

[0064] The test results are shown in Table 1:

[0065] Table 1: Performance test results

[0066]

[0067] Conclusion: Combining the data in the table and the different types of additives added in Examples 1 to 7, it can be seen that hindered phenol antioxidants and phosphite antioxidants provide comprehensive antioxidant protection during the processing and use of BOPP film, greatly extending the service life of the BOPP film; the compounding of antioxidant AN HP-136 and vitamin E can reduce impurities and defects in the film, improve the optical uniformity of the film, thereby improving the transparency and gloss of the BOPP film, making it more beautiful in appearance and more suitable for high-quality packaging and printing applications; the addition of rosemary extract can effectively scavenge free radicals, prevent oxidative rancidity of oils and fats, and prevent fading or discoloration caused by oxidation.

[0068] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0069] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A composite antioxidant for preparing BOPP film, characterized in that: The raw materials for preparing the composite antioxidant include the following components by weight: 10-15 parts of hindered phenol antioxidant, 5-10 parts of phosphite antioxidant, Antioxidant AN HP-136 2-4 parts, Vitamin E 1-2 parts, 1-2 parts of rosemary extract.

2. The composite antioxidant for preparing BOPP film according to claim 1, characterized in that: The hindered phenol antioxidant is at least one of antioxidant 1010 , antioxidant 1076 and antioxidant 245 .

3. The composite antioxidant for preparing BOPP film according to claim 2, characterized in that: The phosphite antioxidant is one of antioxidant 168 and antioxidant TNPP.

4. The composite antioxidant for preparing BOPP film according to claim 1, characterized in that: The molecular weight of the antioxidant ANHP-136 is 350.49 and the melting point is 130°C-135°C.

5. The composite antioxidant for preparing BOPP film according to claim 1, characterized in that: The content of rosmarinic acid in the rosemary extract is 80-86%, the molecular weight of rosmarinic acid is 360.33, and the melting point is 171-175°C.

6. A method for preparing a composite antioxidant for preparing BOPP film, characterized in that: The preparation method comprises the following steps: S1. Mixing the hindered phenol antioxidant and the phosphite antioxidant uniformly according to the raw material ratio in claim 1 to obtain a mixture; S2. Add antioxidant AN HP-136, vitamin E and rosemary extract to the mixture in sequence, then heat and mix and stir evenly to obtain a composite antioxidant.

7. The method for preparing a composite antioxidant for preparing BOPP film according to claim 7, characterized in that: The heating temperature in step S2 is 40°C to 60°C.

8. The method for preparing a composite antioxidant for preparing BOPP film according to claim 7, characterized in that: The stirring conditions in step S2 are: a rotation speed of 300 to 400 rpm and a stirring time of 30 to 50 minutes.

9. The composite antioxidant for preparing BOPP film as claimed in any one of claims 1 to 6 is used as an additive for preparing BOPP film.

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