Matting material for BOPP (biaxially-oriented polypropylene) matting film as well as preparation method and application of matting material

Abstract

The invention discloses a matting material for a BOPP (biaxially-oriented polypropylene) matting film as well as a preparation method and application thereof, and belongs to the technical field of plastic films, the matting material for the BOPP matting film comprises the following raw materials in percentage by mass: 40-50% of co-polypropylene, 5-10% of LLDPE (linear low density polyethylene), 2-7% of ethylene-propylene block copolymer and 0.3-0.6% of lubricant blend; the content of ethylene in the ethylene-propylene segmented copolymer is 40%; the lubricant blend comprises polyethylene wax, the lubricant blend further comprises any one of calcium stearate and zinc stearate, and the extinction material greatly improves the overall flow dispersibility of the extinction material.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic films, and in particular relates to a matting material for BOPP matting film, a preparation method and application thereof. Background Art

[0002] The matte masterbatch for BOPP matte film is generally an incompatible blend system of copolymerized polypropylene and high-density polyethylene. During the biaxial stretching process, a rough interface morphology is produced due to the different responses of the incompatible system to the stretching. The light irradiated to the rough surface produces diffuse reflection, thereby producing a matte effect. This type of matte material has a good matte effect. At present, it is highly mature in the market and is widely used in matte packaging products. However, this type of matte material also has many problems. During the biaxial stretching process, due to the inconsistent stretching ratios on both sides and in the middle of the BOPP production line, as well as the difference in the crystallization rate of polypropylene and polyethylene, the BOPP matte film generally has uneven matte on both sides of the film or insufficient matte. In particular, the glossiness of the edge of the film is significantly higher than that in the middle, and there are patches of cloud-like matte defects, which seriously affect the overall quality and superior grade rate of the matte film. In order to solve such problems, many manufacturers are forced to increase the thickness of the surface matte layer, which leads to an increase in production costs.

[0003] The matting material formula for traditional BOPP matting film is usually a co-extrusion of copolymerized polypropylene and high-density polyethylene. During the biaxial stretching process, since HDPE crystallizes quickly and is a hard core, while PP crystallizes slowly and is still a soft phase system, PP and PE separate under the stretching action, making the matting surface rough, so as to achieve the matting effect of BOPP matting film. This traditional matting material formula is simple, and the matting on both sides of the film is generally uneven during the biaxial stretching process. Summary of the invention

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

[0005] A matting material for BOPP matting film comprises the following raw materials in percentage by mass: 40% to 50% of copolymerized polypropylene, 5% to 10% of LLDPE, 2% to 7% of ethylene-propylene block copolymer and 0.3% to 0.6% of lubricant blend; the ethylene content in the ethylene-propylene block copolymer is 40%; the lubricant blend comprises polyethylene wax, and the lubricant blend further comprises any one of calcium stearate and zinc stearate.

[0006] Preferably, it also includes 40% to 50% by mass of HDPE; the density of the HDPE is 0.945-0.960 g / cm3.

[0007] Preferably, the invention further comprises 0.1% to 0.3% by mass of an antioxidant, wherein the antioxidant comprises a blend of antioxidant 1010 and antioxidant 168.

[0008] Preferably, the mass ratio of the antioxidant 1010 to the antioxidant 168 is 1:1.

[0009] Preferably, the copolymerized polypropylene includes one or more of a binary copolymer and a ternary copolymer.

[0010] Preferably, the mass ratio of the polyethylene wax to calcium stearate or to zinc stearate is 1:1-3:1.

[0011] Preferably, the density of the LLDPE is 0.924-0.940 g / cm3.

[0012] A method for preparing a matting material for BOPP matting film comprises the following steps:

[0013] The raw material copolymer polypropylene 40%-50%, HDPE 40%-50%, LLDPE 5%-10%, ethylene-propylene block copolymer 2%-7%, lubricant blend 0.3%-0.6% and antioxidant 0.1%-0.3% are mixed in mass percentage, extruded and granulated to obtain matte material for BOPP matte film.

[0014] Preferably, the extrusion temperature is 225-235°C.

[0015] Application of the above matte material or the matte material prepared by the above preparation method in the production of BOPP matte film.

[0016] The beneficial effects of the present invention are:

[0017] (1) The matting material for BOPP matting film of the present invention is prepared by adding low-density linear polyethylene and ethylene-propylene block copolymer into the formulation system. Since the flow rate of low-density linear polyethylene and ethylene-propylene block copolymer with high melt index in the molten state is significantly higher than that of copolymerized polypropylene and high-density polyethylene, the flow dispersibility of the matting material as a whole is greatly improved. At the same time, when polyethylene wax is used as an internal lubricant and stearic acid is used as an external lubricant, the flow between copolymerized polypropylene and high-density polyethylene chains in the matting material can be greatly improved. In summary, the formulation greatly improves the matting uniformity of the whole BOPP matting film, improves the problem of uneven matting at the edge while maintaining the original matting layer thickness, and improves the overall matting effect and production efficiency of the BOPP matting film.

[0018] (2) Uneven matting of edges causes a lot of waste. The matting masterbatch prepared by the present invention greatly reduces the uneven matting of edges in the matting film, bringing higher profits to the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 : Embodiment 2 matting material;

[0021] Figure 2 : Comparative Example 1: Commercially available matte material;

[0022] Figure 3 : DSC curve diagram of the matting material of Example 2. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in 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.

[0024] Example 1

[0025] The matting material for BOPP matte film of the present embodiment contains 45% copolymerized polypropylene, 40% high-density polyethylene, 10% low-density linear polyethylene, 4.6% ethylene-propylene block copolymer, 0.3% lubricant blend, and 0.1% antioxidant, respectively, by weight percentage. The copolymerized polypropylene is specifically a terpolymer with a melt index of 4g / 10min (230°C, 2.16kg), the high-density polyethylene has a melt index of 0.15g / 10min (190°C, 2.16kg), and a density of 0.945g / cm3, the low-density linear polyethylene has a melt index of 20g / 10min (190°C, 2.16kg), and a density of 0.924g / cm3, and the ethylene-propylene block copolymer has a melt index of 10g / 10min (230°C, 2.16kg). The lubricant blend is a mixture of polyethylene wax and zinc stearate in a mass ratio of 2:1, and the antioxidant is a mixture of commercially available BASF 168 and 1010 in a mass ratio of 1:1.

[0026] The preparation method of the matt masterbatch for BOPP matt film described in this embodiment is as follows:

[0027] The raw materials were weighed according to the weight percentage ratio, and copolymerized polypropylene, high-density polyethylene, low-density linear polyethylene, ethylene-propylene copolymer, lubricant and antioxidant were first mixed at a low speed for 3 minutes in a high-speed mixer, and then mixed at a high speed for 1 minute. The mixture was then sucked into the hopper of a twin-screw extruder by a suction machine, extruded into granules at 225°C, and dried.

[0028] Example 2

[0029] The matting material for BOPP matte film of the present embodiment contains 47% copolymerized polypropylene, 45% high-density polyethylene, 5% low-density linear polyethylene, 2.6% ethylene-propylene block copolymer, 0.3% lubricant blend, and 0.1% antioxidant by weight percentage. The copolymerized polypropylene is specifically a terpolymer with a melt index of 7.5g / 10min (230°C, 2.16kg), the high-density polyethylene has a melt index of 0.1g / 10min (190°C, 2.16kg), and a density of 0.960g / cm3, the low-density linear polyethylene has a melt index of 18g / 10min (190°C, 2.16kg), and a density of 0.940g / cm3, and the ethylene-propylene block copolymer has a melt index of 15g / 10min (230°C, 2.16kg). The lubricant blend is a mixture of polyethylene wax and zinc stearate in a mass ratio of 2:1, and the antioxidant is a mixture of commercially available BASF 168 and 1010 in a mass ratio of 1:1.

[0030] The preparation method of the matt masterbatch for BOPP matt film described in this embodiment is as follows:

[0031] The raw materials were weighed according to the weight percentage ratio, and copolymerized polypropylene, high-density polyethylene, low-density linear polyethylene, ethylene-propylene copolymer, lubricant and antioxidant were first mixed at a low speed for 3 minutes in a high-speed mixer, and then mixed at a high speed for 1 minute. The mixture was then sucked into the hopper of a twin-screw extruder by a suction machine, extruded into granules at 235°C, and dried.

[0032] Example 3

[0033] The matting material for BOPP matte film of the present embodiment contains 40% copolymerized polypropylene, 45% high-density polyethylene, 7.1% low-density linear polyethylene, 7% ethylene-propylene block copolymer, 0.6% lubricant blend, and 0.3% antioxidant by weight percentage. The copolymerized polypropylene is specifically a terpolymer with a melt index of 6 g / 10 min (230° C., 2.16 kg), the high-density polyethylene has a melt index of 1.5 g / 10 min (190° C., 2.16 kg), and a density of 0.960 g / cm3, the low-density linear polyethylene has a melt index of 12 g / 10 min (190° C., 2.16 kg), and a density of 0.940 g / cm3, and the ethylene-propylene block copolymer has a melt index of 20 g / 10 min (230° C., 2.16 kg). The lubricant blend is a mixture of polyethylene wax and zinc stearate in a mass ratio of 1:1, and the antioxidant is a compound of commercially available BASF 168 and 1010 in a mass ratio of 1:1.

[0034] The preparation method of the matt masterbatch for BOPP matt film described in this embodiment is as follows:

[0035] The raw materials were weighed according to the weight percentage ratio, and copolymerized polypropylene, high-density polyethylene, low-density linear polyethylene, ethylene-propylene copolymer, lubricant and antioxidant were first mixed at a low speed for 3 minutes in a high-speed mixer, and then mixed at a high speed for 1 minute. The mixture was then sucked into the hopper of a twin-screw extruder by a suction machine, extruded into granules at 230°C, and dried.

[0036] Example 4

[0037] The matting material for BOPP matte film of the present embodiment contains 50% copolymerized polypropylene, 42% high-density polyethylene, 5.5% low-density linear polyethylene, 2% ethylene-propylene block copolymer, 0.3% lubricant blend, and 0.2% antioxidant by weight percentage. The above-mentioned copolymerized polypropylene is specifically a terpolymer with a melt index of 8g / 10min (230°C, 2.16kg), the high-density polyethylene has a melt index of 0.8g / 10min (190°C, 2.16kg), and a density of 0.960g / cm3, the low-density linear polyethylene has a melt index of 10g / 10min (190°C, 2.16kg), and a density of 0.940g / cm3, and the melt index of the ethylene-propylene block copolymer is 12g / 10min (230°C, 2.16kg). The lubricant blend is a mixture of polyethylene wax and zinc stearate in a mass ratio of 3:1, and the antioxidant is a mixture of commercially available BASF 168 and 1010 in a mass ratio of 1:1.

[0038] The preparation method of the matt masterbatch for BOPP matt film described in this embodiment is as follows:

[0039] The raw materials were weighed according to the weight percentage ratio, and copolymerized polypropylene, high-density polyethylene, low-density linear polyethylene, ethylene-propylene copolymer, lubricant and antioxidant were first mixed at a low speed for 3 minutes in a high-speed mixer, and then mixed at a high speed for 1 minute. The mixture was then sucked into the hopper of a twin-screw extruder by a suction machine, extruded into granules at 235°C, and dried.

[0040] Example 5

[0041] The matting material for BOPP matte film of the present embodiment contains 42% copolymerized polypropylene, 50% high-density polyethylene, 5% low-density linear polyethylene, 2.3% ethylene-propylene block copolymer, 0.6% lubricant blend, and 0.1% antioxidant by weight percentage. The copolymerized polypropylene is specifically a terpolymer with a melt index of 5.5g / 10min (230°C, 2.16kg), the high-density polyethylene has a melt index of 1.0g / 10min (190°C, 2.16kg), and a density of 0.950g / cm3, the low-density linear polyethylene has a melt index of 15g / 10min (190°C, 2.16kg), and a density of 0.930g / cm3, and the ethylene-propylene block copolymer has a melt index of 18g / 10min (230°C, 2.16kg). The lubricant blend is a mixture of polyethylene wax and zinc stearate in a mass ratio of 2:1, and the antioxidant is a mixture of commercially available BASF 168 and 1010 in a mass ratio of 1:1.

[0042] The preparation method of the matt masterbatch for BOPP matt film described in this embodiment is as follows:

[0043] The raw materials were weighed according to the weight percentage ratio, and copolymerized polypropylene, high-density polyethylene, low-density linear polyethylene, ethylene-propylene copolymer, lubricant and antioxidant were first mixed at a low speed for 3 minutes in a high-speed mixer, and then mixed at a high speed for 1 minute. The mixture was then sucked into the hopper of a twin-screw extruder by a suction machine, extruded into granules at 230°C, and dried.

[0044] Example 6

[0045] The matting material for BOPP matting film of this embodiment contains 50% copolymerized polypropylene, 50% high-density polyethylene, 0.6% lubricant blend, and 0.1% antioxidant by weight percentage. The copolymerized polypropylene is specifically a terpolymer with a melt index of 7.5g / 10min (230°C, 2.16kg), and the high-density polyethylene has a melt index of 0.1g / 10min (190°C, 2.16kg) and a density of 0.960g / cm3. The lubricant blend is a mixture of polyethylene wax and zinc stearate in a mass ratio of 2:1, and the antioxidant is a commercially available BASF 168 and 1010 compounded in a mass ratio of 2:1.

[0046] The preparation method of the matt masterbatch for BOPP matt film described in this embodiment is as follows:

[0047] The raw materials were weighed according to the weight percentage ratio, and copolymerized polypropylene, high-density polyethylene, low-density linear polyethylene, ethylene-propylene copolymer, lubricant and antioxidant were first mixed at a low speed for 3 minutes in a high-speed mixer, and then mixed at a high speed for 1 minute. The mixture was then sucked into the hopper of a twin-screw extruder by a suction machine, extruded into granules at 230°C, and dried.

[0048] The BOPP matte film of the present invention comprises a matte layer 1, a core layer 2 and a glossy layer 3; wherein the matte layer 1 contains 100% polyolefin matte material; the core layer 2 contains 97wt% homopolypropylene and 2wt% antistatic agent masterbatch; the glossy layer 3 contains 97wt% homopolypropylene and 2wt% anti-sticking agent. The thickness of each layer is: the matte layer 1 is 1.4μm; the core layer 2 is 10-18μm; the glossy layer 3 is 1μm. The BOPP matte film is biaxially stretched in a BOPP production line with a width of 8.7m, the matte surface is roughened, and finally shaped and rolled into a film.

[0049] The BOPP matte materials prepared in Examples 1-5 were respectively used as the polyolefin matte materials of the matte layer of the BOPP matte film, and BOPP matte films were respectively prepared according to the above-mentioned layer structures and preparation methods.

[0050] Preferably, the matte layer has a thickness of 1.7 μm.

[0051] Comparative Example 1

[0052] In this comparative example, the BOPP matte film includes a matte layer 1, a core layer 2 and a glossy layer 3; wherein the matte layer 1 contains 100% polyolefin matte material; the core layer 2 contains 97wt% homopolypropylene and 2wt% antistatic agent masterbatch; the glossy layer 3 contains 97wt% homopolypropylene and 2wt% anti-sticking agent. The thickness of each layer is: the matte layer 1 is 1.4μm; the core layer 2 is 10μm; the glossy layer 3 is 1μm. The BOPP matte film is biaxially stretched in a BOPP production line with a width of 8.7m, the matte surface is roughened, and finally shaped and rolled into film.

[0053] The polyolefin matt masterbatch used in the matt layer in this comparative example is the matt masterbatch prepared in Example 6.

[0054] Preferably, the thickness of the small optical layer is 1.7 μm.

[0055] Comparative Example 2

[0056] In this comparative example, the BOPP matte film includes a matte layer 1, a core layer 2 and a glossy layer 3; wherein the matte layer 1 contains 100% polyolefin matte material; the core layer 2 contains 98wt% homopolypropylene and 3wt% antistatic agent masterbatch; the glossy layer 3 contains 98wt% homopolypropylene and 3wt% anti-sticking agent. The thickness of each layer is: the matte layer 1 is 2.5μm; the core layer 2 is 18μm; the glossy layer 3 is 1.5μm. The BOPP matte film is biaxially stretched in a BOPP production line with a width of 8.7m, the matte surface is roughened, and finally shaped and rolled into film.

[0057] The polyolefin matt masterbatch used in the matt layer in this comparative example is a commercially available matt material.

[0058] Preferably, the thickness of the small optical layer is 1.7 μm.

[0059] Example 7

[0060] In this embodiment, the matt film prepared from the matt masterbatch of Examples 1-5 and the matt layer of the BOPP matt film of Comparative Example 1 were tested for haze and gloss, wherein the test point selection method is: starting from the BOPP line drive side, 5 points are taken from left to right to test the haze and gloss. The haze test is performed in accordance with GB / T2410-2008, and the matt surface faces the light source. In order to better show that the matt material produced by the present invention improves the matt uniformity of the BOPP matt film, the test data is measured by standard deviation. The lower the standard deviation value, the smaller the difference between the test points, the better the matt uniformity and thickness uniformity, and the matt layer thickness test is based on the national standard GB / T 38518-2020.

[0061]

[0062] As can be seen from the above table, the BOPP matte film prepared from the matte material of the present invention is better in matte layer thickness and matte uniformity than Comparative Example 2 (BOPP matte film prepared from commercially available matte material) and Comparative Example 1 (matt film prepared from matt material without adding low-density linear polyethylene and ethylene-propylene copolymer).

[0063] 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.

[0064] 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 matting material for BOPP matting film, characterized in that: The invention comprises the following raw materials in percentage by weight: 40% to 50% copolymerized polypropylene, 5% to 10% LLDPE, 2% to 7% ethylene-propylene block copolymer and 0.3% to 0.6% lubricant blend; the ethylene content in the ethylene-propylene block copolymer is 40%; the lubricant blend comprises polyethylene wax, and the lubricant blend further comprises any one of calcium stearate and zinc stearate.

2. The matting material for BOPP matting film according to claim 1, characterized in that: It also includes 40% to 50% HDPE by mass; the density of the HDPE is 0.945-0.960 g / cm3.

3. The matting material for BOPP matting film according to claim 1, characterized in that: The invention also includes an antioxidant with a mass percentage of 0.1% to 0.3%, wherein the antioxidant includes a blend of antioxidant 1010 and antioxidant 168.

4. The matting material for BOPP matting film according to claim 3, characterized in that: The mass ratio of the antioxidant 1010 to the antioxidant 168 is 1:

1.

5. The matting material for BOPP matting film according to claim 1, characterized in that: The copolymerized polypropylene includes one or more of a binary copolymer and a ternary copolymer.

6. The matting material for BOPP matting film according to claim 1, characterized in that: The mass ratio of the polyethylene wax to calcium stearate or to zinc stearate is 1:1-3:

1.

7. The matting material for BOPP matting film according to claim 1, characterized in that: The density of the LLDPE is 0.924-0.940 g / cm3.

8. A method for preparing a matting material for BOPP matting film, characterized in that: The following steps are involved: The raw material copolymer polypropylene 40%-50%, HDPE 40%-50%, LLDPE 5%-10%, ethylene-propylene block copolymer 2%-7%, lubricant blend 0.3%-0.6% and antioxidant 0.1%-0.3% are mixed in mass percentage, extruded and granulated to obtain matte material for BOPP matte film.

9. The method for preparing the matting material for BOPP matting film according to claim 8, characterized in that: The extrusion temperature is 225-235°C.

10. Use of the matte material according to any one of claims 1 to 7 or the matte material prepared by the preparation method according to any one of claims 8 to 9 in the production of BOPP matte film.

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