WO2023004971A1

WO2023004971A1 - Ultralow-temperature heat-seal wear-resistant bopp thin film and preparation method therefor

Info

Publication number: WO2023004971A1
Application number: PCT/CN2021/120202
Authority: WO
Inventors: 王俊峰; 黎坛; 杜秀亮; 殷儒鸿; 刘海英
Original assignee: 海南赛诺实业有限公司
Priority date: 2021-07-29
Filing date: 2021-09-24
Publication date: 2023-02-02
Also published as: CN113580705A; CN113580705B

Abstract

An ultralow-temperature heat-seal wear-resistant BOPP thin film, comprising an upper-layer structure, a middle-layer structure and a lower-layer structure which are arranged in sequence. The raw materials for forming the upper-layer structure comprise: a first low-temperature heat-seal metallocene, a first polydimethylsiloxane, a silicone masterbatch, a first anti-blocking agent, and a first copolymer. The raw materials for forming the middle-layer structure comprise: homo-polypropylene, petroleum resin and an antistatic agent. The raw materials for forming the lower-layer structure comprise: a second low-temperature heat-seal metallocene, a second polydimethylsiloxane, a second anti-blocking agent, and a second copolymer. The BOPP thin film has wear resistance and an ultralow heat-seal temperature.

Description

A kind of ultra-low temperature heat-sealing wear-resistant BOPP film and preparation method thereof

This application claims the priority of the Chinese patent application submitted to the China Patent Office on July 29, 2021, with the application number 202110862964.7 and the title of the invention "An ultra-low temperature heat-sealable wear-resistant BOPP film and its preparation method", the entire content of which Incorporated in this application by reference.

technical field

The invention belongs to the technical field of polymer materials, and in particular relates to an ultra-low temperature heat-sealable wear-resistant BOPP film and a preparation method thereof.

Background technique

The existing cosmetics on the market, especially the packaging boxes of high-end cosmetics, are compounded with a layer of film (mostly PE film). The temperature will cause the BOPP film and the PE film compounded in the packaging box to stick together, which will damage the aesthetics of the product. At the same time, the packaging of high-end cosmetics is in contact with external substances in the logistics link and terminal sales link, and the packaging is prone to scratches, which greatly reduces the grade of the product. , so higher requirements are placed on the wear resistance of the packaging.

In order to solve this sticking problem in the application market, coating films (mainly acrylic coating films) are usually used to replace conventional heat-sealable BOPP films, but on the one hand, the cost of coating films is at least 60% higher than that of heat-sealable BOPP films. %, on the other hand, the acrylic coated film is much worse than the heat-sealed BOPP film in terms of wear resistance and haze.

From the perspective of wear resistance, the existing wear-resistant BOPP film mainly achieves the purpose of improving the wear resistance of the film through the addition of polymer silicone smooth masterbatch and inorganic nano-materials. The disadvantages are: 1) poor wear resistance Generally, the wear resistance index is greater than 0.5%; 2) The added nano-scale substances are inorganic substances that will affect the optical properties (gloss and haze) of the film, the amount is not well controlled, and the film may even produce appearance defects (crystal points); 3) Inorganic nano-scale substances are prone to agglomeration, and there are defects on the appearance of the film.

From the perspective of anti-adhesion, coating films (acrylic or PVDC coated on the surface of the substrate film) are often used to prevent adhesion to the PE film compounded on the packaging box when the soldering iron is heated. Poor, largely unable to present the design concept of the product.

Contents of the invention

In view of this, the technical problem to be solved by the present invention is to provide an ultra-low temperature heat-sealable wear-resistant BOPP film and a preparation method thereof.

The invention provides an ultra-low temperature heat-sealable wear-resistant BOPP film, which comprises an upper layer structure, a middle layer structure and a lower layer structure arranged in sequence;

The raw materials for forming the upper structure include: the first low-temperature heat-sealable metallocene, the first polydimethylsiloxane, silicone masterbatch, the first anti-blocking agent and the first copolymer; the first low-temperature heat-sealable The mass ratio of the permanent metallocene, the first polydimethylsiloxane, the silicone polymer material, the first anti-blocking agent and the first copolymer is (35-43): (5-10): (8- 15): (0.5～2): (35～43);

The raw materials forming the middle layer structure include: homopolypropylene, petroleum resin and antistatic agent; the mass ratio of homopolypropylene, petroleum resin and antistatic agent is (61.5～98.5):(0～35):(1.5 ~3.5);

The raw materials for forming the lower structure include: the second low-temperature heat-sealable metallocene, the second polydimethylsiloxane, the second anti-blocking agent and the second copolymer; the second low-temperature heat-sealable metallocene, the second The mass ratio of polydimethylsiloxane, the second anti-blocking agent and the second copolymer is (45-50): (0-10): (0.5-2): (40-50);

The first copolymer and the second copolymer are each independently selected from ethylene-propylene-butadiene terpolymers and/or ethylene-propylene binary copolymers.

Preferably, the ultra-low temperature heat-sealable wear-resistant BOPP film has a thickness of 18-50 μm;

The thickness of the superstructure is 0.5-1.0 μm;

The thickness of the middle layer structure is 16-48.8 μm;

The thickness of the lower layer structure is 0.7-1 μm.

Preferably, the first low-temperature heat-sealable metallocene and the second low-temperature heat-sealable metallocene are each independently selected from Sumitomo SP7731 and/or Basel Adsyl 7410XCP;

The molecular weights of the first polydimethylsiloxane and the second polydimethylsiloxane are independently 10,000 to 30,000;

The silicone masterbatch is a smooth masterbatch, and the carrier is polypropylene; the molecular weight of silicone in the silicone masterbatch is greater than 200,000; the effective content of silicone in the silicone masterbatch is 10% to 15% %;

The first anti-blocking agent and the second anti-blocking agent are independently selected from organic anti-blocking agents; the particle size of the organic anti-blocking agent is 2-4 μm;

The molecular weight of the homopolypropylene is 200,000 to 450,000; the melt index of the homopolypropylene is 2g/min to 4g/10min (230°C, 2.16Kg);

The petroleum resin is selected from C3 petroleum resin and/or C5 petroleum resin;

The antistatic agent is selected from polyamide antistatic agents;

The molecular weights of the first copolymer and the second copolymer are independently 30,000 to 70,000;

The molar ratio of ethylene monomer units, propylene monomer units and butadiene monomer units in the ethylene-propylene-butadiene terpolymer is 50:(20-40):(50-70);

The molar ratio of ethylene monomer units to propylene monomer units in the ethylene-propylene binary copolymer is (40-60):(40-60).

Preferably, the silicone masterbatch is selected from one or more of silicone masterbatches whose brands are IL2580SC, SAB06554PPR and Taiwan Kenhua PSE99RP;

The first anti-blocking agent and the second anti-blocking agent are each independently selected from the product of Schulman Company brand ABVT22SC and/or Japanese HIS04S;

The petroleum resin is selected from Jiangyin Jingliang's FS600A, the products of Beijing Duchen New Materials Co., Ltd. whose trademarks are PPMA66 and PPMA66H, the products of Hainan Mulong New Materials Co., Ltd. whose trademarks are ML8002 and Hainan Heli's HL8139. or more;

The antistatic agent is selected from one or more of the products of Beijing Duchen New Materials Co., Ltd. with the brand name of DS126T, Schulman's FASPA2955 and Suzhou Constamp Engineering Plastics Co., Ltd.'s product with the brand name of AT4023PP.

Preferably, the molecular weight of the first polydimethylsiloxane and the second polydimethylsiloxane is 20,000;

The melt index of the homopolypropylene is 3g/10min (230°C, 2.16Kg);

The molecular weight of the first copolymer and the second copolymer is 45,000 to 55,000;

The molar ratio of ethylene monomer units, propylene monomer units and butadiene monomer units in the ethylene-propylene-butadiene terpolymer is 50:34:62;

The present invention also provides a method for preparing the above-mentioned ultra-low temperature heat-sealable wear-resistant BOPP film, comprising:

Ultra-low temperature heat-sealable wear-resistant BOPP film is obtained by co-extruding, casting, longitudinal stretching and transverse stretching of the raw materials of the upper layer structure, the middle layer structure and the lower layer structure.

Preferably, during the co-extrusion process, the extrusion temperature of the raw materials of the upper structure is 180°C to 225°C; the extrusion temperature of the raw materials of the middle structure is 235°C to 260°C; the extrusion temperature of the raw materials of the lower structure is 180°C to 220°C .

Preferably, the temperature of the cast sheet is 18°C to 32°C.

Preferably, preheating is carried out before the longitudinal stretching; the temperature of the preheating is 105°C to 115°C; the temperature of the longitudinal stretching is 60°C to 70°C; the setting temperature of the longitudinal stretching is 72°C ~80°C; the ratio of longitudinal stretching is 450%~620%.

Preferably, preheating is carried out before the transverse stretching; the temperature of the preheating is 168°C-178°C; the temperature of the transverse stretching is 148°C-165°C; the setting temperature of the transverse stretching is 105°C ~165°C; the ratio of transverse stretching is 800%~1000%.

The invention provides an ultra-low temperature heat-sealable wear-resistant BOPP film, which includes an upper structure, a middle structure and a lower structure arranged in sequence; the raw materials for forming the upper structure include: the first low-temperature heat-sealable metallocene, the first polydimethyl Siloxane, silicone masterbatch, first anti-blocking agent and first copolymer; the first low-temperature heat-sealable metallocene, the first polydimethylsiloxane, silicone polymer material, the first The mass ratio of the primary anti-blocking agent to the first copolymer is (35-43): (5-10): (8-15): (0.5-2): (35-43); the raw materials for forming the middle layer structure include: Homopolypropylene, petroleum resin and antistatic agent; the mass ratio of said homopolypropylene, petroleum resin and antistatic agent is (61.5～98.5): (0～35): (1.5～3.5); form the lower layer structure The raw materials include: the second low-temperature heat-sealable metallocene, the second polydimethylsiloxane, the second anti-blocking agent and the second copolymer; the second low-temperature heat-sealable metallocene, the second polydimethylsiloxane The mass ratio of base siloxane, the second anti-blocking agent and the second copolymer is (45-50): (0-10): (0.5-2): (40-50); the first copolymer and The second copolymers are each independently selected from ethylene-propylene-butadiene terpolymers and/or ethylene-propylene binary copolymers. Compared with the prior art, the present invention reduces the shear force during friction on the surface of the BOPP film and increases the The lubricating effect can also reduce the surface tension, achieve a lower friction coefficient, and improve the wear resistance of the film; at the same time, a low-temperature heat-sealable metallocene is added to the surface layer to reduce the heat-sealing temperature of the BOPP film.

Experiments have shown that the heat-sealing film on the surface layer of the present invention uses a low-temperature heat-sealable metallocene with a sealing temperature of 75°C, and the temperature of the soldering iron is set at 80°C during heat-sealing to ensure that the heat-sealing strength of the film reaches 2.5N/15mm and at the same time it is compatible with the packaging The PE film compounded on the box will not be stuck; the BOPP film provided by the invention adopts low-temperature heat-sealable metallocene to ensure that the heat-sealing strength can reach 2.5N/15mm at around 80°C, and does not use the addition of inorganic nano-materials. The method makes the wear resistance of the product reach ≤0.2%, and the optical performance of the prepared film product is excellent.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The thickness of the ultra-low temperature heat-seal wear-resistant BOPP film provided by the present invention is preferably 18-50 μm, more preferably 18-40 μm; in the examples provided by the present invention, the thickness of the ultra-low temperature heat-seal wear-resistant BOPP film is specifically 18μm, 22μm or 40μm.

The ultra-low temperature heat-seal wear-resistant BOPP film includes an upper structure, a middle structure and a lower structure arranged in sequence; wherein the upper structure and the lower structure are functional layers, the upper structure provides ultra-high wear resistance and low-temperature heat sealing performance, and the lower structure provides Low-temperature heat-sealed structure, the middle layer structure is the base layer of the film to provide the basic structure for the film.

In the present invention, the thickness of the superstructure is preferably 0.5-1.0 μm, more preferably 0.5-0.7 μm; in the embodiments provided by the invention, the thickness of the superstructure is specifically 0.5 μm, 0.6 μm or 0.7 μm; The upper layer structure is at least 0.5 μm to ensure heat sealing strength and wear resistance; the raw materials forming the upper layer structure include: the first low-temperature heat-sealable metallocene, the first polydimethylsiloxane, silicone masterbatch , the first anti-blocking agent and the first copolymer; the first low-temperature heat-sealable metallocene is preferably Japanese Sumitomo SP7731 and/or Basel Adsyl 7410XCP; the molecular weight of the first polydimethylsiloxane is preferably 10,000 to 30,000, more preferably 15,000 to 25,000, and more preferably 20,000; the silicone masterbatch is a smooth masterbatch, and its carrier is preferably polypropylene; the amount of silicone in the silicone masterbatch The molecular weight is preferably greater than 200,000; the effective content of silicone in the silicone masterbatch is preferably 10% to 15%; in the present invention, the silicone masterbatch is most preferably IL2580SC, SAB06554PPR and Taiwan Ken One or more in the silicone masterbatch of ELPSE99RP; The first anti-blocking agent is preferably an organic anti-blocking agent, which has certain elasticity; The first anti-blocking agent is preferably elastic microbeads Its particle size is preferably 2～4 μm, more preferably 3 μm; In the present invention, the first anti-blocking agent is most preferably the product of Schulman company brand ABVT22SC and/or Japanese HIS04S; the first The molecular weight of the copolymer is preferably 30,000 to 70,000, more preferably 30,000 to 60,000, and more preferably 30,000 to 50,000; the first copolymer is propylene-ethylene-butadiene terpolymer and/or ethylene-propylene meta-copolymer; wherein, the molar ratio of propylene monomer unit, ethylene monomer unit and butadiene monomer unit in the propylene-ethylene-butadiene terpolymer is preferably (1.5～3): (0.5～ 1.5): (0.5-1.5), more preferably (2-2.5): (0.8-1.2): (0.8-1.2), more preferably 2:1:1; ethylene in the ethylene-propylene binary copolymer The molar ratio of monomer units to propylene monomer units is preferably (1-3):1, more preferably (1.5-2.5):1, and more preferably 2:1; the first low-temperature heat-sealable metallocene, The mass ratio of the first polydimethylsiloxane, the silicone polymer material, the first anti-blocking agent and the first copolymer is preferably (35-43): (5-10): (8-15): (0.5～2): (35～43), more preferably (35-40): (7～10): (8～13): (0.5～2): (37～43), more preferably (35 -40): (8～10): (8～12): (0.5～2): (38～42), most preferably (38～40): (8～9): (8～12): 2 : (36～40); In the embodiment provided by the present invention, the first low-temperature heat-sealable metallocene, the first polydimethylsiloxane The mass ratio of alkane, silicone polymer material, first anti-blocking agent and first copolymer is specifically 40:8:10:2:40, 38:10:12:2:38 or 45:9:8: 2:36. The property that the polymer chain can change its conformation is called flexibility. The main chain structure has a significant impact on the flexibility of the polymer. The Si-O-Si bond angle in the main chain structure of polydimethylsiloxane is large. The bonds of Si-O are long and internal rotation is relatively easy, so it has good flexibility. The invention obtains a functional material with improved wear resistance by blending and modifying polydimethylsiloxane and ethylene-propylene-butadiene terpolymer or ethylene-propylene binary copolymer, and then provides BOPP abrasion resistance of the film.

According to the present invention, the thickness of the middle layer structure is preferably 16-48.8 μm; in the embodiment provided by the invention, the thickness of the middle layer structure is specifically 16.6 μm, 20.7 μm or 38.5 μm; the raw materials for forming the middle layer structure include homopolymer Propylene, petroleum resin and antistatic agent; the molecular weight of the homopolypropylene is preferably 200,000 to 450,000, more preferably 250,000 to 400,000, more preferably 300,000 to 350,000, most preferably 310,000 to 330,000; The melt index of homopolypropylene is preferably 2g/min～4g/10min (230°C, 2.16Kg), more preferably 2.5g/min～3.5g/10min (230°C, 2.16Kg), and more preferably 3g/10min (230 DEG C, 2.16Kg); The petroleum resin is preferably C3 petroleum resin and/or C5 petroleum resin, more preferably Jiangyin's excellent FS600A, the product of Beijing Duchen New Material Co., Ltd. brand name PPMA66, PPMA66H, Hainan Mu One or more of the product of Longxin Materials Co., Ltd. whose brand name is ML8002 and HL8139 of Hainan Heli; the antistatic agent is preferably a polyamide antistatic agent, more preferably glyceryl monostearate and ethyl alcohol The compound of oxyamine is preferably one or more of the product of Beijing Duchen New Material Co., Ltd. with the brand name of DS126T, Schulman's FASPA2955 and Suzhou Constamp Engineering Plastics Co., Ltd.'s product of AT4023PP Kind; The mass ratio of described homopolypropylene, petroleum resin and antistatic agent is preferably (61.5～98.5): (0～35): (1.5～3.5); More preferably (65～95): (5～ 35): (1.5-3.5), more preferably (65-90): (10-35): (1.5-3.5), more preferably (65-85): (15-35): (1.5-3.5) , more preferably (65～80): (15～30): (1.5～3.5), most preferably (67～78): (15～30): (2～3); in the embodiment provided by the present invention Among them, the mass ratio of the homopolypropylene, petroleum resin and antistatic agent is specifically 78:20:2, 73:15:2 or 67:30:3.

According to the present invention, the thickness of the lower structure is preferably 0.7-1 μm; in the embodiment provided by the present invention, the thickness of the lower structure is specifically 0.8 μm. The raw materials for forming the lower structure include the second low-temperature heat-sealable metallocene, the second polydimethylsiloxane, the second anti-blocking agent and the second copolymer; the second low-temperature heat-sealable metallocene is preferably Japanese Sumitomo SP7731 and/or Basel Adsyl 7410XCP; the molecular weight of the second polydimethylsiloxane is preferably 10,000 to 30,000, more preferably 15,000 to 25,000, and more preferably 20,000; the second antiblocking agent It is preferably an organic anti-blocking agent, which has certain elasticity; the second anti-blocking agent is preferably elastic microbeads; its particle size is preferably 2 to 4 μm, more preferably 3 μm; in the present invention, the second anti-blocking agent The most preferred secondary anti-blocking agent is the product of ABVT22SC from Schulman Company and/or Japanese HIS04S; the molecular weight of the second copolymer is preferably 3 to 70,000, more preferably 4 to 60,000, and more preferably 5 ten thousand; the second copolymer is propylene-ethylene-butadiene terpolymer and/or ethylene-propylene binary copolymer; wherein, in the propylene-ethylene-butadiene terpolymer, the propylene monomer unit, The molar ratio of ethylene monomer units to butadiene monomer units is preferably 5 (1.5-3): (0.5-1.5): (0.5-1.5), more preferably (2-2.5): (0.8-1.2): (0.8~1.2), preferably 2:1:1; the molar ratio of ethylene monomer units to propylene monomer units in the ethylene-propylene binary copolymer is preferably (1~3):1, more preferably (1.5-2.5): 1, more preferably 2:1; the mass ratio of the second low-temperature heat-sealable metallocene, the second polydimethylsiloxane, the second anti-blocking agent to the second copolymer is preferably (45～50): (0～10): (0.5～2): (40～50), more preferably (45～50): (0～8): (0.5～2): (40～48 ), more preferably (48～50): (0～5): (0.5～2): (45～48); in the embodiment provided by the present invention, the second low temperature heat-sealable metallocene, the second The mass ratio of dipolydimethylsiloxane, the second anti-blocking agent and the second copolymer is specifically 48:5:2:45, 50:0:2:48 or 50:2:2:46.

In the present invention, by adding additives with high symmetry and flexible molecular chain structure to the surface layer of the BOPP film, the shear force during friction on the surface of the BOPP film can be reduced, the lubricating effect can be increased, and the surface can also be reduced. Tension, to achieve a lower coefficient of friction, improve the wear resistance of the film; at the same time, a low-temperature heat-sealable metallocene is added to the surface layer, which reduces the heat-sealing temperature of the BOPP film.

The present invention also provides a method for preparing the above-mentioned ultra-low temperature heat-sealable wear-resistant BOPP film, which includes: co-extruding the raw materials of the upper structure, the raw materials of the middle structure and the raw materials of the lower structure, casting, longitudinal stretching and transverse After stretching, an ultra-low temperature heat-sealable wear-resistant BOPP film is obtained.

Among them, the present invention has no special limitation on the sources of all raw materials, which can be commercially available. The raw materials of the upper structure, the middle structure and the lower structure are the same as above, and will not be repeated here.

In the present invention, it is preferable to mix the raw materials of each layer, and then enter the respective extruders for extrusion, and then converge and flow out at the die head to realize co-extrusion; wherein, the extrusion temperature of the raw materials of the upper structure is preferably 180°C to 225°C °C, more preferably 200 °C to 225 °C, more preferably 220 °C to 225 °C; the extrusion temperature of the raw material of the middle layer structure is preferably 235 °C to 260 °C, more preferably 240 °C to 255 °C, and more preferably 240 °C to 250°C; the extrusion temperature of the raw material of the lower structure is preferably 180°C-220°C, more preferably 190°C-220°C, more preferably 200°C-220°C, most preferably 210°C-215°C.

After co-extrusion, the sheet is cast to obtain a sheet; the temperature of the cast sheet is preferably 18°C to 32°C, more preferably 18°C to 30°C, more preferably 18°C to 25°C, most preferably 18°C to 22°C; the time is preferably 1-5s, more preferably 2s.

The sheet obtained by casting is stretched longitudinally; the polymer molecules are longitudinally oriented by stretching longitudinally. In the present invention, it is preferred to perform preheating first and then longitudinal stretching; the preheating temperature is preferably 105°C to 115°C; in the examples provided by the present invention, the preheating temperature is specifically 105°C , 112°C or 115°C; the preheating time is preferably 5-20s, more preferably 8-15s, and more preferably 10s; the longitudinal stretching temperature is preferably 60°C-70°C, more preferably 65 ℃～70℃, more preferably 67℃～68℃; the rate of longitudinal stretching is preferably 150～200m/min, more preferably 160～200m/min, and more preferably 180m/min; the setting temperature of longitudinal stretching is preferably It is 72°C to 80°C, more preferably 74°C to 80°C, and more preferably 75°C to 77°C; the ratio of longitudinal stretching is preferably 450% to 620%, more preferably 500% to 620%, and more preferably 550% to 620%, most preferably 560% to 600%.

The longitudinally stretched sheet is stretched transversely to orient the polymer molecules in the transverse direction; in the present invention, it is preferred to preheat first and then transversely stretch; the preheating temperature is preferably 168°C to 178°C , more preferably 170°C to 178°C, more preferably 172°C to 176°C; in the examples provided by the present invention, the preheating temperature is specifically 172°C, 173°C or 176°C; the preheating temperature The time is preferably 2 to 5s, more preferably 3s; the transverse stretching is preferably stretched in a stretching zone with a certain expansion angle; the expansion angle is preferably 25°; the temperature of the transverse stretching is preferably 148 °C to 165 °C, more preferably 150 °C to 162 °C, more preferably 154 °C to 160 °C; in the examples provided by the present invention, the temperature of the transverse stretching is specifically 154 °C, 156 °C or 160 °C; The rate of transverse stretching is preferably 150 to 200m/min, more preferably 160 to 200m/min, and more preferably 185m/min; the setting temperature of transverse stretching is preferably 105°C to 165°C, more preferably 110°C to 160°C °C, more preferably 120°C to 150°C, most preferably 125°C to 140°C; in the embodiments provided by the present invention, the setting temperature of the transverse stretching is specifically 125°C, 130°C or 140°C; the transverse stretching The stretching ratio is preferably 800% to 1000%, more preferably 830% to 900%, and still more preferably 850% to 880%.

After transverse stretching, surface treatment may or may not be carried out as required. Finally, the film is flattened by a flattening roller in the traction area, and wound up to obtain an ultra-low temperature heat-sealable and wear-resistant BOPP film.

In order to further illustrate the present invention, an ultra-low temperature heat-sealable wear-resistant BOPP film provided by the present invention and its preparation method are described in detail below in conjunction with examples.

The reagents used in the following examples are all commercially available.

Example 1

The ultra-low temperature heat-sealable wear-resistant BOPP film of this embodiment is divided into three layers of upper layer, middle layer and lower layer, with a total thickness of 18 μm. The thickness of the upper layer is 0.6 μm, and it is prepared from the following raw materials in weight ratio: 40% metallocene low-temperature heat-sealing functional masterbatch (SP7331 from Japan, with a sealing temperature of 70°C), 40% propylene-ethylene polymer (molecular weight: 5 10,000, the molar ratio of the two is 2:1), 10% silicone polymer (more than 500,000 molecular weight), 8% polydimethylsiloxane (20,000 molecular weight), 2% anti-blocking agent (glass The microbead diameter is 4 μm); the thickness of the middle layer is 16.6 μm, which is formulated with the following raw materials in weight ratio: 78% homopolypropylene (molecular weight is about 320,000, and the melt index is 3g/10min (230°C, 2.16Kg)), 20% petroleum resin (C5), 2% antistatic agent (composite of glyceryl monostearate and ethoxylated amine); the thickness of the lower layer is 0.8 μm, and is formulated by the raw materials of the following weight ratio: 48 %Metallocene low-temperature heat-sealing masterbatch (Japan's SP7331 has a sealing temperature of 90°C), 45% propylene-ethylene-butadiene copolymer (molecular weight is 30,000, and the molar ratio of the three is 2:1:1), 5 % of polydimethylsiloxane (molecular weight 20,000), 2% of anti-blocking agent (glass beads, diameter 4 μm).

The manufacture method of the above-mentioned ultra-low temperature heat-seal wear-resistant BOPP film is as follows:

(1) Ingredients

The upper, middle and lower layers are mixed according to the raw materials in the above weight ratio, and the mixing can be done manually or by equipment.

(2) extrusion

The three layers of raw materials flow into their respective extruders after being mixed, and then converge and flow out at the die head after extrusion. The temperature of the upper layer extruder is 220°C, the temperature of the middle layer extruder is 245°C, and the temperature of the lower layer extruder is 215°C.

(3) cast sheet

The resin flowing out of the die is cooled into a sheet by a casting machine, the cooling temperature is 22° C., and the cooling time is 2 seconds.

(4) Longitudinal stretch

Preheat the sheet at 105°C for 10 seconds, and then stretch the sheet longitudinally at a certain speed (line speed 180m/min), so that the polymer molecules are longitudinally oriented. The stretching temperature is 68°C, and the setting temperature It was 75°C, and the draw ratio was 600%.

(5) Lateral stretching

The sheet after longitudinal stretching is preheated at 172°C for 3 seconds, and then stretched transversely in the stretching zone with a certain expansion angle (25°) through the set chain guide rail, so that the polymer molecules are oriented in the transverse direction , the stretching rate is 185m/min, the stretching temperature is 154°C, the setting temperature is 125°C, and the stretching ratio is 850%.

(6) Corona treatment

No need for corona treatment

(7) Winding

The film is flattened by the flattening roller in the traction area, and finally wound up by the winding machine.

Example 2

The ultra-low temperature heat-sealable wear-resistant BOPP film of this embodiment is divided into three layers of upper layer, middle layer and lower layer, with a total thickness of 22 μm. The thickness of the upper layer is 0.5 μm, and it is prepared from the following raw materials in weight ratio: 38% metallocene low-temperature heat-sealing functional masterbatch (SP7731 from Japan with a sealing temperature of 70°C), 38% propylene-ethylene-butadiene copolymer ( The molecular weight is 30,000, and the molar ratio of the three is 2:1:1), 12% silicone polymer (more than 500,000 molecular weight), 10% polydimethylsiloxane (20,000 molecular weight), 2% anti Adhesive agent (glass microbead diameter 4 μm); The thickness of the middle layer is 20.7 μm, which is formulated with the raw materials of the following weight ratio: 73% homopolypropylene (molecular weight is about 320,000, and the melt index is 3g/10min (230°C, 2.16Kg)), 15% petroleum resin (C5), 2% antistatic agent (composite of glyceryl monostearate and ethoxylated amine); the thickness of the lower layer is 0.8 μm, by the following weight ratio The raw materials are prepared as follows: 50% metallocene low-temperature heat-sealing functional masterbatch (Japanese SP7731, sealing temperature 90°C), 48% propylene-ethylene-butadiene copolymer (molecular weight is 30,000, and the molar ratio of the three is 2: 1:1), 2% anti-blocking agent (glass bead size 4μm).

(1) Ingredients

(2) extrusion

The three layers of raw materials are mixed and flow into their respective extruders. After extrusion, they converge and flow out at the die head. The temperature of the upper layer extruder is 225°C, the temperature of the middle layer extruder is 250°C, and the temperature of the lower layer extruder is 210°C.

(3) cast sheet

The resin flowing out of the die is cooled into a sheet by a casting machine, the cooling temperature is 20°C, and the cooling time is 2s.

(4) Longitudinal stretch

Preheat the sheet at 112°C for 10s and then stretch the sheet longitudinally at a certain speed (180m/min) to orient the polymer molecules longitudinally. The stretching temperature is 67°C and the setting temperature is 77°C. The draw ratio was 580%.

(5) Lateral stretching

The sheet after longitudinal stretching is preheated at 173°C for 4s, and then stretched transversely in the stretching zone with a certain expansion angle (25°) through the set chain guide rail, so that the polymer molecules are oriented in the transverse direction, The stretching rate was 185m/min, the stretching temperature was 156°C, the setting temperature was 130°C, and the stretching ratio was 880%.

(6) Corona treatment

No need for corona treatment

(7) Winding

Example 3

The ultra-low temperature heat-sealable wear-resistant BOPP film of this embodiment is divided into three layers of upper layer, middle layer and lower layer, with a total thickness of 40 μm. The thickness of the upper layer is 0.7 μm, and it is prepared from the following raw materials in weight ratio: 45% metallocene low-temperature heat-sealing functional masterbatch (SP7731 from Japan, sealing temperature 70°C), 36% ethylene-propylene copolymer (molecular weight: 5 10,000, the molar ratio of the two is 2:1), 8% silicone polymer (more than 500,000 molecular weight), 9% polydimethylsiloxane (20,000 molecular weight), 2% anti-blocking agent (glass micro bead size 4 μm); the thickness of the middle layer is 38.5 μm, which is formulated with the following raw materials in weight ratio: 67% homopolypropylene (molecular weight is about 320,000, and the melt index is 3g/10min (230°C, 2.16Kg)), 30% petroleum resin (C5), 3% antistatic agent (composite of glyceryl monostearate and ethoxylated amine); the thickness of the lower layer is 0.8 μm, and is formulated by the raw materials of the following weight ratio: 50 %Metallocene low-temperature heat-sealing functional masterbatch (SP7731 from Japan, sealing temperature 90°C), 46% ethylene-propylene copolymer (molecular weight is 50,000, the molar ratio of the two is 2:1), 2% poly Methyl siloxane (molecular weight: 20,000), 2% anti-blocking agent (glass bead diameter: 4 μm).

(1) Ingredients

(2) extrusion

The three layers of raw materials are mixed and flow into their respective extruders. After extrusion, they converge and flow out at the die head. The temperature of the upper layer extruder is 220°C, the temperature of the middle layer extruder is 240°C, and the temperature of the lower layer extruder is 215°C.

(3) cast sheet

The resin flowing out of the die is cooled into a sheet by a casting machine, the cooling temperature is 18°C, and the cooling time is 2s.

(4) Longitudinal stretch

Preheat the sheet at 115°C for 10 seconds, and then stretch the sheet longitudinally at a certain speed (180m/min) to orient the polymer molecules longitudinally. The stretching temperature is 68°C and the setting temperature is 75°C. , and the stretch ratio is 560%.

(5) Lateral stretching

The sheet after longitudinal stretching is preheated at 176°C for 5s, and then stretched transversely in the stretching zone with a certain expansion angle (25°) through the set chain guide rail, so that the polymer molecules are oriented in the transverse direction, The stretching speed is 185m/min, the stretching temperature is 160°C, the setting temperature is 140°C, and the stretching ratio is 860%.

(6) Corona treatment

No need for corona treatment

(7) Winding

The performance of the ultra-low temperature heat-sealable wear-resistant BOPP film obtained in Examples 1 to 3 is analyzed, and the results are as follows:

1. Under the test conditions of temperature 75°C, pressure 0.18MPa, and contact time 1s, the heat seal strength of the outer/inner surface of the present invention reaches 2.5N/15mm;

2. According to GB/T31727-2015, the wear resistance index of the upper layer of the film is ≤0.1%;

In the range of 75°C to 90°C, the outer surface of the present invention can be well heat-sealed to the inner surface, and at the same time, in this temperature range, heat-sealing (blocking) does not occur with conventional BOPP films.

precise data:

Example 1: wear resistance index 0.1%, heat seal strength 3.2N/15mm (80°C, pressure 0.18MPa);

Example 2: wear resistance index 0.1%, heat seal strength 3.5N/15mm (80°C, pressure 0.18MPa);

Example 3: wear resistance index 0%, heat seal strength 3.0N/15mm (80°C, pressure 0.18MPa).

Claims

An ultra-low temperature heat-sealable wear-resistant BOPP film is characterized in that it includes an upper layer structure, a middle layer structure and a lower layer structure arranged in sequence;

The raw materials for forming the upper structure include: the first low-temperature heat-sealable metallocene, the first polydimethylsiloxane, silicone masterbatch, the first anti-blocking agent and the first copolymer; the first low-temperature heat-sealable The mass ratio of the permanent metallocene, the first polydimethylsiloxane, the silicone polymer material, the first anti-blocking agent and the first copolymer is (35-43): (5-10): (8- 15): (0.5～2): (35～43);

The raw materials forming the middle layer structure include: homopolypropylene, petroleum resin and antistatic agent; the mass ratio of homopolypropylene, petroleum resin and antistatic agent is (61.5～98.5):(0～35):(1.5 ~3.5);

The raw materials for forming the lower structure include: the second low-temperature heat-sealable metallocene, the second polydimethylsiloxane, the second anti-blocking agent and the second copolymer; the second low-temperature heat-sealable metallocene, the second The mass ratio of polydimethylsiloxane, the second anti-blocking agent and the second copolymer is (45-50): (0-10): (0.5-2): (40-50);

The first copolymer and the second copolymer are each independently selected from ethylene-propylene-butadiene terpolymers and/or ethylene-propylene binary copolymers.
The ultra-low temperature heat-seal wear-resistant BOPP film according to claim 1, characterized in that, the thickness of the ultra-low temperature heat-seal wear-resistant BOPP film is 18-50 μm;

The thickness of the superstructure is 0.5-1.0 μm;

The thickness of the middle layer structure is 16-48.8 μm;

The thickness of the lower layer structure is 0.7-1 μm.
The ultra-low temperature heat-sealable wear-resistant BOPP film according to claim 1, wherein the first low-temperature heat-sealable metallocene and the second low-temperature heat-sealable metallocene are each independently selected from Japan’s Sumitomo SP7731 and/or Basel Adsyl 7410XCP;

The molecular weights of the first polydimethylsiloxane and the second polydimethylsiloxane are independently 10,000 to 30,000;

The silicone masterbatch is a smooth masterbatch, and the carrier is polypropylene; the molecular weight of silicone in the silicone masterbatch is greater than 200,000; the effective content of silicone in the silicone masterbatch is 10% to 15% %;

The first anti-blocking agent and the second anti-blocking agent are independently selected from organic anti-blocking agents; the particle size of the organic anti-blocking agent is 2 to 4 μm;

The molecular weight of the homopolypropylene is 200,000 to 450,000; the melt index of the homopolypropylene is 2g/min to 4g/10min (230°C, 2.16Kg);

The petroleum resin is selected from C3 petroleum resin and/or C5 petroleum resin;

The antistatic agent is selected from polyamide antistatic agents;

The molecular weights of the first copolymer and the second copolymer are independently 30,000 to 70,000;

The molar ratio of ethylene monomer units, propylene monomer units and butadiene monomer units in the ethylene-propylene-butadiene terpolymer is 50:(20-40):(50-70);

The molar ratio of ethylene monomer units to propylene monomer units in the ethylene-propylene binary copolymer is (40-60):(40-60).
The ultra-low temperature heat-sealable wear-resistant BOPP film according to claim 1, wherein the silicone masterbatch is selected from one or more of silicone masterbatches whose brands are IL2580SC, SAB06554PPR and Taiwan Kenhua PSE99RP. various;

The first anti-blocking agent and the second anti-blocking agent are each independently selected from Schulman's brand ABVT22SC product and/or Japanese HIS04S;

The petroleum resin is selected from Jiangyin Jingliang's FS600A, the products of Beijing Duchen New Materials Co., Ltd. whose trademarks are PPMA66 and PPMA66H, the products of Hainan Mulong New Materials Co., Ltd. whose trademarks are ML8002 and Hainan Heli's HL8139. or more;

The antistatic agent is selected from one or more of the products of Beijing Duchen New Materials Co., Ltd. with the brand name of DS126T, Schulman's FASPA2955 and Suzhou Constamp Engineering Plastics Co., Ltd.'s product with the brand name of AT4023PP.
The ultra-low temperature heat-sealable wear-resistant BOPP film according to claim 1, wherein the molecular weight of the first polydimethylsiloxane and the second polydimethylsiloxane is 20,000;

The melt index of the homopolypropylene is 3g/10min (230°C, 2.16Kg);

The molecular weight of the first copolymer and the second copolymer is 45,000 to 55,000;

The molar ratio of ethylene monomer units, propylene monomer units and butadiene monomer units in the ethylene-propylene-butadiene terpolymer is 50:34:62;

The molar ratio of ethylene monomer units to propylene monomer units in the ethylene-propylene binary copolymer is (40-60):(40-60).
A preparation method of the ultra-low temperature heat-sealable wear-resistant BOPP film according to claim 1, characterized in that, comprising:

Ultra-low temperature heat-sealable wear-resistant BOPP film is obtained by co-extruding, casting, longitudinal stretching and transverse stretching of the raw materials of the upper layer structure, the middle layer structure and the lower layer structure.
The preparation method according to claim 6, characterized in that, during the co-extrusion process, the extrusion temperature of the raw materials of the upper structure is 180°C-225°C; the extrusion temperature of the raw materials of the middle structure is 235°C-260°C; The extrusion temperature of raw materials is 180°C to 220°C.
The preparation method according to claim 6, characterized in that the temperature of the cast sheet is 18°C-32°C.
The preparation method according to claim 6, characterized in that, preheating is carried out before the longitudinal stretching; the temperature of the preheating is 105° C. to 115° C.; the temperature of the longitudinal stretching is 60° C. to 70° C. °C; the setting temperature for longitudinal stretching is 72°C to 80°C; the ratio of longitudinal stretching is 450% to 620%.
The preparation method according to claim 6, characterized in that, preheating is carried out before the transverse stretching; the temperature of the preheating is 168°C-178°C; the temperature of the transverse stretching is 148°C-165°C °C; the setting temperature of transverse stretching is 105°C-165°C; the ratio of transverse stretching is 800%-1000%.