All-olefin composite film and preparation method and application thereof

Abstract

The application belongs to the technical field of packaging, and particularly relates to a full olefin composite film and a preparation method and application thereof. The composite film is composed of a BOPP film, an ink layer, an extrusion resin layer and a modified CPP film connected in sequence, the modified CPP film is composed of an extrusion layer, an intermediate layer and a heat sealing layer, the extrusion resin layer is composed of a first adhesive layer and a second adhesive layer, the first adhesive layer is connected with the ink layer, and the second adhesive layer is connected with the extrusion layer. The full olefin composite film does not use adhesive, is recyclable, has high transparency, high strength and is not easy to break.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging, in particular to an all-olefin composite film and a preparation method and application thereof. Background Art

[0002] Transparent tote bags are widely used in product promotional packaging. These outer bags are typically made from PET / PE or BOPP / CPP composite films. This packaging format is convenient for consumers purchasing small quantities and provides a complete package with handle holes for easy transport. Requirements for these outer bags include: excellent transparency to clearly display the packaged product; strong handle holes to ensure they will not break even after repeated handling; flexible composite film to prevent injury to the transporter's hands; and peel and seal strength to ensure they cannot be damaged by the weight of the contents.

[0003] Currently, this type of outer handbag has the following problems:

[0004] 1) The use of PET / PE composite film and adhesives will leave solvent residues, which not only poses food safety issues, but the purity of the final outer handbag is generally around 97%, which cannot be 100% recycled and reused, and is not environmentally friendly;

[0005] 2) Unable to clearly display the contents, with average transparency;

[0006] 2) The composite film of BOPP / CPP is too brittle, the handle strength is low and it is easy to break; the peeling and heat sealing strength are low, and it is easy to delaminate and break when pulling. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides an all-olefin composite film and its preparation method and application. The all-olefin composite film does not use adhesives, is recyclable, and has the advantages of high transparency, high strength, and is not easy to break.

[0008] In order to achieve one of the purposes of the present invention, the present invention adopts the following technical solutions:

[0009] An all-olefin composite film comprises a BOPP film, an ink layer, an extruded resin layer and a modified CPP film connected in sequence, wherein the modified CPP film comprises an extruded layer, an intermediate layer and a heat-sealing layer; the extruded layer comprises 80-90 parts by mass of random copolymerized polypropylene and 10-20 parts by mass of an ethylene-octene elastomer; the intermediate layer comprises 80-90 parts by mass of random copolymerized polypropylene and 10-20 parts by mass of a propylene-based elastomer; the heat-sealing layer comprises 60-70 parts by mass of metallocene copolymerized polypropylene, 25-35 parts by mass of metallocene polyethylene, 1.5-2.5 parts by mass of a slip agent and 2.5-3.5 parts by mass of a silicon oxide opening agent; and the extruded resin layer comprises a first adhesive layer and a second adhesive layer, wherein the first adhesive layer is connected to the ink layer and the second adhesive layer is connected to the extruded layer.

[0010] Preferably, the first adhesive layer is composed of 60-70 parts by mass of metallocene vinyl plastomer and 30-40 parts by mass of ethylene-methyl methacrylate copolymer; the second adhesive layer is composed of 100 parts by mass of metallocene vinyl plastomer; the ink used in the ink layer is GC single lipid environmentally friendly ink produced by Sony Ink Company.

[0011] Preferably, the brand of the metallocene vinyl plastomer is PT1450 produced by The Dow Chemical Company; the brand of the ethylene-methyl methacrylate copolymer is WH401-F produced by Sumitomo Corporation of Japan.

[0012] Preferably, the brand of random copolymer polypropylene is RD368CF produced by Borouge; the brand of ethylene-octene elastomer is ENGAGE8200 produced by DowDuPont; the brand of propylene-based elastomer is 3980 produced by Exxon; the brand of metallocene copolymer polypropylene is WFX4TA produced by Japan PP Company; the brand of metallocene polyethylene is SP0540 produced by Mitsui Company; the brand of slip agent is SLIP-7 produced by Aaron Company; and the brand of silica anti-blocking agent is AB-20LD produced by Aaron Company.

[0013] Preferably, the extruded layer is composed of 85 parts by mass of random copolymer polypropylene and 15 parts by mass of ethylene-octene elastomer, the intermediate layer is composed of 85 parts by mass of random copolymer polypropylene and 15 parts by mass of propylene-based elastomer, and the heat-sealing layer is composed of 65 parts by mass of metallocene copolymer polypropylene, 30 parts by mass of metallocene polyethylene, 2 parts by mass of a slip agent and 3 parts by mass of an opening agent.

[0014] Preferably, the thickness of the BOPP film is 18-38 μm; the thickness of the ink layer is 1-2 μm; the thickness of the extruded resin layer is 13-20 μm; and the thickness of the modified CPP film is 30-50 μm.

[0015] Preferably, the thickness ratio of the first adhesive layer to the second adhesive layer is 1:1.

[0016] Preferably, the BOPP film is made by printing a BOPP film.

[0017] In order to achieve the second object of the present invention, the present invention provides a method for preparing an all-olefin composite film, comprising the following steps:

[0018] S1. Preparation of modified CPP film: Weighing respective mass parts of extrusion layer resin, intermediate layer resin and heat seal layer resin, and sequentially performing co-extrusion casting, cooling and shaping, thickness measurement, slitting and winding to obtain modified CPP film;

[0019] S2. Preparation of extruded resin layer: Weigh the first adhesive layer resin and the second adhesive layer resin in parts by mass respectively, and sequentially pass them through a co-extrusion coating film of two extruders and one die head. When the coating film comes out of the die, immediately bond the first adhesive layer to the side of the BOPP film printed with the ink layer, and bond the second adhesive layer to the modified CPP film at the same time, and use auxiliary pressing rollers and quenching rollers to roll up after bonding and cooling to obtain an extruded composite film.

[0020] In order to achieve the third purpose of the present invention, the present invention provides an application of an all-olefin composite film, wherein the composite film is used to prepare a transparent handbag.

[0021] The beneficial effects of the present invention compared to the prior art are:

[0022] 1) The composite film of the present invention is an all-olefin film and does not use adhesives, which is more conducive to the recycling and granulation of composite film waste after consumption. The modified CPP film is designed with a high transparency and high flexibility formula and an optimized production process.

[0023] 2) The all-olefin composite film structure of the present invention improves the handle strength, increases the transparency of the bag, enhances the flexibility, and improves the peel strength and heat seal strength.

[0024] 3) The modified CPP film of the present invention uses copolymerized polypropylene and metallocene polypropylene resin, and adds an elastomer resin for toughening modification;

[0025] The extruded layer is a blend of random copolymer polypropylene and ethylene-octene elastomer. Ethylene-octene elastomer exhibits good compatibility with both polypropylene and polyethylene, enhancing adhesion strength (i.e., peel strength) to the extruded resin. The intermediate layer is a blend of random copolymer polypropylene and propylene-based elastomer. Propylene-based elastomer exhibits excellent compatibility with polypropylene and forms flexible segments, improving the flexibility of the modified CPP film. The heat-seal layer utilizes a blend of metallocene copolymer polypropylene and cast-grade metallocene polyethylene, with a lubricant and an anti-blistering agent added. The metallocene polyethylene resin exhibits low-temperature heat-sealability, high elongation, and excellent post-heat-seal flexibility, making the seal area less susceptible to cracking. The anti-blistering agent, an inorganic filler, creates a microscopic air layer between films, preventing vacuum adhesion. The lubricant, an erucamide-filled lubricant, is mobile and can migrate to the heat-seal surface of the film (i.e., the inner surface of the bag) after film formation, facilitating smooth bag opening and filling.

[0026] 4) The extruded resin in this invention is coextruded into an adhesive film using two adhesive layers. The metallocene vinyl plastomer used has good compatibility with polypropylene and polyethylene, providing strong adhesion to the unprinted areas of the BOPP film. The ethylene segments of the ethylene-methyl methacrylate copolymer used are highly compatible with the metallocene vinyl plastomer, while the methyl methacrylate segments exhibit excellent adhesion to the polyurethane ink layer. The adhesive layer attached to the modified CPP film is made of pure metallocene vinyl plastomer resin, which exhibits excellent adhesion to the extruded layer of the modified CPP film, resulting in a highly releasable composite film.

[0027] 5) Unlike conventional CPP films, the modified CPP film of the present invention does not require polarized corona treatment on the film surface during production, and its extrusion bonding is based on the compatibility mechanism of the resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural diagram of the present invention;

[0029] Figure 2 It is a schematic diagram of the process flow of the modified CPP film of the present invention.

[0030] The meanings of the symbols in the figure are as follows:

[0031] 1-BOPP film, 2-ink layer, 3-extruded resin layer, 4-modified CPP film. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0033] Example 1

[0034] An all-olefin composite film comprises a BOPP film 1, an ink layer 2, an extruded resin layer 3, and a modified CPP film 4, which are sequentially connected. The modified CPP film 4 comprises an extruded layer, an intermediate layer, and a heat-seal layer; the extruded resin layer 3 comprises a first adhesive layer and a second adhesive layer. The BOPP film 1 is 18 μm thick, the extruded resin layer 3 is 20 μm thick, and the modified CPP film 4 is 40 μm thick.

[0035] Among them, the first adhesive layer is connected to the ink layer 2, and the second adhesive layer is connected to the extruded layer; the extruded layer is composed of 80 parts by mass of random copolymer polypropylene and 20 parts by mass of ethylene-octene elastomer, the middle layer is composed of 90 parts by mass of random copolymer polypropylene and 10 parts by mass of propylene-based elastomer, and the heat-sealing layer is composed of 60 parts by mass of metallocene copolymer polypropylene, 35 parts by mass of metallocene polyethylene, 2.5 parts by mass of slip agent and 2.5 parts by mass of silica opening agent.

[0036] The first adhesive layer is composed of 60 parts by mass of metallocene vinyl plastomer and 40 parts by mass of ethylene-methyl methacrylate copolymer; the second adhesive layer is composed of 100 parts by mass of metallocene vinyl plastomer; the ink used in ink layer 2 is GC single lipid environmentally friendly ink produced by Sony Ink Company.

[0037] A method for preparing an all-olefin composite film comprises the following steps:

[0038] S1. Preparation of modified CPP film 4: Weigh the mass parts of extrusion layer resin, intermediate layer resin and heat seal layer resin respectively, and sequentially carry out co-extrusion casting, cooling and shaping, thickness measurement, slitting and winding to obtain modified CPP film 4. The process flow is as follows: Figure 2 As shown;

[0039] S2. Preparation of extruded resin layer 3: Weigh the first adhesive layer resin and the second adhesive layer resin in parts by mass respectively, and pass them through co-extrusion coating of two extruders and one die head in sequence. When the coating comes out of the die, immediately bond the first adhesive layer to the side of the BOPP film 1 printed with the ink layer 2, and bond the second adhesive layer to the modified CPP film 4, and use auxiliary pressing rollers and rapid cooling rollers to roll up after bonding and cooling to obtain the extruded composite film 1.

[0040] Example 2

[0041] An all-olefin composite film comprises a BOPP film 1, an ink layer 2, an extruded resin layer 3, and a modified CPP film 4, which are sequentially connected. The modified CPP film 4 comprises an extruded layer, an intermediate layer, and a heat-seal layer; the extruded resin layer 3 comprises a first adhesive layer and a second adhesive layer. The BOPP film 1 is 28 μm thick, the extruded resin layer 3 is 15 μm thick, and the modified CPP film 4 is 35 μm thick.

[0042] Among them, the first adhesive layer is connected to the ink layer 2, and the second adhesive layer is connected to the extruded layer; the extruded layer is composed of 85 parts by mass of random copolymer polypropylene and 15 parts by mass of ethylene-octene elastomer, the middle layer is composed of 85 parts by mass of random copolymer polypropylene and 15 parts by mass of propylene-based elastomer, and the heat-sealing layer is composed of 65 parts by mass of metallocene copolymer polypropylene, 30 parts by mass of metallocene polyethylene, 2 parts by mass of slip agent and 3 parts by mass of silica opening agent.

[0043] The first adhesive layer is composed of 70 parts by mass of metallocene vinyl plastomer and 30 parts by mass of ethylene-methyl methacrylate copolymer; the second adhesive layer is composed of 100 parts by mass of metallocene vinyl plastomer; the ink used in ink layer 2 is GC single lipid environmentally friendly ink produced by Sony Ink Company.

[0044] A method for preparing an all-olefin composite film comprises the following steps:

[0045] S1. Preparation of modified CPP film 4: Weigh the mass parts of extrusion layer resin, intermediate layer resin and heat seal layer resin respectively, and sequentially carry out co-extrusion casting, cooling and shaping, thickness measurement, slitting and winding to obtain modified CPP film 4. The process flow is as follows: Figure 2 As shown;

[0046] S2. Preparation of extruded resin layer 3: Weigh the first adhesive layer resin and the second adhesive layer resin in parts by mass respectively, and pass them through co-extrusion coating of two extruders and one die head in sequence. When the coating comes out of the die, immediately bond the first adhesive layer to the side of the BOPP film 1 printed with the ink layer 2, and bond the second adhesive layer to the modified CPP film 4 at the same time, and use auxiliary pressing rollers and rapid cooling rollers to roll up after bonding and cooling to obtain the extruded composite film 2.

[0047] Example 3

[0048] A full-olefin composite film, which consists of a BOPP film 1, an ink layer 2, an extruded resin layer 3 and a modified CPP film 4 connected in sequence. The modified CPP film 4 consists of an extruded layer, an intermediate layer and a heat-sealing layer; the extruded resin layer 3 consists of a first adhesive layer and a second adhesive layer.

[0049] The first adhesive layer is connected to the ink layer 2, and the second adhesive layer is connected to the extruded layer. The extruded layer is composed of 90 parts by weight of random copolymer polypropylene and 10 parts by weight of ethylene-octene elastomer. The intermediate layer is composed of 80 parts by weight of random copolymer polypropylene and 20 parts by weight of propylene-based elastomer. The heat-seal layer is composed of 70 parts by weight of metallocene copolymer polypropylene, 25 parts by weight of metallocene polyethylene, 1.5 parts by weight of a slip agent, and 3.5 parts by weight of a silicon oxide anti-blocking agent. The thickness of the BOPP film 1 is 38 μm, the thickness of the extruded resin layer 3 is 13 μm, and the thickness of the modified CPP film 4 is 30 μm.

[0050] The first adhesive layer is composed of 65 parts by mass of metallocene vinyl plastomer and 35 parts by mass of ethylene-methyl methacrylate copolymer; the second adhesive layer is composed of 100 parts by mass of metallocene vinyl plastomer; the ink used in ink layer 2 is GC single lipid environmentally friendly ink produced by Sony Ink Company.

[0051] A method for preparing an all-olefin composite film comprises the following steps:

[0052] S1. Preparation of modified CPP film 4: Weigh the mass parts of extrusion layer resin, intermediate layer resin and heat seal layer resin respectively, and sequentially carry out co-extrusion casting, cooling and shaping, thickness measurement, slitting and winding to obtain modified CPP film 4. The process flow is as follows: Figure 2 As shown;

[0053] S2. Preparation of extruded resin layer 3: Weigh the first adhesive layer resin and the second adhesive layer resin in parts by mass respectively, and pass them through co-extrusion coating of two extruders and one die head in sequence. When the coating comes out of the die, immediately bond the first adhesive layer to the side of the BOPP film 1 printed with the ink layer 2, and bond the second adhesive layer to the modified CPP film 4, and use auxiliary pressing rollers and rapid cooling rollers to roll up after bonding and cooling to obtain the extruded composite film 3.

[0054] The formula and particle performance parameters of the modified CPP films in Examples 1 to 3 are shown in Tables 1-2 below, and the casting process parameters of the modified CPP films are shown in Table 3 below:

[0055] Table 1 is the modified CPP film formula

[0056]

[0057] Table 2 Particle information table

[0058]

[0059] Table 3 Casting process parameters of modified CPP film

[0060]

[0061] Comparative Example 1

[0062] The composite film 4 is composed of a BOPP film with a thickness of 28 μm and a CPP film with a thickness of 50 μm.

[0063] Comparative Example 2

[0064] The composite film 5 is composed of a PET film with a thickness of 12 μm and a PE film with a thickness of 65 μm.

[0065] The composite film 2 prepared in Example 2 and the composite films 4-5 in Comparative Examples 1-2 were all prepared into handbags, and the performance of the handbags was tested. The results are shown in Table 4 below:

[0066] Table 4 Test results of composite film and bag making

[0067]

[0068] As can be seen from Table 4, the composite film prepared in Example 2 has the greatest tensile strength, and its peel strength and heat seal strength are significantly higher than those of Comparative Example 1. It also has the lowest haze, displays the contents most clearly, and has no breakage in the handle test. The material is made of all-olefin composites, and the post-consumer product can be recycled at a high value and can be reused, meeting environmental protection requirements.

Claims

1. An all-olefin composite film, characterized in that: The composite film is composed of a BOPP film (1), an ink layer (2), an extruded resin layer (3) and a modified CPP film (4) connected in sequence, wherein the modified CPP film (4) is composed of an extruded layer, an intermediate layer and a heat-sealing layer; the extruded layer is composed of 80-90 parts by mass of random copolymerized polypropylene and 10-20 parts by mass of ethylene-octene elastomer, the intermediate layer is composed of 80-90 parts by mass of random copolymerized polypropylene and 10-20 parts by mass of propylene-based elastomer, and the heat-sealing layer is composed of 60-70 parts by mass of metallocene copolymerized polypropylene, 25-35 parts by mass of metallocene polyethylene, 1.5-2.5 parts by mass of a slip agent and 2.5-3.5 parts by mass of a silicon oxide opening agent; the extruded resin layer (3) is composed of a first adhesive layer and a second adhesive layer, the first adhesive layer is connected to the ink layer (2), and the second adhesive layer is connected to the extruded layer; The first adhesive layer is composed of 60-70 parts by mass of metallocene vinyl plastomer and 30-40 parts by mass of ethylene-methyl methacrylate copolymer; the second adhesive layer is composed of 100 parts by mass of metallocene vinyl plastomer; the ink used in the ink layer (2) is GC single lipid environmentally friendly ink produced by Sony Ink Company.

2. The all-olefin composite film according to claim 1, characterized in that: The brand of the metallocene vinyl plastomer is PT1450 produced by Dow Chemical Company; the brand of the ethylene-methyl methacrylate copolymer is WH401-F produced by Sumitomo Corporation of Japan.

3. The all-olefin composite film according to claim 1, characterized in that: The brand of the random copolymer polypropylene is RD368CF produced by Borouge; the brand of the ethylene-octene elastomer is ENGAGE8200 produced by DowDuPont; the brand of the propylene-based elastomer is 3980 produced by Exxon; the brand of the metallocene copolymer polypropylene is WFX4TA produced by Japan PP; the brand of the metallocene polyethylene is SP0540 produced by Mitsui; the brand of the slip agent is SLIP-7 produced by Aaron; and the brand of the silica anti-blocking agent is AB-20LD produced by Aaron.

4. The all-olefin composite film according to claim 1, characterized in that: The extruded layer is composed of 85 parts by mass of random copolymerized polypropylene and 15 parts by mass of ethylene-octene elastomer, the intermediate layer is composed of 85 parts by mass of random copolymerized polypropylene and 15 parts by mass of propylene-based elastomer, and the heat-sealing layer is composed of 65 parts by mass of metallocene copolymerized polypropylene, 30 parts by mass of metallocene polyethylene, 2 parts by mass of a slip agent and 3 parts by mass of an anti-blocking agent.

5. The all-olefin composite film according to claim 1, characterized in that: The thickness of the BOPP film (1) is 18-38 μm; the thickness of the ink layer (2) is 1-2 μm; the thickness of the extruded resin layer (3) is 13-20 μm; and the thickness of the modified CPP film (4) is 30-50 μm.

6. The all-olefin composite film according to claim 1, characterized in that: The thickness ratio of the first adhesive layer to the second adhesive layer is 1:

1.

7. The all-olefin composite film according to claim 1, characterized in that: The BOPP film (1) is made by printing a BOPP film.

8. A method for preparing an all-olefin composite film according to any one of claims 1 to 7, characterized in that: The steps include: S1. Preparation of modified CPP film (4): Weighing respective weight portions of extrusion layer resin, intermediate layer resin and heat seal layer resin, and sequentially subjecting the film to co-extrusion casting, cooling and shaping, thickness measurement, slitting and winding to obtain modified CPP film (4); S2. Preparation of extruded resin layer (3): Weigh the first adhesive layer resin and the second adhesive layer resin in respective mass parts, and sequentially pass them through a co-extrusion coating machine with a die head of two extruders. When the coating film exits the die, immediately bond the first adhesive layer to the side of the BOPP film (1) printed with the ink layer (2), and bond the second adhesive layer to the modified CPP film (4). Assisted by lamination rollers and quenching rollers, the films are rolled up after bonding and cooling to obtain an extruded composite film.

9. An application of the all-olefin composite film according to any one of claims 1 to 7, characterized in that: The composite film is used to prepare a transparent handbag.

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