A directly printable film and its production process and application

Abstract

This invention relates to the field of thin film processing technology, and discloses a directly printable film, its production process, and its applications. The film has a 4-9 layer co-extruded structure; it comprises an upper surface layer, a second upper surface layer, a core layer, and a lower surface layer stacked sequentially from top to bottom; the upper surface layer is the directly printable surface; the second upper surface layer can bond the upper surface layer and the core layer; the core layer is the skeleton part of the film; and the lower surface layer is a masking functional layer. The directly printable film produced by this invention exhibits excellent absorption of water-based inks, and after printing, the ink does not bleed, does not shrink, and the film maintains a good appearance. This film can be directly applied to water-based ink printing without the need to coat the film substrate with an ink-absorbing coating, reducing processing costs and allowing for reasonable control of the printing effect.

Description

Technical Field

[0001] This invention relates to the field of thin film processing technology, specifically to a directly printable thin film, its production process, and its applications. Background Technology

[0002] Currently, most synthetic paper products on the market that use BOPP film as the substrate require an ink-absorbing layer as an ink adhesion material before water-based ink printing can be performed. Some substrates even require a primer (as an adhesive layer), which is dried before an ink-absorbing layer is applied on top of the primer for printing. Synthetic paper substrates without an ink-absorbing layer cannot be directly used for water-based ink printing.

[0003] Currently, all synthetic paper products require further processing, which not only increases processing costs, but also poses a significant risk to the control of printing effects due to the inconsistent coating formulas used by different coating manufacturers.

[0004] Therefore, it is necessary to develop a directly printable film, its production process, and its applications. The produced film can be directly applied to water-based ink printing without the need to coat the film substrate with an ink-absorbing coating, thus reducing processing costs and allowing for reasonable control of the printing effect. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a directly printable film, its production process, and its application. The produced film can be directly applied to water-based ink printing without the need to coat the film substrate with an ink-absorbing coating, thus reducing processing costs and allowing for reasonable control of the printing effect.

[0006] The inventive concept of this invention:

[0007] A first aspect of the present invention provides a directly printable film.

[0008] Specifically, the film has a 4-9 layer co-extruded structure; the film comprises an upper surface layer, a second upper surface layer, a core layer, and a lower surface layer stacked sequentially from top to bottom; the upper surface layer is a directly printable surface; the second upper surface layer bonds the upper surface layer and the core layer; the core layer is the skeleton part of the film; and the lower surface layer is a masking functional layer.

[0009] Preferably, the function of the upper surface layer is to absorb water and fix pigments, and it is a surface layer that can be directly printed with water-based inks; the secondary upper surface layer can enhance the interlayer bonding ability of the film; the core layer is the main extrusion layer, which can provide different thicknesses, and the film material is white after foaming, and can partially replace paper; the lower surface layer is a cover layer, and can also be used as a film additive for the core layer, and provide good surface processing conditions.

[0010] Preferably, the film further includes a functional layer and an adhesive layer stacked sequentially from top to bottom between the second upper surface layer and the core layer; the film further includes an adhesive layer, a functional layer, and an adhesive layer stacked sequentially from top to bottom between the core layer and the lower surface layer.

[0011] More preferably, the functional layer is added with different thin film additives to achieve its functional purpose, including but not limited to flame retardancy, aging resistance, and biodegradability.

[0012] Preferably, the raw materials of the upper surface layer include, by weight: 50-70 parts corn starch, 10-20 parts hydroxypropyl methylcellulose, 10-20 parts polyurethane, 3-5 parts organotin stabilizer, 5-10 parts calcium-zinc stabilizer, 1-3 parts anti-aging agent, and 0.5-2 parts silicon dioxide.

[0013] More preferably, the organotin stabilizer includes, but is not limited to, isooctyltin dimercaptoacetate (DOTTG), isooctyltin dimethyldimercaptoacetate (DMTFG), dibutyltin dilaurate (DBTL), and dioctyltin dilaurate (DOTL).

[0014] More preferably, the calcium-zinc stabilizer is a mixture of calcium stearate, zinc stearate, dihydroxypropyl octadecanoate, and an antioxidant.

[0015] More preferably, the antioxidant is antioxidant 1076.

[0016] Preferably, the raw materials of the secondary upper surface layer include, by weight, 80-90 parts polypropylene, 10-20 parts polyalkyl acrylic acid, and 1-3 parts maleic anhydride.

[0017] Preferably, the raw materials of the core layer include, by weight, 60-80 parts polypropylene, 10-20 parts calcium carbonate, 5-10 parts titanium dioxide, and 1-3 parts dihydroxypropyl octadecanoate.

[0018] Preferably, the raw materials of the lower surface layer include, by weight, 95-98 parts of polyolefin and 2-5 parts of silicon dioxide.

[0019] Preferably, the thickness of the upper surface layer is 5-20 μm; the thickness of the second upper surface layer is 5-8 μm; the thickness of the core layer is 30-100 μm; and the thickness of the lower surface layer is 5-10 μm.

[0020] Preferably, the thickness of the functional layer is 1 to 100 μm.

[0021] A second aspect of the present invention provides a manufacturing process for a directly printable thin film.

[0022] Specifically, it includes the following steps:

[0023] (1) Control the extrusion temperature of each co-extruded layer of the film; the extrusion temperature of the upper surface layer is 220-250℃, the extrusion temperature of the second upper surface layer is 220-250℃, the extrusion temperature of the core layer is 220-260℃, and the extrusion temperature of the lower surface layer is 190-220℃.

[0024] (2) After casting, double stretching is performed, and the longitudinal stretching ratio is adjusted to 2 to 4 times, and the transverse stretching ratio is 4 to 6 times.

[0025] (3) After stretching, the lower surface layer is subjected to corona treatment;

[0026] (4) After winding, age for 24-72 hours and then cut into finished products to obtain film.

[0027] Preferably, in step (2), the longitudinal stretching ratio is 2.5 times and the transverse stretching ratio is 4 times.

[0028] Preferably, in step (3), the corona treatment value is 45 to 55 dynes.

[0029] More preferably, the corona treatment value is 50 dynes.

[0030] Preferably, in step (4), the film is obtained by aging after winding for 48 hours and then cutting the finished product.

[0031] Preferably, the extrusion temperature of the functional layer is 190-260℃.

[0032] A third aspect of the present invention provides an application of a directly printable film in the fields of label printing substrates, self-adhesive label substrates, electronic product label substrates, food label substrates, beverage label substrates, inkjet printing supplies, label materials, outdoor advertising, and posters.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] The printable film produced by this invention exhibits excellent absorption of water-based inks, preventing ink bleeding and shrinkage after printing, and maintaining a pristine film appearance. This film can be directly applied to water-based ink printing without the need for an ink-absorbing coating on the film substrate, reducing processing costs and allowing for reasonable control over printing results. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of a directly printable film containing four co-extruded layers.

[0036] Figure 2 This is a schematic diagram of a directly printable film containing nine co-extruded layers. Detailed Implementation

[0037] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0038] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0039] Example 1

[0040] A directly printable film and its manufacturing process.

[0041] Printable films:

[0042] The co-extruded layer has 4 layers, such as Figure 1 As shown, the thin film is composed of an upper surface layer, a second upper surface layer, a core layer, and a lower surface layer stacked sequentially from top to bottom.

[0043] Top layer: 50 parts corn starch, 20 parts hydroxypropyl methylcellulose, 20 parts polyurethane, 1.5 parts dimethyldimercaptoacetate isooctyltin (DOTTG), 1.5 parts dimethyldimercaptoacetate isooctyltin (DMTFG), 5 parts calcium-zinc stabilizer (this stabilizer is a mixture of calcium stearate, zinc stearate, dihydroxypropyl octadecanoate, and antioxidant), 1 part anti-aging agent 1010; 1 part silica.

[0044] Secondary top layer: 85 parts polypropylene, 13 parts polyalkyl acrylic acid, 2 parts maleic anhydride.

[0045] Core layer: 70 parts polypropylene, 20 parts calcium carbonate, 8 parts titanium dioxide, and 2 parts dihydroxypropyl octadecanoate.

[0046] Bottom layer: 80 parts polypropylene, 18 parts ethylene-propylene copolymer, 2 parts silica.

[0047] The thickness of the top layer is 10 μm, the thickness of the second top layer is 8 μm, the thickness of the core layer is 50 μm, and the thickness of the bottom layer is 10 μm.

[0048] Specific production process:

[0049] (1) The extrusion temperature of the upper surface layer is 245℃, the extrusion temperature of the second upper surface layer is 220℃, the extrusion temperature of the core layer is 235℃, and the extrusion temperature of the lower surface layer is 210℃.

[0050] (2) After casting, the longitudinal stretching ratio is 2.5 times and the transverse stretching ratio is 4 times.

[0051] (3) After stretching, the lower surface layer is subjected to corona treatment with a corona treatment value of 50 dynes.

[0052] (4) After winding, the product is aged for 48 hours and then cut into finished products.

[0053] Example 1: Finished film product results: The film exhibits good absorption of water-based inks; the ink does not bleed or shrink after printing. The film maintains a perfect appearance.

[0054] Example 2

[0055] A directly printable film and its manufacturing process.

[0056] Printable films:

[0057] The co-extruded layer consists of four layers, and the film is composed of an upper surface layer, a second upper surface layer, a core layer, and a lower surface layer stacked from top to bottom.

[0058] Top layer: 60 parts corn starch, 20 parts hydroxypropyl methylcellulose, 10 parts polyurethane, 1.5 parts dimethyldimercaptoacetate isooctyltin (DOTTG), 1.5 parts dimethyldimercaptoacetate isooctyltin (DMTFG), 5 parts calcium-zinc stabilizer (this stabilizer is a mixture of calcium stearate, zinc stearate, dihydroxypropyl octadecanoate, and antioxidant), 1 part anti-aging agent 1010; 1 part silica.

[0059] Secondary top layer: 85 parts polypropylene, 13 parts polyalkyl acrylic acid, 2 parts maleic anhydride.

[0060] Core layer: 70 parts polypropylene, 20 parts calcium carbonate, 8 parts titanium dioxide, and 2 parts dihydroxypropyl octadecanoate.

[0061] Bottom layer: 80 parts polypropylene, 18 parts ethylene-propylene copolymer, 2 parts silica.

[0062] The thickness of the top layer is 10 μm, the thickness of the second top layer is 8 μm, the thickness of the core layer is 50 μm, and the thickness of the bottom layer is 10 μm.

[0063] Specific production process:

[0064] (1) The extrusion temperature of the upper surface layer is 250℃, the extrusion temperature of the second upper surface layer is 220℃, the extrusion temperature of the core layer is 235℃, and the extrusion temperature of the lower surface layer is 210℃.

[0065] (2) After casting, the longitudinal stretching ratio is 2.5 times and the transverse stretching ratio is 4 times.

[0066] (3) After stretching, the lower surface layer is subjected to corona treatment with a corona treatment value of 50 dynes.

[0067] (4) After winding, the product is aged for 48 hours and then cut into finished products.

[0068] Example 2: Finished film product results: The film exhibits good absorption of water-based inks; the ink does not bleed or shrink after printing. Slight cracks are present on the surface of the film.

[0069] Comparative Example 1

[0070] A directly printable film and its manufacturing process.

[0071] Printable films:

[0072] The co-extruded layer consists of four layers, and the film is composed of an upper surface layer, a second upper surface layer, a core layer, and a lower surface layer stacked from top to bottom.

[0073] Top layer: 80 parts corn starch, 5 parts hydroxypropyl methylcellulose, 5 parts polyurethane, 1.5 parts dimethyldimercaptoacetate isooctyltin (DOTTG), 1.5 parts dimethyldimercaptoacetate isooctyltin (DMTFG), 5 parts calcium-zinc stabilizer (the stabilizer is a mixture of calcium stearate, zinc stearate, dihydroxypropyl octadecanoate, and antioxidant), 1 part anti-aging agent 1010; 1 part silica.

[0074] Secondary top layer: 85 parts polypropylene, 13 parts polyalkyl acrylic acid, 2 parts maleic anhydride.

[0075] Core layer: 70 parts polypropylene, 20 parts calcium carbonate, 8 parts titanium dioxide, and 2 parts dihydroxypropyl octadecanoate.

[0076] Bottom layer: 80 parts polypropylene, 18 parts ethylene-propylene copolymer, 2 parts silica.

[0077] The thickness of the top layer is 10 μm, the thickness of the second top layer is 8 μm, the thickness of the core layer is 50 μm, and the thickness of the bottom layer is 10 μm.

[0078] Specific production process:

[0079] (1) The extrusion temperature of the upper surface layer is 250℃, the extrusion temperature of the second upper surface layer is 220℃, the extrusion temperature of the core layer is 235℃, and the extrusion temperature of the lower surface layer is 210℃.

[0080] (2) After casting, the longitudinal stretching ratio is 2.5 times and the transverse stretching ratio is 4 times.

[0081] (3) After stretching, the lower surface layer is subjected to corona treatment with a corona treatment value of 50 dynes.

[0082] (4) After winding, the product is aged for 48 hours and then cut into finished products.

[0083] Comparative Example 1: Finished film product: There are obvious cracks on the surface of the film. The film has good absorption of water-based ink, but the printed pattern is deformed and there is bleeding after ink is printed.

[0084] Comparative Example 2

[0085] A directly printable film and its manufacturing process.

[0086] Printable films:

[0087] The co-extruded layer consists of four layers, and the film is composed of an upper surface layer, a second upper surface layer, a core layer, and a lower surface layer stacked from top to bottom.

[0088] Top layer: 30 parts corn starch, 30 parts hydroxypropyl methylcellulose, 30 parts polyurethane, 1.5 parts dimethyldimercaptoacetate isooctyltin (DOTTG), 1.5 parts dimethyldimercaptoacetate isooctyltin (DMTFG), 5 parts calcium-zinc stabilizer (this stabilizer is a mixture of calcium stearate, zinc stearate, dihydroxypropyl octadecanoate, and antioxidant), 1 part anti-aging agent 1010; 1 part silica.

[0089] Secondary top layer: 85 parts polypropylene, 13 parts polyalkyl acrylic acid, 2 parts maleic anhydride.

[0090] Core layer: 70 parts polypropylene, 20 parts calcium carbonate, 8 parts titanium dioxide, and 2 parts dihydroxypropyl octadecanoate.

[0091] Bottom layer: 80 parts polypropylene, 18 parts ethylene-propylene copolymer, 2 parts silica.

[0092] The thickness of the top layer is 10 μm, the thickness of the second top layer is 8 μm, the thickness of the core layer is 50 μm, and the thickness of the bottom layer is 10 μm.

[0093] Specific production process:

[0094] (1) The extrusion temperature of the upper surface layer is 245℃, the extrusion temperature of the second upper surface layer is 220℃, the extrusion temperature of the core layer is 235℃, and the extrusion temperature of the lower surface layer is 210℃.

[0095] (2) After casting, the longitudinal stretching ratio is 2.5 times and the transverse stretching ratio is 4 times.

[0096] (3) After stretching, the lower surface layer is subjected to corona treatment with a corona treatment value of 50 dynes.

[0097] (4) After winding, the product is aged for 48 hours and then cut into finished products.

[0098] Comparative Example 2: Finished film product: The film has a good appearance, but the film has poor adsorption of water-based inks and exhibits ink detachment.

[0099] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, any technical solutions obtained by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concept of the present invention and on the existing technology should be within the scope of protection defined by the claims.

Claims

1. A directly printable film, characterized in that, The film has a 4-9 layer co-extruded structure; the film comprises an upper surface layer, a second upper surface layer, a core layer, and a lower surface layer stacked from top to bottom; the upper surface layer is a directly printable surface. The secondary upper surface layer is bonded to the upper surface layer and the core layer; The core layer is the skeleton part of the thin film; The lower surface layer is a covering functional layer, and the raw materials of the upper surface layer include, by weight: 50-70 parts corn starch, 10-20 parts hydroxypropyl methylcellulose, 10-20 parts polyurethane, 3-5 parts organotin stabilizer, 5-10 parts calcium-zinc stabilizer, 1-3 parts anti-aging agent, and 0.5-2 parts silicon dioxide.

2. The thin film according to claim 1, characterized in that, The film further includes a functional layer and an adhesive layer stacked sequentially from top to bottom between the second upper surface layer and the core layer; the film further includes an adhesive layer, a functional layer, and an adhesive layer stacked sequentially from top to bottom between the core layer and the lower surface layer.

3. The thin film according to claim 1, characterized in that, The raw materials of the sub-top layer include, by weight, 80-90 parts polypropylene, 10-20 parts polyalkyl acrylic acid, and 1-3 parts maleic anhydride.

4. The thin film according to claim 1, characterized in that, The raw materials of the core layer include, by weight, 60-80 parts polypropylene, 10-20 parts calcium carbonate, 5-10 parts titanium dioxide, and 1-3 parts dihydroxypropyl octadecanoate.

5. The thin film according to claim 1, characterized in that, The raw materials of the lower surface layer include, by weight, 95-98 parts of polyolefin and 2-5 parts of silicon dioxide.

6. The thin film according to claim 1, characterized in that, The thickness of the upper surface layer is 5-20 μm; the thickness of the second upper surface layer is 5-8 μm; the thickness of the core layer is 30-100 μm; and the thickness of the lower surface layer is 5-10 μm.

7. The film production process according to any one of claims 1 to 6, characterized in that, Includes the following steps: (1) Control the extrusion temperature of each co-extruded layer of the film; the extrusion temperature of the upper surface layer is 220~250℃, the extrusion temperature of the second upper surface layer is 220~250℃, the extrusion temperature of the core layer is 220~260℃, and the extrusion temperature of the lower surface layer is 190~220℃. (2) After casting, double stretching is performed, and the longitudinal stretching ratio is adjusted to 2 to 4 times, and the transverse stretching ratio is 4 to 6 times; (3) After stretching, the lower surface layer is subjected to corona treatment; (4) After winding, age for 24~72h and cut into finished products to obtain film.

8. The production process according to claim 7, characterized in that, In step (3), the corona treatment value is 45~55 dynes.

9. The application of the film according to any one of claims 1 to 6 in the fields of label printing substrates, self-adhesive label substrates, electronic product label substrates, food label substrates, beverage label substrates, inkjet printing products, outdoor advertising, and posters.

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