A printing ink for a treatment-free plastic film, and a preparation method and application thereof

Abstract

The application discloses a printing ink for a non-treatment plastic film and a preparation method and application thereof, and belongs to the technical field of polymer materials. The printing ink for the non-treatment plastic film comprises the following raw materials in mass fractions: 40-70 parts of polyamide resin, 5-35 parts of polyketone resin, 1-20 parts of wax, 3-70 parts of an organic solvent, 0.1-2 parts of a dispersing agent and 3-20 parts of a pigment. The polyamide resin and the polyketone resin are combined, so that the adhesion of the printing ink on the film can be effectively improved; the printing film does not need to be subjected to a pre-treatment such as a corona treatment, and good adhesion can be provided; the printing effect is good; the printing ink has good wear resistance; the printed product can withstand the wear in daily use, has good durability and aesthetic degree, and can be widely applied in various fields such as food packaging, cosmetic packaging, medicine packaging and decorative products.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, and particularly relates to a printing ink for treatment-free plastic films, its preparation method, and its application. Background Technology

[0002] In the packaging industry, pre-treatment-free plastic films can be used for food packaging, pharmaceutical packaging, and agricultural films. Due to their excellent moisture resistance, corrosion resistance, impact resistance, and transparency, they effectively protect products and extend their shelf life. In the printing industry, pre-treatment-free plastic films can be printed directly without surface treatments such as corona treatment, simplifying the printing process and improving production efficiency. In the decoration industry, pre-treatment-free plastic films can be used to make various decorative items, such as wall stickers and billboards. Due to their excellent mechanical properties, thermal stability, and chemical stability, they can maintain their decorative effect for a long time.

[0003] Because the surface of pre-treated plastic films is often quite smooth, printing inks must have excellent adhesion to ensure the quality and effect of the printed materials. Furthermore, since pre-treated plastic films frequently come into contact with surfaces, printing inks must have good abrasion resistance to ensure the printed materials can withstand the wear and tear of daily use. However, ordinary printing inks on the market have high requirements for the substrate treatment level during use. For example, PE film requires a treatment level greater than 38 dynes, OPP film requires a treatment level greater than 38-42 dynes, and nylon film requires a treatment level greater than 52 dynes, etc. Moreover, ordinary printing inks have poor abrasion resistance, easily causing scratches and peeling of the ink layer when in contact with other surfaces, affecting the appearance and quality of the printed materials. Therefore, ordinary printing inks do not meet the performance requirements of pre-treated plastic films and cannot be used normally on them. Summary of the Invention

[0004] In order to overcome the problems existing in the prior art, one of the objectives of the present invention is to provide a printing ink for untreated plastic films, which has good adhesion and can achieve good printing results.

[0005] A second objective of this invention is to provide a method for preparing the above-mentioned printing ink.

[0006] The third objective of this invention is to provide an application of the above-mentioned printing ink.

[0007] The fourth objective of this invention is to provide a printed article.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A first aspect of the present invention provides a printing ink for a treatment-free plastic film, comprising the following raw materials in parts by weight: 40-70 parts polyamide resin, 5-35 parts polyketone resin, 1-20 parts wax, 3-70 parts organic solvent, 0.1-2 parts dispersant, and 3-20 parts pigment.

[0010] Preferably, in the printing ink, the polyamide resin has a viscosity of 20–60 mPa·s at 25°C; more preferably, it has a viscosity of 30–50 mPa·s.

[0011] Preferably, the polyamide resin in the printing ink has a softening point of 80–110°C; more preferably, it has a softening point of 90–100°C.

[0012] Preferably, the polyamide resin in the printing ink has an amine value ≤4; more preferably, it has a value of 1 to 3.

[0013] Using a polyamide resin that meets at least one of the properties of viscosity, softening point, and amine value as required by this invention enables better interaction between the polyamide resin and other raw materials of this invention. Introducing this specific polyamide resin into this invention can result in printing ink with further improved adhesion performance. Good adhesion can be achieved without pretreating the plastic film being printed.

[0014] In a specific embodiment of the present invention, the polyamide resin is selected from HY-356 polyamide resin. HY-356 polyamide resin has a viscosity of 30-50 mPa·s at 25°C, a softening point of 95±5°C, an amine value ≤3, and a color of 12 as measured by an iron-cobalt colorimeter. Adding HY-356 polyamide resin significantly improves the wettability of pigments in the printing ink of the present invention and significantly improves film adhesion, eliminating the need for corona treatment of the substrate plastic film to obtain printed products with good adhesion.

[0015] Preferably, in the printing ink, the polyamide resin is used as one of the raw materials for preparing the printing ink in the form of a solution. In the printing ink of the present invention, the amount of polyamide resin refers to the amount of polyamide resin solution used.

[0016] Preferably, the organic solvent of the polyamide resin solution includes at least one of methylcyclohexane, ethyl acetate, or isopropanol; more preferably, the organic solvent of the polyamide resin solution includes methylcyclohexane, ethyl acetate, and isopropanol; even more preferably, the organic solvent of the polyamide resin solution includes the following components in parts by weight: 15-20 parts methylcyclohexane, 10-15 parts ethyl acetate, and 25-35 parts isopropanol.

[0017] Preferably, the solid content of the polyamide resin solution in the printing ink is 30-50 wt%; more preferably 35-45 wt%.

[0018] Preferably, the polyamide resin in the printing ink comprises 45 to 65 parts by weight; more preferably, it comprises 45 to 60 parts by weight.

[0019] Preferably, in the printing ink, the polyamide resin accounts for 40-70 wt% of the raw materials used in the printing ink preparation; more preferably, 45-65 wt%; and even more preferably, 55-60 wt%.

[0020] By optimizing the proportion of polyamide resin added to the printing ink, the adhesion of the printing ink to untreated plastic films can be further improved.

[0021] Preferably, in the printing ink, the polyketone resin is a polymer of saturated aldehydes and saturated ketones.

[0022] Preferably, in the printing ink, the hydroxyl value of the polyketone resin is 70-110 mgKOH / g; more preferably, it is 80-100 mgKOH / g.

[0023] Preferably, the softening point of the polyketone resin in the printing ink is 105-130°C; more preferably, it is 111-125°C.

[0024] In a specific embodiment of the present invention, the polyketone resin is selected from CF-120 polyketone resin. CF-120 polyketone resin is a polymer of saturated ketones and saturated aldehydes, with a hydroxyl value of 80-100 mgKOH / g and a softening point of 111-125℃. Adding CF-120 polyketone resin can improve the gloss, fullness, toughness, hardness, impact resistance, adhesion, corrosion resistance, yellowing resistance, and weather resistance of the ink coating of the present invention, and can also improve the wetting and leveling properties of pigments in the ink.

[0025] Preferably, in the printing ink, the polyketone resin is used as one of the raw materials for preparing the printing ink in the form of a solution. In the printing ink of the present invention, the amount of polyketone resin used refers to the amount of polyketone resin solution used.

[0026] Preferably, the organic solvent of the polyketone resin solution includes at least one selected from methylcyclohexane, ethyl acetate, ethanol, or isopropanol; more preferably, the organic solvent of the polyketone resin solution includes methylcyclohexane, ethyl acetate, ethanol, and isopropanol; even more preferably, the organic solvent of the polyketone resin solution includes the following components in parts by weight: 30-40 parts methylcyclohexane, 7-15 parts ethyl acetate, 7-15 parts ethanol, and 7-15 parts isopropanol.

[0027] Preferably, the solid content of the polyketone resin solution in the printing ink is 25-45 wt%; more preferably 30-40 wt%.

[0028] Preferably, the polyketone resin in the printing ink comprises 10 to 30 parts by weight; more preferably 15 to 25 parts by weight.

[0029] Preferably, in the printing ink, the wax comprises erucamide wax, polyethylene wax, or a combination thereof; more preferably, the wax comprises erucamide wax and polyethylene wax; even more preferably, the wax comprises erucamide wax and polyethylene wax in a mass ratio of 1:(0.8-1.2).

[0030] In a specific embodiment of the present invention, the erucic acid amide wax powder is selected from Croda erucic acid amide ER wax powder from the UK. Croda erucic acid amide ER wax powder is an erucic acid amide wax powder produced by Croda Company of the UK using plants. It is available in two forms: powder and microbeads. The softening point is 79-86 degrees Celsius. The particle size of the microbeads is 0.1-0.5 mm, and the particle size of the powder is 0.01-0.1 mm. Adding Croda erucic acid amide ER wax powder can effectively reduce the friction of the ink of the present invention and improve the ink's anti-sticking, anti-wear, anti-scratch, and slip properties.

[0031] In a specific embodiment of the present invention, the polyethylene wax powder is selected from Clariant 3620 polyethylene wax powder. Clariant 3620 polyethylene wax powder is a microcrystalline, colorless, odorless, high-density polyethylene wax with an average particle size of approximately 8.5 micrometers. Adding Clariant 3620 polyethylene wax powder can give the liquid ink of the present invention good anti-abrasion and anti-caking properties.

[0032] Preferably, in the printing ink, the wax is used as one of the raw materials for preparing the printing ink in the form of a solution. In the printing ink of the present invention, the amount of wax refers to the amount of wax solution (or wax paste).

[0033] Preferably, the organic solvent of the wax solution includes at least one of n-propyl acetate, ethyl acetate, or isopropanol; more preferably, the organic solvent of the wax solution includes n-propyl acetate, ethyl acetate, and isopropanol; even more preferably, the organic solvent of the wax solution includes the following components in parts by weight: 8-12 parts of n-propyl acetate, 50-60 parts of ethyl acetate, and 2-5 parts of isopropanol.

[0034] Preferably, the solid content of the wax solution in the printing ink is 20-40 wt%; more preferably 25-35 wt%.

[0035] Preferably, the wax in the printing ink comprises 3 to 15 parts by weight; more preferably 5 to 10 parts by weight.

[0036] Preferably, in the printing ink, the organic solvent includes at least one of methylcyclohexane, ethyl acetate, or isopropanol; more preferably, in the printing ink, the organic solvent includes methylcyclohexane, ethyl acetate, and isopropanol; even more preferably, in the printing ink, the organic solvent includes the following components in parts by weight: 1-20 parts methylcyclohexane, 1-15 parts ethyl acetate, and 3-25 parts isopropanol.

[0037] This invention uses methylcyclohexane, ethyl acetate and isopropanol as organic solvents, which can adjust the viscosity and drying speed of the ink.

[0038] Preferably, the organic solvent in the printing ink comprises 4 to 65 parts by mass; more preferably 5 to 60 parts by mass.

[0039] Preferably, in the printing ink, the dispersant is selected from polymeric dispersants.

[0040] In a specific embodiment of the present invention, the dispersant is selected from Lubrizol Solplus L300 dispersant. Lubrizol Solplus L300 dispersant is a 100% active polymer dispersant that can improve the dispersibility and stability of pigments in the inks of the present invention.

[0041] Preferably, the dispersant in the printing ink is 0.2 to 1.5 parts by mass; more preferably 0.3 to 1 part by mass.

[0042] Preferably, in the printing ink, the pigment includes at least one of white pigment, yellow pigment, red pigment, blue pigment, black pigment, or green pigment.

[0043] In specific embodiments of the present invention, the pigments may be selected from the following types: white pigment can be purchased from Shandong Dongjia Group Co., Ltd., model: Titanium Dioxide SR-2377; yellow pigment can be purchased from Hangzhou Baihe Chemical Co., Ltd., model: Permanent Yellow BHBG; red pigment can be purchased from Shandong Xuanyang New Materials Co., Ltd., model: Permanent Red F2R; blue pigment can be purchased from Xingtai Caizhiyun Chemical Technology Co., Ltd., model: Phthalocyanine Blue B; black pigment can be purchased from Xingtai Caizhiyun Chemical Technology Co., Ltd., model: Pigment Carbon Black; green pigment can be purchased from Hebei Barunde Coatings Co., Ltd., model: Phthalocyanine Green G. It is understood that the above-mentioned pigment types are merely examples, and the pigment types of the present invention are not limited to the above types.

[0044] Preferably, the pigment in the printing ink is 5 to 15 parts by mass; more preferably 7 to 12 parts by mass.

[0045] Preferably, the printing ink comprises the following raw materials in parts by weight: 45-65 parts polyamide resin, 10-30 parts polyketone resin, 3-15 parts wax, 4-65 parts organic solvent, 0.2-1.5 parts dispersant, and 5-15 parts pigment.

[0046] More preferably, the printing ink comprises the following raw materials in parts by weight: 45-60 parts polyamide resin, 15-25 parts polyketone resin, 5-10 parts wax, 5-60 parts organic solvent, 0.3-1 part dispersant, and 7-12 parts pigment.

[0047] More preferably, the printing ink comprises the following raw materials in parts by weight: 45-60 parts polyamide resin, 15-25 parts polyketone resin, 5-10 parts wax, 1-20 parts methylcyclohexane, 1-15 parts ethyl acetate, 3-25 parts isopropanol, 0.3-1 parts dispersant, and 7-12 parts pigment.

[0048] Preferably, the printing ink is prepared from the following raw materials in parts by weight: 40-70 parts polyamide resin, 5-35 parts polyketone resin, 1-20 parts wax, 3-70 parts organic solvent, 0.1-2 parts dispersant, and 3-20 parts pigment.

[0049] More preferably, the printing ink is prepared from the following raw materials in parts by weight: 45-60 parts polyamide resin, 15-25 parts polyketone resin, 5-10 parts wax, 1-20 parts methylcyclohexane, 1-15 parts ethyl acetate, 3-25 parts isopropanol, 0.3-1 parts dispersant, and 7-12 parts pigment.

[0050] A second aspect of the present invention provides a method for preparing the printing ink described in the first aspect of the present invention, comprising the following steps: first mixing polyamide resin, dispersant, pigment and organic solvent, and then adding polyketone resin and wax for a second mixing to obtain the printing ink.

[0051] Preferably, in the method for preparing the printing ink, the first mixing and the second mixing are independently selected from stirring.

[0052] Preferably, in the method for preparing the printing ink, the stirring speed of the first mixing is 800-1000 r / min.

[0053] Preferably, in the method for preparing the printing ink, the stirring time for the first mixing is 30 to 50 minutes.

[0054] Preferably, the method for preparing the printing ink further includes a grinding step after the first mixing and before the second mixing.

[0055] Preferably, in the method for preparing the printing ink, the grinding temperature is 40-45°C.

[0056] Preferably, in the method for preparing the printing ink, the grinding process is performed 2 to 3 times.

[0057] Preferably, in the method for preparing the printing ink, the grinding is carried out until the fineness of the material is ≤15μm.

[0058] Preferably, in the method for preparing the printing ink, the stirring speed of the second mixing is 400-600 r / min.

[0059] Preferably, in the method for preparing the printing ink, the stirring time for the second mixing is 5 to 20 minutes.

[0060] A third aspect of the present invention provides the application of the printing ink described in the first aspect of the present invention in the fields of food packaging, cosmetic packaging, pharmaceutical packaging, or decorative products.

[0061] A fourth aspect of the present invention provides a printed article comprising a treatment-free plastic film substrate and an ink layer obtained by printing with printing ink comprising the printing ink described in the first aspect of the present invention, the ink layer being located on the surface of the treatment-free plastic film substrate.

[0062] Preferably, in the printed article, the treatment-free plastic film substrate includes at least one of PP film, PE film, OPP film, nylon film or PET film.

[0063] In the printed products of the present invention, the substrate does not need to undergo pretreatment steps such as corona treatment, and is directly printed on the substrate by printing ink. The resulting printed products have good adhesion and good wear resistance.

[0064] The beneficial effects of this invention are:

[0065] This invention, through the combined action of polyamide resin and polyketone resin, can effectively improve the adhesion of printing inks to films. It provides good adhesion without the need for pretreatment such as corona treatment of the substrate plastic film, resulting in excellent printing effects. Furthermore, it has excellent abrasion resistance, allowing printed products to withstand the wear and tear of daily use. It also boasts good durability and aesthetics, making it widely applicable in various fields such as food packaging, cosmetic packaging, pharmaceutical packaging, and decorative products.

[0066] Specifically, compared with the prior art, the present invention has the following advantages:

[0067] 1. The printing ink of the present invention dries quickly, enabling the printing to dry in a short time, thus improving production efficiency. In addition, the ink has bright and full colors, resulting in a good visual effect.

[0068] 2. The printing ink of the present invention has good adhesion and excellent wear resistance on the untreated plastic film substrate, which can meet the printing performance requirements of untreated plastic film and is applicable to different types of untreated plastic film substrates, such as polyethylene, polypropylene, nylon, etc.

[0069] 3. The printing ink of this invention does not contain harmful substances, meets the requirements of green printing, and can be widely used in various fields such as food packaging, cosmetic packaging, pharmaceutical packaging, and decorative products. Detailed Implementation

[0070] The following specific embodiments further illustrate the content of the present invention in detail. It should also be understood that the following embodiments are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art based on the principles described herein are all within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make selections within a suitable range based on the description herein, and are not intended to be limited to the specific data in the examples below. Unless otherwise specified, the raw materials, reagents, or apparatus used in the following embodiments and comparative examples can be obtained from conventional commercial sources or by existing known methods.

[0071] It should be noted that the specific information of the raw materials used in the embodiments and comparative examples of the present invention is as follows:

[0072] The dispersant is Lubrizol Solplus L300 dispersant.

[0073] The polyamide resin-1 was purchased from Anqing Hongtai New Materials Co., Ltd., and its model is HY-356 polyamide resin. The viscosity of HY-356 polyamide resin at 25℃ is 30-50 mPa·s, the softening point is 95±5℃, the amine value is ≤3, and the color measured by the iron-cobalt colorimeter is 12. The addition of HY-356 polyamide resin can significantly improve the wettability of pigments in the printing ink of this invention and significantly improve the film adhesion. It can provide good adhesion without corona treatment of the substrate plastic film.

[0074] The polyamide resin-2 was purchased from Anqing Hongtai New Materials Co., Ltd., and its model is HY-508 polyamide resin. HY-508 polyamide resin is an alcohol-soluble polyamide resin with a viscosity of 80~180mPa·s at 25℃, a softening point of 120±5℃, an amine value ≤5, and a color of 7 measured by an iron-cobalt colorimeter.

[0075] The polyamide resin-3 was purchased from Anqing Hongtai New Materials Co., Ltd., model number: HY-545 polyamide resin. HY-545 polyamide resin is an alcohol-soluble polyamide resin with good high-temperature resistance. Its viscosity at 25℃ is 100~200mPa·s, its softening point is 150±10℃, its amine value is ≤5, and its color measured by an iron-cobalt colorimeter is 7.

[0076] The polyamide resin-4 was purchased from Anqing Hongtai New Materials Co., Ltd., model number: HY-588 polyamide resin. HY-588 polyamide resin is an alcohol-soluble polyamide resin with high antifreeze properties. Its viscosity at 25℃ is 70~150mPa·s, its softening point is 100±10℃, its amine value is ≤5, and its color measured by an iron-cobalt colorimeter is 7.

[0077] The yellow pigment was purchased from Hangzhou Baihe Chemical Co., Ltd., and the model number is Permanent Yellow BHBG.

[0078] The erucamide wax powder is designated as British Croda Erucamide Wax Powder.

[0079] The polyethylene wax powder is model number Clariant 3620 polyethylene wax powder.

[0080] The polyketone resin model is Kelifu CF-120 polyketone resin.

[0081] In the embodiments and comparative examples of the present invention, the mass percentage of the polyamide resin liquid-1 formulation is: 18% methylcyclohexane, 12% ethyl acetate, 30% isopropanol, and 40% polyamide resin-1. The preparation method of the polyamide resin liquid-1 is as follows: (1) Weigh the following by mass percentage: 18% methylcyclohexane, 12% ethyl acetate, 30% isopropanol, and 40% polyamide resin-1; (2) Mix methylcyclohexane, ethyl acetate, and isopropanol evenly, then add polyamide resin-1 and stir until completely dissolved to obtain polyamide resin liquid-1.

[0082] In the embodiments and comparative examples of the present invention, the mass percentage of the polyamide resin liquid-2 formulation is: 18% methylcyclohexane, 12% ethyl acetate, 30% isopropanol, and 40% polyamide resin-2. The preparation method of the polyamide resin liquid-2 is as follows: (1) Weigh out the following by mass percentage: 18% methylcyclohexane, 12% ethyl acetate, 30% isopropanol, and 40% polyamide resin-2; (2) Mix methylcyclohexane, ethyl acetate, and isopropanol evenly, then add polyamide resin-2 and stir until completely dissolved to obtain polyamide resin liquid-2.

[0083] In the embodiments and comparative examples of the present invention, the mass percentage of the polyamide resin liquid-3 formulation is: 18% methylcyclohexane, 12% ethyl acetate, 30% isopropanol, and 40% polyamide resin-3. The preparation method of the polyamide resin liquid-3 is as follows: (1) Weigh the following by mass percentage: 18% methylcyclohexane, 12% ethyl acetate, 30% isopropanol, and 40% polyamide resin-3; (2) Mix methylcyclohexane, ethyl acetate, and isopropanol evenly, then add polyamide resin-3 and stir until completely dissolved to obtain polyamide resin liquid-3.

[0084] In the embodiments and comparative examples of the present invention, the mass percentage of the polyamide resin liquid-4 formulation is: 18% methylcyclohexane, 12% ethyl acetate, 30% isopropanol, and 40% polyamide resin-4. The preparation method of the polyamide resin liquid-4 is as follows: (1) Weigh the following by mass percentage: 18% methylcyclohexane, 12% ethyl acetate, 30% isopropanol, and 40% polyamide resin-4; (2) Mix methylcyclohexane, ethyl acetate, and isopropanol evenly, then add polyamide resin-4, and stir until completely dissolved to obtain polyamide resin liquid-4.

[0085] In the embodiments and comparative examples of the present invention, the mass percentages of the wax paste formulation are as follows: 10.5% n-propyl acetate, 56% ethyl acetate, 3.5% isopropanol, 15% erucamide wax powder, and 15% polyethylene wax powder. The preparation method of the wax paste is as follows: (1) Weigh the following by mass percentages: 10.5% n-propyl acetate, 56% ethyl acetate, 3.5% isopropanol, 15% erucamide wax powder, and 15% polyethylene wax powder; (2) Mix n-propyl acetate, ethyl acetate, and isopropanol evenly, then add erucamide wax powder and polyethylene wax powder, and stir until completely dissolved to obtain the wax paste.

[0086] In the embodiments and comparative examples of the present invention, the mass percentage of the polyketone resin liquid formulation is as follows: 35% methylcyclohexane, 10% ethyl acetate, 10% ethanol, 10% isopropanol, and 35% polyketone resin. The preparation method of the polyketone resin liquid is as follows: (1) Weigh out the following by mass percentage: 35% methylcyclohexane, 10% ethyl acetate, 10% ethanol, 10% isopropanol, and 35% polyketone resin; (2) Mix methylcyclohexane, ethyl acetate, ethanol, and isopropanol evenly, then add polyketone resin and stir until completely dissolved to obtain polyketone resin liquid.

[0087] The following description is based on specific embodiments and comparative examples.

[0088] Examples 1-7 and Comparative Examples 1-8

[0089] Examples 1-7 and Comparative Examples 1-8 each provide a printing ink for a pre-treated plastic film. The specific raw materials and their formulations are shown in Tables 1 and 2. The preparation method includes the following steps:

[0090] (1) Mix methylcyclohexane, ethyl acetate and isopropanol evenly, then add dispersant, polyamide resin liquid and pigment, adjust the stirring speed to 800-1000 rpm and continue stirring for 40 minutes;

[0091] (2) Grind the above material two to three times using a sand mill at 40 to 45°C until the fineness is ≤15μm;

[0092] (3) Add wax paste and polyketone resin liquid (not added in the comparative example), adjust the stirring speed to 400-600 rpm, stir for 10 minutes, and obtain printing ink for untreated plastic film.

[0093] Performance testing

[0094] The printing inks of Examples 1-7 and Comparative Examples 1-8 were subjected to performance testing. The specific test items and corresponding standards are as follows:

[0095] Fineness testing standard: GB / T13217.3-2022;

[0096] Solvent residue testing standard: QB / T2929-2021;

[0097] Adhesion strength testing standard: GB / T13217.7-2009;

[0098] Abrasion resistance testing standard: GB / T 7706-2008.

[0099] The test results are recorded in Tables 1 and 2.

[0100] Table 1. Raw materials and proportions (wt%) and performance test results for Examples 1-7

[0101]

[0102]

[0103] Analysis of Table 1 shows that the difference between Examples 1-5 and Comparative Example 1 is that polyketone resin liquid was added in Examples 1-5, while other materials remained the same. The addition of polyketone resin liquid improved the adhesion to the untreated plastic film substrate. Furthermore, when the amount of polyketone resin liquid added reached 15% or more, the adhesion was >95%, and when the amount reached 25%, the adhesion reached 100%.

[0104] In Examples 3, 6, and 7, the amount of polyamide resin liquid-1 was gradually increased, while other materials remained the same. As can be seen from the test results in Table 1, when 15% of the polyketone resin liquid was combined with 55% or more of the polyamide resin liquid-1, the adhesion to the untreated plastic film substrate could reach 100%.

[0105] Table 2. Raw materials and proportions (wt%) and performance test results for Comparative Examples 1–8

[0106]

[0107]

[0108] The difference between Comparative Examples 2-4 and Comparative Example 1 is that Comparative Example 1 used polyamide resin liquid-1 (HY-356 polyamide resin), while Comparative Examples 2-4 used polyamide resin liquid-2 (HY-508 polyamide resin), polyamide resin liquid-3 (HY-545 polyamide resin), and polyamide resin liquid-4 (HY-588 polyamide resin), respectively, with other materials being the same. As shown in Table 2, the adhesion strength of Comparative Example 1 reached 77%, significantly higher than the adhesion strength of Comparative Example 2 (33%), Comparative Example 3 (41%), and Comparative Example 4 (38%). This indicates that the HY-356 polyamide resin used in Comparative Example 1 exhibits excellent adhesion strength on the untreated plastic film substrate. However, due to the absence of polyketone resin liquid, its adhesion strength is still <95%, and its performance is inferior to the printing ink in the examples.

[0109] The difference between Comparative Examples 5-8 and Comparative Example 1 is that the amount of polyamide resin liquid-1 used in Comparative Example 1 is 40%, while the amounts of polyamide resin liquid-1 used in Comparative Examples 5-8 are 45%, 50%, 55%, and 60%, respectively, with other materials remaining the same. As can be seen from the test results in Table 2, the adhesion strength on the untreated plastic film substrate gradually increases with the gradual increase in the amount of polyamide resin liquid-1 used. Therefore, within the polyamide resin dosage range of this invention, printing inks with superior adhesion strength can be obtained.

[0110] Based on the test results in Tables 1 and 2, it can be seen that the printing ink for pre-treated plastic films provided by this invention, which uses polyamide resin liquid-1 (HY-356 polyamide resin), polyketone resin liquid (Kelifu CF-120 polyketone resin), and wax paste (erucamide ER wax powder and 3620 polyethylene wax powder in a 1:1 ratio), exhibits excellent adhesion and abrasion resistance on pre-treated plastic film substrates, and can meet the printing performance requirements of pre-treated plastic films.

[0111] In addition, the printing ink of the present invention has the following advantages: it does not contain harmful substances, meeting the requirements of modern green printing; it is suitable for different types of treatment-free plastic film substrates, such as polyethylene, polypropylene, nylon, etc., and has excellent adhesion, achieving good printing results; it has good abrasion resistance, able to withstand the wear and tear of daily use, ensuring the durability and aesthetics of printed materials; it dries quickly, completing the drying of printed materials in a short time, improving production efficiency; it has bright and full colors, presenting good visual effects; and it can be applied to various fields such as food packaging, cosmetic packaging, pharmaceutical packaging, and decorative products.

[0112] In summary, this invention, through the combined action of polyamide resin and polyketone resin, can effectively improve the adhesion of printing inks to films. It provides excellent adhesion and printing results without requiring pretreatment of the substrate plastic film such as corona treatment. Furthermore, it exhibits excellent abrasion resistance, allowing printed products to withstand the wear and tear of daily use. It also boasts good durability and aesthetics, making it widely applicable in various fields such as food packaging, cosmetic packaging, pharmaceutical packaging, and decorative products.

Claims

1. A printing ink for pre-treated plastic films, characterized in that, The preparation raw materials include the following parts by weight: 40-70 parts polyamide resin, 5-35 parts polyketone resin, 1-20 parts wax, 3-70 parts organic solvent, 0.1-2 parts dispersant, and 3-20 parts pigment; the polyamide resin accounts for 40-70 wt% of the total mass of the printing ink preparation raw materials; the viscosity of the polyamide resin at 25°C is 20-60 mPa·s; the softening point of the polyamide resin is 80-110°C; the amine value of the polyamide resin is ≤4; and the polyamide resin is selected from HY... 356 polyamide resin; The polyketone resin is a polymer of saturated aldehydes and saturated ketones; the hydroxyl value of the polyketone resin is 70~110 mgKOH / g; the softening point of the polyketone resin is 105~130℃; the polyketone resin is selected from CF 120 Polyketone Resin.

2. The printing ink according to claim 1, characterized in that, The wax includes erucamide wax, polyethylene wax, or a combination thereof.

3. The printing ink according to claim 1, characterized in that, The organic solvent includes at least one of methylcyclohexane, ethyl acetate, or isopropanol; And / or, the dispersant is selected from polymeric dispersants; And / or, the pigment includes at least one of white pigment, yellow pigment, red pigment, blue pigment, black pigment, or green pigment.

4. The printing ink according to any one of claims 1 to 3, characterized in that, It is prepared from the following raw materials in parts by weight: 40-70 parts polyamide resin, 5-35 parts polyketone resin, 1-20 parts wax, 3-70 parts organic solvent, 0.1-2 parts dispersant, and 3-20 parts pigment.

5. The method for preparing the printing ink according to any one of claims 1 to 4, characterized in that, Includes the following steps: The polyamide resin, dispersant, pigment and organic solvent are first mixed, and then polyketone resin and wax are added for a second mixing to obtain the printing ink.

6. The application of the printing ink according to any one of claims 1 to 4 in the fields of food packaging, cosmetic packaging, pharmaceutical packaging or decorative products.

7. A printed article, characterized in that, It includes a treatment-free plastic film substrate and an ink layer obtained by printing with printing ink according to any one of claims 1 to 4, wherein the ink layer is located on the surface of the treatment-free plastic film substrate.

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