阅读说明：本技术 一种在收缩薄膜上印刷水性油墨的方法 (Method for printing water-based ink on shrink film ) 是由 吴伟忠 陈振权 陈立 王丽芬 于 2020-12-23 设计创作，主要内容包括：本发明属于印刷材料的制备技术领域,公开了一种在收缩薄膜上印刷水性油墨的方法。该方法包括以下步骤：(1)将水性油墨与稀释剂混合,搅拌,过滤,得滤液,将带有凹槽的印刷版浸入滤液中；(2)然后刮去印刷版的平整部分的水性油墨,再将收缩薄膜压在印刷版上,取出收缩薄膜,印刷保护层材料,烘干；保护层材料包括硝化棉、酯酸、助剂和溶剂。通过对印制工艺的优化,以及在收缩薄膜印刷油墨后涂覆保护层材料,使印刷得到的收缩薄膜中油墨的附着牢度高,耐摩擦性能优异。经测试,收缩薄膜油墨脱落面积低于10％,耐摩擦次数高达125次。(The invention belongs to the technical field of preparation of printing materials, and discloses a method for printing water-based ink on a shrink film. The method comprises the following steps: (1) mixing the water-based ink with a diluent, stirring and filtering to obtain filtrate, and immersing the printing plate with the groove into the filtrate; (2) scraping off the water-based ink on the flat part of the printing plate, pressing the shrink film on the printing plate, taking out the shrink film, printing a protective layer material, and drying; the protective layer material comprises nitrocotton, ester acid, an auxiliary agent and a solvent. By optimizing the printing process and coating a protective layer material after the ink is printed on the shrink film, the adhesion fastness of the ink in the printed shrink film is high, and the friction resistance is excellent. Tests show that the dropping area of the ink of the shrink film is less than 10 percent, and the rubbing resistant times are as high as 125 times.)

1. A method of printing a water-based ink on a shrink film, comprising the steps of:

(1) mixing the water-based ink with a diluent, stirring and filtering to obtain filtrate, and immersing the printing plate with the groove into the filtrate;

(2) scraping off the water-based ink on the flat part of the printing plate, pressing the shrink film on the printing plate, taking out the shrink film, printing a protective layer material, and drying;

the protective layer material comprises nitrocotton, ester acid, an auxiliary agent and a solvent.

2. The method according to claim 1, wherein the protective layer material comprises 10-30 parts by weight of nitrocotton, 10-30 parts by weight of ester acid, 1-5 parts by weight of an auxiliary agent and 50-70 parts by weight of a solvent.

3. The method according to claim 1 or 2, characterized in that the preparation of the protective layer material comprises the following steps: mixing nitrocotton, ester acid, an auxiliary agent and a solvent, grinding, filtering, and taking filtrate to obtain the protective layer material.

4. The method of claim 2, wherein the protective layer material has a viscosity of: the outflow time of No. 3 cup at 25 deg.C is 13-20 seconds.

5. The method according to claim 1, wherein in step (1), the viscosity of the aqueous ink is: the outflow time of No. 3 cup at 25 deg.C is 10-20 seconds.

6. The method according to claim 1, wherein in the step (1), the aqueous ink comprises the following components in parts by weight: 10-30 parts of water, 10-30 parts of ethanol, 32-38 parts of waterborne polyurethane resin and 11-13 parts of pigment.

7. The method according to claim 1, wherein in the step (1), the ratio of the amount of the aqueous ink to the amount of the diluent is 1: (0.8-1.2).

8. The method of claim 1, wherein in step (2), the shrink film is selected from one of a polyester film, a polystyrene shrink film, or a polyvinyl chloride shrink film.

9. A shrink film produced by the method of any one of claims 1-8, comprising a protective layer having a thickness of 20-50 μm.

10. Use of the method of any one of claims 1-8 in the manufacture of packaging material.

Technical Field

The invention belongs to the technical field of preparation of printing materials, and particularly relates to a method for printing water-based ink on a shrink film.

Background

The current gravure printing heat-shrinkable film is printed by solvent ink, the ink and the thinner still need to use a large amount of volatile organic solvents such as ester, ether, n-propyl ester, isopropanol, n-propanol and the like, and a large amount of VOCs (volatile organic compounds) are generated during printing, so that the gravure printing heat-shrinkable film is not beneficial to environmental protection; production workers can seriously damage the nervous system and seriously affect the body health under the working environment full of volatile organic chemical substances for a long time; the residue or migration of solvent in solvent ink (containing a large amount of organic solvent) on the product packaging also causes problems of hygiene, safety, etc. It is imperative that solvent inks be replaced with aqueous inks (inks in which water is used instead of organic solvents).

However, the water-based ink has poor solubility and poor stability compared with the oil-based solvent ink; and the thickness of the shrink film is small, the thickness of the required coating is small, and a shrink process such as thermal shrinkage is required during use, so that higher requirements are provided for the printing process of the water-based ink.

At present, the problems of low adhesion fastness, easy shedding, weak friction resistance and the like of a shrink film printed by water-based ink generally exist, and the quality of printed matters cannot meet the requirements.

Therefore, it is desirable to provide a method for printing water-based ink on a shrink film, which can provide a shrink film having high ink adhesion and excellent rub resistance.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art described above. Therefore, the invention provides a method for printing water-based ink on a shrink film, and the shrink film obtained by printing has high ink adhesion and excellent friction resistance.

A method of printing an aqueous ink on a shrink film comprising the steps of:

(1) mixing the water-based ink with a diluent, stirring and filtering to obtain filtrate, and immersing the printing plate with the groove into the filtrate;

(2) scraping off the water-based ink on the flat part of the printing plate (the printing plate consists of the flat part and the groove), pressing the shrink film on the printing plate, taking out the shrink film, printing a protective layer material, and drying;

the protective layer material comprises nitrocotton, ester acid, an auxiliary agent and a solvent.

Preferably, the protective layer material comprises 10-30 parts of nitrocotton, 10-30 parts of ester acid, 1-5 parts of an auxiliary agent and 50-70 parts of a solvent.

Preferably, the ester acid is butyl acetate acid and its salt, propyl acetate acid and its salt, and ethyl acetate acid and its salt.

Preferably, the auxiliary agent is selected from at least one of a stabilizer, an antioxidant, a flame retardant, a foaming agent, an antistatic agent, a mildewproof agent or a lubricant.

Further preferably, the auxiliary agent is wax and silicone oil.

Nitrocotton and ester acid are used as protective layer materials, the film formed by the nitrocotton has high elasticity, and the toughness and the friction resistance of the film layer are enhanced by matching with the ester acid; meanwhile, the components have good compatibility and can be quickly compatible and attached with the water-based ink; in the film shrinkage process, especially the thermal shrinkage process, the film is formed quickly and is tightly combined with the printing ink, so that the printing ink can be effectively prevented from falling off.

Preferably, the preparation method of the protective layer material comprises the following steps:

preferably, the preparation method of the protective layer material comprises the following steps: weighing nitrocotton, ester acid, an auxiliary agent and a solvent, mixing, grinding and filtering to obtain a filtrate, namely the protective layer material.

Specifically, nitrocotton, ester acid, an auxiliary agent and a solvent are weighed, mixed uniformly and then introduced into a sand mill, and grinding is carried out by using grinding beads with the particle size of 0.1-0.8mm until the particle size is 10-100 nm; filtering with 0.35 μm PP filter membrane to obtain filtrate as the protective layer material.

Further preferably, the viscosity of the protective layer material is: the outflow time of No. 3 cup at 25 deg.C is 13-20 seconds. The viscosity of the protective layer material is adjusted to be basically consistent with that of the water-based ink, so that film forming and tight combination are facilitated.

Preferably, in the step (1), the viscosity of the aqueous ink is: the outflow time of No. 3 cup is 10-20 seconds at 25 ℃; more preferably, in the step (1), the viscosity of the aqueous ink is: the outflow time of No. 3 cup at 25 deg.C is 13-20 seconds.

Preferably, the ratio of the water-based ink to the diluent in the step (1) is 1: (0.8-1.2).

Preferably, the aqueous ink in the step (1) comprises the following components in parts by weight: 10-30 parts of water, 10-30 parts of ethanol, 32-38 parts of waterborne polyurethane resin and 11-13 parts of pigment.

The pigment is nano calcium carbonate or nano carbon black and water-based color pigment.

Preferably, in step (1), the diluent is ethanol and/or water.

Preferably, in step (1), the stirring process is performed at a stirring speed of 40-50 rpm.

Preferably, a filter screen is adopted for filtering in the step (1), and the mesh number of the filter screen is 80-120 meshes.

Preferably, in the step (1), the thickness of the sprayed aqueous ink on the printing plate is 30-40 μm.

Preferably, in the step (1), the thickness of the protective layer material is 20-50 μm; further preferably, the thickness of the protective layer material is 30-50 μm.

Preferably, the shrink film in the step (2) is selected from one of a polyester film (PETG), a polystyrene shrink film (OPS) or a polyvinyl chloride shrink film (PVC), wherein the polyester film is of a unidirectional heat shrink type, the polystyrene shrink film is of an oriented stretch type, and the polyvinyl chloride shrink film is of a heat shrink type, and has good adaptability to the printing method.

The pressure of the shrink film pressed on the printing plate in the step (2) is 0.1-0.3MPa, and the time of pressing the shrink film on the printing plate is 0.1-1 second.

The method is applied to the preparation of packaging materials.

A packaging material is prepared by the method.

Compared with the prior art, the invention has the following beneficial effects:

according to the method, the printing process is optimized, and the protective layer material is coated after the ink is printed on the shrink film, so that the adhesion fastness of the ink in the printed shrink film is high, and the friction resistance is excellent. Tests show that the ink dropping area of the shrink film is less than 10%, and the rubbing resistance times are more than 100 times and up to 125 times.

Detailed Description

In order to make the technical solutions of the present invention more apparent to those skilled in the art, the following examples are given for illustration. It should be noted that the following examples are not intended to limit the scope of the claimed invention.

The starting materials, reagents or apparatuses used in the following examples are conventionally commercially available or can be obtained by conventionally known methods, unless otherwise specified.

Example 1

A method of printing an aqueous ink on a shrink film comprising the steps of:

(1) before use, the WB series water-based ink is stirred sufficiently to be uniform, and the viscosity of the water-based ink is 15 seconds (Zhen En cup No. 3). The water-based ink and the water are slowly added into the water-based ink under the condition of stirring according to the dosage ratio of 1:1, and a large amount of quick addition is avoided. The ink is stirred at a stirring speed of 50 revolutions per minute, and is filtered by a filter screen, wherein the mesh number of the filter screen is 90. The printing ink is transferred to a printing roller soaked in the printing ink and stored on the printing roller with the groove, and the thickness of the water-based printing ink on the printing roller is 40 mu m;

(2) scraping off water-based ink on the flat part of a printing plate roller (the printing plate consists of the flat part and a groove), and then impressing the ink on the printing plate roller on a one-way thermal shrinkage polyester film (PETG) at the pressure of 0.1MPa for 0.1 second; and taking out the shrink film, printing a protective layer material, and drying the film at 60 ℃ for 0.8 second. The thickness of the protective layer was 20 μm.

The preparation method of the printing protective layer material comprises the following steps: weighing 20kg of nitrocotton, 20kg of propyl propionate, 1kg of wax, 1kg of silicone oil (lubricant) and 58kg of ethanol, uniformly mixing, introducing into a sand mill, and grinding to a particle size of 10-100nm by using grinding beads with the particle size of 0.1-0.8 mm; filtering with 0.35 μm PP filter membrane to obtain filtrate as protective layer material.

Example 2

A method of printing an aqueous ink on a shrink film comprising the steps of:

(1) before use, the WB series water-based ink is stirred sufficiently to be uniform, and the viscosity of the water-based ink is 15 seconds (Zhen En cup No. 3). The dosage ratio of the water-based ink to the 90% ethanol solution is 1:1, the 90% ethanol solution is slowly added into the water-based ink under the condition of stirring, and a large amount of quick addition is avoided. The ink is stirred at a stirring speed of 50 revolutions per minute, and is filtered by a filter screen, wherein the mesh number of the filter screen is 90. The printing ink is transferred to a printing roller soaked in the printing ink and stored on the printing roller with the groove, and the thickness of the water-based printing ink on the printing roller is 45 mu m;

(2) scraping off water-based ink on the flat part of a printing plate roller (the printing plate consists of the flat part and a groove), and then impressing the ink on the printing plate roller on a one-way thermal shrinkage polyester film (PETG) at the pressure of 0.1MPa for 0.1 second; and taking out the shrink film, printing a protective layer material, and drying the film at 60 ℃ for 0.8 second. The thickness of the protective layer was 45 μm.

The preparation method of the printing protective layer material comprises the following steps: weighing 20kg of nitrocotton, 20kg of propyl propionate, 1kg of wax, 1kg of silicone oil (lubricant) and 58kg of ethanol, uniformly mixing, introducing into a sand mill, and grinding to a particle size of 10-100nm by using grinding beads with the particle size of 0.1-0.8 mm; filtering with 0.35 μm PP filter membrane to obtain filtrate as protective layer material.

Example 3

A method of printing an aqueous ink on a shrink film comprising the steps of:

(1) before use, the KB series water-based ink is stirred sufficiently to be uniform, and the viscosity of the water-based ink is 15 seconds (Zhen En cup No. 3). The water-based ink and the water are slowly added into the water-based ink under the condition of stirring according to the dosage ratio of 1:1, and a large amount of quick addition is avoided. The ink is stirred at a stirring speed of 50 revolutions per minute, and is filtered by a filter screen, wherein the mesh number of the filter screen is 90. The printing ink is transferred to a printing roller soaked in the printing ink and stored on the printing roller with the groove, and the thickness of the water-based printing ink on the printing roller is 40 mu m;

(2) scraping off water-based ink on the flat part of a printing plate roller (the printing plate consists of the flat part and a groove), and then impressing the ink on the printing plate roller on a polyvinyl chloride (PVC) heat-shrinkable film under the pressure of 0.1MPa for 0.1 second; and taking out the shrink film, printing a protective layer material, and drying the film at 60 ℃ for 0.8 second. The thickness of the protective layer was 30 μm.

The preparation method of the printing protective layer material comprises the following steps: weighing 20kg of nitrocotton, 20kg of propyl propionate, 1kg of wax, 1kg of silicone oil (lubricant) and 58kg of ethanol, uniformly mixing, introducing into a sand mill, and grinding to a particle size of 10-100nm by using grinding beads with the particle size of 0.1-0.8 mm; filtering with 0.35 μm PP filter membrane to obtain filtrate as protective layer material.

Example 4

A method of printing an aqueous ink on a shrink film comprising the steps of:

(1) before use, the WB series water-based ink is stirred sufficiently to be uniform, and the viscosity of the water-based ink is in a range of 13 seconds (TanTsu cup No. 3). The water-based ink and the water are slowly added into the water-based ink under the condition of stirring according to the dosage ratio of 1:0.8, and a large amount of quick addition is avoided. The ink is stirred at a stirring speed of 50 revolutions per minute, and is filtered by a filter screen, wherein the mesh number of the filter screen is 90. The printing ink is transferred to a printing roller soaked in the printing ink and stored on the printing roller with the groove, and the thickness of the water-based printing ink on the printing roller is 40 mu m; the thickness of the protective layer was 10 μm.

(2) Scraping off water-based ink on the flat part of a printing plate roller (the printing plate consists of the flat part and a groove), and then impressing the ink on the printing plate roller on a one-way thermal shrinkage polyester film (PETG) at the pressure of 0.1MPa for 0.1 second; and taking out the shrink film, printing a protective layer material, and drying the film at 60 ℃ for 0.8 second.

The preparation method of the printing protective layer material comprises the following steps: weighing 10kg of nitrocotton, 30kg of propyl propionate, 1kg of wax, 1kg of silicone oil (lubricant) and 60kg of ethanol, uniformly mixing, introducing into a sand mill, and grinding to a particle size of 10-100nm by using 0.1-0.8mm grinding beads; filtering with 0.35 μm PP filter membrane to obtain filtrate as protective layer material.

Example 5

A method of printing an aqueous ink on a shrink film comprising the steps of:

(1) before use, the WB series water-based ink is stirred sufficiently to be uniform, and the viscosity of the water-based ink is 20 seconds (Shi En cup No. 3). The use amount ratio of the water-based ink to the ethanol is 1:1.2, the ethanol is slowly added into the water-based ink under the stirring condition, and a large amount of rapid addition is avoided. The ink is stirred at a stirring speed of 50 revolutions per minute, and is filtered by a filter screen, wherein the mesh number of the filter screen is 90. The printing ink is transferred to a printing roller soaked in the printing ink and stored on the printing roller with the groove, and the thickness of the water-based printing ink on the printing roller is 40 mu m;

(2) scraping off water-based ink on the flat part of a printing plate roller (the printing plate consists of the flat part and a groove), and then impressing the ink on the printing plate roller on a one-way thermal shrinkage polyester film (PETG) at the pressure of 0.1MPa for 0.1 second; taking out the shrink film, printing a protective layer material, and drying the film at 55-60 ℃ for 0.8 second. The thickness of the protective layer was 20 μm.

The preparation method of the printing protective layer material comprises the following steps: weighing 30kg of nitrocotton, 10kg of propyl ester acid, 1kg of wax, 2kg of silicone oil (lubricant) and 55kg of ethanol, uniformly mixing, introducing into a sand mill, and grinding to the particle size of 10-100nm by using 0.1-0.8mm grinding beads; filtering with 0.35 μm PP filter membrane to obtain filtrate as protective layer material.

Example 6

A method of printing an aqueous ink on a shrink film comprising the steps of:

(1) before use, the mixture should be stirred sufficiently to make the water-based ink in the barrel uniform, and the viscosity of the water-based ink is in a range of 15 seconds (Zhen En cup No. 3). The water-based ink and the water are slowly added into the water-based ink under the condition of stirring according to the dosage ratio of 1:1, and a large amount of quick addition is avoided. The ink is stirred at a stirring speed of 50 revolutions per minute, and is filtered by a filter screen, wherein the mesh number of the filter screen is 90. The printing ink is transferred to a printing roller soaked in the printing ink and stored on the printing roller with the groove, and the thickness of the water-based printing ink on the printing roller is 40 mu m;

the water-based ink comprises the following components in parts by weight: 20 parts of water, 20 parts of ethanol, 35 parts of waterborne polyurethane resin and 12 parts of pigment; the pigment is nano calcium carbonate or nano carbon black. The water-based ink can be provided by Beijing Korea science and technology development Co.

(2) Scraping off water-based ink on the flat part of a printing plate roller (the printing plate consists of the flat part and a groove), and then impressing the ink on the printing plate roller on a one-way thermal shrinkage polyester film (PETG) at the pressure of 0.1MPa for 0.1 second; and taking out the shrink film, printing a protective layer material, and drying the film at 60 ℃ for 0.8 second. The thickness of the protective layer was 30 μm.

The preparation method of the printing protective layer material comprises the following steps: weighing 20kg of nitrocotton, 20kg of propyl propionate, 1kg of wax, 1kg of silicone oil (lubricant) and 58kg of ethanol, uniformly mixing, introducing into a sand mill, and grinding to a particle size of 10-100nm by using grinding beads with the particle size of 0.1-0.8 mm; filtering with 0.35 μm PP filter membrane to obtain filtrate as protective layer material.

Example 7

The viscosity number of the aqueous ink in example 7 was 25 seconds as compared to example 1, and the rest of the preparation was the same as example 1.

Example 8

Compared with example 1, the material for the protective layer in example 8 was prepared from 5kg of nitrocotton, 35kg of propionic acid, 1kg of wax, 1kg of silicone oil (lubricant) and 58kg of ethanol, and the remaining preparation process was the same as in example 1.

Comparative example 1

In comparison with example 1, the protective layer was not printed in step (2) of comparative example 1, and the remaining preparation process was the same as example 1.

Comparative example 2

In comparison with example 1, propylpropionate in the protective layer material of step (2) of comparative example 2 was replaced with propionic acid, and the rest of the preparation process was the same as in example 1.

Product effectiveness testing

(1) The prints prepared in examples 1 to 8 and comparative examples 1 to 2 were used for ink adhesion comparison. The adhesion fastness of the water-based ink in the printed matter is detected by adopting a method of detecting an adhesive tape (the model of the adhesive tape is 3M600 or 810), the adhesive tape is placed for 2 hours after printing and then detected, the water-based ink attached to the surface of the printed matter by the adhesive tape is detected, and after the adhesive tape is torn off, the printed matter is normal in color fastness or the color fading area is less than 10%. And calculating the falling area ratio of the water-based ink, wherein the smaller the falling area ratio of the water-based ink is, the better the adhesion fastness of the water-based ink is.

(2) The prints prepared in examples 1 to 8 and comparative examples 1 to 2 were subjected to a rub resistance test for comparison. The anti-friction performance of the water ink in the printed matter adopts an arc anti-friction tester, the printing surface of the test material is rubbed against the unprinted film at a friction speed of 30 times/min (1 time for reciprocation), a weight of 300g is placed on the rubbing head, and the printed matter is qualified without obvious fading for more than 100 times of rubbing. The number of rubs without significant discoloration was recorded.

The print test results are shown in table 1.

Table 1: printed matter test results

As can be seen from Table 1, the adhesion of the water-based inks on the surfaces of the prints prepared in examples 1 to 8 of the present invention is significantly better than the adhesion of the water-based inks on the surfaces of the prints prepared in comparative examples 1 to 2. The surface water-based ink adhesion of the printed matter added with the protective layer provided by the invention is obviously better than that of the printed matter without adding or changing the formula. Meanwhile, the water-based ink friction resistance of the surfaces of the printed matters prepared in examples 1-8 of the invention is obviously better than that of the surfaces of the printed matters prepared in comparative examples 1-2.