Environment-friendly alcohol-soluble gravure inner printing ink for OPS shrink film and preparation method thereof

Abstract

The invention discloses environment-friendly alcohol-soluble gravure inner printing ink for an OPS shrink film and a preparation method of the ink. The ink is prepared from, by mass, 32.5%-35% of modified alcohol-soluble polyurethane resin liquid, 2%-3.5% of cellulose acetate butyrate liquid, 6%-6.5% of aldehyde ketone resin liquid, 55%-62.8% of color paste, 3.4%-4% of auxiliaries, 9%-30% of pigment and the balance mixed solvent. The mixed solvent is a combination of n-propyl ester, isopropanol and ethanol, and the color paste comprises fumed silica. According to the ink disclosed by the invention, the modified alcohol-soluble polyurethane resin is matched with the aldehyde ketone resin, a hydroxyl (-OH) group in the aldehyde ketone resin is utilized to generate an infiltration effect on the surface of an OPS shrink film, and an ester solvent is matched to permeate into the surface of the OPS shrink film to form occlusion, so that the adhesive force of a coating is improved; meanwhile, the cellulose acetate butyrate resin liquid with high hardness and adhesion resistance is used and matched with fumed silica with good adhesion resistance, so that the ink is quick to dry and good in film-forming property and has good adhesion resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of printing inks, and particularly to an environment-friendly alcohol-soluble intaglio printing ink for OPS shrink films and a preparation method thereof. Background Art

[0002] As is well known, halogen compounds will release toxic and harmful substances during combustion and heating, seriously threatening human health. Therefore, regulations have strictly restricted the halogen content in products. Among existing shrink film products, PVC shrink film (polyvinyl chloride heat shrink film) is unfriendly to the environment and is thus restricted from use in regions such as Europe, America, and Japan. Although PET shrink film (polyethylene terephthalate heat shrink film) is environmentally friendly and has high strength, high rigidity, and a certain shrinkage rate, it has high requirements for heat sources and is difficult to process.

[0003] With the development of market demand and technology, OPS shrink film (oriented polystyrene heat shrink film) has emerged. OPS shrink film has excellent heat shrinkage performance and transparency and is widely used in various packaging fields. In the field of lithium batteries, OPS shrink film is mainly used for the termination wrapping of diaphragms, especially suitable for the termination fixing of the winding of diaphragms of cylindrical lithium batteries, and can replace traditional PVC termination tapes. Therefore, as a new type of environmentally friendly heat shrink film replacing PVC shrink film and PET shrink film, OPS shrink film is increasingly favored by the market.

[0004] However, due to the high shrinkage rate of OPS shrink film, the corona treatment cannot be too high, otherwise it is easy to be punctured. Therefore, OPS shrink film on the market usually has a low corona treatment or is untreated, so traditional inks are difficult to adhere, and OPS shrink film is extremely easy to be dissolved by polar solvents with strong dissolving ability (such as benzene, ketone, and ester).

[0005] Therefore, it is urgent to develop an environment-friendly alcohol-soluble intaglio printing ink for OPS shrink film to solve problems such as poor adhesion when traditional inks are used for printing OPS shrink film. Summary of the Invention

[0006] The purpose of the present invention is to provide an environment-friendly alcohol-soluble intaglio printing ink for OPS shrink film, which has the characteristics of good adhesion fastness and not easy to stick, and uses alcohol solvent as the main solvent, having the advantages of safety, environmental protection, and low odor, meeting the requirements of food packaging.

[0007] To achieve the above purpose, the present invention provides the following technical solutions to be realized:

[0008] The environment-friendly alcohol-soluble intaglio printing ink for OPS shrink film, calculated by mass percentage, includes the following components:

[0009] Modified alcohol-soluble polyurethane resin solution: 32.5 - 35%, cellulose acetate butyrate solution: 2 - 3.5%, aldehyde-ketone resin solution: 6 - 6.5%, color paste: 55 - 62.8%, additives: 3.4 - 4%, pigment: 9 - 30%, and the balance is mixed solvent.

[0010] Preferably, the solid content of the modified alcohol-soluble polyurethane resin solution is 33 - 35%, the viscosity is 600 - 900 mPa.s, and the amine value is ≤ 2 mgKOH / g.

[0011] Preferably, the cellulose acetate butyrate solution, by mass percentage, comprises 20% of cellulose acetate butyrate and 80% of n-propyl acetate; the butyryl group content of the cellulose acetate butyrate is ≥ 38%, the acetyl group content is 13.5 - 15.0%, the hydroxyl group content is 1.2 - 1.5%, the molecular weight is ≥ 30,000, the Tg is ≥ 130 °C, and the melting point is 155 - 165 °C.

[0012] Preferably, the aldehyde-ketone resin solution, by mass percentage, comprises 50% of aldehyde-ketone resin and 50% of mixed solvent, the softening point of the aldehyde-ketone resin is ≥ 150 °C, the hydroxyl value is 200 - 230 mgKOH / g, and the acid value is ≤ 1.0 mgKOH / g.

[0013] Preferably, the additives include antistatic agent, polyethylene wax, and dispersant.

[0014] Preferably, the polyethylene wax is a modified polyethylene wax with high hardness and good scratch resistance, and the dispersant is an active polymer dispersant.

[0015] Preferably, the additives include fumed silica, and the percentage of fumed silica in the total mass of the ink is 1.0 - 1.3%.

[0016] Preferably, the mixed solvent is a combination of n-propyl acetate, isopropyl alcohol, and ethanol.

[0017] Preferably, the n-propyl acetate, by mass percentage, accounts for 8 - 12% of the mixed solvent.

[0018] The preparation method of the ink of the present invention comprises the following steps:

[0019] S1: Put each component in the color paste formula into a batching tank, mix evenly with a high-speed dispersing mixer, and then grind with a sand mill until the fineness is ≤ 10 μm to obtain the color paste.

[0020] S2: Mix the color paste in the ink formula with other components, disperse and stir evenly at high speed with a disperser, and after passing the inspection of each inspection index, the finished ink is obtained.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. The ink system of the present invention uses a modified alcohol-soluble polyurethane resin in combination with an aldehyde-ketone resin. The hydroxyl (-OH) groups in the aldehyde-ketone resin produce a wetting effect on the surface of the OPS shrink film, and cooperate with the ester solvent to penetrate into the surface of the OPS shrink film to form an occlusion, thereby improving the adhesion of the coating.

[0023] 2. In the ink system, a cellulose acetate butyrate resin solution with high hardness and anti-blocking property is used, and is combined with fumed silica with good anti-blocking property, so that the ink has fast drying, good film-forming property, and good anti-blocking property. It can replace the internal printing ink for traditional gravure film printing and has broad application prospects.

[0024] 3. The ink system uses alcohols as the main solvent, does not contain benzene and ketone solvents, has low odor and low solvent residue, does not contain halogens, and meets the hygiene and environmental protection requirements for packaging printing such as food and medicine, as well as the environmental protection and halogen-free standards in Europe and America. Specific Embodiments

[0025] The following will further illustrate the present invention with specific examples.

[0026] The environmental protection alcohol-soluble gravure internal printing ink for OPS shrink film, and the specific formulations of Examples 1 to 5 are shown in the following table:

[0027]

[0028] Among them, the color paste formulation is shown in the following table:

[0029]

[0030] The environmental protection alcohol-soluble gravure internal printing ink for OPS shrink film includes the following components by mass percentage:

[0031] Modified alcohol-soluble polyurethane resin solution 32.5 - 35%, cellulose acetate butyrate solution 2 - 3.5%, aldehyde-ketone resin solution 6 - 6.5%, color paste 55 - 62.8%, additives 3.4 - 4%, pigments 9 - 30%, and the balance is a mixed solvent.

[0032] Furthermore, the solid content of the modified alcohol-soluble polyurethane resin solution is 33 - 35%, the viscosity is 600 - 900 mPa·s, the amine value ≤ 2 mg KOH / g, and it has the characteristics of good alcohol solubility, light color, and good screen transfer.

[0033] Furthermore, the cellulose acetate butyrate solution, by mass percentage, includes cellulose acetate butyrate 20% and solvent (n-propyl acetate) 80%. The butyryl group content of the cellulose acetate butyrate ≥ 38%, the acetyl group content is 13.5 - 15.0%, the hydroxyl group content is 1.2 - 1.5%, the molecular weight ≥ 30000, Tg ≥ 130 °C, and the melting point is 155 - 165 °C.

[0034] Further, the aldehyde-ketone resin solution, by mass percentage, comprises 50% of aldehyde-ketone resin and 50% of solvent (mixed solvent). The softening point of the aldehyde-ketone resin is ≥150°C, the hydroxyl value is 200 - 230 mgKOH / g, and the acid value is ≤1.0 mgKOH / g.

[0035] Further, the additives include antistatic agent, polyethylene wax, and dispersant.

[0036] Further, the polyethylene wax is a modified polyethylene wax with high hardness and good scratch resistance.

[0037] Further, the dispersant is an active polymer dispersant to fully wet and disperse the pigment to achieve a full wetting effect.

[0038] Further, the fumed silica included in the additives accounts for 1.0 - 1.3% of the total mass of the ink.

[0039] Further, the mixed solvent is a combination of n-propyl acetate, isopropyl alcohol, and ethanol.

[0040] Further, the n-propyl acetate, by mass percentage, accounts for 8 - 12% of the mixed solvent. Too much will easily deform the OPS film, and too little will affect the adhesion.

[0041] The preparation method of the ink of the present invention comprises the following steps:

[0042] (1) Put each component in the color paste formula into a batching tank, mix evenly with a high-speed dispersing mixer, and then grind with a sand mill until the fineness is ≤10 μm. The grinding process is the same as that of traditional ink to obtain the color paste.

[0043] (2) Mix the color paste in the ink formula with other components, disperse and stir evenly at high speed with a disperser. After the qualified detection of each detection index, the environment-friendly alcohol-soluble gravure inks for OPS shrink films are obtained.

[0044] The environment-friendly alcohol-soluble gravure inks for OPS shrink films of Examples 1 - 5 prepared by the above method are printed on the OPS shrink film with a corona treatment of 35 dynes and then detected. The parameters of each performance index are shown in the following table:

[0045]

[0046]

[0047] In the formula of the present invention, the hydroxyl (-OH) groups in the aldehyde-ketone resin produce a wetting effect on the surface of the OPS shrink film, and a small amount (too much will easily cause deformation) of ester solvents (n-propyl acetate) penetrate into the surface of the OPS shrink film to form an occlusion, thereby improving the adhesion of the coating.

[0048] In addition, in the formulation of the present invention, cellulose acetate butyrate resin solution with high hardness and anti-sticking property is used in combination with fumed silica with good anti-sticking property, which has fast drying speed, good film-forming property, good anti-sticking property of printed products and is not prone to back sticking.

[0049] The ink technical indicators of the present invention (such as viscosity, fineness, initial dryness, adhesion fastness, total solvent residue, benzene solvent residue) meet the requirements of the standard QB / T 2024-2012.

[0050] In the technical solution provided by the present invention, the raw materials used, unless otherwise specified, are prepared by conventional means or purchased through commercial channels.

[0051] For those skilled in the art, various corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. Environmentally friendly alcohol-soluble gravure printing ink for OPS shrink film, characterized in that: By mass percentage, it includes: 32.5 - 35% of modified alcohol-soluble polyurethane resin solution, 2 - 3.5% of cellulose acetate butyrate solution, 6 - 6.5% of aldehyde-ketone resin solution, 55 - 62.8% of color paste, 3.4 - 4% of additives, 9 - 30% of pigments, and the balance is mixed solvent.

2. The environment-friendly alcohol-soluble gravure ink for OPS shrink film as described in claim 1 is characterized in that: The solid content of the modified alcohol-soluble polyurethane resin solution is 33 - 35%, the viscosity is 600 - 900 mPa·s, and the amine value is ≤2 mgKOH / g.

3. The environmentally friendly alcohol-soluble gravure inks for OPS shrink films as described in claim 1 are characterized in that: The cellulose acetate butyrate solution, by mass percentage, includes 20% of cellulose acetate butyrate and 80% of n-propyl acetate; the butyryl group content of the cellulose acetate butyrate is ≥38%, the acetyl group content is 13.5 - 15.0%, the hydroxyl group content is 1.2 - 1.5%, the molecular weight is ≥30000, Tg≥130°C, and the melting point is 155 - 165°C.

4. The environmentally friendly alcohol-soluble gravure ink for OPS shrink film as described in claim 1 is characterized in that: The aldehyde-ketone resin solution, by mass percentage, includes 50% of aldehyde-ketone resin and 50% of mixed solvent. The softening point of the aldehyde-ketone resin is ≥150°C, the hydroxyl value is 200 - 230 mgKOH / g, and the acid value is ≤1.0 mgKOH / g.

5. The environment-friendly alcohol-soluble gravure inks for OPS shrink films as claimed in claim 1, characterized in that: The additives include polyethylene wax, antistatic agent, and dispersant.

6. The environment-friendly alcohol-soluble gravure printing ink for OPS shrink film as described in claim 5, wherein: The polyethylene wax is modified polyethylene wax, and the dispersant is an active polymer dispersant.

7. The environmentally friendly alcohol-soluble gravure ink for OPS shrink film according to claim 5, wherein: The additives include fumed silica, and the percentage of fumed silica in the total mass of the ink is 1.0 - 1.3%.

8. The environmentally friendly alcohol-soluble gravure printing ink for OPS shrink film according to claim 1, characterized in that: The mixed solvent is a combination of n-propyl acetate, isopropyl alcohol, and ethanol.

9. The environmentally friendly alcohol-soluble gravure printing ink for OPS shrink film according to claim 8, wherein: The n-propyl acetate, by mass percentage, accounts for 8 - 12% of the mixed solvent.

10. A method for preparing an ink, which is used to prepare the environment-friendly alcohol-soluble intaglio printing ink for OPS shrink film as described in any one of claims 1 to 9, characterized in that, It includes the following steps: S1: Put the components in the color paste formula into a batching tank, mix them evenly with a high-speed dispersion mixer, and then grind them with a sand mill until the fineness is ≤10 μm to obtain the color paste. S2: Mix the color paste in the ink formula with other components, disperse and stir them evenly at high speed with a disperser, and after detecting that all the detection indexes are qualified, the finished ink product is obtained. ​ ​

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