Environment-friendly water-based gravure ink for automotive upholstery and preparation method thereof

Abstract

The invention relates to the technical field of ink, and discloses environment-friendly water-based gravure ink for automotive upholstery and a preparation method thereof.The preparation method comprises the steps that 2-[3-(2-(methacryloyloxy) ethyl) ureido] ethanesulfonic acid and chitosan are subjected to a graft polymerization reaction to obtain modified chitosan, the modified chitosan, pigment, a dispersing agent and the like are added into water-based acrylic resin, and the environment-friendly water-based gravure ink is prepared. The environment-friendly water-based gravure ink for the automobile interior trim parts is obtained. The modified chitosan contains a large amount of hydrophilic sulfonate groups, has excellent dispersibility in the water-based acrylic resin, is grafted with polyacrylate molecular chains, has better compatibility with the acrylic resin, and is beneficial to improving the tensile strength and mechanical properties of the ink adhesive film. The modified chitosan contains a large amount of ureido groups and can form hydrogen bond interaction force with polyurethane, polycarbonate and the like, so that the cohesiveness and adhesive force between the ink and plastic matrixes such as polyurethane, polycarbonate and the like are improved.

Description

Technical Field

[0001] The invention relates to the technical field of inks, in particular to an environmentally friendly water-based gravure ink for automobile interior decoration parts and a preparation method thereof. Background Art

[0002] Water-based acrylic resin inks offer advantages such as low VOC content, high gloss, quick drying, and easy application, making them widely used in interior and exterior wall coverings, furniture and building materials, packaging and printing. However, conventional water-based acrylic resin inks suffer from poor adhesion and bonding with plastic substrates such as polyurethane and polycarbonate, hindering their practical application in automotive interiors, plastic packaging, and other fields.

[0003] Chitosan is a natural polysaccharide derivative with excellent biocompatibility, environmental friendliness, and antibacterial properties. It has important applications in polymer materials such as acrylic resins, epoxy resins, and polyethylene. For example, the paper "Preparation and Coating Properties of Room-Temperature Self-Crosslinking Acrylic Resin-Chitosan Composite Emulsion" describes a coating prepared by cross-linking chitosan with an acrylic resin containing acetoacetoxyethyl methacrylate monomers, resulting in enhanced water absorption and tensile properties. However, this paper fails to improve the bonding and adhesion between acrylic resins and plastic substrates such as polyurethane and polycarbonate. Summary of the Invention

[0004] The invention solves the problems of poor mechanical properties of existing acrylic resin ink and low adhesion to plastic substrates such as polycarbonate.

[0005] The technical solution of the present invention is an environmentally friendly water-based gravure ink for automotive interior parts and a preparation method thereof. The ink comprises 77-84 parts by weight of a water-based acrylic resin, 2-8 parts by weight of modified chitosan, 10-14 parts by weight of a pigment, 0.8-1.3 parts by weight of a dispersant, 0.6-1 parts by weight of a leveling agent, and 0.5-0.8 parts by weight of a defoaming agent.

[0006] The preparation method comprises the following steps: adding modified chitosan, pigment, dispersant, ultrafine calcium carbonate, leveling agent and defoamer to water-based acrylic resin, stirring and mixing, grinding and discharging the material to obtain environmentally friendly water-based gravure ink for automotive interior parts.

[0007] Preferably, the preparation method of modified chitosan is:

[0008] (1) Add 2-aminoethanesulfonic acid and isocyanoethyl methacrylate in a molar ratio of (1-1.4):1 to chloroform to carry out an addition reaction, distill under reduced pressure, and recrystallize the product from an ethanol aqueous solution to obtain 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid. The preparation reaction formula is as follows:

[0009]

[0010] (2) Add chitosan to the acetic acid solution, stir to dissolve, then add the initiator, stir, add 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid, stir to react, add sodium hydroxide, then pour the solution into ethanol for precipitation, filter, wash with ethanol, and dry to obtain modified chitosan.

[0011] Preferably, the temperature of the addition reaction in (1) is 30-50° C., and the reaction time is 1.5-3 h.

[0012] Preferably, the volume fraction of the ethanol aqueous solution in (1) is 50-60%.

[0013] Preferably, the mass fraction of the acetic acid solution in (2) is 1.5-2.5%.

[0014] Preferably, the reaction temperature in (2) is 65-75° C., and the reaction time is 3-4 h.

[0015] Preferably, the mass ratio of chitosan, initiator, and 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid in (2) is 100:(0.12-0.35):(15-40).

[0016] Preferably, the initiator in (2) is potassium persulfate or ammonium persulfate.

[0017] Preferably, sodium hydroxide is added in (2) to adjust the pH of the solution to 7-8.

[0018] The beneficial technical effects of the present invention are as follows: 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid is grafted onto chitosan using potassium persulfate or the like as an initiator to produce a modified chitosan. This modified chitosan is then added to a water-based acrylic resin along with a pigment, a dispersant, and the like to produce an environmentally friendly water-based gravure ink for automotive interiors. The ink exhibits excellent dispersibility, exhibits no stratification or precipitation, and uses water as a solvent, free of organic solvents, making it environmentally friendly. The modified chitosan contains a large number of hydrophilic sulfonate groups, resulting in improved water solubility and excellent dispersibility in water-based acrylic resins. Furthermore, the modified chitosan is grafted with polyacrylate molecular chains, resulting in improved compatibility with acrylic resins. This results in the modified chitosan having a greater reinforcing effect on acrylic resin inks, thereby improving the tensile strength and mechanical properties of the ink film.

[0019] The modified chitosan of this invention contains a large number of urea groups, which can form hydrogen bonds with the carbamate groups in polyurethane and the ester groups in polycarbonate, thereby improving the bonding and adhesion between acrylic resin paint films and plastic substrates such as polyurethane and polycarbonate. This has promising practical applications in inks for automotive interior plastics. DETAILED DESCRIPTION

[0020] The following further describes the specific implementation methods of the technical solution of this specification through specific examples. These examples are for the purpose of describing the technical solution in detail, but are not intended to limit the technical solution. Based on the examples in this specification, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this specification.

[0021] The following dispersant, model HR-4133, and defoamer, model HR-8423, were purchased from Dongguan Hongrui Chemical Co., Ltd. The leveling agent, model BYK381, was purchased from Foshan Wengkaier Trading Co., Ltd. The water-based acrylic resin, model SE2954, with a water solvent and a solid content of 40%, was purchased from Foshan Wengkaier Trading Co., Ltd.

[0022] Example 1:

[0023] (1) 7 mmol of 2-aminoethanesulfonic acid and 5 mmol of isocyanoethyl methacrylate were added to 20 mL of chloroform, and the mixture was stirred at 30°C for 3 h. The mixture was distilled under reduced pressure, and the product was recrystallized from 50% by volume ethanol aqueous solution to obtain 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid.

[0024] (2) 10 g of chitosan was added to 1 L of 2% acetic acid solution, stirred to dissolve, and then 12 mg of initiator potassium persulfate was added. After stirring, 1.5 g of 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid was added. The reaction was stirred at 70°C for 3 h. Sodium hydroxide was added to adjust the pH of the solution to 8. The solution was then poured into ethanol for precipitation. After filtering, the solution was washed with ethanol and dried to obtain modified chitosan.

[0025] (3) 820 g of water-based acrylic resin, 20 g of modified chitosan, 130 g of phthalocyanine blue, 11 g of dispersant, 6 g of leveling agent, and 7 g of defoamer were stirred and mixed in a mixer, and then ground in a grinder to obtain an environmentally friendly water-based gravure ink for automotive interior parts.

[0026] Example 2:

[0027] (1) 5 mmol of 2-aminoethanesulfonic acid and 5 mmol of isocyanoethyl methacrylate were added to 15 mL of chloroform, and the mixture was stirred at 50°C for 1.5 h. The mixture was distilled under reduced pressure, and the product was recrystallized from 60% by volume ethanol aqueous solution to obtain 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid.

[0028] (2) 10 g of chitosan was added to 1 L of 1.5% acetic acid solution, stirred to dissolve, and then 23 mg of initiator ammonium persulfate was added. After stirring, 2.2 g of 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid was added. The reaction was stirred at 75°C for 3 h. Sodium hydroxide was added to adjust the pH of the solution to 7. The solution was then poured into ethanol for precipitation. After filtering, the solution was washed with ethanol and dried to obtain modified chitosan.

[0029] (3) 840 g of water-based acrylic resin, 40 g of modified chitosan, 100 g of phthalocyanine blue, 8 g of dispersant, 10 g of leveling agent, and 7 g of defoamer were stirred and mixed in a mixer, and then ground in a grinder to obtain an environmentally friendly water-based gravure ink for automotive interior parts.

[0030] Example 3:

[0031] (1) 10 g of chitosan was added to 1.2 L of 2.5% acetic acid solution, stirred and dissolved, and then 2.8 mg of potassium persulfate as an initiator was added. After stirring, 3 g of 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid (prepared in Example 1) was added. The mixture was stirred at 65° C. for 4 h. Sodium hydroxide was added to adjust the pH of the solution to 8. The solution was then poured into ethanol for precipitation. After filtering, the mixture was washed with ethanol and dried to obtain modified chitosan.

[0032] (2) 770 g of water-based acrylic resin, 60 g of modified chitosan, 140 g of phthalocyanine blue, 13 g of dispersant, 8 g of leveling agent, and 8 g of defoamer were stirred and mixed in a mixer, and then ground in a grinder to obtain an environmentally friendly water-based gravure ink for automotive interior parts.

[0033] Example 4:

[0034] (1) 10 g of chitosan was added to 1.2 L of 2% acetic acid solution, stirred and dissolved, and then 35 mg of potassium persulfate as an initiator was added. After stirring, 4 g of 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid (prepared in Example 1) was added. The mixture was stirred at 75° C. for 4 h. Sodium hydroxide was added to adjust the pH of the solution to 7. The solution was then poured into ethanol for precipitation. After filtering, the mixture was washed with ethanol and dried to obtain modified chitosan.

[0035] (2) 780 g of water-based acrylic resin, 80 g of modified chitosan, 120 g of phthalocyanine blue, 9 g of dispersant, 8 g of leveling agent, and 5 g of defoamer were stirred and mixed in a mixer, and then ground in a grinder to obtain an environmentally friendly water-based gravure ink for automotive interior parts.

[0036] Comparative Example 1: The difference between this comparative example and Example 1 is that modified chitosan is not added.

[0037] (1) 820 g of water-based acrylic resin, 130 g of phthalocyanine blue, 11 g of dispersant, 6 g of leveling agent, and 7 g of defoamer were stirred and mixed in a mixer, and then ground in a grinder to obtain an environmentally friendly water-based gravure ink for automotive interior parts.

[0038] Comparative Example 2: The difference between this comparative example and Example 1 is that chitosan is added.

[0039] (1) 820 g of water-based acrylic resin, 20 g of chitosan, 130 g of phthalocyanine blue, 11 g of dispersant, 6 g of leveling agent, and 7 g of defoamer were stirred and mixed in a mixer, and then ground in a grinder to obtain an environmentally friendly water-based gravure ink for automotive interior parts.

[0040] Comparative Example 3: The difference between this comparative example and Example 1 is that, when preparing the modified chitosan, methyl methacrylate is used instead of 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid.

[0041] (1) Add 10 g of chitosan to 1 L of 2% acetic acid solution, stir to dissolve, then add 12 mg of initiator potassium persulfate, stir, then add 1.5 g of methyl methacrylate, stir and react at 70°C for 3 h, add sodium hydroxide to adjust the pH of the solution to 8, then pour the solution into ethanol for precipitation, filter, wash with ethanol, and dry to obtain modified chitosan.

[0042] (2) 820 g of water-based acrylic resin, 20 g of modified chitosan, 130 g of phthalocyanine blue, 11 g of dispersant, 6 g of leveling agent, and 7 g of defoamer were stirred and mixed in a mixer, and then ground in a grinder to obtain an environmentally friendly water-based gravure ink for automotive interior parts.

[0043] Comparative Example 4: The difference between this comparative example and Example 1 is that when preparing modified chitosan, sodium 2-ethyl methacrylate (structural formula: CAS registration number 1804-87-1) salt instead of 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid.

[0044] (1) Add 10 g of chitosan to 1 L of 2% acetic acid solution, stir to dissolve, then add 12 mg of initiator potassium persulfate, stir, then add 1.5 g of 2-ethanesulfonic acid methacrylate sodium salt, stir and react at 70°C for 3 h, add sodium hydroxide to adjust the pH of the solution to 8, then pour the solution into ethanol for precipitation, filter, wash with ethanol, and dry to obtain modified chitosan.

[0045] (2) 820 g of water-based acrylic resin, 20 g of modified chitosan, 130 g of phthalocyanine blue, 11 g of dispersant, 6 g of leveling agent, and 7 g of defoamer were stirred and mixed in a mixer, and then ground in a grinder to obtain an environmentally friendly water-based gravure ink for automotive interior parts.

[0046] The ink was placed at room temperature for 6 months and the dispersion was observed.

[0047] The ink was poured into a mold and cured at 80°C for 15 hours to form a film. The tensile strength was tested according to the method of GB / T 1040.1-2018.

[0048] Spray the ink onto the surface of a polyurethane plastic substrate or a polycarbonate plastic substrate, bake and cure at 80°C for 12 hours, and test the ink adhesion A according to the method in GB / T 13217.7-2023.

[0049] A = A1 / (A1+A2) x 100%. A1 is the number of ink film cells remaining on the substrate after the tape is removed. A2 is the number of ink film cells removed.

[0050] Table 1 Ink performance test

[0051]

[0052]

[0053] After testing, compared with the acrylic resin ink of Comparative Example 1, the inks of Examples 1-4 have higher tensile strength and mechanical properties, and their adhesion to plastic substrates such as polyurethane and polycarbonate is significantly improved. This is mainly because the modified chitosan added is grafted with polyacrylate molecular chains, which has better compatibility with acrylic resin. At the same time, the modified chitosan contains a large number of hydrophilic sulfonate groups, which improves water solubility and excellent dispersibility in water-based acrylic resin. As a result, the modified chitosan has a better reinforcing effect on the acrylic resin ink, which is beneficial to improving the tensile strength of the ink film. In addition, the modified chitosan contains a large number of urea groups (-NH-C=O-NH), which can form hydrogen bond interactions with the carbamate groups in polyurethane and the ester groups in polycarbonate, thereby improving the bonding and adhesion between the acrylic resin paint film and plastic substrates such as polyurethane and polycarbonate.

[0054] In Comparative Example 2, only chitosan was added, which has poor water solubility, poor dispersibility in water-based acrylic resin, and poor compatibility with acrylic resin, resulting in low tensile strength of the ink film and reduced adhesion to polyurethane and polycarbonate. This may be because chitosan has poor dispersibility in water-based acrylic resin and is easy to agglomerate, affecting the leveling and flatness of the film surface, resulting in reduced adhesion.

[0055] Comparative Example 3, in which chitosan was grafted with methyl methacrylate, resulted in a modified chitosan lacking hydrophilic sulfonate groups, resulting in poor water solubility and dispersibility in aqueous acrylic resins, with noticeable precipitation and reduced ink dispersibility. Furthermore, the modified chitosan lacked urea groups, resulting in weak hydrogen bonding interactions with polyurethane and polycarbonate, making it difficult to effectively improve the bonding and adhesion between acrylic resin films and plastic substrates such as polyurethane and polycarbonate.

[0056] Comparative Example 4: Chitosan was grafted and modified with sodium methacrylate 2-ethanesulfonate. The obtained modified chitosan did not contain urea groups, and the hydrogen bond interaction force between polyurethane and polycarbonate was low, making it difficult to effectively improve the bonding and adhesion between the acrylic resin paint film and plastic matrices such as polyurethane and polycarbonate.

Claims

1. An environmentally friendly water-based gravure ink for automotive interior parts, characterized in that: The water-based gravure ink comprises 77-84 parts by weight of water-based acrylic resin, 2-8 parts by weight of modified chitosan, 10-14 parts by weight of pigment, 0.8-1.3 parts by weight of dispersant, 0.6-1 parts by weight of leveling agent, and 0.5-0.8 parts by weight of defoamer; The preparation method of the modified chitosan comprises the following steps: adding chitosan to an acetic acid solution, stirring and dissolving the chitosan, adding an initiator, stirring and then adding 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid, stirring and reacting the solution, adding sodium hydroxide, and then pouring the solution into ethanol for precipitation, filtering, washing, and drying to obtain the modified chitosan.

2. The environmentally friendly water-based gravure ink for automotive interior parts according to claim 1, characterized in that: The mass fraction of the acetic acid solution is 1.5-2.5%.

3. The environmentally friendly water-based gravure ink for automotive interior parts according to claim 1, characterized in that: The reaction temperature is 65-75° C., and the reaction time is 3-4 hours.

4. The environmentally friendly water-based gravure ink for automotive interior parts according to claim 1, characterized in that: The solution pH is adjusted to 7-8 by adding sodium hydroxide.

5. The environmentally friendly water-based gravure ink for automotive interior parts according to claim 1, characterized in that: The mass ratio of the chitosan, the initiator, and the 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid is 100:(0.12-0.35):(15-40).

6. The environmentally friendly water-based gravure ink for automotive interior parts according to claim 5, characterized in that: The initiator is potassium persulfate or ammonium persulfate.

7. The environmentally friendly water-based gravure ink for automotive interior parts according to claim 5, characterized in that: The preparation method of 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid comprises: adding 2-aminoethanesulfonic acid and isocyanoethyl methacrylate in a molar ratio of (1-1.4):1 to chloroform, carrying out an addition reaction, performing reduced pressure distillation, and recrystallizing the product to obtain 2-[3-(2-(methacryloyloxy)ethyl)ureido]ethanesulfonic acid.

8. The environmentally friendly water-based gravure ink for automotive interior parts according to claim 7, characterized in that: The temperature of the addition reaction is 30-50° C., and the reaction time is 1.5-3 hours.

9. The environmentally friendly water-based gravure ink for automotive interior parts according to claim 7, characterized in that: The volume fraction of the ethanol aqueous solution is 50-60%.

10. A method for preparing the environmentally friendly water-based gravure ink for automobile interior decoration according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: adding modified chitosan, pigment, dispersant, ultrafine calcium carbonate, leveling agent and defoamer to water-based acrylic resin, stirring and mixing, grinding and discharging the material to obtain environmentally friendly water-based gravure ink for automobile interior decoration parts.

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