Ink composition and preparation method thereof

Abstract

The present application relates to paper-based printing, and discloses an ink composition and a preparation method thereof. The ink composition comprises the following raw materials in parts by weight: 1 to 40 parts of color paste, 60 to 100 parts of ink resin emulsion, 0.1 to 1 part of ink defoamer, 3 to 10 parts of regulator, 0.2 to 0.5 parts of ammonia water, 4 to 5.5 parts of polyol phosphate, and 8.7 to 11.8 parts of auxiliary agent A; the ink resin emulsion is a polyacrylate emulsion, and the relative molecular weight of the resin is greater than 200,000; the relative molecular weight of the ink defoamer is within 7,000 to 15,000, and the regulator is compounded with ethanol and water; the auxiliary agent A is compounded with sodium aluminate and sodium citrate. The ink composition of the present application, without using an existing wetting and dispersing agent, not only reduces the possibility of ink penetration in thin packaging paper, but also ensures the uniformity and adhesion of printing, and reduces the defective rate.

Description

Technical Field

[0001] The present application relates to paper-based printing, and more particularly to an ink composition and a preparation method thereof. Background Art

[0002] Due to technological innovation, the minimum thickness of packaging paper is getting thinner while ensuring the strength required for packaging, which is of great benefit to cost reduction and environmental protection. Extending to the field of paper-based printing, new improvement requirements are also put forward for ink selection and printing process.

[0003] The penetration performance of existing inks is targeted at the thickness of the original wrapping paper. When the existing inks are directly applied to thinner wrapping paper, the ink's penetration performance is too strong, and the inorganic pigment particles in the ink easily penetrate or permeate the thin wrapping paper excessively, resulting in irregular and difficult-to-control pattern coloring on the back of the thin wrapping paper, which makes the printing appearance of the wrapping paper criticized, and there are also safety issues when packaging items or foods with high safety requirements such as straws.

[0004] Therefore, developing an ink composition to better cope with the printing needs brought about by the increasingly thin and light packaging paper - the ink can easily penetrate through the packaging paper, which has become one of the important development directions of packaging paper printing. Summary of the invention

[0005] In order to solve the problem that the current ink easily penetrates through the packaging paper as the packaging paper becomes thinner and lighter, an ink composition and a preparation method thereof are provided.

[0006] The first above-mentioned invention objective of the present invention is achieved through the following technical solutions:

[0007] An ink composition comprises the following raw materials in parts by mass: 1-40 parts of color paste, 60-100 parts of ink resin emulsion, 0.1-1 parts of ink defoamer, 3-10 parts of regulator, 0.2-0.5 parts of ammonia water, 4-5.5 parts of polyol phosphate, and 8.7-11.8 parts of auxiliary agent A; the ink resin emulsion is a polyacrylate emulsion, and the relative molecular weight of the resin is greater than 200000; the relative molecular weight of the ink defoamer is within 7000-15000; the regulator is compounded with ethanol and water; and the auxiliary agent A is compounded with sodium aluminate and sodium citrate.

[0008] Currently, wetting and dispersing agents are often added to printing inks to disperse the pigment particles in the color paste. Wetting and dispersing agents are mostly modified polyesters with anionic properties. They carry a negative charge in the aqueous medium, thus interacting with the positively charged inorganic pigment particles to disperse the inorganic pigment particles.

[0009] On the other hand, this type of wetting dispersant liquid has better permeability to paper. It will quickly penetrate the paper. For thin packaging paper, it will swell the paper fibers and aggravate the excessive penetration or penetration of inorganic pigment particles into the thin packaging paper. Therefore, the wetting dispersant is one of the reasons for the color development problem on the back of thin packaging paper.

[0010] By adopting the above technical solution, the present application is improved from the direction of lubricating dispersant, and does not use the modified polyester wetting dispersant with anionic characteristics. The relative molecular weight of the ink defoamer used is 7000-15000, and the relative molecular weight of the resin of the ink resin emulsion is greater than 200000. The high molecular weight ink defoamer and resin are dispersed and coated on the outside of the inorganic pigment particles, which reduces the penetration of the inorganic pigment particles into the paper substrate and improves the safety of the packaging paper.

[0011] At the same time, a water-ethanol mixed regulator is used, and active hydroxyl groups are introduced with ethanol, so that the high molecular weight ink defoamer and ink resin can maintain short-term (4-10 hours) uniform dispersion after the ink composition is stirred before use, providing a sufficient printing working window period, and the ethanol evaporates quickly during the printing process, and the solid matter in the initial ink composition flows adaptively to the tension of the printing liquid film, forming a more uniform and dense cured film;

[0012] Polyol phosphates can improve the adhesion of ink compositions;

[0013] The ink composition of the present application contains ethanol, ammonia, water, and easily hydrolyzed silane, so the ink drying speed varies greatly at different working environment temperatures, and the ink composition undergoes different decomposition conditions at different storage temperatures, which correspondingly affects the pH of the ink composition, thereby causing problems such as premature cross-linking of the resin in the ink composition, premature cross-linking of the siloxane, and agglomeration of inorganic pigment particles. In this regard, sodium aluminate and sodium citrate are added as a group of buffers to mitigate the storage and printing stability of the ink composition under different working environment conditions, so that the color of the printed pattern is more uniform;

[0014] On the other hand, during the drying process of the liquid film coated by the ink composition, the alkalinity is reduced due to the volatilization of ammonia and the hydrolysis of silane, and part of the sodium aluminate will be hydrolyzed into aluminum hydroxide, filling the pores between the inorganic pigment particles and the organic resin and the fiber gaps on the surface of the paper substrate, thereby improving the adhesion of the printed pattern;

[0015] Therefore, the ink composition of the present application not only reduces the possibility of ink penetration of thin packaging paper, but also ensures the uniformity and adhesion of printing and reduces the defective rate without using the existing wetting and dispersing agents.

[0016] Optional: The mass ratio of ethanol to water in the regulator is (1.5~4):1.

[0017] By adopting the above technical solution, not only the short-term dispersion effect of the regulator is better, but also the ink viscosity can be adjusted to the appropriate viscosity for printing work - 0.04~0.06 Pa·s by using a smaller amount, thereby reducing the color difference of the ink.

[0018] Optionally, the molar ratio of sodium aluminate to sodium citrate in the auxiliary agent A is 10:2.7.

[0019] By adopting the above technical solution, the adhesion of the printed pattern and the color uniformity at different temperatures are better.

[0020] Optional: also includes 1.4 to 2.8 parts of silane monomer.

[0021] By adopting the above technical scheme, the silane monomer is hydrolyzed in the ink composition to form siloxane, which promotes the fluidity of the ink composition and enhances the effect of the solid matter in the ink composition adaptively flowing in the liquid film due to the liquid surface tension when ethanol evaporates. In addition, cross-linking occurs after the water and ammonia in the ink composition evaporate, thereby enhancing the strength of the cured film of the ink composition, and ultimately enhancing the printing uniformity and adhesion.

[0022] Optionally, the silane monomer is dimethylbis(dimethylamino)silane.

[0023] By adopting the above technical solution, the dispersion is more uniform and the hydrolysis process is more moderate, which is more suitable for the storage and use requirements of the ink composition of the present application.

[0024] The second above-mentioned invention objective of the present invention is achieved through the following technical solutions:

[0025] The method for preparing the ink composition comprises the following steps:

[0026] The color paste, ink resin emulsion, ink defoamer, ammonia water, polyol phosphate, and auxiliary agent A are mixed, and then a regulator is added to mix and adjust the viscosity to obtain an ink composition.

[0027] By adopting the above technical solution, the regulator not only disperses the pigment particles during the window period, but also regulates the viscosity of the ink composition. The regulator is added at the end to facilitate the final regulation of the viscosity of the ink composition.

[0028] In summary, this application has at least the following beneficial effects:

[0029] 1. The ink composition of the present application not only reduces the possibility of ink penetration in thin packaging paper, but also ensures printing uniformity and adhesion, and reduces the defective rate without using existing wetting and dispersing agents;

[0030] 2. The ink composition of the present application improves the adhesion and storage stability of the ink composition by adding an auxiliary agent A compounded with sodium metaaluminate and sodium citrate, a silane monomer, and a polyol phosphate. DETAILED DESCRIPTION

[0031] raw material

[0032] Resin Joncryl143, relative molecular weight less than 200000;

[0033] Defoamer Surfynol104E, relative molecular weight less than 7000;

[0034] Resin Joncryl 624, relative molecular weight 200000~220000;

[0035] Resin Joncryl 8055, relative molecular weight 200000~220000;

[0036] Defoamer Tego foamex 1488, relative molecular weight is 7000~15000;

[0037] The pigment powder is obtained by grinding inorganic mineral pigment powder, and the particle size is 500nm;

[0038] Ammonia water, ethanol, sodium metaaluminate and sodium citrate are commercially available industrial grade products;

[0039] Silane monomers include dimethylbis(dimethylamino)silane and trimethylchlorosilane, which are commercially available industrial grade products;

[0040] Polyol phosphate is a commercially available product of Shandong Wanhua Tianhe New Materials Co., Ltd. with a concentration of 50 wt%.

[0041] Preparation Example 1

[0042] A color paste for ink is prepared from color paste resin, pigment powder, water and color paste auxiliary agent.

[0043] The specific preparation method is as follows:

[0044] The color paste defoamer Tego foamex 810 and the PE wax Jonwax4 are mixed in a mass ratio of 1:4 to obtain a color paste auxiliary agent;

[0045] The color paste resin Joncryl HPD96, pigment powder, water and color paste additive were mixed evenly in a mass ratio of 32:37:25.5:4, and then put into a sand mill to grind and disperse evenly to obtain a color paste.

[0046] Example 1

[0047] An ink composition is prepared using color paste, ink resin emulsion, ink defoamer, ammonia water and a regulator as raw materials.

[0048] The specific preparation method is as follows:

[0049] Weigh 20kg color paste, 80kg ink resin emulsion, 0.2kg ink defoamer, 0.5kg ammonia water, and 5kg regulator;

[0050] Mix the color paste, ink resin emulsion, ink defoamer and ammonia water to obtain material A;

[0051] Then, a regulator is added to material A while stirring. After the regulator is added, the mixture is stirred evenly to obtain an ink composition.

[0052] The ink resin emulsion is obtained by mixing the resin Joncryl 624 and the resin Joncryl 8055 in a mass ratio of 5:3.

[0053] The color paste used was prepared in Preparation Example 1.

[0054] The ink defoamer is Tego foamex 1488.

[0055] The concentration of ammonia water is 26.2wt%.

[0056] The regulator ethanol is mixed with water in a mass ratio of 4:1.

[0057] Comparative Example 1

[0058] An ink composition, which is different from Example 1 in that the ink resin emulsion is Joncryl 143, the ink defoamer is Surfynol 104E, and the regulator is water.

[0059] Comparative Example 2

[0060] An ink composition, which differs from Example 1 in that the regulator is water.

[0061] Comparative Example 3

[0062] An ink composition, which is different from Example 1 in that the ink defoamer is Surfynol 104E.

[0063] Comparative Example 4

[0064] An ink composition, which differs from Example 1 in that the ink resin emulsion is Joncryl 143.

[0065] Comparative Example 5

[0066] An ink composition is prepared using color paste, ink resin emulsion, ink defoamer, ammonia water, a regulator and a wetting dispersant as raw materials.

[0067] Weigh 20kg color paste, 80kg ink resin emulsion, 0.2kg ink defoamer, 0.5kg ammonia water, 5kg regulator, and 1.5kg wetting dispersant;

[0068] First, the color paste, ink resin emulsion, ink defoamer, ammonia water and wetting dispersant are mixed evenly to obtain material A;

[0069] Then, a regulator is added to material A while stirring. After the regulator is added, the mixture is stirred evenly to obtain an ink composition.

[0070] The color paste used was prepared in Preparation Example 1.

[0071] The ink resin emulsion is Joncryl143.

[0072] The ink defoamer is Surfynol 104E.

[0073] The concentration of ammonia water is 26.2wt%.

[0074] The conditioning agent is water.

[0075] The wetting and dispersing agent is Silok-7111.

[0076] Comparative Example 6

[0077] An ink composition, which is different from Comparative Example 5 in that the amount of the wetting and dispersing agent used is 0.8 kg.

[0078] Example 2

[0079] An ink composition, which differs from Example 1 in that a regulator is obtained by mixing ethanol and water in a mass ratio of 1:1.

[0080] Example 3

[0081] An ink composition, which differs from Example 1 in that a regulator is a mixture of ethanol and water in a mass ratio of 1.5:1.

[0082] Example 4

[0083] An ink composition, which differs from Example 1 in that the regulator is a mixture of ethanol and water in a mass ratio of 5:1.

[0084] Example 5

[0085] An ink composition is prepared using color paste, ink resin emulsion, ink defoamer, ammonia water, a regulator and silane monomer as raw materials.

[0086] The specific preparation method is as follows:

[0087] Weigh 20kg color paste, 80kg ink resin emulsion, 0.2kg ink defoamer, 0.5kg ammonia water, 5kg regulator, and 2.5kg silane monomer;

[0088] First, the color paste, ink resin emulsion, ink defoamer, ammonia water and silane monomer are mixed evenly to obtain material A;

[0089] Then, a regulator is added to material A while stirring. After the regulator is added, the mixture is stirred evenly to obtain an ink composition.

[0090] The ink resin emulsion is obtained by mixing the resin Joncryl 624 and the resin Joncryl 8055 in a mass ratio of 5:3.

[0091] The color paste used was prepared in Preparation Example 1.

[0092] The ink defoamer is Tego foamex 1488.

[0093] The concentration of ammonia water is 26.2wt%.

[0094] The regulator ethanol is mixed with water in a mass ratio of 4:1.

[0095] The silane monomer is dimethylbis(dimethylamino)silane.

[0096] Example 6

[0097] An ink composition, which is different from Example 7 in that the silane monomer is trimethylchlorosilane.

[0098] Example 7

[0099] An ink composition is prepared using color paste, ink resin emulsion, ink defoamer, ammonia water, a regulator, silane monomer and polyol phosphate as raw materials.

[0100] The specific preparation method is as follows:

[0101] Weigh 20kg of color paste, 80kg of ink resin emulsion, 0.2kg of ink defoamer, 0.5kg of ammonia water, 5kg of regulator, 2.5kg of silane monomer, and 5.2kg of polyol phosphate;

[0102] First, the color paste, ink resin emulsion, ink defoamer, ammonia water, silane monomer and polyol phosphate are mixed uniformly to obtain material A;

[0103] Then, a regulator is added to material A while stirring. After the regulator is added, the mixture is stirred evenly to obtain an ink composition.

[0104] The ink resin emulsion is obtained by mixing the resin Joncryl 624 and the resin Joncryl 8055 in a mass ratio of 5:3.

[0105] The color paste used was prepared in Preparation Example 1.

[0106] The ink defoamer is Tego foamex 1488.

[0107] The concentration of ammonia water is 26.2wt%.

[0108] The regulator ethanol is mixed with water in a mass ratio of 4:1.

[0109] The silane monomer is dimethylbis(dimethylamino)silane.

[0110] Example 8

[0111] An ink composition is prepared by using color paste, ink resin emulsion, ink defoamer, ammonia water, a regulator, silane monomer, polyol phosphate and auxiliary agent A as raw materials.

[0112] The specific preparation method is as follows:

[0113] Weigh 20 kg of color paste, 80 kg of ink resin emulsion, 0.2 kg of ink defoamer, 0.5 kg of ammonia water, 5 kg of regulator, 2.5 kg of silane monomer, 5.2 kg of polyol phosphate, and 10.6 kg of additive A;

[0114] First, the color paste, ink resin emulsion, ink defoamer, ammonia water, silane monomer, polyol phosphate, and additive A are mixed uniformly to obtain material A;

[0115] Then, a regulator is added to material A while stirring. After the regulator is added, the mixture is stirred evenly to obtain an ink composition.

[0116] The ink resin emulsion is obtained by mixing the resin Joncryl 624 and the resin Joncryl 8055 in a mass ratio of 5:3.

[0117] The color paste used was prepared in Preparation Example 1.

[0118] The ink defoamer is Tego foamex 1488.

[0119] The concentration of ammonia water is 26.2wt%.

[0120] The regulator ethanol is mixed with water in a mass ratio of 4:1.

[0121] The silane monomer is dimethylbis(dimethylamino)silane.

[0122] Additive A is prepared by mixing sodium aluminate and sodium citrate in a mass ratio of 10:2.7.

[0123] Example 9

[0124] An ink composition, which is different from Example 8 in that the auxiliary agent A is a single sodium aluminate.

[0125] Example 10

[0126] An ink composition, which is different from Example 8 in that auxiliary agent A is single sodium citrate.

[0127] Embodiment 11

[0128] An ink composition, which is different from Example 8 in that auxiliary agent A is obtained by compounding sodium metaaluminate and sodium citrate in a mass ratio of 1:1.

[0129] Example 12

[0130] An ink composition, which differs from Example 8 in that auxiliary agent A is a compound of sodium aluminate and sodium citrate in a mass ratio of 1:3.5.

[0131] The ink combinations of Examples 1 to 12 and Comparative Examples 1 to 6 were tested.

[0132] Detection

[0133] Color Transmission Test

[0134] 40cm×20cm, weight 32g / m 2 Use paper as the substrate, print on one side with ink, and check whether there is any transparent pattern formed by ink penetration on the back of the paper after printing.

[0135] Printing uniformity test

[0136] 40cm×20cm, weight 32g / m 2 Use paper as the substrate and print on one side with ink. After printing, check the printed surface of the paper to see if there is any area of ​​printed color difference.

[0137] Adhesion fastness test

[0138] 5cm×5cm, weight 32g / m 2 The paper was used as the substrate and the samples were prepared by printing ink on one side. The test was carried out according to the provisions of GB / T13217.7-2009.

[0139] The test results are shown in the table below.

[0140] Table 1. Test results of Examples 1 to 12 and Comparative Examples 1 to 6

[0141]

[0142] Combining Comparative Example 1 and Comparative Examples 5-6, it can be seen that:

[0143] In Comparative Examples 5 and 6, ink defoamers and ink resin emulsions with relatively small molecular weights were selected and a wetting and dispersing agent was added. In the results of color transmission tests, both Comparative Examples 5 and 6 had the problem of ink penetrating the paper.

[0144] The amount of wetting and dispersing agent used in Comparative Example 5 is more than that in Comparative Example 6. In the printing uniformity test, Comparative Example 5 does not have a printing color difference area, while Comparative Example 6 has a color difference area.

[0145] In addition, comparative example 1 selected ink defoaming agent and ink resin emulsion with relatively small molecular weight but did not add wetting and dispersing agent. In the results of color penetration test, comparative example 1 did not have the problem of ink penetrating paper, and color difference areas appeared in the printing uniformity test.

[0146] It can be seen from this that adding a wetting and dispersing agent to the ink composition can improve the mixing uniformity of the substances in the ink and improve the printing uniformity of the ink, and reduce the possibility of color difference in printing. However, in order to achieve this effect, the proportion of the wetting and dispersing agent added needs to reach a certain amount. At this amount, for thin packaging paper, it will induce the ink to penetrate through the thin packaging paper, resulting in the problem of color pattern on the back.

[0147] By comparing Example 1, Comparative Example 1 and Comparative Example 5, it can be seen that in Example 1 of the present application, an ink defoamer and an ink resin emulsion with a relatively large molecular weight are selected and compounded with ethanol and water as a regulator. In the color penetration test, Example 1 does not have the problem of ink penetrating the paper, and no color difference area appears in the printing uniformity test. Therefore, Example 1 avoids the problem of ink penetration for thin packaging paper without using a wetting dispersant, and also ensures printing quality.

[0148] Combined with Comparative Examples 2 to 4, in Comparative Example 2, an ink defoamer and ink resin emulsion with a relatively large molecular weight were selected and water was used as a single regulator. In the color penetration test, there was no problem of ink penetrating the paper in Comparative Example 2, but a color difference area appeared in the printing uniformity test;

[0149] In Comparative Example 3, an ink defoamer with a relatively small molecular weight and an ink resin emulsion with a relatively large molecular weight were selected, and ethanol and water were compounded as a regulator. In the color penetration test, there was no problem of ink penetrating the paper in Comparative Example 3, but a color difference area appeared in the printing uniformity test;

[0150] In Comparative Example 4, an ink defoamer with a relatively large molecular weight and an ink resin emulsion with a relatively small molecular weight were selected, and ethanol and water were compounded as a regulator. In the color penetration test, there was no problem of ink penetrating the paper in Comparative Example 4, but a color difference area appeared in the printing uniformity test;

[0151] It can be seen from this that implementation 1 of the present application achieves the effect of "avoiding the ink penetration problem for thin packaging paper and ensuring printing quality without using a wetting dispersant". It is achieved by adjusting the dispersed pigment particles with a regulator compounded with ethanol and water, and combining an ink defoamer with a specific molecular weight and an ink resin emulsion.

[0152] Comparing Examples 1 to 4, the mass ratio of ethanol to water in the regulator of Example 2 is 1:1, the mass ratio of ethanol to water in the regulator of Example 3 is 1.5:1, the mass ratio of ethanol to water in Example 1 is 4:1, and the mass ratio of ethanol to water in Example 4 is 5:1. It can be seen from the test results that the color penetration test of Examples 1 to 4 did not show the problem of ink penetrating the color pattern on the back of the paper, and no color difference area appeared in the printing uniformity test. Among them, the adhesion fastness of Example 1, Example 3, and Example 4 is better.

[0153] However, it should be noted that when comparing the samples of printing uniformity during the test, it can be seen that there is no difference in the printed color between Example 1 and Example 3 under naked eye observation, and Examples 2 and 4 both have overall color differences compared with Example 1. Since water and ethanol will eventually evaporate, the color difference is caused by different ratios of the regulator, which makes the ink printing liquid surface tension change differently as the liquid film dries, causing differences in the deposition structure of the pigment particles. Therefore, considering the uniformity and uniformity of color matching, the mass ratio of ethanol and water in the regulator is (1.5~4):1, which is better.

[0154] Comparing Example 1 with Examples 5-6, Examples 5-6 add silane monomers to the ink composition based on Example 1. The silane monomers are hydrolyzed in the ink composition to form siloxanes, which promote the fluidity of the ink composition and enhance the effect of the solid matter in the ink composition adaptively flowing in the liquid film under the liquid surface tension when ethanol evaporates. In addition, cross-linking occurs after the water and ammonia in the ink composition evaporate, which enhances the strength of the cured film of the ink composition, and ultimately enhances the printing uniformity and adhesion. From the test results, it can be seen that the adhesion strength of Examples 5-6 is greater than that of Example 1, and among them, Example 5 is better than Example 6.

[0155] By comparing Example 5 and Example 7, it can be seen that Example 7 adds polyol phosphate to the ink composition based on Example 5, and the polyol phosphate further improves the adhesion of the ink composition. The adhesion fastness of Example 7 is greater than that of Example 5.

[0156] Comparing Example 7 with Examples 8 to 10, Example 8 further adds an auxiliary agent A compared with Example 7, and the auxiliary agent A is obtained by compounding sodium aluminate and sodium citrate; Example 9 adds an amount of sodium aluminate equal to the auxiliary agent A used in Example 8 compared with Example 7; Example 10 adds an amount of sodium citrate equal to the auxiliary agent A used in Example 8 compared with Example 7; in the test results, the adhesion fastness of Example 8 is significantly improved compared with that of Example 7, the adhesion fastness of Example 9 is slightly improved compared with that of Example 7, and the adhesion fastness of Example 10 is not improved compared with that of Example 7. This is because during the drying process of the liquid film coated with the ink composition of the present application, the alkalinity is reduced due to the volatilization of ammonia and the hydrolysis of silane, and part of the sodium aluminate in Example 8 will be hydrolyzed into aluminum hydroxide, filling the pores between the inorganic pigment particles and the organic resin, and filling the fiber gaps on the surface of the paper substrate, thereby improving the adhesion of the printed pattern. At the same time, since the sodium citrate and sodium aluminate in Example 8 form a buffer, they play a role in stabilizing pH fluctuations, thereby avoiding premature hydrolysis of sodium aluminate during storage and stirring before printing, thereby ensuring the role of sodium aluminate. Therefore, the adhesion fastness of Example 8 is significantly improved, while the improvement in Example 9 is weaker.

[0157] Combined with Examples 11-12, the adhesion strength of Examples 11-12 is significantly improved compared with that of Example 7, but lower than that of Example 8. Therefore, the optimal compounding mass ratio of sodium aluminate and sodium citrate in the auxiliary agent A in the present application is 10:2.7.

[0158] The inks obtained in Example 1, Example 5, and Examples 7 to 12 were tested for stability.

[0159] Stability testing

[0160] Take 1 kg of the test ink composition and store it at 60°C for 120 hours and then at 30°C for 18 hours. After unsealing, stir it at 100 r / min for 30 minutes to obtain the test ink. Print the test ink on the sample at room temperature of 30°C to test the color transmittance, printing uniformity and adhesion strength.

[0161] The test results are shown in Table 2.

[0162] Table 2. Stability test results of Example 1, Example 5, and Examples 7 to 10

[0163]

[0164] Combining Tables 1 and 2, it can be seen that after storage in the stability test environment simulation, the adhesion strength of Example 1, Example 5, Example 7, Example 9, and Example 10 all decreased; compared with the printed samples retained in the previous printing uniformity test, Examples 5, Example 7, Example 9, and Example 10 showed color differences with the previous printed samples, while Example 8 did not show a color difference discernible to the naked eye. This is analyzed to be due to the large change in the ink drying speed at different working environment temperatures and the different analysis of the ink combination at different storage temperatures, which correspondingly affects the pH of the ink composition, which may lead to premature cross-linking of the resin in the ink composition, premature cross-linking of the siloxane, and agglomeration of the inorganic pigment particles, which ultimately affects the color.

[0165] However, the adhesion strength of Example 8 did not decrease significantly after storage in the stability test environment simulation, and the storage stability of Example 8 was significantly better than that of Example 1, Example 7, and Examples 9-10.

[0166] In Example 8, sodium aluminate and sodium citrate as a group of buffers can not only stabilize sodium aluminate, but also moderate the storage and printing stability of the ink composition under different working environments and storage temperatures, making the color of the printed pattern more uniform.

[0167] Embodiments 13 to 16

[0168] An ink composition, which differs from Example 8 in that the amounts of raw materials used are different, as follows.

[0169] Table 3. Raw material dosage table of Examples 13 to 16

[0170]

[0171] Embodiments 13 to 16 were tested, and the test results are as follows.

[0172] Table 4. Test results of color penetration test, printing uniformity test and adhesion fastness test of Examples 13 to 16

[0173]

[0174] Table 5. Stability test results of Examples 13 to 16

[0175]

[0176] As can be seen from Tables 2 to 5, Examples 13 to 16 have printing uniformity and adhesion compared to Comparative Example 1, and are ink-proof.

[0177] It can be seen that the mass ratio of the raw materials used in the ink composition of the present application is controlled to be 1 to 40 parts of the color paste.

[0178] When the ink resin emulsion: ink defoaming agent: regulator: ammonia water: silane monomer: polyol phosphate ester: additive A = (60~100): (0.1~1): (3~10): (0.2~0.5): (3~10): (4~5.5): (8.7~11.8), the obtained ink composition has better performance. Even without using a wetting dispersant, it still has excellent printing uniformity and adhesion, and is ink-proof.

[0179] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. After reading this specification, those skilled in the art can make non-creative modifications to this embodiment as needed, but as long as it is within the scope of protection required by the present invention, it will be protected by the patent law.

Claims

1. An ink composition, characterized in that: It comprises the following raw materials in parts by mass: Color paste 1~40 parts, 60~100 parts of ink resin emulsion, 0.1~1 part of ink defoamer, 3~10 parts of regulator, 0.2~0.5 parts of ammonia water, 4-5.5 parts of polyol phosphate, Auxiliary agent A 8.7~11.8 parts; The ink resin emulsion is a polyacrylate emulsion, and the relative molecular weight of the resin is greater than 200,000; The relative molecular weight of the ink defoamer is within 7000-15000. The regulator is a compound of ethanol and water; Additive A is a compound of sodium aluminate and sodium citrate.

2. An ink composition according to claim 1, characterized in that: The mass ratio of ethanol and water in the regulator is (1.5~4):

1.

3. An ink composition according to claim 1, characterized in that: The molar ratio of sodium aluminate to sodium citrate in the auxiliary agent A is 10:2.

7.

4. The ink composition according to claim 1, characterized in that: It also includes 1.4 to 2.8 parts of silane monomer.

5. An ink composition according to claim 4, characterized in that: The silane monomer is dimethylbis(dimethylamino)silane.

6. The method for preparing the ink composition according to any one of claims 1 to 5, characterized in that: The following steps are involved: The color paste, ink resin emulsion, ink defoamer, ammonia water, polyol phosphate, and auxiliary agent A are mixed, and then a regulator is added to mix and adjust the viscosity to obtain an ink composition.

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