Surface printing process for scratch-resistant corrugated carton

Abstract

The invention relates to the technical field of surface printing, in particular to a scratch-resistant corrugated carton surface printing process. The printing technology comprises the following operation steps that S1, paper separation and line pressing are conducted on a corrugated board according to the required specification, and the corrugated board is sheared according to a pressing line; s2, the surface of the corrugated board to be printed is coated with waterborne polyurethane emulsion and dried, and the pretreated corrugated board is obtained; s3, carrying out digital printing on the surface of the pretreated corrugated board by adopting scratch-resistant digital ink; s4, carrying out hot air drying on the corrugated board subjected to digital printing under ultraviolet radiation; and S5, the corrugated boards treated in the step S4 are subjected to nailing, bonding or adhesive tape attaching bonding forming. According to the surface printing technology for the scratch-resistant corrugated carton, the technology is simple, operation is easy to control, the quality of the manufactured corrugated carton is stable, surface ink of the scratch-resistant corrugated carton has the advantages of abrasion resistance and solvent resistance, and meanwhile waterborne polyurethane is high in bonding strength and stable in connection.

Description

Technical Field

[0001] The present invention relates to the technical field of surface printing, and particularly relates to a surface printing process for scratch-resistant corrugated cartons. Background Art

[0002] The essence of traditional printing is a large-scale replication process, which can only be achieved through printing plates. However, with the development of the times and the continuous update of technologies in different fields, customers have higher and higher requirements for printing materials, especially for the increasing demand for personalized orders and small batches in corrugated carton packaging printing.

[0003] Digital printing is different from the cumbersome process of traditional printing. The biggest features in the printing production process are no plate and variable information, covering multiple technical fields such as printing, electronics, computer, network, and communication. Digital printing uses electronic documents as carriers and transmits them to digital printing equipment through network transmission to achieve direct printing, which is suitable for the corrugated packaging printing field to accept small batch orders or personalized orders. However, due to technical reasons, most digital inks on the market currently have problems in terms of friability, adhesiveness, solvent resistance, and curability. Especially for the corrugated cartons often used for packaging goods, the bonding strength of low- and mid-range digital ink printing is average, and the printed layer is very easy to fall off due to friction, affecting the aesthetic effect of corrugated packaging printing, which causes inconvenience to users and cannot meet the usage needs of consumers. Summary of the Invention

[0004] In order to overcome the disadvantages and deficiencies existing in the prior art, the purpose of the present invention is to provide a surface printing process for scratch-resistant corrugated cartons. The process is simple, easy to control in operation, conducive to large-scale industrial production, the quality of the obtained corrugated cartons is stable, the surface ink of the scratch-resistant corrugated cartons has the characteristics of wear resistance and solvent resistance, and at the same time, the waterborne polyurethane has strong bonding strength, firm connection, and excellent comprehensive performance.

[0005] The purpose of the present invention is achieved through the following technical solutions: A surface printing process for scratch-resistant corrugated cartons, the printing process includes the following operation steps:

[0006] S1: Cut the corrugated board according to the required specifications and score it, and shear the corrugated board according to the score line;

[0007] S2: Coat the surface of the corrugated board to be printed with a waterborne polyurethane emulsion and dry it to obtain a pre-treated corrugated board;

[0008] S3: Conduct digital printing on the surface of the pre-treated corrugated board with scratch-resistant digital ink;

[0009] S4: Hot air dry the digitally printed corrugated board under ultraviolet irradiation;

[0010] S5: The corrugated cardboard processed in step S4 is formed by nailing, bonding or taping.

[0011] In the above technical solution, in step S2, the coating amount of the aqueous polyurethane emulsion is 30 - 40 / m 2 ; in step S3, the coating amount of the rub-resistant digital ink is 45 - 55 g / m 2 .

[0012] In the above technical solution, in step S2, the drying temperature of the aqueous polyurethane emulsion is 90 - 110 °C, and the drying time is 2 - 3 min.

[0013] In the above technical solution, in step S4, the ultraviolet lamp irradiation time is 3 - 6 min, the power of the ultraviolet lamp is controlled at 500 - 800 W, the distance between the corrugated cardboard and the ultraviolet lamp is 7 - 15 cm, and the hot air temperature is 50 - 80 °C.

[0014] The surface printing process of the rub-resistant corrugated carton of the present invention is simple, easy to control, conducive to large-scale industrial production, the quality of the obtained corrugated carton is stable, the ink on the surface of the rub-resistant corrugated carton has the characteristics of wear resistance and solvent resistance, and at the same time, the aqueous polyurethane has strong bonding strength, stable connection and excellent comprehensive performance.

[0015] In the above technical solution, the rub-resistant digital ink comprises the following raw materials in parts by weight: 12 - 20 parts of pigment, 4 - 6 parts of styrene-acrylic emulsion, 8 - 12 parts of acrylic modified alkyd resin, 5 - 7 parts of hydroxyl-terminated nitrile rubber, 5 - 6 parts of barium sulfonate, 7 - 9 parts of alkyd aryl sulfonate, 1 - 3 parts of photoinitiator and 30 - 55 parts of organic solvent.

[0016] In the above technical solution, the photoinitiator is photoinitiator 1173.

[0017] In the above technical solution, the pigment comprises at least one of yellow 185, blue 15, red 146, carbon black or titanium dioxide.

[0018] In the above technical solution, the organic solvent is composed of C12 - 20 isoparaffin and white mineral oil mixed in a mass ratio of 17 - 19:1 - 2.

[0019] In the above technical solution, the barium sulfonate is barium sulfonate of type T701, and the alkyd aryl sulfonate is isopropylamine salt of dodecylbenzenesulfonic acid with CAS number 26264 - 05 - 1.

[0020] In the above technical solution, the preparation method of the rub-resistant digital ink comprises the following steps:

[0021] A1: At room temperature, mix barium sulfonate, alkyd aryl sulfonate and organic solvent evenly to obtain mixture A;

[0022] A2: Under the condition of avoiding light, add pigments, photoinitiators, styrene-acrylic emulsion, acrylic modified alkyd resin and hydroxyl-terminated nitrile rubber into mixture A and stir for 1 - 3 h to obtain the rub-resistant digital ink.

[0023] In the above technical solution, the aqueous polyurethane emulsion comprises the following raw materials in parts by weight: isophorone diisocyanate 75 - 85 parts, polyethylene glycol 18 - 22 parts, carboxymethyl cellulose 10 - 12 parts, epoxy resin 7 - 8 parts, catalyst 0.2 - 0.4 part, chain extender 4.5 - 5.5 parts, deionized water 10 - 12 parts.

[0024] In the above technical solution, the catalyst is at least one of dibutyltin dilaurate and stannous octoate.

[0025] In the above technical solution, the chain extender is dimethylolpropionic acid.

[0026] In the above technical solution, the preparation method of the aqueous polyurethane emulsion comprises the following steps:

[0027] B1: Add polyethylene glycol and catalyst into a reaction kettle, heat up to 130 - 150 °C, evacuate to remove water for 2 - 2.5 h, cool down to 90 - 110 °C, add isophorone diisocyanate, and react for 2.5 - 3.5 h to obtain product A;

[0028] B2: Add carboxymethyl cellulose, epoxy resin and chain extender into product A, and continue to react at 75 - 85 °C for 2 - 3 h to obtain product B;

[0029] B3: Lower the temperature of the system to room temperature, add ethylenediamine for neutralization, then slowly add deionized water to product B and stir evenly to obtain the aqueous polyurethane emulsion.

[0030] The beneficial effects of the present invention are as follows: The rub-resistant corrugated cardboard surface printing process of the present invention has a simple process and easy operation control, which is conducive to large-scale industrial production. The quality of the corrugated cardboard obtained is stable. The ink on the surface of the rub-resistant corrugated cardboard has the characteristics of wear resistance and solvent resistance. At the same time, the aqueous polyurethane has strong bonding strength and stable connection, and the comprehensive performance is excellent. Specific Embodiments

[0031] For the convenience of those skilled in the art to understand, the present invention will be further described below in conjunction with embodiments. The content mentioned in the embodiments does not limit the present invention.

[0032] Example 1

[0033] In this embodiment, a rub-resistant corrugated cardboard surface printing process, the printing process comprises the following operating steps:

[0034] S1: Score and crease the corrugated board according to the required specifications, and cut the corrugated board according to the crease.

[0035] S2: Coat the surface of the corrugated board to be printed with aqueous polyurethane emulsion and dry it to obtain the pre-treated corrugated board.

[0036] S3: Perform digital printing on the surface of the pre-treated corrugated board using rub-resistant digital ink.

[0037] S4: Hot air dry the digitally printed corrugated board under ultraviolet irradiation.

[0038] S5: Glue and form the corrugated board processed in step S4 by nailing, bonding or taping.

[0039] Further, in step S2, the coating amount of the aqueous polyurethane emulsion is 35 / m 2 ; in step S3, the coating amount of the rub-resistant digital ink is 50 g / m 2 .

[0040] Further, in step S2, the drying temperature of the aqueous polyurethane emulsion is 95°C and the drying time is 2.5 min; in step S4, the ultraviolet lamp irradiation time is 4 min, the power of the ultraviolet lamp is controlled at 700 W, the distance between the corrugated board and the ultraviolet lamp is 8 cm, and the hot air temperature is 70°C.

[0041] Further, the rub-resistant digital ink comprises the following raw materials in parts by weight: 12 parts of pigment, 4 parts of styrene-acrylic emulsion, 8 parts of acrylic modified alkyd resin, 5 parts of hydroxyl-terminated nitrile rubber, 5 parts of barium sulfonate, 7 parts of alkyd aryl sulfonate, 1 part of photoinitiator and 30 parts of organic solvent.

[0042] In this embodiment, the acrylic modified alkyd resin is selected from 996-60 or 968-60 of Tianjin TEDA Guolong Chemical Co., Ltd.; the hydroxyl-terminated nitrile rubber is selected from TL910 of Tangyi Chemical Industry; the styrene-acrylic emulsion is selected from 7199 of Henkel of Germany; the barium sulfonate uses barium sulfonate of model T701, and the alkyd aryl sulfonate uses isopropylamine salt of dodecylbenzenesulfonic acid with CAS number 26264-05-1.

[0043] Further, the photoinitiator is photoinitiator 1173.

[0044] Further, the organic solvent is composed of C12-20 isoparaffin and white mineral oil mixed in a mass ratio of 18:2.

[0045] Further, the pigment is Yellow 185.

[0046] Further, the preparation method of the rub-resistant digital ink includes the following steps:

[0047] A1: Mix barium sulfonate, alkyd aryl sulfonate and organic solvent evenly to obtain mixture A;

[0048] A2: Under the condition of avoiding light, add pigment, photoinitiator, styrene-acrylic emulsion, acrylic modified alkyd resin and hydroxyl-terminated nitrile rubber into mixture A and stir for 2 h to obtain rub-resistant digital ink.

[0049] Further, the aqueous polyurethane emulsion includes the following raw materials in parts by weight: 75 parts of isophorone diisocyanate, 18 parts of polyethylene glycol, 10 parts of carboxymethyl cellulose, 7 parts of epoxy resin, 0.2 part of catalyst, 4.5 parts of chain extender, and 10 parts of deionized water.

[0050] In this embodiment, the polyethylene glycol is selected from polyethylene glycol 1000; the epoxy resin is bisphenol A type epoxy resin with an epoxy value of 0.46 from Shanghai Complex High-Tech Materials Co., Ltd.; the carboxymethyl cellulose is carboxymethyl cellulose with a CAS number of 9000-11-7.

[0051] Further, the chain extender is dimethylolpropionic acid.

[0052] Further, the catalyst is dibutyltin dilaurate.

[0053] Further, the preparation method of the aqueous polyurethane emulsion includes the following steps:

[0054] B1: Add polyethylene glycol and catalyst into the reaction kettle, heat up to 140 °C, evacuate to remove water for 2.2 h, cool down to 100 °C, add isophorone diisocyanate, and react for 3 h to obtain product A;

[0055] B2: Add carboxymethyl cellulose, epoxy resin and chain extender into product A, and continue to react at 80 °C for 2.5 h to obtain product B;

[0056] B3: Cool the system temperature to room temperature, add ethylenediamine for neutralization, and then slowly add deionized water into product B and stir evenly to obtain the aqueous polyurethane emulsion.

[0057] Example 2

[0058] In this example, the rub-resistant digital ink includes the following raw materials in parts by weight: 16 parts of pigment, 5 parts of styrene-acrylic emulsion, 10 parts of acrylic modified alkyd resin, 6 parts of hydroxyl-terminated nitrile rubber, 5 parts of barium sulfonate, 8 parts of alkyd aryl sulfonate, 2 parts of photoinitiator, and 40 parts of organic solvent.

[0059] Further, the preparation method of the rub-resistant digital ink includes the following steps:

[0060] A1: Mix barium sulfonate, alkyd aryl sulfonate and organic solvent evenly to obtain mixture A;

[0061] A2: Under the condition of avoiding light, add pigment, photoinitiator, styrene-acrylic emulsion, acrylic modified alkyd resin and hydroxyl-terminated nitrile rubber into mixture A and stir for 2 h to obtain the rub-resistant digital ink.

[0062] Further, the aqueous polyurethane emulsion comprises the following raw materials in parts by weight: 80 parts of isophorone diisocyanate, 20 parts of polyethylene glycol, 11 parts of carboxymethyl cellulose, 7 parts of epoxy resin, 0.3 part of catalyst, 5 parts of chain extender, and 11 parts of deionized water.

[0063] Further, the preparation method of the aqueous polyurethane emulsion comprises the following steps:

[0064] B1: Add polyethylene glycol and catalyst into a reaction kettle, heat up to 140 °C, evacuate to remove water for 2.2 h, cool down to 100 °C, add isophorone diisocyanate, and react for 3 h to obtain product A;

[0065] B2: Add carboxymethyl cellulose, epoxy resin and chain extender into product A, and continue to react at 80 °C for 2.5 h to obtain product B;

[0066] B3: Cool the temperature of the system to room temperature, add ethylenediamine for neutralization, then slowly add deionized water to product B and stir evenly to obtain the aqueous polyurethane emulsion.

[0067] The remaining content of this example is the same as that of Example 1.

[0068] Example 3

[0069] In this example, the rub-resistant digital ink comprises the following raw materials in parts by weight: 20 parts of pigment, 6 parts of styrene-acrylic emulsion, 12 parts of acrylic modified alkyd resin, 7 parts of hydroxyl-terminated nitrile rubber, 6 parts of barium sulfonate, 9 parts of alkyd aryl sulfonate, 3 parts of photoinitiator, and 55 parts of organic solvent.

[0070] Further, the preparation method of the rub-resistant digital ink comprises the following steps:

[0071] A1: Mix barium sulfonate, alkyd aryl sulfonate and organic solvent evenly to obtain mixture A;

[0072] A2: Under the condition of avoiding light, add pigment, photoinitiator, styrene-acrylic emulsion, acrylic modified alkyd resin and hydroxyl-terminated nitrile rubber into mixture A and stir for 2.5 h to obtain the rub-resistant digital ink.

[0073] Further, the aqueous polyurethane emulsion comprises the following raw materials in parts by weight: 85 parts of isophorone diisocyanate, 22 parts of polyethylene glycol, 12 parts of carboxymethyl cellulose, 8 parts of epoxy resin, 0.4 part of catalyst, 5.5 parts of chain extender, and 12 parts of deionized water.

[0074] Further, the preparation method of the aqueous polyurethane emulsion comprises the following steps:

[0075] B1: Add polyethylene glycol and catalyst into a reaction kettle, heat up to 145 °C, evacuate to remove water for 2.2 h, cool down to 100 °C, add isophorone diisocyanate, and react for 3 h to obtain product A;

[0076] B2: Add carboxymethyl cellulose, epoxy resin, and chain extender into product A, and continue to react at 85 °C for 2.5 h to obtain product B;

[0077] B3: Cool the system temperature to room temperature, add ethylenediamine for neutralization, and then slowly add deionized water to product B and stir evenly to obtain the aqueous polyurethane emulsion.

[0078] Comparative Example 1

[0079] The difference between this comparative example and Example 1 is that an equal amount of polyethylene glycol is used to replace carboxymethyl cellulose and epoxy resin.

[0080] Further, the aqueous polyurethane emulsion comprises the following raw materials in parts by weight: 75 parts of isophorone diisocyanate, 35 parts of polyethylene glycol, 0.2 part of catalyst, 4.5 parts of chain extender, and 10 parts of deionized water.

[0081] That is, in this comparative example, the preparation method of the aqueous polyurethane emulsion comprises the following steps:

[0082] B1: Add polyethylene glycol and catalyst into a reaction kettle, heat up to 140 °C, evacuate to remove water for 2.2 h, cool down to 100 °C, add isophorone diisocyanate, and react for 3 h to obtain product A;

[0083] B2: Add chain extender into product A, and continue to react at 80 °C for 2.5 h to obtain product B;

[0084] B3: Cool the system temperature to room temperature, add ethylenediamine for neutralization, and then slowly add deionized water to product B and stir evenly to obtain the aqueous polyurethane emulsion.

[0085] Comparative Example 2

[0086] The difference between this comparative example and Example 1 is that the rub-resistant digital ink uses the UV digital spraying ink of the DSKUV02-501 model on the market, namely Deskun.

[0087] Performance Detection Test

[0088] Performance tests were carried out on the rub-resistant corrugated cartons prepared in Examples 1-3 and Comparative Examples 1-2. The abrasion resistance and solvent resistance of the rub-resistant digital ink on the surface of the rub-resistant corrugated cartons were tested, and the bonding performance of the aqueous polyurethane emulsion was also tested. The test data are shown in Table 1 below:

[0089] Table 1

[0090]

[0091] The bonding strength test was carried out by the 3M tape test method: Place the intermediate product horizontally, completely bond the 3M600 tape to the rub-resistant digital ink on the surface of the rub-resistant corrugated carton without air bubbles, let it stand for 20 s, pull the tape vertically at 90 degrees, and tear off the tape within 1 s. Check whether the tape adheres to the paint of the rub-resistant digital ink, and test multiple times at the same position;

[0092] Abrasion resistance test: Cut the prepared rub-resistant corrugated board into the shape specified in GB / T 1768-2006, place it on a TABER abrasion tester (GT-7012-T) to observe the surface change of the rub-resistant digital ink on the surface. The type of grinding wheel is CS-10, the set rotation speed is 42 r / min, and the surface load weight is 500 g. The "showing the bottom" in Table 1 means showing the bottom surface, that is, the rub-resistant digital ink is worn, and the film layer formed by the coating of the aqueous polyurethane emulsion can be seen.

[0093] Solvent resistance test: After applying toluene on the surface of the rub-resistant corrugated carton for 30 min, observe whether the paint of the rub-resistant digital ink detaches into the toluene or swells. Detachment is unqualified, obvious swelling but no detachment is good, and no obvious swelling or slight swelling is excellent.

[0094] The above embodiments are the preferred implementation solutions of the present invention. In addition, the present invention can also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A surface printing process for scratch-resistant corrugated cartons, characterized in that: The printing process includes the following operating steps: S1: Cut the corrugated board according to the required specifications and score it, and shear the corrugated board according to the score line; S2: Coat the surface of the corrugated board to be printed with an aqueous polyurethane emulsion and dry it to obtain a pre-treated corrugated board; S3: Perform digital printing on the surface of the pre-treated corrugated board with scratch-resistant digital ink; S4: Hot air dry the digitally printed corrugated board under ultraviolet irradiation; S5: Bond and form the corrugated board treated in step S4 by nailing, gluing or taping.

2. A surface printing process for a rub-resistant corrugated cardboard box according to claim 1, characterized in that: In step S2, the coating amount of the aqueous polyurethane emulsion is 30 - 40 / m 2 ; in step S3, the coating amount of the rub-resistant digital ink is 45 - 55 g / m 2 .

3. A surface printing process for a scratch-resistant corrugated cardboard box according to claim 1, characterized in that: In step S2, the drying temperature of the aqueous polyurethane emulsion is 90 - 110 °C, and the drying time is 2 - 3 min.

4. A surface printing process for a scratch-resistant corrugated cardboard box according to claim 1, characterized in that: In step S4, the ultraviolet lamp irradiation time is 3 - 6 min, the power of the ultraviolet lamp is controlled at 500 - 800 W, the distance between the corrugated board and the ultraviolet lamp is 7 - 15 cm, and the hot air temperature is 50 - 80 °C.

5. A surface printing process for a scratch-resistant corrugated cardboard box according to claim 1, characterized in that: The scratch-resistant digital ink includes the following raw materials in parts by weight: 12 - 20 parts of pigment, 4 - 6 parts of styrene-acrylic emulsion, 8 - 12 parts of acrylic modified alkyd resin, 5 - 7 parts of hydroxyl-terminated nitrile rubber, 5 - 6 parts of barium sulfonate, 7 - 9 parts of alkyd aryl sulfonate, 1 - 3 parts of photoinitiator, and 30 - 55 parts of organic solvent.

6. A surface printing process for a scratch-resistant corrugated cardboard box according to claim 5, characterized in that: The organic solvent is composed of C12 - 20 isoparaffin and white mineral oil mixed in a mass ratio of 17 - 19:1 - 2.

7. A surface printing process for a rub-resistant corrugated cardboard box according to claim 5, characterized in that: The preparation method of the scratch-resistant digital ink includes the following steps: A1: Mix barium sulfonate, alkyd aryl sulfonate and organic solvent evenly to obtain mixture A; A2: Under light-shielded conditions, add pigment, photoinitiator, styrene-acrylic emulsion, acrylic modified alkyd resin and hydroxyl-terminated nitrile rubber to mixture A and stir for 1 - 3 h to obtain scratch-resistant digital ink.

8. A surface printing process for a scratch-resistant corrugated cardboard box according to claim 1, characterized in that: The aqueous polyurethane emulsion includes the following raw materials in parts by weight: 75 - 85 parts of isophorone diisocyanate, 18 - 22 parts of polyethylene glycol, 10 - 12 parts of carboxymethyl cellulose, 7 - 8 parts of epoxy resin, 0.2 - 0.4 parts of catalyst, 4.5 - 5.5 parts of chain extender, and 10 - 12 parts of deionized water.

9. A surface printing process for a scuff-resistant corrugated cardboard box according to claim 7, characterized in that: The chain extender is dimethylolpropionic acid.

10. A surface printing process for a scratch-resistant corrugated cardboard box according to claim 7, characterized in that: The catalyst is at least one of dibutyltin dilaurate and stannous octoate.

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