阅读说明：本技术 一种皮革数字印刷用油墨及其制备方法 (Printing ink for leather digital printing and preparation method thereof ) 是由 涂乐平 涂六伟 于 2021-08-30 设计创作，主要内容包括：本申请涉及印刷油墨领域,具体公开了一种皮革数字印刷用油墨及其制备方法,一种皮革数字印刷用油墨,由包含如下重量份数的原料制成：预聚物40-60份、单体55-75份、光引发剂2-8份、色料16-24份、消泡剂1-2份、分散剂1-2份、填料2-12份；所述填料包括玻璃粉1-5份、碳酸钙1-5份、聚乙烯蜡2-6份。其制备方法为按比例将预聚物和光引发剂加入到单体中混合均匀,得到第一混合物；加热第一混合物并持续搅拌,得到第二混合物；将其余原料加入第二混合物中,混合均匀,得到第三混合物；将第三混合物加入研磨机中研磨后,得到皮革数字印刷用油墨。本申请添加的填料硬度较大,可均匀分布在油墨体系中,能进入色料粒子的间隙之间,从而提高了油墨的耐摩擦性。(The application relates to the field of printing ink, and particularly discloses printing ink for leather digital printing and a preparation method thereof, wherein the printing ink for leather digital printing is prepared from the following raw materials in parts by weight: 40-60 parts of prepolymer, 55-75 parts of monomer, 2-8 parts of photoinitiator, 16-24 parts of pigment, 1-2 parts of defoamer, 1-2 parts of dispersant and 2-12 parts of filler; the filler comprises 1-5 parts of glass powder, 1-5 parts of calcium carbonate and 2-6 parts of polyethylene wax. The preparation method comprises the steps of adding the prepolymer and the photoinitiator into the monomer according to the proportion and uniformly mixing to obtain a first mixture; heating the first mixture and continuously stirring to obtain a second mixture; adding the rest raw materials into the second mixture, and uniformly mixing to obtain a third mixture; and adding the third mixture into a grinder to grind to obtain the ink for leather digital printing. The filler added in the ink has higher hardness, can be uniformly distributed in an ink system and can enter gaps among pigment particles, so that the friction resistance of the ink is improved.)

1. The printing ink for the digital printing of the leather is characterized by being prepared from the following raw materials in parts by weight:

40-60 parts of prepolymer, 55-75 parts of monomer, 2-8 parts of photoinitiator, 16-24 parts of pigment, 1-2 parts of defoamer, 1-2 parts of dispersant and 2-12 parts of filler;

the filler comprises 1-5 parts of glass powder, 1-5 parts of calcium carbonate and 2-6 parts of polyethylene wax.

2. The ink for digital printing on leather according to claim 1, wherein: the grain size of the glass powder is 0.7-0.9 μm; the hardness of the glass powder is 7-8;

the particle size of the calcium carbonate is 3-5 μm.

3. The ink for digital printing on leather according to claim 1, wherein: the particle size of the polyethylene wax is 5-10 μm;

the hardness of the polyethylene wax is 3-6;

the density of the polyethylene wax is 0.85-0.95g/cm³。

4. An ink for digital printing on leather according to any one of claims 1 to 3, characterized in that: in the printing ink for the leather digital printing, the addition amount of the filler is 1.5-7%.

5. The ink for digital printing on leather according to claim 1, wherein: the prepolymer includes difunctional urethane acrylate and/or nine-functional urethane acrylate.

6. The ink for digital printing on leather according to claim 5, wherein: the prepolymer comprises bifunctional polyurethane acrylate and nine-functional polyurethane acrylate, wherein the mass ratio of the bifunctional polyurethane acrylate to the nine-functional polyurethane acrylate is 1: (1.3-1.8).

7. The ink for digital printing on leather according to claim 1, wherein: the monomer is one or a mixture of cyclohexanone, propylene glycol monoethyl ether and polyethylene glycol.

8. An ink for digital printing on leather according to any one of claims 6 to 7, characterized in that: the mass ratio of the prepolymer to the monomer is 1: (1.3-1.65).

9. The ink for digital printing on leather according to claim 1, wherein: the pigment is one of iron oxide yellow 313, iron oxide blue TB-01, iron oxide red 190 or carbon black N375;

the photoinitiator is one of 2, 4-dihydroxy benzophenone, 2,4, 6-trimethyl benzoyl phenyl ethyl phosphonate and 2-hydroxy-2-methyl-1-phenyl acetone;

the defoaming agent is one of polydimethylsiloxane, polyoxyethylene and polyoxypropylene;

the dispersing agent is one of naphthalene sulfonic acid formaldehyde condensate, sodium lignosulfonate and vinyl bis stearamide.

10. A method for preparing the ink for leather digital printing according to any one of claims 1 to 9, comprising the steps of:

adding the prepolymer and the photoinitiator into a monomer according to a proportion, and uniformly mixing to obtain a first mixture;

heating the first mixture to 70 ℃, and continuously stirring to obtain a second mixture;

adding the pigment, the defoaming agent, the dispersing agent and the filler into the second mixture, and uniformly mixing to obtain a third mixture;

and adding the third mixture into a grinder to grind to obtain the ink for leather digital printing.

Technical Field

The application relates to the technical field of printing ink, in particular to printing ink for leather digital printing and a preparation method thereof.

Background

The ink is used for important printing materials, and patterns and characters are expressed on a printing stock through printing or inkjet. In recent years, the process of digitally printing leather is widely applied, and the process is that ink is directly printed on the leather according to digital patterns by a jet printing system, and then the ink surface of the leather is placed under an ultraviolet lamp for curing, so that the required printed product can be obtained.

The difference between the polarity of the leather and that of the ink is large, so that the adhesion of the ink on the leather is poor, and the problem of poor friction resistance of an ink printing pattern is caused.

Disclosure of Invention

The application provides an ink for leather digital printing and a preparation method thereof, aiming at improving the rubbing resistance of the ink for leather digital printing.

In a first aspect, the present application provides an ink for digital printing of leather, which adopts the following technical scheme:

the printing ink for the digital printing of the leather is prepared from the following raw materials in parts by weight:

40-60 parts of prepolymer, 55-75 parts of monomer, 2-8 parts of photoinitiator, 16-24 parts of pigment, 1-2 parts of defoamer, 1-2 parts of dispersant and 2-12 parts of filler;

the filler comprises 1-5 parts of glass powder, 1-5 parts of calcium carbonate and 2-6 parts of polyethylene wax.

Because leather and printing ink polarity difference are big, lead to printing ink adhesive force on the leather relatively poor, through adopting above-mentioned technical scheme, this application adds the filler in the printing ink system, and the fineness and the viscosity of filler multiplicable printing ink system to increase the adhesive force of printing ink system, simultaneously, the hardness of filler is great, thereby has strengthened the antifriction of printing ink layer.

Further, in the case of the ink for digital printing on leather having a large pigment content, since the particle diameter of the pigment is small, the viscosity of the ink decreases when the mass ratio of the pigment is large, thereby decreasing the adhesion of the ink and further decreasing the rub resistance of the ink layer.

Specifically, the glass powder, the calcium carbonate and the polyethylene wax particles can enter gaps among pigment particles, the density of an ink system is increased, the compactness of a formed film of the ink is improved, and the glass powder, the calcium carbonate and the polyethylene wax particles are stable in structure and high in hardness, so that the friction resistance of the ink can be effectively improved; meanwhile, after the filler is added into the ink system, the filler has a high covering effect and can prevent oxygen residual free radicals in the air from being contended, so that the number of the residual photocured free radicals is increased, and the curing time of the ink is shortened.

Preferably, the particle size of the glass powder is 0.7-0.9 μm; the hardness of the glass powder is 7-8;

the particle size of the calcium carbonate is 3-5 μm.

By adopting the technical scheme, the glass powder with the particle size of 0.7-0.9 μm can be more uniformly dispersed in an ink system and can better enter gaps among pigment particles, and the glass powder has higher hardness, so that the friction resistance of the ink can be further improved; the calcium carbonate with the grain diameter of 3-5 mu m can more easily enter the gaps among the pigment particles, and the cost of the calcium carbonate is low, so that the cost can be effectively saved.

Preferably, the particle size of the polyethylene wax is 5-10 μm;

the hardness of the polyethylene wax is 3-6;

the density of the polyethylene wax is 0.85-0.95g/cm³。

By adopting the technical scheme, the polyethylene wax with the particle size of 5-10 mu m can more easily enter the gaps among the pigment particles, and the polyethylene wax has higher hardness, so that the friction resistance of the ink can be further improved; the polyethylene wax has low density, is not easy to bond with the prepolymer, and reduces the possibility of blocking an ink jet port of the printing machine.

Preferably, the addition amount of the filler is 1.5 to 7 percent.

By adopting the technical scheme, the time required by ink curing can be effectively reduced and the friction resistance of the ink can be improved by adding the filler, along with the increase of the filler, although the friction resistance of the ink can be increased, the viscosity of the ink can be greatly increased, the curing time can also be increased, the ink jet port of a printing machine can be easily blocked, the proportion of the filler added into an ink system is properly controlled, the ink curing time can be effectively reduced, and the friction resistance of the ink can be improved.

Preferably, the prepolymer comprises difunctional urethane acrylate and/or nine-functional urethane acrylate. Preferably, the prepolymer comprises bifunctional polyurethane acrylate and nine-functional polyurethane acrylate, wherein the mass ratio of the bifunctional polyurethane acrylate to the nine-functional polyurethane acrylate is 1: 1.3-1.8.

By adopting the technical scheme, the bifunctional polyurethane acrylate has low self-crosslinking density, low surface hardness and good flexibility after the ink is cured into a film; the nine-functionality-degree polyurethane acrylate has high self-crosslinking density, can improve the curing speed, surface hardness and adhesive force of the ink after being cured into a film, and enhances the friction resistance of the ink, but has poor flexibility.

By properly controlling the mass ratio of the bifunctional polyurethane acrylate to the nine-functional polyurethane acrylate, the curing speed, the flexibility and the adhesive force of the ink after the ink is cured into a film can be effectively improved, and the friction resistance of the ink is further improved.

Preferably, the monomer is one or a mixture of cyclohexanone, propylene glycol monoethyl ether and polyethylene glycol.

By adopting the technical scheme, the cyclohexanone, the 2-propylene glycol-1-monoethyl ether and the polyethylene glycol are all small molecular compounds and are colorless transparent liquid, the influence on the color of the printing ink is reduced, and the viscosity of a printing ink system can be effectively reduced, wherein the density of the cyclohexanone is 0.953g/cm³The density of 2-propanediol-1-monoethyl ether was 0.897g/cm³The density of the polyethylene glycol is 1.27g/cm³The lower the density, the better the effect of reducing the viscosity of the ink system, and the faster the curing speed of the ink.

Preferably, the mass ratio of the prepolymer to the monomer is 1 to (1.3-1.65).

By adopting the technical scheme, the high prepolymer content can cause the excessive viscosity of the ink system, which is not beneficial to the diffusion of the free radicals of the photoinitiator, and the high power required by the curing of the ink system; with the gradual rise of the content of the monomer, the viscosity of the ink system is reduced, free radicals are easy to diffuse in the ink system, when the amount of the monomer is excessive, the number of the free radicals required by the reaction of the ink system is increased, the power required by the complete curing of the system is increased, and under the condition of certain curing power, the mass ratio of the prepolymer to the monomer is properly controlled, so that the curing time of the ink system can be effectively reduced.

Preferably, the pigment is one of iron oxide yellow 313, iron oxide blue TB-01, iron oxide red 190 or carbon black N375.

The photoinitiator is one of 2, 4-dihydroxy benzophenone, 2,4, 6-trimethyl benzoyl phenyl ethyl phosphonate and 2-hydroxy-2-methyl-1-phenyl acetone;

the defoaming agent is one of polydimethylsiloxane, polyoxyethylene and polyoxypropylene;

the dispersing agent is one of naphthalene sulfonic acid formaldehyde condensate, sodium lignosulfonate and vinyl bis stearamide.

By adopting the technical scheme, when the photoinitiator absorbs the energy of ultraviolet light, free radicals are generated, and the polymerization, crosslinking and curing of monomers can be initiated, so that the curing time of the ink is reduced; the defoaming agent can reduce the surface tension of the printing ink, reduce the formation of foam and improve the adhesive force and the friction resistance of the printing ink after curing; the dispersant reduces the precipitation and agglomeration of the pigment and filler particles, so that the filler is uniformly dispersed in the ink system, and the rubbing resistance of the ink is improved.

In a second aspect, the application provides a method for preparing ink for digital printing of leather, which adopts the following technical scheme:

a preparation method of printing ink for leather digital printing comprises the following steps:

adding the prepolymer and the photoinitiator into a monomer according to a proportion, and uniformly mixing to obtain a first mixture;

heating the first mixture to 70 ℃, and continuously stirring to obtain a second mixture;

adding the pigment, the defoaming agent, the dispersing agent and the filler into the second mixture, and uniformly mixing to obtain a third mixture;

and adding the third mixture into a grinder to grind to obtain the ink for leather digital printing.

By adopting the technical scheme, when the prepolymer and the photoinitiator are added into the monomer, mixed uniformly and heated to 70 ℃, the initiating effect of the photoinitiator is good, and energy is saved; after stirring uniformly, adding the pigment, the defoaming agent, the dispersing agent and the filler, stirring uniformly to uniformly disperse the pigment and the filler in an ink system, reducing the precipitation and agglomeration of the pigment and the filler, reducing the foam of the ink system, increasing the adhesive force and the friction resistance of the ink system, and finally adding the third mixture into a grinding machine for fully grinding until the fineness of the ink is below 5 mu m, so that the dots are clear and the color is true after the ink is printed.

1. Because the filler added in the ink has higher hardness, the filler can be uniformly distributed in an ink system and can enter gaps among pigment particles, so that the friction resistance of the ink is improved;

2. the friction resistance of the ink is further improved by adjusting the proportion of the filler added into the ink system;

3. by properly controlling the mass ratio of the prepolymer to the monomer, the curing time of the ink system is effectively reduced.

Detailed Description

The present application will be described in further detail with reference to examples.

The information on the raw materials to which this application relates is shown in table 1.

Examples

The compounding ratio of each raw material in examples 1 to 5 of the present invention is shown in Table 2.

Table 2 examples 1-5 ink formulations for digital printing of leather

Examples 1 to 5

The components and the corresponding weight of the printing ink for the digital printing of the leather are shown in the table 2, wherein the filler is glass powder A with the grain diameter of 0.7-0.9 mu m, calcium carbonate A with the grain diameter of 3-5 mu m and polyethylene wax A with the grain diameter of 5-10 mu m.

And is prepared by the following method:

adding the prepolymer and the photoinitiator into a monomer according to a proportion, and uniformly mixing to obtain a first mixture;

heating the first mixture to 70 ℃, and continuously stirring to obtain a second mixture;

adding the pigment, the defoaming agent, the dispersing agent and the filler into the second mixture, and uniformly mixing to obtain a third mixture;

and adding the third mixture into a grinder to grind to obtain the ink for leather digital printing.

Example 6

The difference between the ink for leather digital printing and the ink in the example 5 is that the glass powder B with the grain diameter of 1-2 μm is selected as the glass powder.

Example 7

A leather digital printing ink is different from the printing ink of example 5 in that calcium carbonate B with the grain diameter of 7-10 μm is selected as calcium carbonate.

Example 8

The difference between the printing ink for leather digital printing and the printing ink in the example 5 is that the polyethylene wax B with the grain diameter of 10-20 mu m is selected as the polyethylene wax.

Example 9

A digital printing ink for leather is different from that of example 5 in that the mass of glass powder A in the filler is 1g, the mass of calcium carbonate A is 0.5g, and the mass of polyethylene wax A is 0.5 g.

Example 10

A leather digital printing ink was different from example 5 in that the filler contained 4g of glass frit A, 4g of calcium carbonate A and 4g of polyethylene wax A.

Example 11

An ink for digital printing on leather differs from example 5 in that the prepolymer was 44g of difunctional urethane acrylate.

Example 12

An ink for digital printing of leather differs from example 5 in that the prepolymer was 44g of a nine-functional urethane acrylate.

Example 13

An ink for digital printing of leather differs from example 5 in that the prepolymer was 20g of difunctional urethane acrylate and 24g of nine-functional urethane acrylate.

Example 14

An ink for digital printing on leather differs from example 5 in that the prepolymer was 14g of difunctional urethane acrylate and 30g of nine-functional urethane acrylate.

Example 15

An ink for digital printing of leather, differing from example 5 in that the monomer was 55g of cyclohexanone.

Example 16

An ink for digital printing of leather, differing from example 5 in that the monomer was 75g of cyclohexanone.

Comparative example

Comparative example 1

An ink for digital printing of leather, which is different from example 1 in that no filler is added.

Comparative example 2

An ink for digital printing of leather is different from example 1 in that glass frit A is not added to the filler.

Comparative example 3

An ink for digital printing on leather is different from that of example 1 in that calcium carbonate A is not added to the filler.

Comparative example 4

An ink for digital printing on leather is different from that of example 1 in that glass powder A and calcium carbonate A are not added to the filler.

Comparative example 5

An ink for digital printing on leather is different from that of example 1 in that calcium carbonate A and polyethylene wax A are not added to the filler.

Comparative example 6

A leather digital printing ink is different from the printing ink in example 1 in that the mass of glass powder A in a filler is 0.1g, the mass of calcium carbonate A is 0.1g, and the mass of polyethylene wax A is 0.2 g.

Comparative example 7

A leather digital printing ink is different from the printing ink in example 1 in that the mass of glass powder A in a filler is 10g, the mass of calcium carbonate A is 10g, and the mass of polyethylene wax A is 15 g.

Inks for digital printing on leather of comparative examples 1 to 7 were prepared in the same manner as in examples 1 to 16.

Performance test

The following property tests were carried out for the inks provided in examples 1 to 16 and comparative examples 1 to 7 of the present application:

and (3) testing the adhesion performance: the inks prepared in the examples and the comparative examples are respectively taken in equal amount, the inks are added into a digital printer, the same patterns are respectively printed on leather, then the ink side of the leather is placed under an ultraviolet curing machine, the curing time is measured by a stopwatch, and the adhesion fastness of the ink printing side is detected according to GB/T13217.7-2009 'test method for liquid ink adhesion fastness': sticking the adhesive tape on the printing ink surface, rolling the adhesive tape on a tape roller for 3 times, uncovering the adhesive tape after the adhesive tape is placed for 5min, covering the uncovered part with semitransparent millimeter paper with the width of 20mm, counting the number of the grids occupied by the ink layer and the number of the grids occupied by the uncovered ink layer respectively, and calculating according to the following formula:

in the formula:

a-ink adhesion fastness;

A₁-the number of cells of the ink layer;

A₂-the number of cells of the removed ink layer.

And (3) friction resistance: equal amounts of the inks prepared in the examples and the comparative examples were taken, the inks were fed into a digital printer, the same patterns were printed on the leather, respectively, then the ink side of the leather was placed under an ultraviolet curing machine, while the curing time was measured with a stopwatch, and the abrasion resistance grade of the ink printed side was measured according to AATCC 8-2007 standard: a piece of white test dry cotton was covered on the rubbing head, which was then placed on the sample and cranked at a speed of one round trip per second for 10 revolutions to slide the rubbing head back and forth over the sample 20 times (10 times of reciprocal rubbing within 10 s) to assess the degree of color transfer from the sample to the white test cotton, and the dry and wet abrasion was rated on the following scale:

level 5.0 — migration can be ignored or no migration;

4.5 levels-color delivery is the same as 4-5 levels on the natural color scale of the assay soil;

level 4.0-color shift is the same as line 4 on AATCC color transfer scale or level 4 on the dirty color scale;

level 3.5-color shift is the same as line 3.5 on AATCC color transfer scale or level 3 on the soil color scale;

level 3.0 — color transfer is the same as AATCC color transfer scale line 3 or as dirty color scale level 3;

level 2.5-color transfer is the same as line 2 on AATCC color transfer scale or level 2.5 on the dirty color scale;

level 2.0 — color transfer is the same as line 2 on the AATCC color transfer scale or as dirty scale level 2;

level 1.5-color transfer is the same as line 1.5 on AATCC color transfer scale or level 1.5 on soil scale;

level 1.0 — color transfer is the same as line 1 on the AATCC color transfer scale or as level 1 of the dirty scale.

Wherein 10 samples were prepared for each of the examples and comparative examples, 4 of which were tested for adhesion performance and 6 of which were tested for rub resistance, and all of which were tested for cure time, the test data were averaged, and the specific test results are shown in table 3.

Table 3 results of performance testing

As can be seen from the comparison of the data of examples 1 to 5 and comparative examples 1 to 7 in Table 3, the application achieves the purpose of improving the abrasion resistance of the digital printing ink for leather finally through the synergistic cooperation and combined action of a plurality of raw materials.

As can be seen from the comparison of the experimental data of example 1 and comparative examples 1 to 7 in Table 3, the adhesion fastness of the ink and the rub resistance of the ink system can be partially improved by adding only the glass frit to the ink system. According to the ink, a certain amount of filler formed by compounding glass powder, calcium carbonate and polyethylene wax is added into an ink system, the hardness of the glass powder, the calcium carbonate and the polyethylene wax particles is high, and after the glass powder, the calcium carbonate and the polyethylene wax particles enter gaps among pigment particles, the friction resistance of the ink is improved, and the curing time of the ink is shortened.

According to the comparison of the experimental data of the example 1 and the comparative examples 6 to 7 in the table 3, the friction resistance and the curing time of the ink after film forming can be effectively improved by controlling the proportion of the filler added in the ink formula; when the filler added into the ink system is less, the adhesion fastness of the ink after curing is reduced, the curing time is longer, and the friction resistance is weakened; when the filler added into the ink system is excessive, the friction resistance of the ink system is better, but the density of the ink system is too high, the curing time is longer, and the ink jet nozzle of the digital printer is easy to block.

According to the comparison of the experimental data of the example 5 and the examples 6 to 8 in the table 3, the friction resistance of the ink after curing can be effectively improved by controlling the particle sizes of the glass powder, the calcium carbonate and the polyethylene wax in the ink formulation of the present application, and the excessive particle sizes of the glass powder, the calcium carbonate and the polyethylene wax can cause the excessive viscosity of the ink system, so that the pigment and the filler particles are easy to aggregate, the curing time of the ink is prolonged, and the friction resistance of the ink after curing is reduced.

According to the comparison of the experimental data of example 5 and comparative examples 9-10 in table 3, the friction resistance of the ink after film formation can be effectively improved and the curing time can be reduced by controlling the proportion of the filler added in the ink formulation of the present application.

As shown by comparing the experimental data of example 5 and examples 11-14 in Table 3, the mass ratio of the bifunctional urethane acrylate to the nine-functional urethane acrylate in the ink formulation of the present application is within a certain range, so as to improve the rubbing resistance of the cured ink, when the mass of the bifunctional urethane acrylate is increased, the adhesion of the cured ink is slightly low, the rubbing resistance is poor, and when the mass of the nine-functional urethane acrylate is increased, the curing time is reduced, the rubbing resistance is high, but the viscosity of the ink system is high, so that the ink jet head is easily blocked and the ink is not uniformly sprayed.

As can be seen from the comparison of the experimental data of example 5 and examples 15-16 in Table 3, the ink wear resistance is improved and the curing time is reduced when the mass ratio of the monomers to the prepolymer in the ink formulation of the present application is within a certain range.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.