A post-stage printing color-changing color paste and its preparation method

Abstract

The present invention provides a color-changing paste for post-stage printing and a preparation method thereof, belonging to the field of pigment chemical industry. The color-changing paste of the present invention comprises the following components in parts by mass: 30-65 parts of a solvent, 20-30 parts of a resin, 5-10 parts of a dispersant, 4-6 parts of a surfactant, and 15-25 parts of a pigment. In the present invention, a modified polyurethane polymer molecule with the latest steric hindrance long-chain structure and anchoring end groups is added as a dispersant, and the anchoring groups contained therein have an anchoring effect on the pigment, so that the pigment is fully dispersed and the storage stability of the paste is increased; the steric hindrance long-chain structure reacts with the resin to form a network structure, improving the gloss and migration resistance of the product.

Description

Technical Field

[0001] The present invention relates to the field of pigment chemical industry, and particularly relates to a color-changing printing paste for post-stage printing and a preparation method thereof. Background Art

[0002] Synthetic leather is a plastic product that simulates the composition and structure of natural leather and can be used as a substitute material. It is usually made with an impregnated non-woven fabric as the mesh layer and a microporous polyurethane layer as the grain surface layer.

[0003] With the improvement of people's living standards and consumption capabilities, and the continuous increase in social demand, the limited natural leather resources are becoming increasingly insufficient; at present, with the rapid development of artificial leather and synthetic leather, they have become the first choice in terms of appearance, function, and perception. Analyzing from the domestic and foreign markets, artificial leather and synthetic leather have largely replaced the natural leather with insufficient resources. Using artificial leather and synthetic leather for the decoration of luggage, clothing, shoes, vehicles, and furniture has been increasingly affirmed by the market. Generally, high-grade artificial leather and synthetic leather will achieve various handfeel and decoration requirements similar to natural leather by increasing the softness, flatness, and gloss of the leather, or by post-treatment to improve the pattern varieties, such as suede leather, napped leather, rubbed leather, embossed leather, etc.

[0004] There are many technical means for the post-treatment of artificial leather and synthetic leather. In addition to high process requirements, the selection of the printing color-changing paste used for the post-treatment of artificial leather and synthetic leather is particularly important. Since the existing printing color-changing paste using water, dichloroethylene acetate, and aldehyde-ketone resins as carriers for color-changing artificial leather and synthetic leather has serious problems such as color migration, poor temperature resistance, back adhesion, and poor compatibility with resins, it brings many troubles to the post-treatment of artificial leather and synthetic leather. To solve such problems, it is urgent to develop a color paste with moderate viscosity, good compatibility with polyurethane resin, acrylic resin, and leather surface treatment agent, good migration resistance, high temperature resistance, and good storage stability. Summary of the Invention

[0005] The purpose of the present invention is to provide a color-changing printing paste for post-stage printing and a preparation method thereof to solve the problems of serious color migration, poor temperature resistance, back adhesion, and poor compatibility with resins existing in the existing synthetic leather and artificial leather dyeing color pastes.

[0006] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] A color-changing printing paste for post-stage printing includes the following components in parts by mass:

[0008] 30 - 65 parts of a solvent, 20 - 30 parts of a resin, 5 - 10 parts of a dispersant, 4 - 6 parts of a surfactant, and 15 - 25 parts of a pigment;

[0009] The dispersant contains a modified polyurethane polymer;

[0010] The resin contains a thermosetting acrylic resin.

[0011] Preferably, the solvent contains a mixture of diacetone alcohol and propylene glycol monomethyl ether acetate; the mass ratio of diacetone alcohol to propylene glycol monomethyl ether acetate is 1 to 1.25:1.

[0012] Preferably, the surfactant contains a propylene glycol block polyether.

[0013] Preferably, the modified polyurethane polymer contains one of AFCONA-4203 and AFCONA-4503.

[0014] Preferably, the pigment contains one of Pigment Yellow 83, Pigment Red 254, Phthalocyanine Blue, and Pigment Violet 23.

[0015] The present invention also provides a method for preparing a color-changing paste for post-stage printing, comprising the following steps:

[0016] 1): Mix the solvent, resin, dispersant, and surfactant to obtain a mixture;

[0017] 2): Mix the mixture obtained in step 1) with the pigment to obtain a material;

[0018] 3): Grind the material obtained in step 2) to obtain a color-changing paste for post-stage printing.

[0019] Preferably, in step 1), the mixing is carried out by stirring the mixed materials at a rotation speed of 800 to 1000 r / min for 8 to 12 min.

[0020] Preferably, in step 2), the mixing is carried out by stirring at a rotation speed of 1000 to 1200 r / min for 25 to 35 min.

[0021] Preferably, in step 3), zirconium beads with a diameter of 0.8 to 1.0 mm are used to grind the material, the grinding temperature is 40 to 50 °C, and the grinding is carried out 2 to 3 times to make the pigment particle size D97 reach below 5 μm.

[0022] The present invention has at least the following beneficial effects:

[0023] 1. By selecting a modified polyurethane polymer as the dispersant, its structure is divided into two parts. One part is an anchoring group, which can anchor the pigment in the color paste, enabling the pigment to be fully dispersed and having good storage stability; the other part is a steric hindrance long-chain structure, which reacts with the thermosetting acrylic resin under heating conditions to form a more stable network structure, which can improve the gloss of the product and make the product have more excellent migration resistance.

[0024] 2. Select a thermosetting acrylic resin as the dispersing resin. The thermosetting acrylic resin is a prepolymer formed by cross-linking reaction with acrylic monomers as the basic components. The molecular weight of the prepolymer is generally small, and the structure contains remaining functional groups. By using the characteristics that the functional groups can further react with each other or with the active functional groups in other system resins (such as polyurethane resin, amino resin, etc.) or the dispersant after heating to cure and form a cross-linked network structure, the encapsulation of organic pigments can be strengthened, so that the color-changing ink for post-stage printing prepared from the ink has excellent gloss and has the properties of solvent resistance, temperature resistance, wear resistance, and scratch resistance.

[0025] 3. Select a propylene glycol block polyether with a main component of polyoxyethylene and polyoxypropylene block polymer as the surfactant to fully wet the pigment, reduce the oil absorption value of the pigment, increase the addition amount of the pigment in the ink system, and reduce the viscosity of the ink.

[0026] 4. Select diacetone alcohol and propylene glycol methyl ether acetate as solvents. They have strong solubility in both polar and non-polar substances, making the ink have excellent compatibility. Specific embodiments

[0027] The present invention provides a color-changing ink for post-stage printing, comprising the following components in parts by mass:

[0028] 30 - 65 parts of solvent, 20 - 30 parts of resin, 5 - 10 parts of dispersant, 4 - 6 parts of surfactant, and 15 - 25 parts of pigment;

[0029] The dispersant contains a modified polyurethane polymer;

[0030] The resin contains a thermosetting acrylic resin.

[0031] In the present invention, the solvent is 30 - 65 parts, preferably 35 - 60 parts, and more preferably 40 - 50 parts; the solvent contains diacetone alcohol (DAA) and propylene glycol methyl ether acetate (PMA), and the mass ratio of diacetone alcohol to propylene glycol methyl ether acetate is preferably 1 - 1.25:1, and more preferably 1.1 - 1.2:1.

[0032] In the present invention, the resin is 20 - 30 parts, preferably 25 - 28 parts; the resin contains a thermosetting acrylic resin, preferably a thermosetting acrylic resin with a glass transition temperature (Tg / ℃) of 33 - 105℃, more preferably a thermosetting acrylic resin with a glass transition temperature of 45 - 70℃, further preferably a thermosetting acrylic resin with a glass transition temperature of 50 - 60℃, and more preferably Keyao Chemical Industry VA - 1036.

[0033] In the present invention, the dispersant is 5 to 10 parts, preferably 7 to 8 parts; the dispersant contains a modified polyurethane polymer; the modified polyurethane polymer contains one of AFCONA-4203 and AFCONA-4503.

[0034] In the present invention, the surfactant is 4 to 6 parts, preferably 5 parts; the surfactant contains propylene glycol block polyether, preferably Haian Petrochemical L62; the main components of the propylene glycol block polyether are polyoxyethylene and polyoxypropylene block polymers; the HLB value (hydrophilic-lipophilic balance value) of the propylene glycol block polyether is 5 to 20, preferably 7 to 15.

[0035] In the present invention, the pigment is 15 to 25 parts, preferably 18 to 23 parts; the pigment contains one of Pigment Yellow 83, Pigment Red 254, Phthalocyanine Blue, and Pigment Violet 23.

[0036] The present invention also provides a method for preparing a color-changing ink for post-stage printing, comprising the following steps:

[0037] 1): Mix the solvent, resin, dispersant, and surfactant to obtain a mixture;

[0038] 2): Mix the mixture obtained in step 1) with the pigment to obtain a material;

[0039] 3): Grind the material obtained in step 2) to obtain a color-changing ink for post-stage printing.

[0040] In the present invention, the rotation speed of the mixing in step 1) is 800 to 1000 r / min, preferably 900 to 950 r / min; the time is 8 to 12 min, preferably 10 to 11 min.

[0041] In the present invention, the rotation speed of the mixing in step 2) is 1000 to 1200 r / min, preferably 1050 to 1100 r / min; the time is 25 to 35 min, preferably 28 to 32 min.

[0042] In the present invention, the grinding in step 3) is to grind the material with zirconium beads of 0.8 to 1.0 mm; the grinding temperature is 40 to 50 °C, preferably 42 to 45 °C; the number of grinding times is 2 to 3 times, preferably 2 times, and the pigment particle size D97 reaches below 5 μm.

[0043] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0044] Example 1

[0045] 1): Add 20 parts of DAA, 20 parts of PMA, 25 parts of thermosetting acrylic resin with a glass transition temperature of 105 °C, 10 parts of modified polyurethane polymer, and 5 parts of propylene glycol block polyether with an HLB value of 15 to a stirring kettle. Stir at a speed of 950 r / min for 11 min to obtain a mixture;

[0046] 2): While stirring, add 23 parts of Pigment Yellow 83 to the mixture obtained in step 1). After the addition, stir at a speed of 1100 r / min for 30 min to obtain a material;

[0047] 3): Add the material obtained in step 2) to a sand mill, use 1.0 mm zirconium beads, control the grinding temperature at 40 °C, and grind twice to obtain a color-changing paste for back-end printing.

[0048] Example 2

[0049] 1): Add 20 parts of DAA, 20 parts of PMA, 25 parts of thermosetting acrylic resin with a glass transition temperature of 56 °C, 10 parts of modified polyurethane polymer, and 5 parts of propylene glycol block polyether with an HLB value of 7 to a stirring kettle. Stir at a speed of 900 r / min for 10 min to obtain a mixture;

[0050] 2): While stirring, add 20 parts of Pigment Yellow 83 to the mixture obtained in step 1). After the addition, stir at a speed of 1100 r / min for 30 min to obtain a material;

[0051] 3): Add the material obtained in step 2) to a sand mill, use 1.0 mm zirconium beads, control the grinding temperature at 40 °C, and grind twice to obtain a color-changing paste for back-end printing.

[0052] Example 3

[0053] 1): Add 20 parts of DAA, 20 parts of PMA, 25 parts of thermosetting acrylic resin with a glass transition temperature of 33 °C, 10 parts of modified polyurethane polymer, and 5 parts of propylene glycol block polyether with an HLB value of 7 to a stirring kettle. Stir at a speed of 900 r / min for 10 min to obtain a mixture;

[0054] 2): While stirring, add 20 parts of Phthalocyanine Blue to the mixture obtained in step 1). After the addition, stir at a speed of 1100 r / min for 30 min to obtain a material;

[0055] 3): Add the material obtained in step 2) to a sand mill, use 1.0 mm zirconium beads, control the grinding temperature at 42 °C, and grind twice to obtain a color-changing paste for back-end printing.

[0056] Comparative Example 1

[0057] A preparation method of a color-changing paste for back-end printing, successively including the following steps:

[0058] 1): Add 25 parts of DAA, 20 parts of PMA, 25 parts of a thermosetting acrylic resin with a glass transition temperature of 105°C, and 10 parts of a modified polyurethane polymer into a stirring kettle, stir at a speed of 900 r / min for 10 min to obtain a mixture;

[0059] 2): While stirring, add 20 parts of Pigment Yellow 83 to the mixture obtained in step 1), and after the addition, stir at a speed of 1100 r / min for 30 min to obtain a material;

[0060] 3): Add the material obtained in step 2) to a sand mill, use 1.0 mm zirconium beads, control the grinding temperature at 40°C, and grind twice to obtain a color-changing paste for back-section printing.

[0061] Comparative Example 2

[0062] 1): Add 25 parts of DAA, 20 parts of PMA, 25 parts of a thermosetting acrylic resin with a glass transition temperature of 56°C, and 10 parts of a modified polyurethane polymer into a stirring kettle, stir at a speed of 900 r / min for 10 min to obtain a mixture;

[0063] 2): While stirring, add 20 parts of Pigment Yellow 83 to the mixture obtained in step 1), and after the addition, stir at a speed of 1100 r / min for 30 min to obtain a material;

[0064] 3): Add the material obtained in step 2) to a sand mill, use 1.0 mm zirconium beads, control the grinding temperature at 40°C, and grind twice to obtain a color-changing paste for back-section printing.

[0065] Comparative Example 3

[0066] 1): Add 25 parts of DAA, 20 parts of PMA, 25 parts of a thermosetting acrylic resin with a glass transition temperature of 33°C, and 10 parts of a modified polyurethane polymer into a stirring kettle, stir at a speed of 900 r / min for 10 min to obtain a mixture;

[0067] 2): While stirring, add 20 parts of Pigment Yellow 83 to the mixture obtained in step 1), and after the addition, stir at a speed of 1100 r / min for 30 min to obtain a material;

[0068] 3): Add the material obtained in step 2) to a sand mill, use 1.0 mm zirconium beads, control the grinding temperature at 42°C, and grind twice to obtain a color-changing paste for back-section printing.

[0069] Example 4

[0070] 1): Add 17 parts of DAA, 13 parts of PMA, 20 parts of a thermosetting acrylic resin with a glass transition temperature of 45°C, 5 parts of a modified polyurethane polymer, and 4 parts of a propylene glycol block polyether with an HLB value of 20 to a stirring kettle. Stir at a speed of 800 r / min for 8 min to obtain a mixture;

[0071] 2): While stirring, add 15 parts of Pigment Red 254 to the mixture obtained in step 1). After adding, stir at a speed of 1050 r / min for 25 min to obtain a material;

[0072] 3): Add the material obtained in step 2) to a sand mill, use 0.8 mm zirconium beads, control the grinding temperature at 50°C, and grind twice to obtain a color paste for printing and color modification in the latter stage.

[0073] Example 5

[0074] 1): Add 35 parts of DAA, 30 parts of PMA, 30 parts of a thermosetting acrylic resin with a glass transition temperature of 65°C, 7 parts of a modified polyurethane polymer, and 6 parts of a propylene glycol block polyether with an HLB value of 5 to a stirring kettle. Stir at a speed of 1000 r / min for 12 min to obtain a mixture;

[0075] 2): While stirring, add 25 parts of Pigment Violet 23 to the mixture obtained in step 1). After adding, stir at a speed of 1200 r / min for 35 min to obtain a material;

[0076] 3): Add the material obtained in step 2) to a sand mill, use 0.9 mm zirconium beads, control the grinding temperature at 45°C, and grind three times to obtain a color paste for printing and color modification in the latter stage.

[0077] The raw material component ratios of Examples 1 - 3 and Comparative Examples 1 - 3 are shown in Table 1:

[0078] Table 1: Raw material component ratios of Examples 1 - 3 and Comparative Examples 1 - 3

[0079]

[0080] For the color pastes for printing and color modification in the latter stage prepared in Examples 1 - 3 and Comparative Examples 1 - 3, use a laser particle size distribution analyzer to measure the pigment particle size D97, and use a rotational viscometer to measure the viscosity at room temperature. The test results are shown in Table 2:

[0081] Table 2: Test results of particle size and viscosity of Examples 1 - 3 and Comparative Examples 1 - 3

[0082]

[0083]

[0084] By comparing the particle size and viscosity through tests, in Comparative Examples 1-3, due to the too large particle size D97 and high viscosity, the product could not meet the required indicators, indicating that the introduction of propylene glycol block polyether can effectively wet the organic pigment, reduce the viscosity of the product, and thus reduce the dispersion difficulty, making the grinding fineness of the product reach the required indicators.

[0085] Furthermore, the post-printing color-changing pastes prepared in Examples 1-5 were mixed with PU resin, PU surface treatment agent, and PVC surface treatment agent, and a 0.6 μm transparent PE film was scraped to observe whether they were compatible, whether there was coarsening and line generation to judge the compatibility.

[0086] The test results are shown in Table 3:

[0087] Table 3: Compatibility test results of Examples 1-5

[0088]

[0089]

[0090] Through the comparison of the compatibility test, Example 1 used propylene glycol block polyether with an HLB value of 15, and Example 4 used propylene glycol block polyether with an HLB value of 20. Therefore, both of them have hydrophilic-lipophobic characteristics, resulting in poor compatibility with the leather surface treatment agent. While Example 2 and 3 used propylene glycol block polyether with an HLB value of 7, and Example 5 used propylene glycol block polyether with an HLB value of 5. Therefore, the above three color pastes have hydrophobic-lipophilic characteristics, and their compatibility is better than that of the color-changing pastes prepared with propylene glycol block polyether with an HLB value of 15 or 20.

[0091] In order to further illustrate the excellent performance of a post-printing color-changing paste, Examples 2 and 3 with good compatibility, as well as traditional reactive weak acid dye water, aldehyde-ketone resin color paste, and binary vinyl chloride acetate resin color paste were used as control examples. After the synthetic leather post-coloring treatment of the leather samples, the leather samples were subjected to temperature resistance test and migration resistance test.

[0092] Temperature resistance test: Place the test leather sample in a forced-air oven at a temperature of 200 ± 2 °C. Take it out and cool it after 90 s, and observe the color change of the leather sample, which is divided into levels 1-5, with level 5 showing no color change at all and level 1 showing severe color change.

[0093] Migration resistance test: Place the test leather sample in a sandwich style between two white sheets, and under the condition of maintaining a constant temperature of 70 °C, apply a load of 100 g / cm 2 , and place it for 12 hours. Judge according to the contamination situation of the white sheet, which is divided into levels 1-5, with level 5 being the best pure white without contamination and level 1 being the worst.

[0094] The test results are shown in Table 4:

[0095] Table 4: Temperature resistance and migration resistance test results of the leather samples treated in Examples 2 and 3 and the control example

[0096]

[0097]

[0098] Through the comparison of temperature resistance and migration resistance tests, leather samples treated with traditional aldehyde-ketone resin color paste, binary vinyl chloride-acetate resin color paste, and reactive weakly acidic dye water in the post-treatment of synthetic leather all showed defects to varying degrees, and the performances of Examples 2 and 3 were excellent.

[0099] The finished leather samples prepared in Examples 2 and 3 were placed in a constant temperature and humidity chamber for regular tracking of the changes in the leather samples. After 120 h, stickiness returned in Example 3, while there was no abnormality in Example 2.

[0100] As can be seen from the above examples, the present invention provides a post-printing color-changing color paste, in which the particle size of the pigment particles reaches D97 ≤ 5 μm, the viscosity is moderate, and it has good compatibility with polyurethane resin, acrylic resin, and leather surface treatment agent. After the post-treatment of synthetic leather on the leather sample, the leather sample has a high temperature resistance grade, a high color migration resistance grade, no stickiness return, and strong practicability.

[0101] The above description is only a preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A back-end printing color-changing color paste, characterized in that, It comprises components in the following parts by mass: 30 - 65 parts of solvent, 20 - 30 parts of resin, 5 - 10 parts of dispersant, 4 - 6 parts of surfactant, 15 - 25 parts of pigment; The dispersant contains a modified polyurethane polymer; The resin contains a thermosetting acrylic resin; The glass transition temperature (Tg / ℃) of the thermosetting acrylic resin is 33 - 105℃; The surfactant is propylene glycol block polyether, and the HLB value of the propylene glycol block polyether is 5 - 7.

2. The post-stage printing color-changing color paste according to claim 1, characterized in that, The solvent contains a mixture of diacetone alcohol and propylene glycol methyl ether acetate; the mass ratio of diacetone alcohol to propylene glycol methyl ether acetate is 1 - 1.25:

1.

3. The post-stage printing color-changing color paste according to claim 1, characterized in that, The modified polyurethane polymer contains one of AFCONA - 4203 and AFCONA - 4503.

4. The post-stage printing color-changing color paste according to claim 1, characterized in that The pigment contains one of Pigment Yellow 83, Pigment Red 254, Phthalocyanine Blue, and Pigment Violet 23.

5. The preparation method of the rear-stage printing color-changing color paste according to any one of claims 1 to 4, characterized in that, It includes the following steps: 1): Mix the solvent, resin, dispersant, and surfactant to obtain a mixture; 2): Mix the mixture obtained in step 1) with the pigment to obtain a material; 3): Grind the material obtained in step 2) to obtain a post - stage printing color - changing color paste.

6. The preparation method of a post-stage printing color-changing color paste according to claim 5, characterized in that, In step 1), the mixing is to stir the mixed materials for 8 - 12 min at a rotation speed of 800 - 1000 r / min.

7. A method for preparing a color-changing paste for post-stage printing according to claim 5 or 6, characterized in that, In step 2), the mixing is to stir for 25 - 35 min at a rotation speed of 1000 - 1200 r / min.

8. A method for preparing a color-changing paste for post-stage printing according to claim 7, characterized in that, In step 3), use zirconium beads with a diameter of 0.8 - 1.0 mm to grind the material, the grinding temperature is 40 - 50℃, and grind 2 - 3 times to make the pigment particle size D97 reach below 5μm.

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