An ink cleaning agent, its preparation method and use

Abstract

The application discloses an ink cleaning agent and a preparation method and application thereof. The ink cleaning agent comprises the following components in parts by weight: 10-30 parts of a surfactant; 5-20 parts of an emulsifying dispersant; 1-20 parts of a weak alkaline salt; 1-2 parts of a defoaming agent; 0-10 parts of a complexing agent; and 30-70 parts of water; the surfactant accounts for not less than 10% of the total mass of the ink cleaning agent; the surfactant is ethoxylated alkanol; and the emulsifying dispersant is C8-C18 alcohol ethoxylated and propoxylated. By selecting specific emulsifying dispersants and surfactants, the ink can be effectively removed in cooperation with the weak alkaline salt, the surfactant, the defoaming agent and the complexing agent, and the physical properties of waste plastics are not damaged; and the recycled plastics prepared after the ink on the surface of the waste plastics is cleaned have good mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of printing packaging materials, and more particularly relates to an ink cleaning agent, a preparation method and application thereof. BACKGROUND

[0002] Recycling and utilization of waste plastics is an important path to achieve sustainable development and carbon neutralization goal. Many plastic products in life are often printed on the surface for aesthetic or commercial brand needs. If these printed inks are not removed during recycling and utilization, they will adversely affect the color and performance of plastic products, making them only suitable for low-value applications.

[0003] At present, the commonly used ink in waste plastic resin is water-based polyester ink. The existing technology CN 101787232A uses low-toxicity organic ester to remove ink, which can achieve ink removal, but it will damage the mechanical properties of plastic products, resulting in a decrease in their value. Therefore, there is a need in the art to develop an ink cleaning agent that has good ink removal effect and does not cause degradation of plastic matrix macromolecules. SUMMARY

[0004] The purpose of the present application is to overcome the defects or deficiencies in the prior art that the ink cleaning agent uses volatile and toxic organic solvent compounds or causes degradation of plastic matrix macromolecules, and to provide an ink cleaning agent.

[0005] Another purpose of the present application is to provide a preparation method of the ink cleaning agent.

[0006] Another purpose of the present application is to provide the application of the ink cleaning agent in ink cleaning on the surface of waste plastics.

[0007] To achieve the above purpose, the present application is realized by the following technical solutions:

[0008] An ink cleaning agent, comprising the following components calculated by weight parts:

[0009] The surfactant accounts for not less than 10% of the total mass of the ink cleaning agent; the surfactant is ethoxylated alkanol; the emulsifying dispersant is ethoxylated and propoxylated C8-C18 alcohol.

[0010] In the present application, the weak alkaline salt in the ink cleaning agent can adjust the pH of the cleaning agent system to promote the hydrolysis of the ink decomposition, and will not cause the degradation of the substrate polymer; the surfactant has the effect of promoting the spread and infiltration of the cleaning solution to the material, and the specific surfactant selected has similarity with the plastic surface ink, can loosen the molecular structure of the ink layer, promote the loosening and decomposition of the ink, and the selected ethoxylated C8-C18 alcohol is used as an emulsifying dispersant, which has similar groups with the selected ethoxylated alcohol surfactant, can promote the emulsifying and dispersing effect of the surfactant, make the surfactant form uniform small emulsion droplets in the emulsion system, increase the contact area with the ink to improve the ink removal effect, and improve the efficiency.

[0011] It should be noted that the commonly used ink for waste resin printing is polyurethane ink or polyacrylate ink.

[0012] Further, the ethoxylated alkanol is one or more of ethoxylated tridecanol, ethoxylated pentaerythritol, ethoxylated ethanol, ethoxylated propanol, ethoxylated glycerol or ethoxylated hexanol. Further, the weak alkaline salt is one or more of sodium carbonate, sodium bicarbonate or sodium sulfite.

[0013] Further, the weak alkaline salt is sodium carbonate.

[0014] Further, the defoaming agent is one or more of polydimethylsiloxane, diethylhexanol or distearyl ethylenediamine.

[0015] Further, the defoaming agent is polydimethylsiloxane and / or diethylhexanol.

[0016] Further, the defoaming agent is polydimethylsiloxane.

[0017] In the present application, the commonly used complexing agent can be selected according to the prior art. Further, the complexing agent is one or more of etidronate, phosphine-based polycarboxylic acid, ethylenediaminetetraacetic acid, disodium hypotaurate, citric acid, tartaric acid or gluconic acid. By adding a complexing agent to the ink cleaning agent, the ink removal rate of the ink cleaning agent during repeated use can be effectively improved.

[0018] The present application also protects the preparation method of the above-mentioned ink cleaning agent, which comprises the following steps:

[0019] The water, weak alkaline salt, surfactant, emulsifying dispersant, defoaming agent and complexing agent are mixed uniformly according to the formula proportion to obtain the ink cleaning agent.

[0020] In the present application, the mixing speed can be selected according to the prior art, for example but not limited to, the mixing speed is 50-100 rpm.

[0021] In the present application, the mixing time can be selected according to the prior art, for example, but not limited to, the mixing time is 20-30 min.

[0022] The present application also protects the application of the above-mentioned ink cleaning agent in the ink cleaning of waste plastic surfaces.

[0023] The present application also protects the recycled plastic prepared after cleaning with the above-mentioned ink cleaning agent.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] The present application provides an ink cleaning agent. By selecting specific emulsifying dispersants and surfactants, selecting ethoxylated alkanols as surfactants, and selecting ethoxylated and propoxylated C8-C18 alcohols as emulsifying dispersants, similar groups are selected with the ethoxylated alkanol surfactants, which can promote the emulsifying and dispersing effect of the surfactants, form uniform small emulsion droplets in the emulsion system, increase the contact area with the ink, and improve the ink removal effect; synergistic weak alkaline salt, surfactant, defoaming agent and complexing agent can effectively remove the ink without damaging the physical properties of the waste plastic. After removing the ink, the tensile strength of the waste polycarbonate material is not less than 60 MPa, the notched Izod impact strength is not less than 70 kJ / m 2 ; the ink removal rate is not less than 95%; after removing the ink, the tensile strength of the waste polyethylene material is not less than 20 MPa, the notched Izod impact strength is not less than 60 kJ / m 2 ; the ink removal rate is not less than 95%. The number of repeated uses after adding the complexing agent is not less than 3 times. DETAILED DESCRIPTION

[0026] The present application will be further described in detail below in combination with specific examples, which are only used to explain the present application and not to limit the scope of the present application. The test methods used in the following examples are conventional methods unless otherwise specified; the materials, reagents, etc. used are commercially available reagents and materials unless otherwise specified.

[0027] Waste plastic:

[0028] Waste plastic 1: polycarbonate material printed with ink, waste PC bucket, ink is water-based acrylic ester ink;

[0029] Waste plastic 2: polyethylene material printed with ink, waste LDPE packaging bag, ink is water-based polyurethane ink;

[0030] Surfactant:

[0031] Surfactant 1: Ethoxylated tridecanol, trade name: Tridecanol polyether-4, manufacturer: Hefei Tianjian Chemical Co., Ltd.;

[0032] Surfactant 2: Ethoxylated pentaerythritol, trade name: Modified isomeric alcohol, manufacturer: Hubei Taibang Chemical Co., Ltd.;

[0033] Surfactant 3: Fatty alcohol polyoxyethylene ether AEO-9, trade name: AEO-9, manufacturer: Guangzhou Nalun Chemical Co., Ltd.;

[0034] Surfactant 4: Coconut oil fatty acid diethanolamide, trade name: 6501, manufacturer: Shanghai Yuanye Biological Technology Co., Ltd.;

[0035] Emulsifying dispersant:

[0036] Emulsifying dispersant 1: Ethoxylated and propoxylated C8-C18 alcohol, trade name: Modified polyol, manufacturer: Hubei Lingyan Biological Technology Co., Ltd.;

[0037] Emulsifying dispersant 2: Polyoxyethylene ether, trade name: Drawing agent, manufacturer: Hefei Tianjian Chemical Co., Ltd.;

[0038] Emulsifying dispersant 3: Steareth-21, trade name: Polyoxyethylene stearate, manufacturer: Guangzhou Yuanda New Material Co., Ltd.;

[0039] Defoaming agent:

[0040] Defoaming agent 1: Polydimethylsiloxane, trade name: 201 methyl silicone oil, manufacturer: Hubei Longxin Chemical Industry Co., Ltd.;

[0041] Defoaming agent 2: Diethylhexyl alcohol, trade name: Isopropyl alcohol, manufacturer: Guangzhou Yuanda New Material Co., Ltd.;

[0042] Weak alkaline salt:

[0043] Weak alkaline salt 1: Sodium carbonate;

[0044] Weak alkaline salt 2: Sodium bicarbonate;

[0045] Weak alkaline salt 3: Sodium silicate;

[0046] Complexing agent:

[0047] Complexing agent 1: Etidronate;

[0048] Complexing agent 2: Phosphine-based polycarboxylic acid;

[0049] The weak alkaline salt and the complexing agent are commercially available, and the same raw materials are used in parallel experiments between the examples and the comparative examples.

[0050] The ink cleaning agents in each of the embodiments and comparative examples were prepared according to the formulations in Tables 1-2 by the following method:

[0051] The water, weakly basic salt, surfactant, emulsifying dispersant, defoaming agent, and complexing agent were mixed according to the formulation proportions, and continuously stirred at a speed of 50-100 rpm / min for 20-30 min to obtain a uniformly mixed ink cleaning agent.

[0052] Examples 1-9 and Comparative Examples 1-6

[0053] The amounts of each component of the ink cleaning agent in Examples 1-9 are shown in Table 1.

[0054] Table 1 Amounts of each component of the ink cleaning agent in Examples 1-9 (unit: parts by weight)

[0055]

[0056]

[0057] The amounts of each component of the ink cleaning agent in Comparative Examples 1-6 are shown in Table 2.

[0058] Table 2 Amounts of each component of the ink cleaning agent in Comparative Examples 1-6 (unit: parts by weight)

[0059]

[0060] Comparative Example 7 is a commercially available cleaning agent, and the main components are aromatic hydrocarbons, hydrocarbon solvent oil, and ketone organic matter.

[0061] Performance testing:

[0062] The ink cleaning agents prepared in the examples and comparative examples were tested for performance by the following method:

[0063] (1) Ink removal rate: the ink cleaning agents prepared in Examples 1-9 and Comparative Examples 1-6 and the cleaning agent of commercially available Comparative Example 7 were used to clean waste plastics, and the specific cleaning method was as follows: a certain mass of ink-containing plastic sample was placed in a conical flask, and the same mass of ink cleaning agent prepared in the examples and comparative examples was added, and the mixture was cleaned in a shaking water bath at 60°C for 30 min. The ink removal rate (%) was calculated according to the formula: ink removal rate (%) = (ink area before cleaning - ink area after cleaning) / ink area before cleaning x 100%;

[0064] (2) Mechanical property testing: the material after removal of the ink was tested for tensile properties according to standard ISO 527-2-2012, and impact properties according to standard ISO 180-2000;

[0065] (3) Number of times of reuse: the number of times when the ink removal rate is reduced by 10 percentage points compared to the ink removal rate of the first use.

[0066] The test results of Examples 1-9 and Comparative Examples 1-7 are shown in Tables 3-4.

[0067] Table 3 Test results of ink cleaning agents in Examples 1-9 and Comparative Examples 1-7 after cleaning waste plastic 1

[0068]

[0069] Table 4 Test results of ink cleaning agents in Examples 1-9 and Comparative Examples 1-7 after cleaning waste plastic 2

[0070]

[0071]

[0072] As can be seen from Tables 3 and 4, the ink cleaning agents prepared in the embodiments of the present application have good ink removal and do not damage the mechanical properties of the plastic substrate. Specifically, after the ink is removed from the waste polycarbonate, the tensile strength of the material is not less than 60 MPa, the notched Izod impact strength is not less than 70 kJ / m 2 ; the ink removal rate is not less than 95%; after the ink is removed from the waste polyethylene material, the tensile strength of the material is not less than 20 MPa, the notched Izod impact strength is not less than 60 kJ / m 2 ; the ink removal rate is not less than 95%.

[0073] As can be seen from Examples 1 and 2, when the defoaming agent selected is polydimethylsiloxane, the ink cleaning agent prepared has better comprehensive performance, the mechanical properties of the waste plastic after ink removal are equivalent or better, and the ink removal rate is further improved.

[0074] As can be seen from Examples 1 and 3-4, when the weak alkaline salt selected is sodium carbonate, the ink cleaning agent prepared has better comprehensive performance, the mechanical properties of the waste plastic after ink removal are equivalent or better, and the ink removal rate is further improved.

[0075] As can be seen from Examples 3 and 5-6, when a complexing agent is added to the ink cleaning agent, the number of times of reuse of the cleaning agent is further improved, indicating that the addition of the complexing agent can effectively clean the metal particle impurities in the system and improve the number of times of reuse of the cleaning agent.

[0076] As can be seen from Comparative Examples 1 and 2, when other surfactants are selected, the ink cleaning agent prepared does not damage the mechanical properties of the plastic substrate, but the ink removal effect is significantly reduced, and the ink removal rate is not more than 80%.

[0077] As can be seen from Comparative Example 3 and Comparative Example 4, when other emulsifying dispersants are selected, the prepared ink cleaning agent does not damage the mechanical properties of the plastic substrate, but the ink removal effect is obviously reduced.

[0078] As can be seen from Comparative Example 5, when the amount of weak alkaline salt added is too much, the ink removal rate of the prepared ink cleaning agent is greatly reduced, because the high salt concentration leads to a decrease in the solubility and dispersion of the surfactant in the system, resulting in a decrease in the ink cleaning effect.

[0079] As can be seen from Comparative Example 6, if no defoaming agent is added, even if ethoxylated tridecanol is added as a surfactant and ethoxylated and propoxylated C8-C18 alcohol is added as an emulsifying dispersant, the ink removal rate of the prepared ink cleaning agent is low, because the foaming during the cleaning process leads to a decrease in the effect of the surfactant and the emulsifying dispersant.

[0080] As can be seen from Comparative Example 7, using a commercially available cleaning agent, the ink removal rate can reach more than 90%, but the mechanical properties of the material after ink removal are greatly reduced, the tensile strength of the waste polycarbonate after ink removal is only 50.4 MPa, and the notched Izod impact strength is only 36.5 kJ / m 2 ; the tensile strength of the waste polyethylene resin after ink removal is only 14.7 MPa, and the notched Izod impact strength is only 48.3 kJ / m 2 , which is significantly worse than the materials in the examples, indicating that the basic mechanical properties of the materials are damaged, and it is difficult to realize the high value utilization of the materials.

[0081] In summary, the components and their amounts in the ink cleaning agent in the present application synergize with each other to achieve good ink removal efficiency on the surface of waste plastics, and at the same time, do not damage the plastic substrate and affect its application.

[0082] Obviously, the above examples of the present application are only examples for clearly illustrating the present application, and are not limitations on the embodiments of the present application. For ordinary skilled persons in the art, other different forms of changes or variations can be made on the basis of the above description. Here, it is not necessary and impossible to exhaust all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principles of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. An ink cleaner characterized by comprising: consists of the following components by weight parts: surfactant 10-30 parts; emulsifying dispersant 5-20 parts; weak alkaline salt 1-20 parts; antifoaming agent 1-2 parts; complexing agent 0-10 parts; water 30-70 parts; the surfactant accounts for no less than 10% of the total mass of the ink cleaning agent; the surfactant is ethoxylated alkanol; the emulsifying dispersant is ethoxylated and propoxylated C8-C18 alcohol; the weak alkaline salt is sodium carbonate; the complexing agent is one or several of etidronic acid, phosphinyl polycarboxylic acid, ethylenediaminetetraacetic acid, disodium iminotris (acetic acid), citric acid or gluconic acid.

2. The ink cleaner according to claim 1, wherein The ethoxylated alkanol is one or several of ethoxylated tridecanol, ethoxylated pentaerythritol, ethoxylated ethanol, ethoxylated propanol, ethoxylated glycerol or ethoxylated hexanol.

3. The ink cleaner according to claim 1, wherein The antifoaming agent is one or several of polydimethylsiloxane, diethylhexanol or distearyl ethylenediamine.

4. The ink cleaner according to claim 3, wherein The antifoaming agent is polydimethylsiloxane and / or diethylhexanol.

5. The ink cleaner according to claim 1, wherein The complexing agent is etidronic acid.

6. The method of preparing the ink cleaner according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: The water, weak alkaline salt, surfactant, emulsifying dispersant, antifoaming agent and complexing agent are mixed uniformly according to the formula proportion to obtain the ink cleaning agent.

7. Application of the ink cleaning agent according to any one of claims 1-5 in cleaning the ink on the surface of waste plastic.

8. Recycled plastic, characterized in that, The waste plastic is prepared after being cleaned by the ink cleaning agent according to any one of claims 1-5.

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