A deinking agent and deinking process for thermal transfer waste paper

Abstract

The application discloses a deinking agent and a deinking process for heat transfer printing waste paper. The deinking agent for heat transfer printing waste paper comprises a solubilizing agent, a surfactant and a penetrating agent; the solubilizing agent is selected from polyesters; the polyester contains an ethylene glycol phthalic acid polycondensation structure; the surfactant comprises at least one of triphenyl ethane phenol polyoxyethylene, triphenyl ethane phenol polyoxyethylene sodium sulfate, glycerol ether oleic acid ester or oleic acid polyoxyethylene ester; and the penetrating agent comprises at least one of ethylene glycol butyl ether, diethylene glycol butyl ether or ethylene glycol phenyl ether. Through the synergistic effect of the specific solubilizing agent, the surfactant and the penetrating agent, the obtained deinking agent has good affinity to disperse dyes and hydrophobic impurities, can effectively perform capacity expansion, emulsification and penetration on the inks such as disperse dyes and hydrophobic impurities remaining on the heat transfer printing waste paper, so that the effective removal of the inks remaining on the heat transfer printing waste paper is realized, and the whiteness of the recycled paper is improved.

Description

Technical Field

[0001] This invention belongs to the field of waste paper deinking technology, and particularly relates to a deinking agent and deinking process for thermal transfer waste paper. Background Technology

[0002] In the field of digital printing, polyester heat transfer printing technology has been widely used due to its waterless, clean, and short production time. However, in the production process, the heat transfer paper, as a consumable, can only be disposed of as solid waste after printing, resulting in serious waste of paper.

[0003] After printing, heat transfer paper retains a certain amount of disperse dyes, dispersing agents, coating materials, and other impurities. If these are not deinked and cleaned, they will severely impact the paper's reusability, affecting aspects such as whiteness and strength. Existing deinking agents (such as CN104693880A and CN105331180A) are primarily used for deinking waste paper such as newspapers and printing paper. However, the ink composition used in newspapers and printing paper is completely different from the dyes remaining on heat transfer waste paper. Therefore, existing deinking agents are not suitable for deinking existing heat transfer waste paper. Furthermore, the inks used in existing newspapers and color printing paper are non-water-soluble and contain a large amount of binder. Therefore, existing newspapers and color printing paper use flotation deinking processes, requiring deinking agent formulations that adsorb, capture, and float ink particles. Existing deinking agents are mainly formulated with low-water-soluble surfactants, such as fatty acids, fatty acid esters, fatty acid polyoxyethylene polyoxypropylene ethers, and soap powder, supplemented with penetrating and foaming anionic surfactants, such as sodium dodecylbenzene sulfonate and sodium olefin sulfonate. However, the surfactants in existing formulations have very limited ability to remove disperse dyes and are not suitable for deinking thermal transfer paper.

[0004] Therefore, in order to effectively recycle and utilize heat transfer paper (such as dispersed heat transfer paper), it is urgent to develop a deinking agent and deinking process suitable for heat transfer paper. Summary of the Invention

[0005] In order to overcome the problems existing in the prior art, one of the objectives of the present invention is to provide a deinking agent for heat transfer waste paper, which can effectively remove ink from heat transfer waste paper and improve the whiteness of recycled paper.

[0006] The second objective of this invention is to provide a method for preparing the above-mentioned deinking agent.

[0007] The third objective of this invention is to provide a deinking process for waste paper used in thermal transfer printing.

[0008] The fourth objective of this invention is to provide a recyclable paper.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A first aspect of the present invention provides a deinking agent for thermal transfer waste paper, comprising a solubilizer, a surfactant, and a penetrant;

[0011] The solubilizer is selected from polyester; the polyester contains a condensation structure of ethylene glycol phthalate.

[0012] The surfactant includes at least one of styrene-phenol polyoxyethylene, sodium styrene-phenol polyoxyethylene sulfate, glyceryl ether oleate, or oleic acid polyoxyethylene ester;

[0013] The penetrant includes at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, or ethylene glycol phenyl ether.

[0014] In the deinking agent of this invention, the solubilizer is selected from polyester, which contains a ethylene glycol phthalate condensation structure, exhibiting extremely high affinity for disperse dyes and effectively solubilizing residual disperse dyes on heat transfer paper. The surfactant includes at least one of styrene-phenol polyoxyethylene, sodium styrene-phenol polyoxyethylene sulfate, glyceryl ether oleate, or oleic acid polyoxyethylene ester. These surfactants, due to the presence of benzene rings and ester groups in their molecular structure, also have high affinity for disperse dyes and can effectively emulsify them. Simultaneously, the surfactant can improve the permeability of the working solution to pulp fibers, thereby increasing the removal efficiency of disperse dyes and hydrophobic impurities. The penetrant includes at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, or ethylene glycol phenyl ether, primarily to enhance the penetration and stripping of insoluble colloids by the working solution.

[0015] Preferably, the polyester in the deinking agent includes water-soluble polyester, water-dispersible polyester, or a combination thereof.

[0016] Preferably, the water-dispersible polyester is prepared from phthalic acid, ethylene glycol and polyether.

[0017] Preferably, in the raw materials for preparing the water-dispersible polyester, the phthalic acid includes at least one of terephthalic acid, isophthalic acid, or phthalic acid; more preferably, it includes terephthalic acid, isophthalic acid, or a combination thereof.

[0018] Preferably, the water-soluble polyester is prepared from phthalic acid, ethylene glycol, hydrophilic monomers and polyether.

[0019] Preferably, the hydrophilic monomers in the raw materials for preparing the water-soluble polyester include at least one of trimellitic anhydride, dimethylolpropionic acid, or sulfonate; more preferably, sulfonate.

[0020] Preferably, the sulfonate includes at least one of isophthalic acid-5-sulfonate, succinic anhydride sulfonate, or dimethyl isophthalate-5-sulfonate; more preferably, dimethyl isophthalate-5-sulfonate; and even more preferably, sodium dimethyl isophthalate-5-sulfonate.

[0021] Preferably, in the raw materials for preparing the water-soluble polyester, the phthalic acid includes at least one of terephthalic acid, isophthalic acid, or phthalic acid; more preferably, it includes terephthalic acid, isophthalic acid, or a combination thereof.

[0022] Preferably, the surfactant in the deinking agent includes at least one of styrene-phenol polyoxyethylene, glyceryl ether oleate, or oleic acid polyoxyethylene ester; more preferably, it includes styrene-phenol polyoxyethylene, oleic acid polyoxyethylene ester, or a combination thereof.

[0023] Preferably, the penetrant in the deinking agent includes diethylene glycol butyl ether, ethylene glycol phenyl ether, or a combination thereof.

[0024] Preferably, in the deinking agent, the mass ratio of solubilizer to surfactant is 1:(0.3-3); more preferably 1:(0.5-2); and even more preferably 1:(0.8-1.2).

[0025] Preferably, the mass ratio of the solubilizer to the penetrant in the deinking agent is 1:(0.15-1); more preferably 1:(0.3-0.8); and even more preferably 1:(0.4-0.6).

[0026] Preferably, in the deinking agent, the mass ratio of solubilizer, surfactant and penetrant is 1:(0.3-3):(0.15-1); more preferably 1:(0.5-2):(0.3-0.8); and even more preferably 1:(0.8-1.2):(0.4-0.6).

[0027] Preferably, the deinking agent further includes water, and the mass ratio of the solubilizer to the water is 1:(1-10); more preferably 1:(1.2-8); and even more preferably 1:(1.5-6).

[0028] Preferably, in the deinking agent, the mass ratio of solubilizer, surfactant, penetrant and water is 1:(0.3-3):(0.15-1):(1-10); more preferably 1:(0.5-2):(0.3-0.8):(1.2-8); even more preferably 1:(0.8-1.2):(0.4-0.6):(1.5-6).

[0029] A second aspect of the present invention provides a method for preparing the deinking agent described in the first aspect of the present invention, comprising the following steps: mixing the components of the deinking agent at 60-100°C to obtain the deinking agent.

[0030] Preferably, in the preparation method of the deinking agent, the mixing temperature of each component is 70-90°C; more preferably, it is 75-85°C.

[0031] A third aspect of the present invention provides a deinking process for thermal transfer waste paper, comprising the following steps: mixing thermal transfer waste paper pulp with an alkali agent and a deinking agent A, heating, keeping warm, and removing the liquid phase to obtain a deinked pulp cake; wherein the deinking agent A is selected from the deinking agents described in the first aspect of the present invention.

[0032] Preferably, in the deinking process, the heat transfer waste paper pulp is prepared by a method including the following steps: pulverizing the heat transfer waste paper and soaking it in water, then dissolving it to obtain the heat transfer waste paper pulp.

[0033] Preferably, in the method for preparing the heat transfer waste paper pulp, the mass ratio of the heat transfer waste paper to the water is 1:(1-5); more preferably, it is 1:(2-4).

[0034] Preferably, in the method for preparing the heat transfer waste paper pulp, the soaking temperature is 20-30°C; more preferably, it is 24-26°C.

[0035] Preferably, in the method for preparing the heat transfer waste paper pulp, the crushing involves crushing the waste paper into fragments of (0.5-2)cm × (0.5-2)cm.

[0036] Preferably, in the method for preparing the heat transfer waste paper pulp, the disintegration method is selected from pulverizing using a pulverizer.

[0037] Preferably, in the deinking process, the alkali agent includes at least one of sodium carbonate, sodium bicarbonate, potassium carbonate, or potassium bicarbonate.

[0038] Preferably, in the deinking process, the mass ratio of solid content of thermal transfer waste paper pulp to alkali agent is 10:(0.1-1); more preferably 10:(0.15-0.9); and even more preferably 10:(0.2-0.8).

[0039] Preferably, in the deinking process, the mass ratio of the solid content of the thermal transfer waste paper pulp to the deinking agent is 10:(0.1-1); more preferably 10:(0.15-0.9); and even more preferably 10:(0.2-0.8).

[0040] Preferably, in the deinking process, the solid content of the thermal transfer waste paper pulp and the mass ratio of alkali agent to deinking agent A are 10:(0.1~1):(0.1~1); more preferably 10:(0.15~0.9):(0.15~0.9); even more preferably 10:(0.2~0.8):(0.2~0.8).

[0041] Preferably, the temperature for heat preservation in the deinking process is 50–100°C; more preferably 60–90°C.

[0042] Preferably, the heat preservation time in the deinking process is 10-40 minutes; more preferably, it is 20-30 minutes.

[0043] Preferably, in the deinking process, the method of removing the liquid phase includes at least one of filtration, pressure filtration, and drying; more preferably, pressure filtration.

[0044] In a specific embodiment of the present invention, if there is a large amount of residual ink in the waste paper pulp from heat transfer printing, the steps of mixing with the alkali agent and deinking agent A, heating, heat preservation, and removing the liquid phase in the deinking process can be repeated. Preferably, the steps of mixing with the alkali agent and deinking agent A, heating, heat preservation, and removing the liquid phase are used 1 to 10 times; more preferably 1 to 5 times.

[0045] In a specific embodiment of the present invention, if there is a large amount of residual ink in the waste paper pulp from heat transfer printing, the deinking process further includes a deep deinking step.

[0046] Preferably, the deep deinking step is as follows: the deinked pulp cake is mixed with water, hydrogen peroxide, sodium hydroxide, and deinking agent B, matured, and the liquid phase is removed to obtain a deeply deinked pulp cake; the deinking agent B is selected from the deinking agent described in the first aspect of the present invention.

[0047] Deinking agent A and deinking agent B are each independently selected from the deinking agents described in the first aspect of the present invention. Deinking agent A and deinking agent B may have the same or different antioxidant properties.

[0048] Preferably, in the deep deinking step, the deinked pulp cake is first mixed with water to obtain pulp, and then mixed with hydrogen peroxide, sodium hydroxide and deinking agent B.

[0049] Preferably, in the deep deinking step, the mass ratio of the deinked pulp cake to water is 1:(1-5); more preferably 1:(0.5-3); and even more preferably 1:(0.8-1.2).

[0050] Preferably, in the deep deinking step, the mass ratio of the deinked pulp cake to hydrogen peroxide is 10:(0.3-0.8); more preferably 10:(0.35-0.7); and even more preferably 10:(0.4-0.6).

[0051] Preferably, in the deep deinking step, the mass concentration of hydrogen peroxide is 40-60 wt%; more preferably 45-55 wt%.

[0052] Preferably, in the deep deinking step, the mass ratio of the deinked pulp cake to sodium hydroxide is 10:(0.3-0.8); more preferably 10:(0.35-0.7); and even more preferably 10:(0.4-0.6).

[0053] Preferably, in the deep deinking step, the mass ratio of the deinked pulp cake to the deinking agent B is 10:(0.1-0.5); more preferably 10:(0.15-0.4); and even more preferably 10:(0.18-0.3).

[0054] Preferably, in the deep deinking step, the curing temperature is 50–70°C; more preferably, it is 55–65°C.

[0055] Preferably, the curing time in the deep deinking step is 50-70 minutes; more preferably, it is 55-65 minutes.

[0056] Preferably, in the deep deinking step, the method of removing the liquid phase includes at least one of filtration, pressure filtration, and drying.

[0057] Preferably, in the deep deinking step, washing is performed after removing the liquid phase; the number of washing cycles is 3 to 7; and the washing method is to use a 60 to 100 mesh mesh bag for washing.

[0058] A fourth aspect of the present invention provides a recycled paper obtained by deinking with the deinking agent described in the first aspect of the present invention, or by the deinking process described in the third aspect of the present invention.

[0059] Preferably, the whiteness of the recycled paper is 62-80%; more preferably 65-78%; and even more preferably 68-76%.

[0060] The beneficial effects of this invention are: through the synergistic effect of specific solubilizers, surfactants and penetrants, the deinking agent obtained by this invention has a good affinity for disperse dyes and hydrophobic impurities, and can effectively encapsulate, emulsify and penetrate the inks such as disperse dyes and hydrophobic impurities remaining on thermal transfer waste paper, thereby achieving effective removal of residual inks on thermal transfer waste paper and improving the whiteness of recycled paper. Attached Figure Description

[0061] Figure 1 This is a physical image of the heat transfer waste paper 1 used in Example 1.

[0062] Figure 2 This is a physical image of the heat transfer waste paper 2 used in Example 2.

[0063] Figure 3 This is a physical image of the heat transfer waste paper 3 used in Example 3.

[0064] Figure 4 This is a physical image of the heat transfer waste paper 4 used in Example 4. Detailed Implementation

[0065] The following specific embodiments further illustrate the content of the present invention in detail. It should also be understood that the following embodiments are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art based on the principles described herein are all within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make selections within a suitable range based on the description herein, and are not intended to be limited to the specific data in the examples below. Unless otherwise specified, the raw materials, reagents, or apparatus used in the following embodiments and comparative examples can be obtained from conventional commercial sources or by existing known methods.

[0066] In a specific embodiment of the present invention, the water-soluble polyester was purchased from Zhejiang Kezelin Technology Co., Ltd., with trade name FY01; the water-dispersible polyester was purchased from Zhangjiagang Debao Chemical Co., Ltd., with trade name DP998B.

[0067] Example 1

[0068] This example provides a deinking agent 1 for thermal transfer waste paper, comprising the following components in parts by weight: 10 parts water-soluble polyester, 10 parts styrene-phenol polyoxyethylene ether, 5 parts diethylene glycol butyl ether, and 60 parts water.

[0069] The preparation method of deinking agent 1 described in this example includes the following steps: weigh each component of deinking agent 1, heat to 80°C, stir and dissolve to obtain deinking agent 1.

[0070] Application Example 1

[0071] This example provides a deinking process for waste paper from thermal transfer printing, including the following steps:

[0072] Take 10kg of waste heat transfer paper 1 (see actual picture of waste heat transfer paper 1). Figure 1As shown, the waste paper is shredded into small pieces of 0.8cm × 0.8cm using a paper shredder, mixed evenly, and then soaked in 20kg of water for 30 minutes to allow the waste paper to fully absorb water and swell. Then, it is pulped using a disc shredder. 0.2kg of sodium bicarbonate and 0.2kg of deinking agent 1 are added to the waste paper pulp, the temperature is raised to 80℃ and maintained for 30 minutes, and the residue is removed by pressure filtration to obtain deinked pulp cake 1.

[0073] Example 2

[0074] This example provides a deinking agent 2 for thermal transfer waste paper, comprising the following components in parts by weight: 20 parts water-dispersible polyester, 10 parts styrene-phenol polyoxyethylene ether, 2.5 parts ethylene glycol phenyl ether, and 50 parts water.

[0075] The preparation method of deinking agent 2 described in this example includes the following steps: weigh each component of deinking agent 2, heat to 80°C, stir to dissolve, and prepare deinking agent 2.

[0076] Application Example 2

[0077] This example provides a deinking process for waste paper from thermal transfer printing, including the following steps:

[0078] Take 10kg of waste heat transfer paper 2 (see actual picture of waste heat transfer paper 2). Figure 2 As shown, the waste paper is shredded into small pieces of 0.8cm × 0.8cm using a paper shredder, mixed evenly, and then soaked in 30kg of water for 30 minutes to allow the waste paper to fully absorb water and swell. Then, it is pulped using a disc shredder. 0.8kg of sodium bicarbonate and 0.5kg of deinking agent 2 are added to the waste paper pulp, the temperature is raised to 60℃ and maintained for 30 minutes, and the residue is removed by pressure filtration to obtain deinked pulp cake 2.

[0079] Example 3

[0080] This example provides a deinking agent 3 for thermal transfer waste paper, comprising the following components in parts by weight: 30 parts water-soluble polyester, 10 parts oleic acid polyoxyethylene ester, 5 parts diethylene glycol butyl ether, and 60 parts water.

[0081] The preparation method of deinking agent 3 described in this example includes the following steps: weigh each component of deinking agent 3, heat to 80°C, stir to dissolve, and prepare deinking agent 3.

[0082] Application Example 3

[0083] This example provides a deinking process for waste paper from thermal transfer printing, including the following steps:

[0084] Take 10kg of waste heat transfer paper 3 (see actual picture of waste heat transfer paper 3). Figure 3As shown, the waste paper is shredded into small pieces of 0.8cm × 0.8cm using a paper shredder, mixed evenly, and then soaked in 25kg of water for 30 minutes to allow the waste paper to fully absorb water and swell. Then, it is pulped using a disc shredder. 0.5kg of potassium carbonate and 0.5kg of deinking agent 3 are added to the waste paper pulp, the temperature is raised to 60℃ and held for 30 minutes, then filtered to remove residual liquid, yielding a pulp cake.

[0085] The pulp cake was redispersed in 10 kg of water, and 0.5 kg of potassium carbonate and 0.5 kg of deinking agent 3 were added. The temperature was raised to 60°C and kept for 30 min. The residue was removed by pressure filtration to obtain the deinked pulp cake 3.

[0086] Example 4

[0087] This example provides a deinking agent 4 for thermal transfer waste paper, comprising the following components in parts by weight: 30 parts water-dispersible polyester, 20 parts styrene-phenol polyoxyethylene ether, 7 parts diethylene glycol butyl ether, and 50 parts water.

[0088] The preparation method of deinking agent 4 described in this example includes the following steps: weigh each component of deinking agent 4, heat to 80°C, stir to dissolve, and obtain deinking agent 4.

[0089] Application Example 4

[0090] This example provides a deinking process for waste paper from thermal transfer printing, including the following steps:

[0091] Take 10kg of waste heat transfer paper 4 (see actual picture of waste heat transfer paper 4). Figure 4 As shown, the waste paper is shredded into small pieces of 0.8cm × 0.8cm using a paper shredder, mixed evenly, and then soaked in 25kg of water for 30 minutes to allow the waste paper to fully absorb water and swell. Then, it is pulped using a disc shredder. 0.5kg of potassium carbonate and 0.5kg of deinking agent 4 are added to the waste paper pulp, the temperature is raised to 70℃ and maintained for 25 minutes, then filtered to remove residual liquid, yielding a pulp cake.

[0092] The pulp cake was redispersed in 10 kg of water, and 0.8 kg of sodium carbonate and 0.8 kg of deinking agent 4 were added. The temperature was raised to 70°C and kept at that temperature for 25 minutes. The residue was removed by pressure filtration to obtain the deinked pulp cake.

[0093] The deinked pulp cake was dispersed in 10 kg of water, and 0.5 kg of sodium hydroxide, 0.5 kg of hydrogen peroxide (50 wt%), and 0.2 kg of deinking agent 4 were added. The mixture was heated to 60°C and kept at that temperature for 60 min. The pulp cake was then washed 5 times with an 80-mesh mesh bag to obtain a deeply deinked pulp cake 4.

[0094] Application Comparative Example 1

[0095] This example provides a deinking process for waste paper from thermal transfer printing, including the following steps:

[0096] Take commercially available deinking agent (manufacturer: Tianjin Xiongguan Technology Development Co., Ltd., main component: fatty alcohol polyoxyethylene ether) and deink the heat transfer waste paper 4 according to the steps of Example 4 to obtain pulp cake 5.

[0097] Application Comparative Example 2

[0098] To verify the synergistic effect in the deinking agent formulation, this example provides a comparative example comprising the following components in parts by weight: 50 parts water-dispersible polyester, 7 parts diethylene glycol butyl ether, and 50 parts water. Thermal transfer waste paper 4 was deinked according to the steps of Example 4 to obtain pulp cake 6.

[0099] Application Comparative Example 3

[0100] To verify the synergistic effect in the deinking agent formulation, this example provides a comparative example comprising the following components in parts by weight: 30 parts water-soluble polyester, 27 parts diethylene glycol butyl ether, and 50 parts water. Thermal transfer waste paper 4 was deinked according to the steps of Example 4 to obtain pulp cake 7.

[0101] The whiteness of pulp cakes 1-7 obtained from Application Examples 1-4 and Comparative Examples 1-3 was measured according to GB / T7974-2013. The data obtained are recorded in Table 1.

[0102] Table 1. Whiteness of pulp cakes 1-7

[0103] WhitenessISO% Application Example 1 70.7 Application Example 2 71.9 Application Example 3 69.3 Application Example 4 75.6 Application Comparative Example 1 60.6 Application Comparative Example 2 64.4 Application Comparative Example 3 66.7

[0104] As shown in Table 1 above, compared with commercially available traditional deinking agents, the deinking agent and deinking process of this invention can effectively improve the whiteness of thermal transfer waste paper. The whiteness of application examples 1-4 is 69.3-75.6%, while in the comparative examples, the whiteness of commercially available products is only 60.6%. Commercially available deinking agents mainly use surfactants such as fatty alcohol polyoxyethylene ethers, which mainly play a role in penetration and wetting. They have low affinity for disperse dyes, so their deinking effect on thermal transfer waste paper is much lower than that of this invention. Comparative examples 2-3 demonstrate that there is a certain synergistic effect among the solubilizer, surfactant, and penetrant in the formulation.

[0105] This invention utilizes the synergistic effect of specific solubilizers, surfactants, and penetrants to obtain a deinking agent that exhibits excellent affinity for disperse dyes and hydrophobic impurities. This agent effectively compatibilizes, emulsifies, and penetrates residual disperse dyes and hydrophobic impurities in thermal transfer waste paper, thereby achieving effective removal of residual ink from thermal transfer waste paper and improving the whiteness of recycled paper.

Claims

1. A deinking agent for heat transfer waste paper, characterized in that, It consists of solubilizer, surfactant, penetrant and water; The solubilizer is selected from polyester; the polyester contains a ethylene glycol phthalate condensation structure; the polyester is selected from water-soluble polyester; the water-soluble polyester is prepared from phthalic acid, ethylene glycol, hydrophilic monomers and polyethers; the hydrophilic monomers are selected from sulfonates; the sulfonate is selected from sodium dimethyl isophthalate-5-sulfonate. The surfactant includes at least one of styrene-phenol polyoxyethylene, sodium styrene-phenol polyoxyethylene sulfate, glyceryl ether oleate, or oleic acid polyoxyethylene ester; The penetrant includes at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, or ethylene glycol phenyl ether; The mass ratio of the solubilizer to the surfactant is 1:(0.3~3); the mass ratio of the solubilizer to the penetrant is 1:(0.15~1); the mass ratio of the solubilizer to the water is 1:(1~10). The deinking agent is prepared by a method comprising the following steps: mixing the components of the deinking agent at 60~100°C to obtain the deinking agent.

2. The method for preparing the deinking agent according to claim 1, characterized in that, The components of the deinking agent are mixed at 60~100℃ to obtain the deinking agent.

3. A deinking process for waste paper used in thermal transfer printing, characterized in that, Includes the following steps: The waste paper pulp from heat transfer printing is mixed with an alkali agent and deinking agent A, heated, kept at a constant temperature, and the liquid phase is removed to obtain a deinked pulp cake; the deinking agent A is selected from the deinking agent described in claim 1.

4. The deinking process according to claim 3, characterized in that, The alkaline agent includes at least one of sodium carbonate, sodium bicarbonate, potassium carbonate, or potassium bicarbonate. And / or, the mass ratio of the solid content of the heat transfer waste paper pulp to the alkali agent is 10:(0.1~1). And / or, the solid content of the heat transfer waste paper pulp to the mass ratio of deinking agent A is 10:(0.1~1). And / or, the insulation temperature is 50~100℃; And / or, the heat preservation time is 10~40 min.

5. The deinking process according to claim 3, characterized in that, It also includes a deep deinking step, which involves mixing the deinked pulp cake with water, hydrogen peroxide, sodium hydroxide, and deinking agent B, maturing the mixture, and removing the liquid phase to obtain a deeply deinked pulp cake; the deinking agent B is selected from the deinking agent described in claim 1.

6. The deinking process according to claim 5, characterized in that, The mass ratio of the deinked pulp cake to water is 1:(1~5). And / or, the mass ratio of the deinked pulp cake to hydrogen peroxide is 10:(0.3~0.8). And / or, the mass ratio of the deinked pulp cake to sodium hydroxide is 10:(0.3~0.8). And / or, the mass ratio of the deinked pulp cake to deinking agent B is 10:(0.1~0.5). And / or, the ripening temperature is 50~70°C; And / or, the ripening time is 50-70 minutes.

7. A type of recycled paper, characterized in that, It is obtained by deinking the deinking agent according to claim 1, or by the deinking process according to any one of claims 3 to 6.

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