A light cationic polymer fatliquoring agent and a preparation method thereof

Abstract

The present application provides a light cationic polymer fatliquor, the polymerized monomers of which comprise: unsaturated polyether, cationic monomer, single-end methacryloyloxypropyl polysiloxane and dodecyl acrylate. The light cationic polymer fatliquor prepared by the present application can be used in the chrome tanning process. In addition to the acid resistance, chrome salt resistance and good color fixing effect possessed by the cationic fatliquor, the light cationic polymer fatliquor also has excellent collagen fiber dispersing effect, can greatly reduce the use of subsequent oil fatliquor, effectively reduces the cost of leather making, and at the same time, gives the leather soft and light touch, and is very suitable for the production of light weight leather products.

Description

Technical Field

[0001] This invention relates to the field of leather fatliquoring technology, and in particular to a lightweight cationic polymer fatliquoring agent and its preparation method. Background Technology

[0002] Cationic fatliquoring agents are important leather conditioning materials in the production of lightweight leather. They possess acid and chromium salt resistance properties and can be used in the chrome tanning process to increase the leather's softness. They can also be used for top-layer fatliquoring to give the leather a better surface feel. Most existing cationic fatliquoring agents are small-molecule modified oils or compounded with cationic surfactants. These materials have problems such as weak bonding to leather fibers, poor water resistance of the finished product, poor resistance to yellowing, and an excessively oily feel.

[0003] Currently, leather products such as garment leather, glove leather, and car seat leather are increasingly seeking lightweight and washable properties. Polymer retanning and fatliquoring agents, because they combine retanning and fatliquoring functions, can replace both retanning and fatliquoring agents, reducing the use of chemicals. Furthermore, they produce leather with a lower oiliness, making them a preferred material for preparing lightweight leather products. Currently, anionic polymer retanning and fatliquoring agents are the most common, while cationic polymer fatliquoring agents have received less research. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a lightweight cationic polymer fatliquoring agent and its preparation method, which has excellent dispersing effect on collagen fibers.

[0005] To achieve the above objectives, the present invention provides a lightweight cationic polymer fatliquoring agent, wherein the polymer monomers include: unsaturated polyether, cationic monomer, single-terminated methacryloyloxypropyl polysiloxane, and dodecyl acrylate.

[0006] Optionally, the unsaturated polyether is selected from allyl polyether or methoxy polyethylene glycol methacrylate.

[0007] This invention uses unsaturated polyether as a monomer. The polyether segments are grafted onto the polymer side chains through free radical polymerization, which can improve the water solubility of the polymer and is beneficial to improving the stability of the cationic polymer.

[0008] The number of EO atoms in the unsaturated polyether is preferably between 10 and 30. If the number of EO atoms is too low, the emulsion stability is poor; if the number of EO atoms is too high, the unsaturated polyether has low activity and is difficult to polymerize.

[0009] Optionally, the cationic monomer is selected from methacryloyloxyethyltrimethylammonium chloride or dimethylaminoethyl methacrylate.

[0010] The present invention selects the above-mentioned cationic monomers to endow the polymer with acid resistance and chromium salt resistance, and also promotes the fixation and absorption of subsequent anionic materials and improves color fixation.

[0011] Optionally, the single-terminated methacryloyloxypropyl polysiloxane has the structure shown in Formula I:

[0012]

[0013] Where n is between 10 and 37.

[0014] This invention introduces the above-mentioned single-terminated methacryloyloxypropyl polysiloxane, which utilizes the excellent lubrication ability of siloxane to improve the soft and light feel of the outer shell.

[0015] Preferably, the number average molecular weight of the above-mentioned single-terminated methacryloyloxypropyl polysiloxane is 1000-3000. If the molecular weight is below 1000, the improvement effect is not significant; if the molecular weight is above 3000, the polymerization activity of the single-terminated methacryloyloxypropyl polysiloxane is low, making grafting difficult.

[0016] This invention also introduces dodecyl acrylate into the polymer structure to improve the ability to disperse fibers. If the carbon chain is too short, such as isooctyl acrylate, the softness of the preform will be insufficient after application; if the carbon chain is too long, such as octadecyl acrylate, the monomer activity will be low and it will be difficult to polymerize. Dodecyl acrylate has the best application effect.

[0017] Optionally, the weight ratio of the unsaturated polyether, cationic monomer, single-terminated methacryloyloxypropyl polysiloxane and dodecyl acrylate is (5-20):(10-35):(5-30):(20-50).

[0018] This invention provides a method for preparing the above-mentioned lightweight cationic polymer fatliquoring agent, comprising the following steps:

[0019] S1) Preparation of monomer emulsion: After the first cationic emulsifier is evenly dispersed in an aqueous solution, it is mixed with unsaturated polyether, cationic monomer, single-terminated methacryloyloxypropyl polysiloxane, dodecyl acrylate and chain transfer agent, and emulsified to obtain monomer emulsion.

[0020] S2) Preparation of seed emulsion: After the second cationic emulsifier and glacial acetic acid are evenly dispersed in an aqueous solution, they are mixed with a portion of monomer emulsion and the first cationic initiator to carry out the first polymerization reaction and obtain seed emulsion;

[0021] S3) Preparation of cationic emulsion: The seed emulsion, the remaining monomer emulsion, and the second cationic initiator are mixed and subjected to a second polymerization reaction to obtain a light cationic polymer fatliquoring agent.

[0022] Optionally, the first cationic emulsifier and the second cationic emulsifier are independently selected from any one of dodecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, and hexadecyltrimethylammonium chloride.

[0023] In some specific embodiments of the present invention, the first cationic emulsifier and the second cationic emulsifier described above are the same.

[0024] Optionally, the chain transfer agent is selected from mercaptoethanol or n-dodecyl mercaptan.

[0025] Optionally, the first cationic initiator and the second cationic initiator are independently selected from azobisisobutylamidine hydrochloride or azobisisopropylimidazoline hydrochloride.

[0026] In some specific embodiments of the present invention, the first cationic initiator and the second cationic initiator are the same.

[0027] Optionally, the amount of unsaturated polyether added is 5 to 20 parts by weight.

[0028] Optionally, the amount of the cationic monomer added is 10 to 35 parts by weight.

[0029] Optionally, the amount of the single-terminated methacryloyloxypropyl polysiloxane added is 5 to 30 parts by weight.

[0030] Optionally, the amount of dodecyl acrylate added is 20 to 50 parts by weight.

[0031] Optionally, the amount of chain transfer agent added is 0.1 to 5 parts by weight.

[0032] This invention incorporates a chain transfer agent during the preparation process, which improves permeability and fiber dispersion by reducing the polymer molecular weight. Without the chain transfer agent, the leather treated with the fatliquoring agent is prone to sticking and its softness deteriorates.

[0033] Optionally, the amount of the first cationic emulsifier added is 1 to 3 parts by weight.

[0034] Optionally, the amount of the second cationic emulsifier added is 0.2 to 1 part by weight.

[0035] Optionally, the amount of glacial acetic acid added is 0.2 to 1 part by weight.

[0036] The present invention introduces an appropriate amount of glacial acetic acid into the system, which can endow the polymer with acid resistance and chromium salt resistance, and also promote the fixation and absorption of subsequent anionic materials and improve the color fixation effect.

[0037] Optionally, the amount of the monomer emulsion added is 5% to 10% of the total amount of monomer emulsion.

[0038] Optionally, the amount of the first cationic initiator added is 0.1 to 0.5 parts by weight.

[0039] Optionally, the amount of the second cationic initiator added is 0.5 to 2 parts by weight.

[0040] Optionally, the amount of aqueous solution used in step S1) above is 50 parts by weight.

[0041] Optionally, in step S1) above, after the first cationic emulsifier and the aqueous solution are mixed, they are dispersed at 300-600 RPM for 5 minutes to ensure that the first cationic emulsifier is evenly dispersed in the aqueous solution.

[0042] After adding unsaturated polyether, cationic monomer, single-terminated methacryloyloxypropyl polysiloxane, dodecyl acrylate, and chain transfer agent, emulsify at high speed for at least 15 minutes to ensure uniform dispersion of the monomer.

[0043] Optionally, the amount of aqueous solution used in step S2) above is 168.33 parts by weight.

[0044] Optionally, in step S2) above, after the second cationic emulsifier, glacial acetic acid and aqueous solution are mixed, they are dispersed at 50 RPM for 10 min, while the temperature is raised to the reaction temperature to ensure that the second cationic emulsifier is evenly dispersed.

[0045] Optionally, the temperature of the first polymerization reaction is 80-85℃ and the time is 10 min.

[0046] Optionally, in step S3) above, the second cationic initiator is dissolved in water to form a solution. The amount of water used is 15 parts by weight.

[0047] Optionally, the remaining monomer emulsion and the second cationic initiator are added dropwise to the reaction system.

[0048] Preferably, the remaining monomer emulsion is added dropwise over 240 minutes.

[0049] Preferably, the second cationic initiator is added dropwise in the form of an aqueous solution over 300 minutes.

[0050] Optionally, the temperature of the second polymerization reaction is 80-85℃ and the time is 360 min.

[0051] After the reaction is complete, the system is cooled to below 40°C to obtain the above-mentioned lightweight cationic polymer fatliquoring agent.

[0052] The solid content of the lightweight cationic polymer fatliquoring agent prepared by this invention is preferably 30% or more.

[0053] Compared with existing technologies, this invention provides a lightweight cationic polymer fatliquoring agent, whose polymer monomers include: unsaturated polyether, cationic monomer, single-terminated methacryloxypropyl polysiloxane, and dodecyl acrylate. The lightweight cationic polymer fatliquoring agent prepared by this invention can be used in the chrome tanning process. In addition to the good acid resistance, chromium salt resistance, and color-fixing effect of cationic fatliquoring agents, it also has excellent collagen fiber dispersion properties, which can significantly reduce the use of subsequent oil-based fatliquoring agents, effectively reducing leather tanning costs, while giving the leather a soft and lightweight feel, making it very suitable for the production of lightweight leather products. Detailed Implementation

[0054] To further illustrate the present invention, the following detailed description of the lightweight cationic polymer fatliquoring agent and its preparation method provided by the present invention is provided in conjunction with embodiments.

[0055] Example 1

[0056] Monomer emulsion preparation: 50 parts water and 1 part dodecyltrimethylammonium chloride were added to an emulsification tank and dispersed at 300 RPM for 5 min. Then, 19.4 parts allyl polyether (EO number 10), 30 parts methacryloyloxyethyltrimethylammonium chloride, 5 parts monomethacryloyloxypropyl polysiloxane (molecular weight approximately 1000), 40 parts dodecyl acrylate, and 0.1 parts mercaptoethanol were added sequentially, and emulsified at high speed for at least 15 min to obtain the monomer emulsion.

[0057] Seed emulsion preparation: 168.33 parts water, 1 part dodecyltrimethylammonium chloride and 1 part glacial acetic acid were added to the reaction vessel and dispersed at 50 RPM for 10 min while the temperature was raised to 80℃. After the dispersion time was up, 5% monomer emulsion was added and 0.5 parts azobisisobutylamidine hydrochloride was added to initiate the reaction. The reaction was kept at this temperature for 10 min to prepare the seed emulsion.

[0058] Cationic emulsion preparation: After the heat treatment, the remaining monomer emulsion and 2 parts of azobisisobutylamidine hydrochloride solution (dissolved in 15 parts of water) were added dropwise to the reactor. The monomer emulsion was added over 240 minutes, and the cationic initiator solution was added over 300 minutes. After the initiator was added, the temperature was raised to 85°C and held for 1 hour. Then the temperature was lowered to below 40°C, filtered, and discharged.

[0059] Example 2

[0060] Monomer emulsion preparation: 50 parts water and 2 parts hexadecyltrimethylammonium chloride were added to an emulsification tank and dispersed at 400 RPM for 5 min. Then, 10 parts allyl polyether (EO number 20), 19.8 parts dimethylaminoethyl methacrylate, 15 parts monomethacryloyloxypropyl polysiloxane (molecular weight approximately 2000), 50 parts dodecyl acrylate, and 2 parts n-dodecyl mercaptan were added sequentially, and emulsified at high speed for at least 15 min to obtain the monomer emulsion.

[0061] Seed emulsion preparation: 168.33 parts water, 0.2 parts hexadecyltrimethylammonium chloride and 0.2 parts glacial acetic acid were added to the reaction vessel and dispersed at 50 RPM for 10 min while the temperature was raised to 80℃. After the dispersion time was up, 5% monomer emulsion was added and 0.3 parts azobisisopropylimidazoline hydrochloride was added to initiate the reaction. The mixture was kept at this temperature for 10 min to prepare the seed emulsion.

[0062] Cationic emulsion preparation: After the heat treatment, the remaining monomer emulsion and 0.5 parts of azobisisopropylimidazoline hydrochloride solution (dissolved in 15 parts of water) were added dropwise to the reactor. The monomer emulsion was added over 240 minutes, and the cationic initiator solution was added over 300 minutes. After the initiator was added, the temperature was raised to 85°C and held for 1 hour. Then the temperature was lowered to below 40°C, filtered, and discharged.

[0063] Example 3

[0064] Monomer emulsion preparation: 50 parts water and 3 parts dodecyltrimethylammonium chloride were added to an emulsification tank and dispersed at 600 RPM for 5 min. Then, 5 parts allyl polyether (EO number 30), 34.4 parts methacryloyloxyethyltrimethylammonium chloride, 30 parts monomethacryloyloxypropyl polysiloxane (molecular weight approximately 3000), 20 parts dodecyl acrylate, and 5 parts mercaptoethanol were added sequentially, and emulsified at high speed for at least 15 min to obtain the monomer emulsion.

[0065] Seed emulsion preparation: 168.33 parts water, 0.5 parts dodecyltrimethylammonium chloride and 0.5 parts glacial acetic acid were added to the reaction vessel and dispersed at 50 RPM for 10 min while the temperature was raised to 80℃. After the dispersion time was up, 5% monomer emulsion was added and 0.1 parts azobisisobutylamidine hydrochloride was added to initiate the reaction. The mixture was kept at this temperature for 10 min to prepare the seed emulsion.

[0066] Cationic emulsion preparation: After the incubation period, the remaining monomer emulsion and 1.5 parts of azobisisobutylamidine hydrochloride solution (dissolved in 15 parts of water) were added dropwise to the reactor. The monomer emulsion was added over 240 minutes, and the cationic initiator solution was added over 300 minutes. After the initiator was added, the temperature was raised to 85°C and held for 1 hour. Then the temperature was lowered to below 40°C, filtered, and discharged.

[0067] Comparative Example 1

[0068] Monomer emulsion preparation: 50 parts water and 3 parts dodecyltrimethylammonium chloride were added to an emulsification tank and dispersed at 600 RPM for 5 min. Then, 5 parts allyl polyether (EO number 30), 34.4 parts methacryloyloxyethyltrimethylammonium chloride, 0 parts monomethacryloyloxypropyl polysiloxane (molecular weight approximately 3000), 20 parts dodecyl acrylate, and 5 parts n-butyl 3-mercaptopropionate were added sequentially and emulsified at high speed for at least 15 min to obtain the monomer emulsion.

[0069] Seed emulsion preparation: 168.33 parts water, 0.5 parts dodecyltrimethylammonium chloride and 0.5 parts glacial acetic acid were added to the reaction vessel and dispersed at 50 RPM for 10 min while the temperature was raised to 80℃. After the dispersion time was up, 5% monomer emulsion was added and 0.1 parts azobisisobutylamidine hydrochloride was added to initiate the reaction. The mixture was kept at this temperature for 10 min to prepare the seed emulsion.

[0070] Cationic emulsion preparation: After the incubation period, the remaining monomer emulsion and 1.5 parts of azobisisobutylamidine hydrochloride solution (dissolved in 15 parts of water) were added dropwise to the reactor. The monomer emulsion was added over 240 minutes, and the cationic initiator solution was added over 300 minutes. After the initiator was added, the temperature was raised to 85°C and held for 1 hour. Then the temperature was lowered to below 40°C, filtered, and discharged.

[0071] Comparative Example 2

[0072] Monomer emulsion preparation: 50 parts water and 3 parts dodecyltrimethylammonium chloride were added to an emulsification tank and dispersed at 600 RPM for 5 min. Then, 5 parts allyl polyether (EO number 30), 34.4 parts methacryloyloxyethyltrimethylammonium chloride, 30 parts monomethacryloyloxypropyl polysiloxane (molecular weight approximately 3000), 20 parts dodecyl acrylate, and 0 parts 3-mercaptoethanol were added sequentially, and emulsified at high speed for at least 15 min to obtain the monomer emulsion.

[0073] Seed emulsion preparation: 168.33 parts water, 0.5 parts dodecyltrimethylammonium chloride and 0.5 parts glacial acetic acid were added to the reaction vessel and dispersed at 50 RPM for 10 min while the temperature was raised to 80℃. After the dispersion time was up, 5% monomer emulsion was added and 0.1 parts azobisisobutylamidine hydrochloride was added to initiate the reaction. The mixture was kept at this temperature for 10 min to prepare the seed emulsion.

[0074] Cationic emulsion preparation: After the incubation period, the remaining monomer emulsion and 1.5 parts of azobisisobutylamidine hydrochloride solution (dissolved in 15 parts of water) were added dropwise to the reactor. The monomer emulsion was added over 240 minutes, and the cationic initiator solution was added over 300 minutes. After the initiator was added, the temperature was raised to 85°C and held for 1 hour. Then the temperature was lowered to below 40°C, filtered, and discharged.

[0075] Performance testing:

[0076] The cationic polymer fatliquoring agents prepared in Examples 1-3 and Comparative Examples 1-2 were added to the chrome retanning process at an amount of 3% of the weight of the wet cowhide. The softness, foaminess, lightness, and surface color of the resulting cowhide leather were tested, and the results are shown in Table 1.

[0077] Table 1

[0078]

[0079] Softness: 1-5, the higher the level, the softer the product.

[0080] Foaming sensation: 1-5, the higher the level, the better the foaming sensation.

[0081] Lightness: Levels 1-5, the higher the level, the better the lightness.

[0082] Leather color: 1-5, the darker the color, the higher the score, indicating better color fixation effect.

[0083] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A lightweight cationic polymer fatliquoring agent, characterized in that, Its polymer monomers include: unsaturated polyethers, cationic monomers, single-terminated methacryloyloxypropyl polysiloxanes, and dodecyl acrylate; The weight ratio of the unsaturated polyether, cationic monomer, single-terminated methacryloyloxypropyl polysiloxane, and dodecyl acrylate is (5~20):(10~35):(5~30):(20~50). The preparation method of the lightweight cationic polymer fatliquoring agent includes the following steps: S1) Preparation of monomer emulsion: After the first cationic emulsifier is evenly dispersed in an aqueous solution, it is mixed with unsaturated polyether, cationic monomer, single-terminated methacryloyloxypropyl polysiloxane, dodecyl acrylate and chain transfer agent, and emulsified to obtain monomer emulsion. S2) Preparation of seed emulsion: After the second cationic emulsifier and glacial acetic acid are evenly dispersed in an aqueous solution, they are mixed with a portion of monomer emulsion and the first cationic initiator to carry out the first polymerization reaction and obtain seed emulsion; S3) Preparation of cationic emulsion: The seed emulsion, the remaining monomer emulsion, and the second cationic initiator are mixed and subjected to a second polymerization reaction to obtain a light cationic polymer fatliquoring agent; The chain transfer agent is selected from mercaptoethanol or n-dodecyl mercaptan.

2. The lightweight cationic polymer fatliquoring agent according to claim 1, characterized in that, The unsaturated polyether is selected from allyl polyether or methoxy polyethylene glycol methacrylate; The number of EO atoms in the unsaturated polyether is 10 to 30.

3. The lightweight cationic polymer fatliquoring agent according to claim 1, characterized in that, The cationic monomer is selected from methacryloyloxyethyltrimethylammonium chloride or dimethylaminoethyl methacrylate.

4. The lightweight cationic polymer fatliquoring agent according to claim 1, characterized in that, The single-terminated methacryloyloxypropyl polysiloxane has the structure shown in Formula I: Formula I; Where n is between 10 and 37.

5. The method for preparing the lightweight cationic polymer fatliquoring agent according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1) Preparation of monomer emulsion: After the first cationic emulsifier is evenly dispersed in an aqueous solution, it is mixed with unsaturated polyether, cationic monomer, single-terminated methacryloyloxypropyl polysiloxane, dodecyl acrylate and chain transfer agent, and emulsified to obtain monomer emulsion. S2) Preparation of seed emulsion: After the second cationic emulsifier and glacial acetic acid are evenly dispersed in an aqueous solution, they are mixed with a portion of monomer emulsion and the first cationic initiator to carry out the first polymerization reaction and obtain seed emulsion; S3) Preparation of cationic emulsion: The seed emulsion, the remaining monomer emulsion, and the second cationic initiator are mixed and subjected to a second polymerization reaction to obtain a light cationic polymer fatliquoring agent; The chain transfer agent is selected from mercaptoethanol or n-dodecyl mercaptan.

6. The preparation method according to claim 5, characterized in that, The first cationic emulsifier and the second cationic emulsifier are independently selected from any one of dodecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, and hexadecyltrimethylammonium chloride; The first cationic initiator and the second cationic initiator are independently selected from azobisisobutylamidine hydrochloride or azobisisopropylimidazoline hydrochloride.

7. The preparation method according to claim 5, characterized in that, The amount of unsaturated polyether added is 5 to 20 parts by weight; The amount of the cationic monomer added is 10-35 parts by weight; The amount of the single-terminated methacryloyloxypropyl polysiloxane added is 5 to 30 parts by weight. The amount of dodecyl acrylate added is 20-50 parts by weight; The amount of chain transfer agent added is 0.1 to 5 parts by weight; The amount of the first cationic emulsifier added is 1 to 3 parts by weight; The amount of the second cationic emulsifier added is 0.2 to 1 part by weight; The amount of glacial acetic acid added is 0.2 to 1 part by weight; The amount of the monomer emulsion added is 5% to 10% of the total amount of monomer emulsion; The amount of the first cationic initiator added is 0.1 to 0.5 parts by weight; The amount of the second cationic initiator added is 0.5 to 2 parts by weight.

8. The preparation method according to claim 5, characterized in that, The temperature of the first polymerization reaction is 80-85℃, and the time is 10 minutes.

9. The preparation method according to claim 5, characterized in that, The second polymerization reaction was carried out at a temperature of 80-85℃ for 360 minutes.

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