Emulsion type acrylic acid retanning agent and preparation method thereof

Abstract

An emulsion-type acrylic retanning agent and its preparation method relate to the technical field of leather chemical production. The preparation method involves reacting a fatty alcohol (acid) polyoxyethylene ether (ester) with maleic anhydride to obtain an intermediate, which is then copolymerized with a vinyl monomer in the reaction medium of water using persulfate in the presence of an emulsifier to obtain an emulsion product. The mass ratio of the intermediate to the vinyl monomer is 1.0:1.2-3.6, the reaction temperature is 80-95°C, the reaction time is 3-5 hours, the pH is 3-4, and the initiator dosage is 0.5-2.5% of the total mass of the intermediate and monomer. The finished product is stable and non-delaminated, simple to produce, low in cost, and produces leather that is plump, soft, and well-filled.

Description

Technical Field

[0001] The present invention relates to the technical field of leather chemical production, in particular to an emulsion type acrylic acid retanning agent and a preparation method thereof. Background Art

[0002] Emulsion-based acrylic retanning agents are widely used in leather processing, improving the quality and performance of leather. With the development of the leather industry, the requirements for leather retanning agents are becoming increasingly higher. Due to its excellent performance, emulsion-based acrylic retanning agents have gradually become one of the most important types of leather retanning agents.

[0003] Some of these products are made by grafting acrylic acid with natural oils, such as sulfated castor oil, in water through an emulsion copolymerization process. Others are made by emulsion copolymerization of acrylic acid with fatty alcohol (meth)acrylates in the presence of an emulsifier. Still others are made by copolymerizing alkyl polyoxyethylene ether (meth)acrylates with acrylic acid. Products made with alkyl polyoxyethylene ether (meth)acrylate copolymerization offer plumpness, softness, and good filling properties, but are relatively expensive, and currently only imported products are widely used. However, these products suffer from poor stability, making them difficult to use in winter, prone to delamination, and sometimes soft and lacking in filling. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] Therefore, the first object of the present invention is to provide a method for preparing an emulsion-type acrylic retanning agent, which has the advantages of being stable and non-stratified, simple to prepare, and low in cost, and making leathers that are plump, soft, and well-filled.

[0006] To achieve the above object, the first aspect of the present invention provides a method for preparing an emulsion-type acrylic retanning agent, comprising the following steps:

[0007] S1, a nonionic surfactant, reacts with maleic anhydride to obtain an intermediate;

[0008] S2, the intermediate and the vinyl monomer undergo copolymerization reaction under the action of a reaction medium, an emulsifier and an initiator to obtain an emulsion type acrylic acid retanning agent.

[0009] Furthermore, the nonionic surfactant is selected from: fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ether, fatty acid polyoxyethylene ester.

[0010] Furthermore, the polymerization reaction temperature is 80-95° C., the reaction time is 3-5 hours, and the pH is controlled at 3-4.

[0011] Furthermore, the vinyl monomer is selected from one or more of acrylic acid, methacrylic acid, acrylamide and maleic acid; and the mass ratio of the intermediate to the vinyl monomer is 1.0:1.2-3.6.

[0012] Furthermore, the initiator is selected from one or a combination of ammonium persulfate, potassium persulfate and sodium persulfate, and the amount used is 0.5-2.5% of the total mass of the intermediate and monomer; and the reaction medium is water.

[0013] Furthermore, in the nonionic surfactant, the alcohol or acid C number of the saturated / unsaturated fatty alcohol or unsaturated fatty acid is 10 to 22, and the number of polyoxyethylene chain segments is 3 to 10.

[0014] Furthermore, the molar ratio of the nonionic surfactant to maleic anhydride is 1:1.02-1.05.

[0015] Furthermore, the emulsifier is one or a mixture of dodecylbenzenesulfonic acid, dodecylsulfonic acid, sodium lauryl sulfate, and disodium alkyl succinate, and the amount used is 1 to 4.5% of the total mass of the intermediate and monomer.

[0016] Furthermore, the intermediate reaction temperature is 90-115° C., and the reaction time is 2-3 hours.

[0017] Another object of the present invention is to provide an emulsion-type acrylic acid retanning agent obtained by the above-mentioned preparation method.

[0018] Beneficial effects: The present invention obtains an intermediate containing an unsaturated double bond by reacting fatty alcohol (acid) polyoxyethylene ether (ester) with maleic anhydride, and then performs emulsion polymerization with an ethylene monomer in water to obtain a product. The finished product is stable and does not delaminate, is simple to make, and has low cost. The processed leather is plump, soft, and well-filled.

[0019] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention and are not to be construed as limiting the present invention. On the contrary, the embodiments of the present invention include all variations, modifications, and equivalents that fall within the spirit and scope of the appended claims.

[0021] The following describes the emulsion type acrylic acid retanning agent and its preparation method according to the embodiment of the present invention.

[0022] The preparation method of the emulsion type acrylic acid retanning agent of the present invention is achieved by the following steps:

[0023] Step 1: The molar ratio of nonionic surfactant to maleic anhydride is 1:1.05, the reaction temperature is 90-115° C., and the reaction time is 2-3 hours to obtain an intermediate.

[0024] The nonionic surfactant raw material is selected from one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ether, and fatty acid polyoxyethylene ester, wherein the C number of the alcohol or acid is 10 to 22 saturated / unsaturated fatty alcohol or unsaturated fatty acid, and the number of polyoxyethylene chain segments is 3 to 10. The intermediate is reacted with maleic anhydride to obtain an intermediate, which is used to replace expensive commercial alkyl polyoxyethylene ether (meth)acrylate, with low cost and stable finished product without delamination.

[0025] Step 2: The intermediate and the vinyl monomer undergo copolymerization reaction under the action of a reaction medium, an emulsifier, and an initiator to obtain an emulsion type acrylic acid retanning agent. The polymerization reaction temperature is 80-95° C. and the reaction time is 3-5 hours.

[0026] The reaction medium is water, preferably deionized water. The emulsifier is a mixture of one or two of dodecylbenzenesulfonic acid, dodecylsulfonic acid, sodium dodecyl sulfate, and disodium alkyl succinate. The dosage is 1 to 4.5% of the total mass of the intermediate and monomer. The initiator is selected from one or a combination of ammonium persulfate, sodium persulfate, or potassium persulfate. The dosage is 0.5 to 2.5% of the total mass of the intermediate and monomer. The vinyl monomer is selected from one or more of acrylic acid, methacrylic acid, acrylamide, and maleic acid. The mass ratio of the intermediate to the vinyl monomer is 1.0:1.2 to 3.6. If the vinyl monomer is one or more of acrylic acid, methacrylic acid, and maleic acid, it needs to be moderately neutralized with a 30% NaOH solution, and the pH is controlled at 3 to 4.

[0027] In step 2, in the presence of an emulsifier, the intermediate is added once or in portions, the temperature is raised to 80-90° C., and the vinyl monomer and initiator solution are continuously added dropwise. The addition time is 90-120 minutes, and the reaction time is 3-5 hours.

[0028] Example 1

[0029] 32.6 parts of AEO-5 fatty alcohol (acid) polyoxyethylene ether (ester) and 8 parts of maleic anhydride were added to a reactor, stirred, heated, and maintained at 100-110°C for 2.5 hours. After the reaction was complete, 5 parts of sodium dodecylbenzenesulfonate and 290 parts of deionized water were added. 195 parts of acrylic acid were added to 129 parts of deionized water and neutralized with 37.4 parts of a 30% sodium hydroxide solution while stirring. 31.5 parts of a 4% ammonium persulfate solution and a lightly neutralized acrylic acid solution were added dropwise at 80-90°C over 60 minutes. After the additions were complete, the mixture was maintained at room temperature for 2 hours, cooled, and discharged to yield an emulsion-type acrylic retanning agent with a solids content of approximately 33%. The finished product showed no delamination after 12 months of storage, and the leather produced was plump, soft, and well-filled.

[0030] Example 2

[0031] 33.8 parts of AEO-7 fatty alcohol (acid) polyoxyethylene ether (ester) and 6.9 parts of maleic anhydride were added to a reactor, stirred, heated, and maintained at 100-110°C for 2.5 hours. After the reaction was complete, 5 parts of sodium dodecylbenzenesulfonate and 290 parts of deionized water were added. 195 parts of acrylic acid were added to 129 parts of deionized water and neutralized with 37.4 parts of a 30% NaOH solution while stirring. 31.5 parts of a 4% ammonium persulfate solution and a lightly neutralized acrylic acid solution were added dropwise at 80-90°C over 60 minutes. After the additions were complete, the mixture was maintained at this temperature for 2 hours, cooled, and discharged to yield an emulsion-type acrylic retanning agent with a solids content of approximately 33%. The finished product showed no delamination after 12 months of storage, and the leather produced was plump, soft, and well-filled.

[0032] Example 3

[0033] Place 12.8 parts of AEO-3 fatty alcohol (acid) polyoxyethylene ether (ester), 28.4 parts of AEO-7, and 9.85 parts of maleic anhydride in a reactor, stir, heat, and maintain at 100-110°C for 2.5 hours. After the reaction is complete, add 5 parts of sodium dodecylbenzenesulfonate and 290 parts of deionized water. Add 195 parts of acrylic acid to 129 parts of deionized water and, while stirring, neutralize with 37.4 parts of a 30% NaOH solution. Add 31.5 parts of a 4% ammonium persulfate solution and a lightly neutralized acrylic acid solution dropwise at 80-90°C over 60 minutes. After addition, maintain the temperature for 2 hours, cool, and discharge to obtain an emulsion-type acrylic retanning agent with a solids content of approximately 33%. The finished product exhibits no delamination after 12 months of storage. The leather produced is plump, soft, and well-filled.

[0034] Example 4

[0035] 61 parts of polyethylene glycol, 400 parts of oleate, and 9 parts of maleic anhydride were added to a reactor, stirred, heated, and maintained at 100-110°C for 2.5 hours. After the reaction was complete, 5 parts of sodium dodecylbenzenesulfonate and 290 parts of deionized water were added. 150 parts of acrylic acid were added to 106 parts of deionized water and neutralized with 33 parts of a 30% sodium hydroxide solution while stirring. 24 parts of a 14% ammonium persulfate solution and a lightly neutralized acrylic acid solution were added dropwise at 80-90°C over 60 minutes. After addition, the mixture was maintained at this temperature for 2 hours, cooled, and discharged to obtain an emulsion-type acrylic retanning agent with a solids content of approximately 33%. The finished product showed no delamination after storage for 10 months, and the leather produced was plump, soft, and well-filled.

[0036] In summary, the present invention obtains an intermediate containing an unsaturated double bond by reacting fatty alcohol (acid) polyoxyethylene ether (ester) with maleic anhydride, and then performs emulsion polymerization with an ethylene monomer in water to obtain a product. Compared with the products obtained by emulsion copolymerization of acrylic acid and fatty alcohol (meth) acrylate in the presence of an emulsifier; or the products prepared by copolymerization of alkyl polyoxyethylene ether (meth) acrylate and acrylic acid, the cost is lower and the finished product has better stability, is not easy to delaminate, and the processed leather is plump, soft, and well filled.

[0037] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and deform the above embodiments within the scope of the present invention.

Claims

1. A method for preparing an emulsion-type acrylic acid retanning agent, characterized in that: The following steps are involved: S1, a nonionic surfactant, reacts with maleic anhydride to obtain an intermediate; S2, the intermediate and the vinyl monomer undergo copolymerization reaction under the action of a reaction medium, an emulsifier, and an initiator to obtain an emulsion type acrylic retanning agent; The nonionic surfactant is selected from: one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ether, and fatty acid polyoxyethylene ester; The vinyl monomer is selected from one or more of acrylic acid, methacrylic acid, acrylamide and maleic acid; the mass ratio of the intermediate to the vinyl monomer is 1.0:1.2-3.6; In the nonionic surfactant, the alcohol or acid is a saturated / unsaturated fatty alcohol or unsaturated fatty acid with a carbon number of 10 to 22, and the number of polyoxyethylene chain segments is 3 to 10; The molar ratio of the nonionic surfactant to maleic anhydride is 1:1.02-1.

05.

2. The method for preparing an emulsion-type acrylic acid retanning agent according to claim 1, wherein The polymerization reaction temperature is 80-95° C., the reaction time is 3-5 hours, and the pH is controlled at 3-4.

3. The preparation method of the emulsion type acrylic acid retanning agent according to claim 1, characterized in that, The initiator is selected from one or a combination of ammonium persulfate, potassium persulfate and sodium persulfate, and the amount used is 0.5-2.5% of the total mass of the intermediate and monomer; the reaction medium is water.

4. The method for preparing an emulsion-type acrylic acid retanning agent according to claim 1, wherein The emulsifier is one or a mixture of dodecylbenzenesulfonic acid, dodecylsulfonic acid, sodium lauryl sulfate, and disodium alkyl succinate, and the amount used is 1-4.5% of the total mass of the intermediate and the monomer.

5. The method for preparing an emulsion-type acrylic acid retanning agent according to claim 1, wherein: The intermediate reaction temperature is 90-115° C., and the reaction time is 2-3 hours.

6. An emulsion type acrylic acid retanning agent, characterized in that The emulsion-type acrylic retanning agent is obtained by the preparation method of any one of claims 1 to 5.