Isocyanate modified acrylate polymer fatliquor and preparation method thereof

Abstract

The invention relates to the technical field of leather chemicals, and discloses an isocyanate modified acrylate polymer fatting agent and a preparation method thereof, and the preparation method comprises the following steps: (1) adding acetoacetoxy methacrylic acid gylcol ester, octadecyl isocyanate and a catalyst into a reaction system, and carrying out reaction treatment; (2) adding a solvent, formaldehyde and N-methyl taurine into a reaction system in the step (1), and carrying out heating reaction; and (3) dropwise adding azodiisobutyronitrile and dodecanethiol into the solution obtained in the step (2) to carry out solution polymerization, after dropwise adding, carrying out heat preservation, and then adding tara gum to obtain a finished product. The polymer fatliquoring agent provided by the invention can more easily permeate into skin collagen, so that the fatliquoring performance is improved, and the polymer fatliquoring agent also has excellent stability and low temperature resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of leather chemicals, in particular to an isocyanate-modified acrylic polymer fatliquor and a preparation method thereof. Background Art

[0002] Polymer fatliquor molecules contain both hydrophilic groups and long-chain hydrophobic groups. The hydrophilic groups impart good permeability and collagen-binding properties to the fatliquor. The long-chain hydrophobic groups disperse and lubricate fibers, making the leather soft and resistant to folding, thus resolving the problem of stiff finished leather.

[0003] There have been reports on the use of long-chain acrylates as polymerization monomers and the use of emulsion polymerization to prepare waterproof fatliquors. For example, Yu Desheng et al. used cyclodextrin as a solubilizing carrier and ammonium persulfate as an initiator to achieve a ternary copolymerization of octadecyl acrylate, lauryl acrylate, and acrylic acid. The leather treated with this ternary copolymer had good waterproofness, softness, and thickening rate (Yu Desheng, Du Jinxia, Tan Ran, et al. Preparation of ternary emulsion copolymerization of acrylate amphiphilic polymers and their retanning and fatliquor properties [J]. Leather Science and Engineering, 2020, 30(3):7). In this technology, the polymerization process only uses carboxylates to give the polymer hydrophilic groups. The polymer itself is not hydrophilic enough. By adding emulsifiers to reduce the particle size of the latex particles, the polymer has weak permeability in the leather fiber. Patent CN102199244A discloses a preparation method of a phosphate leather retanning fatting agent, first maleic anhydride, styrene and octadecyl acrylate are copolymerized, then polyethylene glycol is introduced on the polymer chain, then modified with a phosphorylating agent to prepare a retanning fatting agent containing phosphate group, carboxyl group and long-chain alkyl group simultaneously. In this technology, phosphate ester and carboxylate are used to provide polymer hydrophilicity, but hydrophilicity is insufficient. Therefore, it is necessary to introduce a large amount of nonionic ethoxy groups to improve hydrophilicity. Patent CN104195273A discloses a phospholipid fatting retanning agent and a preparation method thereof, in the acrylic ester polymer prepared, a sulfonic acid group containing a double bond is introduced as a comonomer, because the functional groups connected near the double bond are different, the reactivity of the double bond is caused to differ, so that the reactivity ratio is different, and the monomer participation in the polymerization reaction is incomplete. Summary of the Invention

[0004] The present invention provides an isocyanate-modified acrylate polymer fatliquor and a preparation method thereof, so as to solve the problem in the prior art that long carbon chain acrylate derivatives need to be copolymerized with other acrylates and the polymerization efficiency is low.

[0005] Specifically:

[0006] First, the present invention provides a method for preparing an isocyanate-modified acrylic polymer fatliquor, comprising the following steps (synthetic route as shown in FIG.Figure 1 shown):

[0007] (1) adding ethylene glycol acetoacetate methacrylate AAEM, octadecyl isocyanate ODI, and a catalyst into the reaction system and performing reaction treatment;

[0008] (2) adding solvent N,N-dimethylacetamide, formaldehyde, and N-methyltaurine to the reaction system in (1) and reacting by heating;

[0009] (3) AIBN and dodecanethiol are added dropwise to (2) to carry out solution polymerization. After the addition is completed, the mixture is kept warm and tara gum is added to obtain the finished product.

[0010] According to some preferred embodiments, in (1), the catalyst is acrylic acid AA.

[0011] According to some preferred embodiments, in (1), the system temperature is controlled to be 50-55° C., and the reaction is kept warm until the isocyanate group disappears.

[0012] According to some preferred embodiments, in (2), the temperature is raised to 70-75° C. for 2-3 hours.

[0013] According to some preferred embodiments, in (3), the heat preservation is: 70-75°C, 0.5-1.5h.

[0014] According to some preferred embodiments, in (3), tara gum accounts for 3-5% of the mass of the finished product.

[0015] According to some preferred embodiments, the molar ratio of octadecyl isocyanate, ethylene glycol acetoacetoxymethacrylate, catalyst, formaldehyde, and N-methyltaurine is 1:2.0-2.5:1:0.7-1.2:0.7-1.2.

[0016] According to some preferred embodiments, the amount of octadecyl isocyanate, ethylene glycol acetoacetate, catalyst, formaldehyde, and N-methyltaurine is used as the total amount, the amount of azobisisobutyronitrile accounts for 3% to 6% of the total amount; the amount of dodecanethiol accounts for 2% to 5% of the total amount; and the amount of solvent accounts for 0.97 to 1.35 times the total amount.

[0017] According to some preferred embodiments, the molar concentration of azobisisobutyronitrile is 1.01 mmol / mL to 1.54 mmol / mL, and the solvent is N,N-dimethylacetamide.

[0018] According to some preferred embodiments, the molar concentration of dodecanethiol is 1.86 mmol / mL to 2.50 mmol / mL, and the solvent is N,N-dimethylacetamide.

[0019] Second, the present invention provides an isocyanate-modified acrylic polymer fatliquor obtained by the aforementioned preparation method.

[0020] The beneficial effects achieved by the present invention are:

[0021] (1) The preparation method provided by the present invention provides a sulfonic acid group-containing intermediate prepared by the method, which is synthesized using the same raw materials, has the same reactivity, and is more easily polymerized to form a similar homopolymer. If 2-acrylamide-2-methylpropanesulfonic acid is used as the hydrophilic monomer (the comparative example described below) with the same molar amount of sulfonic acid group-containing monomer, the polymerization efficiency is low due to the difference in reactivity ratio, resulting in a milky white liquid. However, the liquid prepared by the present invention using the hydrophilic monomer is transparent.

[0022] (2) The preparation method provided by the present invention utilizes a long carbon chain isocyanate to react with the intermediate A to prepare the intermediate A containing both a double bond and a long carbon chain, thereby imparting fatliquoring properties to the leather;

[0023] (3) The preparation method provided by the present invention utilizes the principle of Mannich reaction, uses formaldehyde and N-methyltaurine to react with ethylene glycol acetoacetate to prepare an intermediate B containing both a double bond and a sulfonic acid group; the use of the intermediate B improves the hydrophilicity of the fatliquor, making it easier to penetrate into the interior of the skin collagen fibers, thereby improving the fatliquor performance;

[0024] (4) The preparation method provided by the present invention, wherein ethylene glycol acetoacetate methacrylate is used as an intermediate to prepare the raw material, and an excess of ethylene glycol acetoacetate methacrylate participates in the copolymerization, thereby improving the utilization rate of the raw material; the active hydrogen contained therein increases the binding property of the fatliquor with the skin collagen;

[0025] (5) The preparation method provided by the present invention comprises solution polymerization of intermediate A, intermediate B, acrylic acid and an excess of ethylene glycol acetoacetate to prepare a polymer fatliquor with fatliquor properties;

[0026] (6) The preparation method provided by the present invention uses acrylic acid as a catalyst to prepare intermediate A and also uses it as a comonomer during the preparation process; the carboxyl groups contained in acrylic acid complex with chromium during the fatliquoring process of chrome-tanned leather, thereby improving the binding property;

[0027] (7) The isocyanate-modified acrylic polymer fatliquor prepared by the present invention contains abundant ketone carbonyl groups, ester groups and amide bonds, and can be well compounded with the polysaccharide in tara gum, thereby improving the low-temperature resistance; and tara gum further improves the stability of the fatliquor, thereby increasing the filling property and smooth feel of the leather after fatliquor.

[0028] (8) The isocyanate-modified acrylic polymer fatliquor prepared by the present invention contains functional groups such as amino groups and amide bonds. The fatliquored leather has a high absorption rate for dyes and can prevent color fading. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the synthesis route of the acrylic polymer fatliquor provided by the present invention;

[0030] Figure 2 These are product appearance pictures of the fatliquors obtained in Comparative Example 1 and Example 1. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0032] Example 1

[0033] This embodiment provides a method for preparing an isocyanate-modified acrylic polymer fatliquor, comprising the following steps:

[0034] (1) Add 118.20 g (0.4000 mol) of ODI, 171.38 g (0.8000 mol) of AAEM, and 28.82 g (0.4000 mol) of AA into a reaction vessel, control the temperature at 50°C, and keep the temperature to react until the isocyanate group disappears.

[0035] (2) Add 355 mL of DMAc, 22.73 g of 37% (0.2800 mol) formaldehyde solution, and 38.97 g (0.2800 mol) of N-methyltaurine to step (1). Stirring was started and the temperature was kept at 70°C for 3 h.

[0036] (3) After the reaction was complete, 66 mL of a 1.01 mmol / mL AIBN solution in DMAc and 19 mL of a 1.86 mmol / mL dodecanethiol solution in DMAc were added dropwise to carry out solution polymerization. The addition time was controlled within 3 h. After the addition was complete, the mixture was kept at 70°C for 1 h. Then, 10.97 g of tara gum and 315.49 g of deionized water were added and stirred to form a 30% solids solution.

[0037] Example 2

[0038] This embodiment provides a method for preparing an isocyanate-modified acrylic polymer fatliquor, comprising the following steps:

[0039] (1) Add 118.20 g (0.4000 mol) of ODI, 197.08 g (0.9200 mol) of AAEM, and 28.82 g (0.4000 mol) of AA into a reaction vessel, control the temperature at 52°C, and keep the temperature to react until the isocyanate group disappears.

[0040] (2) Add 494 mL of DMAc, 32.46 g of 37% (0.4000 mol) formaldehyde solution, and 55.67 g (0.4000 mol) of N-methyltaurine to step (1). Stirring was started and the temperature was kept at 73°C for 2.5 h.

[0041] (3) After the reaction was complete, 120 mL of a 1.25 mmol / mL AIBN solution in DMAc and 51 mL of a 2.00 mmol / mL dodecanethiol solution in DMAc were added dropwise to carry out solution polymerization. The addition time was controlled within 3.5 h. After the addition was complete, the mixture was kept at 73°C for 1 h. 16.47 g of tara gum and 143.36 g of deionized water were added and stirred to form a 30% solids solution.

[0042] Example 3

[0043] This embodiment provides a method for preparing an isocyanate-modified acrylic polymer fatliquor, comprising the following steps:

[0044] (1) Add 118.20 g (0.4000 mol) of ODI, 214.22 g (1.0000 mol) of AAEM, and 28.82 g (0.4000 mol) of AA into a reaction vessel, control the temperature at 52°C, and keep the temperature to react until the isocyanate group disappears.

[0045] (2) Add 597 mL of DMAc to step (1), add 38.96 g of 37% (0.4800 mol) formaldehyde solution and 66.80 g (0.4800 mol) of N-methyltaurine. Stirring is started, and the temperature is maintained at 75°C for 2 h.

[0046] (3) After the reaction was complete, 105 mL of a 1.54 mmol / mL DMAc solution of AIBN and 44 mL of a 2.50 mmol / mL DMAc solution of dodecanethiol were added dropwise to carry out solution polymerization. The addition time was controlled within 4 h. After the addition was complete, the mixture was kept at 75°C for 1 h. 22.12 g of tara gum and 230.24 g of deionized water were added and stirred to form a 30% solids solution.

[0047] Comparative Example 1

[0048] This comparative example provides a method for preparing an isocyanate-modified acrylic polymer fatliquor, comprising the following steps:

[0049] (1) Add 118.20 g (0.4000 mol) of ODI, 171.38 g (0.8000 mol) of AAEM, and 28.82 g (0.4000 mol) of AA into a reaction vessel, control the temperature at 50°C, and keep the temperature to react until the isocyanate group disappears.

[0050] (2) 308 mL of DMAc and 58.03 g (0.7000 mol) of 2-acrylamide-2-methylpropanesulfonic acid were added to step (1), and the temperature was controlled at 70° C. Simultaneously, 58 mL of a DMAc solution having a molar concentration of 1.01 mmol / mL of ABN and 17 mL of a DMAc solution having a molar concentration of 1.86 mmol / mL of dodecanethiol were added dropwise to carry out solution polymerization. The addition time was controlled to be 3 h. After the addition was complete, the mixture was kept at 70° C. for 1 h. 9.55 g of tara gum and 274.63 g of deionized water were added, and the mixture was stirred and uniformly prepared into a 30% solids solution.

[0051] Comparative Example 2

[0052] This comparative example provides a method for preparing an isocyanate-modified acrylic polymer fatliquor, comprising the following steps:

[0053] (1) Add 118.20 g (0.4000 mol) of ODI, 197.08 g (0.9200 mol) of AAEM, and 28.82 g (0.4000 mol) of AA into a reaction vessel, control the temperature at 52°C, and keep the temperature to react until the isocyanate group disappears.

[0054] (2) 413 mL of DMAc and 58.03 g (0.7000 mol) of 2-acrylamide-2-methylpropanesulfonic acid were added to the reaction mixture in step (1). The temperature was controlled at 73° C., and 101 mL of a 1.25 mmol / mL DMAc solution of AIBN and 43 mL of a 2.00 mmol / mL dodecanethiol DMAc solution were added dropwise to carry out solution polymerization. The addition time was controlled to be 3.5 h. After the addition was complete, the mixture was kept at 73° C. for 1 h. 13.76 g of tara gum and 119.80 g of deionized water were added, and the mixture was stirred and uniformly mixed to form a 30% solids solution.

[0055] Comparative Example 3

[0056] This comparative example provides a method for preparing an isocyanate-modified acrylic polymer fatliquor, comprising the following steps:

[0057] (1) Add 118.20 g (0.4000 mol) of ODI, 214.22 g (1.0000 mol) of AAEM, and 28.82 g (0.4000 mol) of AA into a reaction vessel, control the temperature at 52°C, and keep the temperature to react until the isocyanate group disappears.

[0058] (2) 488 mL of DMAc and 58.03 g (0.7000 mol) of 2-acrylamide-2-methylpropanesulfonic acid were added to step (1), and the temperature was controlled at 75° C. At the same time, 86 mL of a DMAc solution having a molar concentration of 1.54 mmol / mL AIBN and 36 mL of a DMAc solution having a molar concentration of 2.50 mmol / mL dodecanethiol were added dropwise to carry out solution polymerization. The addition time was controlled to be 4 h. After the addition was complete, the mixture was kept at 75° C. for 1 h. 18.06 g of tara gum and 187.98 g of deionized water were added, and the mixture was stirred and uniformly prepared into a 30% solids solution.

[0059] Test example

[0060] Performance tests were performed using Examples 1-3 and Comparative Examples 1-3 as samples.

[0061] Test Example 1 - Determination of water solubility, acid resistance, and wastewater COD content

[0062] The specific detection method is as follows:

[0063] Water solubility of the product: At room temperature, use deionized water to prepare a 10% by mass aqueous solution of the product, and observe the difficulty of dissolution of the product and the state of the solution.

[0064] Acid resistance: Prepare a 10% product aqueous solution with deionized water, adjust the pH to 2.5 with 10% sulfuric acid, let it stand for 24 hours, and observe whether there is precipitation or floating matter.

[0065] Wastewater COD content: tested in accordance with standard GB 11914-1989.

[0066] Product stability: Place 40g of product in a centrifuge tube at 3500 rpm for 30 minutes. Remove the product and observe whether it separates. If it does not separate, it can be stored at room temperature for at least 6 months.

[0067] The product appearance of Example 1 and Comparative Example 1 is as follows Figure 2 shown.

[0068] The measurement results are shown in Table 1.

[0069] Table 1 Performance test results of polymer fatliquor

[0070]

[0071] Test Example 2 - Application test for chrome tanned leather

[0072] Examples 1-3 were used to fatliquore and dye self-purchased yellow cattle wet blue leather, i.e., to fatliquore chrome-tanned leather. The operating procedures are shown in Table 2 below, and the application results are shown in Table 3. In Table 2, the yellow cattle wet blue leather was from Zhejiang Tongtianxing Group Co., Ltd., direct black VSF600 was purchased from Shenzhen Longgang District Jincaiyuan Chemical Dye Trading Co., Ltd., the degreasing agent DOC, interstitial remover TJ-A180, rewetting protectant BSP, spot remover TJ-A971, chrome tanning agent TJ-T125, and high-efficiency neutralizer TJ-R819 were all from Sichuan Tingjiang New Materials Co., Ltd., and other chemicals were from Kelon Reagent Co., Ltd. All chemical amounts were calculated as percentages by weight of the wet blue leather.

[0073] Table 2 Products used in chrome tanned leather application process

[0074]

[0075]

[0076] Table 3 Application results of products in chrome tanned leather

[0077]

[0078]

[0079] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing an isocyanate-modified acrylic polymer fatliquor, characterized in that: The steps include: (1) adding ethylene glycol acetoacetate methacrylate, octadecyl isocyanate, and a catalyst into the reaction system and subjecting the reaction system to reaction treatment; (2) adding a solvent, formaldehyde, and N-methyltaurine to the reaction system in (1) and reacting by heating; (3) Azobisisobutyronitrile and dodecanethiol are added dropwise to (2) to carry out solution polymerization. After the addition is completed, the mixture is kept warm and tara gum is added to obtain the finished product.

2. The method for preparing the isocyanate-modified acrylic polymer fatliquor according to claim 1, wherein In (1), the catalyst is acrylic acid.

3. The method for preparing the isocyanate-modified acrylic polymer fatliquor according to claim 1, wherein: In (1), the system temperature is controlled at 50-55°C and the reaction is carried out at this temperature until the isocyanate groups disappear.

4. The method for preparing the isocyanate-modified acrylic polymer fatliquor according to claim 1, wherein: (2) Heat the reaction to 70-75°C for 2-3 hours.

5. The method for preparing the isocyanate-modified acrylic polymer fatliquor according to claim 1, wherein: (3) Medium, heat preservation: 70-75℃, 0.5-1.5h.

6. The method for preparing the isocyanate-modified acrylic polymer fatliquor according to any one of claims 1 to 5, characterized in that: The molar ratio of octadecyl isocyanate, ethylene glycol acetoacetate methacrylate, catalyst, formaldehyde and N-methyltaurine is 1:2.0-2.5:1:0.7-1.2:0.7-1.

2.

7. The method for preparing the isocyanate-modified acrylic polymer fatliquor according to claim 6, wherein: The amount of octadecyl isocyanate, ethylene glycol acetoacetate methacrylate, catalyst, formaldehyde and N-methyltaurine is taken as the total amount, and the amount of azobisisobutyronitrile accounts for 3% to 6% of the total amount.

8. The method for preparing the isocyanate-modified acrylic polymer fatliquor according to claim 6, wherein: The total amount of octadecyl isocyanate, ethylene glycol acetoacetate methacrylate, catalyst, formaldehyde and N-methyltaurine is taken as the total amount, and the amount of dodecyl mercaptan accounts for 2% to 5% of the total amount.

9. The method for preparing the isocyanate-modified acrylic polymer fatliquor according to claim 6, wherein: The amount of the solvent used is 0.97 to 1.35 times the total amount of octadecyl isocyanate, ethylene glycol acetoacetate methacrylate, catalyst, formaldehyde and N-methyltaurine.

10. An acrylic acid ester polymer fatliquor obtained by the preparation method according to any one of claims 1 to 9.

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