Acrylate polymer leather waterproof coating agent and preparation method thereof

Abstract

The invention relates to the technical field of leather finishing agents, and discloses an acrylate polymer leather waterproof finishing 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 deionized water and an emulsifier into the reaction system in the step (1), and emulsifying to obtain an emulsion; (3) taking part of the emulsion in the step (2), dropwise adding an initiator, then adding the rest emulsion, and carrying out heat preservation treatment; and (4) adding adipic acid dihydrazide into the product obtained in the step (3), and reacting to obtain a finished product. The finishing agent provided by the invention has the advantages of good permeability, good wear resistance, good bonding strength with leather, and no pollution in the preparation method.

Description

Technical Field

[0001] The invention relates to the technical field of leather finishing agents, in particular to an acrylate polymer leather waterproof finishing agent and a preparation method thereof. Background Art

[0002] Currently, leather waterproofing agents are mostly leather fatliquors. Reports of leather finishes with waterproofing properties primarily rely on the introduction of fluorinated compounds as functional monomers to impart waterproofing properties. However, fluorinated polymer solutions typically have a high viscosity, making it difficult for them to penetrate the surface layer of leather when applied. Insufficient penetration results in preferential contact between the coating and the leather substrate, leading to weak adhesion. Summary of the Invention

[0003] The present invention provides an acrylic polymer leather waterproof finishing agent and a preparation method thereof, so as to solve the shortcomings of poor permeability and weak bonding force of leather finishing agents in the prior art.

[0004] Specifically:

[0005] First, the present invention provides a method for preparing an acrylic polymer leather waterproof finishing agent, comprising the following steps (synthetic route as shown in FIG. Figure 1 shown):

[0006] (1) adding ethylene glycol acetoacetate methacrylate AAEM, octadecyl isocyanate ODI, and a catalyst into the reaction system and performing reaction treatment;

[0007] (2) adding deionized water and an emulsifier to the reaction system in (1) and performing emulsification treatment to obtain an emulsion;

[0008] (3) taking part of the emulsion in (2), adding an initiator dropwise, and then adding the remaining emulsion, and then heat-insulating;

[0009] (4) Add adipic acid dihydrazide to (3) and react 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 emulsifier includes at least one of AES-370 and AEO-9.

[0013] According to some preferred embodiments, in (3), the initiator includes at least one of ammonium persulfate and sodium persulfate, and the concentration of the initiator is 0.5 mol / L to 0.9 mol / L.

[0014] According to some preferred embodiments, in (3), the temperature is kept at 65-70° C. for 0.5-2 h.

[0015] According to some preferred embodiments, in (4), the pH value of the reaction system is adjusted to 7.0-7.5.

[0016] According to some preferred embodiments, the molar ratio of ethylene glycol acetoacetoxy methacrylate, octadecyl isocyanate, and the catalyst is 1:1.5-2.0:0.6-0.8.

[0017] According to some preferred embodiments, the amount of ethylene glycol acetoacetoxy methacrylate, octadecyl isocyanate, and the catalyst is used as the total amount, and the amount of adipic acid dihydrazide accounts for 2% to 3% of the total amount.

[0018] According to some preferred embodiments, the amount of the initiator is 1% to 1.5% of the total amount of ethylene glycol acetoacetate, octadecyl isocyanate and the catalyst.

[0019] According to some preferred embodiments, the amount of the emulsifier is 1% to 2% of the total amount, taking the amount of ethylene glycol acetoacetoxy methacrylate, octadecyl isocyanate, and the catalyst as the total amount.

[0020] Second, the present invention provides an acrylic polymer leather waterproof finishing agent obtained by the aforementioned preparation method.

[0021] The beneficial effects achieved by the present invention are:

[0022] (1) The preparation method provided by the present invention adopts an emulsion polymerization method and can improve the wetting properties of the emulsion by adding an emulsifier, thereby enhancing the penetration ability of the finishing agent;

[0023] (2) The preparation method provided by the present invention involves copolymerization by adding an excess of ethylene glycol acetoacetate, wherein the active hydrogen can form a covalent bond with the amino group in the skin collagen fiber, thereby improving the binding performance;

[0024] (3) The preparation method provided by the present invention improves the friction resistance of the finishing agent by introducing isocyanate groups to participate in the reaction;

[0025] (4) The preparation method provided by the present invention uses adipic acid dihydrazide as a crosslinking agent to form a ketone hydrazide crosslinking with the carbonyl group of acetoacetoxy ethylene glycol methacrylate, thereby overcoming the disadvantage of the acrylic ester polymer film being sticky when hot and brittle when cold;

[0026] (5) The present invention provides a preparation method in which no organic solvent is used in the preparation process, which pollutes the environment;

[0027] (6) The present invention introduces carboxyl groups into the finishing agent, thereby improving the bonding strength between the finishing agent and the leather. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the synthesis route of the waterproof coating agent provided by the present invention. DETAILED DESCRIPTION

[0029] 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.

[0030] Example 1

[0031] This embodiment provides a method for preparing an acrylic polymer leather waterproof finishing agent, comprising the following steps:

[0032] (1) Add 1004.70 g (3.40 mol) of ODI, 1092.52 g (5.10 mol) of AAEM, and 147.00 g (2.04 mol) of AA into a reaction vessel, control the temperature at 50°C, and keep the temperature to react until the isocyanate group disappears.

[0033] (2) Add 1818.70g of deionized water and 22.44g of AES-370 to step (1), mix and homogenize using a homogenizer for 1h. Place 440.60g of the emulsion in a four-necked flask, add 320.60g of a 0.5mol / L aqueous solution of ammonium persulfate at 65°C, and continue to add the remaining emulsion while stirring using a peristaltic pump. The addition time is controlled to 3.5h, and after the addition is completed, keep warm at 65°C for 1h. After the reaction is completed, add 62.19g of adipic acid dihydrazide to the solution and adjust the pH to 7.0-7.5 using liquid alkali NaOH.

[0034] Example 2

[0035] This embodiment provides a method for preparing an acrylic polymer leather waterproof finishing agent, comprising the following steps:

[0036] (1) Add 1004.70 g (3.40 mol) of ODI, 1274.61 g (5.95 mol) of AAEM, and 171.50 g (2.38 mol) of AA into a reaction vessel, control the temperature at 53°C, and keep the temperature to react until the isocyanate group disappears.

[0037] (2) Add 2011.23g of deionized water, 18.38g of AES-370, and 18.38g of AEO-9 to step (1), mix, and homogenize and emulsify using a homogenizer for 1 hour. Place 479.29g of the emulsion in a four-necked flask, and add 294.10g of a 0.7mol / L sodium persulfate aqueous solution dropwise at 68°C until the emulsion turns light blue. Continue to add the remaining emulsion dropwise using a peristaltic pump while stirring. The addition time is controlled to 3h, and after the addition is completed, keep warm at 68°C for 1h. After the reaction is completed, add 51.82g of adipic acid dihydrazide to the solution, and adjust the pH to 7.0-7.5 using liquid alkali NaOH.

[0038] Example 3

[0039] This embodiment provides a method for preparing an acrylic polymer leather waterproof finishing agent, comprising the following steps:

[0040] (1) Add 1004.70 g (3.40 mol) of ODI, 1092.52 g (6.80 mol) of AAEM, and 196.00 g (2.72 mol) of AA into a reaction vessel, control the temperature at 55°C, and keep the temperature to react until the isocyanate group disappears.

[0041] (2) Add 2201.83g of deionized water and 53.15g of AEO-9 to step (1), mix and homogenize using a homogenizer for 1 hour. Place 521.90g of the emulsion in a four-necked flask, add 306.62g of 0.9mol / L persulfate aqueous solution dropwise at 70°C until the emulsion turns light blue, and continue to add the remaining emulsion dropwise using a peristaltic pump while stirring. The addition time is controlled within 4 hours, and after the addition is completed, keep warm at 70°C for 1 hour. After the reaction is completed, add 77.00g of adipic acid dihydrazide to the solution and adjust the pH to 7.0-7.5 using liquid alkali NaOH.

[0042] Comparative Example

[0043] Add 1151.14g (3.40mol) of octadecyl methacrylate, 546.26g (2.55mol) of AAEM and 171.50g (2.38mol) of AA to the reaction vessel, add 1533.69g of deionized water, 14.02g of AES-370 and 14.02g of AEO-9, mix and homogenize using a homogenizer for 1h. Place 365.49g of the emulsion in a four-necked flask and add 224.27g of a 0.7mol / L sodium persulfate aqueous solution dropwise at 68°C until the emulsion turns light blue. Continue to add the remaining emulsion dropwise using a peristaltic pump while stirring. The addition time is controlled within 3h. After the addition is complete, keep warm at 68°C for 1h. Use liquid alkali NaOH to adjust the pH to 7.0-7.5.

[0044] Test example

[0045] The performance of the leather finishing agents prepared in Examples 1-3 and the comparative example was tested, and the results are shown in Table 1.

[0046] The leather finishing agents of Examples 1-3 and the comparative example were used, and the leather used was chrome-tanned yellow cowhide. The finishing agent was applied to the wet leather surface using a roller coating method. The roller coating was repeated twice, with the first application amount being 9-10 g / sf and the second application amount being 6-7 g / sf. After coating, the leather was oven-dried at 100-120°C for 1-10 minutes to form a crosslinked film.

[0047] The contact angle of liquid droplets and the abrasion resistance (dry and wet rubbing) of the coated leather were measured and shown in Table 2.

[0048] Water drop contact angle measurement: After the painted leather is dried, the water drop contact angle is measured using a contact angle meter.

[0049] Determination of dry and wet rubbing resistance: Add 10% water-based black paste to the finishing agent and apply it to the leather surface with a roller. Then determine the color fastness to rubbing according to the method specified in GB / T3920-2008 "Textiles - Tests for color fastness - Color fastness to rubbing".

[0050]

[0051] Table 2 Application performance test results

[0052] Test items Example 1 Example 2 Example 3 Comparative Example Droplet contact angle 111° 112° 115° 102° Dry Erase Grade Level 5 Level 5 Level 5 4.5 Wet wipe grade Level 5 Level 5 Level 5 Level 4

[0053] From the results in Table 2, we can see that:

[0054] (1) After the finishing agent prepared in this embodiment was applied to leather, the contact angle of the droplet was measured to be significantly greater than that of the comparative example, indicating that the waterproof performance was better than that of the comparative example.

[0055] (2) The wet rubbing grade of this embodiment is better than that of the comparative example, indicating that the use of isocyanate and increased cross-linking can improve the friction resistance of the coating.

Claims

1. A method for preparing an acrylic polymer leather waterproof finishing agent, 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 deionized water and an emulsifier to the reaction system in (1) and performing emulsification treatment to obtain an emulsion; (3) taking part of the emulsion in (2), adding an initiator dropwise, and then adding the remaining emulsion, and then heat-insulating; (4) Add adipic acid dihydrazide to (3) and react to obtain the finished product.

2. The method for preparing the acrylic polymer leather waterproof finishing agent according to claim 1, wherein The catalyst is acrylic acid.

3. The method for preparing the acrylic polymer leather waterproof finishing agent 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 acrylic polymer leather waterproof finishing agent according to claim 1, wherein: In (2), the emulsifier includes at least one of AES-370 and AEO-9.

5. The method for preparing the acrylic polymer leather waterproof finishing agent according to claim 1, wherein: In (3), the initiator includes at least one of ammonium persulfate and sodium persulfate, and the concentration of the initiator is 0.5 mol / L to 0.9 mol / L, and / or, in (3), the temperature is kept at 65 to 70° C. for 0.5 to 2 h.

6. The method for preparing the acrylic polymer leather waterproof finishing agent according to claim 1, characterized in that: (4) The pH value of the reaction system is adjusted to 7.0-7.

5.

7. The method for preparing the acrylic polymer leather waterproof finishing agent according to any one of claims 1 to 6, characterized in that: The molar ratio of ethylene glycol acetoacetate methacrylate, octadecyl isocyanate and catalyst is 1:1.5-2.0:0.6-0.

8.

8. The method for preparing the acrylic polymer leather waterproof finishing agent according to claim 7, characterized in that: The amount of ethylene glycol acetoacetate methacrylate, octadecyl isocyanate and the catalyst is taken as the total amount, and the amount of adipic acid dihydrazide accounts for 2% to 3% of the total amount.

9. The method for preparing the acrylic polymer leather waterproof finishing agent according to claim 8 is characterized in that: Based on the total amount of ethylene glycol acetoacetoxy methacrylate, octadecyl isocyanate and catalyst, the amount of initiator used is 1% to 1.5% of the total amount; and / or, based on the total amount of ethylene glycol acetoacetoxy methacrylate, octadecyl isocyanate and catalyst used, the amount of emulsifier used is 1% to 2% of the total amount.

10. An acrylate polymer leather waterproof finishing agent obtained by the preparation method according to any one of claims 1 to 9.

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