Amphoteric leather fatliquoring agent and method for its preparation

Abstract

The application belongs to the field of leather auxiliaries, and particularly relates to an amphoteric leather fatliquor and a preparation method thereof. The amphoteric leather fatliquor is shown as formula I. The amphoteric leather fatliquor has polar groups such as sulfonic acid groups and secondary amino groups in the structure, and has affinity with polar groups of leather fibers. Non-polar groups can wrap leather fibers, increase the distance between the leather fibers, improve the relative sliding performance of the leather fibers, reduce the friction between the leather fibers, and thus endow the finished leather with excellent softness.

Description

Technical Field

[0001] This invention belongs to the field of leather auxiliaries, specifically relating to an amphoteric leather fatliquoring agent and its preparation method. Background Technology

[0002] Fatliquoring agents can be classified into anionic fatliquoring agents, cationic fatliquoring agents, amphoteric fatliquoring agents, and nonionic fatliquoring agents.

[0003] Currently, the synthesis methods of amphoteric fatliquoring agents mainly involve compounding amphoteric surfactants with raw oil or directly modifying raw oil in an amphoteric manner. The former mainly uses fatty amines as raw materials, but fatty amines are expensive, which is not conducive to large-scale promotion. The latter's amphoteric modification is mainly achieved through quaternization, but the quaternized derivatives are highly cationic and cannot be used in the same bath as anionic dyes. They are mostly added in the later stage of fatliquoring to fix the color, which to some extent limits their application range.

[0004] Therefore, based on this, the technical solution of the present invention is proposed. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a variegated leather fatliquoring agent, as shown in Formula I:

[0006]

[0007] Where n = 10 to 20.

[0008] Preferably, n = 10, 12, 13, 14, 16, 18 or 20.

[0009] Based on the same technical concept, another aspect of the present invention is to provide a method for preparing a fatliquoring agent for amphoteric leather, the method comprising the following steps:

[0010] (1) Mix long-chain fatty alcohols, maleic anhydride and catalyst to react;

[0011] (2) When the acid value of the reaction system reaches 180-200, diethanolamine and catalyst are added to continue the reaction;

[0012] (3) When the acid value of the reaction system reaches 0 to 10, sodium metabisulfite or sodium sulfite, phase transfer agent and water are added to continue the reaction. After the reaction is completed, the amphoteric leather fatliquoring agent is obtained.

[0013] The reaction principle of the preparation method is as follows:

[0014]

[0015] Preferably, in step (1), the long-chain fatty alcohol is one of deca-ol, dodeca-ol, isotridecyl alcohol, tetradecyl alcohol, 12,14-ol, 16,18-ol, and eicosyl alcohol;

[0016] And / or, the catalyst is anhydrous sodium acetate.

[0017] Preferably, in step (1), the reaction temperature is 90–100°C.

[0018] Preferably, in step (2), the catalyst is phosphorous acid;

[0019] And / or, the temperature of the reaction is 190–200°C.

[0020] Preferably, in step (3), the phase transfer agent is ethylene glycol;

[0021] And / or, the reaction temperature is 80–90°C, and the reaction time is 4–5 h.

[0022] Preferably, by weight, the long-chain fatty alcohol is 400 parts, maleic anhydride is 400 parts, diethanolamine is 200 parts, and sodium metabisulfite is 200 parts.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. The amphoteric leather fatliquoring agent of the present invention has polar groups such as sulfonic acid group and secondary amino group in its structure, which are compatible with the polar groups of leather fibers; while the non-polar groups can wrap the leather fibers, increase the distance between the leather fibers, improve the relative sliding performance of the leather fibers, reduce the friction between the leather fibers, and thus give the finished leather excellent softness.

[0025] More specifically:

[0026] Sulfonic acid groups can give fatliquoring agents good emulsification, dispersion and penetration properties, and can combine with Cr(III) in leather to bind to chrome tanned leather, enhancing the degree of cross-linking between collagen fibers and thus improving the mechanical properties of the finished leather; secondary amino groups can provide cationic groups to fatliquoring agents, increasing the polar groups of fatliquoring agents and improving the binding ability of fatliquoring agents to leather fibers; diester structure can provide oiliness and silkiness to fatliquoring leather.

[0027] 2. The preparation method of the present invention first uses long-chain fatty alcohols, maleic anhydride and diethanolamine as raw materials for esterification reaction, and then uses sodium metabisulfite as raw material for sulfonation reaction. All raw materials used are common chemical materials, which can effectively reduce the cost of amphoteric fatliquoring agents and facilitate large-scale production. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 These are infrared spectra of some of the raw materials and products in Example 1. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0031] Example 1

[0032] This embodiment provides a method for preparing a fatliquoring agent for amphoteric leather, the method comprising the following steps:

[0033] (1) Pour 196g of 12,14 alcohol into a four-necked flask, heat to 70°C, and remove the water by vacuuming.

[0034] (2) Add 98g maleic anhydride and 1g anhydrous sodium acetate to a four-necked flask under stirring, and react at 90℃;

[0035] (3) When the acid value of the reaction system reaches 190-200, add 52.5g of diethanolamine and 1g of phosphorous acid to the four-necked flask, and heat to 190℃ to continue the reaction.

[0036] (4) After the acid value of the reaction system reaches 5-8, cool down, add 95g sodium metabisulfite, 1g ethylene glycol and 200g water, and react at 80℃ for 5h. After the reaction is completed, the amphoteric leather fatliquoring agent is obtained.

[0037] Example 2

[0038] This embodiment provides a method for preparing a fatliquoring agent for amphoteric leather, the method comprising the following steps:

[0039] (1) Pour 260g of 16,18 alcohol into a four-necked flask, heat to 70°C, and remove the water by vacuuming.

[0040] (2) Add 98g maleic anhydride and 1g anhydrous sodium acetate to a four-necked flask under stirring, and react at 100℃.

[0041] (3) When the acid value of the reaction system reaches 185-195, add 52.5g of diethanolamine and 1g of phosphorous acid to the four-necked flask, and heat to 200℃ to continue the reaction.

[0042] (4) When the acid value of the reaction system reaches 7-10, the temperature is lowered, 95g of sodium sulfite, 1g of ethylene glycol and 300g of water are added, and the reaction is carried out at 90℃ for 4 hours. After the reaction is completed, the amphoteric leather fatliquoring agent is obtained.

[0043] Examples 3 to 7

[0044] The difference between Examples 3 to 7 and Example 1 is that the selection of long-chain fatty alcohols in step (1) is different, as shown in Table 1.

[0045] Table 1

[0046] Group Types of long-chain fatty alcohols Dosage Example 3 decaol 158 Example 4 dodecanol 186 Example 5 Isomerized tridecyl alcohol 200 Example 6 Tetradecyl alcohol 214 Example 7 Etioli 298

[0047] Verification Example

[0048] Using Example 1 as an example, the successful preparation of the product was verified as follows:

[0049] refer to Figure 1 The infrared spectra of maleic anhydride, maleic anhydride 12,14 ester (product of step 2), maleic anhydride 12,14-diethanolamine diester (product of step 3), and amphoteric leather fatliquoring agent (product of step 4) are shown.

[0050] Depend on Figure 1 It can be seen that 1850 and 1782cm -1 The peak at 1640 cm⁻¹ is the absorption peak of the C=O stretching vibration in maleic anhydride. -1 The peak at that position is the stretching vibration peak of C=C in maleic anhydride (the first infrared spectrum from top to bottom).

[0051] In the infrared spectrum of maleic anhydride 12,14 ester (product of step 2), 1850 -1 1782cm -1 The peak at that point disappeared, replaced by 3394cm. -1 The stretching vibration peak of -OH in the carboxyl group and 1731 cm⁻¹ -1 The presence of the stretching vibration peaks at C=O in the ester bond indicates that maleic anhydride has successfully undergone esterification with 12,14-ol, and that a carboxyl group has been retained, creating conditions for the third step of esterification with diethanolamine. Simultaneously, at 1640 cm⁻¹... -1 The presence of the C=C peak indicates that the C=C in maleic anhydride is retained, which is the basis for the fourth step of the sulfonation reaction (second infrared spectrum from top to bottom).

[0052] Compared to maleic anhydride 12,14 ester (product of step 2), the infrared spectrum of maleic anhydride 12,14-diethanolamine diester (product of step 3) shows a higher concentration of 1731. -1 1640cm -1 The significantly increased relative integrated area of ​​the peak indicates an increase in the number of C=O and C=C bonds in the molecule. Additionally, the peak at 3394 cm⁻¹ in maleic anhydride 12,14-diethanolamine diester (the product of step 3) shows a significant increase. -1 The broad peak representing the carboxyl group disappears at 3420 cm⁻¹. -1 The presence of the stretching vibration peak of NH in the secondary amine group indicates that maleic anhydride 12,14 ester (the product of step 2) has successfully undergone esterification with diethanolamine (third infrared spectrum from top to bottom).

[0053] In the infrared spectrum of the amphoteric leather fatliquoring agent (product of step 4), 1640 cm⁻¹ -1 The disappearance of the characteristic peak at C=C indicates that the C=C in maleic anhydride 12,14-diethanolamine diester (product of step 3) successfully participated in the addition reaction. The 1600 cm⁻¹ peak in the amphoteric leather fatliquoring agent (product of step 4)... -1 The peak at 1050 cm⁻¹ is the antisymmetric stretching vibration peak of -COO-. -1 The peak at 1640 cm⁻¹ represents the asymmetric vibration of the sulfonic acid group. Compared to maleic anhydride 12,14-diethanolamine diester (product of step 3), the peak at 1640 cm⁻¹ in the amphoteric leather fatliquoring agent (product of step 4) is more pronounced. -1 The disappearance of the peak and 1050cm -1 The appearance of the peak indicates that maleic anhydride 12,14-diethanolamine diester (the product of step 3) has undergone sulfonation reaction with sodium metabisulfite, indicating that the preparation has been successful.

[0054] Comparative test cases

[0055] Comparative objects: the amphoteric leather fatliquoring agent obtained in Example 1 (hereinafter referred to as "fatliquoring agent-1"), the amphoteric leather fatliquoring agent obtained in Example 2 (hereinafter referred to as "fatliquoring agent-2"), commercially available sulfonated castor oil fatliquoring agent (MF), and the blank group (untreated leather).

[0056] The test results are shown in Table 2.

[0057] Table 2

[0058]

[0059]

[0060] The analysis is as follows:

[0061] Softness is one of the important properties of finished leather. Table 2 shows the softness of leathers after fatliquoring with fatliquoring agents-1,-2, and MF. As can be seen from the table, the softness of leathers after fatliquoring with fatliquoring agents-1 and-2 is significantly improved, and is superior to the leather samples after fatliquoring with MF. Fatliquoring agents mainly improve the softness of finished leather by dispersing collagen fibers and reducing friction between fibers. Fatliquoring agents-1 and-2 contain polar groups such as sulfonic acid groups and secondary amino groups in their structure, which are affinity-dependent on the polar groups of leather fibers. The non-polar groups encapsulate the leather fibers, increasing the distance between them, improving their relative sliding properties, and reducing friction between leather fibers, thus giving the finished leather excellent softness. Because fatliquoring agents-1 and-2 have good dispersion and penetration properties, they can deeply disperse leather fibers, resulting in a softer finished leather than sulfonated castor oil fatliquoring agent MF.

[0062] Tensile strength, elongation at break, and tear strength are important mechanical properties of finished leather, significantly impacting its application range and durability. Table 2 shows that the tensile strength, elongation at break, and tear strength of leathers treated with fatliquoring agents-1,-2, and MF are all improved compared to the untreated leather blank and MF. This is because fatliquoring agents-1 and-2 have good dispersion and penetration properties, allowing them to penetrate deep into the leather fibers. Furthermore, the sulfonic acid groups in fatliquoring agents-1 and-2 can bind with Cr(III) in the leather, binding it to chrome-tanned leather and enhancing the cross-linking degree between collagen fibers, thereby improving the mechanical properties of the finished leather.

[0063] Organic solvent resistance is an important performance characteristic of finished leather and one of the indicators of the bonding strength between the fatliquoring agent and leather fibers. The better the organic solvent resistance of the finished leather, the stronger the bond between the fatliquoring agent and the leather fibers. Table 2 shows the organic solvent resistance of the finished leather after fatliquoring with fatliquoring agents-1,-2, and MF. The dichloromethane extract content of the finished leather after fatliquoring with fatliquoring agents-1 and-2 is basically equivalent to that of MF. The dichloromethane extract content of the finished leather is related to the composition and structure of the fatliquoring agent. Fatliquoring agents-1,-2, and MF all contain sulfonic acid groups, which can combine with Cr(III) in the leather. Therefore, the dichloromethane extract content of the finished leather after fatliquoring with fatliquoring agents-1,-2, and MF is comparable.

[0064] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A fatliquoring agent for amphoteric leather, characterized in that, The amphoteric leather fatliquoring agent is shown in Formula I: Formula I, Where n = 10~20; The preparation method of the amphoteric leather fatliquoring agent includes the following steps: (1) Mix long-chain fatty alcohols, maleic anhydride and catalyst for reaction; (2) When the acid value of the reaction system reaches 180-200, diethanolamine and catalyst are added to continue the reaction; (3) When the acid value of the reaction system reaches 0~10, sodium metabisulfite, phase transfer agent and water are added to continue the reaction. After the reaction is completed, the amphoteric leather fatliquoring agent is obtained.

2. The amphoteric leather fatliquoring agent according to claim 1, characterized in that, The n = 10, 12, 13, 14, 16, 18 or 20.

3. The method for preparing the amphoteric leather fatliquoring agent according to claim 1 or 2, characterized in that, The preparation method includes the following steps: (1) Mix long-chain fatty alcohols, maleic anhydride and catalyst for reaction; (2) When the acid value of the reaction system reaches 180-200, diethanolamine and catalyst are added to continue the reaction; (3) When the acid value of the reaction system reaches 0~10, sodium metabisulfite, phase transfer agent and water are added to continue the reaction. After the reaction is completed, the amphoteric leather fatliquoring agent is obtained.

4. The preparation method according to claim 3, characterized in that, In step (1), the long-chain fatty alcohol is one of deca-ol, dodeca-ol, isotridecyl alcohol, tetradecyl alcohol, 12-14 alcohol, 16-18 alcohol, and eicosyl alcohol; And / or, the catalyst is anhydrous sodium acetate.

5. The preparation method according to claim 3, characterized in that, In step (1), the reaction temperature is 90~100℃.

6. The preparation method according to claim 3, characterized in that, In step (2), the catalyst is phosphorous acid; And / or, the temperature of the reaction is 190~200℃.

7. The preparation method according to claim 3, characterized in that, In step (3), the phase transfer agent is ethylene glycol; And / or, the reaction temperature is 80~90℃, and the reaction time is 4~5h.

8. The preparation method according to claim 3, characterized in that, By weight, the long-chain fatty alcohol is 400 parts, maleic anhydride is 400 parts, diethanolamine is 200 parts, and sodium metabisulfite is 200 parts.

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