An environmentally friendly polypeptide-based water-based lubricant additive and its preparation method

Abstract

This invention relates to an environmentally friendly polypeptide-based water-based lubricant additive and its preparation method. The additive is a polypeptide component extracted from fishery waste such as fish skin, exhibiting good biodegradability, good solubility in water-glycol lubricating fluid, and good friction-reducing effects. The polypeptide additive involved in this invention is an environmentally friendly friction modifier.

Description

Technical Field

[0001] This invention belongs to the field of lubricating materials, specifically relating to an environmentally friendly polypeptide-based water-based lubricating additive and its preparation method. Background Technology

[0002] In the field of industrial lubrication, water-based lubricants, with their excellent cooling, flame-retardant, high thermal conductivity, and high specific heat capacity, are widely used in metal processing processes such as cutting, grinding, drawing, and rolling, as well as in hydraulic transmission. Compared with oil-based lubricants, water-based lubricants are environmentally friendly, resource-rich, and inexpensive, and are gradually becoming the main products in the metalworking fluid market. Water-based lubrication is essentially in a boundary lubrication state, making it difficult to establish an effective fluid lubrication film. Anti-wear and friction-reducing effects are only achieved through the boundary lubrication film formed on the friction pair surfaces by additives. Therefore, high-performance water-soluble lubricating additives are key to improving the performance of water-based lubricants and expanding their application range.

[0003] Currently, most commercially available water-based friction modifiers are based on commonly used oil-based additives. They improve their solubility in water by adding water-soluble groups to their molecular structure. Therefore, these additives still retain elements such as sulfur and phosphorus, which are prone to environmental pollution, found in oil-based additives. With societal development and increasing public awareness of environmental issues, related policies and regulations are becoming increasingly stringent, leading to the gradual restriction of the use of additives with high ecotoxicity and poor biodegradability. In recent years, developing environmentally friendly green lubricating additives using natural products as raw materials has become an important development direction in the field of lubricating materials research.

[0004] This invention relates to a polypeptide extracted from fish processing waste such as fish skin. It is inexpensive and has good water solubility and biodegradability, causing no pollution to the natural environment. It has the potential to become a new type of environmentally friendly water-based lubricant additive. Summary of the Invention

[0005] The purpose of this invention is to provide an environmentally friendly polypeptide-based water-based lubricant additive that can reduce friction in water-based lubricants.

[0006] The environmentally friendly polypeptide-based water-based lubricant additive of the present invention is extracted from fish processing waste such as fish skin, and has the characteristics of good water solubility and biodegradability, and does not pollute the natural environment.

[0007] The environmentally friendly polypeptide-based water-based lubricant of the present invention is characterized in that: the polypeptide-based water-based lubricant is composed of a variety of amino acids selected from aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, and arginine.

[0008] Furthermore, the content of aspartic acid is 5-7 g / 100g, the content of threonine is 5-7 g / 100g, the content of serine is 2-3 g / 100g, the content of glutamic acid is 10-13 g / 100g, the content of proline is 10-13 g / 100g, the content of glycine is 25-27 g / 100g, the content of alanine is 10-11 g / 100g, the content of valine is 2-3 g / 100g, the content of methionine is 1-2 g / 100g, the content of isoleucine is 1-2 g / 100g, the content of leucine is 2-3 g / 100g, the content of tyrosine is 0-1 g / 100g, the content of phenylalanine is 1-3 g / 100g, the content of lysine is 3-5 g / 100g, and the content of histidine is 0-2 g / 100g. The content of arginine is 8-9 g / 100g.

[0009] The environmentally friendly polypeptide-based water-based lubricant additive of the present invention is prepared by:

[0010] 1) After crushing the fish skin, add pure water at a ratio of fish skin to pure water of 1:8, add 2% collagenase, enzymatically hydrolyze at 50°C for 4 h, centrifuge to collect the supernatant, spray dry to obtain crude extract of fish skin polypeptides.

[0011] 2) After pretreatment, BMKX-5 macroporous adsorption resin was packed into a column. 10 g of crude fish skin polypeptide extract was dissolved in 2 BV of water and then loaded onto the column for adsorption. The adsorption residue was discarded.

[0012] 3) Add 10 BV of water, 30% ethanol, and 75% ethanol sequentially to the resin column after adsorption for elution. Collect the corresponding eluents, concentrate and dry them to obtain fish skin polypeptides of different polarities.

[0013] Furthermore, the polypeptide-based water-based lubricating additive of the present invention can be applied to water-glycol lubricating fluid.

[0014] Furthermore, the amount of the polypeptide-based water-based lubricating additive of the present invention is 1 wt% to 3 wt%.

[0015] This invention extracts waste from fish processing, such as fish skin, turning waste into treasure and solving the problem of waste disposal. Simultaneously, it provides a polypeptide-based lubricant additive that can significantly reduce the friction coefficient of water-glycol lubricants, with a minimum reduction of 66.2%. Furthermore, this additive, extracted from fish processing waste, exhibits excellent biodegradability and biocompatibility, making it environmentally friendly and suitable for widespread application in various metalworking fluids, flame-retardant hydraulic fluids, and other water-based lubricants. Attached Figure Description

[0016] Figure 1The results are the friction coefficient determination results of the polypeptides described in Examples 1, 2, and 3 in water-glycol lubricating fluid. Specific Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings, and the scope of protection of the present invention is not limited to the following embodiments.

[0018] Example 1

[0019] 1) After crushing the fish skin, add pure water at a material-to-liquid ratio of 1:8, add 2% collagenase, and enzymatically hydrolyze at 50°C for 4 hours. Centrifuge to collect the supernatant, and spray dry to obtain crude extract of fish skin polypeptides.

[0020] 2) After pretreatment, BMKX-5 macroporous adsorption resin was packed into a column. 10 g of crude fish skin polypeptide extract was dissolved in 2 BV of water and then loaded onto the column for adsorption. The adsorption residue was discarded.

[0021] 3) Add 10 BV of water to the adsorbed resin column for elution, collect the eluent and concentrate and dry it to obtain a fish skin polypeptide.

[0022] 4) The amino acid composition of the polypeptide was determined according to the standard method (GB 5009.124-2016), specifically: aspartic acid 7.4 g / 100g, threonine 2.86 g / 100g, serine 5.96 g / 100g, glutamic acid 12.2 g / 100g, proline 10.5 g / 100g, glycine 26.1 g / 100g, alanine 10.7 g / 100g, valine 2.18 g / 100g, methionine 1.44 g / 100g, isoleucine 1.28 g / 100g, leucine 2.26 g / 100g, tyrosine 0.12 g / 100g, and phenylalanine 1.03 g / 100g. The content of lysine is 4.5 g / 100g, the content of histidine is 0.98 g / 100g, and the content of arginine is 8.98 g / 100g.

[0023] Example 2

[0024] 1) After crushing the fish skin, add pure water at a ratio of 1:8 and add 2% collagenase. Enzymatically hydrolyze at 50°C for 4 hours, centrifuge to collect the supernatant, and spray dry to obtain crude extract of fish skin polypeptides.

[0025] 2) After pretreatment, BMKX-5 macroporous adsorption resin was packed into a column. 10 g of crude fish skin polypeptide extract was dissolved in 2 BV of water and then loaded onto the column for adsorption. The adsorption residue was discarded.

[0026] 3) After eluting with 10 BV of water into the resin column after adsorption, elute with 30% ethanol, collect the 30% ethanol eluent, concentrate and dry it to obtain a fish skin polypeptide.

[0027] 4) The amino acid composition of the polypeptide was determined according to the standard method (GB 5009.124-2016), specifically: aspartic acid 6.79 g / 100g, threonine 2.75 g / 100g, serine 5.8 g / 100g, glutamic acid 10.8 g / 100g, proline 12.61 g / 100g, glycine 26 g / 100g, alanine 9.44 g / 100g, valine 2.36 g / 100g, methionine 2 g / 100g, isoleucine 1.37 g / 100g, leucine 2.88 g / 100g, tyrosine 0.23 g / 100g, phenylalanine 2.4 g / 100g, and lysine 3.94 g / 100g. The content of histidine is 1.14 g / 100g, and the content of arginine is 8.29 g / 100g.

[0028] Example 3

[0029] 1) After crushing the fish skin, add pure water at a ratio of 1:8 and add 2% collagenase. Enzymatically hydrolyze at 50°C for 4 hours, centrifuge to collect the supernatant, and spray dry to obtain crude extract of fish skin polypeptides.

[0030] 2) After pretreatment, BMKX-5 macroporous adsorption resin was packed into a column. 10 g of crude fish skin polypeptide extract was dissolved in 2 BV of water and then loaded onto the column for adsorption. The adsorption residue was discarded.

[0031] 3) Add 10 BV of water and 30% ethanol to the adsorbed resin column, elute with 50% ethanol, collect the 50% ethanol eluent, concentrate and dry to obtain a fish skin polypeptide.

[0032] 4) The amino acid composition of the polypeptide was determined according to the standard method (GB 5009.124-2016), specifically: aspartic acid 7.02 g / 100g, threonine 2.82 g / 100g, serine 5.79 g / 100g, glutamic acid 11.1 g / 100g, proline 11.2 g / 100g, glycine 26.2 g / 100g, alanine 10 g / 100g, valine 2.24 g / 100g, methionine 1.66 g / 100g, isoleucine 1.38 g / 100g, leucine 2.59 g / 100g, tyrosine 0.16 g / 100g, and phenylalanine 1.74 g / 100g. The content of lysine is 4.21 g / 100g, the content of histidine is 1.17 g / 100g, and the content of arginine is 8.78 g / 100g.

[0033] The peptides prepared in Examples 1-3 were added to water-glycol (1:1, v / v) lubricant at concentrations of 1%, 2%, and 3%, respectively. The coefficient of friction was tested using a four-ball tester (test conditions: 294 N, 30 min, 25°C, 1200 rpm). The results are as follows: Figure 1 As shown. Figure 1 As shown, the polypeptide-based water-based lubricant additive of this invention can significantly reduce the friction coefficient of water-glycol lubricant, with a minimum reduction of 66.2%. The results indicate that polypeptides have excellent friction-reducing properties and have the potential to become a novel type of water-based lubricant additive.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The application of an environmentally friendly polypeptide-based water-based lubricant additive, characterized in that: The polypeptide-based water-based lubricant additive has good water solubility and biodegradability, and is composed of a variety of amino acids including aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, and arginine. The preparation method of this polypeptide-based water-based lubricating additive specifically includes the following steps: 1) After crushing the fish skin, add pure water at a ratio of fish skin to pure water of 1:8, add 2% collagenase, enzymatically hydrolyze at 50°C for 4 hours, centrifuge to collect the supernatant, spray dry to obtain crude extract of fish skin polypeptides. 2) After pretreatment, BMKX-5 macroporous adsorption resin was packed into a column. 10g of crude fish skin polypeptide extract was dissolved in 2BV of water and then loaded onto the column for adsorption. The adsorption residue was discarded. 3) Add 10 BV of water, 30% ethanol, and 75% ethanol sequentially to the resin column after adsorption for elution. Collect the corresponding eluents, concentrate and dry them to obtain fish skin polypeptides of different polarities. This environmentally friendly peptide-based water-based lubricant additive is used in water-glycol lubricants.

2. The application of the environmentally friendly polypeptide-based water-based lubricant additive according to claim 1, characterized in that: The content of aspartic acid is 5-7g / 100g, the content of threonine is 5-7g / 100g, the content of serine is 2-3g / 100g, the content of glutamic acid is 10-13g / 100g, the content of proline is 10-13g / 100g, the content of glycine is 25-27g / 100g, the content of alanine is 10-11g / 100g, and the content of valine is 2-3g / 100g. 0g, methionine content is 1-2g / 100g, isoleucine content is 1-2g / 100g, leucine content is 2-3g / 100g, tyrosine content is 0-1g / 100g, phenylalanine content is 1-3g / 100g, lysine content is 3-5g / 100g, histidine content is 0-2g / 100g, and arginine content is 8-9g / 100g.

3. The application of the environmentally friendly polypeptide-based water-based lubricant additive as described in claim 2, characterized in that: The environmentally friendly polypeptide-based water-based lubricant additive is used in water-glycol lubricants at a dosage of 1 wt% to 3 wt%.

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