CN115491118B

CN115491118B - Water-based leather finishing agent, preparation method thereof and leather finishing process

Info

Publication number: CN115491118B
Application number: CN202211257773.9A
Authority: CN
Inventors: 崔千秋; 陈益川; 朱才桃
Original assignee: Zhejiang Nanlong Leather Co ltd
Current assignee: Zhejiang Nanlong Leather Co ltd
Priority date: 2022-10-13
Filing date: 2022-10-13
Publication date: 2023-08-08
Anticipated expiration: 2042-10-13
Also published as: CN115491118A

Abstract

The application relates to the field of finishing agents, and particularly discloses a water-based leather finishing agent, a preparation method thereof and a dermis finishing process, wherein the water-based leather finishing agent is prepared from the following components in parts by weight: 20-30 parts of polyalcohol; 15-20 parts of castor oil; 5-8 parts of 2, 2-dimethylolpropionic acid; 15-30 parts of isophorone diisocyanate; 0.1-1 part of catalyst; 30-50 parts of butanone; 3-5 parts of hydroxyethyl acrylate; 0.1-0.2 part of hydroquinone; 6-10 parts of chain extender; 1-3 parts of neutralizing agent; 0.3-0.6 part of photoinitiator; 0.2-0.5 part of leveling agent; 0.2-0.5 part of thickener; 150-200 parts of water. Castor oil is used in the finishes of the present application to replace a portion of the polyol and contains double bonds that provide a photocuring site. The content of the photo-curable unsaturated double bonds in the polyurethane synthesized by castor oil is increased, so that the crosslinking density of the coating after curing is increased, the water resistance and flexibility of the coating are improved, and the comprehensive performance of the leather after finishing is improved.

Description

Water-based leather finishing agent, preparation method thereof and leather finishing process

Technical Field

The application relates to the field of finishing agents, in particular to a water-based leather finishing agent, a preparation method thereof and a leather finishing process.

Background

The coating is an important link of leather production and processing, namely the leather coating agent is uniformly coated on the surface of leather in a brushing, spraying, showering mode and the like, so as to form a protective coating. The coating not only has the functions of beautifying the surface of the leather and increasing the variety of the colors, but also can repair the defects and improve the durability of the leather. Most of the traditional leather finishing agents are solvent-based and are easy to generate volatile organic compounds, so that the problems of environmental pollution and personal safety threat exist. In order to improve the environmental protection property of the leather finishing agent, the following aqueous polyurethane leather finishing agent is an important development direction of the finishing agent.

The Chinese patent with publication number of CN106752880A discloses an ultraviolet light curing water-based polyurethane acrylic ester leather polishing finishing agent which is prepared by mixing the following components in percentage by weight: 10 to 30 percent of polyalcohol, 10 to 40 percent of isocyanate, 2 to 10 percent of micromolecular dihydric alcohol with the molecular weight of less than 150, 2 to 5 percent of hydrophilic chain extender, 2 to 5 percent of chain extension modifier, 3 to 8 percent of acrylate end capping agent, 0.01 to 0.1 percent of catalyst, 0.01 to 0.5 percent of free radical polymerization inhibitor, 1 to 3 percent of neutralizer, 0.5 to 1 percent of water-based thickener, 3 to 5 percent of handfeel agent, 0.5 to 1 percent of wetting agent, 0.04 to 0.1 percent of flatting agent, 0.01 to 0.5 percent of photoinitiator and the balance of deionized water.

The polyurethane coating agent disclosed in the above patent is photo-curing, has the advantages of low curing temperature, short curing time, no environmental pollution and the like, combines the advantages of the ultraviolet curing technology and the water-based coating, but has the problem of insufficient water resistance compared with the solvent-based coating.

Disclosure of Invention

In order to improve the water resistance of the coating agent, the application provides a water-based leather coating agent, a preparation method thereof and a leather coating process.

In a first aspect, the present application provides a water-based leather finishing agent, which adopts the following technical scheme:

the water-based leather finishing agent is prepared from the following components in parts by weight:

20-30 parts of polyalcohol;

15-20 parts of castor oil;

5-8 parts of 2, 2-dimethylolpropionic acid;

15-30 parts of isophorone diisocyanate;

0.1-1 part of catalyst;

30-50 parts of butanone;

3-5 parts of hydroxyethyl acrylate;

0.1-0.2 part of hydroquinone;

6-10 parts of chain extender;

1-3 parts of neutralizing agent;

0.3-0.6 part of photoinitiator;

0.2-0.5 part of leveling agent;

0.2-0.5 part of thickener;

150-200 parts of water.

By adopting the technical scheme, the castor oil has a plurality of hydroxyl groups in the molecular structure, can replace a part of polyol, and the double bond contained in the castor oil can provide a photocuring site. The content of the photo-curable unsaturated double bonds in the polyurethane synthesized by castor oil is increased, so that the crosslinking density of the coating after curing is increased, the water resistance and flexibility of the coating are improved, and the comprehensive performance of the leather after finishing is improved.

In addition, the castor oil is used as biological resource, and compared with petrochemical resource, the castor oil has the advantages of low price, regeneration, environmental protection, no pollution and the like, and meets the current increasingly serious environmental protection requirement.

Optionally, the preparation process of the polyol is as follows:

step one: uniformly mixing 30-50 parts of vegetable oil, 6-10 parts of sorbitol and 0.05-0.1 part of sodium hydroxide according to parts by weight, heating to 160-170 ℃, reacting for 3-5 hours, and cooling to obtain an alcoholysis product;

step two: adding 2-4 parts of formic acid and 0.6-0.9 part of phosphoric acid into the alcoholysis product, mixing, adding 15-20 parts of 30wt% hydrogen peroxide, heating to 50-70 ℃, reacting for 4-6 hours, adding 10-15 parts of diisopropanolamine, heating to 130-150 ℃, and reacting for 3-5 hours to obtain the polyol.

According to the technical scheme, vegetable oil is used as a raw material, sorbitol is used as a raw material, sodium hydroxide is used as a catalyst to carry out alcoholysis reaction, then the alcoholysis reaction is carried out with formic acid, phosphoric acid and hydrogen peroxide, and then the hydroxylation reaction is carried out with diisopropanolamine to obtain the polyol with higher functionality.

On one hand, the polyol prepared from the vegetable oil has environmental protection significance, and on the other hand, the content of polar groups of polyurethane molecules obtained through synthesis is increased, and the number of hydrogen bonds is increased, so that the hydrogen bond effect and coulomb force are enhanced, and the wear resistance of the coating is facilitated.

Optionally, the vegetable oil is ginkgo oil.

By adopting the technical scheme, the ginkgo oil is extracted from ginkgo leaves, contains various substances such as flavonoid glycosides, terpene lactones, alcohols, aldehydes and the like, contains rich functional groups, and increases crosslinking points in polyurethane molecular chains formed by polymerization of the prepared polyol and isocyanate to form a reticular structure, so that the compactness of the coating is improved.

Optionally, the chain extender is a fluorine-containing chain extender.

By adopting the technical scheme, fluorine atoms with strong electronegativity are introduced into the polyurethane macromolecules, so that the surface energy is reduced, and the surface hydrophobicity of the coating is improved.

Optionally, the thickener is hydroxyapatite.

By adopting the technical scheme, on one hand, the hydroxyapatite is used as a thickening agent, has good thixotropic property, can improve the viscosity of the finishing agent, is beneficial to the construction of the coating and prevents the coating from sagging; on the other hand, the active hydroxyl on the surface of the coating agent can be bonded with fluorine atoms to play a role in protecting colloid, so that the emulsion is uniformly dispersed, and the comprehensive performance of the coating agent is improved.

Optionally, the catalyst is dibutyl tin dilaurate.

Optionally, the neutralizing agent is triethylamine.

In a second aspect, the present application provides a method for preparing a water-based leather finishing agent, which adopts the following technical scheme:

a preparation method of a water-based leather finishing agent comprises the following steps:

step one: mixing polyalcohol, castor oil and 2, 2-dimethylolpropionic acid according to the required weight parts of the formula, introducing nitrogen for protection, adding butanone, heating to 70-75 ℃, continuously adding isophorone diisocyanate and a catalyst, and reacting for 1.5-2 hours to obtain a prepolymer;

step two: mixing the prepolymer and a chain extender, reacting for 1.5-2 hours at 65-70 ℃, adding hydroxyethyl acrylate and hydroquinone, continuously reacting for 2-3 hours, cooling to 50-60 ℃, adding a neutralizing agent, mixing for 10-15 minutes, adding water, stirring and emulsifying for 1-2 hours, and finally steaming out butanone to obtain the waterborne polyurethane;

step three: and uniformly mixing the aqueous polyurethane, the photoinitiator, the leveling agent and the thickening agent to obtain the aqueous leather finishing agent.

In a third aspect, the present application provides a dermis finishing process, employing the following technical scheme:

a dermis finishing process comprising the steps of:

spraying the water-based leather finishing agent on the surface of the dermis, then drying in vacuum for 25min, and finally irradiating for 60s by adopting ultraviolet light to obtain the finished dermis.

Optionally, the avocado oil is brushed onto the dermis surface prior to the finish application.

By adopting the technical scheme, the avocado oil is brushed to form an oil film on the surface of the dermis, so that on one hand, a part of ultraviolet light can be isolated, the influence of the ultraviolet light curing process on the dermis performance is reduced, on the other hand, the oil film is favorable for the adhesion of a polyurethane coating agent, and the adhesive force of a coating is improved.

In summary, the present application has the following beneficial effects:

1. according to the method, castor oil and ginkgo oil are used for replacing traditional polyol to be used as raw materials for producing polyurethane, the functional groups are rich, the crosslinking density of the cured coating is increased, the comprehensive performance of the coated leather is improved, the raw materials are environment-friendly and easy to obtain, and the current environment-friendly requirement is met;

2. in the method, the fluorine-containing chain extender is adopted, and the hydroxyapatite is adopted as the thickener, so that a synergistic effect is achieved between the fluorine-containing chain extender and the hydroxyapatite, and the comprehensive performance of leather in the process of drawing is improved;

3. the avocado oil is brushed on the surface of the dermis before the coating agent is sprayed to form an oil film, so that on one hand, a part of ultraviolet light can be isolated, the influence of the ultraviolet light curing process on the dermis is reduced, on the other hand, the oil film is favorable for the adhesion of the polyurethane coating agent, and the adhesive force of the coating is improved.

Detailed Description

The present application is further described in detail with reference to the following examples, which are specifically described: the following examples, in which no specific conditions are noted, are conducted under conventional conditions or conditions recommended by the manufacturer, and the raw materials used in the following examples are commercially available from ordinary sources except for the specific descriptions.

The examples of the present application use the following raw materials:

the oleum Ginkgo is obtained from folium Ginkgo, and is purchased from Hubei department Yi Jia chemical industry Co.

Castor oil was purchased from a Weifang Zhenghua chemical company, inc.

The fluorine-containing chain extender is 2, 2-bis [4- (4-aminophenoxy) phenyl ] hexafluoropropane (BAPF 6P) purchased from Zhangjia Korea chemical Co.

The photoinitiator was 1173 and was purchased from Nanjing Milan chemical Co.

The leveling agent model was BYK-306, purchased from Pick, germany.

Preparation example 1:

the preparation process of the polyol is as follows:

step one: uniformly mixing 3kg of soybean oil, 0.6kg of sorbitol and 5g of sodium hydroxide by weight, heating to 160 ℃, reacting for 5 hours, and cooling to obtain an alcoholysis product;

step two: adding 0.2kg of formic acid and 60g of phosphoric acid into the alcoholysis product, mixing, adding 1.5kg of 30wt% hydrogen peroxide, heating to 50 ℃, reacting for 6 hours, adding 1kg of diisopropanolamine, heating to 130 ℃, and reacting for 5 hours to obtain the polyol.

Preparation example 2:

the preparation process of the polyol is as follows:

step one: uniformly mixing 5kg of soybean oil, 1kg of sorbitol and 10g of sodium hydroxide by weight, heating to 170 ℃, reacting for 3 hours, and cooling to obtain an alcoholysis product;

step two: adding 0.4kg of formic acid and 90g of phosphoric acid into the alcoholysis product, mixing, adding 2kg of 30wt% hydrogen peroxide, heating to 70 ℃, reacting for 4 hours, adding 1.5kg of diisopropanolamine, heating to 150 ℃, and reacting for 3 hours to obtain the polyol.

Preparation example 3:

the preparation process of the polyol is as follows:

step one: uniformly mixing 4kg of soybean oil, 0.8kg of sorbitol and 8g of sodium hydroxide by weight, heating to 165 ℃, reacting for 4 hours, and cooling to obtain an alcoholysis product;

step two: adding 0.3kg of formic acid and 75g of phosphoric acid into the alcoholysis product, mixing, adding 1.8kg of 30wt% hydrogen peroxide, heating to 60 ℃, reacting for 5 hours, adding 1.2kg of diisopropanolamine, heating to 140 ℃, and reacting for 4 hours to obtain the polyol.

Preparation example 4:

the only difference from preparation example 3 is that the soybean oil is replaced by ginkgo oil in equal mass.

Example 1:

the water-based leather finishing agent is prepared from the following components in mass:

2kg of the polyol prepared in preparation example 1;

1.5kg of castor oil;

0.5kg of 2, 2-dimethylolpropionic acid;

1.5kg of isophorone diisocyanate;

0.01kg of dibutyltin dilaurate;

butanone 3kg;

0.3kg of hydroxyethyl acrylate;

hydroquinone 0.01kg;

0.6kg of 1, 4-butanediol;

0.1kg of triethylamine;

0.03kg of photoinitiator;

0.02kg of leveling agent;

0.02kg of polyacrylamide;

15kg of water.

step one: mixing polyol, castor oil and 2, 2-dimethylolpropionic acid according to the required mass of the formula, introducing nitrogen for protection, adding butanone, heating to 70 ℃, continuously adding isophorone diisocyanate and dibutyltin dilaurate, and reacting for 2 hours to obtain a prepolymer;

step two: mixing the prepolymer with a chain extender, reacting for 2 hours at 65 ℃, adding hydroxyethyl acrylate and hydroquinone, continuously reacting for 3 hours, cooling to 50 ℃, adding triethylamine, mixing for 10 minutes, adding water, stirring and emulsifying for 1 hour at 1500r/min, and finally steaming out butanone to obtain waterborne polyurethane;

Example 2:

3kg of the polyol prepared in preparation example 2;

2kg of castor oil;

0.8kg of 2, 2-dimethylolpropionic acid;

3kg of isophorone diisocyanate;

0.1kg of dibutyltin dilaurate;

butanone 5kg;

0.5kg of hydroxyethyl acrylate;

hydroquinone 0.02kg;

1kg of 1, 4-butanediol;

0.3kg of triethylamine;

0.06kg of photoinitiator;

0.05kg of leveling agent;

0.05kg of polyacrylamide;

20kg of water.

step one: mixing polyol, castor oil and 2, 2-dimethylolpropionic acid according to the required mass of the formula, introducing nitrogen for protection, adding butanone, heating to 75 ℃, continuously adding isophorone diisocyanate and dibutyltin dilaurate, and reacting for 1.5 hours to obtain a prepolymer;

step two: mixing the prepolymer with a chain extender, reacting for 1.5 hours at 70 ℃, adding hydroxyethyl acrylate and hydroquinone, continuously reacting for 2 hours, cooling to 60 ℃, adding triethylamine, mixing for 15 minutes, adding water, stirring and emulsifying for 2 hours at 1500r/min, and finally steaming out butanone to obtain waterborne polyurethane;

Example 3:

2.5kg of the polyol prepared in preparation example 3;

1.8kg of castor oil;

06kg of 2, 2-dimethylolpropionic acid;

2kg of isophorone diisocyanate;

0.05kg of dibutyltin dilaurate;

4kg of butanone;

0.4kg of hydroxyethyl acrylate;

0.015kg of hydroquinone;

0.8kg of 1, 4-butanediol;

0.2kg of triethylamine;

0.05kg of photoinitiator;

0.03kg of leveling agent;

0.03kg of polyacrylamide;

18kg of water.

step one: mixing polyol, castor oil and 2, 2-dimethylolpropionic acid according to the required mass of the formula, introducing nitrogen for protection, adding butanone, heating to 72 ℃, continuously adding isophorone diisocyanate and dibutyltin dilaurate, and reacting for 1.8 hours to obtain a prepolymer;

step two: mixing the prepolymer with a chain extender, reacting for 1.8 hours at 68 ℃, adding hydroxyethyl acrylate and hydroquinone, continuously reacting for 2.5 hours, cooling to 55 ℃, adding triethylamine, mixing for 12 minutes, adding water, stirring and emulsifying for 1.5 hours at 1500r/min, and finally steaming out butanone to obtain waterborne polyurethane;

Example 4:

the only difference from example 3 is that the polyol was prepared using preparation example 4.

Example 5:

the only difference from example 4 is that the equivalent mass of 1, 4-butanediol is replaced by a fluorine-containing chain extender.

Example 6:

the only difference from example 4 is that the polyacrylamide is replaced by hydroxyapatite of equal mass.

Example 7:

the only difference from example 5 is that the equivalent mass of polyacrylamide is replaced by hydroxyapatite.

Examples 8 to 14:

the leather was finished with the aqueous leather finishes of examples 1-7 in sequence, the leather finishing process comprising the steps of:

the aqueous leather finishing agent of examples 1-7 was sprayed onto the surface of dermis, vacuum-dried at 50℃for 25min, and finally placed in a 50W UV curing apparatus, and irradiated with UV light for 60s to obtain finished dermis.

The coating thickness was measured to be about 50 μm.

Example 15:

the only difference from example 14 is that the avocado oil is brushed onto the dermis surface prior to the finish application, resulting in an oil film of about 10 μm thickness.

Comparative example 1:

the only difference from example 10 is that the equivalent mass of polyol is replaced by PPG-1000.

Comparative example 2:

the only difference from example 10 is that the equivalent mass of polyol and castor oil is replaced by PPG-1000.

And (3) environment-friendly detection:

the leathers of examples 7 to 15 were tested for an average of 38mg/kg of free formaldehyde, an average of 3.8 pH, an average of 0.5 dilution difference, and no aromatic amines such as benzidine, p-chloroaniline and o-toluidine were detected.

Waterproof performance test:

the leathers of examples 8 to 15 and comparative examples 1 to 2 were prepared into test pieces and tested for water repellency by the method described in GB/T40936-2021 determination of water repellency of leather physical and mechanical test clothing, the water repellency rating was evaluated on the basis of the water pick-up phenomenon, the water pick-up rating was 1 to 5, the 5 rating represented excellent water repellency, and the results were shown in the following Table.

Abrasion resistance test:

determination of wear resistance of leather physical and mechanical test with reference to GB/T39507-2020: the leathers of examples 8 to 15 and comparative examples 1 to 2 were prepared into test pieces, and the leather-coated surfaces were subjected to abrasion resistance test, and after each 100 times of abrasion test, the surface changes of the test pieces were observed, and the number of abrasion points on the coated surfaces was recorded until the abrasion points at 4 or more positions were found, and the number of times of abrasion at that time was recorded, and the results were shown in the following table.

Adhesion test:

the adhesive tape for packaging is tightly adhered to the leather coating, then the adhesive fastness is improved by adopting an electric iron for low-temperature ironing, finally after cooling, the adhesive tape is quickly torn off at an angle of 180 degrees, the peeling condition of the coating is observed and is divided into 1-5 grades, and the 1 grade represents that the adhesive force of the coating is most excellent.

Folding fastness test:

determination of the folding fastness in leather physical and mechanical tests, see GB/T39368-2020: the leather of examples 8 to 15 and comparative examples 1 to 2 were produced into test pieces by the method described in shoe upper bending method, and the leather was subjected to a test for folding endurance, and the number of times of folding when the test pieces were broken was recorded for 5000 times of folding, and the results are shown in the following table.

Recording table for testing leather coating performance

The present embodiment is merely illustrative of the present application and is not intended to be limiting, and those skilled in the art, after having read the present specification, may make modifications to the present embodiment without creative contribution as required, but is protected by patent laws within the scope of the claims of the present application.

Claims

1. A dermis finishing process comprising the steps of:

firstly brushing avocado oil on the surface of dermis, spraying a water-based leather finishing agent on the surface of dermis, vacuum drying for 25min, and finally irradiating for 60s by adopting ultraviolet light to obtain the finished dermis;

20-30 parts of polyalcohol;

15-20 parts of castor oil;

5-8 parts of 2, 2-dimethylolpropionic acid;

15-30 parts of isophorone diisocyanate;

0.1-1 part of catalyst;

30-50 parts of butanone;

3-5 parts of hydroxyethyl acrylate;

0.1-0.2 part of hydroquinone;

6-10 parts of chain extender;

1-3 parts of neutralizing agent;

0.3-0.6 part of photoinitiator;

0.2-0.5 part of leveling agent;

0.2-0.5 part of thickener;

150-200 parts of water;

the preparation process of the polyol is as follows:

step one: uniformly mixing 30-50 parts of ginkgo oil, 6-10 parts of sorbitol and 0.05-0.1 part of sodium hydroxide according to parts by weight, heating to 160-170 ℃, reacting for 3-5 hours, and cooling to obtain an alcoholysis product;

step two: adding 2-4 parts of formic acid and 0.6-0.9 part of phosphoric acid into the alcoholysis product, mixing, adding 15-20 parts of 30wt% hydrogen peroxide, heating to 50-70 ℃, reacting for 4-6 hours, adding 10-15 parts of diisopropanolamine, heating to 130-150 ℃, and reacting for 3-5 hours to obtain polyol;

the preparation method of the water-based leather finishing agent comprises the following steps:

2. The dermis finishing process according to claim 1, characterized in that: the chain extender is a fluorine-containing chain extender.

3. A dermis finishing process according to claim 2, characterized in that: the thickening agent is hydroxyapatite.

4. The dermis finishing process according to claim 1, characterized in that: the catalyst is dibutyl tin dilaurate.

5. The dermis finishing process according to claim 1, characterized in that: the neutralizing agent is triethylamine.