Low-plasticity acrylate brightener for leather finishing and preparation method of low-plasticity acrylate brightener

Abstract

The invention belongs to the field of leather finishing, and particularly relates to a low-plasticity acrylate brightener for leather finishing and a preparation method of the low-plasticity acrylate brightener. The preparation method comprises preparation of a shell emulsion A, preparation of a shell emulsion B and preparation of a final emulsion (preparation of a core layer). Compared with an existing acrylate brightener product, the prepared emulsion adopts a polyurethane material and a protein material which are better in hand feeling as shells, an emulsifier does not need to be introduced in the polymerization process, so that the negative effect caused by migration of the emulsifier can be reduced, meanwhile, the two used materials are both raw materials better in hand feeling, and the environment friendliness is achieved. And when the shell is used as a shell of an acrylic material, the advantage of excellent hand feeling of the two materials can be introduced, so that the whole product can well solve the problem of heavy plastic feeling of a conventional acrylic brightener product.

Description

Technical Field

[0001] The invention belongs to the field of leather finishing, and in particular relates to a low-plasticity acrylic brightener for leather finishing and a preparation method thereof. Background Art

[0002] Leather finishing is a key step to improve leather surface defects and increase leather beauty and physical properties. It plays a vital role in the overall performance of leather. Leather bright layer finishing is the top layer of leather finishing and is the most important step in determining leather physical properties, especially the feel. At present, the mainstream synthetic brighteners on the market are mainly polyurethane products. After application, they can meet the requirements of chemical resistance and cold resistance, and will not cause poor feel due to cross-linking to improve physical properties. They are the most important brighteners for high-quality leather. However, the high price of raw materials makes it impossible to apply many low-value-added products. In turn, low-priced acrylic products are chosen. However, after the physical properties of acrylic products are improved through cross-linking, their feel becomes worse, especially the plastic feel becomes heavier, which cannot satisfy customers and has not been recognized by the market.

[0003] There are many studies on improving the feel and other properties of acrylic brighteners, but no reports have been found that can solve the problem of heavy plastic feel. The problem of heavy plastic feel has become the main obstacle restricting the application of acrylic products on the leather bright layer.

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

[0005] In order to solve the problems existing in the prior art, the present invention provides a method for preparing a low-plasticity acrylic brightener for leather finishing, the preparation method comprising the following steps:

[0006] (I) Preparation of Shell Emulsion A:

[0007] (I-1) mixing and dissolving a diol monomer, a polyol monomer, a dihydroxy hydrophilic chain extension monomer, a first acrylate monomer, and a polymerization inhibitor, and then adding a diisocyanate monomer to react to obtain a prepolymer;

[0008] (I-2) adding an alkaline substance to the prepolymer for neutralization, then adding it to deionized water for emulsification, and then adding an amine chain extender to obtain the shell emulsion A after chain extension;

[0009] (II) Preparation of Shell Emulsion B:

[0010] Mixing casein with deionized water, heating under stirring and adding alkaline substances, cooling after the casein is dissolved, and obtaining the shell emulsion B;

[0011] (III) Preparation of final emulsion:

[0012] (III-1) adding the shell emulsion B to the shell emulsion A under stirring, adding deionized water and heating, then adding the second acrylate monomer and continuously stirring, and then adding the initiator solution to react;

[0013] (III-2) continuing to add the third acrylate monomer and stirring continuously, and then adding the initiator solution to react;

[0014] (III-3) adding an initiator solution, removing the residual monomers in the system by continuing the reaction, and filtering after the system is cooled. The final emulsion is the low-plasticity acrylic brightener for leather finishing.

[0015] Preferably, in step (I), in the shell emulsion A, the mass ratio of the diol monomer, the polyol monomer, the dihydroxy hydrophilic chain extender monomer, the diisocyanate monomer, the polymerization inhibitor, the first acrylate monomer, the alkaline substance, and the amine chain extender in the solid product is: 20-40: 1-5: 3-10: 20-45: 0.1-1.0: 20-40: 2.5-6.5: 1.5-3.

[0016] Preferably, in step (I-1),

[0017] The diol monomer is one or a combination of polyether diol and polyester diol; the average molecular weight of the polyether diol is 1000 g / mol, 2000 g / mol or 3000 g / mol, and the average molecular weight of the polyester diol is 500 g / mol, 1000 g / mol or 2000 g / mol;

[0018] And / or, the polyol monomer is one or a combination of two or more of trimethylolpropane, pentaerythritol, and dipentaerythritol;

[0019] And / or, the dihydroxy hydrophilic chain-extending monomer is one or a combination of two or more of dimethylol propionic acid, dimethylol butyric acid, and 2-sodium sulfonate-1,4-butanediol;

[0020] and / or, the first acrylate monomer is one or a combination of two or more of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, octyl acrylate, dodecyl acrylate, and dodecyl methacrylate;

[0021] And / or, the polymerization inhibitor is one or a combination of two or more of hydroquinone, p-methoxyphenol, and p-methoxyquinol;

[0022] And / or, the diisocyanate monomer is one or a combination of two or more of isophorone diisocyanate, dicyclohexylmethane diisocyanate, and 1,6-hexamethylene diisocyanate.

[0023] Preferably, in step (I-2),

[0024] The alkaline substance is one or a combination of triethylamine and N,N-dimethylethanolamine;

[0025] And / or, the amine chain extender is one or a combination of two or more of ethylenediamine, isophoronediamine, meta-xylylenediamine, trimethylhexamethylenediamine, and adipic acid dihydrazide.

[0026] Preferably, in step (II),

[0027] The casein weight average molecular weight is 20000-40000 g / mol;

[0028] And / or, the alkaline substance is one or a combination of triethylamine and N,N-dimethylethanolamine.

[0029] Preferably, in step (III),

[0030] The second acrylic acid ester monomer is three or more of methyl methacrylate, ethyl methacrylate, acrylonitrile, styrene, acrylamide, bornyl methacrylate, glycidyl methacrylate, and diacetone acrylamide;

[0031] And / or, the third acrylate monomer is a combination of two or more of ethyl acrylate, butyl acrylate, isooctyl acrylate, and 2-hydroxyethyl acrylate;

[0032] And / or, the initiator is a combination of an oxidant and a reducing agent; the oxidant is one or a combination of two or more selected from ammonium persulfate, potassium persulfate, sodium persulfate, and tert-butyl hydroperoxide; the reducing agent is one or a combination of two or more selected from sodium bisulfite, hydrosulfite, bleaching powder, and vitamin C; the mass ratio of the oxidant to the reducing agent is 1:0.6 to 1:1.2.

[0033] Preferably, in step (I-1), a diol monomer, a polyol monomer, and a dihydroxy hydrophilic chain extension monomer are mixed, heated to 90-110° C., stirred and dissolved, cooled to 55-65° C. after the system is homogeneous, a polymerization inhibitor and a first acrylic ester diluent monomer are added, and after the temperature stabilizes, a diisocyanate monomer is added to react and the temperature is raised to 70-80° C. for 2-3 hours to obtain a prepolymer;

[0034] In step (II), casein is mixed with deionized water, heated to 50-60° C. under stirring conditions, and an alkaline substance is added to adjust the pH to 8.5-9.5. After the casein is dissolved, the mixture is cooled to obtain the shell emulsion B.

[0035] Preferably, the mass ratio of the solid in step (I), the solid in step (II), and the solid in step (III) is 15-30:4-8:62-81.

[0036] Based on the same technical concept, another embodiment of the present invention is to provide a low-plasticity acrylic brightener for leather finishing obtained by the preparation method.

[0037] The beneficial effects of the present invention are:

[0038] Compared with the existing acrylic brightener products, the emulsion prepared by the present invention adopts a polyurethane material and a protein material with better hand feel as the shell, and does not need to introduce an emulsifier during the polymerization process, thereby reducing the negative effects caused by the migration of the emulsifier. At the same time, the two materials used are both raw materials with good hand feel. After the two are cross-linked, they are used as the shell of the acrylic material, which can introduce the advantages of the excellent hand feel of the two materials, so that the entire product can well solve the problem of heavy plastic feel of conventional acrylic brightener products. DETAILED DESCRIPTION

[0039] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0040] Example 1

[0041] This embodiment provides a method for preparing a low-plasticity acrylic brightener for leather finishing, the preparation method comprising the following steps:

[0042] (I) Preparation of Shell Emulsion A:

[0043] (I-1) 20 g of polytetrahydrofuran diol (average molecular weight 1000 g / mol, Wanhua Chemical), 3 g of trimethylolpropane, and 3 g of dimethylolpropionic acid were mixed, heated to 90° C. and stirred to dissolve, and the temperature was lowered to 55° C. after the system became homogeneous, and 0.5 g of hydroquinone and 20 g of methyl acrylate were added to dilute the monomer. After the temperature stabilized, 20 g of isophorone diisocyanate was added to react and the temperature was raised to 70° C. The reaction was carried out for 3 h to obtain a prepolymer (shell emulsion B was prepared during the heat preservation process);

[0044] (I-2) 1.4 g of triethylamine was added to the prepolymer for neutralization, and then 64.5 g of deionized water was added for emulsification, and then 0.75 g of ethylenediamine was added to obtain the shell emulsion A after chain extension, and the shell emulsion B was immediately added, and the mixture was stirred evenly for later use;

[0045] (II) Preparation of Shell Emulsion B:

[0046] 34.4 g of deionized water was added into the reaction kettle, and 9.2 g of casein (weight average molecular weight of about 20000 g / mol) was slowly added into the kettle under stirring, and the temperature was slowly raised to 50° C., and the pH value of the system was adjusted to 8.5 with triethylamine. After the casein was completely dissolved, the reaction kettle was cooled for standby use, and the shell emulsion B was obtained;

[0047] (III) Preparation of final emulsion (preparation of core layer):

[0048] (III-1) adding 96.6 g of deionized water to the mixture of the shell emulsion B and the shell emulsion A under stirring, heating the mixture to 53-55° C., then adding 40.4 g of methyl methacrylate and continuously stirring the mixture, and then adding an initiator (4 g of a 6.25% ammonium persulfate solution and 4 g of a 3.75% sodium bisulfite solution) to react, keeping the mixture at the highest temperature for 30 min, and then cooling the mixture to 53-55° C.;

[0049] (III-2) 64.4 g of ethyl acrylate was added and stirred continuously, and then an initiator (4 g of 6.25% ammonium persulfate solution and 4 g of 3.75% sodium bisulfite solution) was added to react, and the temperature was kept at the highest temperature for 30 min, and then the temperature was lowered to 63-65° C.;

[0050] (III-3) Add an initiator solution (6 g of 6.25% tert-butyl hydroperoxide and 6 g of 3.75% sodium bisulfite solution), keep the temperature at the highest temperature for 30 minutes, remove the residual monomers in the system, and filter after the system is cooled to room temperature. The final emulsion is the low-plasticity acrylic brightener for leather finishing.

[0051] Example 2

[0052] This embodiment provides a method for preparing a low-plasticity acrylic brightener for leather finishing, the preparation method comprising the following steps:

[0053] (I) Preparation of Shell Emulsion A:

[0054] (I-1) 20 g of poly(neopentyl adipate glycol) diol (average molecular weight 1000 g / mol, Wanhua Chemical), 2.9 g of trimethylolpropane, and 3.1 g of dimethylolpropionic acid were mixed, heated to 90° C. and stirred to dissolve, and the temperature was lowered to 55° C. after the system was homogeneous, 0.5 g of hydroquinone and 20 g of ethyl acrylate were added to dilute the monomer, and after the temperature stabilized, 23.6 g of dicyclohexylmethane diisocyanate was added to react and the temperature was raised to 70° C. The reaction was carried out for 3 h to obtain a prepolymer (shell emulsion B was prepared during the heat preservation process);

[0055] (I-2) adding 1.4 g of triethylamine to the prepolymer for neutralization, then adding 64.5 g of deionized water for emulsification, and then adding 0.75 g of ethylenediamine to obtain the shell emulsion A, and immediately adding the shell emulsion B, stirring evenly and setting aside;

[0056] (II) Preparation of Shell Emulsion B:

[0057] 34.4 g of deionized water was added into the reaction kettle, and 7.2 g of casein (weight average molecular weight of about 30,000 g / mol) was slowly added into the kettle under stirring, and the temperature was slowly raised to 50° C., and the pH value of the system was adjusted to 8.5 with triethylamine. After the casein was completely dissolved, the reaction kettle was cooled for standby use, and the shell emulsion B was obtained;

[0058] (III) Preparation of final emulsion (preparation of core layer):

[0059] (III-1) adding 96.6 g of deionized water to the mixture of the shell emulsion B and the shell emulsion A under stirring, heating the mixture to 53-55° C., then adding 40.4 g of methyl methacrylate and continuously stirring the mixture, and then adding an initiator (4 g of a 6.25% ammonium persulfate solution and 4 g of a 3.75% sodium bisulfite solution) to react, keeping the mixture at the highest temperature for 30 min, and then cooling the mixture to 53-55° C.;

[0060] (III-2) 54.4 g of ethyl acrylate and 10 g of n-butyl acrylate were added and stirred continuously, and then an initiator (4 g of 6.25% ammonium persulfate solution and 4 g of 3.75% sodium bisulfite solution) was added to react, and the temperature was kept at the highest temperature for 30 min, and then the temperature was lowered to 63-65° C.;

[0061] (III-3) Add an initiator solution (6 g of 6.25% tert-butyl hydroperoxide and 6 g of 3.75% sodium bisulfite solution), keep the temperature at the highest temperature for 30 minutes, remove the residual monomers in the system, and filter after the system is cooled to room temperature. The final emulsion is the low-plasticity acrylic brightener for leather finishing.

[0062] Example 3

[0063] This embodiment provides a method for preparing a low-plasticity acrylic brightener for leather finishing, the preparation method comprising the following steps:

[0064] (I) Preparation of Shell Emulsion A:

[0065] (I-1) 12.5 g of polyether diol PPG1000 (Dow) and 7.5 g of polycarbonate diol UH-100 (Ube, Japan), 3g pentaerythritol, 3g dimethylol propionic acid were mixed, heated to 90°C and stirred to dissolve, cooled to 55°C after the system was homogeneous, 0.5g hydroquinone and 20g n-butyl acrylate were added to dilute the monomer, and after the temperature stabilized, 20g isophorone diisocyanate was added to react and heated to 70°C for 3h to obtain a prepolymer (shell emulsion B was prepared during the heat preservation process);

[0066] (I-2) 1.4 g of triethylamine was added to the prepolymer for neutralization, and then 64.5 g of deionized water was added for emulsification, and then 0.625 g of hydrazine hydrate was added to obtain the shell emulsion A after chain extension, and the shell emulsion B was immediately added, and the mixture was stirred evenly for later use;

[0067] (II) Preparation of Shell Emulsion B:

[0068] 34.4 g of deionized water was added into the reaction kettle, and 10 g of casein (weight average molecular weight of about 20,000 g / mol) was slowly added into the kettle under stirring, and the temperature was slowly raised to 50° C., and the pH value of the system was adjusted to 8.5 with triethylamine. After the casein was completely dissolved, the reaction kettle was cooled for standby use, and the shell emulsion B was obtained;

[0069] (III) Preparation of final emulsion (preparation of core layer):

[0070] (III-1) adding 96.6 g of deionized water to the mixture of the shell emulsion B and the shell emulsion A under stirring, heating the mixture to 53-55° C., then adding 40.4 g of methyl methacrylate and continuously stirring the mixture, and then adding an initiator (4 g of a 6.25% ammonium persulfate solution and 4 g of a 3.75% sodium bisulfite solution) to react, keeping the mixture at the highest temperature for 30 min, and then cooling the mixture to 53-55° C.;

[0071] (III-2) 59.4 g of ethyl acrylate and 5 g of n-butyl acrylate were added and stirred continuously, and then an initiator (4 g of 6.25% ammonium persulfate solution and 4 g of 3.75% sodium bisulfite solution) was added to react, and the temperature was kept at the highest temperature for 30 min, and then the temperature was lowered to 63-65° C.;

[0072] (III-3) Add an initiator solution (6 g of 6.25% tert-butyl hydroperoxide and 6 g of 3.75% sodium bisulfite solution), keep the temperature at the highest temperature for 30 minutes, remove the residual monomers in the system, and filter after the system is cooled to room temperature. The final emulsion is the low-plasticity acrylic brightener for leather finishing.

[0073] Application effect comparison:

[0074] (I) The application formula is shown in Table 1.

[0075] Table 1

[0076]

[0077]

[0078] (II) The application process flow is shown in Table 2.

[0079] Table 2

[0080]

[0081] (III) The test results of different samples after application on skin are shown in Table 3.

[0082] Table 3

[0083]

[0084] Compared with the existing acrylic brightener, the self-made brightener sample of the present invention has significantly improved plasticity of leather after being applied to leather, reaching the level of polyurethane brightener, and has no difference in dry rubbing resistance, wet rubbing resistance, abrasion resistance and other properties.

[0085] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a low-plasticity acrylic brightener for leather finishing, characterized in that: The preparation method comprises the following steps: (I) Preparation of Shell Emulsion A: (I-1) mixing and dissolving a diol monomer, a polyol monomer, a dihydroxy hydrophilic chain extension monomer, a first acrylate monomer, and a polymerization inhibitor, and then adding a diisocyanate monomer to react to obtain a prepolymer; (I-2) adding an alkaline substance to the prepolymer for neutralization, then adding it to deionized water for emulsification, and then adding an amine chain extender to obtain the shell emulsion A after chain extension; (II) Preparation of Shell Emulsion B: Mixing casein with deionized water, heating under stirring and adding alkaline substances, cooling after the casein is dissolved, and obtaining the shell emulsion B; (III) Preparation of final emulsion: (III-1) adding the shell emulsion B to the shell emulsion A under stirring, adding deionized water and heating, then adding the second acrylate monomer and continuously stirring, and then adding the initiator solution to react; (III-2) continuing to add the third acrylate monomer and stirring continuously, and then adding the initiator solution to react; (III-3) adding an initiator solution, removing the residual monomers in the system by continuing the reaction, and filtering after the system is cooled. The final emulsion is the low-plasticity acrylic brightener for leather finishing.

2. The method for preparing the low-plasticity acrylic brightener for leather finishing according to claim 1, characterized in that: In step (I), in the shell emulsion A, the mass ratio of the diol monomer, the polyol monomer, the dihydroxy hydrophilic chain extender monomer, the diisocyanate monomer, the polymerization inhibitor, the first acrylate monomer, the alkaline substance, and the amine chain extender in the solid product is: 20-40: 1-5: 3-10: 20-45: 0.1-1.0: 20-40: 2.5-6.5: 1.5-3.

3. The method for preparing the low-plasticity acrylic brightener for leather finishing according to claim 1, characterized in that: In step (I-1), The diol monomer is one or a combination of polyether diol and polyester diol; the average molecular weight of the polyether diol is 1000 g / mol, 2000 g / mol or 3000 g / mol, and the average molecular weight of the polyester diol is 500 g / mol, 1000 g / mol or 2000 g / mol; And / or, the polyol monomer is one or a combination of two or more of trimethylolpropane, pentaerythritol, and dipentaerythritol; And / or, the dihydroxy hydrophilic chain-extending monomer is one or a combination of two or more of dimethylol propionic acid, dimethylol butyric acid, and 2-sodium sulfonate-1,4-butanediol; and / or, the first acrylate monomer is one or a combination of two or more of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, octyl acrylate, dodecyl acrylate, and dodecyl methacrylate; And / or, the polymerization inhibitor is one or a combination of two or more of hydroquinone, p-methoxyphenol, and p-methoxyquinol; And / or, the diisocyanate monomer is one or a combination of two or more of isophorone diisocyanate, dicyclohexylmethane diisocyanate, and 1,6-hexamethylene diisocyanate.

4. The method for preparing the low-plasticity acrylic brightener for leather finishing according to claim 1, characterized in that: In step (I-2), The alkaline substance is one or a combination of triethylamine and N,N-dimethylethanolamine; And / or, the amine chain extender is one or a combination of two or more of ethylenediamine, isophoronediamine, meta-xylylenediamine, trimethylhexamethylenediamine, and adipic acid dihydrazide.

5. The method for preparing the low-plasticity acrylic brightener for leather finishing according to claim 1, characterized in that: In step (II), The casein weight average molecular weight is 20000-40000 g / mol; And / or, the alkaline substance is one or a combination of triethylamine and N,N-dimethylethanolamine.

6. The method for preparing the low-plasticity acrylic brightener for leather finishing according to claim 1, characterized in that: In step (III), The second acrylic acid ester monomer is three or more of methyl methacrylate, ethyl methacrylate, acrylonitrile, styrene, acrylamide, bornyl methacrylate, glycidyl methacrylate, and diacetone acrylamide; And / or, the third acrylate monomer is a combination of two or more of ethyl acrylate, butyl acrylate, isooctyl acrylate, and 2-hydroxyethyl acrylate; And / or, the initiator is a combination of an oxidant and a reducing agent; the oxidant is one or a combination of two or more selected from ammonium persulfate, potassium persulfate, sodium persulfate, and tert-butyl hydroperoxide; the reducing agent is one or a combination of two or more selected from sodium bisulfite, hydrosulfite, bleaching powder, and vitamin C; the mass ratio of the oxidant to the reducing agent is 1:0.6 to 1:1.

2.

7. The method for preparing the low-plasticity acrylic brightener for leather finishing according to claim 1, characterized in that: In step (I-1), a diol monomer, a polyol monomer, and a dihydroxy hydrophilic chain extension monomer are mixed, heated to 90-110° C., stirred and dissolved, and cooled to 55-65° C. after the system is homogeneous, and a polymerization inhibitor and a first acrylic ester diluent monomer are added. After the temperature stabilizes, a diisocyanate monomer is added to react and the temperature is raised to 70-80° C. for 2-3 hours to obtain a prepolymer; In step (II), casein is mixed with deionized water, heated to 50-60° C. under stirring conditions, and an alkaline substance is added to adjust the pH to 8.5-9.

5. After the casein is dissolved, the mixture is cooled to obtain the shell emulsion B.

8. The method for preparing the low-plasticity acrylic brightener for leather finishing according to claim 1, characterized in that: The mass ratio of the solid in step (I), the solid in step (II), and the solid in step (III) is 15-30:4-8:62-81.

9. The low-plasticity acrylate brightener for leather finishing obtained by the preparation method according to any one of claims 1 to 8.

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