CN115785381A - Waterborne polyurethane surface layer resin for environment-friendly synthetic leather and preparation method thereof - Google Patents
Waterborne polyurethane surface layer resin for environment-friendly synthetic leather and preparation method thereof Download PDFInfo
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Abstract
The invention discloses an aqueous polyurethane surface layer resin for environmental-friendly synthetic leather and a preparation method thereof, wherein the aqueous polyurethane surface layer resin comprises the following components: 7-11% of diisocyanate, 17-22% of polymer diol, 0.9-1.5% of nonionic hydrophilic chain extender, 0.5-0.7% of tertiary amine polyol chain extender, 0.7-1.0% of micromolecular diol chain extender, 0.1-0.4% of micromolecular diamine chain extender, 0.002-0.005% of catalyst, 6-12% of diluent and 55-65% of deionized water. According to the waterborne polyurethane surface layer resin for the environment-friendly synthetic leather and the preparation method thereof, the waterborne polyurethane surface layer resin not only has excellent hydrolysis resistance and heat resistance, but also solves the problems that the existing waterborne polyurethane surface layer and a solvent-free middle layer are not firmly combined and the peel strength is low.
Description
Technical Field
The invention belongs to the technical field of resin used for synthetic leather, and particularly relates to waterborne polyurethane surface resin for environment-friendly synthetic leather and a preparation method thereof.
Background
Since the 21 st century, synthetic leather products are successfully applied to various fields such as sofas, clothes, shoe materials, electronic packages, decorations and the like with excellent performance and gorgeous appearance, but the traditional synthetic leather products still adopt a large amount of toxic and harmful solvents such as DMF (dimethyl formamide), butanone, ethyl acetate and the like, and the synthetic leather industry also caters to a new generation of environment-friendly synthetic leather products under the background of environment-friendly and green manufacturing: aqueous solvent-free synthetic leather. The polyurethane foam material is prepared by matching waterborne polyurethane surface resin with a solvent-free foaming layer and attaching an environment-friendly base material.
However, the problems of low peel strength, even direct delamination between the solvent-free layer and the surface layer and the like caused by poor binding force between the aqueous polyurethane resin and the solvent-free two-component foaming layer limit the production application of the aqueous solvent-free synthetic leather. Researches of researchers find that the surface-bottom delamination phenomenon is related to dimethylolpropionic acid (DMPA) introduced into the waterborne polyurethane, and when the waterborne polyurethane is dried to form a film, the surface polyurethane is weakly acidic and can influence the molecular chain growth of the two-component solvent-free foaming layer.
On the basis of the theory, chinese patent CN10835401B discloses a waterborne polyurethane surface layer resin which is well combined with a two-component solvent-free layer, in the patent, the waterborne polyurethane is prepared by adopting a nonionic hydrophilic chain extender and self-made sodium sulfonate polymer polyol as raw materials, although the influence of DMPA on the waterborne polyurethane surface layer is avoided, the synthetic stability of the sodium sulfonate polymer polyol is a difficult problem in domestic industry because of high melting point, strong polarity and poor solubility of sodium sulfonate monomers. Although the waterborne polyurethane synthesized by adopting the nonionic hydrophilic chain extender and the self-made sodium sulfonate polymer polyol cannot become weak acid after being dried and formed into a film, and can be stripped by matching with some two-component solvent-free layers, the problem of low stripping still occurs when some two-component solvent-free layers contain a delayed acid catalyst. Chinese patent CN112521581A also discloses a waterborne polyurethane surface resin combined with a solvent-free layer, in which, the post-chain extension adopts diamine chain extender N, N' -bis (2-hydroxyethyl) ethylenediamine with hydroxyl to prepare the waterborne polyurethane surface resin, and active hydroxyl group capable of reacting with the solvent-free layer is introduced into the molecular chain to improve the peeling strength between the solvent-free layer and the waterborne polyurethane surface layer. However, technicians in the field of aqueous polyurethane synthesis have a consensus, the post-chain extension efficiency after emulsification is generally low, and most of aqueous polyurethane resins contain more amino groups and hydroxyl groups on molecular chains, so that how much help to improve the peeling strength between a solvent-free layer and an aqueous polyurethane surface layer is required to be further proved by introducing a small amount of active hydroxyl groups through post-chain extension alone.
Disclosure of Invention
Based on the technical problems, the invention provides the waterborne polyurethane surface layer resin for the environment-friendly synthetic leather and the preparation method thereof.
The invention provides an environment-friendly waterborne polyurethane surface layer resin for synthetic leather, which comprises the following raw materials in percentage by mass: 7-11% of diisocyanate, 17-22% of polymer diol, 0.9-1.5% of nonionic hydrophilic chain extender, 0.5-0.7% of tertiary amine polyol chain extender, 0.7-1.0% of micromolecular diol chain extender, 0.1-0.4% of micromolecular diamine chain extender, 0.002-0.005% of catalyst, 6-12% of diluent and 55-65% of deionized water.
According to the invention, the non-ionic hydrophilic chain extender and the tertiary amine type polyhydric alcohol chain extender are compounded to be used as the chain extender to synthesize the waterborne polyurethane surface layer resin, so that the weak acidic influence of anions such as carboxylate or sulfonate on the emulsion is avoided, the waterborne polyurethane surface layer resin is weakly alkaline, the molecular chain growth reaction of the two-component solvent-free foaming layer is promoted, the chemical bonding effect is formed between the surface layer and the foaming layer, and the bonding force and the peeling strength of the waterborne polyurethane surface layer and the solvent-free middle layer are greatly improved.
Preferably, the diisocyanate is an aromatic diisocyanate and/or an aliphatic diisocyanate;
preferably, the diisocyanate is a mixture of aromatic diisocyanate and aliphatic diisocyanate, and the molar ratio of the aromatic diisocyanate to the aliphatic diisocyanate is 1;
preferably, the aromatic diisocyanate is at least one of 2, 4-diphenylmethane diisocyanate, 2, 4-toluene diisocyanate or p-phenylene diisocyanate; the aliphatic diisocyanate is at least one of isophorone diisocyanate, hexamethylene diisocyanate or 4, 4-dicyclohexylmethane diisocyanate.
In the invention, the inventor finds that when aromatic diisocyanate and aliphatic diisocyanate are compounded to be used as diisocyanate, the obtained waterborne polyurethane surface layer resin and the solvent-free middle layer resin have more advantages in molecular matching, mutual attraction and crystallization, so that the binding force and hydrogen bond action of the waterborne polyurethane surface layer and the solvent-free middle layer are also improved, and meanwhile, the obtained polyurethane film has more excellent mechanical property and wear resistance due to the introduction of the aromatic diisocyanate into a waterborne polyurethane molecular chain. And when the molar ratio of the aromatic diisocyanate to the aliphatic diisocyanate is 1-2, the obtained waterborne polyurethane surface resin has the best matching effect with the solvent-free foaming layer resin, and the peel strength between the waterborne polyurethane surface resin and the solvent-free foaming layer resin is larger.
Preferably, the polymer diol is polyether diol and/or polyester diol;
preferably, the polymer diol is a mixture of polyether diol and polyester diol, and the mass ratio of the polyether diol to the polyester diol is 2-3;
preferably, the number average molecular weight of the polymer diol is 1500 to 2500g/mol;
preferably, the polyether diol is at least one of polytetrahydrofuran diol, polyethylene glycol or polypropylene glycol, and the polyester diol is at least one of polycarbonate diol, 1, 4-butanediol adipate diol or ethylene glycol adipate diol.
Preferably, the nonionic hydrophilic chain extender is a hydroxyl-terminated polyether with a "Y" type structure, and a specific structural schematic can be shown in FIG. 1;
preferably, the non-ionic hydrophilic chain extender is YmerN120.
Preferably, the tertiary amine type polyol chain extender is at least one of N-methyldiethanolamine, N-ethyldiethanolamine or N-propyldiethanolamine;
preferably, the mass ratio of the tertiary amine type polyol chain extender to the nonionic hydrophilic chain extender is 1.7-2.4.
In the invention, the inventor finds that the alkalinity provided by the tertiary amine type polyol chain extender is proper compared with that provided by the secondary amine type polyol chain extender, so that the molecular chain growth reaction of the two-component solvent-free intermediate layer can be effectively promoted, and the bonding force and the peeling strength between the obtained waterborne polyurethane surface layer and the solvent-free intermediate layer are improved; when the nonionic hydrophilic chain extender and the tertiary amine type polyol chain extender are compounded for use, in order to ensure that the bonding force between the obtained waterborne polyurethane surface layer resin and the two-component middle layer is optimal, the proportion of the nonionic hydrophilic chain extender and the tertiary amine type polyol chain extender needs to be properly controlled, and the mass ratio of the tertiary amine type polyol chain extender to the nonionic hydrophilic chain extender is specifically limited to 1.7-2.4.
Preferably, the small molecule diol chain extender is at least one of ethylene glycol, 1, 2-propylene glycol, 1, 4-butanediol or neopentyl glycol; the small molecular diamine chain extender is at least one of ethylenediamine, propylenediamine, isophoronediamine or hexamethylenediamine.
Preferably, the catalyst is at least one of stannous octoate or dibutyltin dilaurate, and the diluent is at least one of acetone, butanone or N-methylpyrrolidone.
Preferably, the waterborne polyurethane surface layer resin also comprises 0.01-0.1% of an auxiliary agent;
preferably, the auxiliary agent is at least one of an antioxidant, a light stabilizer or an ultraviolet absorber.
The invention also provides a preparation method of the waterborne polyurethane surface layer resin for the environment-friendly synthetic leather, which comprises the following steps:
s1, mixing polymer dihydric alcohol, a non-ionic hydrophilic chain extender, a micromolecular dihydric alcohol chain extender and diisocyanate for reaction, and then adding a catalyst and a tertiary amine type polyol chain extender for reaction until NCO reaches a theoretical value to obtain a prepolymer;
s2, adding a diluent into the prepolymer for viscosity reduction, and then adding deionized water for dispersion under high-speed stirring to obtain a dispersion product;
and S3, adding a micromolecular diamine chain extender into the dispersion product to carry out chain extension reaction, and removing the diluent to obtain the waterborne polyurethane surface layer resin.
Preferably, in the step S1, the reaction temperature is 70-75 ℃, and the reaction is carried out until NCO reaches a theoretical value; in step S2, the high-speed stirring speed is 1000-1500rpm.
Compared with the prior art, the invention has the following advantages:
(1) According to the invention, the non-ionic hydrophilic chain extender and the tertiary amine type polyol chain extender are compounded to prepare the aqueous polyurethane emulsion, so that the weak acidity influence of anions such as carboxylate and sulfonate on the emulsion is successfully avoided, and meanwhile, a proper amount of micromolecule dihydric alcohol with a tertiary amine structure is introduced into a molecular chain, so that the aqueous polyurethane surface layer is weak alkaline, the molecular chain growth reaction of a two-component solvent-free material is promoted, the solvent-free material containing a weak acid delay catalyst system is tried out, and the aqueous polyurethane emulsion has wider applicability.
(2) The invention adopts a mode of blending aliphatic series and aromatic diisocyanate, greatly improves the binding force and hydrogen bond action of the waterborne polyurethane surface layer and the solvent-free material, and simultaneously introduces the aromatic diisocyanate into the molecular chain of the waterborne polyurethane, so that the polyurethane surface film has more excellent mechanical property and wear resistance.
Drawings
FIG. 1 is a schematic structural view of a hydroxyl-terminated polyether having a Y-shaped structure according to the present invention.
Detailed Description
The present invention will be described in detail with reference to specific examples, but these examples should be explicitly mentioned for illustration, but should not be construed as limiting the scope of the present invention.
The raw materials are used: PTMG-2000 (polytetrahydrofuran diol, molecular weight 2000, produced by Taiwan chemical industry Co., ltd.); PCD-5652 (polycarbonate diol, molecular weight 2000, asahi chemical production); MDI-50 (diphenylmethane diisocyanate, produced by Wawa chemical Co., ltd.); TDI (2, 4-toluene diisocyanate, manufactured by Cangzhou university); HMDI (4, 4-dicyclohexylmethane diisocyanate, produced by wanhua chemistry); IPDI (isophorone diisocyanate, wanhua chemical production); ymerN120 (nonionic hydrophilic chain extender, produced by passtor, sweden); DMPA (dimethylolpropionic acid, produced by Pastto, sweden)
N-MDEA (N-methyldiethanolamine, manufactured by SANTIATE CHEMICAL CO., LTD., shandong); EG (ethylene glycol, reagent bottle); EDA (ethylenediamine, reagent bottles); catalyst (organobismuth catalyst 8108).
Example 1
An environment-friendly waterborne polyurethane surface layer resin for synthetic leather comprises the following raw materials by mass: MDI-50:54.3g, IPDI:80g, PTMG-2000:202.35g, PCD-5652:82.65g, ymer N120:16g, N-MDEA:8g, EG:13g, EDA:4.2g, catalyst: 0.05g, antioxidant I-1010:0.3g, acetone: 138g, deionized water: 918g.
The waterborne polyurethane surface layer resin is prepared by the following method:
(1) Adding PTMG-2000, PCD-5652, ymer N120, EG and antioxidant I-1010 into a reaction bottle according to the formula, decompressing and dehydrating for 1.5h at 120 ℃, cooling the obtained mixture to 50 ℃, adding MDI-50 and IPDI, reacting for 2h at a constant temperature of 75 ℃, adding a catalyst in the reaction process, then adding N-MDEA, continuing to react for 2h at 70 ℃, sampling, determining NCO by a di-N-butylamine titration method, and stopping the reaction when the NCO is lower than a theoretical value to obtain a prepolymer;
(2) Cooling the prepolymer to 35 ℃, adding acetone for viscosity reduction, and then adding deionized water for emulsification and dispersion under high-speed stirring at 1300rpm to obtain a dispersion product;
(3) Adding EDA into the dispersion product to perform post-chain extension reaction, and then removing acetone by reduced pressure distillation at 50 ℃ to obtain the waterborne polyurethane surface resin for the environment-friendly synthetic leather.
Example 2
An environment-friendly waterborne polyurethane surface layer resin for synthetic leather comprises the following raw materials by mass: TDI:50.3g, IPDI:84g, PTMG-2000:195.35g, PCD-5652:89.65g, ymer N120:17g, N-MDEA:9g, EG:13g, EDA:4.6g, catalyst: 0.05g, antioxidant I-1010:0.3g, acetone: 140g, deionized water: 920g.
The waterborne polyurethane surface layer resin is prepared by the following method:
(1) Adding PTMG-2000, PCD-5652, ymer N120, EG and antioxidant I-1010 into a reaction bottle according to the formula, decompressing and dehydrating for 1.5h at 120 ℃, cooling the obtained mixture to 50 ℃, adding TDI and IPDI, reacting for 2h at a constant temperature of 75 ℃, supplementing a catalyst in the reaction process, then adding N-MDEA, continuing to react for 2h at 70 ℃, sampling, measuring NCO% by adopting a di-N-butylamine titration method, stopping the reaction when the NCO% is lower than a theoretical value, and obtaining a prepolymer;
(2) Cooling the prepolymer to 35 ℃, adding acetone for viscosity reduction, and then adding deionized water for emulsification and dispersion under high-speed stirring at 1300rpm to obtain a dispersion product;
(3) Adding EDA into the dispersion product to perform post-chain extension reaction, and then removing acetone by reduced pressure distillation at 50 ℃ to obtain the waterborne polyurethane surface resin for the environment-friendly synthetic leather.
Example 3
An environment-friendly waterborne polyurethane surface layer resin for synthetic leather comprises the following raw materials by mass: TDI:25.3g, MDI-5028.3g, HMDI:89g, PTMG-2000:195.35g, PCD-5652:89.65g, ymer N120:17g, N-MDEA:10g, EG:13g, EDA:4.6g, catalyst: 0.05g, antioxidant I-1010:0.3g, acetone: 140g, deionized water: 920g.
The waterborne polyurethane surface layer resin is prepared by the following method:
(1) Adding PTMG-2000, PCD-5652, ymer N120, EG and antioxidant I-1010 into a reaction bottle according to the formula, decompressing and dehydrating for 1.5h at 120 ℃, cooling the obtained mixture to 50 ℃, adding TDI, MDI-50 and HMDI, reacting for 2h at a constant temperature of 75 ℃, supplementing a catalyst in the reaction process, then adding N-MDEA, continuing to react for 2h at 70 ℃, sampling, measuring NCO by a di-N-butylamine titration method, stopping the reaction when the NCO is lower than a theoretical value, and obtaining a prepolymer;
(2) Cooling the prepolymer to 35 ℃, adding acetone for viscosity reduction, and then adding deionized water for emulsification and dispersion under high-speed stirring at 1300rpm to obtain a dispersion product;
(3) Adding EDA into the dispersion product to perform post-chain extension reaction, and then removing acetone by reduced pressure distillation at 50 ℃ to obtain the waterborne polyurethane surface resin for the environment-friendly synthetic leather.
Example 4
An environment-friendly waterborne polyurethane surface layer resin for synthetic leather comprises the following raw materials by mass: HMDI:150g, PTMG-2000:195.35g, PCD-5652:89.65g, ymer N120:17g, N-MDEA:10g, EG:13g, EDA:4.6g, catalyst: 0.05g, antioxidant I-1010:0.3g, acetone: 140g, deionized water: 920g.
The waterborne polyurethane surface layer resin is prepared by the following method:
(1) Adding PTMG-2000, PCD-5652, ymer N120, EG and antioxidant I-1010 into a reaction bottle according to the formula, decompressing and dehydrating for 1.5h at 120 ℃, cooling the obtained mixture to 50 ℃, adding HMDI, reacting for 2h at constant temperature of 90 ℃, adding a catalyst in the reaction process, then adding N-MDEA, continuing to react for 2h at 85 ℃, sampling, measuring NCO by adopting a di-N-butylamine titration method, and stopping the reaction when the NCO is lower than a theoretical value to obtain a prepolymer;
(2) Cooling the prepolymer to 35 ℃, adding acetone for viscosity reduction, and then adding deionized water for emulsification and dispersion under high-speed stirring at 1300rpm to obtain a dispersion product;
(3) Adding EDA into the dispersion product to perform post-chain extension reaction, and then distilling under reduced pressure at 50 ℃ to remove acetone to obtain the waterborne polyurethane surface layer resin for the environment-friendly synthetic leather.
Example 5
An environment-friendly waterborne polyurethane surface layer resin for synthetic leather comprises the following raw materials by mass: MDI-50:54.3g, IPDI:80g, PTMG-2000:202.35g, PCD-5652:82.65g, ymer N120:15.5g, N-MDEA:10.5g, EG:13g, EDA:4.2g, catalyst: 0.05g, antioxidant I-1010:0.3g, acetone: 138g, deionized water: 918g.
The waterborne polyurethane surface layer resin is prepared by the following method:
(1) Adding PTMG-2000, PCD-5652, ymer N120, EG and antioxidant I-1010 into a reaction bottle according to the formula, decompressing and dehydrating for 1.5h at 120 ℃, cooling the obtained mixture to 50 ℃, adding MDI-50 and IPDI, reacting for 2h at a constant temperature of 75 ℃, adding a catalyst in the reaction process, then adding N-MDEA, continuing to react for 2h at 70 ℃, sampling, determining NCO by a di-N-butylamine titration method, and stopping the reaction when the NCO is lower than a theoretical value to obtain a prepolymer;
(2) Cooling the prepolymer to 35 ℃, adding acetone for viscosity reduction, and then adding deionized water for emulsification and dispersion under high-speed stirring at 1300rpm to obtain a dispersion product;
(3) Adding EDA into the dispersion product to perform post-chain extension reaction, and then distilling under reduced pressure at 50 ℃ to remove acetone to obtain the waterborne polyurethane surface layer resin for the environment-friendly synthetic leather.
Comparative example 1
An environment-friendly waterborne polyurethane surface layer resin for synthetic leather comprises the following raw materials by mass: MDI-50:54.3g, IPDI:80g, PTMG-2000:202.35g, PCD-5652:82.65g, DMPA:10g, triethylamine: 7.53g, EG:13g, EDA:4.2g, catalyst: 0.05g, antioxidant I-1010:0.3g, acetone: 138g, deionized water: 918g.
The waterborne polyurethane surface layer resin is prepared by the following method:
(1) Adding PTMG-2000, PCD-5652, EG and antioxidant I-1010 into a reaction bottle according to the formula, decompressing and dehydrating for 1.5h at 120 ℃, cooling the obtained mixture to 50 ℃, adding MDI-50 and IPDI, reacting for 2h at a constant temperature of 75 ℃, adding a catalyst in the reaction process, then adding DMPA and a small amount of acetone, continuing to react for 2h at 65 ℃, sampling, measuring NCO by adopting a di-n-butylamine titration method, and stopping the reaction when the NCO is lower than a theoretical value to obtain a prepolymer;
(2) Cooling the prepolymer to 35 ℃, adding the residual acetone for viscosity reduction, then adding triethylamine for neutralization reaction, and adding deionized water for emulsification and dispersion under high-speed stirring at 1300rpm to obtain a dispersion product;
(3) Adding EDA into the dispersion product to perform post-chain extension reaction, and then removing acetone by reduced pressure distillation at 50 ℃ to obtain the waterborne polyurethane surface resin for the environment-friendly synthetic leather.
Comparative example 2
An environment-friendly waterborne polyurethane surface layer resin for synthetic leather comprises the following raw materials by mass: TDI:50.3g, IPDI:84g, PTMG-2000:195.35g, PCD-5652:89.65g, ymer N120:17g, EG:18g, EDA:4.6g, catalyst: 0.05g, antioxidant I-1010:0.3g, acetone: 140g, deionized water: 920g.
The waterborne polyurethane surface layer resin is prepared by the following method:
(1) Adding PTMG-2000, PCD-5652, ymer N120, EG and antioxidant I-1010 into a reaction bottle according to the formula, decompressing and dehydrating for 1.5h at 120 ℃, cooling the obtained mixture to 50 ℃, adding TDI and IPDI, reacting for 4h at 75 ℃ at constant temperature, adding a catalyst in the reaction process, sampling, measuring NCO% by a di-n-butylamine titration method, and stopping the reaction when the NCO% is lower than a theoretical value to obtain a prepolymer;
(2) Cooling the prepolymer to 35 ℃, adding acetone for viscosity reduction, and then adding deionized water for emulsification and dispersion under high-speed stirring at 1300rpm to obtain a dispersion product;
(3) Adding EDA into the dispersion product to perform post-chain extension reaction, and then removing acetone by reduced pressure distillation at 50 ℃ to obtain the waterborne polyurethane surface resin for the environment-friendly synthetic leather.
Working slurry with the viscosity of 4000CPS/25 ℃ was prepared according to the formulation shown in table 1 below, and then coated on release paper (knife gap controlled at 0.15 mm), and then dried at 120 ℃ (drying time 4 min) to obtain an aqueous surface layer; and then the two-component solvent-free material is uniformly stirred and coated on the water-based surface layer (the coating gap is controlled to be 0.3 mm), then precured at 100 ℃ (the precuring time is 1.5 min), then the base cloth is attached, finally, the base cloth is baked at 135 ℃ (the baking time is 4 min), and finally, the leather sample is peeled from the release paper.
TABLE 1 working slurry formulation for aqueous topcoats
| Starting materials | Thickening agent | Leveling agent | Aqueous black paste | Waterborne polyurethane surface resin |
| Quality (parts) | 0.4 | 0.15 | 3 | 100 |
The solvent-free middle layer generally comprises three components A, B and C, wherein the component A is a hydroxyl-terminated polymer polyol mixture, the component B is an isocyanate-terminated modified isocyanate mixture, and the component C is a catalyst; wherein the solvent-free material I can be XCNS-3007A/XCNS-3007B available from Asahi Chun chemical, and the solvent-free material II can be XCNS-2003A/XCNS-2003B available from Asahi Chun chemical.
The leather samples obtained in examples and comparative examples were tested for peel strength (peel strength test: a 3cm wide hot melt adhesive was applied to the surface of the leather sample, and after cutting, the test was performed using a universal tensile testing machine, and the peel strength was recorded), and the results are shown in table 2 below.
TABLE 2 Peel Strength of leathers from examples and comparative examples
| Peel strength (N/3 cm) | I solvent-free Material | II solvent-free material |
| Example 1 | 97 | 96 |
| Comparative example 1 | 21 | 20 |
| Example 2 | 94 | 95 |
| Comparative example 2 | 76 | 41 |
| Example 3 | 96 | 96 |
| Example 4 | 53 | 47 |
| Example 5 | 65 | 63 |
| Competitive product resin in market | 47 | 24 |
As can be seen from the above table, compared with the case that DMPA is used as the hydrophilic chain extender in comparative example 1, when the nonionic hydrophilic chain extender and the tertiary amine polyol chain extender are used for compounding in example 1, the peel strength of the aqueous polyurethane surface layer is higher than that of the two-component solvent-free layer; compared with the comparative example 2 in which the nonionic hydrophilic chain extender is adopted alone, the peel strength of the aqueous polyurethane surface layer is higher than that of the two-component solvent-free layer when the nonionic hydrophilic chain extender and the tertiary amine polyol chain extender are adopted for compounding in the example 2; compared with the method that only aliphatic diisocyanate is used as a diisocyanate source in the embodiment 4, the method that aliphatic diisocyanate and aromatic diisocyanate are simultaneously used as the diisocyanate source in the embodiment 3 obviously has higher peel strength compared with a two-component solvent-free layer; further, compared with the case that the non-ionic hydrophilic chain extender and the tertiary amine type polyol chain extender are compounded as the chain extender in the example 5, when the proportion of the non-ionic hydrophilic chain extender and the tertiary amine type polyol chain extender does not satisfy 1.7-2.4.
Therefore, the invention adopts the compounding of the nonionic hydrophilic chain extender and the tertiary amine polyol chain extender as raw materials, and adopts the blending of aliphatic diisocyanate and aromatic diisocyanate as a diisocyanate source, so that the obtained waterborne polyurethane surface resin has good bonding fastness with a two-component solvent-free layer, high peel strength and wide applicability to solvent-free materials of different systems.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (10)
1. The waterborne polyurethane surface layer resin for the environment-friendly synthetic leather is characterized by comprising the following raw materials in percentage by mass: 7-11% of diisocyanate, 17-22% of polymer diol, 0.9-1.5% of nonionic hydrophilic chain extender, 0.5-0.7% of tertiary amine polyol chain extender, 0.7-1.0% of micromolecular diol chain extender, 0.1-0.4% of micromolecular diamine chain extender, 0.002-0.005% of catalyst, 6-12% of diluent and 55-65% of deionized water.
2. The waterborne polyurethane surface layer resin for environment-friendly synthetic leather according to claim 1, wherein the diisocyanate is aromatic diisocyanate and/or aliphatic diisocyanate;
preferably, the diisocyanate is a mixture of aromatic diisocyanate and aliphatic diisocyanate, and the molar ratio of the aromatic diisocyanate to the aliphatic diisocyanate is 1;
preferably, the aromatic diisocyanate is at least one of 2, 4-diphenylmethane diisocyanate, 2, 4-toluene diisocyanate or p-phenylene diisocyanate; the aliphatic diisocyanate is at least one of isophorone diisocyanate, hexamethylene diisocyanate or 4, 4-dicyclohexylmethane diisocyanate.
3. The waterborne polyurethane surface resin for environment-friendly synthetic leather according to claim 1 or 2, wherein the polymer diol is polyether diol and/or polyester diol;
preferably, the polymer diol is a mixture of polyether diol and polyester diol, and the mass ratio of the polyether diol to the polyester diol is 2-3;
preferably, the number average molecular weight of the polymer diol is 1500 to 2500g/mol;
preferably, the polyether diol is at least one of polytetrahydrofuran diol, polyethylene glycol or polypropylene glycol, and the polyester diol is at least one of polycarbonate diol, 1, 4-butanediol adipate diol or ethylene glycol adipate diol.
4. The waterborne polyurethane surface layer resin for the environment-friendly synthetic leather according to any one of claims 1 to 3, wherein the non-ionic hydrophilic chain extender is a hydroxyl terminated polyether with a Y-shaped structure;
preferably, the non-ionic hydrophilic chain extender is YmerN120.
5. The waterborne polyurethane top layer resin for the environment-friendly synthetic leather according to any one of claims 1 to 4, wherein the tertiary amine type polyol chain extender is at least one of N-methyldiethanolamine, N-ethyldiethanolamine or N-propyldiethanolamine;
preferably, the mass ratio of the tertiary amine type polyol chain extender to the nonionic hydrophilic chain extender is 1.7-2.4.
6. The waterborne polyurethane top layer resin for the environment-friendly synthetic leather according to any one of claims 1 to 5, wherein the small molecule diol chain extender is at least one of ethylene glycol, 1, 2-propylene glycol, 1, 4-butanediol or neopentyl glycol; the small molecular diamine chain extender is at least one of ethylenediamine, propylenediamine, isophoronediamine or hexamethylenediamine.
7. The waterborne polyurethane top-layer resin for the environment-friendly synthetic leather as claimed in any one of claims 1 to 6, wherein the catalyst is at least one of stannous octoate or dibutyltin dilaurate, and the diluent is at least one of acetone, butanone or N-methylpyrrolidone.
8. The waterborne polyurethane surface resin for the environment-friendly synthetic leather as claimed in any one of claims 1 to 7, wherein the waterborne polyurethane surface resin further comprises 0.01 to 0.1 percent of an auxiliary agent;
preferably, the auxiliary agent is at least one of an antioxidant, a light stabilizer or an ultraviolet absorber.
9. A preparation method of the waterborne polyurethane surface resin for the environment-friendly synthetic leather, which is described in any one of claims 1 to 8, is characterized by comprising the following steps:
s1, mixing polymer dihydric alcohol, a non-ionic hydrophilic chain extender, a micromolecular dihydric alcohol chain extender and diisocyanate for reaction, and then adding a catalyst and a tertiary amine type polyol chain extender for reaction until NCO reaches a theoretical value to obtain a prepolymer;
s2, adding a diluent into the prepolymer for viscosity reduction, and then adding deionized water for dispersion under high-speed stirring to obtain a dispersion product;
and S3, adding a micromolecular diamine chain extender into the dispersion product to carry out chain extension reaction, and removing the diluent to obtain the waterborne polyurethane surface layer resin.
10. The preparation method of the waterborne polyurethane surface layer resin for the environment-friendly synthetic leather according to claim 9, wherein in the step S1, the reaction temperature is 70-75 ℃, and the reaction is carried out until NCO reaches a theoretical value; in step S2, the high-speed stirring speed is 1000-1500rpm.
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| CN202211487250.3A CN115785381A (en) | 2022-11-25 | 2022-11-25 | Waterborne polyurethane surface layer resin for environment-friendly synthetic leather and preparation method thereof |
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| CN202211487250.3A CN115785381A (en) | 2022-11-25 | 2022-11-25 | Waterborne polyurethane surface layer resin for environment-friendly synthetic leather and preparation method thereof |
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