Aqueous suede coating composition for synthetic leather and method of preparation

Abstract

The application discloses a water-based suede surface layer composition for synthetic leather and a preparation method thereof, which is prepared from the following components in parts by weight: 91-98 parts of an aliphatic water-based polyurethane dispersion; 5-25 parts of polystyrene microspheres; 5-25 parts of silicone rubber powder; 1-5 parts of a crosslinking agent; 0.05-1 parts of a defoaming agent; 0.5-2 parts of a wetting agent; 0.5-2 parts of a hand feel agent; and 0.5-2 parts of a stabilizing agent. In the aliphatic water-based polyurethane dispersion, the polystyrene microspheres and the silicone rubber powder are combined to solve the unqualified phenomena such as poor leveling, shrinkage cavity and bright spots during the preparation of the suede leather. The leather product prepared from the suede surface layer has the advantages of skin feeling and suede, and can meet the physical property requirements of sofa leather.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of water-based polyurethane resin, in particular to a water-based polyurethane suede top layer composition for synthetic leather and a preparation method thereof. BACKGROUND

[0002] Synthetic leather, also known as artificial leather, is a product that imitates the structure, feel and style of real leather. Currently, the raw material for synthetic leather is mainly solvent-based polyurethane resin, and the solvents used are mainly dimethylformamide (DMF), methyl ketone (MEK), toluene (Toluene), etc. Although solvent recovery devices are used, the separation effect is not ideal, resulting in waste of resources and environmental pollution. At present, consumers have high demand for products that promote environmental protection principles, services, manufacturing and green initiatives, and are eager to pursue environmentally friendly products with longer service life and lower environmental impact.

[0003] The material used for sofa decoration is in close contact with the human body, and among them, suede leather has a skin feel and a non-cool tactile effect, becoming a mainstream sofa decoration leather product.

[0004] Patent No. 201410295312.X discloses a suede finishing agent and a preparation method thereof, which realizes suede effect through extinction powder, glass beads and silicone oil. However, this effect is not wear-resistant and not durable, and can only be obtained by post-processing.

[0005] Patent No. 201911049315.4 discloses a water-based foaming suede solvent-free composite polyurethane synthetic leather for sofas and a preparation method thereof. The suede effect is achieved by foaming the suede leather resin with suede powder at high temperature. However, this suede effect is rough in hand feel and cannot be maintained after wear-resistant treatment.

[0006] Therefore, it is necessary to develop a water-based and environmentally friendly suede material for synthetic leather to solve the current unqualified phenomena of poor leveling, shrinkage, bright spots, poor wear resistance, etc. of suede leather materials. SUMMARY

[0007] In view of the above problems existing in the prior art, the present application provides a water-based suede top layer composition for synthetic leather and a preparation method thereof. In the aliphatic water-based polyurethane dispersion, polystyrene microspheres and silicone rubber powder are used in combination to solve the unqualified phenomena of poor leveling, shrinkage, bright spots, poor wear resistance, etc. of suede leather materials. The leather material prepared from the suede top layer has good skin feel and good skin feel, and can meet the physical property requirements of sofa leather and the like.

[0008] To achieve the above technical effects, the technical scheme adopted by the present application is as follows:

[0009] In one aspect, the present application provides a water-based suede coating composition for synthetic leather, which is prepared from the following components by weight:

[0010]

[0011]

[0012] As a preferred, the water-based suede coating composition for synthetic leather is prepared from the following components by weight:

[0013]

[0014] In one specific example of the present application, the aliphatic water-based polyurethane dispersion has an acid value of 20-50 mgKOH / g, such as 20, 30, 40, 50 mgKOH / g, a particle size of 100-400 nm, such as 100, 200, 300, 400 nm, and a solid content of 35-45 wt%, such as 35, 40, 45 wt%.

[0015] The aliphatic water-based polyurethane dispersion meeting the above requirements of the present application has been reported in the prior art, and can be directly purchased or prepared by any method, and the present application does not have special requirements for its source. For example, as a preferred, the aliphatic water-based polyurethane dispersion can be a commercially available product such as Wanhua Chemical 3375、 3257, etc.

[0016] The aliphatic water-based polyurethane dispersion described in the present application can also be prepared by existing methods, and can generally be prepared by reacting a polyol with an aliphatic isocyanate. For example, patent CN109232851A provides a detailed description of a method for preparing an aliphatic water-based polyurethane dispersion. Based on these existing researches, the present application finds a preferred scheme for preparing the above-mentioned aliphatic water-based polyurethane dispersion. This method is only used to illustrate one of the methods used by the present application to prepare the aliphatic water-based polyurethane dispersion, but the source of raw materials of the aliphatic water-based polyurethane dispersion described in the present application should not be limited by the steps, raw materials, parameters, etc. in this method. In one preferred example of the present application, the aliphatic water-based polyurethane dispersion is prepared by the following steps:

[0017] 1) Put the reactive polyol, aliphatic isocyanate, hydrophilic group-containing compound, small molecule diol, catalyst, and first part of organic solvent into a reaction kettle protected by nitrogen, and heat to react;

[0018] 2) adding a second portion of organic solvent to dilute and cool, adding chain extender and end-capping agent to perform chain extension reaction, then adding neutralizer to perform neutralization reaction, adding water to perform shearing dispersion, and finally increasing temperature to remove organic solvent, to obtain the aliphatic waterborne polyurethane dispersion.

[0019] In one specific example, the mass parts of each raw material include: 100-200 parts, for example 100, 120, 140, 160, 180, 200 parts, of reactive polyol, 30-60 parts, for example 30, 40, 50, 60 parts, of aliphatic isocyanate, 100-300 parts, for example 100, 150, 200, 250, 300 parts, of organic solvent, 20-50 parts, for example 20, 30, 40, 50 parts, of hydrophilic group-containing compound, 1-5.5 parts, for example 1.0, 2.0, 3.0, 4.0, 5.0 parts, of small molecule diol, 10-30 parts, for example 10, 15, 20, 25, 30 parts, of post-chain extender, 10-30 parts, for example 10, 15, 20, 25, 30 parts, of end-capping agent, and 10-30 parts, for example 10, 15, 20, 25, 30 parts, of neutralizer; preferably, 120-180 parts of reactive polyol, 40-60 parts of aliphatic isocyanate, 150-250 parts of organic solvent, 25-40 parts of hydrophilic group-containing compound, 1.5-3.5 parts of small molecule diol, 14-22 parts of post-chain extender, 15-25 parts of end-capping agent, and 15-25 parts of neutralizer.

[0020] Preferably, the amount of catalyst used is 0.05-0.5wt%, for example 0.05, 0.1, 0.2, 0.3, 0.4, 0.5wt%, based on the total mass of reactants, wherein the reactants include reactive polyol, aliphatic isocyanate, hydrophilic group-containing compound, and small molecule diol.

[0021] In one specific example, the first portion of organic solvent is added in an amount of 5-30wt%, for example 5, 10, 20, 30wt%, and the second portion of organic solvent is added in an amount of 60-90wt%, for example 60, 70, 80, 90wt%, based on the total mass of reactants, wherein the reactants include reactive polyol, aliphatic isocyanate, hydrophilic group-containing compound, and small molecule diol.

[0022] In one specific example, the organic solvent is selected from ketone solvents, preferably one or more of acetone and butanone.

[0023] In one specific example, the aliphatic isocyanate is selected from one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI), butylene diisocyanate (BDI), 2,2,4-trimethylhexamethylene diisocyanate, diisocyanatomethylcyclohexane, diisocyanatomethyltricyclodecane, preferably one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI), more preferably isophorone diisocyanate (IPDI). The use of aliphatic isocyanate can effectively control the side reaction, and the film is permeable, resistant to yellowing, and can be used for the top layer of black and colored suede leather to exhibit black mist color effect.

[0024] In one specific example, the reactive polyol has a number average molecular weight of 600-4000, preferably a polycarbonate polyol having a number average molecular weight of 1000-2000; preferably, the polycarbonate polyol is selected from one or more of polyhexamethylene carbonate diol, poly-1,6-hexanediol carbonate diol, polycaprolactone hexamethylene carbonate diol, poly-1,4-butanediol-1,6-hexanediol carbonate diol, polypropylene carbonate diol, polyethylene carbonate diol, poly-1,5-pentanediol-1,6-hexanediol carbonate diol, polybutylene carbonate diol, polycyclohexanedimethanol-1,6-hexanediol carbonate diol, more preferably one or more of poly-1,6-hexanediol carbonate diol (such as Asahi Kasei 980r), poly-1,4-butanediol-1,6-hexanediol carbonate diol (such as Asahi Kasei GE502), and poly-1,5-pentanediol-1,6-hexanediol carbonate diol (such as Asahi Kasei T5652). The use of polycarbonate polyol can enable the top layer to have a lower modulus, ensure good suede skin feel effect, and not be sticky, thereby meeting the performance requirements of sofa leather, decorative leather, and the like, such as wear resistance, alcohol rubbing resistance, jungle resistance, and low temperature bending resistance.

[0025] In one specific example, the small molecule diol is selected from one or more of diethylene glycol, ethylene glycol, 1,4-butanediol, neopentyl glycol, and hexanediol, preferably one or more of diethylene glycol, 1,4-butanediol, and ethylene glycol, more preferably diethylene glycol and / or 1,4-butanediol.

[0026] In one specific example, the hydrophilic group-containing compound is a carboxyl-containing compound, preferably one or more of dimethylol propanoic acid, dimethylol butanoic acid, dimethylol acetic acid, and dihydroxy succinic acid, more preferably dimethylol propanoic acid.

[0027] In one specific example, the catalyst is selected from one or more of the group consisting of organic tin and / or organic bismuth, preferably dibutyltin dilaurate (T-12), stannous octoate (T-9), Coscat 83, organic bismuth 2811, organic bismuth 2808, organic bismuth 2010; wherein the organic tin is a more efficient catalyst and the organic bismuth is an environmentally friendly catalyst.

[0028] In one specific example, the post-chain extender is a small molecule organic amine compound selected from one or more of the group consisting of isophorone diamine, N-(2- hydroxyethyl) ethylene diamine and ethylene diamine, preferably N-(2-hydroxyethyl) ethylene diamine. The napped surface layer is applied to the variety of sofa upholstery leather, which basically adopts the process of water-based surface layer matched with solvent-free AB material foaming, and the NCO in the AB material foaming is excessive, and the small molecule organic amine compound, especially N-(2-hydroxyethyl) ethylene diamine, is used as the post-chain extender, which contains hydroxyl groups that can help the solvent-free AB material and the water-based surface layer to adhere firmly and establish excellent and lasting performance.

[0029] In one specific example, the capping agent is a hydroxyl-containing compound selected from one or more of the group consisting of 2-amino-2-methyl-1-propanol and 2,2'-dihydroxydiethylamine, preferably 2,2'-dihydroxydiethylamine.

[0030] In one specific example, the neutralizing agent is selected from one or more of the group consisting of diethanolamine and triethanolamine, preferably triethanolamine, wherein the amino group can react with the residual NCO in the prepolymer to perform capping, so that the molecular weight of the polyurethane is controlled within a certain range. If the molecular weight is too large, the napped release paper surface layer cannot be effectively fused and penetrated to the bottom of the groove, and if the molecular weight is too small, the basic wear resistance and dryness of the synthetic leather surface layer are affected. In addition, the hydroxyl groups in the capping agent, such as 2,2'-dihydroxydiethylamine, and the neutralizing agent, such as triethanolamine, can further strengthen the adhesion of the solvent-free AB material to the water-based surface layer.

[0031] In one specific example, the reaction in step 1) is carried out at a temperature of 70-90°C, such as 70, 80, 90°C, preferably 70-80°C, for a time of 2-7h, such as 2, 4, 6h, preferably 2-5h.

[0032] Preferably, the reaction is terminated when the theoretical NCO% value is reached, for example, the reaction is terminated when the NCO% is less than 3.5%, such as 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5%, preferably 2.5-3.5%.

[0033] In one specific example, the chain extension reaction of step 2) has a time of 5-50 min, for example 5, 10, 30, 50 min, preferably 10-30 min; the neutralization reaction has no particular limitation on time, for example it can be 1-30 min, preferably 15 min.

[0034] The reaction involved in step 2) includes a chain extension reaction by adding a chain extender and a blocking agent, and a neutralization reaction by adding a neutralizer, and neither of them has a particular limitation on temperature, for example it can be carried out at a temperature reached by dilution with a second portion of organic solvent to reduce the temperature, and the temperature reached by the dilution to reduce the temperature is 25-50°C, for example 25, 35, 45°C, preferably 30-40°C.

[0035] In one specific example, the water is preferably deionized water, and the amount of water added should be such that the solid content of the aliphatic aqueous polyurethane dispersion is 35-45 wt%, preferably 38-42 wt%.

[0036] In one specific example, the shear dispersion, preferably high-speed shear dispersion, has a speed of 1000-2500 rpm, for example 1000, 1500, 2000, 2500 rpm; the shear dispersion has no particular limitation on time, for example it can be 5-60 min, preferably 10-30 min, most preferably about 15 min. The aliphatic aqueous polyurethane dispersion prepared by the above-mentioned method of the present application has an acid value of 20-50 mgKOH / g, a particle size of 100-400 nm, and a solid content of 35-45 wt%, meeting the physical property requirements of the aliphatic aqueous polyurethane dispersion in the composition of the present application.

[0037] In one specific example of the present application, the polystyrene microspheres have a particle size of 1-100 μm, for example 1, 10, 30, 50, 70, 90, 100 μm, preferably 5-60 μm; preferably, the polystyrene microspheres are selected from one or more of the PST-1-100 series of Zhikemeng and the PS1500-10000 series of Suzhou Zhimicro-nano Technology.

[0038] In one specific example of the present application, the silicone rubber powder has a particle size of 1-100 μm, for example 1, 10, 30, 50, 70, 90, 100 μm, preferably 1-30 μm; preferably, the silicone rubber powder is selected from one or more of 9953, 2112 of Guangzhou Sloc, and SMP-594 of Japan Shin-Etsu.

[0039] In one specific example of the present application, the crosslinking agent is selected from one or more of aziridine crosslinking agents, carbodiimide crosslinking agents, and isocyanate crosslinking agents; preferably, the crosslinking agent is selected from CA01 of Shanghai Langyi.

[0040] In one specific example of the present application, the defoaming agent is selected from one or more of the group consisting of silicone-based defoaming agents, mineral oil-based defoaming agents, polyether polyol-based defoaming agents; preferably, the defoaming agent is selected from one or more of the group consisting of Evonik's PD-110, BASF's 2360.

[0041] In one specific example of the present application, the wetting agent is selected from one or more of the group consisting of acetylene diol-based wetting agents; preferably, the wetting agent is selected from one or more of the group consisting of Air Chemical's 104E, Kem-chem's DF804.

[0042] In one specific example of the present application, the hand agent is selected from one or more of the group consisting of polyether-modified silicone-based, polyether-emulsified silicone-based; preferably, the hand agent is selected from one or more of the group consisting of Silok Chemical's Silok 9155, Silok 3300.

[0043] In one specific example of the present application, the stabilizer is selected from one or more of the group consisting of bentonite series; preferably, the stabilizer is selected from one or more of the group consisting of Rockwood's Laponite RD, RDS.

[0044] In another aspect, the present application also provides a method for preparing the above-mentioned aqueous napped surface layer composition for synthetic leather, which can be prepared by means of conventional techniques in the art, such as blending.

[0045] The following only provides one exemplary method for preparation, but should not constitute any limitation on the method for preparing the composition of the present application.

[0046] A method for preparing an aqueous napped surface layer composition for synthetic leather, comprising the following steps: under stirring conditions, adding a wetting agent, a defoaming agent, a crosslinking agent, a hand agent, polystyrene microspheres, and silicone rubber powder into an aliphatic aqueous polyurethane dispersion, then adding a stabilizer to reach a viscosity of 3000-8000 cps, to obtain the aqueous napped surface layer composition for synthetic leather.

[0047] In one preferred example of the present application, the raw materials are added in groups, first adding a wetting agent, a defoaming agent, and a hand agent into an aliphatic aqueous polyurethane dispersion, stirring for a period of time, for example 30-60 min, then adding polystyrene microspheres and silicone rubber powder, stirring for a period of time, for example 30-60 min, then adding a crosslinking agent, stirring for a period of time, for example 5-10 min, and finally adding a stabilizer, stirring for a period of time, for example 10-30 min.

[0048] In addition, in the above-mentioned method for preparation, any step not specifically mentioned in the present application can be referred to the prior art.

[0049] In still another aspect, the synthetic leather water-based suede surface layer composition of the present application is widely used in the fields of clothing, luggage, shoes, household products, decorative products, automotive products, and the like, and is preferably used in sofa leather and decorative leather.

[0050] Compared with the prior art, the technical scheme of the present application has the beneficial effects that:

[0051] (1) The polystyrene microspheres and silicone rubber powder are used in the composition of the present application in synergy, so that the comfortable effect close to the skin touch can be obtained.

[0052] (2) In the composition of the present application, by matching the aliphatic water-based polyurethane dispersion and the stabilizer, during the drying process on the release paper, as the water is fixedly volatilized, the polystyrene microspheres and the silicone rubber powder can be partially exposed, and in the late drying period, through the melting and cold shrinkage of the polyurethane resin, the convex-concave design purpose of the surface microstructure can be achieved, and the polyurethane suede surface layer is obtained.

[0053] (3) In the composition of the present application, the water-based surface layer and the solvent-free AB material can be effectively and firmly adhered by the aliphatic water-based polyurethane dispersion. The polystyrene microspheres, especially the PST series microspheres, and the silicone rubber powder, such as 9946, have carboxyl active groups, which are crosslinked with the polyurethane under the action of the crosslinking agent, so as to further firmly combine the microspheres and the polyurethane main body resin, and even after wear and tear, the touch style effect can still be maintained.

[0054] (4) The composition material of the present application has good leveling property, and the suede surface layer does not have shrinkage holes, bright spots, and the like, so that the technical problem in the preparation of the suede surface layer in the water-based synthetic leather industry is solved. The leather material prepared from the suede surface layer has the advantages of good skin feeling and good skin adhesion, and has good resistance to bending, abrasion, alcohol wiping, and jungle testing, and can meet the physical property requirements in the fields of sofa leather and the like. BRIEF DESCRIPTION OF DRAWINGS

[0055] Figures 1-5 are respectively the convex-concave surface effect diagrams of the synthetic leather water-based polyurethane suede surface layer compositions prepared in Examples 1-5;

[0056] Figures 6-13 are respectively the surface effect diagrams of the water-based polyurethane surface layer compositions prepared in Comparative Examples 1-8. DETAILED DESCRIPTION

[0057] The embodiments of the present application are further illustrated below in conjunction with examples, but the present application is not limited to the listed examples, and any other known changes within the scope of the rights required by the present application should also be included.

[0058] The main raw material source information in the examples and comparative examples of the present application is as follows, and other raw materials are obtained from ordinary commercial channels unless otherwise specified:

[0059] Poly-1,4-butanediol-1,6-hexanediol carbonate diol: Asahi Kasei, GE502, Mn=2000;

[0060] Poly-1,6-hexanediol carbonate diol: Asahi Kasei, S6002, Mn=2000;

[0061] Poly-1,5-pentanediol-1,6-hexanediol carbonate diol: Asahi Kasei, T5652, Mn=2000;

[0062] IPDI: Wanhua Chemical;

[0063] HMDI: Wanhua Chemical;

[0064] HDI: Wanhua Chemical;

[0065] Dimethylol propionic acid: Shilong Industry;

[0066] Neopentyl glycol: Wanhua Chemical;

[0067] 1,4-Butanediol: Wanhua Chemical;

[0068] Organic bismuth 2010: American Leading Chemical;

[0069] Organic bismuth 2811: Leading Chemical;

[0070] Organic bismuth 2808: Leading Chemical;

[0071] Acetone: National Pharmaceutical Group;

[0072] AMP95: 5% water-containing-2-amino-2-methyl-1-propanol, Dow Chemical;

[0073] N-(2-hydroxyethyl) ethylene diamine: National Pharmaceutical Group;

[0074] Triethanolamine: National Pharmaceutical Group;

[0075] Triethylamine: National Pharmaceutical Group.

[0076] Preparation examples 1-4: Aliphatic aqueous polyurethane dispersions ①-④

[0077] The aliphatic aqueous polyurethane dispersions ①-④ were prepared according to the proportions shown in Table 1 (the amount of each component in the table is expressed in g, and the number in the parentheses is expressed in mol), and the preparation process included:

[0078] 1) The dehydrated reactants polyol, aliphatic isocyanate, hydrophilic group containing compound, small molecule diol, catalyst, and first portion of organic solvent (amount noted as 1) were added to a 1 L four-necked round bottom flask equipped with a nitrogen inlet and outlet. The mixture was stirred and warmed to react for 1 hour until the NCO % reached below the theoretical value;

[0079] 2) The second portion of organic solvent (amount noted as 2) was added to dilute the mixture and cool to 40 °C. Then, the temperature was maintained at 40 °C and the chain extender and capping agent were added to react for about 10-30 minutes. Then, the neutralizer was added to react for about 5 minutes. Deionized water was added and dispersed at a speed of 1000-2500 rpm for 10 minutes. Finally, the organic solvent was removed by distillation to obtain the aqueous polyurethane dispersion ①-④, whose acid value, particle size, and solid content are shown in Table 2.

[0080] Table 1. Preparation Example 1-4: Ratio and preparation conditions

[0081]

[0082]

[0083] Table 2. Acid value, particle size, and solid content of aliphatic aqueous polyurethane dispersion ①-④

[0084]

[0085]

[0086] Examples 1-5

[0087] The aqueous polyurethane suede coating composition for synthetic leather of Examples 1-5 was prepared according to the ratio shown in Table 3 (the amount of each component in the table is expressed in parts by weight), and the preparation process included:

[0088] The aliphatic aqueous polyurethane dispersion was weighed according to the formula and added to a stirred tank. Wetting agent, defoaming agent, and hand feel agent were added at a speed of 800 rpm and stirred for 10 minutes. Polystyrene microspheres and silicone rubber powder were added and stirred for 5 minutes. Crosslinking agent was added and stirred for 3 minutes. Finally, stabilizer was added and stirred for 5 minutes to adjust the viscosity to the appropriate value to obtain the aqueous suede coating slurry composition for synthetic leather.

[0089] Table 3. Ratio and preparation conditions of Examples 1-5

[0090]

[0091]

[0092] Comparative Example 1

[0093] The raw materials and the ratio of the waterborne polyurethane topcoat composition were prepared according to the preparation method of Example 1, except that no polystyrene microspheres PST-5 and silicone rubber powder 2112 were added, and other operations and parameters were unchanged, to obtain the waterborne polyurethane topcoat composition.

[0094] Comparative Example 2

[0095] The raw materials and the ratio of the waterborne polyurethane topcoat composition were prepared according to the preparation method of Example 1, except that the amount of polystyrene microspheres PST-5 was increased to 60 parts, and the amount of silicone rubber powder 2112 was increased to 30 parts, and other operations and parameters were unchanged, to obtain the waterborne polyurethane topcoat composition.

[0096] Comparative Example 3

[0097] The raw materials and the ratio of the waterborne polyurethane topcoat composition were prepared according to the preparation method of Example 1, except that all the stabilizer RD was replaced by 1.6 parts of thickening agent Wanhua U605, and other operations and parameters were unchanged, to obtain the waterborne polyurethane topcoat composition.

[0098] Comparative Example 4

[0099] The raw materials and the ratio of the waterborne polyurethane topcoat composition were prepared according to the preparation method of Example 1, except that no polystyrene microspheres PST-5 were added, and other operations and parameters were unchanged, to obtain the waterborne polyurethane topcoat composition.

[0100] Comparative Example 5

[0101] The raw materials and the ratio of the waterborne polyurethane topcoat composition were prepared according to the preparation method of Example 1, except that the polystyrene microspheres PST-5 were replaced by an equal amount of 1250 mesh kaolin filler, and other operations and parameters were unchanged, to obtain the waterborne polyurethane topcoat composition.

[0102] Comparative Example 6

[0103] The raw materials and the ratio of the waterborne polyurethane topcoat composition were prepared according to the preparation method of Example 1, except that no silicone rubber powder 2112 was added, and other operations and parameters were unchanged, to obtain the waterborne polyurethane topcoat composition.

[0104] Comparative Example 7

[0105] The raw materials and the ratio of the waterborne polyurethane topcoat composition were prepared according to the preparation method of Example 1, except that the silicone rubber powder 2112 was replaced by an equal amount of 325 mesh fiber powder, and other operations and parameters were unchanged, to obtain the waterborne polyurethane topcoat composition.

[0106] Comparative Example 8

[0107] The raw materials and the ratio of the waterborne polyurethane topcoat composition were prepared according to the preparation method of Example 1, except that the aliphatic waterborne polyurethane dispersion ① was replaced by an equal amount of Wanhua Chemical 3966 (TDI and ppg 2000 system, solid content: 35%, particle size: 115 nm), other operations and parameters unchanged, to prepare the waterborne polyurethane topcoat composition.

[0108] The waterborne polyurethane topcoat compositions of Examples 1-5 and Comparative Examples 1-8 above were used to prepare polyurethane topcoats according to the following method:

[0109] The waterborne polyurethane topcoat compositions were drawn on the suede release paper with a draw thickness of 0.12 mm, and dried at a temperature set according to a 90-110-125 degree stepwise increasing schedule, and after the release paper was separated, a conventional solvent-free AB material for sofa leather was drawn on the back, and a sofa leather was attached, and after drying, a

[0110] Figures 1-5 The convex-concave surface effect diagrams formed by the waterborne polyurethane suede topcoat compositions for synthetic leather prepared in Examples 1-5, respectively, can be seen that:

[0111] Example Figures 1-5 The convex feeling is stronger, wherein, Figure 2 Because there are more large balls, the display is larger, and the hand feeling is stronger, Figure 5 The microspheres are small, and are more wrapped by resin around, and the hand feeling is relatively weak.

[0112] Comparative Example Figures 6-13 Wherein, Figure 6 It can be seen that the surface has no roughness, and the suede effect of the leather surface is weak; Figure 7 It can be seen that the surface roughness is good, but other properties are worse, and cannot meet the use requirements; Figure 8 、 Figure 9 、 Figure 11 and Figure 13 It can be seen that the surface roughness is relatively weak, and the suede of the leather is weak; Figure 10 and Figure 12 It can be seen that the surface lacks roughness, and the suede of the leather is weak.

[0113] The polyurethane topcoats prepared in the above examples and comparative examples were respectively tested for performance, and the test results are shown in Table 4.

[0114] Table 4 Test results of polyurethane topcoat performance

[0115]

[0116]

[0117] The test method is as follows:

[0118] Surface effect: whether there are bright spots, white spots and other defect abnormalities is observed by a professional under a standard light box light source.

[0119] The pile feeling scoring method is that a professional compares and scores by hand touch, and is divided into 6 levels, namely 0, 1, 2, 3, 4 and 5, wherein 5 is the best.

[0120] The bending test method is that 3 pieces of warp and weft are respectively cut, bending tests are respectively conducted at normal temperature and low temperature, the bending times are recorded, and whether there is a crack is observed.

[0121] The abrasion resistance test method is that 3 pieces of warp and weft are respectively cut, the surface change of the tested sample is observed after the test, and the sample is judged as unqualified when the size exceeds that of a green bean, the times reached by each sample are recorded, the maximum and minimum values are removed, and the average abrasion resistance times are recorded.

[0122] The alcohol rubbing resistance test method is that a dry-wet rubbing color fastness instrument is used, 95% ethanol is used, and the surface is observed after back-and-forth rubbing 20 times, and there are 5 scoring standards from bad to good, namely 1, 2, 3, 4 and 5.

[0123] The above description is only the preferred embodiment of the present application, and is not any form and substantial limitation of the present application. It should be noted that, for ordinary skilled persons in the art, some improvements and supplements can be made without departing from the method of the present application, and these improvements and supplements should be regarded as the protection range of the present application. For those skilled in the art, some slight changes, modifications and equivalent changes made by using the disclosed technical content without departing from the spirit and scope of the present application are equivalent embodiments of the present application; meanwhile, any equivalent change, modification and evolution made according to the essential technology of the present application to the above embodiments are still within the range of the technical solution of the present application.

Claims

1. A water-based suede finish composition for synthetic leather, characterized by, Prepared from the following components by weight parts: The isocyanate used in the preparation of the aqueous polyurethane dispersion is selected from one or more of hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, butylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, bis-isocyanatomethylcyclohexane, bis-isocyanatomethyltricyclodecane; The reactive polyol used in the preparation of the aqueous polyurethane dispersion is a polycarbonate polyol.

2. The aqueous suede finish composition for synthetic leather according to claim 1, characterized by, Prepared from the following components by weight parts:

3. The aqueous suede finish composition for synthetic leather according to claim 1, characterized by, The aqueous polyurethane dispersion has an acid value of 20-50 mgKOH / g, a particle size of 100-400 nm, and a solid content of 35-45 wt%.

4. The aqueous suede finish composition for synthetic leather according to claim 1, characterized by, The aqueous polyurethane dispersion is prepared by the following steps: 1) The reactive polyol, isocyanate, carboxyl-containing compound, small molecule diol, catalyst, and first portion of organic solvent are added to a reaction kettle under nitrogen protection, heated and reacted; 2) The second portion of organic solvent is added to dilute and cool, the post-chain extender and capping agent are added for chain extension reaction, then the neutralizing agent is added for neutralization reaction, water is added for shearing dispersion, and finally the organic solvent is removed by heating to obtain the aliphatic aqueous polyurethane dispersion.

5. The aqueous nubuck coating composition for synthetic leather according to claim 4, characterized by, The raw material mass parts composition includes: reactive polyol 100-200 parts, isocyanate 30-60 parts, organic solvent 100-300 parts, carboxyl-containing compound 20-50 parts, small molecule diol 1-5.5 parts, post-chain extender 10-30 parts, capping agent 10-30 parts, neutralizing agent 10-30 parts.

6. The aqueous nubuck coating composition for synthetic leather according to claim 5, characterized by, The raw material mass parts composition includes: reactive polyol 120-180 parts, isocyanate 40-60 parts, organic solvent 150-250 parts, carboxyl-containing compound 25-40 parts, small molecule diol 1.5-3.5 parts, post-chain extender 14-22 parts, capping agent 15-25 parts, neutralizing agent 15-25 parts.

7. The aqueous suede finish composition for synthetic leather according to claim 4, characterized by The amount of the catalyst is 0.05-0.5 wt% based on the total mass of the reactants, wherein the reactants include the reactive polyol, isocyanate, carboxyl-containing compound, and small molecule diol.

8. The aqueous suede finish composition for synthetic leather according to claim 4, characterized by, The first portion of organic solvent is added in an amount of 5-30 wt% based on the total mass of the reactants, and the second portion of organic solvent is added in an amount of 60-90 wt% based on the total mass of the reactants, wherein the reactants include the reactive polyol, isocyanate, carboxyl-containing compound, and small molecule diol; and / or The organic solvent is selected from ketone solvents; and / or The reactive polyol is a polycarbonate polyol with a number average molecular weight of 600-4000; and / or The small molecule diol is selected from one or more of diethylene glycol, ethylene glycol, 1,4-butanediol, neopentyl glycol, and hexanediol; and / or The carboxyl-containing compound is one or more of dimethylol propanoic acid, dimethylol butanoic acid, dimethylol acetic acid, and dihydroxy succinic acid; and / or The catalyst is selected from organotin and / or organobismuth; and / or The post-chain extender is a small molecule organic amine compound; and / or The capping agent is a compound containing a hydroxyl group; and / or The neutralizing agent is selected from one or more of diethanolamine, triethanolamine.

9. The aqueous nubuck coating composition for synthetic leather according to claim 8, characterized by, The organic solvent is selected from one or more of acetone, butanone.

10. The aqueous nubuck coating composition for synthetic leather according to claim 8, characterized by, The reactive polyol is a polycarbonate polyol with a number average molecular weight of 1000-2000.

11. The aqueous suede finish composition for synthetic leather according to claim 8, characterized by, The small molecule diol is selected from one or more of diethylene glycol, 1,4-butanediol, ethylene glycol.

12. The aqueous suede finish composition for synthetic leather according to claim 8, characterized by, The post-chain extender is selected from one or more of isophorone diamine, N-(2-hydroxyethyl) ethylene diamine, and ethylene diamine.

13. The aqueous suede finish composition for synthetic leather according to claim 8, characterized by, The end-capping agent is selected from one or more of 2-amino-2-methyl-1-propanol, 2,2'-dihydroxydiethylamine.

14. The synthetic leather water-based suede coating composition according to claim 1, characterized in that, The polystyrene microspheres have a particle size of 1-100 μm.

15. The aqueous nubuck coating composition for synthetic leather according to claim 14, characterized by, The polystyrene microspheres have a particle size of 5-60 μm.

16. The synthetic leather water-based suede coating composition according to claim 1, characterized in that, The polystyrene microspheres are selected from one or more of the PST-1-100 series of Zhike Leiming, and the PS1500-10000 series of Suzhou Zhimian.

17. The synthetic leather water-based suede coating composition according to claim 1, characterized in that, The silicone rubber powder has a particle size of 1-100 μm.

18. The aqueous suede finish composition for synthetic leather according to claim 17, characterized by, The silicone rubber powder has a particle size of 1-30 μm.

19. The synthetic leather water-based suede coating composition according to claim 1, characterized in that, The silicone rubber powder is selected from one or more of 9953 and 2112 of Guangzhou Silokuo, and SMP-594 of Japan Shin Etsu.

20. The synthetic leather water-based suede coating composition of claim 1, wherein, The crosslinking agent is selected from one or more of aziridine crosslinking agents, carbodiimide crosslinking agents, and isocyanate crosslinking agents; and / or The defoaming agent is selected from one or more of silicone-based defoaming agents, mineral oil-based defoaming agents, and polyether polyol-based defoaming agents; and / or The wetting agent is selected from one or more of acetylenic diol-based wetting agents; and / or The hand agent is selected from one or more of polyether-modified silicone-based agents, and polyether-emulsified silicone-based agents. The stabilizer is selected from one or more of the bentonite series.

21. The aqueous pile coating composition for synthetic leather according to claim 20, characterized by, The crosslinking agent is CA01 of Shanghai Langyi.

22. The aqueous suede finish composition for synthetic leather according to claim 20, characterized by The defoaming agent is selected from one or more of PD-110 of Evonik, and 2360 of BASF.

23. The aqueous pile coating composition for synthetic leather according to claim 20, characterized by, The wetting agent is selected from one or more of 104E of Air Chemical, and DF804 of Cayman Chemical.

24. The aqueous pile coating composition for synthetic leather according to claim 20, characterized by, The hand agent is selected from one or more of Silok 9155 and Silok 3300 of Silok Chemical.

25. The aqueous pile coating composition for synthetic leather according to claim 20, characterized by, The stabilizer is selected from one or more of Laponite RD and RDS of Rockwood.

26. A method of preparing the aqueous napped topcoat composition for synthetic leather according to any one of claims 1 to 25, characterized by the steps of The method comprises: The wetting agent, the defoaming agent, the crosslinking agent, the hand agent, the polystyrene microspheres, and the silicone rubber powder are added to the aqueous polyurethane dispersion under stirring, and then the stabilizer is added to adjust the viscosity to 3000-8000 cps, to obtain the aqueous suede coating composition for synthetic leather.

27. The method of claim 26, wherein, Each raw material is added in groups. The wetting agent, the defoaming agent, and the hand agent are first added to the aqueous polyurethane dispersion, stirred for a period of time, and then the polystyrene microspheres and the silicone rubber powder are added and stirred for a period of time. Subsequently, the crosslinking agent is added and stirred for a period of time. Finally, the stabilizer is added and stirred for a period of time.

Images