Method for preparing waterborne polyurethane regenerated leather by wet method
Technical Field
The invention relates to the technical field of waterborne polyurethane reclaimed leather, and particularly discloses a method for preparing waterborne polyurethane reclaimed leather by a wet method.
Background
Synthetic leather has been applied to each field in people's life at present, and the variety is various. Synthetic leather has the characteristics of natural gloss, strong real leather feeling, excellent mechanical property and resistance and the like, is widely used in the industries of clothing, shoemaking, bags, furniture and the like, and has two production processes, namely a dry method and a wet method. The dry process is the earliest developed industrial process and features that solvent in solvent type polyurethane resin is volatilized in drying oven to form multilayer structure comprising multilayer film and base fabric. The wet process employs an in-water film formation process to obtain a multilayer structure having a continuous porous layer. The sofa leather has certain requirements on the mechanical strength and the hardness of the leather, so the sofa leather is generally prepared by a dry method.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a method for preparing the waterborne polyurethane regenerated leather by a wet method.
In order to achieve the above purpose, the invention is realized by the following technical scheme:
in a first aspect, the invention provides a method for preparing waterborne polyurethane reclaimed leather by a wet method, which comprises the following steps:
1) treating a base material: soaking the flocked bovine fiber base material by using an impregnation liquid in an impregnation tank, then coagulating by using a coagulation liquid in a coagulation tank, extruding by using a three-plate machine, and drying; 2) coating: coating the treated flocked bovine fiber substrate with foaming slurry; 3) and (3) agglomeration: coagulating the flocked bovine fiber base material coated with the foaming slurry through a coagulation liquid in a coagulation tank; 4) washing and drying: removing redundant condensed liquid through a water washing tank, and drying and shaping to obtain water-based regenerated Pibess; 5) dry-process veneering: coating aqueous surface layer slurry on release paper, drying, coating middle layer slurry for the second time, finally laminating by using the aqueous reclaimed leather base, drying, and stripping the release paper to obtain the aqueous polyurethane reclaimed leather.
Preferably, in the step 1), the impregnation liquid is composed of the following raw materials in parts by mass: 20-30 parts of anionic waterborne polyurethane resin with the solid content of 40-42%, 70-80 parts of tap water and 0.5-2 parts of penetrating agent.
Preferably, the penetrating agent is fatty alcohol-polyoxyethylene ether.
Preferably, in step 1) and step 3), the coagulation liquid is composed of the following raw materials and parts by mass thereof: 3-5 parts of a demulsifying crosslinking agent and 95-97 parts of tap water; the demulsifying crosslinking agent is any one or more of carbonic acid, lactic acid, citric acid, phosphoric acid, calcium chloride, ferric sulfate, sodium chloride, ferric chloride and aluminum chloride.
Preferably, in the step 2), the foaming slurry is composed of the following raw materials in parts by mass: 200 parts of anionic waterborne polyurethane resin with the solid content of 40-42%, 0.5-1 part of dispersing agent, 5-15 parts of lignocellulose, 1-5 parts of nano calcium carbonate, 2.5-10 parts of kaolin, 3-6 parts of foaming agent, 3-6 parts of foam stabilizer, 0.5-2 parts of curing agent, 0.5-0.8 part of powder thickener and the foaming multiplying power of 1.2-1.7 times; the viscosity of the foaming slurry is 20000-30000 mPa.s.
Preferably, the kaolin is kaolin powder with a mesh number greater than 1250. The mechanical strength and the compression resistance of the regenerated leather are improved by adding the kaolin.
Preferably, the foaming agent is an organic silicon modified foaming agent, a sodium dodecyl sulfate composite foaming agent or a stearate foaming agent.
Preferably, the foam stabilizer is a silicone polyether emulsion foam stabilizer.
Preferably, the curing agent is an aromatic amine curing agent, a modified amine curing agent or a sulfonic acid curing agent.
Preferably, the mesh number of the lignocellulose is 400-1000.
Preferably, the powder thickener is a cellulose-type thickener.
Preferably, in the step 2), the coating amount of the foaming slurry is 500-1000 g/m2。
Preferably, in the step 5), the aqueous surface layer slurry is composed of the following raw materials in parts by mass: 100 parts of aliphatic waterborne polyurethane with the solid content of 30-50%, 0.2-0.8 part of defoaming agent, 0.5-0.8 part of wetting agent, 2-5 parts of wear-resistant additive, 5-10 parts of nano calcium carbonate, 2-5 parts of wear-resistant wax powder and 0.2-2 parts of water-based thickener.
Preferably, the wear-resistant auxiliary is an organosilicon modified wear-resistant auxiliary.
Preferably, the aqueous thickener of the aqueous surface layer slurry is an associated polyurethane thickener or an alkali-swellable acrylic thickener.
Preferably, in the step 5), the coating amount of the aqueous surface layer slurry is 100-300 g/m2。
Preferably, in step 5), the middle layer slurry is composed of the following raw materials in parts by mass: 100 parts of aliphatic waterborne polyurethane with the solid content of 30-50%, 0.2-0.8 part of defoaming agent, 5-10 parts of nano calcium carbonate, 0.5-0.8 part of wetting agent and 0.2-2 parts of waterborne thickener, wherein the viscosity of the middle layer slurry is 5000-7000 mPa.s.
Preferably, the aqueous thickener of the aqueous surface layer sizing agent and the aqueous thickener of the middle layer sizing agent are associative polyurethane thickeners or alkali swelling acrylic acid thickeners.
Preferably, the defoaming agent of the aqueous surface layer slurry and the middle layer slurry is an organic silicon modified defoaming agent or a mineral oil-based defoaming agent.
Preferably, in the step 5), the coating amount of the middle layer slurry is 100-300 g/m each time2。
In a second aspect, the invention provides a waterborne polyurethane reclaimed leather, which is prepared by the method for preparing the waterborne polyurethane reclaimed leather by the wet method.
In a third aspect, the invention provides an application of the waterborne polyurethane reclaimed leather in preparing sofa leather.
In conclusion, the invention provides a method for preparing waterborne polyurethane reclaimed leather by a wet method, which has the beneficial effects that:
the invention adopts the aqueous polyurethane resin slurry and the aqueous environment-friendly auxiliary agent, so that the regenerated leather does not contain any organic solvent in the preparation and use processes, the problems of pollution and residue of solvent-type space leather are solved, and clean production is realized. Through the physical and chemical double foaming mode, the foam holes are uniform and stable, the obtained regenerated leather has good cuts, a fine and compact structure and low possibility of cracking and wearing. According to the invention, the flocked bovine fiber substrate and kaolin are adopted to endow the regenerated leather with excellent mechanical strength, and the nano calcium carbonate is added to ensure that the regenerated leather has good air permeability; the abrasion-resistant auxiliary agent and the abrasion-resistant wax powder are added into the water-based surface layer slurry, so that the scratch resistance and abrasion resistance of the surface of the regenerated leather are improved, the surface of the regenerated leather is smooth, and the hand feeling is good. The reclaimed leather obtained by the invention has good air permeability, high mechanical strength, high hardness and good smoothness, and is suitable for the field of sofa leather preparation.
Detailed Description
The invention is further illustrated by the following examples. It should be understood that the examples are for illustrative purposes only and are not intended to limit the scope of the present invention.
Example 1
A method for preparing waterborne polyurethane regenerated leather by a wet method comprises the following steps:
1. preparing materials:
1.1 preparation of impregnation liquid: 25kg of waterborne polyurethane resin KT735 (water-soluble in fertilizer family) with the solid content of 42 percent and 1.5kg of penetrant JFC are added into 75kg of tap water and stirred uniformly at high speed to obtain the impregnation liquid.
1.2 preparation of a coacervate: 3kg of calcium chloride and 97kg of tap water were mixed and stirred to completely dissolve the phosphoric acid in the water.
1.3, preparing foaming slurry: 200kg of waterborne polyurethane resin KT735 (combined fertilizer family waterborne) with the solid content of 42 percent is taken, 0.8kg of dispersing agent A168, 5kg of lignocellulose (Yixing Shengdeli), 3kg of nano calcium carbonate (Henan Keli new material), 5kg of 1250-mesh kaolin, 4.8kg of foaming agent K12 (Jinan Shuichang chemical industry), 4.8kg of foam stabilizer 207 (Qingdao Taobao chemical industry), 1.2kg of curing agent XP2655 (German Bayer) and 0.5kg of cellulose type thickening agent (Dezhouweisi) are sequentially added, and the mixture is stirred by a high-speed stirrer and foamed to 1.5 times of the original volume to obtain the foaming slurry.
1.4 preparing aqueous surface layer slurry: 100kg of aqueous polyurethane resin KT727 (combined fertilizer family natural water property) with the solid content of 30 percent is taken, 0.5kg of defoaming agent CF247 (Kelaien chemical industry), 0.6kg of wetting agent TEGO245, 2kg of wear-resistant additive DC51 (American Dow Corning), 6kg of nano calcium carbonate (Henan Korea new material), 5kg of wear-resistant wax powder E360 (Wengsheng) and 0.7kg of aqueous thickening agent 3220 (Shenzhen Haichuan chemical industry) are sequentially added, and the mixture is uniformly dispersed by a high-speed mixer with the viscosity of 2800 mPa.s, so that the aqueous surface layer slurry is obtained.
1.5 preparing middle layer slurry: 100kg of aliphatic waterborne polyurethane resin KT703B (Hefei Ketianshu) with solid content of 35 percent is taken, 0.4kg of defoaming agent CF247 (Kelaien chemical industry), 5kg of nano calcium carbonate (Henan Keli new material), 0.6kg of wetting agent TEGO270 and 0.5kg of waterborne thickener 3220 (Shenzhen Hehaichuan chemical industry) are sequentially added, and the mixture is uniformly dispersed by a high-speed stirrer with viscosity of 5800mPa · s, so that the middle layer slurry is obtained.
2. Preparing waterborne polyurethane space leather:
2.1 base fabric treatment: soaking the flocked bovine fiber base material by using a steeping liquor in a steeping trough, then coagulating by using a coagulating trough, extruding by using a three-plate machine, and drying by using a 130 ℃ oven.
2.2 coating: coating the treated flocked bovine fiber substrate with foaming slurry at 580g/m2。
2.3 agglomeration: coagulating the flocked bovine fiber base material coated with the foaming slurry through a coagulation liquid in a coagulation tank, demulsifying the aqueous polyurethane, forming a porous filler together with the lignocellulose, the kaolin and the nano calcium carbonate, and filling the porous filler into the flocked bovine fiber base material.
2.4 washing and drying: and (4) removing redundant condensed liquid through a water washing tank, and drying and shaping to obtain the water-based regenerated Pibess.
2.5 dry coating: coating the release paper with water-based surface layer sizing agent, wherein the coating amount is 220g/m2Oven drying at 110 deg.C, coating with middle layer slurry at coating amount of 200g/m2Oven drying at 130 deg.C, coating the intermediate layer slurry twice, the coating amount is 200g/m2And finally, adhering the waterborne recycled leather base, drying and stripping release paper to obtain the waterborne polyurethane recycled leather.
Example 2
A method for preparing waterborne polyurethane regenerated leather by a wet method comprises the following steps:
1. preparing materials:
1.1 preparation of impregnation liquid: 25kg of waterborne polyurethane resin KT735 (water-soluble in fertilizer family) with the solid content of 42 percent and 1.5kg of penetrant JFC are added into 75kg of tap water and stirred uniformly at high speed to obtain the impregnation liquid.
1.2 preparation of a coacervate: 3kg of lactic acid, 1kg of citric acid and 96kg of tap water were mixed and stirred to completely dissolve the lactic acid and the citric acid in the water.
1.3, preparing foaming slurry: 200kg of waterborne polyurethane resin KT735 (combined fertilizer family waterborne) with the solid content of 42 percent is taken, 1kg of dispersing agent A168, 7kg of lignocellulose (Yixing Shengdeli), 5kg of nano calcium carbonate (Henan Keli new material), 2.5kg of 1250-mesh kaolin, 3.5kg of foaming agent K12 (Jinan Shuichang chemical industry), 3.5kg of foam stabilizer 207 (Qingdao Bao chemical industry in Qingdao), 1kg of curing agent XP2655 (Germany Bayer) and 0.7kg of cellulose type thickening agent (Dezhouweisi) are sequentially added, stirred by a high-speed stirrer and foamed to 1.3 times of the original volume, and the foaming slurry is obtained.
1.4 preparing aqueous surface layer slurry: 100kg of aqueous polyurethane resin KT727 (Hefei Ke Tianshui) with solid content of 35 percent is taken, 0.8kg of defoaming agent CF247 (Kelaien chemical industry), 0.8kg of wetting agent TEGO245, 4kg of wear-resistant additive DC51 (American Dow Corning), 8kg of nano calcium carbonate (Henan Keli new material), 4kg of wear-resistant wax powder E360 (Wengshenkel) and 1.2kg of aqueous thickening agent 3220 (Shenzhen Haichuan chemical industry) are sequentially added, and the mixture is uniformly dispersed by a high-speed mixer with viscosity of 3500mPa s, so that the aqueous surface layer slurry is obtained.
1.5 preparing middle layer slurry: taking 100kg of aliphatic waterborne polyurethane resin KT703B (Hefei Ketianshu) with the solid content of 35%, sequentially adding 0.8kg of defoaming agent CF247 (Kelaien chemical industry), 7kg of nano calcium carbonate (Henan Keli new material), 0.5kg of wetting agent TEGO270 and 0.8kg of waterborne thickener 3220 (Shenzhen Heishuan chemical industry), uniformly dispersing by using a high-speed stirrer, and obtaining the middle layer slurry with the viscosity of 6200 mPa.
2. Preparing waterborne polyurethane space leather:
2.1 base fabric treatment: soaking the flocked bovine fiber base material by using a steeping liquor in a steeping trough, then coagulating by using a coagulating trough, extruding by using a three-plate machine, and drying by using a 120 ℃ oven.
2.2 coating: coating the treated flocked fibrous substrate with foaming slurry at the coating amount of 620g/m2。
2.3 agglomeration: coagulating the flocked bovine fiber base material coated with the foaming slurry through a coagulation liquid in a coagulation tank, demulsifying the aqueous polyurethane, forming a porous filler together with the lignocellulose, the kaolin and the nano calcium carbonate, and filling the porous filler into the flocked bovine fiber base material.
2.4 washing and drying: and (4) removing redundant condensed liquid through a water washing tank, and drying and shaping to obtain the water-based regenerated Pibess.
2.5 dry coating: coating the release paper with water-based surface layer sizing agent, wherein the coating amount is 220g/m2Oven drying at 120 deg.C, coating with middle layer slurry at coating amount of 200g/m2Oven drying at 120 deg.C, coating the middle layer slurry twice, with a coating amount of 200g/m2And finally, adhering the waterborne recycled leather base, drying and stripping release paper to obtain the waterborne polyurethane recycled leather.
Example 3
A method for preparing waterborne polyurethane regenerated leather by a wet method comprises the following steps:
1. preparing materials:
1.1 preparation of impregnation liquid: 25kg of waterborne polyurethane resin KT735 (water-based in fertilizer combining department) with the solid content of 42% and 2kg of penetrant JFC are added into 76kg of tap water, and the mixture is stirred uniformly at a high speed to obtain the impregnation liquid.
1.2 preparation of a coacervate: 3kg of ferric sulfate and 97kg of tap water were mixed and stirred to completely dissolve the ferric sulfate in the water.
1.3, preparing foaming slurry: 200kg of waterborne polyurethane resin KT735 (combined fertilizer family waterborne) with the solid content of 42 percent is taken, 0.5kg of dispersing agent A168, 10kg of lignocellulose (Yixing Shengdeli), 3kg of nano calcium carbonate (Henan Keli new material), 10kg of 1250-mesh kaolin, 4.8kg of foaming agent K12 (Jinan Shuichang chemical industry), 4.8kg of foam stabilizer 207 (Qingdao Taobao chemical industry), 1.2kg of curing agent XP2655 (German Bayer) and 0.5kg of cellulose type thickening agent (Dezhouweisi) are sequentially added, and the mixture is stirred by a high-speed stirrer and foamed to 1.5 times of the original volume to obtain the foaming slurry.
1.4 preparing aqueous surface layer slurry: 100kg of aqueous polyurethane resin KT727 (Hefei Ke Tianshui) with the solid content of 30 percent is taken, 0.3kg of defoaming agent CF247 (Kelaien chemical industry), 0.7kg of wetting agent TEGO245, 5kg of wear-resistant additive DC51 (American Dow Corning), 7kg of nano calcium carbonate (Henan Keli new material), 2kg of wear-resistant wax powder E360 (Wengsheng Ke Er) and 0.5kg of aqueous thickening agent 3220 (Shenzhen Haichuan chemical industry) are sequentially added, and the mixture is uniformly dispersed by a high-speed mixer with the viscosity of 2400mPa s, so that the aqueous surface layer slurry is obtained.
1.5 preparing middle layer slurry: 100kg of aliphatic waterborne polyurethane resin KT703B (Hefei Ketianshu) with solid content of 35 percent is taken, 0.4kg of defoaming agent CF247 (Kelaien chemical industry), 5kg of nano calcium carbonate (Henan Keli new material), 0.6kg of wetting agent TEGO270 and 0.6kg of waterborne thickener 3220 (Shenzhen Hehaichuan chemical industry) are sequentially added, and the mixture is uniformly dispersed by a high-speed stirrer with viscosity of 5800mPa · s, so that the middle layer slurry is obtained.
2. Preparing waterborne polyurethane space leather:
2.1 base fabric treatment: soaking the flocked bovine fiber base material by using a steeping liquor in a steeping trough, then coagulating by using a coagulating trough, extruding by using a three-plate machine, and drying by using a 120 ℃ oven.
2.2 coating: coating the treated flocked fibrous substrate with foaming slurry in the amount of 630g/m2。
2.3 agglomeration: coagulating the flocked bovine fiber base material coated with the foaming slurry through a coagulation liquid in a coagulation tank, demulsifying the aqueous polyurethane, forming a porous filler together with the lignocellulose, the kaolin and the nano calcium carbonate, and filling the porous filler into the flocked bovine fiber base material.
2.4 washing and drying: and (4) removing redundant condensed liquid through a water washing tank, and drying and shaping to obtain the water-based regenerated Pibess.
2.5 dry coating: coating aqueous surface layer sizing agent on release paper, wherein the coating amount is 200g/m2Oven drying at 100 deg.C, coating with middle layer slurry at a coating amount of 250g/m2Oven drying at 100 deg.C, coating the intermediate layer slurry twice with a coating amount of 150g/m2Finally useAnd (3) attaching the waterborne recycled leather base, drying and stripping the release paper to obtain the waterborne polyurethane recycled leather.
Example 4
A method for preparing waterborne polyurethane regenerated leather by a wet method comprises the following steps:
1. preparing materials:
1.1 preparation of impregnation liquid: 25kg of waterborne polyurethane resin KT735 (water-soluble in fertilizer family) with the solid content of 42 percent and 1.5kg of penetrant JFC are added into 75kg of tap water and stirred uniformly at high speed to obtain the impregnation liquid.
1.2 preparation of a coacervate: 5kg of aluminum chloride and 95kg of tap water were mixed and stirred to completely dissolve phosphoric acid in water.
1.3, preparing foaming slurry: 200kg of aqueous polyurethane resin KT735 (Hefei Keshui) with the solid content of 42 percent is taken, 1kg of dispersing agent A168, 9kg of lignocellulose (Yixing Shengdeli), 4kg of nano calcium carbonate (Henan Keli new material), 7.5kg of 1250-mesh kaolin, 5.2kg of foaming agent K12 (Jinan Shuichang chemical industry), 5kg of foam stabilizer 207 (Qingdao Taobao chemical industry), 1.2kg of curing agent XP2655 (German Bayer) and 0.5kg of cellulose type thickening agent (Dezhouweisi) are sequentially added, stirred by a high-speed stirrer and foamed to 1.7 times of the original volume, and the foaming slurry is obtained.
1.4 preparing aqueous surface layer slurry: 80kg of aqueous polyurethane resin KT727 (Hefei Ke Tianshui) with the solid content of 30 percent is taken, 0.7kg of defoaming agent CF247 (Kelaien chemical industry), 0.5kg of wetting agent TEGO245, 4kg of wear-resistant additive DC51 (American Dow Corning), 10kg of nano calcium carbonate (Henan Keli new material), 3kg of wear-resistant wax powder E360 (Wengsheng Ke Er) and 0.8kg of aqueous thickening agent 3220 (Shenzhen Haichuan chemical industry) are sequentially added, and the mixture is uniformly dispersed by a high-speed mixer with the viscosity of 2900mPa s, so that the aqueous surface layer slurry is obtained.
1.5 preparing middle layer slurry: 100kg of aliphatic waterborne polyurethane resin KT703B (Hefei Ketianshu) with solid content of 35 percent is taken, 0.4kg of defoaming agent CF247 (Kelaien chemical industry), 8kg of nano calcium carbonate (Henan Keli new material), 0.7kg of wetting agent TEGO270 and 0.6kg of waterborne thickener 3220 (Shenzhen Hehaichuan chemical industry) are sequentially added, and the mixture is uniformly dispersed by a high-speed stirrer with viscosity of 5800mPa · s, so that the middle layer slurry is obtained.
2. Preparing waterborne polyurethane space leather:
2.1 base fabric treatment: soaking the flocked bovine fiber base material by using a steeping liquor in a steeping trough, then coagulating by using a coagulating trough, extruding by using a three-plate machine, and drying by using a 120 ℃ oven.
2.2 coating: coating the treated flocked bovine fiber substrate with foaming slurry at 580g/m2。
2.3 agglomeration: coagulating the flocked bovine fiber base material coated with the foaming slurry through a coagulation liquid in a coagulation tank, demulsifying the aqueous polyurethane, forming a porous filler together with the lignocellulose, the kaolin and the nano calcium carbonate, and filling the porous filler into the flocked bovine fiber base material.
2.4 washing and drying: and (4) removing redundant condensed liquid through a water washing tank, and drying and shaping to obtain the water-based regenerated Pibess.
2.5 dry coating: coating the release paper with water-based surface layer sizing agent, wherein the coating amount is 220g/m2Oven drying at 140 deg.C, coating with middle layer slurry with coating amount of 220g/m2Oven drying at 140 deg.C, coating middle layer slurry twice with coating amount of 180g/m2And finally, adhering the waterborne recycled leather base, drying and stripping release paper to obtain the waterborne polyurethane recycled leather.
And (3) detection results: the performance of the waterborne polyurethane reclaimed leather prepared in the 4 examples is tested according to the national standard QBT 4712-2014 polyurethane synthetic leather for sofa, and the test results are shown in Table 1.
Table 1 results of measuring properties of the waterborne polyurethane reclaimed leather prepared in examples 1 to 4
As shown in table 1, the waterborne polyurethane recycled leather prepared in examples 1 to 4 has excellent flatness, and the peel strength is far greater than the national standard requirement, which indicates that the bonding performance of the recycled leather is good, and the waterborne polyurethane recycled leather has good wear resistance, and the waterborne polyurethane recycled leather prepared in examples 1 to 4 has high peel strength and wear resistance, smooth surface, good hand feeling, and improves the grade of sofa leather.
While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. Those skilled in the art can make various changes, modifications and equivalent arrangements, which are equivalent to the embodiments of the present invention, without departing from the spirit and scope of the present invention, and which may be made by utilizing the techniques disclosed above; meanwhile, any changes, modifications and variations of the above-described embodiments, which are equivalent to those of the technical spirit of the present invention, are within the scope of the technical solution of the present invention.