Environmentally friendly sea island water-based microfiber suede leather and its preparation process

Abstract

The present invention relates to the technical field of microfiber leather, and specifically to an environmentally friendly sea island water-based microfiber suede leather and a preparation process thereof, wherein the preparation process specifically comprises the following steps: S1, pretreatment of non-woven fabric; S2, preparation of multi-layer base fabric; S3, impregnation with aqueous polyurethane slurry; S4, curing; S5, hot water fiber opening; S6, kneading and grinding; in step S1, the island-type sea island fiber non-woven fabric is sequentially immersed in a dialdehyde-type oxidized sodium alginate aqueous solution and a dopamine buffer solution, followed by ultrasonic cross-linking, and then oven drying to obtain a dopamine-modified non-woven fabric, and a dopamine cross-linked film is generated on the surface of the island-type sea island fiber. The present invention adopts water medium in both the impregnation and fiber opening processes, and the production process is environmentally friendly; the water-based polyurethane slurry filling the microfiber gap is greatly reduced, the hot water fiber opening process is smooth and the release structure between the microfiber and the water-based polyurethane resin is maintained, which effectively improves the softness of the microfiber leather.

Description

Technical Field

[0001] The invention relates to the technical field of microfiber leather, and in particular to an environmentally friendly sea island water-based microfiber suede leather and a preparation process thereof. Background Art

[0002] The currently produced microfiber-based fabrics are divided into water-based microfiber-based fabrics and solvent-based microfiber-based fabrics. Compared with solvent-based microfiber-based fabrics, the preparation method of water-based microfiber-based fabrics is more environmentally friendly, and water is used instead of organic solvents, which greatly saves costs.

[0003] At present, most synthetic leathers on the market use solvent-based polyurethane, which has poor environmental protection and a large amount of organic solvent volatilization during the production process, which does not conform to the current trend of green environmental protection. Since water-based polyurethane uses water as the dispersion medium, there is no solvent volatilization during the production process, which does not pollute the environment and poses no health hazards to operators in the production workshop, making it more environmentally friendly and harmless. At the same time, there is no odor during the production process of water-based polyurethane, it is not easy to burn, and the processing process is safe and reliable. With the continuous improvement of people's quality of life, water-based polyurethane is increasingly used in the field of synthetic leather.

[0004] With the advancement of technology, water-soluble sea-island fibers with polyvinyl alcohol as the sea phase are now available on the market. They can be used as non-woven fabrics and can be opened with hot water. However, in order to increase the affinity with water, water-based polyurethane introduces a large number of hydrophilic groups into the molecular chain. These hydrophilic groups make the impregnated leather easy to swell due to hydrophilicity during the hot water opening process. During the hot water opening process, the sea phase in the sea-island fiber is continuously extracted, leaving pores. Under the action of the mechanical force of the roller and the heat of the solvent, the water-based polyurethane resin continuously fills the pores and adheres to the surface of the ultrafine fiber, causing the release structure between the ultrafine fiber and the polyurethane resin to be eventually destroyed, and it becomes even more compacted after the reduction is completed. Summary of the invention

[0005] The invention aims to provide an environmentally friendly sea island water-based microfiber suede leather and a preparation process thereof, which can greatly reduce the damage to the release structure between the microfiber and the resin and ensure high softness.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is:

[0007] The environmentally friendly sea island water-based microfiber suede leather preparation process specifically comprises the following steps:

[0008] S1. Pretreatment of nonwoven fabric: taking a fixed-island type sea-island fiber nonwoven fabric and immersing it in a dialdehyde type oxidized sodium alginate aqueous solution and a dopamine buffer solution in turn, then performing ultrasonic cross-linking, and then drying in an oven to obtain a dopamine modified nonwoven fabric, and forming a dopamine cross-linked film on the surface of the fixed-island type sea-island fiber; the sea component of the fixed-island type sea-island ultrafine fiber is a water-soluble polymer and the island component is a water-insoluble polymer;

[0009] S2, preparing a multi-layer base fabric: taking a water-based polyurethane mesh as an elastic middle layer and the dopamine-modified non-woven fabric of step S1 as an upper and lower interlayer, and compounding the three layers and needle-punching to form a multi-layer base fabric;

[0010] S3, impregnating with water-based polyurethane slurry: impregnating the multi-layer base fabric of step S2 with water-based polyurethane slurry, double dipping and double rolling, the room temperature viscosity is 2000mPa·s~2500mPa·s, and the liquid carrying rate is 150%-200%; the components of the polyurethane slurry are water-based polyurethane, water-soluble powder, defoamer, leveling agent, thickener and deionized water, and the solid content is 25%-30%;

[0011] S4, curing: firstly drying at a medium temperature of 85°C to 90°C until the water volatilization rate reaches 80%-85%, and then drying at a high temperature of 120°C to 135°C to obtain a microporous base semi-finished product;

[0012] S5. Hot water fiber opening: Use deionized water at a temperature of 75℃-95℃ as the medium for weight reduction treatment for 30min-50min, and then dry;

[0013] S6. Soften and grind the leather to obtain sea island water-based microfiber suede.

[0014] Preferably, the fineness of the island-in-the-sea fibers in step S1 is 1.5 dtex to 6.5 dtex, and the number of islands is 37.

[0015] Preferably, the sea component of the island-in-the-sea fibers in step S1 is water-soluble polyester WSPET, and the island components are PET or PA6.

[0016] Preferably, the acupuncture density in step S2 is 600 to 800 punctures / cm 2 , the weight of the multi-layer base fabric is 250g / m 2 ~450g / m 2 .

[0017] Preferably, the water-soluble powder is a water-soluble acrylic acid oligomer with a polymerization rate of 95%.

[0018] Preferably, the second rolling pressure in step S3 is 25kg / cm 2 ~30kg / cm 2 and 10kg / cm 2~12kg / cm 2 .

[0019] Preferably, the weight reduction treatment in step S5 is specifically as follows: the microporous bass semi-finished product of step S4 is sequentially immersed in different fiber opening grooves with increasing temperatures for hot water fiber opening, the water temperature increment is 5°C-10°C, the treatment time of each fiber opening groove is 10min±3min, and two immersion padding treatments are performed at the outlet of each fiber opening groove, and the pressure is 2kg / cm 2 ~4kg / cm 2 .

[0020] Preferably, the leather kneading and softening speed in step S6 is 4m / min-5m / min, and the temperature is set as follows: 95℃-100℃ in the first zone, 120℃-125℃ in the second zone, 120℃-125℃ in the third zone, 125℃-135℃ in the fourth zone, and 130℃-135℃ in the fifth zone.

[0021] Preferably, the leather grinding speed in step S6 is 4m / min-5m / min, the gap in the first zone is 0.6mm-1.2mm, and the sanding belt is 250-350 mesh; the gap in the second zone is 0.4mm-0.8mm, and the sanding belt is 350-500 mesh.

[0022] The present invention further provides an environmentally friendly sea island water-based microfiber suede leather prepared by the above-mentioned preparation process.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The preparation process of the sea island water-based microfiber suede leather of the present invention comprises pretreatment of non-woven fabric, preparation of multi-layer base fabric, impregnation and curing, and hot water fiber opening. Water medium is used in both the impregnation and fiber opening processes, and the production process is environmentally friendly.

[0025] The present invention performs surface modification on the fixed-island fiber of the non-woven fabric before impregnation, and sequentially coats it with dialdehyde-type oxidized sodium alginate and dopamine, realizes the amino cross-linking reaction of dialdehyde-type oxidized sodium alginate and dopamine by means of ultrasound to form a film, and coats it on the surface of the island fiber by means of the adhesion property of polydopamine to obtain a dopamine cross-linked film, which improves the mechanical properties of the dopamine cross-linked film on the one hand, and enhances the water resistance and integrity of the dopamine cross-linked film on the other hand, cooperates with the light pressure control of fiber opening and padding, greatly reduces the filling of the waterborne polyurethane slurry into the gaps between the ultrafine fibers, and the hot water fiber opening process is smooth and maintains the release structure between the ultrafine fibers and the waterborne polyurethane resin, thereby greatly improving the softness of the ultrafine leather.

[0026] In addition, during the impregnation process, the functional groups on the surface of the dopamine cross-linked membrane help promote the penetration and impregnation of the aqueous polyurethane slurry, fill the gaps in the island fibers, and help avoid the hollow core phenomenon at the position of the dopamine cross-linked membrane after fiber opening, thereby ensuring the specific compression rebound rate and crease recovery performance of the microfiber leather; the water-soluble powder in the aqueous polyurethane slurry will also dissolve with the water medium during fiber opening and form micropores, with good air permeability. DETAILED DESCRIPTION Example 1

[0027] The present embodiment provides an environmentally friendly sea island water-based microfiber suede leather, and its preparation process specifically includes the following steps: S1, pretreatment of non-woven fabric; S2, preparation of multi-layer base fabric; S3, impregnation with aqueous polyurethane slurry; S4, curing; S5, hot water fiber opening; S6, kneading and grinding to obtain sea island water-based microfiber suede leather.

[0028] In step S1, fixed-island type sea-island fiber non-woven fabrics are formed by opening, cotton opening, carding, web forming and pre-needling punching with fixed-island type sea-island fiber as raw material, wherein the sea component of the fixed-island type sea-island fiber is a water-soluble polymer and the island component is a water-insoluble polymer, specifically, the sea component is a water-soluble polyester WSPET, the island component is PET, the fineness is 5 dtex, and the number of islands is 37 islands.

[0029] The above-mentioned island-in-the-sea fiber nonwoven fabric is immersed in a dialdehyde-type oxidized sodium alginate aqueous solution at a temperature of 45°C and a dopamine buffer solution at a temperature of 45°C in sequence, the concentration of the dialdehyde-type oxidized sodium alginate aqueous solution is 1.5%-3.0% (specifically 1.5% in this embodiment), the concentration of the dopamine buffer solution is 2.5g / L-4.0g / L (specifically 3.0g / L in this embodiment), and the pH value is 8.5. The dialdehyde-type oxidized sodium alginate aqueous solution and the dopamine buffer solution are pressed at the output side of the dipping tank of the distilled sodium alginate aqueous solution and the output side of the distilled sodium alginate buffer solution, respectively, and the liquid pressing rate of the dialdehyde-type oxidized sodium alginate aqueous solution is 30%-40% (specifically 35% in this embodiment), and the liquid pressing rate of the dopamine buffer solution is 45%-55% (specifically 50% in this embodiment). Then, ultrasonic cross-linking is performed, with an ultrasonic power of 280-300 W (specifically 280 W in this embodiment) and an ultrasonic cross-linking time of 90 s-120 s (specifically 100 s in this embodiment), and then oven drying is performed to obtain a dopamine modified non-woven fabric, and a dopamine cross-linked film is formed on the surface of the fixed island type sea island fiber.

[0030] In step S2, a waterborne polyurethane mesh is used as an elastic middle layer and the dopamine-modified nonwoven fabric of step S1 is used as an upper and lower interlayer. The three layers are compounded and needle-punched to form a multi-layer base fabric. The needle-punching density is 800 punctures / cm 2 The weight of the multi-layer base fabric is 390g / m 2 .

[0031] In step S3, the multi-layer base fabric of step S2 is immersed in water-based polyurethane slurry, and then immersed twice and rolled twice, and the pressure of the two rollings is 30 kg / cm 2 and 10kg / cm 2 , the liquid carrying rate is 200%. The room temperature viscosity of the waterborne polyurethane slurry of this embodiment is 2500mPa•s, and the components are DIC WLI-630AR waterborne polyurethane, water-soluble acrylic oligomer with a polymerization rate of 95%, BYK1790 defoamer, leveling agent, DH-72165 thickener and deionized water, and the solid content is 30%. The water-soluble acrylic oligomer is obtained by copolymerizing acrylic acid, hydroxypropyl acrylate and N-hydroxymethyl acrylamide as monomers in an aqueous solution at a molar ratio of 5:4:1 under the action of an initiator.

[0032] In step S4, the microporous base semi-finished product is first dried at 90°C until the water volatilization rate reaches 85%, and then dried at 130°C to obtain a microporous base semi-finished product.

[0033] In step S5, deionized water is used as the medium for weight reduction treatment, and then drying is performed. The weight reduction treatment is specifically as follows: the microporous bass semi-finished product of step S4 is sequentially immersed in different fiber opening slots with increasing temperatures for hot water fiber opening: the first fiber opening slot has a water temperature of 75°C and a treatment time of 10 minutes; the second fiber opening slot has a water temperature of 85°C and a treatment time of 10 minutes; the third fiber opening slot has a water temperature of 90°C and a treatment time of 10 minutes; the fourth fiber opening slot has a water temperature of 95°C and a treatment time of 10 minutes; and each fiber opening slot outlet is subjected to two immersion and rolling treatments, with a pressure of 2.5 kg / cm 2 .

[0034] In step S6, the leather kneading speed is 4 m / min, and the temperature is set as follows: 95°C in the first zone, 120°C in the second zone, 125°C in the third zone, 130°C in the fourth zone, and 135°C in the fifth zone. The leather grinding speed is 4 m / min, the gap in the first zone is 0.6 mm, and the sanding belt is 300 mesh; the gap in the second zone is 0.4 mm, and the sanding belt is 500 mesh. Example 2

[0035] The present embodiment provides an environmentally friendly sea island water-based microfiber suede leather, and its preparation process specifically includes the following steps: S1, pretreatment of non-woven fabric; S2, preparation of multi-layer base fabric; S3, impregnation with aqueous polyurethane slurry; S4, curing; S5, hot water fiber opening; S6, kneading and grinding to obtain sea island water-based microfiber suede leather.

[0036] In step S1, the fixed-island type sea-island fiber is used as the raw material to form a fixed-island type sea-island fiber non-woven fabric through opening, cotton opening, carding, web forming and pre-needling, wherein the sea component of the fixed-island type sea-island fiber is a water-soluble polymer and the island component is a water-insoluble polymer, specifically, the sea component is a water-soluble polyester WSPET, the island component is PA6, the fineness is 5 dtex, and the number of islands is 37 islands.

[0037] The above-mentioned island-in-the-sea fiber nonwoven fabric is immersed in a dialdehyde-type oxidized sodium alginate aqueous solution at a temperature of 45°C and a dopamine buffer solution at a temperature of 45°C in sequence, the concentration of the dialdehyde-type oxidized sodium alginate aqueous solution is 1.5%-3.0% (specifically 2.0% in this embodiment), the concentration of the dopamine buffer solution is 2.5g / L-4.0g / L (specifically 3.0g / L in this embodiment), and the pH value is 8.5. The dialdehyde-type oxidized sodium alginate aqueous solution and the dopamine buffer solution are pressed at the output side of the dipping tank of the distilled sodium alginate aqueous solution and the output side of the distilled sodium alginate buffer solution, respectively, and the pressing rate of the dialdehyde-type oxidized sodium alginate aqueous solution is 30%-40% (specifically 30% in this embodiment), and the pressing rate of the dopamine buffer solution is 45%-55% (specifically 55% in this embodiment). Then, ultrasonic cross-linking is performed, with an ultrasonic power of 280-300 W (specifically 300 W in this embodiment) and an ultrasonic cross-linking time of 90 s-120 s (specifically 120 s in this embodiment), and then oven drying is performed to obtain a dopamine modified non-woven fabric, and a dopamine cross-linked film is formed on the surface of the fixed island type sea island fiber.

[0038] In step S2, a waterborne polyurethane mesh is used as an elastic middle layer and the dopamine-modified nonwoven fabric of step S1 is used as an upper and lower interlayer. The three layers are compounded and needle-punched to form a multi-layer base fabric. The needle-punching density is 650 thorns / cm 2 , the weight of the multi-layer base fabric is 420g / m 2 .

[0039] In step S3, the multi-layer base fabric of step S2 is immersed in water-based polyurethane slurry, and then immersed twice and rolled twice, and the pressure of the two rollings is 28 kg / cm 2 and 12kg / cm 2 The room temperature viscosity of the waterborne polyurethane slurry in this embodiment is 2200 mPa•s, and the components are DIC WLI-630AR waterborne polyurethane, water-soluble acrylic oligomer with a polymerization rate of 95%, BYK1790 defoamer, leveling agent, DH-72165 thickener and deionized water, and the solid content is 25%.

[0040] In step S4, the microporous base semi-finished product is first dried at 90°C until the water volatilization rate reaches 80%, and then dried at 135°C to obtain a microporous base semi-finished product.

[0041] In step S5, deionized water is used as the medium for weight reduction treatment, and then drying is performed. The weight reduction treatment is specifically as follows: the microporous bass semi-finished product of step S4 is sequentially immersed in different fiber opening slots with increasing temperatures for hot water fiber opening: the first fiber opening slot has a water temperature of 80°C and a treatment time of 8 minutes; the second fiber opening slot has a water temperature of 85°C and a treatment time of 8 minutes; the third fiber opening slot has a water temperature of 90°C and a treatment time of 10 minutes; the fourth fiber opening slot has a water temperature of 95°C and a treatment time of 10 minutes; and each fiber opening slot outlet is subjected to two immersion and rolling treatments, with a pressure of 3kg / cm 2 .

[0042] In step S6, the leather kneading speed is 4 m / min, and the temperature is set as follows: 98°C in the first zone, 125°C in the second zone, 125°C in the third zone, 130°C in the fourth zone, and 135°C in the fifth zone. The leather grinding speed is 4 m / min, the gap in the first zone is 1.0 mm, and the sanding belt is 350 mesh; the gap in the second zone is 0.6 mm, and the sanding belt is 500 mesh.

[0043] Comparative Example 1

[0044] The only difference between this comparative example and the above-mentioned Example 1 is that no dialdehyde-type oxidized sodium alginate is impregnated in step S1.

[0045] Comparative Example 2

[0046] The difference between this comparative example and the above-mentioned embodiment 1 is that the two-pass padding pressure in step S5 is changed to 8 kg / cm 2 .

[0047] The softness of the impregnated microfiber leather was measured using the GT-303 leather softness tester: the microfiber leather was cut into the required rectangular fabric sample, and then placed on the instrument base, the pressing handle was first folded down to make the probe completely retracted, and the base fabric was clamped between the clamping seats, the upper arm was locked, and the pointer rotated after the hand was released. After the pointer stabilized, the pointer reading was read. Among them: the softness of Examples 1 and 2 was 7.76 and 7.62 respectively, while the softness of Comparative Examples 1 and 2 was 6.97 and 7.33 respectively.

[0048] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention shall be defined by the attached claims and their equivalents.

Claims

1. A process for preparing environmentally friendly sea island water-based microfiber suede leather, characterized in that: The specific steps include: S1. Pretreatment of nonwoven fabric: taking a fixed-island fiber nonwoven fabric, immersing it in a dialdehyde-type oxidized sodium alginate aqueous solution and a dopamine buffer solution in turn, then performing ultrasonic cross-linking, and then drying it in an oven to obtain a dopamine-modified nonwoven fabric, and forming a dopamine cross-linked film on the surface of the fixed-island fiber; The sea component of the island-in-the-sea microfiber is a water-soluble polymer and the island component is a water-insoluble polymer; S2, preparing a multi-layer base fabric: taking a water-based polyurethane mesh as an elastic middle layer and the dopamine-modified non-woven fabric of step S1 as an upper and lower interlayer, and compounding the three layers and needle-punching to form a multi-layer base fabric; S3, impregnating with water-based polyurethane slurry: impregnating the multi-layer base fabric of step S2 with water-based polyurethane slurry, double dipping and double rolling, the room temperature viscosity is 2000mPa·s~2500mPa·s, and the liquid carrying rate is 150%-200%; the components of the polyurethane slurry are water-based polyurethane, water-soluble powder, defoamer, leveling agent, thickener and deionized water, and the solid content is 25%-30%; S4, curing: firstly drying at a medium temperature of 85°C to 90°C until the water volatilization rate reaches 80%-85%, and then drying at a high temperature of 120°C to 135°C to obtain a microporous base semi-finished product; S5. Hot water fiber opening: Use deionized water at a temperature of 75℃-95℃ as the medium for weight reduction treatment for 30min-50min, and then dry; S6. Soften and grind the leather to obtain sea island water-based microfiber suede.

2. The process for preparing the environmentally friendly sea island water-based microfiber suede leather according to claim 1, characterized in that: The fineness of the island-in-the-sea fibers in step S1 is 1.5 dtex to 6.5 dtex, and the number of islands is 37.

3. The process for preparing the environmentally friendly sea island water-based microfiber suede leather according to claim 1, characterized in that: The sea component of the island-in-the-sea fibers in step S1 is water-soluble polyester WSPET, and the island components are PET or PA6.

4. The process for preparing the environmentally friendly sea island water-based microfiber suede leather according to claim 1, characterized in that: The acupuncture density in step S2 is 600 to 800 punctures / cm 2 , the weight of the multi-layer base fabric is 250g / m 2 ~450g / m 2 .

5. The process for preparing the environmentally friendly sea island water-based microfiber suede leather according to claim 1, characterized in that: The water-soluble powder is a water-soluble acrylic acid oligomer with a polymerization rate of 95%.

6. The process for preparing the environmentally friendly sea island water-based microfiber suede leather according to claim 1, characterized in that: The second rolling pressure in step S3 is 25kg / cm 2 ~30kg / cm 2 and 10kg / cm 2 ~12kg / cm 2 .

7. The process for preparing the environmentally friendly sea island water-based microfiber suede leather according to claim 1, characterized in that: The weight reduction treatment in step S5 is specifically as follows: the microporous bass semi-finished product of step S4 is sequentially immersed in different fiber opening grooves with increasing temperatures for hot water fiber opening, the water temperature increment is 5°C-10°C, the treatment time of each fiber opening groove is 10min±3min, and two immersion padding treatments are performed at the outlet of each fiber opening groove, and the pressure is 2kg / cm 2 ~4kg / cm 2 .

8. The process for preparing the environmentally friendly sea island water-based microfiber suede leather according to claim 1, characterized in that: The leather kneading and softening speed in step S6 is 4m / min-5m / min, and the temperature is set as follows: 95°C-100°C in the first zone, 120°C-125°C in the second zone, 120°C-125°C in the third zone, 125°C-135°C in the fourth zone, and 130°C-135°C in the fifth zone.

9. The process for preparing the environmentally friendly sea island water-based microfiber suede leather according to claim 1, characterized in that: The leather grinding speed in step S6 is 4m / min-5m / min, the gap in the first zone is 0.6mm-1.2mm, and the sanding belt has 250-350 meshes; the gap in the second zone is 0.4mm-0.8mm, and the sanding belt has 350-500 meshes.

10. Environmentally friendly sea island water-based microfiber suede leather prepared by the preparation process according to any one of claims 1 to 9.