A color fixing process for microfiber suede leather

Abstract

The present invention belongs to the technical field of microfiber suede finishing, and relates to a microfiber suede color fixing process, comprising the steps of: (a) after finishing the shape memory material on the bottom of the pile of the microfiber suede, shaping the shape memory material; before finishing and shaping, the surface pile of the microfiber suede is in an upright state; (b) performing a color fixing treatment on the microfiber suede, the color fixing treatment is divided into three stages, the first stage is the stage of impregnating and rolling the color fixing finishing liquid, the second stage is the stage of wet heat treatment, and the third stage is the stage of baking, and the conditions of the wet heat treatment are controlled so that the shape memory material is restored to the original shape in the second stage, and the color fixing agent is prevented from forming a film in the second stage. The present invention effectively solves the problems that the existing color fixing process is easy to flatten the pile, destroy the pile feeling, and the color fixing effect is easy to weaken, and can significantly improve the wet friction color fastness of the microfiber suede, while well maintaining its excellent pile feeling.

Description

Technical Field

[0001] The invention belongs to the technical field of microfiber suede leather post-finishing, and relates to a microfiber suede leather color fixing process. Background Art

[0002] Micro suede leather has been widely used in many fields such as clothing and home decoration due to its unique texture and excellent performance. However, it is still a big challenge to produce micro suede leather with high rubbing color fastness and excellent suede feeling, especially in dark colors. The wet rubbing color fastness of such products often fails to meet the expected standards of consumers.

[0003] At present, the mainstream color fixing process for improving wet friction color fastness mostly adopts the method of attaching water-based polyurethane to the surface of suede to form a film, such as the method for synthesizing a water-based polyurethane color fixing agent disclosed in patent application CN109667175A. However, in this type of color fixing process, the color fixing agent is pressed into the suede by the action of the pressure roller, causing the suede fibers to fall over. Since the color fixing agent will adhere to the fibers of the suede and form a film layer, it is easy to flatten the surface of the suede and make it difficult to recover. After color fixing, the skin is polished and it is easy to destroy the color fixing agent film that has been formed, thereby weakening the color fixing effect.

[0004] Therefore, there is an urgent need for a new color fixing process that can effectively improve the wet friction color fastness of microfiber suede leather while maintaining its excellent velvety feel. Summary of the invention

[0005] The purpose of the invention is to solve the problems existing in the prior art and provide a microfiber suede leather color fixing process.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A microfiber suede leather color fixing process comprises the following steps:

[0008] (a) After the shape memory material is arranged on the nap bottom of the microfiber suede leather, the shape memory material is subjected to shaping treatment;

[0009] Before finishing and shaping, the surface pile of microfiber suede is in an upright state;

[0010] Before finishing, controlling the surface fuzz of the microfiber suede to be in an upright state is conducive to realizing that the shape memory material is mainly arranged on the bottom of the fuzz of the microfiber suede; before shaping treatment, controlling the surface fuzz of the microfiber suede to be in an upright state is to ensure that when the subsequent shape memory material is restored to its original shape, the surface fuzz of the microfiber suede is in an upright state;

[0011] The shape memory material is a mixture of EPU and TPU in a mass ratio of 1:9-4:6. This is a known technology. The reason why the mixture of EPU and TPU has shape memory properties is that there are a large number of MDI-EG hard segments in EPU, which have strong polarity and form physical crosslinking points through hydrogen bonding, which mainly contribute to the fixed phase of the shape memory material. There are a large number of PBA soft segments in TPU, which have a relatively regular structure and certain crystallinity, which mainly contribute to the reversible phase of the shape memory material.

[0012] The shaping treatment temperature is 60-80°C and the shaping treatment time is at least 4 minutes, so that the shape memory material can undergo a sufficient phase change;

[0013] (b) The microfiber suede is subjected to a color fixing treatment, which is divided into three stages: the first stage is a stage of dipping and rolling in a color fixing finishing liquid, the second stage is a stage of wet heat treatment, and the third stage is a stage of baking (during which water evaporates and the color fixing agent forms a film). The conditions of the wet heat treatment are controlled so that the shape memory material can be restored to its original shape in the second stage, while preventing the color fixing agent from forming a film in the second stage.

[0014] As the preferred technical solution:

[0015] In the above-mentioned microfiber suede color fixing process, in step (b), the wet heat treatment temperature is 60-80°C, and the wet heat treatment time is 4-6 minutes. The wet heat treatment time should not be too long, otherwise excessive evaporation of water will cause the color fixing agent to form a film prematurely. The wet heat treatment time should not be too short, otherwise the shape memory material will be difficult to restore to its original shape.

[0016] In the above-mentioned microfiber suede leather fixing process, in step (b), the relative humidity of the wet heat treatment is at least 50%. The relative humidity of the wet heat treatment should not be too low, otherwise it is difficult to effectively inhibit water evaporation, resulting in premature film formation after the fixing agent loses water.

[0017] In the above-mentioned microfiber suede leather fixing process, in step (b), when the fixing finishing liquid is rolled, the concentration of the fixing agent in the fixing finishing liquid is 1-3wt%, the roller pressure is 0.1-0.3MPa, and the liquid carrying rate of the microfiber suede leather after the rolling is 40-60%.

[0018] In the above-mentioned microfiber suede leather color fixing process, in step (b), the baking temperature is 120-140° C. and the baking time is 3-5 minutes.

[0019] In the above-mentioned microfiber suede leather color fixing process, step (a) is specifically as follows:

[0020] (a1) Printing;

[0021] When the suede on the surface of the microfiber suede is in an upright state, a shape memory material solution is used to print the suede surface of the microfiber suede;

[0022] The printing amount of shape memory material on microfiber suede is 30-60g / m 2 The printing amount within this range can prevent the excessive coating of the fiber due to excessive printing amount, which will destroy the velvet feeling, and can also avoid the fact that the shape memory material on the fiber surface is too little due to too small printing amount, which cannot effectively prevent the velvet feeling of the microfiber suede from being destroyed after color fixing;

[0023] (a2) drying after standing;

[0024] After the printed microfiber suede is left to stand for more than 10 seconds, the solvent in the shape memory material solution is dried; the standing time is designed in this way to facilitate the shape memory material to fully enter the bottom of the pile of the microfiber suede, reduce the damage to the shape memory material in the subsequent leather grinding and napping process, and make it impossible for the shape memory material to promote the recovery of the pile to an upright state;

[0025] (a3) microdermabrasion;

[0026] The purpose of leather grinding and napping is to restore the velvet feeling damaged by printing, so that the surface velvet of the microfiber suede is in an upright state before shaping treatment; technicians in this field can flexibly adjust the rotation speed of leather grinding and the mesh number of the napping sandpaper according to the desired velvet feeling. Specifically, the mesh number of the napping sandpaper can be 80 mesh, 120 mesh, 150 mesh or 180 mesh. At the same time, the rotation speed of leather grinding is usually controlled between 200-300r / min to avoid excessive grinding of the velvet due to excessive rotation speed, or the machine cannot operate normally due to too low rotation speed;

[0027] (a4) Shaping treatment.

[0028] In the above-mentioned microfiber suede color fixing process, in step (a1), the solvent in the shape memory material solution is a good solvent for EPU / TPU, such as DMF, and the mass of the solvent in the shape memory material solution is 1-1.5 times the mass of the solute;

[0029] Exemplarily, in step (a2), the drying temperature is 140-160° C., the drying time is 3-10 min, and the purpose of drying is to completely remove the solvent.

[0030] Beneficial effects:

[0031] The microfiber suede leather color fixing process of the present invention effectively solves the problems that the existing color fixing process is easy to flatten the fuzz, destroy the fuzz feeling and the color fixing effect is easy to weaken. It can significantly improve the wet friction color fastness of the microfiber suede leather, while well maintaining its excellent fuzz feeling, and meets the production demand for microfiber suede leather with both high friction color fastness and good fuzz feeling.

[0032] The wet friction color fastness of the microfiber suede leather after color fixing treatment is level 4, and the fuzz is in an upright state. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The nap state of the microfiber suede leather after the color fixing treatment of Example 1 observed with a high-power identification magnifying glass;

[0034] Figure 2 The nap state of the microfiber suede leather of Comparative Example 1 after the color fixing treatment was observed with a magnifying glass using high-power identification. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0036] The following are the test methods for the relevant performance indicators in each embodiment and comparative example:

[0037] Wet rubbing color fastness: Determine the color fastness to wet rubbing according to the test method for color fastness to wet rubbing disclosed in ISO 105-X12:2016 “Textiles - Tests for color fastness - Part X12: Color fastness to rubbing”.

[0038] Villus state: Use a high-power identification magnifying glass to observe the villus lodging / erect state from the cut surface.

[0039] The following is the source information of the materials used in each example:

[0040] EPU: The manufacturer is Suzhou Jinjieyou High-tech Materials Co., Ltd., brand number 790;

[0041] TPU: The manufacturer is Taiwan Province, China, Ji Er Nai Industrial Co., Ltd., the brand is TPUI-L70;

[0042] Microfiber suede leather: dyed EDEH8 (manufacturer: Shanghai Huafeng Microfiber Technology Co., Ltd.); the dyeing liquid formula is: red (DyStar, AM-SLR) 0.3% owf, navy blue (DyStar, AM-G) 1.2% owf, black (DyStar, AM-R) 2.7% owf, leveling agent 1 (DyStar, M-IS) 0.5% owf, leveling agent 2 (DyStar, P-BMO) 0.5% owf, the dyeing medium is water; the bath ratio is 1:20, and the dyeing process is: first heat up to 70°C at a heating rate of 2°C / min at room temperature, then heat up to 130°C at a heating rate of 1.5°C / min, and then dye at 130°C for 60 minutes, and then cool to room temperature at a cooling rate of 5°C / min. After drying, the microfiber suede leather has its original free upright state, and the wet friction color fastness is level 2;

[0043] Fixing agent: The manufacturer is Guangdong Demei Fine Chemical Co., Ltd., and the brand number is DM-2589.

[0044] Example 1

[0045] A microfiber suede leather color fixing process, the specific steps are as follows:

[0046] (1) Preparation of materials;

[0047] Micro suede;

[0048] Shape memory material solution: the shape memory material (ie, solute) is a mixture of EPU and TPU in a mass ratio of 1:9, the solvent is DMF, and the mass of the solvent is 1 times the mass of the solute;

[0049] Color fixing finishing liquid: the solute is the color fixing agent, the solvent is water, and the concentration is 1wt%;

[0050] (2)Printing;

[0051] When the hairs on the surface of the microfiber suede are in an upright state, the surface of the microfiber suede is printed with a shape memory material solution; wherein the printing amount of the shape memory material on the microfiber suede is 30g / m 2 ;

[0052] (3) Drying after standing;

[0053] The printed microfiber suede was left to stand for 10 seconds and then dried at 140°C for 6 minutes to remove the solvent.

[0054] (4) grinding and raising the microfiber suede leather after drying;

[0055] (5) Shaping treatment;

[0056] The microfiber suede leather after grinding and napping was shaped at 80℃ for 4 minutes;

[0057] After shaping, the wet rubbing color fastness of the microfiber suede is level 2, and the nap is in an upright state;

[0058] (6) Color fixation treatment;

[0059] First, the roller pressure is set to 0.1MPa, and the microfiber suede leather after shaping treatment is immersed in the color fixing finishing liquid to obtain a microfiber suede leather with a liquid rate of 60%, and then the microfiber suede leather is subjected to wet heat treatment at a temperature of 60°C and a relative humidity of 50% for 4 minutes, and then the microfiber suede leather is baked at 120°C for 5 minutes to complete the color fixing of the microfiber suede leather.

[0060] The test shows that the wet friction color fastness of the microfiber suede leather after color fixation treatment is level 4, and the fuzz is in an upright state (such as Figure 1 shown).

[0061] Comparative Example 1

[0062] A microfiber suede color fixing process, which is different from Example 1 only in that the shape memory material is replaced by EPU of equal mass.

[0063] After the color fixation treatment, the nap of the microfiber suede is in a state of lodging (such as Figure 2 This is because when the shape memory material is replaced with EPU of equal mass, the pure EPU does not have the shape memory function. Under the same color fixing process conditions, after immersion in the color fixing finishing liquid, the villi fall down and the EPU deforms. In the subsequent wet heat treatment at a temperature of 60°C and a relative humidity of 50% for 4 minutes, the shape of the EPU cannot be effectively restored and cannot drive the villi to restore uprightness before the color fixing agent forms a film.

[0064] Comparative Example 2

[0065] A microfiber suede color fixing process, which is different from Example 1 only in that the shape memory material is replaced by TPU of equal quality.

[0066] The hair of the microfiber suede leather after the color fixing treatment is in a collapsed state. This is because when the shape memory material is replaced by TPU of equal mass, although the pure TPU has the power to recover through phase change, it still does not have the shape memory function due to the lack of rigid materials that constitute the shape skeleton of the material. Under the same color fixing process conditions, after immersion in the color fixing finishing liquid, the hair falls over and the TPU is deformed; in the subsequent wet heat treatment at a temperature of 60°C and a relative humidity of 50% for 4 minutes, the morphology of the TPU cannot be effectively restored and cannot drive the hair to resume uprightness before the color fixing agent forms a film.

[0067] Comparative Example 3

[0068] A microfiber suede leather color fixing process, which is different from Example 1 only in that the temperature of the shaping treatment is 50°C.

[0069] The hair of the microfiber suede leather is in a collapsed state after the color fixing treatment. This is because the shaping treatment is carried out at an overly low temperature, and the shape memory material cannot produce sufficient phase change and cannot effectively fix the original upright shape of the hair of the microfiber suede leather. During subsequent color fixing treatments and other operations, the collapsed hair cannot be restored to an upright state, which ultimately causes the hair to be in a collapsed state.

[0070] Comparative Example 4

[0071] A microfiber suede leather color fixing process, which is different from Example 1 only in that the shaping treatment time is 2 minutes.

[0072] The hair of the microfiber suede leather is in a collapsed state after the color fixing treatment. This is because the insufficient shaping time makes it impossible for the shape memory material to produce sufficient phase change and effectively fix the original upright shape of the hair of the microfiber suede leather. In the subsequent color fixing treatment and other operations, after the color fixing agent forms a film and solidifies, the collapsed hair cannot be restored to an upright state, which eventually causes the hair to be in a collapsed state.

[0073] Comparative Example 5

[0074] A microfiber suede color fixing process, which is different from Example 1 only in that the temperature of the wet heat treatment is 50°C.

[0075] The pile of the microfiber suede leather after the color fixing treatment is in a fallen state. This is because the temperature of the wet heat treatment is too low, and the shape memory material cannot fully recover to its original shape and cannot effectively exert its shape memory function to restore the pile to an upright state.

[0076] Comparative Example 6

[0077] A microfiber suede color fixing process, which is different from Example 1 only in that the temperature of the wet heat treatment is 100°C.

[0078] The hair of the microfiber suede leather after the color fixing treatment is in a fallen state. This is because the temperature of the wet heat treatment is too high, which significantly accelerates the water loss rate of the color fixing finishing liquid, resulting in the color fixing agent forming a film prematurely before the fiber has time to return to the upright state. The prematurely formed color fixing agent film prevents the hair from returning to the upright state in the subsequent process.

[0079] Comparative Example 7

[0080] A microfiber suede color fixing process, which is different from Example 1 only in that the wet heat treatment time is 3 minutes.

[0081] The hair of the microfiber suede leather after the color fixing treatment is in a collapsed state. This is because the wet heat treatment time is too short, and the shape memory material does not have enough time to recover to its original shape, causing its shape memory function to not be effectively exerted, and the collapsed hair cannot be restored to an upright state, which ultimately causes the hair to be in a collapsed state.

[0082] Example 2

[0083] A microfiber suede leather color fixing process, the specific steps are as follows:

[0084] (1) Preparation of materials;

[0085] Micro suede;

[0086] Shape memory material solution: the shape memory material (ie, solute) is a mixture of EPU and TPU in a mass ratio of 2:8, the solvent is DMF, and the mass of the solvent is 1.2 times the mass of the solute;

[0087] Color fixing finishing liquid: the solute is the color fixing agent, the solvent is water, and the concentration is 2wt%;

[0088] (2)Printing;

[0089] When the hairs on the surface of the microfiber suede are in an upright state, the surface of the microfiber suede is printed with a shape memory material solution; wherein the printing amount of the shape memory material on the microfiber suede is 40g / m 2 ;

[0090] (3) Drying after standing;

[0091] The printed microfiber suede was left to stand for 15 seconds and then dried at 150°C for 5 minutes to remove the solvent.

[0092] (4) grinding and raising the microfiber suede leather after drying;

[0093] (5) Shaping treatment;

[0094] The microfiber suede leather after grinding and napping was shaped at 70℃ for 5 minutes;

[0095] After shaping, the wet rubbing color fastness of the microfiber suede is level 2, and the nap is in an upright state;

[0096] (6) Color fixation treatment;

[0097] First, set the roller pressure to 0.2MPa, immerse the shaping microfiber suede leather in the color fixing finishing liquid to obtain a microfiber suede leather with a liquid rate of 50%, then wet heat treat the microfiber suede leather at a temperature of 70°C and a relative humidity of 55% for 5 minutes, and then bake the microfiber suede leather at 120°C for 3 minutes to complete the color fixing of the microfiber suede leather.

[0098] Tests show that the wet friction color fastness of the microfiber suede leather after color fixing treatment is level 4, and the fuzz is in an upright state.

[0099] Example 3

[0100] A microfiber suede leather color fixing process, the specific steps are as follows:

[0101] (1) Preparation of materials;

[0102] Micro suede;

[0103] Shape memory material solution: the shape memory material (ie, solute) is a mixture of EPU and TPU in a mass ratio of 3:7, the solvent is DMF, and the mass of the solvent is 1 times the mass of the solute;

[0104] Color fixing finishing liquid: the solute is the color fixing agent, the solvent is water, and the concentration is 3wt%;

[0105] (2)Printing;

[0106] When the hairs on the surface of the microfiber suede are in an upright state, the surface of the microfiber suede is printed with a shape memory material solution; wherein the printing amount of the shape memory material on the microfiber suede is 50g / m 2 ;

[0107] (3) Drying after standing;

[0108] The printed microfiber suede was left to stand for 20 seconds and then dried at 160°C for 3 minutes to remove the solvent.

[0109] (4) grinding and raising the microfiber suede leather after drying;

[0110] (5) Shaping treatment;

[0111] The microfiber suede leather after grinding and napping was shaped at 75℃ for 6 minutes;

[0112] After shaping, the wet rubbing color fastness of the microfiber suede is level 2, and the nap is in an upright state;

[0113] (6) Color fixation treatment;

[0114] First, the roller pressure is set to 0.3MPa, and the microfiber suede leather after shaping treatment is immersed in the color fixing finishing liquid to obtain a microfiber suede leather with a liquid rate of 40%, and then the microfiber suede leather is subjected to wet heat treatment at a temperature of 60°C and a relative humidity of 50% for 5 minutes, and then the microfiber suede leather is baked at 140°C for 5 minutes to complete the color fixing of the microfiber suede leather.

[0115] Tests show that the wet friction color fastness of the microfiber suede leather after color fixing treatment is level 4, and the fuzz is in an upright state.

[0116] Example 4

[0117] A microfiber suede leather color fixing process, the specific steps are as follows:

[0118] (1) Preparation of materials;

[0119] Micro suede;

[0120] Shape memory material solution: the shape memory material (ie, solute) is a mixture of EPU and TPU in a mass ratio of 4:6, the solvent is DMF, and the mass of the solvent is 1.5 times the mass of the solute;

[0121] Color fixing finishing liquid: the solute is the color fixing agent, the solvent is water, and the concentration is 3wt%;

[0122] (2)Printing;

[0123] When the hairs on the surface of the microfiber suede are in an upright state, the surface of the microfiber suede is printed with a shape memory material solution; wherein the printing amount of the shape memory material on the microfiber suede is 60g / m 2 ;

[0124] (3) Drying after standing;

[0125] The printed microfiber suede was left to stand for 18 seconds and then dried at 160°C for 10 minutes to remove the solvent.

[0126] (4) grinding and raising the microfiber suede leather after drying;

[0127] (5) Shaping treatment;

[0128] The microfiber suede leather after grinding and napping was shaped at 60℃ for 4 minutes;

[0129] After shaping, the wet rubbing color fastness of the microfiber suede is level 2, and the nap is in an upright state;

[0130] (6) Color fixation treatment;

[0131] First, the roller pressure is set to 0.3MPa, and the microfiber suede leather after shaping treatment is immersed in the color fixing finishing liquid to obtain a microfiber suede leather with a liquid rate of 40%, and then the microfiber suede leather is subjected to wet heat treatment at a temperature of 80°C and a relative humidity of 60% for 6 minutes, and then the microfiber suede leather is baked at 130°C for 4 minutes to complete the color fixing of the microfiber suede leather.

[0132] Tests show that the wet friction color fastness of the microfiber suede leather after color fixing treatment is level 4, and the fuzz is in an upright state.

Claims

1. A color fixing process for microfiber suede leather, characterized in that: The following steps are involved: (a) After the shape memory material is arranged on the nap bottom of the microfiber suede leather, the shape memory material is subjected to shaping treatment; Before finishing and shaping, the surface pile of microfiber suede is in an upright state; The shape memory material is a mixture of EPU and TPU in a mass ratio of 1:9-4:6; The shaping treatment temperature is 60-80°C and the shaping treatment time is at least 4 minutes; (b) The microfiber suede leather is subjected to a color fixing treatment, and the color fixing treatment is divided into three stages. The first stage is a stage of dipping and padding a color fixing finishing liquid, the second stage is a stage of wet heat treatment, and the third stage is a stage of baking. The conditions of the wet heat treatment are controlled so that the shape memory material can be restored to its original shape in the second stage, and at the same time, the color fixing agent is prevented from forming a film in the second stage.

2. The microfiber suede leather color fixing process according to claim 1, characterized in that: In step (b), the wet heat treatment temperature is 60-80° C., and the wet heat treatment time is 4-6 min.

3. The microfiber suede leather color fixing process according to claim 2, characterized in that: In step (b), the relative humidity during the moist heat treatment is at least 50%.

4. The microfiber suede leather color fixing process according to claim 1, characterized in that: In step (b), when the color fixing finishing liquid is padded, the concentration of the color fixing agent in the color fixing finishing liquid is 1-3wt%, the roller pressure is 0.1-0.3MPa, and the liquid carrying rate of the microfiber suede leather after the padded is 40-60%.

5. The microfiber suede leather color fixing process according to claim 1, characterized in that: In step (b), the baking temperature is 120-140° C. and the baking time is 3-5 min.

6. The microfiber suede leather color fixing process according to claim 1, characterized in that: Step (a) is as follows: (a1) Printing; When the suede on the surface of the microfiber suede is in an upright state, a shape memory material solution is used to print the suede surface of the microfiber suede; The printing amount of shape memory material on microfiber suede is 30-60g / m 2 ; (a2) drying after standing; After the printed microfiber suede is left to stand for more than 10 seconds, the solvent in the shape memory material solution is dried; (a3) microdermabrasion; (a4) Shaping treatment.

7. The microfiber suede leather color fixing process according to claim 6, characterized in that: In step (a1), the mass of the solvent in the shape memory material solution is 1-1.5 times the mass of the solute.

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