A low-odor ultra-fine fiber synthetic leather, its preparation method, and the deodorant used

Abstract

The present invention relates to a low-odor ultra-fine fiber synthetic leather, a preparation method thereof, and a deodorant used. The polyurethane ultra-fine fiber synthetic leather is immersed in a mixed solution, and by means of padding, the liquor pickup is controlled to be 30-60%, and then dried to cure the mixed solution, forming a cured film inside the polyurethane ultra-fine fiber synthetic leather, thereby obtaining the low-odor ultra-fine fiber synthetic leather; a cured film covers the surface of the ultra-fine fibers inside the low-odor ultra-fine fiber synthetic leather; the crosslinking degree of the cured film is above 70%; the mixed solution includes deionized water, bifunctional amino acids, trifunctional amino acids, and carbodiimide, that is, the deodorant; a cured film exists on the surface of the low-odor ultra-fine fiber synthetic leather of the present invention, which can react with the gas emitted by the ultra-fine fiber synthetic leather, thereby making it have a low odor; the deodorant used in the present invention can eliminate the influence of ammonia and aldehydes on the odor of the ultra-fine fiber leather; the preparation method of the present invention is simple to prepare.

Description

Technical Field

[0001] The present invention belongs to the technical field of deodorants, and relates to a low-odor ultra-fine fiber synthetic leather, a preparation method thereof, and a deodorant used therefor. Background Art

[0002] Polyurethane ultra-fine fiber synthetic leather (hereinafter referred to as ultra-fine leather) has excellent texture and soft hand feeling, and is widely used in the interior decoration field of automobiles and the field of indoor household products. With the improvement of living standards, the requirements for the smell in the room or cockpit are getting higher and higher. Ultra-fine leather is mainly composed of two parts: polyurethane and ultra-fine fibers. Among them, the fineness of the ultra-fine fibers is below 0.55 dtex, the fiber diameter is very fine, the specific surface area is large, and it has good adsorption. Small molecular substances with odor will be adsorbed on the fiber surface. Therefore, at room temperature (within 30 °C), the odor property of ultra-fine leather is better than that of conventional leathers, such as genuine leather, PVC leather, PU leather prepared from non-ultra-fine substrates, and so on.

[0003] However, at high temperatures (above 65 °C), small molecular substances adsorbed on the ultra-fine fibers, mainly ammonia, aldehydes and benzene substances, will desorb from the fibers, thus affecting the odor property of ultra-fine leather. Tests have shown that when a car is exposed to the sun outdoors at a high temperature of 40 °C for a long time, the temperature inside the car is above 70 °C, and the highest can reach 90 °C. Therefore, a large number of small molecular substances adsorbed on the ultra-fine leather fibers will be emitted, forming an unpleasant smell.

[0004] In the currently disclosed patents, most of the deodorization methods of deodorants are carried out by absorption methods using substances with a large specific surface area, such as diatomite, activated carbon, porous materials, etc. For example, Patent CN113876989A uses diatomite, and Patent CN113713786A uses porous silica. This treatment, like the adsorption effect of ultra-fine fibers, is only effective at room temperature. There are also some patents that use some materials to absorb small molecules, but these materials themselves have odor or will release odor. For example, 2-aminoisobutanol used in Patent CN108043207A itself has odor, and most alkanolamine compounds are irritating to the human body; ethylenediamine used in Patent CN113755655A itself is a substance with an ammonia odor and has medium toxicity to the human body.

[0005] Therefore, it is of great significance to study a low-odor ultra-fine fiber synthetic leather, a preparation method thereof, and a deodorant used therefor. Summary of the Invention

[0006] To solve the problems existing in the prior art, the present invention provides a low-odor ultra-fine fiber synthetic leather, a preparation method thereof, and a deodorant used therefor;

[0007] To achieve the above object, the following scheme is adopted in the present invention:

[0008] A low-odor ultrafine fiber synthetic leather, wherein the surface of the ultrafine fibers inside the low-odor ultrafine fiber synthetic leather is covered with a cured film;

[0009] The cured film comprises a bifunctional amino acid residue, a trifunctional amino acid residue and a carbodiimide residue. The bifunctional amino acid residue and the trifunctional amino acid residue are connected by an amide bond, and the carbodiimide residue is connected to the bifunctional amino acid residue and the trifunctional amino acid residue by an amide bond; the amount of substance of the trifunctional amino acid residue is 0.34 to 2 times that of the bifunctional amino acid residue; the amount of substance of the carbodiimide residue is 0.1 to 1 times that of the bifunctional amino acid residue;

[0010] To ensure that the cured film has a sufficient network structure, the crosslinking degree of the cured film is above 70% (70-100%);

[0011] The material of the ultrafine fibers in the ultrafine fiber synthetic leather is polyamide.

[0012] As a preferred technical solution:

[0013] For the low-odor ultrafine fiber synthetic leather as described above, the terminal amino group concentration in the cured film is not less than 200 ppm / kg, and the terminal carboxyl group concentration is not less than 80 ppm / kg; the terminal amino group concentration and the terminal carboxyl group concentration in the cured film are both not higher than 1000 ppm / kg.

[0014] The carboxyl group can chemically react with the amino group of ammonia to form an amide or an ammonium salt; the amino group can chemically react with aldehydes to form a hydroxymethyl derivative; that is, odorless substances are formed through the reaction, thereby eliminating the odor problem caused by the release of ammonia and aldehydes at high temperatures from the ultrafine fibers. Experiments have found that the cured film with high terminal amino group and terminal carboxyl group contents has a more significant odor removal effect than the amino acid cured film with low terminal amino group and terminal carboxyl group contents. According to the cumulative aldehyde release test data of ultrafine fiber leathers of different specifications in the past, the cumulative release amount of the ultrafine fiber leather reaches the release equilibrium when it is 136 ppm / kg or even smaller. The terminal amino group concentration in the cured film should be controlled to be at least 200 ppm / kg, far exceeding the amount that the ultrafine fiber leather can release; according to the ammonia release test of ultrafine fiber leathers of different specifications, the cumulative release amount of the ultrafine fiber leather reaches the release equilibrium when it is 53 ppm / kg or even smaller. The terminal carboxyl group concentration in the cured film should be controlled to be at least 80 ppm / kg, far exceeding the amount that the ultrafine fiber leather can release; therefore, the terminal amino group concentration in the cured film is not less than 200 ppm / kg, and the terminal carboxyl group concentration is not less than 80 ppm / kg; and the terminal amino group concentration and the terminal carboxyl group concentration in the cured film are both not higher than 1000 ppm / kg, because too high terminal amino group concentration and terminal carboxyl group concentration, manifested as a low polymer in the system, will make the effect of the cured film blocking gas overflow worse.

[0015] A low-odor ultrafine fiber synthetic leather as described above, wherein the mass ratio of the curing film in the low-odor ultrafine fiber synthetic leather is 0.04-10.34%.

[0016] The present invention also provides an odor remover used in the manufacturing process of a low-odor ultrafine fiber synthetic leather as described in any one of the above, the odor remover includes deionized water, bifunctional amino acids, trifunctional amino acids and carbodiimide;

[0017] The mass ratio of deionized water to bifunctional amino acids is 1000:1-30;

[0018] The amount of substance of trifunctional amino acids is 0.34-2 times that of bifunctional amino acids;

[0019] The amount of substance of carbodiimide is 0.1-1 times that of bifunctional amino acids.

[0020] As a preferred technical solution:

[0021] For the odor remover as described above, the bifunctional amino acid is one or more of glycine, valine, leucine, phenylalanine, serine, asparagine, glutamine, threonine and histidine, these are odorless amino acids, and the decomposition temperature ≥ 185 °C to ensure that decomposition does not occur at the curing temperature.

[0022] For the odor remover as described above, the trifunctional amino acid is one or more of aspartic acid, lysine and arginine, these are odorless amino acids, and the decomposition temperature ≥ 185 °C to ensure that decomposition does not occur at the curing temperature.

[0023] For the odor remover as described above, the carbodiimide is one or more of N,N'-diisopropylcarbodiimide (DIC), dicyclohexylcarbodiimide (DCC) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC, CAS No.: 25952-53-8).

[0024] The present invention also provides a preparation method of a low-odor ultrafine fiber synthetic leather as described in any one of the above, dipping the polyurethane ultrafine fiber synthetic leather into the mixed solution, and by means of padding, controlling the liquor pickup rate to be above 30% (the liquor pickup rate refers to the proportion of the mixed solution in the total weight of the polyurethane ultrafine fiber synthetic leather), and then drying to cure the mixed solution, forming a curing film inside the polyurethane ultrafine fiber synthetic leather, and obtaining the low-odor ultrafine fiber synthetic leather;

[0025] The mixed solution is the odor remover as described in any one of the above.

[0026] As a preferred technical solution:

[0027] A preparation method of a low-odor ultra-fine fiber synthetic leather as described above, the liquor ratio after padding is 30-60%. If the liquor ratio of the mixed liquid in the ultra-fine fiber leather is lower than 30%, the amount of the active ingredient of the deodorant attached to the ultra-fine fiber leather is too small to effectively reduce the odor of the ultra-fine fiber leather; if the liquor ratio of the deodorant in the ultra-fine fiber leather is higher than 60%, although the amount of the active ingredient of the deodorant attached to the ultra-fine fiber leather is too large and is beneficial to reducing the odor of the ultra-fine fiber leather, the handle of the finally treated ultra-fine fiber leather will become significantly hard, thus affecting the quality of the ultra-fine fiber leather.

[0028] A preparation method of a low-odor ultra-fine fiber synthetic leather as described above, the drying temperature is 130-160 °C, and the time is 1-5 min. At different drying temperatures, the drying time should be selected considering controlling the reaction degree of the system to ensure that the contents of the remaining end groups and carboxyl groups meet the requirements.

[0029] For the odor test of the low-odor ultra-fine fiber synthetic leather, the odor test results are: the total value of benzene series is 0.01-0.068 mg / m 3 , the total value of C1-C6 aldehydes is 0.016-0.091 mg / m 3 , the total value of amine compounds is 0.022-0.093 mg / m 3 .

[0030] The principle of the present invention is:

[0031] The three substances of ammonia, aldehydes and toluene existing in the ultra-fine fiber leather are the main components causing unpleasant odors to the human body. These substances are adsorbed by the ultra-fine fibers. At high temperatures, the small-molecule substances adsorbed on the ultra-fine fibers desorb from the fibers, resulting in the deterioration of the air environment in the vehicle. To solve this technical problem, a deodorant for polyurethane ultra-fine fiber synthetic leather provided by the present invention includes deionized water, difunctional amino acids, trifunctional amino acids and carbodiimide.

[0032] The present invention uses the deodorant to react under specific conditions to form a crosslinked cured film on the fiber surface to block the desorption of small molecules from the inside of the ultra-fine fibers at high temperatures.

[0033] The deodorant is impregnated into the ultra-fine fiber leather by being configured into a solution, and then crosslinking and curing are carried out. Polyamide (PA6) is a common ultra-fine fiber raw material for ultra-fine fiber leather. When carbodiimide is used as an activator, when reaching the appropriate reaction temperature, the self-polymerization of amino acids (including trifunctional amino acids and difunctional amino acids) is triggered. The trifunctional amino acid is used as a crosslinking agent for the reaction system. The active groups of the trifunctional amino acid and the difunctional amino acid, amino or carboxyl, react to form amide bonds. The product of the reaction process has good affinity with polyamide and is easy to form a crosslinked network cured film on the fiber surface.

[0034] In the design process of the deodorant, the stability of the deodorant system is crucial. Since amino compounds and carboxyl compounds are added simultaneously, the amino compounds may react with the carboxyl group first and lose their active groups. Therefore, it is necessary to find a substance that can keep the active groups of amino and carboxyl relatively stable at room temperature. Amino acids have been proven in experiments to achieve the above effect. In amino acids, there are both active groups of carboxyl and amino, and at room temperature, the amino and carboxyl groups of amino acid molecules do not undergo self-polymerization reaction.

[0035] The mass fraction of difunctional amino acids in the deodorant should be controlled within 30 parts (per 1000 parts of deionized water). Otherwise, the hand feeling of the microfiber leather will become significantly hard and rigid, and the microfiber leather will lose its softness of leather. At the same time, it should be at least more than 1 part, otherwise sufficient curing crosslinking cannot be obtained.

[0036] As a carboxyl activator, carbodiimide is mainly used to activate the carboxyl group in amino acids and promote the formation of amides and esters. Carbodiimide is used to promote the reaction between difunctional amino acids and trifunctional amino acids to form crosslinked molecules to solidify toluene on the surface of microfiber leather.

[0037] The molar ratio of trifunctional amino acids is 0.34 - 2 times that of difunctional amino acids. By controlling the ratio of trifunctional amino acids to difunctional amino acids, the crosslinking point density can be controlled. Too low ratio will lead to insufficient crosslinking points, and then the barrier property of the cured film to harmful substances will be weak. Too high ratio will lead to the cured product being too hard, affecting the softness of the microfiber leather, and even making the microfiber leather harden and unable to be used in the fields of shoes or automotive interiors.

[0038] The molar ratio of carbodiimide to difunctional amino acids is 0.1 - 1 times. The curing of the deodorant is controlled by the ratio and process of carbodiimide and difunctional amino acids. Too low ratio will lead to low reaction efficiency between difunctional amino acids and trifunctional amino acids, resulting in a large amount of free amino acids, which cannot react in time to form amide bonds and attach to the microfibers, and cannot play a curing role. Too high ratio will lead to an excess of carbodiimide, and a large amount of unreacted carbodiimide will be free in the microfiber leather, resulting in waste. Too low temperature or too short time will lead to insufficient reaction degree, and too high temperature will lead to overreaction, resulting in too low concentration of terminal amino and terminal carboxyl groups of the cured product, and affecting its reaction with ammonia and aldehyde.

[0039] The barrier property of the cured film is relative. That is, the cured film hinders the removal of small molecules, but cannot completely shield the small molecules inside the fiber. In a set of comparative experiments, it was found that the cured film with high-end amino and carboxyl group contents had significantly better effects than the amino acid cured film with low-end amino and carboxyl group contents. We speculate that it is related to the release concentration of gases in the fiber at high temperatures. A large amount of ammonia and aldehydes diffuse towards the fiber surface at high temperatures. When the cured film contains high-end amino and carboxyl group contents, it reacts with ammonia and aldehydes in the mixed gas, reducing the amount of diffused gas, enabling the cured film to effectively block the outward diffusion of gases. Eventually, it is manifested that the toluene release amount of the cured film with high-end amino and carboxyl group contents is low, and basically no ammonia and aldehydes are released. On the contrary, if a large amount of ammonia and aldehydes are not reacted, the barrier property of the cured film cannot effectively block the outward diffusion of a large amount of gases. Eventually, it is manifested that the toluene release amount of the cured film with low-end amino and carboxyl group contents is relatively high, and there is also the release of ammonia and aldehydes.

[0040] Therefore, the present invention needs to control the reaction degree of crosslinking curing to ensure the remaining concentration of terminal amino and carboxyl groups in the system after the reaction ends.

[0041] Amino acids need to be dissolved in a certain solvent to achieve the above reactions. On the one hand, it can dilute the distribution density of amino acids and achieve uniform mixing and dispersion with other components; on the other hand, in the form of a solution, it can achieve impregnation of the fabric. Compared with other organic solvents, water itself has no odor and does not affect the performance of the superfine fiber leather, so it is an optimal dispersion medium.

[0042] The deionized water described in the present invention is water of EW-V grade or better than EW-V grade that meets the requirements of GB / T1146.1-1997 standard. Experiments have found that the ions in water affect the stability of the effective components of the deodorant. For example, some amino acids contain hydroxyl groups and will undergo chemical reactions with amino groups in water with more sodium ions, thus consuming the effective components in the deodorant.

[0043] The deodorant described above can be obtained by mixing the above-mentioned substance components according to conventional physical methods and stirring evenly. Amino acids can be stably stored at room temperature. Those skilled in the art can complete the relevant mixing and stirring work according to their own experience or common sense.

[0044] Beneficial effects

[0045] (1) A deodorant of the present invention uses odorless amino acids as an eliminator for the odor of superfine fiber leather, which can chemically react with ammonia and aldehydes to generate stable amide odorless substances, thereby eliminating the influence of ammonia and aldehydes on the odor of superfine fiber leather;

[0046] (2) An odor eliminator of the present invention activates amino acids by adding carbodiimide as a carboxyl activator and adding trifunctional amino acids as crosslinking agents to form crosslinked compounds, and solidifies small molecules such as toluene attached to ultrafine fibers on the fibers;

[0047] (3) The surface of a low-odor ultrafine fiber synthetic leather of the present invention has a solidified film, which can react with the gas emitted by the ultrafine fiber synthetic leather, thereby making it low-odor;

[0048] (4) The preparation method of a low-odor ultrafine fiber synthetic leather of the present invention is simple. Specific embodiments

[0049] 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 not 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 also fall within the scope defined by the appended claims of this application.

[0050] The term "ultra-fine leather" generally refers to conventional products that use sea-island fiber non-woven fabrics as the fiber skeleton structure, impregnate and solidify polyurethane, and then use the fiber-opening method to dissolve the sea phase in the sea-island fibers, including untreated ultra-fine base fabrics or finished ultra-fine leather products after post-treatment.

[0051] The term "residue" refers to the part of the monomer that enters the polymer through polymerization reaction. For example, when the monomer difunctional amino acid self-polymerizes into the molecular chain, the difference in structure between the monomer difunctional amino acid and the difunctional amino acid residue in the molecular chain is that the active end group changes from an amino group or an acid group to a part of the amide bond.

[0052] The test / calculation methods involved in the specific embodiments are as follows:

[0053] Crosslinking degree: Weigh the weight M1 of the ultra-fine leather before treatment and the weight M2 of the ultra-fine leather after treatment with the odor eliminator respectively after drying, and calculate the weight of the solidified film: M 固化膜 = M2 - M1; The linear amino acid polymer can be dissolved in isopropanol, while the crosslinked amino acid polymer is insoluble in isopropanol. In an isopropanol solution at 75 °C, extract the ultra-fine leather treated with the odor eliminator for 1 hour, filter out the residue, dry and weigh M3, and calculate the weight of the crosslinked polymer in the solidified film: M 交联聚合物 = M3 - M1; Divide the weight of the remaining crosslinked polymer by the weight of the solidified film to obtain the crosslinking degree of the solidified film, and the crosslinking degree = ((M3 - M1) / (M2 - M1)) × 100%.

[0054] Terminal amino group concentration: Determined by the 2,4-dinitrofluorobenzene (FDNB) method: Weigh the weight M1 of the microfiber leather before treatment and the weight M2 of the microfiber leather after treatment with the deodorant separately after drying, and calculate the weight of the cured film: M 固化膜 = M2 - M1; Add the microfiber leather test sample (microfiber leather after treatment with the deodorant) to the mixed solution composed of the ethanol solution of FDNB and the saturated sodium bicarbonate aqueous solution (pH = 8.0 - 9.0), where the mass ratio of ethanol to the saturated sodium bicarbonate aqueous solution is 1:3, and then reflux and react in a constant temperature water bath at 100 °C for 48 hours until the heterogeneous derivatization reaction is complete, so that the remaining terminal amino groups in the reaction system are grafted with DNP groups; Hydrolyze the microfiber leather sample of the cured film polymer derivative containing DNP groups after the reaction in 6 mol / L HCl at 105 °C for 48 hours to generate DNP-amino acids and other free amino acids. Stir and dissolve the hydrolysis product in ether, remove the insoluble matter through filter paper, and then obtain DNP-amino acids by vacuum distillation; Dissolve DNP-amino acids in water, titrate the carboxyl group of DNP-amino acids with standard NaOH to obtain the molar amount (N0) of DNP-amino acids. The molar amount of NaOH consumed in the titration process is equal to the molar amount of DNP-amino acids, the molar amount of DNP-amino acids is equal to the molar amount of terminal amino groups, the mass of the terminal amino groups of the cured film polymer = 16 * N0, and the concentration of terminal amino groups is: (16N0 / M 固化膜 ) × 10 6 ppm / kg.

[0055] Terminal carboxyl group concentration: Determined by the carboxypeptidase hydrolysis method. Weigh the weight M1 of the microfiber leather before treatment and the weight M2 of the microfiber leather after treatment with the deodorant separately after drying, and calculate the weight of the cured film: M 固化膜 = M2 - M1; After crushing the microfiber leather test sample with a grinder, add it to the 1% aqueous solution of carboxypeptidase Y. The weight ratio of the microfiber leather test sample to the aqueous solution of carboxypeptidase Y is 1:100, and then stir the aqueous solution of carboxypeptidase Y with the microfiber leather test sample added at a speed of 1000 revolutions per minute at 37 °C until the reaction hydrolysis is sufficient. After reacting for 1000 hours, the amino acids containing terminal carboxyl groups are hydrolyzed from the cured film and become amino acid monomers again. Add the amino acid monomers to the mixed solution composed of the ethanol solution of FDNB and the saturated sodium bicarbonate aqueous solution, where the mass ratio of ethanol to the saturated sodium bicarbonate solution is 1:3. React the amino group of the amino acid with FDNB, and then titrate the carboxyl group of the amino acid with standard NaOH to obtain the molar amount (N1) of DNP-amino acids. The molar amount of NaOH consumed in the titration process is equal to the molar amount of DNP-amino acids, the molar amount of DNP-amino acids is equal to the molar amount of terminal carboxyl groups, and the mass of the terminal carboxyl groups of the cured film polymer = 45 * N1. The concentration of terminal carboxyl groups is: (45 * N1 / M 固化膜)×10 6 ppm / kg。

[0056] Odor test: Cut a 4m 2 low-odor microfiber synthetic leather for odor test. Collect gas for 30 min with a sample bag with an inflation volume of 50%, where the sample bag volume is 2000 L, the capture capacity is 3 L, and the capture speed is 100 mL / min; then test for 2 h at 65 °C, and determine the total value of benzene compounds by gas chromatography-mass spectrometry (Agilent's 7890B-5977A instrument), determine the total value of amine compounds by gas chromatography and mass spectrometry equipment (semi-quantitative, calculated based on toluene), and determine the total value of C1-C6 aldehydes by liquid chromatography (Agilent's 1260 instrument).

[0057] Softness: Determined according to DIN EN ISO 17235, and the test environment diameter is 25 mm.

[0058] In the examples and comparative examples, the low-odor treated superfine leather used is the superfine leather XG with the model specification sold by Shanghai Huafeng Superfiber Technology Co., Ltd.; the odor test results of the superfine leather sample before using the low-odor treatment process are as follows: the total value of benzene compounds is 0.089 mg / m 3 and the total value of C1-C6 aldehydes is 0.152 mg / m 3 and the total value of amine compounds is 0.151 mg / m 3 *kg; the measured softness value is 3.8 mm.

[0059] Example 1

[0060] A preparation method of a low-odor microfiber synthetic leather, the specific steps are as follows:

[0061] (1) Preparation of raw materials:

[0062] Polyurethane microfiber synthetic leather, and the microfiber material in the microfiber synthetic leather is polyamide;

[0063] Deionized water (water of EW-V grade meeting the requirements of GB / T1146.1-1997 standard);

[0064] Difunctional amino acid: glycine, with a molar mass of 75 g / mol;

[0065] Trifunctional amino acid: lysine, with a molar mass of 115 g / mol;

[0066] Carbodiimide: N,N'-diisopropylcarbodiimide, with a molar mass of 126 g / mol;

[0067] (2) Mix deionized water, bifunctional amino acid, trifunctional amino acid and carbodiimide and stir evenly to prepare a mixed solution, namely the deodorant;

[0068] Among them, the mass ratio of deionized water to bifunctional amino acid is 1000:30; the amount of substance of trifunctional amino acid (i.e.) is 2 times that of bifunctional amino acid; the amount of substance of carbodiimide is 1 time that of bifunctional amino acid;

[0069] (3) Immerse the polyurethane microfiber synthetic leather into the mixed solution in step (2), and by means of padding, control the liquor pickup rate at 60%, and then dry it at 130°C for 5 minutes to obtain the low-odor microfiber synthetic leather.

[0070] On the surface of the microfibers inside the obtained low-odor microfiber synthetic leather, there is a cured film (formed by curing the mixed solution during drying). The cured film is composed of bifunctional amino acid residues, trifunctional amino acid residues and carbodiimide residues. The bifunctional amino acid residues and trifunctional amino acid residues are connected by amide bonds. The carbodiimide residues are connected to the bifunctional amino acid residues and trifunctional amino acid residues by amide bonds; the crosslinking degree of the cured film is 100%; the terminal amino group concentration in the cured film is 1000 ppm / kg, and the terminal carboxyl group concentration is 210 ppm / kg; in the low-odor microfiber synthetic leather, the mass ratio of the cured film is 10.34%; conduct an odor test on the low-odor microfiber synthetic leather, and the total value of benzene series is measured to be 0.01 mg / m 3 , the total value of C1-C6 aldehydes is 0.016 mg / m 3 , the total value of amine compounds is 0.07 mg / m 3 ; the softness of the low-odor microfiber synthetic leather is 3.3 mm.

[0071] Example 2

[0072] A preparation method of low-odor microfiber synthetic leather, the specific steps are as follows:

[0073] (1) Preparation of raw materials:

[0074] Polyurethane microfiber synthetic leather, the material of the microfibers in the microfiber synthetic leather is polyamide;

[0075] Deionized water (water of EW-V grade meeting the requirements of GB / T1146.1-1997 standard);

[0076] Bifunctional amino acid: valine, its molar mass is 117 g / mol;

[0077] Trifunctional amino acid: lysine, its molar mass is 115 g / mol;

[0078] Carbodiimide: Dicyclohexylcarbodiimide, with a molar mass of 206 g / mol;

[0079] (2) Mix deionized water, difunctional amino acid, trifunctional amino acid and carbodiimide and stir evenly to prepare a mixed solution, which is the deodorant;

[0080] Among them, the mass ratio of deionized water to difunctional amino acid is 1000:20; the amount of substance of trifunctional amino acid is 1.2 times that of difunctional amino acid; the amount of substance of carbodiimide is 0.5 times that of difunctional amino acid;

[0081] (3) Immerse the polyurethane ultrafine fiber synthetic leather into the mixed solution in step (2), and control the liquor pickup rate at 35% by padding, and then dry it at 135°C for 5 minutes to obtain the low-odor ultrafine fiber synthetic leather.

[0082] On the surface of the ultrafine fibers inside the obtained low-odor ultrafine fiber synthetic leather, there is a cured film (formed by curing the mixed solution during drying). The cured film is composed of difunctional amino acid residues, trifunctional amino acid residues and carbodiimide residues. The difunctional amino acid residues and trifunctional amino acid residues are connected by amide bonds, and the carbodiimide residues are connected to the difunctional amino acid residues and trifunctional amino acid residues by amide bonds; the crosslinking degree of the cured film is 87%; the terminal amino group concentration in the cured film is 347 ppm / kg, and the terminal carboxyl group concentration is 548 ppm / kg; in the low-odor ultrafine fiber synthetic leather, the mass ratio of the cured film is 2.14%; conduct an odor test on the low-odor ultrafine fiber synthetic leather, and the total value of benzene is measured to be 0.029 mg / m 3 , the total value of C1-C6 aldehydes is 0.065 mg / m 3 , the total value of amine compounds is 0.037 mg / m 3 ; the softness of the low-odor ultrafine fiber synthetic leather is 3.6 mm.

[0083] Example 3

[0084] A preparation method of low-odor ultrafine fiber synthetic leather, the specific steps are as follows:

[0085] (1) Preparation of raw materials:

[0086] Polyurethane ultrafine fiber synthetic leather, and the material of the ultrafine fibers in the ultrafine fiber synthetic leather is polyamide;

[0087] Deionized water (water of EW-V grade meeting the requirements of GB / T1146.1-1997 standard);

[0088] Difunctional amino acid: Leucine, with a molar mass of 131 g / mol;

[0089] Trifunctional amino acid: Arginine, with a molar mass of 174 g / mol;

[0090] Carbodiimide: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (CAS No.: 25952-53-8) with a molar mass of 191 g / mol;

[0091] (2) Mix deionized water, bifunctional amino acid, trifunctional amino acid, and carbodiimide and stir evenly to prepare a mixed solution, which is the deodorant;

[0092] Among them, the mass ratio of deionized water to bifunctional amino acid is 1000:15; the amount of substance of the trifunctional amino acid is 0.5 times that of the bifunctional amino acid; the amount of substance of the carbodiimide is 0.2 times that of the bifunctional amino acid;

[0093] (3) Immerse the polyurethane microfiber synthetic leather into the mixed solution in step (2), and by the padding method, control the liquor pickup rate at 40%, and then dry it at 140 °C for 4 min to obtain a low-odor microfiber synthetic leather.

[0094] On the surface of the microfibers inside the obtained low-odor microfiber synthetic leather, there is a cured film (formed by the curing of the mixed solution during drying). The cured film is composed of bifunctional amino acid residues, trifunctional amino acid residues, and carbodiimide residues. The bifunctional amino acid residues and trifunctional amino acid residues are connected by amide bonds, and the carbodiimide residues are connected to the bifunctional amino acid residues and trifunctional amino acid residues by amide bonds; the crosslinking degree of the cured film is 74%; the concentration of terminal amino groups in the cured film is 301 ppm / kg, and the concentration of terminal carboxyl groups is 80 ppm / kg; in the low-odor microfiber synthetic leather, the mass ratio of the cured film is 1.17%; for the odor test of the low-odor microfiber synthetic leather, the total value of benzene compounds is 0.054 mg / m 3 , the total value of C1-C6 aldehydes is 0.071 mg / m 3 , the total value of amine compounds is 0.093 mg / m 3 ; the softness of the low-odor microfiber synthetic leather is 3.7 mm.

[0095] Example 4

[0096] A preparation method of a low-odor microfiber synthetic leather, the specific steps are as follows:

[0097] (1) Preparation of raw materials:

[0098] Polyurethane microfiber synthetic leather, the material of the microfibers in the microfiber synthetic leather is polyamide;

[0099] Deionized water (water of EW-V grade meeting the requirements of GB / T1146.1-1997 standard);

[0100] Difunctional amino acid: phenylalanine, with a molar mass of 165 g / mol;

[0101] Trifunctional amino acid: aspartic acid, with a molar mass of 133 g / mol;

[0102] Carbodiimide: N,N'-diisopropylcarbodiimide, with a molar mass of 126 g / mol;

[0103] (2) Mix deionized water, difunctional amino acid, trifunctional amino acid and carbodiimide and stir evenly to prepare a mixed solution, which is the deodorant;

[0104] Among them, the mass ratio of deionized water to difunctional amino acid is 1000:1; the amount of substance of trifunctional amino acid is 0.34 times that of difunctional amino acid; the amount of substance of carbodiimide is 0.1 times that of difunctional amino acid;

[0105] (3) Immerse the polyurethane microfiber synthetic leather into the mixed solution in step (2), and control the liquid holding rate at 30% by padding, and then dry it at 145 °C for 3 min to obtain a low-odor microfiber synthetic leather.

[0106] On the surface of the microfibers inside the obtained low-odor microfiber synthetic leather, there is a cured film (formed by curing the mixed solution during drying). The cured film is composed of difunctional amino acid residues, trifunctional amino acid residues and carbodiimide residues. The difunctional amino acid residues and trifunctional amino acid residues are connected by amide bonds, and the carbodiimide residues are connected to the difunctional amino acid residues and trifunctional amino acid residues by amide bonds; the crosslinking degree of the cured film is 70%; the concentration of terminal amino groups in the cured film is 200 ppm / kg, and the concentration of terminal carboxyl groups is 118 ppm / kg; in the low-odor microfiber synthetic leather, the mass ratio of the cured film is 0.04%; conduct an odor test on the low-odor microfiber synthetic leather, and the total value of benzene is measured to be 0.066 mg / m 3 , the total value of C1-C6 aldehydes is 0.081 mg / m 3 , the total value of amine compounds is 0.081 mg / m 3 ; the softness of the low-odor microfiber synthetic leather is 3.8 mm.

[0107] Comparative Example 1

[0108] A preparation method of microfiber synthetic leather is basically the same as that in Example 4, except that the amount of substance of trifunctional amino acid in step (2) is 3 times that of difunctional amino acid.

[0109] In the prepared ultra-fine fiber synthetic leather, the crosslinking degree of the curing film is 100%; the concentration of terminal amino groups in the curing film is 1000 ppm / kg, and the concentration of terminal carboxyl groups is 32 ppm / kg; the mass ratio of the curing film is 13.1%; the softness of the ultra-fine fiber synthetic leather is 2.5 mm.

[0110] Comparing Comparative Example 1 with Example 4, the softness of Comparative Example 1 decreases and the handfeel is rigid. This is because the proportion of trifunctional amino acids is too large, resulting in an excessive density of crosslinking points, which causes the synthetic leather to finally lose its handfeel.

[0111] Example 5

[0112] A preparation method of a low-odor ultra-fine fiber synthetic leather is as follows:

[0113] (1) Preparation of raw materials:

[0114] Polyurethane ultra-fine fiber synthetic leather, and the material of the ultra-fine fibers in the ultra-fine fiber synthetic leather is polyamide;

[0115] Deionized water (water of EW-V grade meeting the requirements of GB / T 1146.1-1997 standard);

[0116] Difunctional amino acid: serine, with a molar mass of 105 g / mol;

[0117] Trifunctional amino acid: lysine, with a molar mass of 115 g / mol;

[0118] Carbodiimide: dicyclohexylcarbodiimide, with a molar mass of 206 g / mol;

[0119] (2) Mix deionized water, difunctional amino acid, trifunctional amino acid and carbodiimide and stir evenly to prepare a mixed solution, that is, an odor remover;

[0120] Among them, the mass ratio of deionized water to difunctional amino acid is 1000:25; the amount of substance of trifunctional amino acid is 1.6 times that of difunctional amino acid; the amount of substance of carbodiimide is 0.8 times that of difunctional amino acid;

[0121] (3) Immerse the polyurethane ultra-fine fiber synthetic leather in the mixed solution in step (2), and by means of padding, control the liquor pickup rate at 50%, and then dry it at 150 °C for 2 min to obtain a low-odor ultra-fine fiber synthetic leather.

[0122] The surface of the ultrafine fibers inside the obtained low-odor ultrafine fiber synthetic leather is covered with a cured film (formed by curing the mixed solution during drying). The cured film is composed of bifunctional amino acid residues, trifunctional amino acid residues, and carbodiimide residues. The bifunctional amino acid residues and trifunctional amino acid residues are connected by amide bonds, and the carbodiimide residues are connected to the bifunctional amino acid residues and trifunctional amino acid residues by amide bonds; the crosslinking degree of the cured film is 95%; the concentration of terminal amino groups in the cured film is 876 ppm / kg, and the concentration of terminal carboxyl groups is 469 ppm / kg; in the low-odor ultrafine fiber synthetic leather, the mass ratio of the cured film is 5.40%; for the odor test of the low-odor ultrafine fiber synthetic leather, the total value of benzene is 0.021 mg / m 3 , and the total value of C1-C6 aldehydes is 0.031 mg / m 3 , and the total value of amine compounds is 0.043 mg / m 3 , and the softness of the low-odor ultrafine fiber synthetic leather is 3.5 mm.

[0123] Example 6

[0124] A preparation method of a low-odor ultrafine fiber synthetic leather is as follows:

[0125] (1) Preparation of raw materials:

[0126] Polyurethane ultrafine fiber synthetic leather, and the material of the ultrafine fibers in the ultrafine fiber synthetic leather is polyamide;

[0127] Deionized water (water of EW-V grade meeting the requirements of GB / T 1146.1-1997 standard);

[0128] Bifunctional amino acid: asparagine (molar mass of 132 g / mol) and glutamine (molar mass of 146 g / mol) with a molar ratio of 1:1;

[0129] Trifunctional amino acid: aspartic acid (molar mass of 133 g / mol);

[0130] Carbodiimide: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (CAS No.: 25952-53-8) with a molar mass of 191 g / mol;

[0131] (2) Mix deionized water, bifunctional amino acid, trifunctional amino acid, and carbodiimide and stir evenly to prepare a mixed solution, that is, the deodorant;

[0132] Among them, the mass fraction ratio of deionized water to bifunctional amino acid is 1000:10; the amount of substance of the trifunctional amino acid is 0.8 times that of the bifunctional amino acid; the amount of substance of the carbodiimide is 0.3 times that of the bifunctional amino acid;

[0133] (3) Immerse the polyurethane microfiber synthetic leather into the mixed solution of step (2), and by means of padding, control the liquor pickup rate at 55%, and then dry it at 155 °C for 1 min to obtain the low-odor microfiber synthetic leather.

[0134] On the surface of the microfibers inside the obtained low-odor microfiber synthetic leather, there is a cured film (formed by the curing of the mixed solution during drying). The cured film is composed of bifunctional amino acid residues, trifunctional amino acid residues and carbodiimide residues. The bifunctional amino acid residues and trifunctional amino acid residues are connected by amide bonds, and the carbodiimide residues are connected to the bifunctional amino acid residues and trifunctional amino acid residues by amide bonds; the crosslinking degree of the cured film is 77%; the concentration of terminal amino groups in the cured film is 364 ppm / kg, and the concentration of terminal carboxyl groups is 1000 ppm / kg; in the low-odor microfiber synthetic leather, the mass ratio of the cured film is 1.20%; conduct an odor test on the low-odor microfiber synthetic leather, and the total value of benzene series is measured to be 0.051 mg / m 3 , the total value of C1-C6 aldehydes is 0.053 mg / m 3 , the total value of amine compounds is 0.022 mg / m 3 , the softness of the low-odor microfiber synthetic leather is 3.7 mm.

[0135] Example 7

[0136] A preparation method of a low-odor microfiber synthetic leather, the specific steps are as follows:

[0137] (1) Preparation of raw materials:

[0138] Polyurethane microfiber synthetic leather, and the material of the microfibers in the microfiber synthetic leather is polyamide;

[0139] Deionized water (water of EW-V grade meeting the requirements of GB / T1146.1-1997 standard);

[0140] Bifunctional amino acids: threonine (molar mass of 119 g / mol) and histidine (molar mass of 155 g / mol) with a molar ratio of 2:1;

[0141] Trifunctional amino acids: lysine and arginine with a molar ratio of 1:1;

[0142] Carbodiimide: N,N'-diisopropylcarbodiimide and dicyclohexylcarbodiimide with a molar ratio of 1:1;

[0143] (2) Mix deionized water, bifunctional amino acids, trifunctional amino acids and carbodiimide and stir evenly to prepare a mixed solution, that is, the deodorant.

[0144] Among them, the mass ratio of deionized water to bifunctional amino acid is 1000:12; the amount of substance of trifunctional amino acid is 1 times that of bifunctional amino acid; the amount of substance of carbodiimide is 0.6 times that of bifunctional amino acid;

[0145] (3) Immerse the polyurethane microfiber synthetic leather into the mixed solution in step (2), and by means of padding, control the liquor pickup rate at 45%, and then dry it at 160 °C for 1 min to obtain the low-odor microfiber synthetic leather.

[0146] On the surface of the microfibers inside the obtained low-odor microfiber synthetic leather, there is a cured film covered (formed by curing of the mixed solution during drying). The cured film is composed of bifunctional amino acid residues, trifunctional amino acid residues and carbodiimide residues. The bifunctional amino acid residues and trifunctional amino acid residues are connected by amide bonds, and the carbodiimide residues are connected to the bifunctional amino acid residues and trifunctional amino acid residues by amide bonds; the crosslinking degree of the cured film is 84%; the terminal amino group concentration in the cured film is 616 ppm / kg, and the terminal carboxyl group concentration is 371 ppm / kg; in the low-odor microfiber synthetic leather, the mass ratio of the cured film is 1.55%; conduct an odor test on the low-odor microfiber synthetic leather, and the total value of benzene series is measured to be 0.032 mg / m 3 , the total value of C1-C6 aldehydes is 0.044 mg / m 3 , the total value of amine compounds is 0.053 mg / m 3 , and the softness of the low-odor microfiber synthetic leather is 3.6 mm.

[0147] Example 8

[0148] A preparation method of low-odor microfiber synthetic leather is basically the same as that in Example 4, the only difference is that the drying temperature in step (3) is adjusted to 160 °C, so that the terminal amino group concentration in the cured film is 52 ppm / kg and the terminal carboxyl group concentration is 40 ppm / kg.

[0149] In the obtained microfiber synthetic leather, the crosslinking degree of the cured film is 70%; the mass ratio of the cured film is 0.04%; conduct an odor test on the microfiber synthetic leather, and the total value of benzene series is measured to be 0.068 mg / m 3 , the total value of C1-C6 aldehydes is 0.091 mg / m 3 , the total value of amine compounds is 0.093 mg / m 3 ; the softness of the microfiber synthetic leather is 3.7 mm.

[0150] Comparing Example 8 with Example 4, the odor test result of Example 8 is poor because, compared with Example 4, in addition to blocking the large overflow of harmful substances through the cured film at high temperatures, there are sufficient active terminal amino groups and terminal carboxyl groups on the cured film, which can react with aldehyde and amine compounds respectively and be converted into a part of the molecular chain of the cured film. The low concentrations of terminal amino groups and terminal carboxyl groups in Example 8 result in insufficient conversion of aldehyde and amine compounds. When the gas overflow pressure further increases, it will also affect the increase in the total value of benzene compounds.

[0151] Comparative Example 2

[0152] A preparation method of an ultrafine fiber synthetic leather is basically the same as that of Example 8, except that the amount of substance of the trifunctional amino acid in step (2) is 0.2 times that of the bifunctional amino acid.

[0153] In the prepared ultrafine fiber synthetic leather, the crosslinking degree of the cured film is 62%; the concentration of terminal amino groups in the cured film is 200 ppm / kg, and the concentration of terminal carboxyl groups is 401 ppm / kg; the mass ratio of the cured film is 0.04%; the odor of the ultrafine fiber synthetic leather is tested, and the total value of benzene compounds is measured to be 0.078 mg / m 3 , the total value of C1 - C6 aldehydes is 0.092 mg / m 3 , and the total value of amine compounds is 0.095 mg / m 3 ; the softness is 2.5 mm.

[0154] Comparing Comparative Example 2 with Example 8, the input ratio of the trifunctional amino acid in Comparative Example 2 is too small, resulting in a decrease in the crosslinking degree, and further weakening the ability of the cured film to block the overflow of harmful substances at high temperatures, and the effect of reducing the release amount of harmful substances is not good.

Claims

1. A low-odor microfiber synthetic leather, characterized by: The surface of the microfiber inside the low-odor microfiber synthetic leather is covered with a layer of cured film; The cured film comprises a difunctional amino acid residue, a trifunctional amino acid residue and a carbodiimide residue, wherein the difunctional amino acid residue and the trifunctional amino acid residue are connected by an amide bond, and the carbodiimide residue and the difunctional amino acid residue and the trifunctional amino acid residue are connected by an amide bond; the amount of the trifunctional amino acid residue is 0.34 to 2 times that of the difunctional amino acid residue; and the amount of the carbodiimide residue is 0.1 to 1 times that of the difunctional amino acid residue. The crosslinking degree of the cured film is greater than 70%; The terminal amino group concentration in the cured film is not less than 200 ppm / kg, and the terminal carboxyl group concentration is not less than 80 ppm / kg; the terminal amino group concentration and the terminal carboxyl group concentration in the cured film are both not higher than 1000 ppm / kg; The mass proportion of the cured film in the low-odor microfiber synthetic leather is 0.04 to 10.34%; The material of the ultrafine fibers in the low-odor ultrafine fiber synthetic leather is polyamide.

2. A deodorant for use in the manufacturing process of a low-odor microfiber synthetic leather according to claim 1, characterized in that: The deodorant comprises deionized water, difunctional amino acid, trifunctional amino acid and carbodiimide; The mass ratio of deionized water to difunctional amino acid is 1000:1-30; The amount of trifunctional amino acids is 0.34 to 2 times that of difunctional amino acids; The amount of carbodiimide is 0.1 to 1 times that of the difunctional amino acid.

3. The deodorant according to claim 2, characterized in that The difunctional amino acid is one or more of glycine, valine, leucine, phenylalanine, serine, asparagine, glutamine, threonine and histidine.

4. The deodorant according to claim 2, characterized in that The trifunctional amino acid is one or more of aspartic acid, lysine and arginine.

5. The deodorant according to claim 2, characterized in that The carbodiimide is one or more of N,N′-diisopropylcarbodiimide, dicyclohexylcarbodiimide, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride.

6. The method for preparing low-odor microfiber synthetic leather according to claim 1, wherein: The polyurethane microfiber synthetic leather is immersed in the mixed liquid, and the liquid carrying rate is controlled to be above 30% by dipping, and then the mixed liquid is solidified by drying to form a solidified film inside the polyurethane microfiber synthetic leather to obtain a low-odor microfiber synthetic leather; The mixed liquid is the deodorant according to any one of claims 2 to 5.

7. The method for preparing low-odor microfiber synthetic leather according to claim 6, characterized in that: The liquid carrying rate after immersion is 30-60%.

8. The method for preparing low-odor microfiber synthetic leather according to claim 6, characterized in that: The drying temperature is 130-160°C and the drying time is 1-5 minutes.