A hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin and its preparation method and application

Abstract

The present invention belongs to the field of functional polyurethane materials for ultrafine fiber synthetic leather, and relates to a polyurethane resin for ultrafine fiber with hydrolysis resistance to toluene reduction and suede dyeing, and a preparation method and application thereof. A polyurethane resin for ultrafine fiber with hydrolysis resistance to toluene reduction and suede dyeing, comprising the following components by weight: polypropylene carbonate polyol: 17.72-18.52 parts; bio-based gel protein powder: 1-2 parts; antioxidant: 0.02 parts; phosphoric acid H 3 PO 4 : 0.003 parts; catalyst: 0.002 parts; ethylene glycol EG: 1.54-1.75 parts; 4,4-diphenylmethane diisocyanate MDI: 8.09-8.39 parts; anti-viscosity reducing agent: 0.03 parts; methanol CH 3 OH: 0.05 parts; N,N-dimethylformamide DMF: 69-70 parts; auxiliary agent 1 part. The invention solves the problems of poor color fastness, dyeability, levelness and dye penetration of toluene-reduced suede microfiber.

Description

Technical Field

[0001] The invention belongs to the field of functional polyurethane materials for ultrafine fiber synthetic leather, and specifically relates to a polyurethane resin for ultrafine fiber with hydrolysis resistance and toluene reduction suede dyeing, and a preparation method and application thereof. Background Art

[0002] Superfine fiber synthetic leather is a composite material of superfine fiber and polyurethane resin. Due to different fiber manufacturing processes, it is divided into fixed island superfiber and unfixed island superfiber; due to different fiber opening methods, it is divided into alkali-reduced superfiber and toluene-reduced superfiber. The mainstream product on the market is toluene-reduced superfiber, accounting for more than 90%, which is divided into suede superfiber and smooth superfiber. Suede superfiber has excellent appearance, touch and comfort after dyeing and finishing. It is also a true transition from "imitation" to "simulation" of leather in terms of structure and texture. It is a high-end product in the synthetic leather industry and a development trend of new materials in the future. It is widely used in clothing, shoes, sofas, automobiles and other fields.

[0003] The core technology of toluene-reduced suede microfiber is dyeing, which has high requirements on the dyeability, levelness, dye penetration and color fastness of polyurethane resin. If the polyurethane dyeing performance and color fastness are not good, it is easy to have problems such as surface mottling, color migration, and fiber white core. Therefore, various polyurethane companies in the industry are committed to developing and improving polyurethane resins with high dyeing performance for toluene-reduced suede microfiber.

[0004] At present, suede microfiber resin (toluene reduction or alkali reduction) generally has problems with color fastness, dyeing, level dyeing, and poor dyeing permeability. Various research institutions are also committed to improving these problems. For example: China's invention patent CN102746484A mainly selects some chain extenders containing amino groups, and introduces some urea groups into the polyurethane molecular chain through blending reaction with small molecule alcohols ( ), so that the polyurethane resin has a structure similar to that of the fiber, and the chemical bond between the polyurethane resin and the dye molecule is increased, thereby improving the dyeability of the polyurethane resin. However, since the coloring of the polyurethane mainly occurs in the amorphous region of the soft segment of the molecule, the introduction of urea groups is manifested in the hard segment of the polyurethane, which has strong crystallinity and is difficult for dye molecules to enter, and the improvement of the dyeing performance is limited. In addition, the rigidity of the urea group is strong, and excessive introduction will increase the hardness of the product and reduce the fluffy touch of the product surface. Chinese invention patent CN105542108A improves the dyeability of the polyurethane resin by selecting a chain extender and polyetheramine polyol containing an amino group, and by introducing some amide groups, secondary amine groups, and tertiary amine groups into the soft segment and hard segment of the polyurethane. However, the polarity of the soft segment polyetheramine is relatively weak. Although it can improve the dyeing performance of the resin, the color fastness is low and the color is easy to migrate. The selected amine chain extender is expensive and is not suitable for large-scale production. Chinese invention patent CN113881008A, by introducing part of polytetrahydrofuran-ethylene oxide blended polyol into the polyurethane soft segment, by improving the hydrophilicity of the resin, increasing the adsorption of dyes; introducing part of the carboxyl chain extender into the formula to balance the coloring rate of the resin and nylon, thereby increasing the levelness of the resin; however, the introduction of polytetrahydrofuran-ethylene oxide will reduce the hydrolysis resistance of the polyurethane, and its dyeing improvement mechanism is only based on the adsorption of water molecules by the ether bond of ethylene oxide, which is easy to cause uneven surface and internal adsorption, color difference of the skin, and white core; introducing small molecules containing carboxyl side chains into the hard segment of the polyurethane, making the polyurethane resin weakly acidic, reducing the dyeing rate of the polyurethane resin, and balancing the coloring rate of the resin and nylon, and increasing the levelness. However, introducing carboxyl groups into the molecular chain so that part of the polyurethane molecules carry carboxyl anions can improve the hydrophilicity of the resin and reduce the crystallinity of the hard segment, which theoretically increases the dyeing rate of the polyurethane resin. In addition, the introduction of carboxyl groups reduces the crystallinity of the hard segment and the intermolecular forces, which will also relatively reduce the color fastness of the resin. Summary of the invention

[0005] In view of the deficiencies in the above-mentioned prior art, the present invention provides a hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin and a preparation method and application thereof, with the aim of solving the problems of poor color fastness, dyeability, levelness and dye penetration of the current toluene-reduced suede microfiber.

[0006] The specific technical solutions are as follows:

[0007] The first object of the present invention is to provide a hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin, which comprises the following components by weight: polypropylene carbonate polyol: 17.72-18.52 parts; bio-based gel protein powder: 1-2 parts; antioxidant: 0.02 parts; phosphoric acid H 3 PO 4: 0.003 parts; catalyst: 0.002 parts; ethylene glycol EG: 1.54-1.75 parts; 4,4-diphenylmethane diisocyanate MDI: 8.09-8.39 parts; anti-viscosity reducing agent: 0.03 parts; methanol CH 3 OH: 0.05 parts; N,N-dimethylformamide DMF: 69-70 parts; auxiliary agent 1 part.

[0008] Furthermore, the polypropylene carbonate polyol includes polypropylene carbonate diol.

[0009] Furthermore, the polypropylene carbonate diol is an aliphatic polycarbonate diol synthesized from carbon dioxide and propylene oxide, and the reaction equation is as follows:

[0010] .

[0011] Furthermore, the polypropylene carbonate diol is one or two or more of PPCD-222, PPCD-531, and PPCD-242 produced by Huizhou Daya Bay Dazhi Fine Chemical Co., Ltd.; the number average molecular weight of PPCD-222 is 2000 g / mol, the number average molecular weight of PPCD-531 is 3000 g / mol, and the number average molecular weight of PPCD-242 is 4000 g / mol.

[0012] By adopting the above technical scheme, the molecular soft segment polyol of the polyurethane resin provided by the present invention is polypropylene carbonate polyol, which is a new type of material used in ultra-fine fibers, and has both the flexibility of polyether and the rigidity and strength of polycarbonate, and the performances of the two are complementary and mutually beneficial;

[0013] In the present invention, the polypropylene carbonate polyol includes polypropylene carbonate diol, which is widely available and inexpensive, has higher mechanical properties and hydrolysis resistance than polypropylene oxide and polycaprolactone, and has higher cost performance than polycarbonate and polytetrahydrofuran.

[0014] Furthermore, the bio-based gel-type protein powder includes YP901E vegetarian soy protein isolate produced by Shandong Yuwang Industrial (Group) Co., Ltd.

[0015] By adopting the above technical solution, in the present invention, the dyeing group is a bio-based gel-type protein powder, which is a bio-based material. Compared with petroleum-based dyeing materials, it is more environmentally friendly and non-toxic, and has a wide source and a low price.

[0016] Furthermore, the antioxidant includes pentaerythritol tetrakis (3,5-di-tert-butyl-4-hydroxy)benzene propionate (antioxidant 1010); the catalyst includes bismuth neodecanoate, and the bismuth neodecanoate is PUCAT2420 from Hangzhou Jiehui New Materials Co., Ltd.; the anti-viscosity reduction agent includes DL-malic acid (2-hydroxysuccinic acid), and the DL-malic acid is purchased from Jinhu County Tetra Le Biotechnology Industrial Co., Ltd.; the auxiliary agent includes sodium diisooctyl sulfosuccinate, and the sodium diisooctyl sulfosuccinate is S-11 (40% solid content) from Shanghai Rishen Chemical Co., Ltd.

[0017] Further, the molecular structure of the hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin is as follows:

[0018]

[0019] Among them, R is a reactive group such as polypropylene carbonate polyol and chain extender EG, and the spheres are bio-based gel-type protein powder; the surface of the bio-based gel-type protein powder contains a large number of reactive groups such as hydroxyl, amino, and carboxyl groups. The bio-based gel-type protein powder reacts with 4,4-diphenylmethane diisocyanate through its surface reactive groups to form a cross-linked network structure, and the filled bio-based gel-type protein powder is evenly distributed in the molecular gaps of the polyurethane resin.

[0020] The second object of the present invention is to provide a method for preparing the above-mentioned hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin, comprising the following steps:

[0021] First, polypropylene carbonate polyol, the first part of bio-based gel protein powder, antioxidant, H 3 PO 4 and the first part of DMF are fully stirred evenly, and then the first part of MDI is added, and the reaction temperature is controlled to be 70-75°C for constant temperature prepolymerization for 1-2 hours; after the prepolymerization is completed, the second part of MDI is added to increase viscosity, and when the viscosity reaches 40-60Pa.s / 70°C, the second part of DMF and EG are added, and after fully stirring, the remaining MDI is added again, and the temperature is controlled at 70-80°C for reaction and viscosity increase, and a catalyst is added during the viscosity increase process, and the third part of DMF is gradually added to dilute the viscosity until the viscosity reaches 100-120Pas / 25°C, and the remaining DMF and methanol are added for end-capping, the reaction is terminated, and then an anti-viscosity reducing agent, an auxiliary agent and the remaining bio-based gel-type protein powder are added, and after being completely stirred, the mixture is cooled and packaged to finally obtain the hydrolysis-resistant toluene reduced suede dyeing microfiber polyurethane resin.

[0022] Furthermore, after adding the anti-viscosity reducing agent, the auxiliary agent and the bio-based gel protein powder, the stirring temperature is 60-70° C. and the stirring time is 1-2 hours.

[0023] Furthermore, the bio-based gel-type protein powder is added in two parts at a weight ratio of 1:1, the DMF is added in four parts at a weight ratio of (16.4-17.3):(20-20.9):26.1:6, and the MDI is added in three parts at a weight ratio of (18.8-19.2):1:(66.9-105.2).

[0024] Furthermore, the third part of DMF is added in three steps, and the mass of DMF added in each step is equal. The third object of the present invention is to provide the application of the above hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin in the field of toluene-reduced suede microfiber.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention does not use traditional hydrolysis-resistant polyols such as polytetrahydrofuran, polypropylene oxide, polycarbonate, and polycaprolactone, but uses polypropylene carbonate polyol. Polypropylene carbonate is mainly prepared by copolymerization of carbon dioxide and propylene oxide, and has both polycarbonate and polyether structures. It is both rigid and flexible, has a wide range of material sources, is low in cost, and has excellent mechanical properties and hydrolysis resistance.

[0027] (2) The present invention no longer uses the traditional petroleum-based chemical raw materials for improving dyeing performance, but selects bio-based gel-type protein powder with a particle size of less than 100 mesh as the reaction synthetic material. There are a large number of hydroxyl, amino, and carboxyl reactive groups on the surface of the protein powder, which are partially introduced into the molecular chain segments of the polyurethane resin by reacting with 4,4-diphenylmethane diisocyanate. The urea group formed by the reaction of the amino group and the isocyanate has a structure similar to that of nylon, which increases the leveling performance of the polyurethane resin; the free carboxyl, hydroxyl, and amino groups on the surface of the protein powder have strong hydrophilic properties and can strongly adsorb dye molecules. The adsorbed dye molecules can combine with the amino and urea groups, which greatly improves the dyeing performance of the polyurethane resin;

[0028] (3) In the present invention, the bio-based gel-type protein powder reacts with 4,4-diphenylmethane diisocyanate through its surface active groups, so that the molecular chain presents a cross-linked network structure with the protein powder as the core, the molecules are closely arranged, the intermolecular force is strong, and it has higher mechanical properties and color fixation performance than traditional straight-chain molecules;

[0029] (4) The traditional method of improving dyeing is to introduce dyeing groups (amino, carboxyl, polyetheramine, etc.) into the molecular chain. This only introduces dyeing seats into the polyurethane molecular chain, but there is no dyeing path for the dye to enter. Subsequently, the hydrophilicity of polyethylene glycol and polyethylene glycol-ethylene oxide copolymer is used to increase the adsorption of dyes. However, these hydrophilic groups are embedded in the molecular chain, and only some points increase the adsorption of dyes, which easily causes uneven depth and uneven dyeing, and no dyeing path for the dye to enter is formed. The present invention adds protein powder in the early stage to react, so that the molecular chain has dyeing seats containing dyeing groups, and then fills protein powder in the later stage, and replaces pores with water to form a dyeing path for the dye to enter in a real sense. The design method of combining the dyeing seat and the dyeing path complements each other and brings out the best in each other, and the dyeing, level dyeing and penetrating dyeing are better, which effectively solves the existing problems in suede microfiber dyeing.

[0030] (5) The present invention uses bio-based materials instead of petroleum-based materials to solve the existing problems in ultrafine fiber dyeing. The bio-based gel protein powder comes from natural plants, is food grade, environmentally friendly and safe, and has low cost, which can also effectively reduce material costs;

[0031] (6) After the polyurethane resin provided by the present invention forms a film, the protein powder filled in the molecular gap is replaced by water, presenting a microporous structure similar to that of a sponge, with a large specific surface area, a soft and comfortable surface touch, and a leather-like feel. Compared with similar microfiber products, it is softer, more breathable, more moisture-permeable, and has high resilience.

[0032] (7) The process design of the present invention uses a pre-polymerization and viscosity expansion process in the early stage. In the early stage, polypropylene carbonate polyol and 4,4-diphenylmethane diisocyanate are first reacted (after multiple experiments, it has been verified that the early viscosity expansion is best at 40-60Pa.s / 70°C). In this way, a certain amount of urethane bonds are formed in the soft segment of the molecule, and the cohesive energy of the soft segment molecule is increased. The soft segment can also undergo partial microphase separation through the hydrogen bonding force. During the resin solidification process, the resin film formation speed can be accelerated and the pore wall thickness and strength can be increased, thereby having excellent mechanical properties;

[0033] (8) After the reaction is completed and the chain is terminated, the present invention further adds a portion of bio-based gel-type protein powder as a filler, so that the protein powder is evenly filled in the polyurethane resin; after the ultrafine fibers are impregnated, the polyurethane resin solidifies in water, and the protein powder first swells in water and then dissolves in water and squeezes out, thereby forming a large number of uniform pores similar to a sponge structure in the solidified polyurethane resin film, which can increase the thickness of the ultrafine fibers on the one hand, and provide a channel for the dye to enter the polyurethane resin and the fibers on the other hand, so that the dye can easily enter the fibers and combine with the polyurethane resin, thereby improving the dyeability and saving the amount of dye used. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1The dyeing diagram of the indefinite island toluene reduced suede microfiber in each embodiment and comparative example of the present invention;

[0035] Figure 2 It is a dyeing cross-sectional diagram of the indefinite island toluene weight-reduced suede microfiber in each embodiment and comparative example of the present invention;

[0036] Figure 3 It is the dyeing diagram of Dingdao toluene-reduced suede microfiber in each embodiment and comparative example of the present invention;

[0037] Figure 4 It is a dyeing cross-section diagram of Dingdao toluene-reduced suede microfiber in various embodiments and comparative examples of the present invention. DETAILED DESCRIPTION

[0038] The principles and features of the present invention are described below in conjunction with embodiments. The embodiments are only used to explain the present invention and are not used to limit the scope of the present invention.

[0039] In a specific embodiment, the polypropylene carbonate diol used is PPCD-222 with a number average molecular weight of 2000 g / mol, PPCD-531 with a number average molecular weight of 3000 g / mol, and PPCD-242 with a number average molecular weight of 4000 g / mol from Huizhou Daya Bay Dazhi Fine Chemical Co., Ltd.

[0040] The polytetrahydrofuran diol used was PTMG-2000 with a number average molecular weight of 2000 g / mol from Hangzhou Sanlong New Materials Co., Ltd.

[0041] The polyethylene glycol used was PEG-2000 with a number average molecular weight of 2000 g / mol from Zibo Dexin Chemical Co., Ltd.;

[0042] The bio-based gel protein powder used was YP901E vegetarian soy protein isolate from Shandong Yuwang Industrial (Group) Co., Ltd.;

[0043] The antioxidant used was pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropionate (antioxidant 1010);

[0044] The catalyst used is bismuth neodecanoate, and the bismuth neodecanoate is PUCAT2420 from Hangzhou Jiehui New Materials Co., Ltd.;

[0045] The anti-viscosity reducing agent used was DL-malic acid (2-hydroxysuccinic acid), which was purchased from Jinhu County Lile Biotechnology Industry Co., Ltd.;

[0046] The auxiliary agent used is sodium diisooctyl sulfosuccinate, and the sodium diisooctyl sulfosuccinate is S-11 (40% solid content) produced by Shanghai Rishen Chemical Co., Ltd.

[0047] Example 1

[0048] A method for preparing a hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin specifically comprises the following steps:

[0049] (1) 92.59 g of polypropylene carbonate polyol PPCD-222 and 92.59 g of PPCD-531, 5 g of bio-based gel protein powder YP901E, 0.2 g of antioxidant I-1010, and H 3 PO 4 0.03 g of chlorinated ...

[0050] (2) Raise the temperature to 50°C, then add 18.33 g of MDI, control the reaction temperature to 70-75°C and prepolymerize for 1 hour;

[0051] (3) After the prepolymerization is completed, add 0.96 g of MDI to increase the viscosity until the viscosity reaches 40-60 Pa.s / 70°C;

[0052] (4) Add 200 g DMF and 16 g EG and stir thoroughly;

[0053] (5) Add 64.52 g of MDI and control the temperature at 70-80 °C to react and increase viscosity. During the viscosity increase process, add 0.02 g of catalyst PUCAT2420 and gradually add DMF in three steps (87 g in each step) to dilute the viscosity.

[0054] (6) When the viscosity reaches 100-120 Pas / 25°C, add 60 g of DMF and 0.5 g of methanol to terminate the reaction;

[0055] (7) Add 0.3 g of anti-viscosity reducing agent DL-malic acid, 10 g of auxiliary agent S-11 and 5 g of bio-based gel protein powder YP901E, stir at 60-70° C. for 2 hours, and after completely stirring, cool and pour into a special plastic bottle to finally obtain the hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin with a viscosity of 60-80 Pa.s / 25° C. and a solid content of 30%.

[0056] The types and amounts of raw materials used and the process conditions are shown in Table 1:

[0057] Table 1 Types and amounts of raw materials used in Example 1 and process conditions

[0058]

[0059] Example 2

[0060] A method for preparing a hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin, wherein the specific steps are as described in Example 1.

[0061] The types and amounts of raw materials used and the process conditions are shown in Table 2:

[0062] Table 2 Types and amounts of raw materials used in Example 2 and process conditions

[0063]

[0064] Example 3

[0065] A method for preparing a hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin, wherein the specific steps are as described in Example 1.

[0066] The types and amounts of raw materials used and the process conditions are shown in Table 3:

[0067] Table 3 Types and amounts of raw materials used in Example 3 and process conditions

[0068]

[0069] Example 4

[0070] A method for preparing a hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin, wherein the specific steps are as described in Example 1.

[0071] The types and amounts of raw materials used and the process conditions are shown in Table 4:

[0072] Table 4 Types and amounts of raw materials used in Example 4 and process conditions

[0073]

[0074] Example 5

[0075] A method for preparing a hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin, wherein the specific steps are as described in Example 1.

[0076] The types and amounts of raw materials used and the process conditions are shown in Table 5:

[0077] Table 5 Types and amounts of raw materials used in Example 5 and process conditions

[0078]

[0079] Example 6

[0080] A method for preparing a hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin, wherein the specific steps are as described in Example 1.

[0081] The types and amounts of raw materials used and the process conditions are shown in Table 6:

[0082] Table 6 Types and amounts of raw materials used in Example 6 and process conditions

[0083]

[0084] Comparative Example 1

[0085] A method for preparing a polyurethane resin for toluene-reduced suede-dyed microfiber, wherein the specific steps refer to Example 1.

[0086] The types and amounts of raw materials used and the process conditions are shown in Table 7:

[0087] Table 7 Types and amounts of raw materials used in Comparative Example 1 and process conditions

[0088]

[0089] Comparative Example 2

[0090] A method for preparing a polyurethane resin for toluene-reduced suede-dyed microfiber, specifically comprising the following steps:

[0091] (1) 173.46 g of polytetrahydrofuran diol PTMG-2000, 19.27 g of polyethylene glycol PEG-2000, 0.2 g of antioxidant I-1010, and H 3 PO 4 0.03 g, 373 g DMF, 12.6 g EG and 2.89 g monoethanolamine MEA were put into a three-necked flask and stirred evenly with a mechanical stirrer at high speed;

[0092] (2) Add 86.74 g of MDI and control the reaction temperature to 70-80 °C to increase viscosity. During the viscosity increase process, add 0.02 g of catalyst PUCAT2420 and gradually add DMF in three steps (87 g in each step) to dilute the viscosity.

[0093] (3) When the viscosity reaches 100-120 Pas / 25°C, add 60 g of DMF and 0.5 g of methanol to terminate the reaction;

[0094] (4) Add 0.3 g of anti-viscosity reducing agent DL-malic acid and 10 g of auxiliary agent S-11, stir at 60-70° C. for 2 hours, and after being completely stirred, cool and pour into a special plastic bottle to finally obtain the toluene-reduced suede-dyed microfiber polyurethane resin with a viscosity of 60-80 Pa.s / 25° C. and a solid content of 30%.

[0095] The types and amounts of raw materials used and the process conditions are shown in Table 8:

[0096] Table 8 Types and amounts of raw materials used in Comparative Example 2 and process conditions

[0097]

[0098] Comparative Example 3

[0099] A method for preparing a polyurethane resin for toluene-reduced suede-dyed microfiber, with specific steps referring to Comparative Example 2.

[0100] The types and amounts of raw materials used and the process conditions are shown in Table 9:

[0101] Table 9 Types and amounts of raw materials used in Comparative Example 3 and process conditions

[0102]

[0103] Performance Test:

[0104] Performance test ratio and reduction process: Weigh 100 grams of the polyurethane resin obtained in Examples 1-6 and Comparative Examples 1-3 respectively with an electronic balance, add 50 grams of DMF, stir evenly with a high-speed disperser, and then centrifuge for 10 minutes (1500 rpm). Uniformly extrude and impregnate the polyurethane slurry after centrifugation into the ultrafine fibers, and the sizing amount is 40±1% of the fiber weight. Then put it into a DMF aqueous solution coagulation tank for coagulation. The concentration of the DMF aqueous solution in the coagulation tank is 25-30%, and the coagulation temperature is 30-35°C. After complete coagulation, wash off the residual DMF with clean water, put it into a heating box at 100°C for drying, and then reduce the fiber in 100°C toluene to obtain an ultrafine bass.

[0105] Microfiber dyeing process: Add the prepared dye water into the dyeing drum, put in the microfiber bass that has been reduced, run the drum at room temperature for 10 minutes, use the program temperature rise method, heat up to 50℃ at a rate of 1℃ / min, keep constant temperature for 10 minutes, then heat up to 60℃ at a rate of 1℃ / min, keep constant temperature for 10 minutes, then heat up to 70℃ at a rate of 1℃ / min, keep constant temperature for 10 minutes, then heat up to 80℃ at a rate of 1℃ / min, keep constant temperature for 10 minutes, then add formic acid, keep constant temperature at 80℃ for 30 minutes. After dyeing is completed and cooled naturally, release the dye solution, add clean water to the drum, wash for 10-20 minutes, take out the dyed microfiber bass, and put it into the heating box at 100℃ for drying.

[0106] Note: The dye water includes dye, water and formic acid (fixing agent). The dye is BLNIL8160 (red) acid dye of Zhejiang Shenlan New Materials Technology Co., Ltd. The amount of dye is 2% of the weight of the microfiber, the amount of water is 20 times the weight of the microfiber, and the amount of formic acid is 1.8% of the weight of the microfiber.

[0107] The performance test results of the indefinite island toluene reduced suede microfiber are shown in Table 10.

[0108] Table 10 Performance test results of indeterminate island toluene reduction suede microfiber

[0109]

[0110]

[0111] By comparing the polyurethane resins of Examples 1-6 with those of Comparative Examples 1-3 in the test of indefinite island toluene reduction suede microfiber, and combining Figure 1 and Figure 2 It can be seen that:

[0112] (1) It can be seen from Examples 1-6 that the color fastness, dyeability, levelness and dye penetration of the indefinite island suede microfiber prepared by the polyurethane resin of the present invention are relatively good. This is mainly because the bio-based gel-type protein powder with active groups is grafted into the molecular chain through chemical bonds. The bio-based gel-type protein powder has its own dyeing groups to provide the dyeing seat required for dyeing, and then the bio-based gel-type protein powder is added to provide the dye to enter the required dyeing channel after washing and displacement. The two are combined with each other and have complementary properties, making the polyurethane resin have excellent dyeing properties. The indefinite island suede microfiber of the polyurethane resin without adding bio-based gel-type protein powder has poor dyeability, levelness and dye penetration. This is mainly because the dyeing seat and dyeing channel required for dyeing do not exist in the molecule, which can be seen from Comparative Example 1.

[0113] (2) It can be seen from Comparative Examples 2 and 3 that the resin, after introducing hydrophilic polyethylene glycol, amino group and carboxyl group into the molecule, has a slightly worse dyeability than that of Examples 1-6, but better dyeability than that of Comparative Example 1. This is mainly because both polyethylene glycol and carboxyl group can improve the hydrophilicity of the resin and enhance the adsorption of dyes, and the amino group can combine with the dye molecules. Therefore, the dyeability is better than that of Comparative Example 1, but the levelness and dye penetration are relatively poor. This is because the resin itself does not have a dye path for the dye to enter, but only the adsorption of the dye in some parts is enhanced, which will inevitably lead to uneven coloring and poor dye penetration. Because there is no dye path, the dyeability is also slightly worse than that of Examples 1-6.

[0114] (3) It can be seen from Examples 1-6 and Comparative Examples 1-3 that the suede microfiber prepared from the polyurethane resin of the present invention has excellent mechanical properties, and the tear strength is on average 1.44 kg / 2.5 mm thick. This is mainly because polypropylene carbonate contains a polycarbonate structure and has strong mechanical properties.

[0115] (4) It can be seen from Examples 1-6 and Comparative Examples 1-3 that the color fastness of the suede microfiber prepared by the polyurethane resin of the present invention is greatly improved, with an average improvement of 2 levels. There are two main reasons for this. First, the molecular structure of the present invention presents a network structure centered on bio-based gel-type protein powder, which has higher mechanical properties than the traditional straight-chain structure. On the other hand, the polycarbonate structure in the molecular chain further enhances the mechanical and color-fixing properties.

[0116] (5) It can be seen from Examples 1-6 and Comparative Examples 1-3 that the hydrolysis resistance of the suede microfiber prepared by the polyurethane resin of the present invention is greatly improved. The tear strength is slightly reduced after immersion in alkali solution and remains basically unchanged. However, the tear strength of the traditional polyether material is reduced by about 20% after immersion in alkali solution. This is mainly because the polypropylene carbonate diol used in the present invention has both polycarbonate and polyether structures and has excellent hydrolysis resistance. The traditional method is to increase the polyethylene glycol introduced into the molecular chain by dyeing, which has strong hydrophilicity and poor hydrolysis resistance, which is also the reason for the reduction in hydrolysis resistance.

[0117] (6) It can be seen from Examples 1-6 and Comparative Examples 1-3 that the suede microfiber prepared by the polyurethane resin of the present invention has a more excellent hand feel, which is mainly because part of the protein powder is grafted into the molecular chain, and the surface of the protein powder has a delicate, soft and comfortable touch; part of the protein powder monomer is filled in the polyurethane molecule, and after coagulation and displacement, a sponge-like microporous structure is formed on the polyurethane carrier, with a large specific surface area and a delicate and soft hand feel. At the same time, due to the sponge-like microporous structure, the suede microfiber prepared by the polyurethane resin of the present invention has a more excellent air permeability, which is more than 30% higher than the air permeability of the microfiber prepared by the traditional method, while Comparative Examples 1-3 have no sponge pore structure, and the hand feel is relatively board and hard, and the air permeability is poor.

[0118] The performance test results of Dingdao toluene-reduced suede microfiber are shown in Table 11.

[0119] Table 11 Performance test results of Dingdao toluene-reduced suede microfiber

[0120]

[0121]

[0122] By comparing the polyurethane resins of Examples 1-6 with those of Comparative Examples 1-3 in the Dingdao toluene reduction suede microfiber test, and combining Figure 3 and Figure 4It can be seen that the test results of various properties are basically consistent with those of the indeterminate-island suede microfiber. This is mainly because whether it is the fixed-island or indeterminate-island suede microfiber, the only difference is the spinning process, and the fiber coloring mechanism is the same. The microfiber resin prepared by the present invention has both dyeing seat and dyeing channel, and has a wide applicability, which solves the problem of suede microfiber dyeing difficulty in the industry at one stroke.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin, characterized in that: The invention comprises the following components by weight: 17.72-18.52 parts of polypropylene carbonate polyol; 1-2 parts of bio-based gel protein powder; 0.02 parts of antioxidant; 0.003 parts of phosphoric acid H3PO4; 0.002 parts of catalyst; 1.54-1.75 parts of ethylene glycol EG; 8.09-8.39 parts of 4,4-diphenylmethane diisocyanate MDI; 0.03 parts of anti-viscosity reducing agent; 0.05 parts of methanol CH3OH; 69-70 parts of N,N-dimethylformamide DMF; 1 part of auxiliary agent; The preparation method of the hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin comprises the following steps: firstly, polypropylene carbonate polyol, the first part of bio-based gel protein powder, antioxidant, H3PO4 and the first part of DMF are fully stirred, then the first part of MDI is added, and the reaction temperature is controlled to be 70-75°C for constant temperature prepolymerization for 1-2 hours; After the prepolymerization is completed, the second part of MDI is added to increase the viscosity. When the viscosity reaches 40-60 Pa·s / 70°C, the second part of DMF and EG are added. After being fully stirred, the remaining MDI is added again, and the temperature is controlled at 70-80°C to react and increase the viscosity. During the viscosity increase process, a catalyst is added, and the third part of DMF is gradually added to dilute the viscosity until the viscosity reaches 100-120 Pa·s / 25°C. The remaining DMF and methanol are added for end-capping, the reaction is terminated, and then an anti-viscosity reducing agent, an auxiliary agent and the remaining bio-based gel-type protein powder are added. After being completely stirred, the mixture is cooled and packaged to finally obtain the hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin.

2. The hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin according to claim 1, characterized in that: The polypropylene carbonate polyol includes polypropylene carbonate diol.

3. The hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin according to claim 1, characterized in that: The antioxidant includes pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropionate, the catalyst includes bismuth neodecanoate, the anti-viscosity reduction agent includes DL-malic acid, and the auxiliary agent includes sodium diisooctyl sulfosuccinate.

4. A method for preparing a hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin as claimed in any one of claims 1 to 3, characterized in that: The method comprises the following steps: firstly, fully stirring polypropylene carbonate polyol, the first part of bio-based gel protein powder, an antioxidant, H3PO4 and the first part of DMF, then adding the first part of MDI, controlling the reaction temperature to be 70-75°C and prepolymerizing at a constant temperature for 1-2 hours; After the prepolymerization is completed, the second part of MDI is added to increase the viscosity. When the viscosity reaches 40-60 Pa·s / 70°C, the second part of DMF and EG are added. After being fully stirred, the remaining MDI is added again, and the temperature is controlled at 70-80°C to react and increase the viscosity. During the viscosity increase process, a catalyst is added, and the third part of DMF is gradually added to dilute the viscosity until the viscosity reaches 100-120 Pa·s / 25°C. The remaining DMF and methanol are added for end-capping, the reaction is terminated, and then an anti-viscosity reducing agent, an auxiliary agent and the remaining bio-based gel-type protein powder are added. After being completely stirred, the mixture is cooled and packaged to finally obtain the hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin.

5. The method for preparing the hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin according to claim 4, characterized in that: After adding the anti-viscosity reducing agent, the auxiliary agent and the bio-based gel protein powder, the stirring temperature is 60-70° C. and the stirring time is 1-2 hours.

6. The method for preparing the hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin according to claim 4, characterized in that: The bio-based gel protein powder is added in two parts at a weight ratio of 1:1, the DMF is added in four parts at a weight ratio of (16.4-17.3):(20-20.9):26.1:6, and the MDI is added in three parts at a weight ratio of (18.8-19.2):1:(66.9-105.2).

7. The method for preparing the hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin according to claim 6, characterized in that: When adding the third portion of DMF, add it in three steps, and the mass of DMF added in each step is equal.

8. Use of the hydrolysis-resistant toluene-reduced suede-dyed microfiber polyurethane resin as claimed in any one of claims 1 to 3 in the field of toluene-reduced suede microfiber.

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