A high-transparency polyurethane resin stock solution and its application

Abstract

The invention discloses a high-transmittance polyurethane resin stock solution and application thereof. Component A comprises: 75% to 90% of a polyester polyol A1 having a number average molecular weight of 1400 to 1600, 3% to 10% of a nucleating agent A2, 3% to 10% of a polyester polyol A3 having a number average molecular weight of 1800 to 2200, 1% to 10% of a difunctional chain extender, and 0.3% to 3% of a trihydroxy crosslinking agent; component B comprises: 50% to 70% of an isocyanate B1 and 30% to 50% of a polyester polyol B2 having a molecular weight of 1800 to 2200; the molar ratio of the total active hydroxyl groups in component A to the total isocyanate groups in component B is 1:(0.98 to 1.02); the nucleating agent A2 is a hydroxyl-terminated polymer obtained by esterifying a mixture of (1,3:2,4)-dibenzylidene sorbitol and ethylene glycol with adipic acid, and the number average molecular weight is 800 to 1000; the product has good appearance and transparency.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane production, and particularly relates to a high-transmittance polyurethane resin stock solution and application thereof. Background Art

[0002] Polyurethane, or polyurethane, is a polymer material with properties intermediate between those of rubber and plastic. Its molecular structure consists of soft and hard segments. The soft segments are composed of long-chain polyester polyols, polyether polyols, and other polyols with specialized structures. The hard segments are derived from the reaction of isocyanates with active hydrogen-containing substances such as small-molecule polyols or small-molecule polyamines. Most polyurethanes are semi-crystalline polymers, with both the soft and hard segments capable of crystallization. However, when the degree of crystallinity is high and the crystal size is large, the product's transparency decreases, or even becomes opaque.

[0003] Currently, transparent polyurethane products are generally produced using thermoplastic polyurethane (TPU) through extrusion and injection molding processes under high temperature and high pressure. However, this method has high equipment investment costs, low production efficiency, and insufficient transparency. Transparent polyurethane products are also produced using a two-component polyurethane stock solution. This is mixed and poured directly into a mold using a low-pressure foaming machine. With the help of a catalyst, the product is molded and ejected after 3-5 minutes. This method is simple, low-cost, and highly efficient; however, it suffers from poor transparency when producing products with a hardness of 70A-90A.

[0004] Therefore, when using a two-component polyurethane stock solution to prepare transparent polyurethane products, it is necessary to reduce the crystal size and improve transparency. There are two existing methods to improve transparency: one is to optimize the polyurethane formula, and the other is to add a clarifier.

[0005] Currently, most researchers in the polyurethane field are using methods such as introducing special molecular structures or introducing side groups and branches to improve the transparency of materials. For example, patent document CN115746245A discloses a method for preparing a transparent polyurethane composite material, comprising components A and B. Component A includes polyester polyol a, a chain extender, a crosslinker, a foam stabilizer, and a catalyst, and component B includes polyester polyol b and an isocyanate. Polyester polyol b is prepared by polymerization of linear and branched small molecule alcohols with aliphatic polyacids. The side chain groups in polyester polyol b disrupt the orderly arrangement of the macromolecular polyurethane structure, making it disorganized and improving the transparency of the polyurethane product. Patent document CN115926099A discloses a thermoplastic polyurethane and its preparation method, comprising the following raw materials: 30-80 parts by mass of a polyol; 0.01-10 parts by mass of a modified adamantane alcohol; 20-50 parts by mass of a diisocyanate; and 3-17 parts by mass of a diol chain extender. By modifying the unique molecular structure of adamantane alcohol, a thermoplastic polyurethane with excellent transparency and mold release properties has been achieved. However, this approach may increase material costs or reduce other physical and mechanical properties.

[0006] Most researchers in the plastics field, however, add clarifiers or nucleating agents and use a screw extruder under high temperature and strong shear to physically mix them with the base material (such as polypropylene) to achieve uniform dispersion. After injection molding and cooling, highly transparent products are obtained. For example, (1,3:2,4)-dibenzylidene sorbitol compounds are used as nucleating agents. Sorbitol-based transparent nucleating agents are currently the most widely used organic polyolefin transparent nucleating agents internationally. These products are divided into three generations based on the substituent groups: the first generation is DBS, chemically known as 1,3:2,4-dibenzylidene sorbitol; the second generation is MDBS, chemically known as 1,3:2,4-di(p-methyldibenzylidene) sorbitol; and the third generation is DMDBS, chemically known as 1,3:2,4-di(3,4-dimethyldibenzylidene) sorbitol. Due to the presence of two free hydroxyl groups within the (1,3:2,4)-dibenzylidene sorbitol molecule, when polypropylene resin is melted, hydrogen bonding between the free hydroxyl groups forms a three-dimensional nanofiber network with a supramolecular structure, leading to gelation. The surface of the nanofiber forms nucleation centers, promoting heterogeneous nucleation and crystallization. This control of spherulite growth increases the number of nuclei, resulting in more complete crystallization and more uniform stress distribution, thereby improving the mechanical properties of polypropylene. Patent documents JP2011207991A, CN113999456A, CN113121911A, CN105647016A, and CN105949616A, respectively, utilize (1,3:2,4)-dibenzylidene sorbitol-based clarifiers or nucleating agents to increase the crystallinity of polypropylene, thereby improving the tensile yield strength of the modified polypropylene material and enabling the formation of polypropylene resin compositions with excellent transparency. CN111978623A and CN110204816A use (1,3:2,4)-dibenzylidene sorbitol-based clarifiers or nucleators to improve the transparency of linear low-density polyethylene (LLDPE) cast wrap film. CN112724652A uses a sorbitol-based nucleator to prepare highly transparent thermoplastic polyurethane elastomers for electronic products. CN113174079A uses a sorbitol-based nucleator to prepare polyurethane-based scratch-resistant optical reflective film.

[0007] However, there are no reports on the addition of nucleating agents to two-component polyurethane stock solutions. The operating temperature of a two-component polyurethane stock solution is between 40-60°C. Directly adding a nucleating agent, due to its high melting point, typically exceeding 200°C, results in poor dispersion in the two-component polyurethane stock solution and ineffective nucleation. Therefore, in this field, traditional nucleating agents are chemically modified to improve their compatibility with the two-component polyurethane, imparting excellent nucleating properties and enabling in-situ nucleation on the polyurethane molecular chain. Adding this agent to a two-component polyurethane product can result in highly transparent products. Summary of the Invention

[0008] The purpose of the present invention is to provide a preparation method and application of a high-transparency polyurethane resin stock solution to solve the problem of insufficient transparency of polyurethane sole products in the prior art.

[0009] In order to achieve the above objectives, the technical solutions of the present invention are as follows.

[0010] The high-transmittance polyurethane resin stock solution of the present invention comprises component A and component B, and is characterized in that:

[0011] The component A comprises the following raw materials in mass fractions: 75% to 90% of polyester polyol A1 with a number average molecular weight of 1400 to 1600, 3% to 10% of nucleating agent A2, 3% to 10% of polyester polyol A3 with a number average molecular weight of 1800 to 2200, 1% to 10% of difunctional chain extender and 0.3% to 3% of trihydroxy crosslinking agent;

[0012] The B component comprises the following raw materials by mass fraction: 50% to 70% of isocyanate B1 and 30% to 50% of polyester polyol B2 with a molecular weight of 1800 to 2200;

[0013] The ratio of the molar number of the total active hydroxyl groups of the A component to the molar number of the total isocyanate groups of the B component is 1:(0.98-1.02);

[0014] The nucleating agent A2 is a hydroxyl-terminated polymer obtained by esterifying a mixture of (1,3:2,4)-dibenzylidene sorbitol (CAS No. 19046-64-1) and ethylene glycol with adipic acid, and has a number average molecular weight of 800 to 1000. Preferably, the nucleating agent A2 is a hydroxyl-terminated polymer obtained by esterifying a mixture of 32% to 65% by mass of (1,3:2,4)-dibenzylidene sorbitol, 5% to 35% by mass of ethylene glycol, and 30% to 50% by mass of adipic acid, and has a number average molecular weight of 850 to 900.

[0015] The preparation process of the nucleating agent A2 is as follows: start stirring and add ethylene glycol, (1,3:2,4)-dibenzylidene sorbitol and adipic acid to the reactor in sequence; after the addition is completed, heat it to 130-150° C. and stir to dehydrate for 2-5 hours, then heat it to 230-245° C. and stir to react for 4-7 hours; add an esterification catalyst, evacuate to a vacuum degree of -0.098 to -0.090 MPa, and react for 3-5 hours; take samples for testing, and obtain a nucleating agent A2 with an acid value of 0.2-0.8 mgKOH / g and a hydroxyl value of 124.6-132 mgKOH / g.

[0016] Preferably, in the high-permeability polyurethane resin stock solution described in the present invention, the component A is composed of the following components in mass fraction: 75% to 85% polyester polyol A1, 4% to 9% nucleating agent A2, 3% to 8% polyester polyol A3, 1% to 9% difunctional chain extender and 0.3% to 2.5% trihydroxy crosslinker; the component B is composed of the following components in mass fraction: 50% to 68% isocyanate B1, 32% to 50% polyester polyol B2 and 0.001% to 0.005% of side reaction inhibitor.

[0017] Preferably, the polyester polyol A1 is a polyester polyol with a number average molecular weight of 1450 to 1550 formed by esterification reaction of a combination of any two or three of ethylene glycol, 1,4-butanediol, and diethylene glycol with adipic acid; more preferably, the polyester polyol A1 is a polyester polyol with a number average molecular weight of 1450 to 1550 formed by esterification reaction of 3% to 19% of ethylene glycol, 3% to 18% of 1,4-butanediol, 2% to 25% of diethylene glycol and 60% to 64% of adipic acid.

[0018] Preferably, the polyester polyol A3 is a polyester polyol having a number average molecular weight of 1900 to 2100, which is prepared by esterification of adipic acid with a combination of any two or three of ethylene glycol, 1,4-butanediol, and dipropylene glycol.

[0019] Preferably, the isocyanate B1 is any one of diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, toluene diisocyanate or naphthalene diisocyanate, or a combination of at least two thereof.

[0020] Preferably, the polyester polyol B2 is prepared by esterification and polycondensation of the following components by mass fraction: 3% to 19% ethylene glycol, 3% to 18% 1,4-butanediol, 2% to 25% diethylene glycol and 60% to 64% adipic acid.

[0021] Preferably, the difunctional chain extender is at least one of ethylene glycol, 1,4-butanediol, 1,3-propylene glycol or 1,6-hexanediol; and the trihydroxy crosslinker is at least one of glycerol, trimethylolpropane or 1,2,6-hexanetriol.

[0022] Preferably, the raw materials for preparing component A also include a catalyst with a mass fraction of 0.7% to 3%, and the catalyst is a mixture of triethylenediamine and ethylene glycol in a mass ratio of 1:(2 to 3); further preferably, the mass ratio of triethylenediamine to ethylene glycol solution is 1:(2 to 2.3).

[0023] Preferably, the raw materials for preparing component B further include a side reaction inhibitor accounting for 0.001% to 0.008% of the total mass of component B; the side reaction inhibitor is phosphoric acid and / or benzoyl chloride.

[0024] The method for preparing a high-permeability polyurethane resin stock solution of the present invention is characterized by comprising the following steps: (1) mixing and stirring the raw materials of the component A at 50-60° C. for 1.0-2.5 hours until uniform, cooling to 40-45° C., and further mixing and stirring for 1.0-1.5 hours to adjust the hydroxyl value to within an acceptable range, thereby obtaining the component A;

[0025] (2) The raw materials for preparing component B are stirred and mixed, and reacted at a temperature of 60-70° C. for 2-3 hours to adjust the NCO content of component B to be within the qualified range to obtain component B.

[0026] The high-permeability polyurethane resin stock solution described herein is used to prepare polyurethane resin products, such as polyurethane shoe outsoles or polyurethane shoe upper patches, comprising the following steps: thoroughly mixing component A and component B, injecting them into a mold for reaction molding, demolding, and aging to obtain the polyurethane resin product. Preferably, before mixing, the temperatures of component A and component B are maintained at 40-45°C, respectively; the reaction temperature in the mold is 45-55°C, and the reaction time is 3-5 minutes; the aging temperature is 55-70°C, and the aging time is 6-24 hours.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention uses carboxyl groups in adipic acid and hydroxyl groups in (1,3:2,4)-dibenzylidene sorbitol to carry out an esterification reaction. Simultaneously, an esterification reaction of adipic acid and ethylene glycol is also carried out. The ester groups formed by the two can also undergo an ester exchange reaction to carry out molecular rearrangement. At the same time, the main molecular chain of the (1,3:2,4)-dibenzylidene sorbitol in the nucleating agent contains hydroxyl groups, which can react with the isocyanate groups in the component B of the polyurethane stock solution, so that the main molecular structure of the (1,3:2,4)-dibenzylidene sorbitol is embedded in the polyurethane molecular chain to carry out in-situ nucleation. The prepared nucleating agent has excellent compatibility and dispersibility with the component A of the polyurethane stock solution at 40-60°C, thereby solving the problem of poor dispersibility of traditional nucleating agents in the polyurethane stock solution due to high melting point and poor compatibility, thereby achieving the effect of improving transparency.

[0029] The method of the invention has strong operability, is economical and affordable, and has excellent product performance. The polyurethane resin prepared by adopting the high-transparency polyurethane resin stock solution of the invention has high transparency. DETAILED DESCRIPTION

[0030] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the invention.In addition, should be understood that after reading content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope of the application's appended claims limitation.

[0031] Example 1

[0032] Example 1 is the preparation process of nucleating agent A2: turn on the stirring, and add 50g of ethylene glycol, 210g of (1,3:2,4)-dibenzylidene sorbitol and 146g of adipic acid in sequence to a reactor equipped with nitrogen, condensation reflux and vacuum device; after the addition is completed, the temperature is raised to 140°C and stirred for dehydration reaction for 3h, and then the temperature is raised to 240°C and stirred for reaction for 5h; 0.01g of tetraisopropyl titanate is added as a catalyst, vacuum is applied, and the reaction is carried out at a vacuum degree of -0.098Mpa for 4h; sampling and testing obtain a nucleating agent A2 with an acid value of 0.5mgKOH / g and a hydroxyl value of 124.6mgKOH / g.

[0033] The acid value of nucleating agent A2 was measured according to standard HG / T 2708-1995, and the hydroxyl value of nucleating agent A2 was measured according to standard HG / T 2709-1995. The number average molecular weight was calculated as 112200 / hydroxyl value, and the number average molecular weight of nucleating agent A2 was 900.

[0034] Example 2

[0035] Example 2 is the preparation process of nucleating agent A2: turn on the stirring, and add 40g of ethylene glycol, 268g of (1,3:2,4)-dibenzylidene sorbitol and 146g of adipic acid in sequence to a reactor equipped with nitrogen, condensation reflux and vacuum device; after the feeding is completed, the temperature is raised to 140°C and stirred for dehydration reaction for 3h, and then the temperature is raised to 240°C and stirred for reaction for 5h; 0.015g of tetraisopropyl titanate is added as a catalyst, vacuum is applied, and the reaction is carried out at a vacuum degree of -0.098Mpa for 4.5h; sampling and testing obtain a nucleating agent A2 with an acid value of 0.3mgKOH / g and a hydroxyl value of 124.6mgKOH / g.

[0036] The acid value of nucleating agent A2 was measured according to standard HG / T 2708-1995, and the hydroxyl value of nucleating agent A2 was measured according to standard HG / T 2709-1995. The number average molecular weight = 112200 / hydroxyl value, and the number average molecular weight of nucleating agent A2 was calculated to be 850.

[0037] Example 3

[0038] The transparent polyurethane resin stock solution of Example 3 is composed of component A and component B.

[0039] The component A comprises: 81 g of polyester polyol A1 (a polyester polyol with a number average molecular weight of 1500 obtained by esterification polycondensation of 9.8% ethylene glycol, 12.7% 1,4-butanediol, 16.7% diethylene glycol and 60.8% adipic acid), 3.5 g of nucleating agent A2 (prepared in Example 1), 5 g of polyester polyol A3 (a polyester polyol with a number average molecular weight of 2000 obtained by esterification of 9.4% ethylene glycol, 18.1% 1,4-butanediol, 12.4% dipropylene glycol and 60.1% adipic acid), 8 g of ethylene glycol, 1.5 g of glycerol and 1 g of catalyst (a mixture of triethylenediamine and ethylene glycol in a mass ratio of 1:2); the above raw materials are mixed and stirred at 55 ° C for 2 h, cooled to below 45 ° C, the hydroxyl value is adjusted to within the qualified range, and sealed for storage to obtain component A.

[0040] The B component is as follows: 63g of isocyanate B1 (4,4-diphenylmethane diisocyanate) is added to a reactor, the temperature is maintained at 50°C, 0.003g of a side reaction inhibitor (phosphoric acid) is added, and the mixture is stirred for 15 minutes; then 37g of polyester polyol B2 (a polyester polyol with a number average molecular weight of 2000 prepared by esterification and polycondensation of 16.2% ethylene glycol, 11.7% 1,4-butanediol, 9.1% diethylene glycol and 63% adipic acid) is added, the process temperature is controlled at 60-70°C, the reaction is carried out for 3 hours, sampling is carried out for testing, the NCO content is adjusted to within the qualified range, the temperature is lowered to 45°C, the material is discharged, and the material is sealed and stored to obtain the B component.

[0041] When the product is manufactured, the mass ratio of component A to component B is 100:96, and the ratio of the molar number of total active hydroxyl groups in component A to the molar number of total isocyanate groups in component B is 1:1.

[0042] Example 4

[0043] The transparent polyurethane resin stock solution of Example 4 is composed of component A and component B.

[0044] The component A is: 75g of polyester polyol A1 (a polyester polyol with a number average molecular weight of 1500 prepared by esterification reaction of 9.8% ethylene glycol, 12.7% 1,4-butanediol, 16.7% diethylene glycol and 60.8% adipic acid), 7.5g of nucleating agent A2 (prepared in Example 1), 7g of polyester polyol A3 (a polyester polyol with a number average molecular weight of 2000 prepared by esterification reaction of 9.2% ethylene glycol, 18.1% 1,4-butanediol, 12.5% ​​dipropylene glycol and 60.2% adipic acid), 8g of 1,4-butanediol, 1.5g of trimethylolpropane and 1g of catalyst (a mixture of triethylenediamine and ethylene glycol in a mass ratio of 1:2); after mixing and stirring the above raw materials at 55°C for 2h, cooling to below 45°C, adjusting the hydroxyl value to within the qualified range, and sealing and storing to obtain component A.

[0045] The B component is as follows: 63g of isocyanate B1 (4,4-diphenylmethane diisocyanate) and ester are added to a reactor, the temperature is maintained at 50°C, 0.003g of a side reaction inhibitor (phosphoric acid) is added, and the mixture is stirred for 15 minutes. Then, 37g of polyester polyol B2 (a polyester polyol with a number average molecular weight of 2000 prepared by esterification and polycondensation of 16.2% ethylene glycol, 11.7% 1,4-butanediol, 9.1% diethylene glycol and 63% adipic acid) is added, the process temperature is controlled at 60-70°C, the reaction is carried out for 3 hours, sampling and testing are performed, the NCO content is adjusted to within the qualified range, the temperature is lowered to 45°C, the material is discharged, and the material is sealed and stored to obtain the B component.

[0046] When the product is manufactured, the mass ratio of component A to component B is 100:77, and the ratio of the molar number of total active hydroxyl groups in component A to the molar number of total isocyanate groups in component B is 1:1.

[0047] Example 5

[0048] The transparent polyurethane resin stock solution of Example 5 is composed of component A and component B.

[0049] The component A comprises: 81.5 g of polyester polyol A1 (a polyester polyol with a number average molecular weight of 1500 prepared by esterification polycondensation of 16.5% ethylene glycol, 6.3% 1,4-butanediol, 13.4% diethylene glycol and 63.8% adipic acid), 7.5 g of nucleating agent A2 (prepared in Example 1), 7 g of polyester polyol A3 (prepared by 17.7% ethylene glycol, 8.4% 1,4-butanediol, 12. 9% dipropylene glycol and 61.0% adipic acid (a polyester polyol with a number average molecular weight of 2000, prepared by esterification), 1.5g 1,4-butanediol, 1.5g trimethylolpropane and 1g catalyst (a mixture of triethylenediamine and ethylene glycol in a mass ratio of 1:2); the above raw materials were mixed and stirred at 55°C for 2h, cooled to below 45°C, the hydroxyl value was adjusted to within the qualified range, and sealed for storage to obtain component A.

[0050] The B component is as follows: 63g of isocyanate B1 (4,4-diphenylmethane diisocyanate) and ester are added to a reactor, the temperature is maintained at 50°C, 0.003g of a side reaction inhibitor (phosphoric acid) is added, and the mixture is stirred for 15 minutes. Then, 37g of polyester polyol B2 (a polyester polyol with a number average molecular weight of 2000 prepared by esterification of 14.2% ethylene glycol, 5% diethylene glycol, 18% 1,4-butanediol and 62.8% adipic acid) is added, the process temperature is controlled at 60-70°C for reaction for 3 hours, sampling is performed for detection, the NCO content is adjusted to within the qualified range, the temperature is lowered to 45°C for discharge, and the mixture is sealed and stored to obtain the B component.

[0051] When the product is manufactured, the mass ratio of component A to component B is 100:48, and the ratio of the molar number of total active hydroxyl groups in component A to the molar number of total isocyanate groups in component B is 1:1.

[0052] Example 6

[0053] The transparent polyurethane resin stock solution of Example 6 is composed of component A and component B.

[0054] The component A is: 79g of polyester polyol A1 (a polyester polyol with a number average molecular weight of 1500 prepared by esterification reaction of 14.3% ethylene glycol, 16.1% 1,4-butanediol, 6.6% diethylene glycol and 63% adipic acid), 7.5g of nucleating agent A2 (prepared in Example 2), 7g of polyester polyol A3 (a polyester polyol with a number average molecular weight of 2000 prepared by esterification reaction of 23.8% ethylene glycol, 13% dipropylene glycol and 63.2% adipic acid), 4g of 1,4-butanediol, 1.5g of 1,2,6-hexanetriol and 1g of catalyst (a mixture of triethylenediamine and ethylene glycol in a mass ratio of 1:2); after mixing and stirring the above raw materials at 55°C for 2h, cooling to below 45°C, adjusting the hydroxyl value to within the qualified range, and sealing and storing to obtain component A.

[0055] The B component is as follows: 63g of isocyanate B1 (4,4-diphenylmethane diisocyanate) and ester are added to a reactor, the temperature is maintained at 50°C, 0.003g of a side reaction inhibitor (phosphoric acid) is added, and the mixture is stirred for 15 minutes. Then, 37g of polyester polyol B2 (a polyester polyol with a number average molecular weight of 2000 prepared by esterification and polycondensation of 9.7% ethylene glycol, 20.2% 1,4-butanediol, 8.9% diethylene glycol and 61.2% adipic acid) is added, the process temperature is controlled at 60-70°C, the reaction is carried out for 3 hours, sampling and testing are performed, the NCO content is adjusted to within the qualified range, the temperature is lowered to 45°C, the material is discharged, and the material is sealed and stored to obtain the B component.

[0056] When the product is manufactured, the mass ratio of component A to component B is 100:59, and the ratio of the molar number of total active hydroxyl groups in component A to the molar number of total isocyanate groups in component B is 1:1.

[0057] Example 7

[0058] The transparent polyurethane resin stock solution of Example 7 is composed of component A and component B.

[0059] The component A is: 79g of polyester polyol A1 (a polyester polyol with a number average molecular weight of 1500 prepared by esterification reaction of 8.8% ethylene glycol, 14% 1,4-butanediol, 16.7% diethylene glycol and 60.5% adipic acid, 7.5g of nucleating agent A2 (prepared in Example 2), 3g of polyester polyol A3 (a polyester polyol with a number average molecular weight of 2000 prepared by esterification reaction of 9.2% ethylene glycol, 18.1% 1,4-butanediol, 12.5% ​​dipropylene glycol and 60.2% adipic acid), 8g of 1,4-butanediol, 1.5g of trimethylolpropane and 1g of catalyst (a mixture of triethylenediamine and ethylene glycol in a mass ratio of 1:2); after mixing and stirring the above raw materials at 55°C for 2h, cooling to below 45°C, adjusting the hydroxyl value to within the qualified range, and sealing and storing to obtain component A.

[0060] The B component is as follows: 68g of isocyanate B1 (4,4-diphenylmethane diisocyanate) and ester are added to a reactor, the temperature is maintained at 50°C, 0.003g of a side reaction inhibitor (phosphoric acid) is added, and the mixture is stirred for 15 minutes. Then, 32g of polyester polyol B2 (a polyester polyol with a number average molecular weight of 2000 prepared by esterification and polycondensation of 17.2% ethylene glycol, 12.7% 1,4-butanediol, 9.1% diethylene glycol and 61% adipic acid) is added, the process temperature is controlled at 60-70°C, the reaction is carried out for 3 hours, sampling is carried out for detection, the NCO content is adjusted to within the qualified range, the temperature is lowered to 45°C, the material is discharged, and the material is sealed and stored to obtain the B component.

[0061] When the product is manufactured, the mass ratio of component A to component B is 100:70, and the ratio of the molar number of total active hydroxyl groups in component A to the molar number of total isocyanate groups in component B is 1:1.

[0062] Comparative Example 1

[0063] Comparative Example 1 is a comparative example of Example 3, except that the polyester polyol A2 is not added to the component A of this comparative example, and the transparent polyurethane resin stock solution consists of the components A and B.

[0064] The component A comprises: 84.5 g of polyester polyol A1, 5 g of polyester polyol A3, 8 g of ethylene glycol, 1.5 g of propylene glycol, and 1 g of a catalyst (a mixture of triethylenediamine and ethylene glycol in a mass ratio of 1:2); the above raw materials are mixed and stirred at 55° C. for 2 h, cooled to below 45° C., the hydroxyl value is adjusted to within the qualified range, and the mixture is sealed and stored to obtain component A.

[0065] The B component is as follows: 63g of isocyanate B1 (4,4-diphenylmethane diisocyanate) is added to a reactor, the temperature is maintained at 50°C, 0.003g of a side reaction inhibitor (phosphoric acid) is added, and the mixture is stirred for 15 minutes; 37g of polyester polyol B2 is then added, the process temperature is controlled at 60-70°C, and the reaction is carried out for 2-3 hours; sampling is performed for testing, the NCO content is adjusted to within a qualified range, the temperature is lowered to 45°C, the material is discharged, and the material is sealed for storage to obtain the B component.

[0066] When the product is manufactured, the mass ratio of component A to component B is 100:95, and the ratio of the molar number of total active hydroxyl groups in component A to the molar number of total isocyanate groups in component B is 1:1.

[0067] Comparative Example 2

[0068] Comparative Example 2 is a comparative example of Example 3, except that an excess of polyester polyol A2 is added to component A of this comparative example, and the transparent polyurethane resin stock solution consists of components A and B.

[0069] The component A comprises: 72.5 g of polyester polyol A1, 12 g of polyester polyol A2, 5 g of polyester polyol A3, 8 g of ethylene glycol, 1.5 g of propylene glycol and 1 g of a catalyst (a mixture of triethylenediamine and ethylene glycol in a mass ratio of 1:2); the above raw materials are mixed and stirred at 55° C. for 2 h, cooled to below 45° C., the hydroxyl value is adjusted to within the qualified range, and the mixture is sealed and stored to obtain component A.

[0070] The B component is as follows: 63g of isocyanate B1 (4,4-diphenylmethane diisocyanate) is added to a reactor, the temperature is maintained at 50°C, 0.003g of a side reaction inhibitor (phosphoric acid) is added, and the mixture is stirred for 15 minutes; 37g of polyester polyol B2 is then added, the process temperature is controlled at 60-70°C, and the reaction is carried out for 2-3 hours; sampling is performed for testing, the NCO content is adjusted to within a qualified range, the temperature is lowered to 45°C, the material is discharged, and the material is sealed for storage to obtain the B component.

[0071] When the product is manufactured, the mass ratio of component A to component B is 100:98, and the ratio of the molar number of total active hydroxyl groups in component A to the molar number of total isocyanate groups in component B is 1:1.

[0072] The transparent polyurethane resin stock solutions obtained in Examples 3 to 7 and Comparative Examples 1 to 3 are used to prepare polyurethane resin products, such as polyurethane outsoles or polyurethane shoe upper patches, and the preparation method is as follows:

[0073] Component A at 40°C and component B at 40°C (the contents of component A and component B are controlled so that the ratio of the total molar number of active hydrogen in the raw materials for preparing component A to the total molar number of isocyanate groups in the raw materials for preparing component B is 1:1) are mixed in a casting machine, injected into a 45°C mold, and reacted for 5 minutes; demolded, and aged in a 60°C oven for 12 hours to obtain a polyurethane resin product.

[0074] The polyurethane resin products obtained in Examples 3 to 7 and Comparative Examples 1 to 2 were tested for hardness according to the Shore A hardness standard for rubber; the transparency and surface appearance of the products were visually observed; and the tensile strength, tear strength, and elongation were measured according to the national standard GB / 528-2009. The results are listed in Table 1.

[0075] Table 1 is the performance test of Examples 3 to 7 and Comparative Examples 1 to 2

[0076]

[0077] The polyurethane compositions of Examples 3 to 7 of the present invention are used to prepare shoe sole products with good appearance and transparency. The effect of the nucleating agent is very obvious. Adding a certain amount of nucleating agent can effectively reduce the size of the crystalline region, increase light transmittance, and improve transparency. If the amount of nucleating agent added is too high, although the transparency is not affected, it will cause a significant decrease in tensile strength and tear strength.

Claims

1. A high-transmittance polyurethane resin stock solution, comprising component A and component B, characterized in that: The component A comprises the following raw materials by mass fraction: 75% to 90% of a polyester polyol A1 having a number average molecular weight of 1400 to 1600, 3% to 10% of a nucleating agent A2, 3% to 10% of a polyester polyol A3 having a number average molecular weight of 1800 to 2200, 1% to 10% of a difunctional chain extender, and 0.3% to 3% of a trihydroxy crosslinking agent; the component B comprises the following raw materials by mass fraction: 50% to 70% of an isocyanate B1 and 30% to 50% of a polyester polyol B2 having a molecular weight of 1800 to 2200; the ratio of the molar number of total active hydroxyl groups in the component A to the molar number of total isocyanate groups in the component B is 1:(0.98 to 1.02); The nucleating agent A2 is a hydroxyl-terminated polymer obtained by esterifying a mixture of (1,3:2,4)-dibenzylidene sorbitol and ethylene glycol with adipic acid, and has a number average molecular weight of 800-1000.

2. The high-transmittance polyurethane resin stock solution according to claim 1, characterized in that: The nucleating agent A2 is a hydroxyl-terminated polymer obtained by esterifying a mixture of 32% to 65% by mass of (1,3:2,4)-dibenzylidene sorbitol, 5% to 35% by mass of ethylene glycol, and 30% to 50% by mass of adipic acid, and has a number average molecular weight of 850 to 900.

3. The high-transmittance polyurethane resin stock solution according to claim 1 or 2, characterized in that: The preparation process of the nucleating agent A2 is as follows: start stirring and add ethylene glycol, (1,3:2,4)-dibenzylidene sorbitol and adipic acid to the reactor in sequence; after the addition is completed, heat it to 130-150° C. and stir to dehydrate for 2-5 hours, then heat it to 230-245° C. and stir to react for 4-7 hours; add an esterification catalyst, evacuate to a vacuum degree of -0.098 to -0.090 MPa, and react for 3-5 hours; take samples for testing, and obtain a nucleating agent A2 with an acid value of 0.2-0.8 mgKOH / g and a hydroxyl value of 124.6-132 mgKOH / g.

4. The high-transmittance polyurethane resin stock solution according to claim 1, characterized in that: The component A is composed of the following components in mass fraction: 75% to 85% polyester polyol A1, 4% to 9% nucleating agent A2, 3% to 8% polyester polyol A3, 1% to 9% difunctional chain extender and 0.3% to 2.5% trihydroxy crosslinker; the component B is composed of the following components in mass fraction: 50% to 68% isocyanate B1, 30% to 45% polyester polyol B2 and 0.001% to 0.005% side reaction inhibitor.

5. The high-transmittance polyurethane resin stock solution according to claim 1, 2 or 4, characterized in that: The polyester polyol A1 is a polyester polyol with a number average molecular weight of 1450 to 1550, which is obtained by polycondensing adipic acid with a combination of any two or three of ethylene glycol, 1,4-butanediol, and diethylene glycol through an esterification reaction; The polyester polyol A3 is a polyester polyol having a number average molecular weight of 1900 to 2100, which is prepared by esterifying a combination of any two or three of ethylene glycol, 1,4-butanediol, and dipropylene glycol with adipic acid; The polyester polyol B2 is prepared by esterification and polycondensation of the following components by mass fraction: 3% to 19% ethylene glycol, 3% to 18% 1,4-butanediol, 2% to 25% diethylene glycol, and 60% to 64% adipic acid; The isocyanate B1 is any one of diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, toluene diisocyanate or naphthalene diisocyanate, or a combination of at least two thereof; The difunctional chain extender is at least one of ethylene glycol, 1,4-butanediol, 1,3-propylene glycol or 1,6-hexanediol; and the trihydroxy crosslinking agent is at least one of glycerol, trimethylolpropane or 1,2,6-hexanetriol.

6. The high-transmittance polyurethane resin stock solution according to claim 5, characterized in that: The polyester polyol A1 is prepared by polycondensation of 3% to 19% by mass of ethylene glycol, 3% to 18% by mass of 1,4-butanediol, 2% to 25% by mass of diethylene glycol, and 60% to 64% by mass of adipic acid through esterification reaction.

7. The high-transmittance polyurethane resin stock solution according to claim 1, 2 or 4, characterized in that: The raw materials for preparing component A also include a catalyst with a mass fraction of 0.7% to 3%, and the catalyst is a mixture of triethylenediamine and ethylene glycol in a mass ratio of 1:(2-3); the side reaction inhibitor is phosphoric acid and / or benzoyl chloride.

8. The method for preparing a high-transmittance polyurethane resin stock solution according to claim 1, 2 or 4, characterized in that: The steps include: (1) Mixing and stirring the raw materials of the A component at 50-60° C. for 1.0-2.5 hours until uniform, cooling to 40-45° C., and further mixing and stirring for 1.0-1.5 hours to adjust the hydroxyl value to within the qualified range to obtain the A component; (2) The raw materials for preparing component B are stirred and mixed, and reacted at a temperature of 60-70° C. for 2-3 hours to adjust the NCO content of component B to be within the qualified range to obtain component B.

9. The use of the high-transmittance polyurethane resin stock solution according to claim 1, 2 or 4, characterized in that: Used to prepare polyurethane resin products.

10. The use of the high-transmittance polyurethane resin stock solution according to claim 9, characterized in that: The method comprises the following steps: fully mixing the component A and the component B, injecting the mixture into a mold for reaction molding, demolding, and aging to obtain the polyurethane resin product; before mixing, the temperatures of the component A and the component B are respectively maintained at 40-45° C.; the reaction temperature in the mold is 45-55° C., and the reaction time is 3-5 minutes; the aging temperature is 55-70° C., and the aging time is 6-24 hours.

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