Polyurethane stock solution as well as low-density high-resilience polyurethane resin and application thereof

Abstract

The invention relates to a polyurethane stock solution as well as low-density high-resilience polyurethane resin and application thereof, the polyurethane stock solution comprises a component A and a component B, the component A contains polyester polyol, a cross-linking agent and a chain extender, and the component B comprises a polyurethane prepolymer obtained by reaction of polyether polyol and polyisocyanate and a surfactant. The low-density high-resilience polyurethane resin prepared from the polyurethane stock solution is prepared by mixing a component A and a component B, reacting in the presence of a foaming agent, foaming and forming, the ratio of the total molar weight of groups having reaction activity on NCO in the component A to the molar weight of NCO in the component B is 0.95-1.05, the molding density of the prepared low-density high-resilience polyurethane resin is 0.15-0.25 g / ml, and the hardness is 40-50 C; the low-density high-resilience polyurethane resin is applied to a shoe insole; the resin is applied to shoe soles, especially shoe insole materials, and solves the problems of low density, high resilience, slow demolding time, low hardness, poor physical properties, unstable raw material storage and the like.

Description

Technical Field

[0001] The invention relates to a polyurethane stock solution and to a low-density high-rebound polyurethane resin prepared from the polyurethane stock solution and application thereof. Background Art

[0002] Polyurethane microporous elastomers have excellent mechanical properties, anti-slip properties and chemical resistance, and are widely used in the field of shoe sole materials. On the one hand, the polyurethane stock solution used to prepare polyurethane microporous elastomers generally has storage problems: for example, components containing isocyanate prepolymers have problems such as short shelf life and whitening and deterioration; components containing components that are reactive to isocyanates have water absorption problems, etc. On the other hand, it is difficult for the prepared polyurethane microporous elastomer to simultaneously take into account the problems of low molding density, high resilience and high peel strength, especially the midsole components of shoes that mainly play the role of compression resistance and shock absorption, which have higher requirements for material resilience and density: the molding density of conventional polyester polyurethane microporous elastomers is greater than 0.30g / ml, and the rebound rate of falling balls is about 20-30%; although there are currently high-rebound polyurethane microporous elastomer products, for example, the rebound rate of all-polyether polyurethane can be greater than 40%, but the molding density is generally higher than 0.30g / ml, and the split-layer tearing is only maintained at 1.2-1.5kN / m; if the density of the molded body is reduced, it will cause problems such as peeling of the finished product surface, slow molding maturation, and poor mechanical properties. Summary of the invention

[0003] Technical problem: In order to solve the above-mentioned technical defects, the purpose of the present invention is to provide a polyurethane stock solution and a low-density high-rebound polyurethane resin prepared by using the polyurethane stock solution. The resin is used for soles, especially midsole materials, and solves the problems of slow demoulding time, low hardness, poor physical properties, unstable raw material storage, etc. of low-density high-rebound.

[0004] Technical solution: The polyurethane stock solution described in the present invention includes component A and component B, wherein the component A contains polyester polyol, a crosslinking agent and a chain extender, and the component B includes a polyurethane prepolymer obtained by reacting a polyether polyol with a polyisocyanate and a surfactant.

[0005] The component A comprises 85-95% by weight of polyester polyol, 0.3-5% by weight of crosslinking agent, and 2-10% by weight of chain extender; the component B comprises 98-99.5% by weight of polyurethane prepolymer and 0.5-2% by weight of surfactant.

[0006] In the component A, the polyester polyol includes aliphatic polyester polyol and / or grafted polyester polyol; the number average molecular weight of the polyester polyol is 1000 to 4000 g / mol;

[0007] The aliphatic polyester polyol is obtained by polycondensation of a dibasic aliphatic carboxylic acid and an aliphatic diol;

[0008] The carbon number of the aliphatic dicarboxylic acid is C4-C8, including one or more of succinic acid, glutaric acid, adipic acid, pimelic acid, and suberic acid;

[0009] The carbon number of the aliphatic diol is C4-C10, including one or more of diethylene glycol, butanediol, pentanediol, hexanediol, neopentyl glycol, heptanediol, octanediol, nonanediol and decanediol.

[0010] The grafted polyester polyol includes styrene-grafted polyester polyol, which is obtained by polymerizing aliphatic polyester polyol and styrene-containing monomers in the presence of an initiator and a chain transfer agent;

[0011] The styrene-containing monomer includes at least one of styrene and methyl styrene;

[0012] The initiator is a free radical initiator, including one or more of benzoyl oxide, di-tert-butyl cyclohexyl peroxide, di-tert-butyl cyclopentane peroxide, and azobisisobutyronitrile;

[0013] The chain transfer agent includes one or more of toluene, ethylbenzene, hexane, butanol, isobutanol, isopropanol, ethyl acetate, mercaptan, and dodecyl alcohol.

[0014] In the component A, the crosslinking agent is a small molecule polyol with a hydroxyl functionality of 4 or more, and a hydroxyl-terminated small molecule polyol is obtained by reacting an alcohol amine containing a secondary amine with a polyisocyanate;

[0015] The alcohol amine containing secondary amine includes at least one of diethanolamine, dipropanolamine and dibutanolamine;

[0016] The polyisocyanate includes one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, polymethylene polyphenyl diisocyanate, naphthalene diisocyanate and isomers and / or derivatives and / or modified polymers thereof.

[0017] In the component A, the chain extender includes a diol with carbon atoms of C2 to C6, including one or more of diethylene glycol, ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol.

[0018] In the B component, the polyether polyol includes polytetramethylene ether polyol, and the number average molecular weight of the polyether polyol is 1000-4000 g / mol.

[0019] In the B component, the polyisocyanate comprises one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, polymethylene polyphenyl diisocyanate, naphthalene diisocyanate and isomers and / or derivatives and / or modified polymers thereof; the NCO mass content of the polyurethane prepolymer is 15-25%, calculated based on the mass of the prepolymer.

[0020] The low-density high-resilience polyurethane resin prepared from the polyurethane stock solution of the present invention comprises mixing component A and component B, reacting in the presence of a foaming agent, foaming, and molding;

[0021] The ratio of the total molar amount of the groups reactive to NCO in the component A to the molar amount of NCO in the component B is 0.95 to 1.05, and the molding density of the prepared low-density high-resilience polyurethane resin is 0.15 to 0.25 g / ml, and the hardness is 40 to 50C;

[0022] The low-density high-rebound polyurethane resin is applied to the midsole of shoes, including the midsole materials of safety shoes, sports shoes and casual shoes.

[0023] Beneficial effect: The density of the shoe midsole material prepared by the low-density high-rebound polyurethane resin prepared by the polyurethane stock solution of the present invention has been broken through to below 0.25g / ml, which solves the problems of slow demoulding time, low hardness, poor physical properties, unstable raw material storage, etc. of low-density high-rebound, realizes the mass production stability of the assembly line, and improves the competitiveness of polyurethane materials in the field of shoe soles. DETAILED DESCRIPTION

[0024] The polyurethane stock solution of the present invention comprises component A and component B, wherein the component A comprises polyester polyol, a crosslinking agent and a chain extender, and the component B comprises a polyurethane prepolymer obtained by reacting a polyether polyol with a polyisocyanate, and a surfactant; wherein the crosslinking agent has a hydroxyl functionality of 4 or more;

[0025] In component A:

[0026] The polyester polyols include aliphatic polyester polyols and / or grafted polyester polyols;

[0027] The aliphatic polyester polyol is obtained by polycondensation of a dibasic aliphatic carboxylic acid and an aliphatic diol;

[0028] The carbon number of the aliphatic dicarboxylic acid is C4-C8, including one or more of succinic acid, glutaric acid, adipic acid, pimelic acid, and suberic acid;

[0029] Preferably, the aliphatic dibasic acid comprises adipic acid;

[0030] The carbon number of the aliphatic diol is C4-C10, including one or more of diethylene glycol, butanediol, pentanediol, hexanediol, neopentyl glycol, heptanediol, octanediol, nonanediol, and decanediol;

[0031] Preferably, the carbon number of the aliphatic diol is C4-C6, including one or more of butanediol, pentanediol and hexanediol;

[0032] In some examples of the present invention, the aliphatic polyester polyol includes one or more of polybutylene adipate polyol, polypentylene adipate polyol, polyhexylene adipate polyol, and polypentylene adipate polyol;

[0033] The grafted polyester polyol includes styrene-grafted polyester polyol, which is obtained by polymerizing aliphatic polyester polyol and styrene-containing monomers in the presence of an initiator and a chain transfer agent;

[0034] The styrene-containing monomer includes at least one of styrene and methyl styrene;

[0035] The initiator is a free radical initiator, including one or more of benzoyl oxide, di-tert-butyl cyclohexyl peroxide, di-tert-butyl cyclopentane peroxide, and azobisisobutyronitrile;

[0036] The chain transfer agent includes one or more of toluene, ethylbenzene, hexane, butanol, isobutanol, isopropanol, ethyl acetate, mercaptan, and dodecyl alcohol;

[0037] The number average molecular weight of the polyester polyol is 1000 to 4000 g / mol;

[0038] In some examples of the present invention, the styrene-grafted polyester polyol includes one or more of styrene-grafted polybutylene adipate polyol, styrene-grafted polyhexane adipate polyol, and styrene-grafted polypentane adipate polyol;

[0039] In some examples of the present invention, the polyester polyol comprises a mixture of aliphatic polyester polyol and styrene grafted polyester polyol, and the mass ratio of the aliphatic polyester polyol to the styrene grafted polyester polyol is 3:5 to 7:2;

[0040] In the present invention, the ester bond content density in the polyester polyol is relatively low, which can improve the flexibility of the polyester polyol to a certain extent, and maintain the high resilience characteristics of the polyurethane without reducing the mechanical properties.

[0041] The crosslinking agent is a small molecule polyol with a hydroxyl functionality of 4 or more, and a hydroxyl-terminated small molecule polyol is obtained by reacting an alcohol amine containing a secondary amine with a polyisocyanate;

[0042] The alcohol amine containing secondary amine includes at least one of diethanolamine, dipropanolamine and dibutanolamine;

[0043] The polyisocyanate includes one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, polymethylene polyphenyl diisocyanate, naphthalene diisocyanate and isomers and / or derivatives and / or modified polymers thereof;

[0044] In the present invention, the polyisocyanate-modified polymer includes polyisocyanates modified with carbodiimide, for example, carbodiimide-modified diphenylmethane diisocyanate (liquefied diphenylmethane diisocyanate);

[0045] The reactivity of secondary amines to NCO is significantly higher than that of hydroxyl groups. In some embodiments of the present invention, by controlling the molar amount of the secondary amine group in the alcohol amine to be higher than the molar amount of NCO in the polyisocyanate, it is possible to ensure that the hydroxyl group does not participate in the reaction, thereby obtaining a crosslinking agent with a hydroxyl functionality of 4 or more;

[0046] In the present invention, the secondary amine in the alcohol amine reacts with the NCO in the polyisocyanate to obtain a crosslinking agent with a hydroxyl functionality of 4 or more, which can effectively improve the split tear and resilience of the polyurethane resin, while increasing the hardness and shaping aging time, and improving the surface of the finished product;

[0047] The chain extender includes a diol with carbon atoms of C2 to C6, including one or more of diethylene glycol, ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol;

[0048] Optionally, a catalyst may be added to the component A to accelerate the reaction rate of the material A and the material B, for example, an amine catalyst and / or a metal catalyst;

[0049] The amine catalyst includes one or more of triethylenediamine, tetramethyldiethylenetriamine, and pentamethyldipropylenetriamine;

[0050] The metal catalyst includes one or more of dibutyltin dilaurate, stannous octoate, zinc isooctanoate, bismuth isooctanoate, potassium acetate, and potassium isooctanoate;

[0051] In component B:

[0052] The polyether polyol includes polytetramethylene ether polyol, and the number average molecular weight of the polyether polyol is 1000-4000 g / mol;

[0053] One or more of the polyisocyanates diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, polymethylene polyphenyl diisocyanate, naphthalene diisocyanate, and isomers and / or derivatives and / or modified polymers thereof;

[0054] The NCO mass content of the polyurethane prepolymer is 15-25%, calculated based on the mass of the prepolymer;

[0055] The surfactant includes polysiloxane. For example, the polysiloxane includes at least one of a polysiloxane-polyoxyalkylene block copolymer and a polyether-modified polysiloxane polymer. Furthermore, the polysiloxane has no reaction activity to the polyurethane prepolymer.

[0056] In the present invention, by adding a surfactant to component B, the problem of short shelf life and easy whitening of component B is effectively solved, thereby improving the storage stability of component B;

[0057] Optionally, a side reaction inhibitor may be added to the material B to slow down the occurrence of side reactions;

[0058] As an example, the side reaction inhibitor is phosphoric acid.

[0059] Furthermore, the A component and / or the B component may also be optionally added with auxiliary agents commonly used in the art, such as plasticizers, foam leveling agents, cell opening agents, anti-yellowing agents, anti-folding agents, and the like.

[0060] Furthermore, the component A comprises 85-95% of polyester polyol, 0.3-5% of cross-linking agent, and 2-10% of chain extender;

[0061] Furthermore, the B component includes 98-99.5% of polyurethane prepolymer and 0.5-2% of surfactant.

[0062] The low-density high-resilience polyurethane resin of the present invention comprises mixing component A and component B, reacting in the presence of a foaming agent, foaming, and molding;

[0063] Wherein, the ratio of the total molar amount of the groups reactive to NCO in the A component to the molar amount of NCO in the B component is 0.95 to 1.05, preferably 1 to 1.05;

[0064] Furthermore, there is no special requirement for the content of the foaming agent, and it can be added according to the demand to ensure that the A component and the B component can be fully foamed and formed after mixing;

[0065] The foaming agent includes water;

[0066] The molding density of the prepared low-density high-rebound polyurethane resin is 0.15-0.25 g / ml, and the hardness is maintained at 30-60C.

[0067] In the present invention, the foaming agent can be added simultaneously when the components A and B are mixed, or can be first added to the component A and then mixed with the component B;

[0068] As an example, the blowing agent is added to the A component;

[0069] As an example, the preparation method of the low-density high-resilience polyurethane resin is as follows:

[0070] Component A and component B are mixed at a temperature of 40°C to 60°C and injected into a molding mold to react for 5 to 10 minutes, demolded, and aged at a temperature of 60°C to 70°C for 10 to 24 hours to obtain a molded low-density high-resilience polyurethane resin.

[0071] Furthermore, component A and component B can be directly mixed by a pouring machine, and the mixture is directly injected into a mold for molding, so as to simplify the preparation steps;

[0072] Further, the total molar amount of the groups reactive to NCO in component A and the molar amount of NCO in component B can be directly set to a theoretical ratio of 1, mixed and injected into a molding die for reaction molding;

[0073] In the actual polyurethane preparation process, the ratio of the total molar amount of the groups reactive to NCO in component A to the molar amount of NCO in component B may fluctuate, and the molar ratio range of 0.95 to 1.05 does not affect the molding of the polyurethane resin;

[0074] The low-density high-rebound polyurethane resin is applied to shoe soles, including midsole materials of safety shoes, sports shoes and casual shoes. According to the requirements, the molding mold of the polyurethane resin can directly adopt the midsole mold, and the midsole product can be obtained after molding and maturation.

[0075] The technical solution of the present invention is further described below according to specific embodiments. The protection scope of the present invention is not limited to the following embodiments, which are listed only for illustrative purposes and do not limit the present invention in any way.

[0076] (1) Preparation of cross-linking agent: preheat diethanolamine to 70-75°C, add phosphoric acid as an optional side reaction inhibitor, stir evenly, add polyisocyanate dropwise, and after the addition is complete, continue the reaction at 70-75°C for 1-2 hours to obtain the cross-linking agent.

[0077] (2) Preparation of component A: The polyester polyol, the crosslinking agent, the chain extender, the optional catalyst and the foaming agent are fully stirred and mixed at room temperature to obtain component A.

[0078] (3) Preparation of component B: react polyether polyol, polyisocyanate and optional side reaction inhibitor phosphoric acid at 65-80° C. to obtain a polyurethane prepolymer, add a surfactant and mix well to obtain component B, and seal and store.

[0079] Crosslinking agent 1: diethanolamine and liquefied diphenylmethane diisocyanate react to obtain a small molecule polyol containing urea groups with an average hydroxyl functionality of 4;

[0080] Crosslinking agent 2: diethanolamine and diphenylmethane diisocyanate react to obtain a small molecule polyol containing urea groups with an average hydroxyl functionality of 4;

[0081] Crosslinking agent 3: Dipropanolamine and diphenylmethane diisocyanate react to obtain a small molecule polyol containing urea groups with an average hydroxyl functionality of 4.

[0082] Polyurethane prepolymer 1: obtained by reacting polytetramethylene ether polyol-Mn2000 and diphenylmethane diisocyanate, with a total NCO mass content of 20%;

[0083] Polyurethane prepolymer 2: obtained by reacting polyoxypropylene polyol-Mn2000 and diphenylmethane diisocyanate, with a total NCO content of 20%;

[0084] Polyurethane prepolymer 3: obtained by reacting polybutylene adipate polyol-Mn2000 and diphenylmethane diisocyanate, with a total NCO mass content of 20%.

[0085] Example 1

[0086] Component A contains 92.5kg polyester polyol (polybutylene adipate polyol-Mn2000), 2kg crosslinker 1, 3kg ethylene glycol, 1kg blowing agent water, and 1.5kg catalyst triethylene diamine;

[0087] Component B contains 99 kg of polyurethane prepolymer 1 and 1 kg of polysiloxane.

[0088] Example 2

[0089] Component A contains 90kg polyester polyol (polyhexane adipate polyol-Mn3000), 3kg crosslinker 2, 4.5kg ethylene glycol, 1kg blowing agent water, and 1.5kg catalyst triethylene diamine;

[0090] Component B contains 98 kg of polyurethane prepolymer and 1,2 kg of polysiloxane.

[0091] Example 3

[0092] Component A contains 85kg polyester polyol (polybutylene adipate pentanediol polyol-Mn2000), 4kg crosslinker 3, 8.5kg butanediol, 1kg blowing agent water, and 1.5kg catalyst triethylenediamine;

[0093] Component B contains 99.5 kg of polyurethane prepolymer 1 and 0.5 kg of polysiloxane.

[0094] Example 4

[0095] Component A contains 92.5kg polyester polyol (polystyrene modified polybutylene adipate polyol-Mn2000), 2kg crosslinker 1, 3kg ethylene glycol, 1kg blowing agent water, and 1.5kg catalyst triethylene diamine;

[0096] Component B contains 99 kg of polyurethane prepolymer 1 and 1 kg of polysiloxane.

[0097] Example 5

[0098] Component A contains 92.5kg polyester polyol (polyethylene adipate polyol-Mn2000), 2kg crosslinker 1, 3kg ethylene glycol, 1kg blowing agent water, and 1.5kg catalyst triethylene diamine;

[0099] Component B contains 99 kg of polyurethane prepolymer 1 and 1 kg of polysiloxane.

[0100] Example 6

[0101] Component A contains 92.5kg polyester polyol (polybutylene adipate polyol-Mn2000), 2kg crosslinker 1, 3kg ethylene glycol, 1kg blowing agent water, and 1.5kg catalyst triethylene diamine;

[0102] Component B contains 99 kg of polyurethane prepolymer 2 and 1 kg of polysiloxane.

[0103] Example 7

[0104] Component A contains 92.5 kg polyester polyol (polybutylene adipate polyol-Mn2000 and styrene-modified polybutylene adipate polyol-Mn2000 in a mass ratio of 3:5), 2 kg crosslinking agent 1, 3 kg ethylene glycol, 1 kg foaming agent water, and 1.5 kg catalyst triethylene diamine;

[0105] Component B contains 99 kg of polyurethane prepolymer 1 and 1 kg of polysiloxane.

[0106] Example 8

[0107] Component A contains 92.5 kg of polyester polyol (polyhexanediol adipate polyol-Mn3000 and styrene-modified polyhexanediol adipate polyol-Mn3000 in a mass ratio of 7:5), 2 kg of crosslinking agent 1, 4.5 kg of ethylene glycol, 1 kg of foaming agent water, and 1.5 kg of catalyst triethylenediamine;

[0108] Component B contains 99 kg of polyurethane prepolymer 1 and 1 kg of polysiloxane.

[0109] Example 9

[0110] Component A contains 92.5kg polyester polyol (polybutylene adipate polyol-Mn2000), 2kg diethanolamine, 3kg ethylene glycol, 1kg blowing agent water, and 1.5kg catalyst triethylenediamine;

[0111] Component B contains 99 kg of polyurethane prepolymer 1 and 1 kg of polysiloxane.

[0112] Example 10

[0113] Component A contains 92.5kg polyester polyol (polybutylene adipate polyol-Mn2000), 2kg glycerol, 3kg ethylene glycol, 1kg blowing agent water, and 1.5kg catalyst triethylenediamine;

[0114] Component B contains 99 kg of polyurethane prepolymer 1 and 1 kg of polysiloxane.

[0115] Embodiment 11

[0116] Component A contains 92.5kg polyester polyol (polybutylene adipate polyol-Mn2000), 2kg crosslinker 3, 3kg ethylene glycol, 1kg blowing agent water, and 1.5kg catalyst triethylene diamine;

[0117] Component B contains 99 kg of polyurethane prepolymer 1 and 1 kg of polysiloxane.

[0118] Comparative Example 1

[0119] The difference from Example 1 is that no crosslinking agent is added to component A.

[0120] Comparative Example 2

[0121] The difference from Example 1 is that the polyester polyol in component A is replaced by polytetramethylene ether polyol-Mn2000 of equal mass.

[0122] Comparative Example 3

[0123] The difference from Example 1 is that the polyether polyol in component B is replaced by an equal mass of polybutylene adipate polyol-Mn2000.

[0124] Comparative Example 1

[0125] The difference from Example 1 is that the surfactant polysiloxane is not added to the B component.

[0126] Preparation Example

[0127] According to the above-mentioned embodiments and comparative examples, component A and component B are mixed by a pouring machine, and the theoretical ratio of the total molar amount of groups reactive to NCO in material A to the molar amount of NCO in material B is controlled to be 1:1, and then injected into a mold for molding and aging to obtain a molded polyurethane resin, wherein the mass of each preparation example and comparative preparation example injected into the mold is controlled to be consistent, so that the density of the polyurethane resin remains stable for comparison of subsequent performance tests.

[0128] The above polyurethane resin was subjected to the following performance tests, and the performance data obtained from the tests are as follows:

[0129]

[0130]

[0131]

Claims

1. A polyurethane stock solution, characterized in that The polyurethane stock solution comprises component A and component B, wherein the component A contains polyester polyol, a crosslinking agent and a chain extender, and the component B comprises a polyurethane prepolymer obtained by the reaction of polyether polyol and polyisocyanate and a surfactant.

2. A polyurethane stock solution according to claim 1, characterized in that: The component A comprises 85-95% by weight of polyester polyol, 0.3-5% by weight of crosslinking agent, and 2-10% by weight of chain extender; the component B comprises 98-99.5% by weight of polyurethane prepolymer and 0.5-2% by weight of surfactant.

3. A polyurethane stock solution according to claim 1 or 2, characterized in that: In the component A, the polyester polyol includes aliphatic polyester polyol and / or grafted polyester polyol; the number average molecular weight of the polyester polyol is 1000-4000 g / mol.

4. A polyurethane stock solution according to claim 3, characterized in that: The aliphatic polyester polyol is obtained by polycondensation of a dibasic aliphatic carboxylic acid and an aliphatic diol; The carbon number of the aliphatic dicarboxylic acid is C4-C8, including one or more of succinic acid, glutaric acid, adipic acid, pimelic acid, and suberic acid; The carbon number of the aliphatic diol is C4-C10, including one or more of diethylene glycol, butanediol, pentanediol, hexanediol, neopentyl glycol, heptanediol, octanediol, nonanediol and decanediol.

5. The polyurethane stock solution according to claim 3, characterized in that: The grafted polyester polyol includes styrene-grafted polyester polyol, which is obtained by polymerizing aliphatic polyester polyol and styrene-containing monomers in the presence of an initiator and a chain transfer agent; The styrene-containing monomer includes at least one of styrene and methyl styrene; The initiator is a free radical initiator, including one or more of benzoyl oxide, di-tert-butyl cyclohexyl peroxide, di-tert-butyl cyclopentane peroxide, and azobisisobutyronitrile; The chain transfer agent includes one or more of toluene, ethylbenzene, hexane, butanol, isobutanol, isopropanol, ethyl acetate, mercaptan, and dodecyl alcohol.

6. A polyurethane stock solution according to claim 1 or 2, characterized in that: In the component A, the crosslinking agent is a small molecule polyol with a hydroxyl functionality of 4 or more, and a hydroxyl-terminated small molecule polyol is obtained by reacting an alcohol amine containing a secondary amine with a polyisocyanate; The alcohol amine containing secondary amine includes at least one of diethanolamine, dipropanolamine and dibutanolamine; The polyisocyanate includes one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, polymethylene polyphenyl diisocyanate, naphthalene diisocyanate and isomers and / or derivatives and / or modified polymers thereof.

7. A polyurethane stock solution according to claim 1 or 2, characterized in that: In the component A, the chain extender includes a diol with carbon atoms of C2 to C6, including one or more of diethylene glycol, ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol.

8. A polyurethane stock solution according to claim 1 or 2, characterized in that: In the B component, the polyether polyol includes polytetramethylene ether polyol, and the number average molecular weight of the polyether polyol is 1000-4000 g / mol.

9. A polyurethane stock solution according to claim 1 or 2, characterized in that: In the B component, the polyisocyanate comprises one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, polymethylene polyphenyl diisocyanate, naphthalene diisocyanate and isomers and / or derivatives and / or modified polymers thereof; the NCO mass content of the polyurethane prepolymer is 15-25%, calculated based on the mass of the prepolymer.

10. A low-density high-resilience polyurethane resin prepared from the polyurethane stock solution according to claim 1 or 2, characterized in that: The low-density high-resilience polyurethane resin comprises mixing component A and component B, reacting in the presence of a foaming agent, foaming, and molding; The ratio of the total molar amount of the groups reactive to NCO in the component A to the molar amount of NCO in the component B is 0.95 to 1.05, and the molding density of the prepared low-density high-resilience polyurethane resin is 0.15 to 0.25 g / ml, and the hardness is 40 to 50C; The low-density high-rebound polyurethane resin is applied to the midsole of shoes.

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