A heat-insulating and foamed shoe material containing silica aerogel

Abstract

This application relates to the technical field of heat-insulating shoe materials, and specifically provides a heat-insulating foamed shoe material containing silica aerogel. The heat-insulating foamed shoe material of this application, by weight parts, the raw material components include 100 parts of TPU, 1-10 parts of silica aerogel, and 0.2-5 parts of a compatibilizing agent; the compatibilizing agent is a polysiloxane-modified linear-structured polyurethane; the heat-insulating foamed shoe material is prepared by a supercritical foaming technology. A compatibilizing agent is added to the heat-insulating foamed shoe material of this application to promote the compatibility between silica aerogel and TPU.

Description

Technical Field

[0001] The present application relates to the technical field of thermal insulation shoe materials, and in particular, to a thermal insulation foam shoe material containing silica aerogel. Background Art

[0002] Supercritical foaming shoe materials are characterized by light weight, good wear resistance and good resilience, and have been widely used in various sports shoes. Silica aerogel has good thermal insulation properties. Adding silica aerogel to shoe materials can improve the thermal insulation properties of shoes. Combining silica aerogel with supercritical foaming shoe materials can combine the advantages of both. Summary of the invention

[0003] The applicant found that due to the fine pores and high pore density of supercritical foaming, the pore diameter is less than 10 μm and the pore density is generally 10 9 -10 15 g / cm 3 Therefore, silica aerogel is required to have very fine particles, with a particle size not exceeding 10μm, or even not exceeding 5μm. Ultrafine silica aerogel particles are inorganic materials, and shoe materials such as TPU and EVA are organic polymer materials. The compatibility of ultrafine silica aerogel particles with foamed shoe materials such as TPU is poor, which results in the inability to effectively disperse silica aerogel, restricting the improvement of thermal insulation performance. In order to solve the above technical problems, the present application provides a thermal insulation foamed shoe material containing silica aerogel.

[0004] This application adopts the following technical solutions:

[0005] A thermal insulation foam shoe material containing silica aerogel, wherein the raw material components include, by weight, 100 parts of TPU, 1-10 parts of silica aerogel and 0.2-5 parts of a compatibility aid;

[0006] The compatibility aid is a polysiloxane-modified linear structure polyurethane;

[0007] The thermal insulation foamed shoe material is prepared by adopting supercritical foaming technology.

[0008] Preferably, the compatibilizer is obtained by reacting a diol raw material with a diisocyanate;

[0009] The diol raw material consists of double-terminal hydroxyalkyl polysiloxane, non-silicon polymer diol and diol chain extender.

[0010] More preferably, the molar ratio of the diol raw material to the diisocyanate is 1:0.9-1.

[0011] More preferably, the molar proportion of the dual-terminal hydroxyalkyl polysiloxane in the diol raw material is 60-90%.

[0012] More preferably, the molar proportion of the non-silicon polymer diol in the diol raw material is 0-30%.

[0013] More preferably, the molar proportion of the diol chain extender in the diol raw material is 10-20%.

[0014] More preferably, the general formula of the dihydroxyalkyl polysiloxane is HOR 1 Me2SiO(SiOMe2) m (SiOMeR 2 ) n SiMe2R 1 OH, wherein, R 1 is selected from C2-C8 alkylene groups, R 2 is selected from C1-C18 hydrocarbon groups, C1-C18 substituted hydrocarbon groups or aromatic groups and their derivatives, Me represents a methyl group, m = 20-300, n = 3-20.

[0015] Further preferably, the R 2 is selected from -OR 3 or -CH2CH2Me x Si(OR 4 ) 3-x , wherein R 3 and R 4 are independently selected from C1-C4 alkyl groups, x = 0-1, Me represents a methyl group.

[0016] Preferably, the average particle size of the silica aerogel does not exceed 5 μm.

[0017] Preferably, the raw material components are pre-mixed to form pre-mixed particles.

[0018] In summary, the present application has the following beneficial effects:

[0019] 1. In order to solve the compatibility problem between TPU and ultrafine particles of silica aerogel, a linear-structured polyurethane containing a polysiloxane structure is added. The main chain of the polysiloxane segment in the linear-structured polyurethane is -Si-O-, which is the same as the main chain -Si-O- of the silica aerogel. The polysiloxane segment has good compatibility with the silica aerogel. The polyurethane structure in the linear-structured polyurethane is similar to the structure of TPU and has good compatibility with TPU. Therefore, the compatibility aid in the present application has a polysiloxane segment with good compatibility with the silica aerogel and a polyurethane segment with good compatibility with TPU. Therefore, it can play a good compatibility role for the silica aerogel and TPU, improve the dispersibility of the silica aerogel in TPU, and exert the heat insulation and heat preservation effect of the silica aerogel.

[0020] 2. In the compatibilizing agent structure of this application, the side chain of the polysiloxane structure contains hydrolyzable alkoxy groups, which can undergo a condensation reaction with the hydroxyl groups on the surface of silica aerogel during the processing, further improving the compatibility between silica aerogel and TPU, and also enhancing the dispersion stability of silica aerogel in TPU. Detailed implementation manners

[0021] In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below.

[0022] Throughout this specification, unless otherwise specifically stated, the terms used herein should be understood to have the meanings as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention pertains. In case of any contradiction, this specification shall prevail.

[0023] This application proposes a heat-insulating foamed shoe material containing silica aerogel. By weight, the raw material components include 100 parts of TPU, 1 - 10 parts of silica aerogel, and 0.2 - 5 parts of a compatibilizing agent.

[0024] The above-mentioned compatibilizing agent is a polysiloxane-modified linear-structured polyurethane, where the polysiloxane segment is located on the main chain of the linear-structured polyurethane; the linear-structured polyurethane means that the polyurethane polymer chain is a linear structure without cross-linked or branched structures.

[0025] The above-mentioned heat-insulating foamed shoe material is prepared by a supercritical foaming technology.

[0026] In this application, further, the weight of the compatibilizing agent is 30 - 60% of the weight of the silica aerogel.

[0027] In this application, the supercritical foaming technology can adopt the following process: Mix the above-mentioned raw material components, heat and melt them to be uniformly mixed to obtain pre-mixed particles; place the pre-mixed particles in a high-pressure autoclave and seal it, and saturate the pre-mixed particles with a supercritical fluid (such as supercritical CO2, supercritical N2, etc., with a pressure of 15 - 30 MPa) (at a temperature of 50 - 90 °C for 2 - 5 h), relieve the pressure to obtain a swollen part; take out the swollen part and place it in a constant-temperature device at 80 - 120 °C for 15 - 30 minutes to obtain the heat-insulating foamed shoe material.

[0028] In a preferred embodiment of the present application, the compatibilizing agent is obtained by reacting a diol raw material with a diisocyanate; the diol raw material is composed of a double-ended hydroxyalkyl polysiloxane, a non-silicon polymer diol, and a diol chain extender. By reacting the diol raw material with the diisocyanate, the structure of the obtained product is a linear structure. The reaction of the double-ended hydroxyalkyl polysiloxane with the isocyanate can introduce a polysiloxane chain segment structure into the polyurethane structure. In the present application, the non-silicon polymer diol refers to a polymer diol that does not contain silicon atoms, such as polyether diols, polyester diols and other raw materials commonly used in polyurethane preparation. The average molecular weight of the polyether diol and the polyester diol can be 200-2000. In the present application, the diisocyanate is not particularly limited and can be selected from toluene diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, diphenylmethane-4,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, hexamethylene diisocyanate, etc.

[0029] The compatibilizing agent of the present application can be prepared by the following method: After drying the double-ended hydroxyalkyl polysiloxane and the non-silicon polymer diol to remove water, add them to a reaction vessel, add the diisocyanate and react at 80-100 °C for 1 hour, add an organotin catalyst (such as dibutyltin dilaurate, stannous octoate, etc.) about 0.1% of the total weight of the compatibilizing agent raw materials, continue to react until the theoretical isocyanate content, then add the diol chain extender, and continue to react for 2-5 hours, and cool to obtain.

[0030] In a more preferred embodiment of the present application, the molar ratio of the diol raw material to the diisocyanate is 1:0.9-1. Controlling the molar ratio of the diol raw material to the diisocyanate within the above range can make the isocyanate groups react completely basically, and the end groups of the polyurethane are hydroxyl groups. Further preferably, the molar ratio of the diol raw material to the diisocyanate is 1:0.92-1. For example, the molar ratio can be 1:0.92, 1:0.93, 1:0.94, 1:0.95, 1:0.96, 1:0.97, 1:0.98, 1:0.99, 1:1, etc.

[0031] In a more preferred embodiment of the present application, the molar proportion of the double-ended hydroxyalkyl polysiloxane in the diol raw material is 60-90%. When the double-ended hydroxyalkyl polysiloxane is within the above range, the content of the polysiloxane structure in the obtained compatibilizing agent structure is relatively high, and it can have good compatibility with the ultrafine silica aerogel. Further preferably, the molar proportion of the double-ended hydroxyalkyl polysiloxane in the diol raw material is 60-80%. For example, the molar proportion of the double-ended hydroxyalkyl polysiloxane in the diol raw material can be 60%, 62%, 65%, 67%, 70%, 72%, 75%, 78%, 80%, etc.

[0032] In a more preferred embodiment of the present application, the molar proportion of the non-silicon polymer diol in the diol raw material is 0-30%. Further preferably, the molar proportion of the non-silicon polymer diol in the diol raw material is 10-30%. For example, the molar ratio can be 10%, 15%, 20%, 25%, 30%, etc.

[0033] In a more preferred embodiment of the present application, the molar proportion of the diol chain extender in the diol raw material is 10-20%. In the present application, the diol chain extender can be selected from ethylene glycol, 1,4-butanediol, 1,6-hexanediol, etc. Specifically, the molar proportion of the diol chain extender in the diol raw material can be 10%, 12%, 14%, 15%, 16%, 18%, 20%, etc.

[0034] In a more preferred embodiment of the present application, the general formula of the dihydroxyalkyl polysiloxane is HOR 1 Me2SiO(SiOMe2) m (SiOMeR 2 ) n SiMe2R 1 OH, wherein, R 1 is selected from C2-C8 alkylene groups, R 2 is selected from C1-C18 hydrocarbon groups, C1-C18 substituted hydrocarbon groups or aromatic groups and their derivatives, Me represents a methyl group, m = 20-300, n = 3-20. For example, R 1 can be -CH2CH2CH2- or -CH2CH2CH2CH2-.

[0035] Further preferably, the said R 2 is selected from -OR 3 or -CH2CH2Me x Si(OR 4 ) 3-x , wherein R 3 and R 4 are independently selected from C1-C4 alkyl groups, x = 0-1, Me represents a methyl group. When R 2 is the above functional group, the alkoxy group has hydrolyzability and can be introduced into the structure of the compatibilizing agent, so that the side chain of the compatibilizing agent also contains hydrolyzable alkoxy groups. When the raw material components of the heat-insulating foamed shoe material are processed into premixed particles, the alkoxy group undergoes a hydrolysis and condensation reaction with the hydroxyl groups on the surface of the silica aerogel, which can further improve the compatibility between the ultrafine silica aerogel and TPU and the dispersion stability of the ultrafine silica aerogel in the heat-insulating foamed shoe material. When R2 is selected from -CH2CH2Me x Si(OR 4 ) 3-x , it can be obtained from the corresponding hydrogen-containing silicone oil and CH2=CHMe x Si(OR4 ) 3-x Obtained through hydrosilylation reaction.

[0036] In a preferred embodiment of the present application, the average particle size of the silica aerogel does not exceed 5 μm. More preferably, the average particle size of the silica aerogel is not less than 0.5 μm. If the average particle size of the silica aerogel is too low, it is not conducive to dispersion and the performance of heat insulation and heat preservation.

[0037] In a more preferred embodiment of the present application, the raw material components are pre-mixed to form pre-mixed particles. The mixing process can use a twin-screw extruder. After mixing the raw material components, they are added to the twin-screw extruder and melt-extruded and granulated at 220 - 230 °C.

[0038] The technical solutions of the present application will be described in detail below in combination with examples and comparative examples.

[0039] Preparation Examples 1 - 4 for preparing compatibilizing agents

[0040] Preparation Example 1

[0041] Bis-hydroxyalkyl polysiloxane HOCH2CH2CH2Me2SiO(SiOMe2) 68.3 SiMe2CH2CH2CH2OH;

[0042] Polytetrahydrofuran diol, average molecular weight 650;

[0043] The molar ratio of bis-hydroxyalkyl polysiloxane, polytetrahydrofuran diol, ethylene glycol and isophorone diisocyanate is 0.7:0.2:0.1:0.94.

[0044] After dehydrating and drying bis-hydroxyalkyl polysiloxane and polytetrahydrofuran diol, they are added to a reaction vessel, isophorone diisocyanate is added, and the reaction is carried out at 90 - 100 °C for 1 hour. 0.1% dibutyltin dilaurate based on the total weight of the reaction raw materials is added, and the reaction continues until the theoretical isocyanate content is reached. Then ethylene glycol is added, and the reaction continues for 3 hours. After cooling, it is obtained.

[0045] Preparation Example 2

[0046] In Preparation Example 1, the molar ratio of bis-hydroxyalkyl polysiloxane, polytetrahydrofuran diol, ethylene glycol and isophorone diisocyanate is adjusted to 0.65:0.2:0.15:0.97, and the remaining steps remain unchanged.

[0047] Preparation Example 3

[0048] Bis-hydroxyalkyl polysiloxane HOCH2CH2CH2Me2SiO(SiOMe2) 101.5 (SiOMeR 2 )7.4 SiMe2CH2CH2CH2OH, R 2 is -CH2CH2Si(OMe)3;

[0049] Polytetrahydrofuran diol, average molecular weight 650;

[0050] The molar ratio of the di - terminal hydroxyalkyl polysiloxane, polytetrahydrofuran diol, ethylene glycol and isophorone diisocyanate is 0.7:0.2:0.1:0.94.

[0051] After dehydrating and drying the di - terminal hydroxyalkyl polysiloxane and polytetrahydrofuran diol, they are added to a reaction vessel, isophorone diisocyanate is added, and the reaction is carried out at 90 - 100 °C for 1 hour. 0.1% dibutyltin dilaurate based on the total weight of the reaction raw materials is added, and the reaction is continued until the theoretical isocyanate content is reached. Then ethylene glycol is added, and the reaction is continued for 4 hours, followed by cooling to obtain the product.

[0052] Preparation Example 4

[0053] The molar ratio of the di - terminal hydroxyalkyl polysiloxane, polypropylene glycol (average molecular weight 1000), 1,4 - butanediol and hexamethylene diisocyanate in Preparation Example 3 is 0.8:0.1:0.1:0.98.

[0054] After dehydrating and drying the di - terminal hydroxyalkyl polysiloxane and polypropylene glycol, they are added to a reaction vessel, hexamethylene diisocyanate is added, and the reaction is carried out at 90 - 100 °C for 1 hour. 0.1% dibutyltin dilaurate based on the total weight of the reaction raw materials is added, and the reaction is continued until the theoretical isocyanate content is reached. Then 1,4 - butanediol is added, and the reaction is continued for 4 hours, followed by cooling to obtain the product.

[0055] Preparation Example 5

[0056] In Preparation Example 1, the molar ratio of the di - terminal hydroxyalkyl polysiloxane, polytetrahydrofuran diol, ethylene glycol and isophorone diisocyanate is adjusted to 0.5:0.4:0.1:0.94, and the remaining steps remain unchanged.

[0057] Example 1

[0058] The raw material components of the thermal insulation foaming material consist of 100 parts of TPU, 3 parts of ultrafine silica aerogel (average particle size 5 μm) and 1 part of the compatibility aid of Preparation Example 1.

[0059] Mix the above raw material components and add them to a twin-screw extruder. Heat and melt, extrude, and granulate at 210 - 230 °C to obtain pre-mixed granules; place the pre-mixed granules in an autoclave and seal it. Pass supercritical CO2 with a pressure of 22 MPa at 70 °C until the pre-mixed granules are saturated and maintain for 3 hours, then rapidly release the pressure to obtain a swollen part; take out the swollen part and place it in a constant-temperature device at 90 °C and maintain for 25 minutes to obtain heat-insulating and foamed shoe materials.

[0060] Example 2

[0061] In Example 1, the compatibilizing agent in Preparation Example 1 was adjusted to the compatibilizing agent of Preparation Example 2 in equal weight parts, and the remaining steps remained unchanged.

[0062] Example 3

[0063] In Example 1, the compatibilizing agent in Preparation Example 1 was adjusted to the compatibilizing agent of Preparation Example 3 in equal weight parts, and the remaining steps remained unchanged.

[0064] Example 4

[0065] In Example 1, the compatibilizing agent in Preparation Example 1 was adjusted to the compatibilizing agent of Preparation Example 4 in equal weight parts, and the remaining steps remained unchanged.

[0066] Example 5

[0067] In Example 1, the compatibilizing agent in Preparation Example 1 was adjusted to the compatibilizing agent of Preparation Example 54 in equal weight parts, and the remaining steps remained unchanged.

[0068] Example 6

[0069] The raw material components of the heat-insulating and foamed material consist of 100 parts of TPU, 1 part of ultrafine silica aerogel (average particle size 3 μm), and 0.3 parts of the compatibilizing agent of Preparation Example 3. Foam according to the supercritical foaming method of Example 1 to prepare heat-insulating and foamed shoe materials.

[0070] Example 7

[0071] In Example 6, the ultrafine silica aerogel was adjusted from 1 part to 3 parts, and the compatibilizing agent was adjusted from 0.3 parts to 1.2 parts, and the remaining steps remained unchanged.

[0072] Example 8

[0073] In Example 6, the ultrafine silica aerogel was adjusted from 1 part to 6 parts, and the compatibilizing agent was adjusted from 0.3 parts to 2.3 parts, and the remaining steps remained unchanged.

[0074] Example 9

[0075] In Example 6, the ultrafine silica aerogel was adjusted from 1 part to 10 parts, and the compatibilizing agent was adjusted from 0.3 part to 4.5 parts, while the remaining steps remained unchanged.

[0076] Comparative Example 1

[0077] In Example 1, the compatibilizing agent of Preparation Example 1 was not added, and the remaining steps remained unchanged.

[0078] Comparative Example 2

[0079] Terminal hydrogen polysiloxane HMe2SiO(SiOMe2) 69.2 SiMe2H and terminal allyl polyether CH2=CHCH2O(CH2CHCH3O) 12.5 CH3 were subjected to a hydrosilylation reaction in a molar ratio of 1:2.05 to prepare a polyether-polysiloxane-polyether copolymer.

[0080] In Example 1, the compatibilizing agent of Preparation Example 1 was replaced with the above polyether-polysiloxane-polyether copolymer in an equal weight portion, and the remaining steps remained unchanged.

[0081] Performance test Rebound resilience: The falling ball rebound method was used and tested according to the method of ASTM-D3574.

[0082] Thermal conductivity: Tested according to the method of ASTM-D5470.

[0083] Dispersion uniformity test: For the same shoe material, samples of the same size were taken from 5 parts in the middle, front and back, and left and right, and the rebound resilience was tested. The average value and standard deviation of the 5 data were taken.

[0084] The results are shown in Table 1 below.

[0085] Table 1

[0086]

[0087] It can be seen from the results in Table 1 that compared with directly adding ultrafine silica aerogel to TPU for supercritical foaming, the heat-insulating foamed shoe material of the present application has better rebound resilience and lower thermal conductivity. Moreover, from the standard deviation of the average rebound rate, it can be known that adding a compatibilizing agent in the present application can significantly improve the compatibility between TPU and ultrafine silica aerogel, and the dispersion of ultrafine silica aerogel in TPU is better.

[0088] This specific embodiment is only an explanation of the present application, and it is not a limitation of the present application. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A heat-insulating foamed shoe material containing silica aerogel, characterized in that, By weight parts, the raw material components include 100 parts of TPU, 1-10 parts of silica aerogel, and 0.2-5 parts of compatibilizing agent; The compatibilizing agent is a polysiloxane-modified linear-structured polyurethane; The heat-insulating foamed shoe material is prepared by a supercritical foaming technology; The compatibilizing agent is obtained by the reaction of a diol raw material and a diisocyanate; The diol raw material is composed of a double-ended hydroxyalkyl polysiloxane, a non-silicon polymer diol, and a diol chain extender.

2. The heat-insulating foamed shoe material according to claim 1, characterized in that, The molar ratio of the diol raw material to the diisocyanate is 1:0.9-1.

3. The heat-insulating foamed shoe material according to claim 1, characterized in that, The molar proportion of the double-ended hydroxyalkyl polysiloxane in the diol raw material is 60-90%.

4. The heat-insulating foamed shoe material according to claim 1, characterized in that, The molar proportion of the non-silicon polymer diol in the diol raw material is 0-30%.

5. The heat-insulating foamed shoe material according to claim 1, characterized in that, The molar proportion of the diol chain extender in the diol raw material is 10-20%.

6. The heat-insulating foamed shoe material according to claim 1, characterized in that, The general formula of the dihydroxyalkyl polysiloxane is HOR 1 Me2SiO(SiOMe2) m (SiOMeR 2 ) n SiMe2R 1 OH, where R 1 is selected from C2-C8 alkylene groups, and R 2 is selected from C1-C18 hydrocarbon groups, C1-C18 substituted hydrocarbon groups or aromatic groups, Me represents a methyl group, m = 20 - 300, and n = 3 - 20.

7. The heat-insulating foamed shoe material according to claim 6, characterized in that, Said R 2 is selected from -CH2CH2Me x Si(OR 4 ) 3-x , where R 4 is independently selected from C1-C4 alkyl, x = 0-1, and Me represents methyl.

8. The heat-insulating foamed shoe material according to claim 1, characterized in that, The average particle size of the silica aerogel does not exceed 5 μm.

9. The heat-insulating foamed shoe material according to claim 1, characterized in that, The raw material components are pre-mixed to form pre-mixed particles.

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