Sandal insole, preparation method thereof and sandal

Abstract

The invention discloses a sandal insole, a preparation method thereof and a sandal, and relates to the field of shoe materials. The sandal insole comprises a PU insole base material, and the PU insole base material is formed by reacting a material A and a material B; the material A comprises bifunctional polytetrahydrofuran ether, micromolecular straight-chain diol, branched-chain diol, a chemical foaming agent, a catalyst and polyether silicone oil; the branched chain diol is selected from at least one of 2-butyl-2-ethyl-1, 3-propylene glycol and 2, 2, 4-trimethyl-1, 3-pentanediol, and the branched chain diol is selected from at least one of 2-butyl-2-ethyl-1, 3-propylene glycol and 2, 2, 4-trimethyl-1, 3-pentanediol; the material B comprises an isocyanate component A and an isocyanate component B, the isocyanate component A is obtained by reaction of diphenylmethane diisocyanate, polypropylene oxide glycol, polypropylene oxide triol and carbodiimide modified diphenylmethane diisocyanate according to a specific ratio, and the isocyanate component B is isophorone diisocyanate. The sandal insole has the advantages of excellent seawater resistance, low compression set rate, good mechanical properties and long service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of shoe materials, in particular to a sandal insole and a preparation method thereof and a sandal. BACKGROUND

[0002] Sandal is often used for wading, beach and daily leisure wear. As a key component of sandal directly contacting with feet, the performance of insole directly affects the comfort and durability of the wearer. Among them, the ideal insole material should have good mechanical properties, low compression permanent deformation and hydrolysis resistance, especially the ability to resist corrosive media such as seawater and sweat.

[0003] At present, in the related technology, the common materials of sandal insole are EVA foaming material and PU foaming material. Compared with EVA foaming material, PU foaming material has the characteristics of lighter weight, but the disadvantage of PU foaming material is poor hydrolysis resistance, especially poor seawater resistance and short service life. SUMMARY

[0004] In order to improve the problem of poor seawater resistance of the sandal insole made of PU foaming material in the related technology, the present application provides a sandal insole and a preparation method thereof.

[0005] A sandal insole, comprising a PU insole substrate, the PU insole substrate is formed by reaction of A material and B material in a mold; The A material comprises 80-90 parts by weight of 2-functional polytetrahydrofuran ether, 10-15 parts by weight of small molecule linear diol, 15-20 parts by weight of branched diol, 1.5-2.0 parts by weight of chemical foaming agent, 1-2 parts by weight of catalyst and 0.4-0.5 parts by weight of polyether silicone oil; the branched diol uses at least one of 2-butyl-2-ethyl-1,3-propanediol and 2,2,4-trimethyl-1,3-pentanediol; The B material comprises 90-105 parts by weight of isocyanate component A and 30-35 parts by weight of isocyanate component B, the isocyanate component A is obtained by reaction of diphenylmethane diisocyanate, polyoxypropylene diol, polyoxypropylene triol and carbodiimide modified diphenylmethane diisocyanate in a weight ratio of (30-40):(6-8):(12-14):(25-30), and the isocyanate component B is isophorone diisocyanate.

[0006] The present application uses 2-functional polytetrahydrofuran ether as the main soft segment to improve the high elasticity and hydrolysis resistance of the PU insole substrate. At the same time, by introducing specific proportions of small molecule linear diols, specific branched diols (such as at least one of 2-butyl-2-ethyl-1,3-propanediol and 2,2,4-trimethyl-1,3-pentanediol) and polyether silicone oil into the PU insole substrate, the hardness of the PU insole substrate can be increased to provide support for the foot, and the deformation resistance and hydrolysis resistance of the PU insole substrate can be further improved, especially the performance of resisting seawater. In addition, in the present application, the B material is composed of a composition of specific proportions of isocyanate component A and isocyanate component B, the isocyanate component A is obtained by reacting diphenylmethane diisocyanate, polyoxypropylene diol, polyoxypropylene triol and carbodiimide modified diphenylmethane diisocyanate in a specific proportion, and the isocyanate component B uses isophorone diisocyanate. The B material can be uniformly dispersed in the A material system, and the reaction speed with the A material is relatively moderate. With the cooperation of the polyether silicone oil foam stabilizing effect, the hydroxyl component in the A material can react with the B material to form a PU insole substrate with uniform micropores and excellent resilience, which not only reduces the weight of the PU insole substrate, but also reduces the compression permanent deformation of the PU insole substrate, and effectively improves the seawater resistance of the PU insole substrate.

[0007] However, it should be noted that the ratio of isocyanate component A to isocyanate component B in the present application is controlled within the scope of the present application. On the basis of improving the seawater resistance of the PU insole substrate, while taking into account the low compression permanent deformation and excellent mechanical properties, exceeding this range is not conducive to taking into account the seawater resistance.

[0008] In some specific embodiments, the number average molecular weight of the 2-functional polytetrahydrofuran ether is in the range of 1800-2500 g / mol.

[0009] In some specific embodiments, the number average molecular weight of the polyoxypropylene diol is 4000-4500 g / mol, and the number average molecular weight of the polyoxypropylene triol is 4500-5000 g / mol.

[0010] In some specific embodiments, the small molecule linear diol uses at least one of ethanol, 1,3-propanediol and 1,4-butanediol.

[0011] In the present application, the small molecule linear diol as the hard segment of the PU insole substrate can increase the hardness of the PU insole substrate to provide support for the foot.

[0012] In some specific embodiments, the chemical foaming agent is water.

[0013] In the present application, water is selected as the chemical foaming agent, and carbon dioxide gas is released when water reacts with the isocyanate component A and the isocyanate component B, thereby providing a basis for the generation of the micro-pores in the sandal insole.

[0014] In some specific embodiments, the catalyst is a tertiary amine catalyst, such as at least one of triethylenediamine, bis(dimethylaminoethyl) ether, and dimethylcyclohexylamine.

[0015] In some specific embodiments, the sandal insole further comprises a TPU protective film covering the surface of the PU insole substrate.

[0016] The micro-pores on the surface of the PU insole substrate are prone to dirt accumulation, which causes the sandal insole to have mold-like stains. Therefore, the present application adds a layer of TPU protective film on the surface of the insole substrate. Under the blockage of the TPU protective film, dirt is not easy to enter the micro-pores of the PU insole substrate, and the dirt on the TPU protective film is also easy to be removed. Meanwhile, the TPU protective film can also protect the PU insole substrate from seawater erosion, which is conducive to further prolonging the service life of the sandal insole.

[0017] In some specific embodiments, the TPU protective film is waterproof and has a yellowing resistance index of 4 or above.

[0018] The waterproof TPU protective film can protect the PU insole substrate from seawater erosion and also prevent the PU insole substrate from being hydrolyzed. The TPU protective film has a yellowing resistance index of 4 or above, and the sandal insole is less likely to have yellowing problems.

[0019] In some specific embodiments, the surface of the TPU protective film is provided with anti-slip lines.

[0020] Providing anti-slip lines on the surface of the TPU protective film can improve the problem of slipping of the sandal insole.

[0021] A preparation method of a sandal insole, comprising the following steps: The components in the A material and the components in the B material are weighed according to the proportions; The 2-functional polytetrahydrofuran ether is melted, and then small-molecule linear diols, branched diols, a chemical foaming agent, a catalyst, and a polyether silicone oil are added and stirred uniformly to obtain the A material; The isocyanate component A and the isocyanate component B are added to the A material and stirred uniformly to obtain an intermediate material; The intermediate material is injected into a lower mold with a temperature of 50-60℃, and the reaction is initiated for 35-50s. After the material is milky white for 110-130s, the upper mold is combined with the lower mold containing the intermediate material, and the reaction is shaped for 30-45min. Then, the reaction-molded material blank is taken out and cut to obtain the sandal insole.

[0022] The above process of the application is beneficial to uniform mixing of the raw materials, so that the raw materials can fully react, thereby improving the quality stability of the PU insole substrate.

[0023] In some preferred embodiments, in the S4 step, the intermediate material is injected into the lower mold at a temperature of 50-60℃, and the mold is closed after 35-50s of rising and 110-130s of milky white, the upper mold with a TPU protective film covering the inner top surface is combined with the lower mold containing the intermediate material, and the reaction is shaped for 30-45min, then the reaction molded material blank is taken out and cut to obtain the sandal insole.

[0024] In some embodiments, the preparation of the isocyanate component A is also included, and the preparation steps of the isocyanate component A are as follows: After the diphenylmethane diisocyanate is baked and melted, the melted diphenylmethane diisocyanate is then pumped into the reaction kettle with the temperature controlled below 50℃, then the polyoxypropylene diol and polyoxypropylene triol with a temperature of 35-45℃ are pumped into the reaction kettle, heated to 60-70℃, and stirred to react, after the NCO content is detected to be 15-20%, the carbodiimide modified diphenylmethane diisocyanate is added, and the stirring is continued, and the NCO content is detected to be 20-25%, thereby obtaining the isocyanate component A.

[0025] The isocyanate component A prepared by the above method is a liquid, which is convenient to add, and at the same time, the isocyanate component A can be uniformly dispersed in the A material system, and the reaction speed with the A material is relatively moderate, which is beneficial to the PU insole substrate to form a uniform microporous structure. At the same time, the polyoxypropylene diol and polyoxypropylene triol are added, which is beneficial to the flexibility and support, improves the comfort while reducing the compression set of the PU insole substrate.

[0026] In summary, the application at least includes the following beneficial technical effects: (1) This application uses difunctional polytetrahydrofuran ether as the main soft segment, which can improve the high elasticity and hydrolysis resistance of the PU insole substrate. At the same time, introducing a specific ratio of small molecule straight-chain diols, specific branched diols (such as at least one of 2-butyl-2-ethyl-1,3-propanediol and 2,2,4-trimethyl-1,3-pentanediol) and polyether silicone oil into the PU insole substrate can increase the hardness of the PU insole substrate, provide support for the foot, and further improve the deformation resistance and hydrolysis resistance of the PU insole substrate, especially its seawater resistance. Furthermore, in this application, component B is a composition of isocyanate component A and isocyanate component B. Isocyanate component A is obtained by reacting diphenylmethane diisocyanate, polypropylene glycol, polypropylene triol, and carbodiimide-modified diphenylmethane diisocyanate in a specific ratio. Isocyanate component B is isophorone diisocyanate. Component B can be uniformly dispersed in the component A system, and its reaction rate with component A is relatively mild. With the foam stabilizing effect of polyether silicone oil, the hydroxyl component in component A of this application can react with component B to form a PU insole substrate with uniform micropores and excellent resilience. This reduces the weight of the PU insole substrate, reduces the compression set of the PU insole substrate, and improves the seawater resistance of the PU insole substrate.

[0027] (2) The tiny pores on the surface of the PU insole substrate are prone to trapping dirt and grime, causing mold-like stains to appear on the insole of sandals. To address this, this application adds a protective film to the surface of the insole substrate. Under the protection of the protective film, dirt is not easily able to enter the micropores of the PU insole substrate, and the dirt on the protective film is also easy to remove. At the same time, the protective film can also protect the PU insole substrate from seawater corrosion, which is beneficial to further extend the service life of the sandal insole. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the front of the sandal insole before cutting in Embodiment 4 of this application.

[0029] Figure 2 This is a schematic diagram of the back structure of the sandal insole before cutting in Embodiment 4 of this application.

[0030] Explanation of reference numerals in the attached figures: 1. PU inner bottom substrate; 2. TPU protective film. Detailed Implementation

[0031] The following section provides further explanation of this application in conjunction with specific experiments.

[0032] Preparation Example

Preparation Example 1

[0033]

Example 1

[0034] In this embodiment, the method for preparing the sandal insole includes the following steps: S1. Weigh out each component of material A and each component of material B according to the proportions. S2. After melting the difunctional polytetrahydrofuran ether, add ethylene glycol, 2-butyl-2-ethyl-1,3-propanediol, water, triethylenediamine and polyether silicone oil, and stir evenly to obtain material A; S3. Add isocyanate component A and isocyanate component B to material A, stir evenly, and obtain intermediate material; S4. Inject the intermediate material into the lower mold at a temperature of 50℃. After fermentation for 50 seconds and milky whitening for 130 seconds, close the upper mold with the lower mold containing the intermediate material. Allow the material to react and solidify for 45 minutes. Then, open the mold and remove the reacted and shaped blank, and cut it to obtain the inner sole of the sandal.

[0035]

Example 2

[0036] In this embodiment, the method for preparing the sandal insole includes the following steps: In this embodiment, the method for preparing the sandal insole includes the following steps: S1. Weigh out each component of material A and each component of material B according to the proportions. S2. After melting the difunctional polytetrahydrofuran ether, add 1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, water, triethylenediamine and polyether silicone oil, and stir evenly to obtain material A; S3. Add isocyanate component A and isocyanate component B to material A, stir evenly, and obtain intermediate material; S4. Inject the intermediate material into the lower mold at a temperature of 55℃. After fermentation for 42 seconds and milky whitening for 120 seconds, close the upper mold with the lower mold containing the intermediate material. Let it react and solidify for 40 minutes. Then open the mold and take out the reacted and shaped blank, and cut it to obtain the sandal insole.

[0037]

Example 3

[0038] In this embodiment, the method for preparing the sandal insole includes the following steps: S1. Weigh out each component of material A and each component of material B according to the proportions. S2. After melting the difunctional polytetrahydrofuran ether, add 1,4-butanediol, 2-butyl-2-ethyl-1,3-propanediol, water, triethylenediamine and polyether silicone oil, and stir evenly to obtain material A. S3. Add isocyanate component A and isocyanate component B to material A, stir evenly, and obtain intermediate material; S4. Inject the intermediate material into the lower mold at a temperature of 60℃. After fermentation for 35 seconds and milky whitening for 110 seconds, close the upper mold with the lower mold containing the intermediate material. Let it react and solidify for 30 minutes. Then open the mold and take out the reacted and shaped blank, and cut it to obtain the sandal insole.

[0039]

Example 4

[0040] In this embodiment, the preparation method of the sandal insole differs from that in [Example 1] in that: S4. Inject the intermediate material into the lower mold at a temperature of 50℃. After fermentation for 50 seconds and milky whitening for 130 seconds, close the upper mold with the TPU protective film covering the inner top surface and the lower mold containing the intermediate material. Let it react and solidify for 45 minutes. Then open the mold and take out the reacted and shaped blank, and cut it to obtain the sandal insole.

[0041] Comparative Example Comparative Example 1 A sandal insole differs from that in [Example 1] in that: in this comparative example, 2-butyl-2-ethyl-1,3-propanediol is replaced by an equimolar amount of 2-methyl-1,3-propanediol.

[0042] Comparative Example 2 A sandal insole differs from that in [Example 1] in that: in this comparative example, 2-butyl-2-ethyl-1,3-propanediol is replaced by an equimolar amount of ethylene glycol.

[0043] Comparative Example 3 A sandal insole differs from that in [Example 1] in that: in this comparative example, ethylene glycol is replaced by an equimolar amount of 2-butyl-2-ethyl-1,3-propanediol.

[0044] Comparative Example 4 A sandal insole differs from that in [Example 1] in that: no polyether silicone oil was added in this comparative example.

[0045] Comparative Example 5 A sandal insole differs from [Example 1] in that: in this comparative example, isocyanate component B is used instead of isocyanate component A, while ensuring that the molar content of isocyanate in material B remains unchanged.

[0046] Comparative Example 6 A sandal insole differs from [Example 1] in that: in this comparative example, isocyanate component A is used instead of isocyanate component B, while ensuring that the molar content of isocyanate in material B remains unchanged.

[0047] Performance testing (1) Compression permanent deformation rate: The compression permanent deformation rate of the sandal insole in each embodiment and comparative example under normal temperature conditions was tested according to GB / T 43549-2023, and the results are recorded in Table 1 below.

[0048] (2) Tear strength: The longitudinal tear strength of the sandal insoles obtained in each embodiment and comparative example was tested according to HG / T 2726-1995, and the results are recorded in Table 1 below.

[0049] (3) Elongation at break: The elongation at break of the sandal insole obtained in each embodiment and comparative example was tested according to GB / T 528-2009, and the results are recorded in Table 1 below.

[0050] (4) Seawater resistance: The sandal insoles prepared in each embodiment were immersed in artificial seawater formula (sodium chloride aqueous solution with a mass concentration of 27%) at a temperature of 80°C for 5 days. They were then taken out, washed and dried, and then tested for compression set, tear strength and elongation according to tests (1), (2) and (3).

[0051] Table 1

[0052] The difference between Comparative Example 1 and Example 1 is that 2-butyl-2-ethyl-1,3-propanediol is replaced by an equimolar amount of 2-methyl-1,3-propanediol. 2-methyl-1,3-propanediol and 2-butyl-2-ethyl-1,3-propanediol are structurally different branched diols. Based on the test data in Table 1, it can be seen that in the PU insole substrate of this application, only when 2-methyl-1,3-propanediol is used as the branched diol can the seawater hydrolysis resistance of the PU insole substrate be significantly reduced. That is, introducing any branched diol cannot significantly improve the seawater resistance of the PU insole substrate in this application.

[0053] The difference between Comparative Example 2 and Example 1 is that 2-butyl-2-ethyl-1,3-propanediol is replaced with an equimolar amount of ethylene glycol. According to the test data in Table 1, in the PU insole substrate of this application, although the tear strength of the PU insole substrate is increased by using ethylene glycol alone for chain extension, the compression set of the PU insole substrate is increased, and the seawater hydrolysis resistance and elongation are significantly reduced.

[0054] The difference between Comparative Example 3 and Example 1 is that ethylene glycol is replaced with an equimolar amount of 2-butyl-2-ethyl-1,3-propanediol. According to the test data in Table 1, in the PU insole substrate of this application, chain extension with 2-butyl-2-ethyl-1,3-propanediol alone increases the elongation of the PU insole substrate; however, it also increases the compression set and significantly reduces the tear strength and seawater hydrolysis resistance.

[0055] The difference between Comparative Example 4 and Example 1 is that no polyether silicone oil was added. According to the test data in Table 1, without the addition of polyether silicone oil, the PU insole substrate of this application cannot form a uniformly distributed microporous structure, resulting in decreased mechanical properties. Simultaneously, the seawater hydrolysis resistance of the PU insole substrate is also significantly reduced.

[0056] The difference between Comparative Example 5 and Example 1 is that isocyanate component B (i.e., isophorone diisocyanate) is used alone as component B. According to the test data in Table 1, when isophorone diisocyanate is used alone as component B, the mechanical properties of the PU insole substrate decrease, and the seawater hydrolysis resistance of the PU insole substrate is also significantly reduced.

[0057] The difference between Comparative Example 6 and Example 1 is that when isocyanate component A is used alone as component B, the seawater hydrolysis resistance of the PU insole substrate is significantly reduced when isocyanate component A is used alone as component B.

[0058] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A sandal insole, characterized in that: Includes a PU insole substrate, which is formed by reacting material A and material B in a mold; Material A comprises 80-90 parts by weight of difunctional polytetrahydrofuran ether, 10-15 parts by weight of small molecule straight-chain diol, 15-20 parts by weight of branched-chain diol, 1.5-2.0 parts by weight of chemical foaming agent, 1-2 parts by weight of catalyst, and 0.4-0.5 parts by weight of polyether silicone oil; the branched-chain diol is at least one selected from 2-butyl-2-ethyl-1,3-propanediol and 2,2,4-trimethyl-1,3-pentanediol. The B component comprises 90-105 parts by weight of isocyanate component A and 30-35 parts by weight of isocyanate component B. The isocyanate component A is obtained by reacting diphenylmethane diisocyanate, polypropylene glycol, polypropylene triol, and carbodiimide-modified diphenylmethane diisocyanate in a weight ratio of (30-40):(6-8):(12-14):(25-30). The isocyanate component B is isophorone diisocyanate.

2. The sandal insole according to claim 1, characterized in that: The number-average molecular weight range of the difunctional polytetrahydrofuran ether is 1800-2500 g / mol.

3. The sandal insole according to claim 1, characterized in that: The number-average molecular weight of the polypropylene glycol is 4000-4500 g / mol, and the number-average molecular weight of the polypropylene triol is 4500-5000 g / mol.

4. The sandal insole according to claim 1, characterized in that: The small molecule straight-chain diol is at least one of ethanol, 1,3-propanediol, and 1,4-butanediol.

5. The sandal insole according to claim 1, characterized in that: The chemical foaming agent is water; the catalyst is a tertiary amine catalyst.

6. A sandal insole according to any one of claims 1-5, characterized in that: The sandal insole also includes a TPU protective film covering the surface of the PU insole substrate.

7. The sandal insole according to claim 6, characterized in that: The TPU protective film has a yellowing resistance index of 4 or higher.

8. A method for preparing a sandal insole as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Weigh out each component of material A and each component of material B according to the proportions. S2. After melting the difunctional polytetrahydrofuran ether, add small molecule straight-chain diol, branched diol, chemical foaming agent, catalyst and polyether silicone oil, stir evenly to obtain material A. S3. Add isocyanate component A and isocyanate component B to material A, stir evenly, and obtain intermediate material; S4. Inject the intermediate material into the lower mold to start fermentation. After it turns milky white, close the upper mold with the lower mold containing the intermediate material to react and solidify. Then, take out the reacted and shaped blank and cut it to obtain the sandal insole.

9. The method for preparing a sandal insole according to claim 8, characterized in that: In step S4, the intermediate material is injected into the lower mold to start fermentation. After it turns milky white, the upper mold with a TPU protective film covering the inner top surface is closed with the lower mold containing the intermediate material. The reaction is solidified, and then the reacted and shaped blank is taken out and cut to obtain the sandal insole.

10. A method for preparing a sandal insole according to claim 8 or 9, characterized in that: The starting temperature is 50-60℃, and the milky white time is 110-130s.

11. A method for preparing a sandal insole according to claim 8, characterized in that: It also includes the preparation of isocyanate component A, the preparation steps of which are as follows: After melting diphenylmethane diisocyanate by baking, the temperature was controlled below 50°C and the melted diphenylmethane diisocyanate was pumped into a reaction vessel. Then, polypropylene glycol and polypropylene triol at a temperature of 35°C-45°C were pumped into the reaction vessel and heated to react. After the NCO content reached 15-20%, carbodiimide-modified diphenylmethane diisocyanate was added and stirring was continued. When the NCO content reached 20-25%, isocyanate component A was obtained.

12. A sandal, characterized in that: Includes the sandal insole as described in any one of claims 1-7.

Images