Composite materials for insoles

Abstract

The present invention relates to a composite material for insoles, which contains aerogel particles and polyurethane, which is a reaction product of a polyether polyol and an isocyanate compound. The aerogel particles provide a composite material for insoles with low thermal conductivity, which effectively blocks external temperatures, and excellent thermal insulation.

Description

[Technical Field]

[0001] [1] The present invention relates to a composite material for an insole. [Background technology]

[0002] [2] In recent years, as interest in health has grown, there has been an increasing demand for functional shoes that make feet more comfortable.

[0003] [3] Functional shoes are very expensive due to their unique characteristics, so they can only be used in very limited situations. As they are consumer goods, they incur costs periodically, so there is an increasing demand for functional insoles that can be used for all shoes.

[0004] [4] However, conventional functional insoles, even if they have insulating properties, lack elasticity and lightness, making it difficult to protect the feet of the shoe wearer, while insoles with excellent elasticity and hardness have poor insulating properties and are therefore difficult to keep the feet of the shoe wearer warm. Summary of the Invention

[0005] [5] In this embodiment, an attempt is made to provide a composite material for insoles that has excellent hardness and elasticity, as well as light weight, breathability, and heat insulation.

[0006] [6] An insole composite material according to one embodiment may include polyurethane, which is a reaction product of a polyether polyol and an isocyanate compound, and aerogel particles.

[0007] [7] The polyether polyol may have a hydroxyl value in the range of 20 to 40 mgKOH / g.

[0008] [8] The polyether polyol may have a weight average molecular weight in the range of 3,000 to 7,500.

[0009] [9] The polyether polyol may have a viscosity at 25°C in the range of 1,000 to 4,500 mPa·s and a density at 20°C in the range of 1.0 to 1.1 g / cm 3 may be in the range of

[0010]

[10] The aerogel particles may have an average particle size of 50 μm or less, and an average pore size in the range of 5 nm to 20 nm.

[0011]

[11] The apparent density of aerogel particles is 0.03–0.1 g / cm 3 The aerogel particles may have hydrophobic functional groups on their surfaces.

[0012]

[12] The specific surface area (BET) of aerogel particles is 600-800 m 2 / kg, and the thermal conductivity of the aerogel particles may be 0.022 W / mK or less.

[0013]

[13] The isocyanate compound may contain hydroxyl groups (OH) in the range of 2.5 / mol to 3.0 / mol.

[0014]

[14] Based on the isocyanate compound, the content of isocyanate groups (NCO) may be in the range of 30% by weight to 33% by weight.

[0015]

[15] The isocyanate compound may have a viscosity at 20°C in the range of 250 to 270 mPa·s, or a viscosity at 25°C in the range of 210 to 230 mPa·s.

[0016]

[16] Also, isocyanate compounds have a density of 1.2 to 1.25 g / cm at 25°C. 3 may be in the range of

[0017]

[17] The composite material for an insole of this embodiment may contain 95% by weight to 99% by weight of polyurethane and 1% by weight to 5% by weight of aerogel particles, based on 100 parts by weight of the composite material for an insole.

[0018]

[18] The polyurethane may contain an isocyanate compound in the range of 100 to 110 parts by weight based on 100 parts by weight of the polyether polyol.

[0019]

[19] The composite material for an insole may have an Asker C hardness in the range of 25 to 35, an Asker F hardness in the range of 70 to 95, and a density of 0.08 to 0.13 g / cm as measured by ASTM D792. 3 may be in the range of

[0020]

[20] The composite material for an insole may have a thermal conductivity in the range of 20 to 40 mW / mK. [twenty one]

[0021]

[22] In this example, a composite material for insoles with excellent thermal insulation properties can be provided, as it contains aerogel particles and has low thermal conductivity that can effectively block external temperatures.

[0022]

[23] In addition, the composite material for insoles according to this embodiment has the strength and elasticity for shock absorption, and is also excellent in breathability and lightness, so that the thickness of the insole can be controlled as desired and it can be applied to various functional shoes. [Brief explanation of the drawings]

[0023] [Figure 1]

[24] Results of heat resistance tests performed at 2 psi on the insoles manufactured according to Comparative Example 1. [Figure 2]

[25] Results of heat resistance tests measured at 2 psi for insoles made according to Example 1. [Figure 3]

[26] Heat resistance test results measured at 2 psi for insoles made according to Example 2. [Figure 4]

[27] Results of heat resistance tests measured at 2 psi for insoles made according to Example 3. [Figure 5]

[28] Results of heat resistance tests performed at 10 psi on the insoles manufactured according to Comparative Example 1. [Figure 6]

[29] Results of heat resistance tests measured at 10 psi for insoles made according to Example 1. [Figure 7]

[30] Results of heat resistance tests measured at 10 psi for insoles made according to Example 2. [Figure 8]

[31] Heat resistance test results measured at 10 psi for the insole produced according to Example 3.

[32] DETAILED DESCRIPTION OF THE INVENTION

[0024]

[33] Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited to these. These terms are used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Therefore, a first part, component, region, layer, or section described below can be replaced with a second part, component, region, layer, or section without departing from the scope of the present invention.

[0025]

[34] The terminology used herein is merely for the purpose of referring to particular embodiments and is not intended to limit the invention. As used herein, the singular includes the plural unless the phrase clearly indicates otherwise. As used in the specification, the meaning of "comprising" embodies certain properties, regions, integers, steps, operations, elements, and / or components, and does not exclude the presence or addition of other properties, regions, integers, steps, operations, elements, and / or components.

[0026]

[35] When a part is referred to as being "on" or "above" another part, this means that it is directly on or above the other part, or there may be other parts between them. In contrast, when a part is referred to as being "directly above" another part, there are no other parts between them.

[0027]

[36] Unless otherwise specified, % means % by weight, and 1 ppm is 0.0001% by weight.

[0028]

[37] Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries are additionally construed to have a meaning consistent with the relevant technical literature and the presently disclosed content, and are not construed as having an ideal or very formal meaning unless otherwise defined.

[38]

[0029]

[39] An insole composite material according to one embodiment includes a polyurethane, which is a reaction product of a polyether polyol and an isocyanate compound, and aerogel particles.

[0030]

[40] When polyether polyols are used in composite materials for insoles, they have the advantageous effect of producing insoles that have excellent flexural strength and elasticity at low temperatures while also being hydrolysis resistant. Such polyether polyols may have a hydroxyl value in the range of 20 to 40 mgKOH / g. When the hydroxyl value of the polyether polyol falls within this range, the reactivity of the polyol with isocyanate groups and the strength of the resulting polyurethane are excellent.

[0031]

[41] The polyether polyol may have a weight-average molecular weight in the range of 3,000 to 7,500. When the weight-average molecular weight of the polyether polyol satisfies this range, a balance is achieved between the processing conditions (e.g., viscosity) required to ensure comfort for the shoe wearer and the properties (e.g., flexibility, hardness, elasticity) of the resulting insole. In other words, the polyether polyol has excellent reactivity and appropriate viscosity, resulting in the polyurethane, which is the reaction product, having excellent elasticity and hardness.

[0032]

[42] The polyether polyol may have a viscosity at 25°C in the range of 1,000 to 4,500 mPa·s.

[0033]

[43] Polyether polyols have a density of 1.0 to 1.1 g / cm at 20°C. 3 When the viscosity and density of the polyether polyol are within this range, more aerogel particles can be added, and at the same time, a polyurethane foam having low density characteristics can be realized.

[0034]

[44] In this embodiment, the average particle size of the aerogel particles may be 50 μm or less, more specifically, in the range of 1 μm to 45 μm. When the aerogel particles are contained in the composite material for an insole according to one embodiment, the heat insulating performance at low temperatures (e.g., −78°C) can be significantly improved.

[0035]

[45] The average pore size of the aerogel particles may be in the range of 5 nm to 20 nm, more specifically in the range of 9 nm to 11 nm.

[0036]

[46] When the average particle size and pore size of aerogel particles are within these ranges, they are easily dispersed and bound in polyether polyol, the polyol-aerogel particle mixture has an appropriate viscosity, and the amount of aerogel particles added to the polyol can be increased, further improving the thermal insulation performance of the insole composite.

[0037]

[47] On the other hand, the apparent density of aerogel particles is 0.03–0.1 g / cm 3 range, more specifically 0.03 to 0.06 g / cm 3The apparent density of the aerogel particles may be in the range of 0.01 to 0.01. When the apparent density of the aerogel particles is within this range, high thermal insulation performance and volume compared to the added weight can be ensured when mixed with polyol. On the other hand, if the density is too high, more must be added to achieve the same performance, which may increase the weight of the final product (insole). Conversely, if the density is too low, the viscosity will increase rapidly when mixed with polyol, which will limit the amount of aerogel that can be added.

[0038]

[48] ​​In this embodiment, the surface of the aerogel particles may have hydrophobic functional groups, more specifically, superhydrophobic functional groups. The presence of hydrophobic functional groups on the surface of the aerogel particles is advantageous in reducing the moisture absorption effect of the insole and maintaining its original state. When a non-hydrophobic porous filler is used, moisture such as sweat is more easily absorbed and its release is delayed. This is not an advantageous effect for the insole.

[0039]

[49] The specific surface area (BET) of aerogel particles is 600–800 m 2 / kg range, more specifically 700-800m 2 / kg. When the specific surface area of ​​the aerogel particles is within this range, higher insulation performance can be expected compared to the same content. In the case of porous insulation materials such as aerogel, the higher the specific surface area, the better the insulation performance, so using aerogel with as high a specific surface area as possible is a way to improve product performance.

[0040]

[50] The thermal conductivity of the aerogel particles may be 0.022 W / mK or less, more specifically, in the range of 0.016 to 0.020. When the thermal conductivity of the aerogel particles satisfies this range, an insole with excellent thermal insulation performance can be produced.

[0041]

[51] On the other hand, the isocyanate compound may contain hydroxyl groups (OH) in the range of 2.5 / mol to 3.0 / mol. When the isocyanate compound contains hydroxyl groups in this range, the produced polyurethane foam has sufficient crosslinking properties and can ensure higher strength.

[0042]

[52] The isocyanate group (NCO) content may be in the range of 30% by weight to 33% by weight based on the isocyanate compound. When the isocyanate group content is in this range, excellent reactivity with polyols having higher equivalent weights is exhibited.

[0043]

[53] The isocyanate compound may have a viscosity at 20°C in the range of 250 to 270 mPa·s. The isocyanate compound may have a viscosity at 25°C in the range of 210 to 230 mPa·s. When the viscosities at 20°C and 25°C of the isocyanate compound are within this range, it can be appropriately mixed with other components such as polyols and aerogels.

[0044]

[54] Isocyanate compounds have a density of 1.2 to 1.25 g / cm at 25°C. 3 may be in the range of

[0045]

[55] The composite material for an insole of this embodiment may contain 95% by weight to 99% by weight of polyurethane and 1% by weight to 5% by weight of aerogel particles, based on 100 parts by weight of the composite material for an insole.

[0046]

[56] The polyurethane may contain 100 to 110 parts by weight of an isocyanate compound based on 100 parts by weight of a polyether polyol. When the mixing ratio of the isocyanate compound to the polyether polyol satisfies this range, an appropriate amount of a reactive blowing agent may be added depending on the NCO number and OH number.

[0047]

[57] The composite material for an insole of this example may have an Asker C hardness in the range of 25 to 35.

[0048]

[58] The composite material for an insole may have an Asker F hardness in the range of 70 to 95.

[0049]

[59] The composite material for the insole has a density of 0.08 to 0.13 g / cm3 as measured by ASTM D792. 3 The composite material for an insole may have a thermal conductivity in the range of 20 to 45 mW / mK.

[60]

[0050]

[61] The shoe insole of this embodiment may include, for example, a first cushioning layer, a second cushioning layer, and a plantar contact layer, where the first cushioning layer is made of the composite insole material of the embodiment, a second cushioning layer made of polyurethane and attached on the first cushioning layer, and a plantar contact layer attached on the second cushioning material and in contact with the sole of the user's foot.

[0051]

[62] An adhesive layer may be located between the first cushioning layer, the second cushioning layer, and the plantar contact layer.

[0052]

[63] When the insole composite material of this embodiment is used to manufacture a first cushioning layer, it can ensure appropriate elasticity and hardness while providing excellent heat insulation performance. It is also lightweight and breathable, so that the thickness can be adjusted as desired and the insole composite material can be used in functional shoes for various purposes.

[64]

[0053]

[65] The following detailed description of the present invention is provided by way of example only and does not limit the scope of the present invention, which is defined solely by the scope of the claims set forth below.

[66]

[0054]

[67] Example 1

[68] (1) Manufacturing of composite materials for insoles

[69] 98g of polyether polyol and 6g of silica aerogel powder were mixed and stirred to prepare a mixture. 100g of MDI was added to 104g of the mixture, stirred, and then poured into a container and foamed to produce a composite material for insoles. Foaming was completed within approximately 5 minutes at room temperature.

[0055]

[70] The density of the produced composite material was 0.09 g / cm 3 The hardness was 34 (asker C) and the thermal conductivity was 36 mW / mK.

[0056]

[71] (2) Manufacturing of insoles

[72] The first cushion layer was manufactured using the composite material prepared in (1).

[0057]

[73] Next, a second cushioning layer was manufactured using polyurethane foam and then adhered onto the first cushioning layer with an adhesive.

[0058]

[74] After this, a plantar contact layer was made using nonwoven fabric, and then adhered onto the second cushion layer with an adhesive to produce an insole sample.

[0059]

[75] At this time, the thickness of the first cushion layer was 2.0 mm and the thickness of the second cushion layer was 3.5 mm.

[76]

[0060]

[77] Example 2

[78] A composite material for an insole was produced in the same manner as in Example 1, except that the thickness of the first cushioning layer was 3.5 mm and the thickness of the second cushioning layer was 2.0 mm, and then an insole was produced.

[79]

[0061]

[80] Example 3

[81] A composite material for an insole was produced in the same manner as in Example 1(1), and then a first cushioning layer was produced using the composite material. Next, a plantar contact layer was bonded to the first cushioning layer with an adhesive to produce an insole. At this time, the thickness of the first cushioning layer was 5.5 mm.

[82]

[0062]

[83] Comparative Example 1

[84] In Example 1 (2), the first cushioning layer was not used, and a second cushioning layer was produced with a thickness of 5.5 mm, and then only the plantar contact layer was adhered to this to produce an insole.

[85]

[0063]

[86] Experimental Example 1

[87] The heat resistance of the insoles manufactured in Examples 1 to 3 and Comparative Example 1 was measured.

[0064]

[88] Specifically, heat resistance was measured using Instron's heat resistance measurement equipment. Specifically, dry ice at approximately -78°C was placed on the measurement table, and the sample was placed on the dry ice. After that, the temperature was measured using a thermocouple that monitors heat transfer while applying pressure as shown in Table 1 below using a pressure member. The results are shown in Table 1 below and Figures 1 to 8.

[0065] [Table 1]

[0066]

[90] Referring to Table 1, it can be seen that the insoles manufactured in Examples 1 to 3 are lighter in weight than Comparative Example 1, despite further including a first cushion layer. In other words, they are superior in lightness. It can also be seen that Examples 1 to 3 have low thermal conductivity and high Asker hardness C.

[0067]

[91] Next, the results for Comparative Example 1 measured at 2 psi are shown in Figure 1, the results for Examples 1 to 3 are shown in Figures 2 to 4, the results for Comparative Example 1 measured at 10 psi are shown in Figure 5, and the results for Examples 1 to 3 are shown in Figures 6 to 8.

[0068]

[92] Referring to Figures 1 and 5, it can be seen that the insole sample manufactured according to Comparative Example 1 has a large difference between the ambient temperature and the sample temperature at pressures of 2 psi and 10 psi, respectively.

[0069]

[93] In contrast, referring to Figures 2 to 4 and Figures 6 to 8, it can be seen that the insole samples manufactured according to Examples 1 to 3 have relatively smaller differences between the ambient temperature and the sample temperature at pressures of 2 psi and 10 psi, respectively, compared to Comparative Example 1.

[0070]

[94] Referring to FIG. 8, in the case of Example 3, at a pressure of 10 psi, the difference between the ambient temperature and the sample temperature is significantly reduced, indicating excellent heat resistance.

[95]

[0071]

[96] The present invention is not limited to the examples, and can be manufactured in various different forms, and a person skilled in the art to which the present invention pertains will understand that the present invention can be embodied in other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the above-described examples are illustrative in all respects and not limiting.

Claims

1. a polyurethane which is a reaction product of a polyether polyol and an isocyanate compound; aerogel particles; A composite material for an insole, comprising:

2. 2. The composite material for an insole according to claim 1, wherein the polyether polyol has a hydroxyl value in the range of 20 to 40 mgKOH / g.

3. 2. The composite material for an insole according to claim 1, wherein the polyether-based polyol has a weight-average molecular weight in the range of 3,000 to 7,500.

4. 2. The composite material for an insole according to claim 1, wherein the polyether polyol has a viscosity at 25° C. in the range of 1,000 to 4,500 mPa·s.

5. The polyether polyol has a density at 20°C of 1.0 to 1.1 g / cm 3 The composite material for an insole according to claim 1 , wherein the thickness of the composite material for an insole is in the range of

6. 2. The composite material for an insole according to claim 1, wherein the aerogel particles have an average particle size of 50 μm or less.

7. 2. The composite material for an insole according to claim 1, wherein the average pore size of the aerogel particles is in the range of 5 nm to 20 nm.

8. The apparent density of the aerogel particles is 0.03 to 0.1 g / cm 3 The composite material for an insole according to claim 1 , wherein the thickness of the composite material for an insole is in the range of

9. The composite material for an insole according to claim 1 , wherein the aerogel particles have hydrophobic functional groups on the surfaces thereof.

10. The specific surface area (BET) of the aerogel particles is 600 to 800 m 2 The composite material for an insole according to claim 1 , wherein the elastic modulus is in the range of 1 / kg.

11. 2. The composite material for an insole according to claim 1, wherein the aerogel particles have a thermal conductivity of 0.022 W / mK or less.

12. The composite material for an insole according to claim 1, wherein the isocyanate compound contains hydroxyl groups (OH) in a range of 2.5 / mol to 3.0 / mol.

13. 2. The composite material for an insole according to claim 1, wherein the content of isocyanate groups (NCO) is in the range of 30% by weight to 33% by weight based on the isocyanate compound.

14. The composite material for an insole according to claim 1, wherein the isocyanate compound has a viscosity at 20°C in the range of 250 to 270 mPa·s.

15. The composite material for an insole according to claim 1, wherein the isocyanate compound has a viscosity at 25°C in the range of 210 to 230 mPa·s.

16. The isocyanate compound has a density at 25°C of 1.2 to 1.25 g / cm 3 The composite material for an insole according to claim 1 , wherein the thickness of the composite material for an insole is in the range of

17. Based on 100 parts by weight of the composite material for an insole, 95% to 99% by weight of the polyurethane; The composite material for an insole according to claim 1, comprising: 1% by weight to 5% by weight of the aerogel particles.

18. The polyurethane is 2. The composite material for an insole according to claim 1, wherein the isocyanate compound is contained in an amount ranging from 100 to 110 parts by weight based on 100 parts by weight of the polyether polyol.

19. The composite material for an insole according to claim 1, wherein the composite material for an insole has an Asker C hardness in the range of 25 to 35.

20. The composite material for an insole according to claim 1, wherein the composite material for an insole has an Asker F hardness in the range of 70 to 95.

21. The composite material for an insole has a density of 0.08 to 0.13 g / cm as measured by ASTM D792. 3 The composite material for an insole according to claim 1 , wherein the thickness of the composite material for an insole is in the range of

22. The composite material for an insole according to claim 1, wherein the composite material for an insole has a thermal conductivity in the range of 20 to 40 mW / mK.

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