Light wear-resistant EVA (Ethylene Vinyl Acetate) slow-rebound material as well as preparation method and application thereof

Abstract

The invention provides a lightweight wear-resistant EVA (Ethylene Vinyl Acetate) slow-rebound material as well as a preparation method and application thereof, and belongs to the technical field of materials for foamed shoes. The material comprises an ethylene-vinyl acetate copolymer, polyether, a maleic anhydride grafting modifier, white carbon black, butadiene rubber, a catalyst, a cross-linking agent and a surfactant. According to the invention, a slow-rebound polyether component is introduced into EVA, the slow-rebound polyether component and the EVA are modified through a specially-made surfactant, so that the compatibility of the slow-rebound polyether component and the EVA is improved, a tight cross-linked network is generated between the EVA and polyether through the combined action of a maleic anhydride grafted modifier and a cross-linking agent, and the cross-linked network can improve the density between materials, so that the material has good mechanical properties. Therefore, the material has supporting and flexible properties, has slow rebound performance, and is more comfortable to use.

Description

Technical Field

[0001] The invention relates to the technical field of foaming shoe materials, and in particular to a lightweight, wear-resistant EVA slow-rebound material and a preparation method and application thereof. Background Art

[0002] With the continuous improvement of living standards, people's awareness of scientific shoe wearing is constantly increasing. Lightweight, comfortable, wear-resistant and non-slip footwear products are becoming more and more popular. The sole material is a by-product of footwear products. With the development of footwear products, the quality requirements of sole materials are getting higher and higher. The wear resistance of the sole material is an important factor affecting the quality of the sole, especially for mountaineering enthusiasts, people who walk for a long time and people who participate in training.

[0003] At present, the main raw materials of the sole material mainly include one or more of TPR (thermoplastic elastomer), EVA, rubber, polyurethane, etc. Ethylene-vinyl acetate copolymer (EVA) has good plasticity, elasticity and processability, and the foamed material has the advantages of low density, good mechanical properties, easy coloring, etc., and is a traditional midsole material.

[0004] However, in special sports occasions (such as basketball, football, skiing and motorcycle riding, etc.), the soles are required to have shock absorption and cushioning properties, while the performance of existing EVA foam materials cannot meet the requirements. It is urgent to develop lightweight, wear-resistant and slow-rebound EVA foam materials to meet the requirements of shoe accessories that have special requirements on the wear resistance and rebound performance of the sole materials. Summary of the invention

[0005] The object of the present invention is to provide a lightweight, wear-resistant EVA slow-rebound material and a preparation method and application thereof, so as to solve the technical problem of improving the wear resistance and special rebound performance of the sole material.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a lightweight, wear-resistant EVA slow-rebound material, which is prepared from raw materials containing the following parts by mass:

[0008]

[0009]

[0010] Further, the polyether comprises one or more of GLR2000, Y-1030 and LW-1070;

[0011] The content of vinyl acetate in the ethylene-vinyl acetate copolymer is 20-40%.

[0012] Furthermore, the maleic anhydride grafted modifier comprises one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, maleic anhydride grafted POE and maleic anhydride grafted EVA.

[0013] Furthermore, the surfactant comprises a polyether-modified silicone surfactant, and the preparation method of the polyether-modified silicone surfactant comprises the following steps:

[0014] The hydrogen-containing silicone oil and allyl polyether are reacted under the action of chloroplatinic acid-isopropanol catalyst to obtain a transparent viscous liquid, which is the polyether-modified silicone surfactant.

[0015] Furthermore, the mass ratio of the hydrogen-containing silicone oil, allyl polyether and chloroplatinic acid-isopropanol catalyst is 10:5-15:0.01-0.03, the reaction temperature is 80-100° C., and the reaction time is 3-6 hours.

[0016] Further, the catalyst comprises triethylenediamine and / or dibutyltin dilaurate;

[0017] The cross-linking agent comprises one or more of dicumyl peroxide, di-tert-butyl peroxycumene and tert-amyl peroxy (2-ethylhexyl) carbonate.

[0018] The present invention also provides a method for preparing a lightweight, wear-resistant EVA slow-rebound material, comprising the following steps:

[0019] 1) mixing ethylene-vinyl acetate copolymer, polyether, maleic anhydride graft modifier, surfactant, white carbon black and butadiene rubber, and then adding a catalyst and a cross-linking agent and continuing to knead to obtain a blend;

[0020] 2) The blend is pressed into shape, and then the molded material is placed in a reactor and supercritical gas is introduced to perform supercritical foaming. After the gas is saturated, the pressure is released and the material is taken out to obtain a lightweight, wear-resistant EVA slow-rebound material.

[0021] Furthermore, in the step 1), the banburying temperature is independently 115 to 140° C., and the banburying time is independently 10 to 30 minutes.

[0022] Furthermore, the supercritical gas comprises supercritical CO2, supercritical N2, supercritical ethanol or supercritical propane.

[0023] Furthermore, the supercritical foaming temperature is 60-180° C., and the saturation is carried out for 2-4 hours at a pressure of 10-20 MPa; and the pressure release rate is 5-15 MPa / s.

[0024] The present invention also provides an application of a lightweight, wear-resistant EVA slow-rebound material in a shoe sole material or a slipper material.

[0025] Beneficial effects of the present invention:

[0026] The invention introduces a slow-rebound polyether component into EVA, and performs modification treatment on the two by a special surfactant to improve the compatibility of the two. Furthermore, through the joint action of a maleic anhydride grafting modifier and a crosslinking agent, a tight crosslinking network is generated between EVA and the polyether. The crosslinking network can increase the density between the materials, so that the material has both support and flexibility properties, has a slow-rebound property, and is more comfortable to use.

[0027] The present invention forms a cross-linked structure by adding butadiene rubber under the action of a catalyst, thereby improving the strength and wear resistance of the material, and also improving the thermal stability and aging resistance of the material; at the same time, adding white carbon black as a filler enhances the wear resistance of the cross-linked material, and the prepared material can be used in special occasions with high requirements for wear resistance.

[0028] The present invention adopts a supercritical foaming process, and the foamed material has a lower density and is thinner and lighter, so that the sole material made of the material is more comfortable to wear, effectively relieves the pressure on the sole of the foot, and reduces fatigue. Moreover, the process is more environmentally friendly and will not cause any pollution. DETAILED DESCRIPTION

[0029] The present invention provides a lightweight, wear-resistant EVA slow-rebound material, which is prepared from raw materials containing the following parts by mass:

[0030]

[0031] In the present invention, the content of the ethylene-vinyl acetate copolymer is preferably 45 to 55 parts by mass, more preferably 48 to 52 parts, and even more preferably 50 parts.

[0032] In the present invention, the content of the polyether is preferably 32 to 48 parts by mass, more preferably 36 to 44 parts, and even more preferably 40 parts.

[0033] In the present invention, the content of the maleic anhydride graft modifier is preferably 6 to 12 parts by mass, and more preferably 8 to 10 parts by mass.

[0034] In the present invention, the content of the white carbon black is preferably 25 to 35 parts by mass, more preferably 28 to 32 parts, and even more preferably 30 parts.

[0035] In the present invention, the content of the butadiene rubber is preferably 15 to 25 parts by mass, more preferably 18 to 22 parts, and even more preferably 20 parts.

[0036] In the present invention, the content of the catalyst is preferably 2 to 8 parts by mass, and more preferably 4 to 6 parts by mass.

[0037] In the present invention, the content of the cross-linking agent is preferably 2 to 4 parts by mass, and more preferably 3 parts by mass.

[0038] In the present invention, the content of the surfactant is preferably 15 to 45 parts by mass, more preferably 20 to 40 parts, and even more preferably 25 to 35 parts.

[0039] In the present invention, the polyether comprises one or more of GLR2000, Y-1030 and LW-1070, preferably GLR2000.

[0040] In the present invention, the content of vinyl acetate in the ethylene-vinyl acetate copolymer is 20 to 40%, preferably 22 to 38%, and more preferably 25 to 30%.

[0041] In the present invention, the maleic anhydride grafted modifier comprises one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, maleic anhydride grafted POE and maleic anhydride grafted EVA, preferably maleic anhydride grafted polyethylene.

[0042] In the present invention, the surfactant comprises a polyether-modified silicone surfactant, and the preparation method of the polyether-modified silicone surfactant comprises the following steps:

[0043] The hydrogen-containing silicone oil and allyl polyether are reacted under the action of chloroplatinic acid-isopropanol catalyst to obtain a transparent viscous liquid, which is the polyether-modified silicone surfactant.

[0044] In the present invention, the mass ratio of the hydrogen-containing silicone oil, allyl polyether and chloroplatinic acid-isopropanol catalyst is 10:5-15:0.01-0.03, preferably 10:6-12:0.01-0.02, and more preferably 10:10:0.02.

[0045] In the present invention, the reaction temperature is 80-100° C., preferably 85-95° C., and more preferably 90° C.; the reaction time is 3-6 h, and preferably 4-5 h.

[0046] In the present invention, the catalyst is preferably triethylenediamine and / or dibutyltin dilaurate.

[0047] In the present invention, the crosslinking agent is preferably one or more of dicumyl peroxide, di-tert-butyl peroxycumene and tert-amyl peroxy (2-ethylhexyl) carbonate.

[0048] The present invention also provides a method for preparing a lightweight, wear-resistant EVA slow-rebound material, comprising the following steps:

[0049] 1) mixing ethylene-vinyl acetate copolymer, polyether, maleic anhydride graft modifier, surfactant, white carbon black and butadiene rubber, and then adding a catalyst and a cross-linking agent and continuing to knead to obtain a blend;

[0050] 2) The blend is pressed into shape, and then the molded material is placed in a reactor and supercritical gas is introduced to perform supercritical foaming. After the gas is saturated, the pressure is released and the material is taken out to obtain a lightweight, wear-resistant EVA slow-rebound material.

[0051] In the present invention, in the step 1), the banburying temperature is independently 115-140° C., preferably 120-135° C., and more preferably 125° C.; the banburying time is independently 10-30 min, and preferably 20 min.

[0052] In the present invention, the supercritical gas is preferably supercritical CO2, supercritical N2, supercritical ethanol or supercritical propane.

[0053] In the present invention, the supercritical foaming temperature is 60-180°C, preferably 80-150°C, and more preferably 90-120°C; saturation is performed at a pressure of 10-20 MPa for 2-4 hours, and preferably saturation is performed at 15 MPa for 3 hours; the pressure release rate is 5-15 MPa / s, and preferably 10 MPa / s.

[0054] The present invention also provides an application of a lightweight, wear-resistant EVA slow-rebound material in a shoe sole material or a slipper material.

[0055] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0056] Example 1

[0057] Preparation of lightweight and wear-resistant EVA slow rebound material:

[0058] 1) 50 parts of ethylene-vinyl acetate copolymer (VA content 30%), 35 parts of polyether (GLR2000), 10 parts of maleic anhydride grafted polyethylene, 50 parts of surfactant, 30 parts of white carbon black and 20 parts of butadiene rubber were mixed and kneaded at 115° C. for 10 min, and then 5 parts of triethylenediamine and 3 parts of diisopropylbenzene peroxide were added and kneaded at 130° C. for 30 min to obtain a blend;

[0059] 2) The blend is pressed into shape, and then the molded material is placed in a reactor and supercritical CO2 is introduced to saturate the material at 115°C and 10MPa for 2 hours for supercritical foaming. After the gas is saturated, the pressure is released at a rate of 5MPa / s and the material is taken out to obtain a lightweight, wear-resistant EVA slow-rebound material.

[0060] The preparation method of the surfactant is as follows: 10 parts of hydrogenated silicone oil and 10 parts of allyl polyether are reacted at 90°C for 5 hours under the action of 0.02 parts of chloroplatinic acid-isopropanol catalyst to obtain a transparent viscous liquid, which is a polyether-modified silicone surfactant.

[0061] Example 2

[0062] Preparation of lightweight and wear-resistant EVA slow rebound material:

[0063] 1) 40 parts of ethylene-vinyl acetate copolymer (VA content 25%), 40 parts of polyether (Y-1030), 15 parts of maleic anhydride grafted polypropylene, 35 parts of surfactant, 25 parts of white carbon black and 25 parts of butadiene rubber were mixed and kneaded at 120° C. for 15 min, and then 6 parts of dibutyltin dilaurate and 5 parts of di-tert-butylperoxyisopropylbenzene were added and kneaded at 125° C. for 20 min to obtain a blend;

[0064] 2) The blend is pressed into shape, and then the molded material is placed in a reactor and introduced into supercritical N2 at 120°C and 20MPa for 3 hours for supercritical foaming. After the gas is saturated, the pressure is released at a rate of 5MPa / s and the material is taken out to obtain a lightweight, wear-resistant EVA slow-rebound material.

[0065] Wherein, the preparation method of the surfactant is the same as that in Example 1.

[0066] Example 3

[0067] Preparation of lightweight and wear-resistant EVA slow rebound material:

[0068] 1) 60 parts of ethylene-vinyl acetate copolymer (VA content 40%), 50 parts of polyether (LW-1070), 15 parts of maleic anhydride grafted EVA, 45 parts of surfactant, 40 parts of white carbon black and 30 parts of butadiene rubber were mixed and kneaded at 120° C. for 10 min, and then 10 parts of triethylenediamine and 5 parts of tert-amyl peroxy (2-ethylhexyl) carbonate were added and kneaded at 140° C. for 30 min to obtain a blend;

[0069] 2) The blend is pressed into shape, and then the molded material is placed in a reactor and introduced into supercritical ethanol to saturate at 90°C and 15MPa for 4 hours for supercritical foaming. After the gas is saturated, the pressure is released at a rate of 5MPa / s and the material is taken out to obtain a lightweight, wear-resistant EVA slow-rebound material.

[0070] Wherein, the preparation method of the surfactant is the same as that in Example 1.

[0071] Example 4

[0072] Preparation of lightweight and wear-resistant EVA slow rebound material:

[0073] 1) 55 parts of ethylene-vinyl acetate copolymer (VA content 35%), 45 parts of polyether (GLR2000), 8 parts of maleic anhydride grafted polypropylene, 48 parts of surfactant, 36 parts of white carbon black and 25 parts of butadiene rubber were mixed and kneaded at 115° C. for 10 min, and then 5 parts of dibutyltin dilaurate and 5 parts of diisopropylbenzene peroxide were added and kneaded at 140° C. for 30 min to obtain a blend;

[0074] 2) The blend is pressed into shape, and then the molded material is placed in a reactor and introduced into supercritical propane at 130° C. and 10 MPa for 2 hours for supercritical foaming. After the gas is saturated, the pressure is released at a rate of 5 MPa / s and the material is taken out to obtain a lightweight, wear-resistant EVA slow-rebound material.

[0075] Wherein, the preparation method of the surfactant is the same as that in Example 1.

[0076] Comparative Example 1

[0077] 1) 100g of natural rubber is added to an open mill and mixed over a roller, 5g of white carbon black, 1.5g of stearic acid, and 2g of zinc oxide are added for mixing, and then 0.8g of accelerator DM, 1.3g of sulfur, and 0.5g of antioxidant RD are added, the mixture is mixed and left to stand for 10h, and then pre-vulcanized on a flat vulcanizer at a pre-vulcanization temperature of 120°C, a vulcanization pressure of 25MPa, and a vulcanization time of 8min to obtain a pre-vulcanized rubber sole material;

[0078] 2) The pre-vulcanized wear-resistant rubber sole material is placed in a reactor for supercritical foaming, and supercritical carbon dioxide foaming gas is introduced. It is saturated at a temperature of 115° C. and a pressure of 15 MPa for 3 hours, and then the pressure is reduced to normal pressure at a pressure relief rate of 10 MPa / s. The complete vulcanization is carried out in an oven at a complete vulcanization temperature of 180° C. and a complete vulcanization time of 30 minutes to obtain a rubber sole foam material.

[0079] Comparative Example 2

[0080] Same as Example 1, except that no white carbon black is added.

[0081] Comparative Example 3

[0082] Same as Example 2, except that no polyether is added and only EVA is used as the main material.

[0083] Comparative Example 4

[0084] Same as Example 3, except that the added surfactant is sodium dodecylbenzene sulfonate.

[0085] Performance Test:

[0086] Drop ball rebound: tested according to the method of GB / T6670-2008.

[0087] Density: tested using KW-300A microcomputer electronic density meter.

[0088] The results are shown in Table 1 below.

[0089] Table 1 Test results

[0090] project Ball rebound rate / % <![CDATA[Density / g / cm 3 > Example 1 40 0.45 Example 2 42 0.44 Example 3 41 0.39 Example 4 43 0.41 Comparative Example 1 73 0.21 Comparative Example 2 45 0.35 Comparative Example 3 69 0.26 Comparative Example 4 72 0.19

[0091] It can be seen from the results in Table 1 that the slow rebound material prepared by the present invention has a low rebound rate and a relatively high density.

[0092] Wear resistance test: The DIN abrasion tester was used for the test. The prepared lightweight wear-resistant EVA slow rebound material was made into a cylindrical sample with a diameter of 16 mm and a thickness of 8 mm. Under the test conditions of a friction distance of 40 mm and a load of 10 N, the transversely moving sample and the gauze on the drum were rubbed. The wear resistance of the sample was represented by the wear volume of the outsole. The test results are shown in Table 2.

[0093] Table 2 Wear resistance test

[0094] project <![CDATA[Wear volume (mm 3 )]]> Example 1 60.84 Example 2 65.32 Example 3 70.15 Example 4 61.36 Comparative Example 1 256.08 Comparative Example 2 135.62 Comparative Example 3 155.34 Comparative Example 4 189.35

[0095] From the results in Table 2, it can be seen that the slow rebound material prepared by the present invention has excellent wear resistance, and the raw materials interact with each other to produce a special cross-linked structure, which improves the wear resistance of the material. The material of the present invention can be used to prepare the sole material or the slipper material to improve the service life and wearing comfort of the shoe material.

[0096] It can be seen from the above embodiments that the present invention provides a lightweight, wear-resistant EVA slow-rebound material and its preparation method and application. The present invention introduces a slow-rebound polyether component into EVA, and modifies the two by a special surfactant to improve the compatibility of the two. Through the joint action of the maleic anhydride grafting modifier and the crosslinking agent, a tight crosslinking network is generated between EVA and polyether. This crosslinking network can increase the density between the materials, so that the material has both support and flexibility, has slow rebound performance, and is more comfortable to use.

[0097] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A lightweight, wear-resistant EVA slow-rebound material, characterized in that: Prepared from the following raw materials in parts by weight:

2. The lightweight, wear-resistant EVA slow-rebound material according to claim 1, characterized in that: The polyether comprises one or more of GLR2000, Y-1030 and LW-1070; The content of vinyl acetate in the ethylene-vinyl acetate copolymer is 20-40%.

3. The lightweight, wear-resistant EVA slow-rebound material according to claim 1 or 2, characterized in that: The maleic anhydride grafted modifier comprises one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, maleic anhydride grafted POE and maleic anhydride grafted EVA.

4. The lightweight, wear-resistant EVA slow-rebound material according to claim 3, characterized in that: The surfactant comprises a polyether-modified silicone surfactant, and the preparation method of the polyether-modified silicone surfactant comprises the following steps: The hydrogen-containing silicone oil and allyl polyether are reacted under the action of chloroplatinic acid-isopropanol catalyst to obtain a transparent viscous liquid, which is the polyether-modified silicone surfactant.

5. The lightweight, wear-resistant EVA slow-rebound material according to claim 4, characterized in that: The mass ratio of the hydrogen-containing silicone oil, the allyl polyether and the chloroplatinic acid-isopropanol catalyst is 10:5-15:0.01-0.03, the reaction temperature is 80-100°C, and the reaction time is 3-6h.

6. The lightweight, wear-resistant EVA slow-rebound material according to claim 1, 2 or 5, characterized in that: The catalyst comprises triethylenediamine and / or dibutyltin dilaurate; The cross-linking agent comprises one or more of dicumyl peroxide, di-tert-butyl peroxycumene and tert-amyl peroxy (2-ethylhexyl) carbonate.

7. The method for preparing the lightweight, wear-resistant EVA slow-rebound material according to any one of claims 1 to 6, characterized in that: The following steps are involved: 1) mixing ethylene-vinyl acetate copolymer, polyether, maleic anhydride graft modifier, surfactant, white carbon black and butadiene rubber, and then adding a catalyst and a cross-linking agent and continuing to knead to obtain a blend; 2) The blend is pressed into shape, and then the molded material is placed in a reactor and supercritical gas is introduced to perform supercritical foaming. After the gas is saturated, the pressure is released and the material is taken out to obtain a lightweight, wear-resistant EVA slow-rebound material.

8. The method for preparing the lightweight, wear-resistant EVA slow-rebound material according to claim 7, characterized in that: In the step 1), the banburying temperature is independently 115 to 140° C., and the banburying time is independently 10 to 30 minutes; The supercritical gas includes supercritical CO2, supercritical N2, supercritical ethanol or supercritical propane.

9. The method for preparing the lightweight, wear-resistant EVA slow-rebound material according to claim 8, characterized in that: The supercritical foaming temperature is 60-180° C., and the saturation is carried out for 2-4 hours at a pressure of 10-20 MPa; the pressure release rate is 5-15 MPa / s.

10. Use of the lightweight, wear-resistant EVA slow-rebound material according to any one of claims 1 to 6 in shoe sole materials or slipper materials.

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