Elastic material for sole, preparation method and sports shoes thereof

Abstract

The present invention relates to the technical field of shoe materials, and specifically discloses an elastic material for soles, a preparation method and sports shoes thereof. The components of the elastic material are: EVA, natural rubber, graphene-modified regenerated rubber, active zinc oxide, zinc stearate, stearic acid, an antioxidant, a crosslinking agent, a flow aid, and a foaming agent. The present invention modifies the regenerated rubber by graphene oxide, and the modification process includes preparing emulsion-dispersed regenerated rubber and graphene oxide, ultrasonically grafting unsaturated short-chain rubber molecules on the surface of graphene oxide, and in-situ polymerization of unsaturated short-chain rubber molecules to form long-chain molecules and esterification reaction of an activator to combine with graphene, thereby enhancing the strength and resilience of the regenerated rubber. Solid-phase shear crushing is conducive to further desulfurization and the generation of more unsaturated short-chain rubber molecules, which is conducive to obtaining longer chains.

Description

Technical Field

[0001] The present invention relates to the technical field of shoe materials, in particular to an elastic material for shoe soles, a preparation method and sports shoes thereof. Background Art

[0002] EVA is the abbreviation of ethylene-vinyl acetate copolymer. In addition to having good elasticity like rubber, EVA products are also different from rubber in flexibility, low temperature resistance, transparency, surface gloss, etc. Products made of EVA resin can still have good flexibility at -50°C. EVA is a common material for soles. In order to enhance its performance, rubber is generally blended and added, such as the Chinese public document (CN105585769A).

[0003] Recycled rubber has always been an important raw material for the world's rubber industry. On the one hand, it can replace rubber and alleviate the serious shortage of natural rubber. On the other hand, it enables the recycling of waste rubber and solves the problem of waste rubber polluting the environment. However, during the regeneration process, the recycled rubber of vulcanized natural rubber or vulcanized butadiene rubber often cuts off the rubber cross-linking points and the rubber main chain at the same time without distinction. According to statistics, about 30% of the rubber main chain molecules are damaged, forming sulfur-containing rubber molecules and sulfur-free unsaturated short-chain rubber molecules, resulting in a decrease in the molecular weight that dominates the rubber performance, and then the recycled rubber has low mechanical strength and poor elasticity. Summary of the invention

[0004] The present invention aims to provide an elastic material for soles, a preparation method and sports shoes thereof, so as to recycle recycled rubber and improve the mechanical properties and elasticity of the soles containing the recycled rubber.

[0005] The technical solution adopted by the present invention is:

[0006] An elastic material for shoe soles, comprising the following components in parts by weight: 50-60 parts of EVA, 10-15 parts of natural rubber, 30-40 parts of graphene-modified recycled rubber, 1-2 parts of active zinc oxide, 0.5-1.0 parts of zinc stearate, 0.8-1.0 parts of stearic acid, 0.5-0.8 parts of antioxidant, 0.5-0.8 parts of cross-linking agent, 4-6 parts of flow aid, and 2-3 parts of foaming agent;

[0007] The method for preparing the graphene-modified regenerated rubber comprises the following steps:

[0008] S01. Select unsaturated rubber reclaimed rubber and perform solid phase shear crushing;

[0009] S02, putting the reclaimed rubber in step S01 into an internal mixer for pre-mixing for 10 to 15 minutes, then pouring it out onto an open mixer, adding sulfonated aromatic polymer and water while mixing, mixing until the particles are in a water-emulsion state, then discharging the material and diluting it with water to obtain a reclaimed rubber latex;

[0010] S03, adding graphene oxide dispersion to the regenerated rubber latex of step S02, ultrasonically reacting for 40min to 60min to graft unsaturated short-chain rubber molecules onto GO (graphene oxide), then adding BPO (dibenzoyl peroxide) and introducing nitrogen, heating to 125°C to 130°C to allow the regenerated rubber latex and the unsaturated short-chain rubber molecules on the graphene surface to polymerize in situ, and the reaction time is 60min to 90min;

[0011] S04. After vacuum drying, add an appropriate amount of petroleum ether, stir evenly, then add trifluoroacetic anhydride, stir and react for 10min to 20min to allow the activator in the regenerated rubber to esterify and bind to the partially reduced graphene oxide, then heat to remove the petroleum ether and trifluoroacetic anhydride and completely thermally reduce, wash and filter to obtain graphene-modified regenerated rubber.

[0012] Preferably, the sulfonated aromatic polymer is naphthalenesulfonic acid formaldehyde condensate sodium salt, and the added amount is 2% to 5% of the mass of the reclaimed rubber.

[0013] Preferably, the unsaturated rubber is natural rubber and / or butadiene rubber.

[0014] Preferably, the amount of graphene oxide used is 30% to 40% of the mass of the regenerated rubber.

[0015] Preferably, the antioxidant is at least one of antioxidant NBC, antioxidant RD, and antioxidant 4010NA.

[0016] Preferably, the cross-linking agent is prepared by mixing insoluble sulfur and dicumyl peroxide in a mass ratio of 2:1.

[0017] Preferably, the flow aid is paraffin.

[0018] Preferably, the natural rubber is a rubber material that has been stored naturally for 72 hours after mastication, and the mastication method is: putting it into an internal mixer for mastication for 15 minutes to 20 minutes, and the temperature is controlled at 150°C to 155°C.

[0019] The present invention also provides a method for preparing an elastic material for a shoe sole, which specifically comprises the following steps:

[0020] S1, put the EVA, natural rubber, graphene modified regenerated rubber and antioxidant in the said weight parts into the internal mixer for internal mixing for 10min to 15min, and control the temperature at 135°C to 140°C to obtain a rubber internal mixing material;

[0021] S2, pour out the rubber mixed material after mixing, and then put it into the open mixer to thin it 2-3 times to produce sheets; put the thinned rubber mixed material into the internal mixer again, and then add the active zinc oxide, zinc stearate, stearic acid and flow aid in the above-mentioned parts by weight to mix for 15min-20min, and control the temperature at 110℃-115℃;

[0022] S3, adding the foaming agent and the cross-linking agent in the said weight parts into the internal mixer and then mixing for 5min to 8min to obtain a rubber mixture;

[0023] S4, thin the mixed rubber poured out after mixing on an open mixer for 2-3 times to produce a sheet, and then put it on an extruder for extrusion granulation to obtain a modified masterbatch;

[0024] S5. Accurately weigh the modified masterbatch according to the ratio, put it into the mold, heat and pressurize it, and vulcanize it into shape.

[0025] The present invention further provides a sports shoe, comprising a sole, wherein the sole is prepared by the above-mentioned preparation method.

[0026] Beneficial effects of the present invention:

[0027] The present invention modifies the reclaimed rubber by graphene oxide, and the reclaimed rubber of the unsaturated rubber contains an activator, a softener, a sulfur-containing rubber molecule and a sulfur-free unsaturated short-chain rubber molecule. The modification process includes preparing emulsion-dispersed reclaimed rubber and graphene oxide, ultrasonically grafting unsaturated short-chain rubber molecules on the surface of graphene oxide, and in-situ polymerization of unsaturated short-chain rubber molecules to form long-chain molecules and esterification reaction of the activator to combine with graphene, thereby enhancing the strength and resilience of the reclaimed rubber. Solid-phase shear crushing is conducive to further desulfurization and the generation of more unsaturated short-chain rubber molecules, which is conducive to obtaining longer chains.

[0028] The sulfonated aromatic polymer is added to the emulsion of the present invention, which, on the one hand, enables the regenerated rubber to disperse and support the emulsion, and on the other hand, utilizes the amphoteric surfactant effect of the sulfonated aromatic polymer to evenly disperse the graphene oxide and the regenerated rubber latex.

[0029] The tensile strength of the elastic material of the present invention is above 22 MPa (GB / T528), and the DIN abrasion is less than 55 mm. 3 (GB / T9867), the rebound value is more than 50% (GB / T10652). Compared with the conventional formula using the same amount of reclaimed rubber without performing steps S02-S04 and the same other components and amounts, the tensile strength and rebound value of the present invention are significantly improved. DETAILED DESCRIPTION Example 1

[0030] The present embodiment provides a sports shoe, including a sole, which is composed of the following components in parts by weight: 60 parts of EVA, 10 parts of natural rubber, 35 parts of graphene-modified recycled rubber, 2 parts of active zinc oxide, 0.5 parts of zinc stearate, 1.0 parts of stearic acid, 0.6 parts of antioxidant, 0.8 parts of cross-linking agent, 5 parts of flow aid, and 2.5 parts of foaming agent.

[0031] The antioxidant is NBC; the flow aid is paraffin; the foaming agent is azodicarbonamide; and the cross-linking agent is prepared by mixing insoluble sulfur and dicumyl peroxide in a mass ratio of 2:1.

[0032] The natural rubber is a rubber material that has been stored naturally for 72 hours after mastication. The mastication method is: putting it into an internal mixer for mastication for 20 minutes, and the temperature is controlled at 150°C.

[0033] The method for preparing the sole comprises the following steps:

[0034] S0. Preparation of graphene-modified recycled rubber.

[0035] S1. Put the EVA, natural rubber, graphene-modified regenerated rubber and antioxidant in the said weight proportions into an internal mixer and mix them for 15 minutes, and control the temperature at 135° C. to obtain a rubber internal mixer.

[0036] S2, pour out the kneaded rubber mixture, and then put it on an open mixer to thin it 3 times to produce sheets; put the thinned rubber mixture into the internal mixer again, and then add the active zinc oxide, zinc stearate, stearic acid and flow aid in the above-mentioned parts by weight to mix for 20 minutes, and the temperature is controlled at 110°C.

[0037] S3, adding the foaming agent and the cross-linking agent in the said weight proportions into the internal mixer and then mixing for 5 minutes to obtain a rubber mixture.

[0038] S4. Thin the mixed rubber poured out after mixing on an open mixer for 3 times to produce sheets, and then put them on an extruder for extrusion granulation to obtain modified masterbatch.

[0039] S5. Accurately weigh the modified masterbatch according to the ratio, put it into the mold, heat and pressurize it, and vulcanize it into shape.

[0040] The graphene-modified regenerated rubber of this embodiment is prepared by the following preparation method, which specifically comprises the following steps:

[0041] S01. Select reclaimed natural rubber and perform solid phase shear crushing;

[0042] S02, putting the reclaimed rubber in step S01 into an internal mixer for pre-mixing for 15 minutes, then pouring it out onto an open mixer, adding 4% of the mass of the reclaimed rubber sodium salt of naphthalenesulfonic acid formaldehyde condensate and water while mixing, mixing until the particles are in a water emulsion, then discharging the material and diluting it with water to obtain a reclaimed rubber latex;

[0043] S03, adding graphene oxide dispersion to the regenerated rubber latex of step S02, the amount of graphene oxide used is 35% of the mass of the regenerated rubber, and performing ultrasonic reaction at 800W for 60min to graft the unsaturated short-chain rubber molecules onto GO, then adding BPO and introducing nitrogen, heating to 125°C to allow the regenerated rubber latex and the unsaturated short-chain rubber molecules on the graphene surface to undergo in-situ polymerization reaction, and the reaction time is 80min;

[0044] S04. After vacuum drying, add an appropriate amount of petroleum ether, stir evenly, then add trifluoroacetic anhydride, stir and react for 10 minutes to allow the activator in the regenerated rubber to esterify and bind to the partially reduced graphene oxide, then heat to remove the petroleum ether and trifluoroacetic anhydride and completely thermally reduce, wash and filter to obtain graphene-modified regenerated rubber. Example 2

[0045] The present embodiment provides a sports shoe, including a sole, wherein the sole includes the following components in parts by weight: 50 parts of EVA, 12 parts of natural rubber, 40 parts of graphene-modified recycled rubber, 1.5 parts of active zinc oxide, 1.0 parts of zinc stearate, 1.0 parts of stearic acid, 0.5 parts of antioxidant, 0.5 parts of cross-linking agent, 6 parts of flow aid, and 2 parts of foaming agent.

[0046] The antioxidant is antioxidant RD; the flow aid is paraffin; the foaming agent is azodicarbonamide; the cross-linking agent is insoluble sulfur and diisopropylbenzene peroxide prepared in a mass ratio of 2:1; the natural rubber is a rubber material that has been naturally stored for 72 hours after mastication, and the mastication method is: put it into an internal mixer for mastication for 120 minutes, and the temperature is controlled at 150°C.

[0047] The method for preparing the sole comprises the following steps:

[0048] S0. Preparation of graphene-modified recycled rubber.

[0049] S1. Put the EVA, natural rubber, graphene-modified regenerated rubber and antioxidant in the said weight proportions into an internal mixer and mix them for 10 minutes, and control the temperature at 140° C. to obtain a rubber internal mixer.

[0050] S2, pour out the rubber mixture after mixing, and then put it into an open mixer to thin it 3 times to produce sheets; put the thinned rubber mixture into the internal mixer again, and then add the active zinc oxide, zinc stearate, stearic acid and flow aid in the above-mentioned parts by weight to mix for 15 minutes, and control the temperature at 115°C.

[0051] S3, adding the foaming agent and the cross-linking agent in the said parts by weight into the internal mixer, and then mixing for 8 minutes to obtain a rubber mixture.

[0052] S4. Thin the mixed rubber poured out after mixing on an open mixer for 3 times to produce sheets, and then put them on an extruder for extrusion granulation to obtain modified masterbatch.

[0053] S5. Accurately weigh the modified masterbatch according to the ratio, put it into the mold, heat and pressurize it, and vulcanize it into shape.

[0054] The graphene-modified regenerated rubber of this embodiment is prepared by the following preparation method, which specifically comprises the following steps:

[0055] S01, select recycled rubber of natural rubber and butadiene rubber and perform solid phase shear crushing;

[0056] S02, putting the reclaimed rubber in step S01 into an internal mixer for pre-mixing for 10 minutes, then pouring it out onto an open mixer, adding 2% of the mass of the reclaimed rubber sodium salt of naphthalenesulfonic acid formaldehyde condensate and water while mixing, mixing until the particles are in a water emulsion, then discharging the material and diluting it with water to obtain a reclaimed rubber latex;

[0057] S03, adding graphene oxide dispersion to the regenerated rubber latex of step S02, the amount of graphene oxide used is 30% of the mass of the regenerated rubber, and ultrasonically reacting at 800W for 60 minutes to graft the unsaturated short-chain rubber molecules onto GO, and then adding BPO and introducing nitrogen, heating to 130°C to allow the regenerated rubber latex and the unsaturated short-chain rubber molecules on the graphene surface to react in situ, and the reaction time is 60 minutes;

[0058] S04. After vacuum drying, add an appropriate amount of petroleum ether, stir evenly, then add trifluoroacetic anhydride, stir and react for 20 minutes to allow the activator in the regenerated rubber to esterify and bind to the partially reduced graphene oxide, then heat to remove the petroleum ether and trifluoroacetic anhydride and completely thermally reduce, wash and filter to obtain graphene-modified regenerated rubber. Example 3

[0059] The present embodiment provides a sports shoe, including a sole, which is composed of the following components in parts by weight: 55 parts of EVA, 15 parts of natural rubber, 30 parts of graphene-modified recycled rubber, 1 part of active zinc oxide, 0.8 parts of zinc stearate, 0.8 parts of stearic acid, 0.8 parts of antioxidant, 0.6 parts of cross-linking agent, 4 parts of flow aid, and 3 parts of foaming agent.

[0060] The antioxidant is antioxidant 4010NA; the flow aid is paraffin; the foaming agent is azodicarbonamide; the cross-linking agent is insoluble sulfur and diisopropylbenzene peroxide prepared in a mass ratio of 2:1; the natural rubber is a rubber material that has been naturally stored for 72 hours after mastication, and the mastication method is: put it into an internal mixer for mastication for 20 minutes, and the temperature is controlled at 150°C.

[0061] The method for preparing the sole comprises the following steps:

[0062] S0. Preparation of graphene-modified recycled rubber.

[0063] S1. Put the EVA, natural rubber, graphene-modified regenerated rubber and antioxidant in the said weight proportions into an internal mixer and mix them for 15 minutes, and control the temperature at 140° C. to obtain a rubber internal mixer.

[0064] S2, pour out the kneaded rubber mixture, and then put it on an open mixer to thin it 3 times to produce sheets; put the thinned rubber mixture into the internal mixer again, and then add the active zinc oxide, zinc stearate, stearic acid and flow aid in the above-mentioned parts by weight to mix for 20 minutes, and the temperature is controlled at 115°C.

[0065] S3, adding the foaming agent and the cross-linking agent in the said weight proportions into the internal mixer and then mixing for 5 minutes to obtain a rubber mixture.

[0066] S4. Thin the mixed rubber poured out after mixing on an open mixer for 3 times to produce sheets, and then put them on an extruder for extrusion granulation to obtain modified masterbatch.

[0067] S5. Accurately weigh the modified masterbatch according to the ratio, put it into the mold, heat and pressurize it, and vulcanize it into shape.

[0068] The graphene-modified regenerated rubber of this embodiment is prepared by the following preparation method, which specifically comprises the following steps:

[0069] S1. Select the reclaimed rubber of butadiene rubber and perform solid phase shearing and crushing;

[0070] S2, putting the reclaimed rubber in step S01 into an internal mixer for pre-mixing for 15 minutes, then pouring it out onto an open mixer, adding 5% of the mass of the reclaimed rubber sodium salt of naphthalenesulfonic acid formaldehyde condensate and water while mixing, mixing until the particles are in a water emulsion, then discharging the material and diluting it with water to obtain a reclaimed rubber latex;

[0071] S3, adding graphene oxide dispersion to the regenerated rubber latex of step S02, the amount of graphene oxide used is 40% of the mass of the regenerated rubber, and ultrasonically reacting at 800W for 50min to graft the unsaturated short-chain rubber molecules onto GO, then adding BPO and introducing nitrogen, heating to 125°C to allow the regenerated rubber latex and the unsaturated short-chain rubber molecules on the graphene surface to react in situ, and the reaction time is 90min;

[0072] S4. After vacuum drying, add an appropriate amount of petroleum ether, stir evenly, then add trifluoroacetic anhydride, stir and react for 5 minutes to allow the activator in the regenerated rubber to esterify and bind to the partially reduced graphene oxide, then heat to remove the petroleum ether and trifluoroacetic anhydride and completely thermally reduce, wash and filter, and obtain graphene-modified regenerated rubber.

[0073] Comparative Example 1

[0074] The only difference between this comparative example and the above-mentioned Example 1 is that an equal amount of reclaimed rubber of butadiene rubber after solid phase shearing and crushing is used to replace the graphene-modified reclaimed rubber.

[0075] Physical property tests were performed on Examples 1-3 of the present invention and Comparative Example 1, respectively, wherein the tensile strength was measured according to GB / T528-2009, the DIN abrasion was measured according to GB / T9867-2008, and the rebound value was measured according to GB / T10652-2001. The results are shown in Table 1.

[0076] Table 1: Physical property test results of Examples 1-3 of the present invention and Comparative Example 1

[0077]

[0078] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An elastic material for a shoe sole, characterized in that: The invention is composed of the following components in parts by weight: 50-60 parts of EVA, 10-15 parts of natural rubber, 30-40 parts of graphene-modified recycled rubber, 1-2 parts of active zinc oxide, 0.5-1.0 parts of zinc stearate, 0.8-1.0 parts of stearic acid, 0.5-0.8 parts of antioxidant, 0.5-0.8 parts of cross-linking agent, 4-6 parts of flow aid, and 2-3 parts of foaming agent; The natural rubber is a rubber material that has been naturally stored for 72 hours after being masticated, and the mastication method is: putting it into an internal mixer for mastication for 15 minutes to 20 minutes, and the temperature is controlled at 150° C. to 155° C.; The method for preparing the graphene-modified regenerated rubber comprises the following steps: S01, selecting reclaimed rubber of unsaturated rubber and performing solid phase shearing and crushing, wherein the unsaturated rubber is natural rubber and / or butadiene rubber; S02, putting the reclaimed rubber in step S01 into an internal mixer for pre-mixing for 10-15 minutes, then pouring it out onto an open mixer, adding sulfonated aromatic polymer and water while mixing, mixing until the particles are in a water-emulsified state, then discharging the material and diluting with water to obtain a reclaimed rubber latex; the sulfonated aromatic polymer is a sodium salt of naphthalenesulfonic acid formaldehyde condensate, and the amount added is 2%-5% of the mass of the reclaimed rubber; S03, adding graphene oxide dispersion to the regenerated rubber latex of step S02, wherein the amount of graphene oxide is 30% to 40% of the mass of the regenerated rubber, and ultrasonically reacting for 40min to 60min to allow the unsaturated short-chain rubber molecules to be grafted onto GO, and then adding BPO and introducing nitrogen, heating to 125° C. to 130° C. to allow the regenerated rubber latex and the unsaturated short-chain rubber molecules on the graphene surface to undergo in-situ polymerization reaction, and the reaction time is 60min to 90min; S04. After vacuum drying, add an appropriate amount of petroleum ether, stir evenly, then add trifluoroacetic anhydride, stir and react for 10min to 20min to allow the activator in the regenerated rubber to esterify and bind to the partially reduced graphene oxide, then heat to remove the petroleum ether and trifluoroacetic anhydride and completely thermally reduce, wash and filter to obtain graphene-modified regenerated rubber.

2. The elastic material for the sole according to claim 1, characterized in that: The antioxidant is at least one of antioxidant NBC, antioxidant RD, and antioxidant 4010NA.

3. The elastic material for shoe soles according to claim 1, characterized in that: The cross-linking agent is prepared by mixing insoluble sulfur and dicumyl peroxide in a mass ratio of 2:

1.

4. The elastic material for shoe soles according to claim 1, characterized in that: The flow aid is paraffin.

5. A method for preparing the elastic material for the sole according to any one of claims 1 to 4, characterized in that: The specific steps include: S1, put the EVA, natural rubber, graphene modified regenerated rubber and antioxidant in the said weight parts into the internal mixer for internal mixing for 10min to 15min, and control the temperature at 135°C to 140°C to obtain a rubber internal mixing material; S2, pour out the rubber mixed material after mixing, and then put it into the open mixer to thin it 2-3 times to produce sheets; put the thinned rubber mixed material into the internal mixer again, and then add the active zinc oxide, zinc stearate, stearic acid and flow aid in the above-mentioned parts by weight to mix for 15min-20min, and control the temperature at 110℃-115℃; S3, adding the foaming agent and the cross-linking agent in the said weight parts into the internal mixer and then mixing for 5min to 8min to obtain a rubber mixture; S4, thin the mixed rubber poured out after mixing on an open mixer for 2-3 times to produce a sheet, and then put it on an extruder for extrusion granulation to obtain a modified masterbatch; S5. Accurately weigh the modified masterbatch according to the ratio, put it into the mold, heat and pressurize it, and vulcanize it into shape.

6. Sports shoes, including a sole, characterized in that The sole is made of the elastic material for soles prepared by the preparation method as claimed in claim 5.

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