阅读说明：本技术 一种可生物降解发泡鞋底的制备方法 (Preparation method of biodegradable foamed sole ) 是由 林剑坤 卢鑫 王育玲 陈振裕 罗显发 丁思博 廖毅彬 于 2019-10-28 设计创作，主要内容包括：本发明属于有机高分子化合物技术领域,特别涉及一种可生物降解发泡鞋底的制备方法,由下述组分按重量份原料制得：回收EVA膜、EVA、淀粉接枝EVA、马来酸酐接枝POE、发泡剂AC、交联剂BIBP、硬脂酸锌、硬脂酸、无机抗菌粉,经过密炼、开炼、造粒,再经一次射出成型,得到含淀粉接枝EVA的可生物降解发泡鞋底；本发明制备的可生物降解发泡鞋底,解决了现有技术中淀粉亲水表面和EVA之间不相容的问题,增加了淀粉与EVA共混界面粘结力,并减少界面间隙,进而提高了共混物综合性能,提升了鞋底材料的性能,并具备可生物降解性,能缓解白色污染带来的环境问题。(The invention belongs to the technical field of organic high molecular compounds, and particularly relates to a preparation method of a biodegradable foamed sole, which is prepared from the following raw materials in parts by weight: recovering the EVA film, the EVA, the starch grafted EVA, the maleic anhydride grafted POE, the foaming agent AC, the crosslinking agent BIBP, the zinc stearate, the stearic acid and the inorganic antibacterial powder, banburying, milling, granulating and performing injection molding once again to obtain the biodegradable foamed sole containing the starch grafted EVA; the biodegradable foamed sole prepared by the invention solves the problem of incompatibility between the starch hydrophilic surface and EVA in the prior art, increases the bonding force of the blending interface of the starch and the EVA, reduces the interface gap, further improves the comprehensive performance of the blend, improves the performance of the sole material, has biodegradability and can relieve the environmental problem caused by white pollution.)

1. A preparation method of biodegradable foamed shoe soles is characterized by comprising the following steps:

(a) crushing the waste EVA material to obtain a crushed material;

(b) 75 parts of crushed materials, 3 parts of mineral oil and 5 parts of EVA7870S 5 are subjected to banburying and open milling and then are calendered into a recycled EVA film with the thickness of 0.01mm-0.05 mm;

(c) preparing biodegradable material rice, wherein the biodegradable material rice is prepared from the following components in parts by weight:

firstly, mixing the raw materials except the crosslinking agent BIBP and the foaming agent AC, banburying, adjusting banburying temperature to 88-93 ℃, keeping for 4 minutes and then stirring; when the banburying temperature is increased to 97 ℃, turning materials for the second time; when the banburying temperature is increased to 103 ℃, turning for the third time, and adding the crosslinking agent BIBP and the foaming agent AC; when the banburying temperature is increased to 109 ℃, turning materials for the fourth time; carrying out fifth material turning when the banburying temperature is raised to 115 ℃, carrying out banburying for 1 minute, and finally carrying out material pouring, open milling and granulation to obtain biodegradable material rice;

(d) and adding the biodegradable material into a machine, automatically sucking the material, and performing one-time injection molding at the gun temperature of 90-108 ℃, the mold temperature of 175-180 ℃ and the time of 170-200 seconds to obtain the foamed sole.

2. The method for preparing biodegradable foamed shoe sole according to claim 1, wherein the starch grafted EVA in step (c) is prepared by dissolving starch in water, heating to 93 ℃, gelatinizing for 35min, cooling to 55 ℃, adding ammonium persulfate initiator, adding EVA emulsion, heating to 85 ℃, reacting for 3-4 hours, adding absolute ethanol for precipitation, filtering, and drying to obtain starch grafted EVA.

3. The method for preparing biodegradable foamed shoe sole according to claim 1, wherein the starch graft ratio is 25-38%.

4. The method for preparing biodegradable foamed shoe sole according to claim 1, wherein the waste EVA material in the step (a) comprises scrap, defective products, waste products and leftover materials generated in the production of EVA shoe sole.

5. The method for preparing biodegradable foamed shoe sole according to claim 1, wherein the crushed material in step (a) is strip-shaped crushed material with thickness of 1.3mm-3mm and width of 2mm-5 mm.

6. The method for preparing biodegradable foamed shoe sole according to claim 1, wherein the thickness of said recycled EVA film in the step (a) is 0.01mm-0.02 mm.

7. The method for preparing biodegradable foamed shoe sole according to claim 1, wherein in the step (c), the grafting ratio of maleic anhydride to POE is 1.3%.

8. The method for preparing biodegradable foamed shoe sole according to claim 1, wherein said biodegradable material is cake-shaped, having a thickness of 1.5mm to 4mm and a diameter of 4mm to 8 mm.

9. The method for preparing biodegradable foamed shoe sole according to claim 1, wherein the waste EVA material is crushed by a crusher, the crusher is of a double-roller semi-open type, the distance between the front roller and the rear roller is 1mm-4mm, the speed ratio of the front roller to the rear roller is 1:1-2, and the temperature of the rollers is 0 ℃ to 50 ℃.

Technical Field

The invention belongs to the technical field of organic high molecular compounds, and particularly relates to a preparation method of a biodegradable foamed sole.

Background

In life, because of the characteristics of light weight, high elasticity, low cost and the like, EVA has a very important position in the shoe material industry.

The existing biodegradable foamed sole adopts: adding starch, EVA, an elastomer, an inorganic filler, other auxiliaries, a starch initiator ammonium persulfate, polyolefin and polyolefin elastomer initiator BPO, a foaming agent and a crosslinking agent into an internal mixer, mixing to obtain a plasticized composite material of starch grafted polyolefin and a polyolefin elastomer, then mixing and pulling a sheet by using an open mill, and finally foaming by using a flat vulcanizing machine to obtain the composite foamed shoe material of the starch dry-method grafted polyolefin and the polyolefin elastomer.

However, in the process of implementing the technical solution of the invention in the embodiments of the present application, the inventors of the present application find that the above-mentioned technology has at least the following technical problems:

the starch and other components are directly blended by a dry method, and due to incompatibility between the hydrophilic surface of the starch and EVA, the interface bonding force of two phases of the blend is weak, so that the phase separation phenomenon can occur when the starch and the EVA are blended, and further, the reaction time is too short, the starch grafting rate is low, and the blending effect is poor.

Disclosure of Invention

The embodiment of the application provides a preparation method of biodegradable foamed sole, solves the problem of incompatibility between starch hydrophilic surface and EVA in the prior art, increases the bonding force of the blending interface of starch and EVA, reduces the interface gap, further improves the comprehensive performance of the blend, improves the performance of sole material, has biodegradability, and can relieve the environmental problem caused by white pollution.

The embodiment of the application provides a preparation method of a biodegradable foamed sole, which specifically comprises the following steps:

(a) crushing the waste EVA material to obtain a crushed material;

(b) 75 parts of crushed materials, 3 parts of mineral oil and 5 parts of EVA7870S 5 are subjected to banburying and open milling and then are calendered into a recycled EVA film with the thickness of 0.01mm-0.05 mm;

(c) preparing biodegradable material rice, wherein the biodegradable material rice is prepared from the following components in parts by weight:

firstly, mixing the raw materials except the crosslinking agent BIBP and the foaming agent AC, banburying, adjusting the banburying temperature to 88-93 ℃, keeping for 4 minutes and then stirring; when the banburying temperature is increased to 97 ℃, turning materials for the second time; when the banburying temperature is increased to 103 ℃, turning for the third time, and adding a crosslinking agent BIBP and a foaming agent AC; when the banburying temperature is increased to 109 ℃, turning materials for the fourth time; carrying out fifth material turning when the banburying temperature is raised to 115 ℃, carrying out banburying for 1 minute, and finally carrying out material pouring, open milling and granulation to obtain biodegradable material rice;

(d) adding the biodegradable material into a machine, automatically sucking the material, and performing one-time injection molding at the gun temperature of 90-108 ℃, the mold temperature of 175-180 ℃ and the time of 170-200 seconds to obtain the foamed sole.

Further, the preparation method of the starch grafted EVA in the step (c) is that the starch is dissolved in water, heated to 93 ℃, gelatinized for 35min, then cooled to 55 ℃, added with ammonium persulfate initiator, added with EVA emulsion, heated to 85 ℃, reacted for 3-4 hours, added with absolute ethyl alcohol for precipitation, filtered and dried to obtain the starch grafted EVA.

Wherein, starch grafting EVA with starch grafting rate of 28% is preferred, and the preparation method comprises the following steps: dissolving 28g of corn starch in water, heating to 93 ℃, gelatinizing for 35min, cooling to 55 ℃, adding 1.2g of ammonium persulfate initiator, adding 131g of EVA emulsion (with the solid content of 55% (mass fraction), the VA content in EVA of 85% (mass fraction) and the viscosity of 4000 +/-500 cP), heating to 85 ℃, reacting for 3.6 hours, slowly adding absolute ethyl alcohol for precipitation, standing for 6 hours at room temperature, filtering and drying to obtain the starch grafted EVA with the starch grafting rate of 28%.

Further, the starch grafting proportion is 25-38%, namely, starch is grafted to EVA to obtain a product of starch grafted EVA, and the starch content of the starch grafted EVA is 25-38%.

Further, the waste EVA materials in the step (a) comprise scrap heads, defective products, waste products and leftover materials generated in the process of producing EVA shoe soles.

Furthermore, the broken material in the step (a) is strip-shaped broken material with the thickness of 1.3mm-3mm and the width of 2mm-5 mm.

Further, the thickness of the recovered EVA film in the step (a) is 0.01mm to 0.02 mm.

Further, in the step (c), the maleic anhydride-grafted POE is a product in which the maleic anhydride grafting ratio is 1.3%, and the maleic anhydride-grafted POE is a product in which the content of maleic anhydride is 1.3%.

Further, the biodegradable rice is cake-shaped, the thickness is 1.5mm-4mm, and the diameter is 4mm-8 mm.

Further, the waste EVA materials are crushed by a crusher, the crusher is of a double-roller semi-open type, the distance between a front roller and a rear roller is 1mm-4mm, the speed ratio of the front roller to the rear roller is 1:1-2, and the roller temperature is 0-50 ℃.

One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

1. the starch grafted EVA is adopted, so that the interfacial adhesion of the starch and the EVA blend can be enhanced, and the interfacial gap is reduced, so that the comprehensive performance of the blend is improved, the phase separation generated in the blending of the starch and the EVA is avoided, meanwhile, the starch grafted EVA is environment-friendly and biodegradable, and the sole prepared by the method is easy to decompose and metabolize by enzymes in various microorganisms or animals and plants in the nature, is a typical biodegradable polymer material, and the residues exist in dispersed small particles of powder, so that the problem of environmental pollution caused by waste shoes is greatly relieved.

2. The invention takes the recycled EVA film and the starch grafted EVA as main systems, utilizes the EVA to adjust foaming and crosslinking performances, utilizes the terminal carboxyl of the maleic anhydride grafted POE and the terminal hydroxyl of the starch grafted EVA to easily generate chemical reaction, enhances the binding force, and obtains the biodegradable foamed sole which has the characteristics of light weight, high elasticity, low cost and the like.

3. According to the invention, the recycled EVA film is obtained by crushing, banburying and rolling the scrap heads, defective products, waste products and leftover materials in the production process of the EVA sole by a crusher according to weight, so that solid insoluble substances such as sand, metal, glass and the like can be well removed, the high-value recycling of EVA waste is realized, and the waste materials generated in the production process of the EVA sole are effectively reduced. Meanwhile, the experimental data of the embodiment and the comparative example show that the performance of the recycled EVA film is obviously better than that of the EVA recycled powder, and compared with the commercially available EVA sole material, the recycled EVA film has the performance close to or even better than that of the commercially available EVA sole material, so that the high-value recycling of EVA is realized, the EVA utilization rate is improved, the raw material cost is reduced, and the recycled EVA film is more environment-friendly.

Detailed Description

The invention will now be further illustrated with reference to specific examples.

The following are a summary of the raw material compositions of the examples and comparative examples, resulting in table 1:

TABLE 1 summary of the raw material compositions of the examples and comparative examples