BR-102024017436-A2 - Reincorporation of EVA waste into the production of footwear materials.

BR102024017436A2BR 102024017436 A2BR102024017436 A2BR 102024017436A2BR-102024017436-A2

Abstract

This invention proposes an innovative process for the production of polymer composites reinforced with EVA (ethylene-vinyl acetate) waste, specifically aimed at the footwear sector. The objective is to efficiently reincorporate EVA waste generated by the industry, taking advantage of its intrinsic properties to improve the characteristics of the final products. The innovation of this work lies in the ability to integrate EVA waste into the polymer matrix, resulting in composites with enhanced mechanical and durability properties. The process involves preparing a polymer mixture with different percentages of EVA waste, which is shaped to create materials that combine lightness, strength, and stability. These composites are ideal for applications requiring high resistance to degradation and excellent mechanical performance, fundamental characteristics for the manufacture of high-quality footwear. By promoting the efficient recycling of EVA waste, this process not only contributes to environmental sustainability but also offers a viable and economical technical solution for the footwear industry, aligning with the growing demands for more sustainable production practices.

Inventors

LUCAS CORDEIRO DE OLIVEIRA
TAYNAH PEREIRA GALDINO
ANTONIO BRAZ DE MEDEIROS BISNETO
RAQUEL ALBINO DE JESUS
WLADYMYR JEFFERSON BACALHAU DE SOUSA
MARCUS VINICIUS LIA FOOK
SUÉDINA MARIA DE LIMA SILVA

Assignees

Universidade Federal De Campina Grande - Pb

Dates

Publication Date: 20260310
Application Date: 20240824

Claims (8)

1. PROCESS FOR RECYCLING AND REUSING EVA WASTE TO OBTAIN COMPOSITE MATERIALS, characterized by an invention that corresponds to the incorporation of EVA waste into a polymeric matrix, comprising: shredding the EVA waste, mixing with additives and polymers, compression or extrusion molding, and thermal curing.
2. PROCESS FOR RECYCLING AND REUSING EVA WASTE TO OBTAIN COMPOSITE MATERIALS, according to claim 1, characterized in that the crosslinking availability content of the EVA waste is between 20% and 55% by weight in the mixture.
3. PROCESS FOR RECYCLING AND REUSING EVA WASTE TO OBTAIN COMPOSITE MATERIALS, according to claim 1, characterized by the use of compatibilizing additives that improve the adhesion between the EVA waste and the polymer matrix.
4. PROCESS FOR RECYCLING AND REUSING EVA WASTE TO OBTAIN COMPOSITE MATERIALS, according to claim 1, characterized in that the molding step is carried out at temperatures between 150°C and 200°C.
5. PROCESS FOR RECYCLING AND REUSING EVA WASTE TO OBTAIN COMPOSITE MATERIALS, according to claim 1, characterized by the final product exhibiting resistance to hydrolysis, according to the tests performed.
6. PROCESS FOR RECYCLING AND REUSING EVA WASTE TO OBTAIN COMPOSITE MATERIALS, according to claim 1, characterized by the final product having specific properties, such as density, Asker C hardness and compressive strength superior to the reference sample that did not contain waste.
7. PROCESS FOR RECYCLING AND REUSING EVA WASTE TO OBTAIN COMPOSITE MATERIALS, according to claim 1, characterized by the use of scanning electron microscopy (SEM) and X-ray fluorescence analyses to evaluate the morphology and chemical composition of the final material.
8. PROCESS FOR RECYCLING AND REUSING EVA WASTE TO OBTAIN COMPOSITE MATERIALS, characterized by the increase in cross-linking in the samples, according to the previous claims, characterized by the fact that, as the presence of EVA waste increases, there is a significant increase in cross-linking within the composite, as evidenced by the results of Fourier transform infrared spectroscopy (FTIR) which show an increase in the vibration band associated with the vinyl acetate group.

Description

Field of invention [001] The present invention relates to a method for producing materials for the footwear industry using recycled EVA (ethylene-vinyl acetate) waste. More specifically, it is an innovative process that involves the reuse of EVA waste for the manufacture of shoe soles and insoles, with an emphasis on improving the physical and thermal properties of the recycled material. The proposed method encompasses steps of particle size selection, physical modification, and processing of EVA waste, resulting in a high-quality recycled polymeric material suitable for the production of soles and other footwear components. The invention applies to the field of recycled polymeric materials, focusing on sustainability and efficiency in industrial production, especially in the footwear sector, offering a solution that combines environmental responsibility with improved functional properties of the final products. Background of the invention [002] The footwear industry has stood out as one of the main consumer sectors of polymeric materials, especially EVA (ethylene-vinyl acetate), widely used in the production of soles and insoles. This copolymer is valued for its physical properties, such as lightness, flexibility, and impact resistance. However, the disposal of EVA waste during the production process has become a significant environmental concern. The growing demand for sustainable solutions in the industry has highlighted the need for alternatives that minimize the environmental impact associated with the disposal of polymeric materials. [003] Several studies have explored the incorporation of industrial EVA waste into new products, aiming at both sustainability and material savings. EVA recycling is a widely discussed topic, with research focused on the reuse of this waste in different sectors, such as construction and the manufacture of consumer products. However, the reuse of EVA in the footwear industry itself still faces challenges, especially regarding the maintenance or improvement of the physical and thermal properties of the resulting products. [004] Innovation in the treatment of EVA waste for reintegration into production processes is an area of growing interest. Techniques such as particle size selection and chemical modification of recycled EVA have been studied to improve its properties and expand its applications. However, there is still a significant gap in the development of methods that ensure not only efficient recycling, but also the improvement of the final properties of the material, such as wear resistance, thermal insulation and flexibility, crucial characteristics for footwear products. [005] In this context, the development of methods that allow the recycling of EVA with improvements in physical and thermal properties presents great innovative potential. The present invention proposes a method that directly addresses these issues, offering a technical solution for the efficient reuse of EVA waste, while improving the properties of the recycled material, making it suitable for the production of high-quality footwear. [006] Brazilian patent BR 102013016644-8 A2, entitled “Improvement introduced in the recycling process of ethylene vinyl acetate - EVA - and resulting product” describes an EVA recycling process focused on improving the quality of the recycled material. The central difference in relation to our patent application lies in the fact that our process involves the controlled increase of cross-links in the material matrix, using EVA waste to obtain a composite with superior mechanical and thermal properties. Furthermore, the characterization techniques applied in our work, such as FTIR, to monitor the increase in cross-links, are not addressed in the aforementioned patent. [007] In Brazilian patent BR 102019004172-2 A2, titled “Groofing mortar, use of grouting mortar and use of EVA waste,” the focus is on the use of EVA waste in grouting mortar to improve its flexibility and crack resistance. This invention differs from our approach because the described method is limited to the application of EVA in a specific construction product. Our patent, on the other hand, involves the incorporation of EVA waste into a composite, with an emphasis on structural modification through increased cross-linking, resulting in a material with enhanced properties for multiple applications in the footwear industry. Furthermore, the exact processing conditions of the waste and the formation of new bonds are not specified in the patent. [008] Brazilian patent PI 0505243-2 A, entitled “EVA waste-based composite material”, deals with the creation of a composite using EVA waste, but does not detail the process of structural modification of the material. Our work differs by specifically describing the increase in cross-links in the material matrix, resulting in significant improvements in the mechanical and thermal properties of the composite. The aforementioned patent also does not address the contr