XXXV IULTCS CONGRESS 2019
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Session 7 (Friday)

Session chair: Poncet, Thierry, (CTC - Centre Technique Cuir, Cholet, France); Yoshimura, Keiji, Dr (Japan Leather and Leather Goods Industries Association, Tokyo, Japan)
 
Shortcut: S7
Date: Friday, 28 June, 2019, 9:20 AM – 10:20 AM
Room: Hall 1/2
Session type: Oral

Contents

Click on an contribution to preview the abstract content.

9:20 AM S7-01

Sustainable Value Creation from Leather Solid Wastes: Preparation of Shoe Soling Material using Nano Fillers (#26)

S. Gupta3, S. Ponsubbiah2, S. K. Gupta1, S. Mandal3

1 Shiv Nadar University, School of Management and Entrepreneurship , Gautam Buddha Nagar, India
2 Institute of Leather Technology, Chennai, India
3 Central Leather Research Institute, Chennai, India

Content

This research aims at recycling of the leather industry solid waste, chrome shaving, into shoe components, such as outsole and insole material. Chrome shaving waste from the leather industry was used for making shoe soles by mixing with rubber and inorganic nanoparticles. Isoprene and Ethylene propylene monomer (EPDM) rubbers were used for this purpose. Various combinations of rubber, nanoparticle and chrome shaving waste were studied to get the desired characteristics of soling material. The prepared shoe soles were characterized for physico-mechanical behaviours like hardness, density, abrasion resistance and tensile strength, and compared with those of the rubber-based soling material available commercially. The shoe sole prepared using a combination of the isoprene and EPDM (1:1) rubber along with chrome shaving waste and kaolinite/silica nanoparticles showed physico-mechanical characteristics very close to the commercial soling material with higher value of percentage elongation. Hence, an efficient use of the fibrous chrome shaving and trimming wastes from leather industry in sole making would avoid the environmental problem, and could be a source of sustainable value-creation.

Take-Away

1. Ethylene propylene monomer rubber and leather fibre with inorganic nano clay based fillers, the composites are well in terms of all the physic-mechanical behaviours like hardness, density, abrasion resistance and grain crack suitable for shoe sole application.

2. An efficient way of utilization of these fibrous waste materials may be to combine them in a suitable form with synthetic polymers to give composite materials. Short fiber reinforcement of polymers is an important area in polymer composites where both synthetic and natural fibers are effectively used.

Keywords: Recycling, Leather, Solid waste, Shoe sole
9:35 AM S7-02

Extended Surfactants for Leather (#218)

A. Kilikli1, I. Reetz1

1 Pulcra Chemicals GmbH, Geretsried, Germany

Content

Surfactants of different ionic nature are used in virtually all steps of leather production. In processes like soaking, degreasing and wool washing, tremendous amounts of surfactants are applied and to a great extent discharged into the tannery effluent. In order to improve the sustainability of leather processing, there is a constant search for more efficient, environmentally friendly emulsifiers, which give superior results already in smaller usage amounts.

By introduction of propylene oxide based lipophilic linkers between the hydrophilic head and hydrophobic tail, the wetting and emulsion capability of a surfactant can be increased significantly. The resulting surfactants, so called extended surfactants, are generally more hydrophobic and have an extended tail, which reaches further into the oil face without scarifying the water solubility, what would be the results when increasing the alkyl chain. Thus, the use of lipophilic linker changes the emulsion on a structural level. Extended surfactants have been found to be superior in various applications, including textile laundry or tertiary oil recovery.

In the present work, the efficiency of various types of non-ionic and anionic extended surfactants is demonstrated in various stages of leather making. Model surfactants with lipophilic linkers are compared to their analogues without linker molecules. In many processes, significantly improved surfactant efficiencies are found making this group of molecules an interesting topic for further exploitation.

Take-Away

Significantly improved surfactant efficiency for more sustainable leather processing

Keywords: extended surfactant, degreasing, wool washing
9:50 AM S7-03

Factors affecting penetration of acrylic resin in crust leather during retanning process (#179)

Y. Song1, Y. Zeng1, M. Cao2, B. Shi1, 2

1 Sichuan University, National Engineering Laboratory for Clean Technology of Leather Manufacture, Chengdu, China
2 Ministry of Education, Key Laboratory of Leather Chemistry and Engineering (Sichuan University), Chengdu, China

Content

Acrylic resin (AR) is a most popular retanning agent due to its selective filling property and advantage of formaldehyde-free. The retanning performance of acrylic resin mainly depends on its penetration depth and filling parts in leather. Therefore, to improve the retanning performance, it is necessary to fully understand the factors affecting the mass transfer and the distribution of acrylic resin in leather. We have found that the structure and the charge of leather and the dosage of acrylic resin rather than the molecular weight of acrylic resin are important factors affecting the penetration rate of acrylic resin in crust leather by using fluorescent tracer technique. In this study, from the view of electrostatic interaction, effects of neutralizing pH and retanning auxiliaries such as phenol sulfonic acid condensation (PSAC) and sodium carboxymethylcellulose (CMC) on the penetration and the distribution of acrylic resin in crust leather were investigated. Higher neutralizing pH led to a faster transfer of acrylic resin in leather because of the decrease in the positive charges of chrome-tanned leather (isoelectric point 7.1) and the increase in the negative charges of acrylic resin. Employing PSAC and CMC enhanced acrylic resin transfer in crust leather due to the dramatic increase in the negative charges of acrylic resin. These results indicated that decreasing the electrostatic binding force between acrylic resin and crust leather is beneficial to the penetration of acrylic resin in leather, which could be achieved by adjusting the neutralizing pH or using acrylic resin together with proper retanning auxiliaries.

Take-Away

1. Using phenol sulfonic acid condensation and sodium carboxymethylcellulose enhanced acrylic resin transfer in crust leather.

2. Decreasing electrostatic binding force between acrylic resin and crust leather is beneficial to penetration of acrylic resin in leather.

3. Increasing neutralizing pH or using proper retanning auxiliaries can decrease the electrostatic interaction between acrylic resin and crust leather effectively.

Fig. 1. Schematic diagram of penetration of acrylic resin in crust leather during retanning process.
Fig. 2. Fluorescence micrographs of vertical sections from the leathers retanned for 90 min at 35℃.
Keywords: retanning, acrylic resin, penetration, electrostatic interaction
10:05 AM S7-04

BIOPOLYMER-LIPOSOME COMPOSITE FOR FATLIQUOR APPLICATIONS- A ‘GREEN’ APPROACH TO OPTIMAL TRANSPORT AND DELIVERY OF NATURAL OILS (#279)

N. Bhargavi1, D. Aruna2, K. J. Sreeram1

1 CSIR-CENTRAL LEATHER RESEARCH INSTITUTE, CATERS Division, CHENNAI, India
2 CSIR-CENTRAL LEATHER RESEARCH INSTITUTE, ADVANCED MATERIALS LABORATORY, CHENNAI, India

Content

The wastewater after the fatliquoring process contains the surfactants, neutral salts and unspent or unbound oil. This is predominantly attributed to the manner in which fatliquors are prepared. The oil in water emulsions (fatliquors) are prepared through chemical modification of oils along with surface active agents that would enhance the dispersion of oil in water. The discharged chemical compounds from the post tanning process are likely to exist as persistent organics in the soil.

                        In this paper, an ambitious effort to take forward the successful lessons from other sectors such as healthcare is presented. The use of liposomes as oil carriers has been envisaged. For this, the lacunae associated with liposomal carriers such as stability, encapsulation efficiency, the release of payload under desired conditions etc. has been addressed. The study focuses on stabilizing the liposomes and the triggered delivery under the drum pH conditions. A liposomes -biopolymer composite based on Egg Phosphatidyl Choline and Pectin encapsulating oil, has been prepared. Using spectroscopic and colorimetric techniques the presence of biopolymer in the composite, encapsulation of oil and stability over a range of pH conditions has been investigated. The biopolymer influences the stability and oil encapsulation efficiency of the composite in a concentration-dependent manner. To understand the release of oil in a pH dependent manner, the oil was substituted with a model dye and its release under a narrow pH span was observed, indicating that the oil could be released to fibers by modulating the pH. Initial studies relating to the potential of this product as a possible fatliquor is encouraging.

Take-Away

  • A stabilized liposomal systems encapsulating oil as a delivery vehicle to deliver its contents under the triggered pH conditions is described.
  • Biopolymer, induced  stability and ensures the oil encapsulation in the bilayer region for the composite vesicles.
  • The work initiates a step towards developing fatliquors based on biodegradable materials, avoiding the emulsifiers and conventional route to make oil in water emulsions.
Keywords: Fatliquors, Biopolymers, Liposomes, Composite vesicles