LCA

Outer layer

Fig.3. Eco-costs/ carbon footprint in lifecycle of Outer Layers (old design)

Nylon and polyurethane are spined and weaved together to confirm the stretchability and toughness simultaneously. Polymerization process takes vast amounts of energy and discharge a large amount of wastewater containing nitrogen oxides, sulfur oxides, and small molecule organic solvents^[6]. The raw materials are produced in China (15000km) and Mexico (3000km) and delivered to US for Gore-Tex film installation. Then the products need to be transport to China again to occupying the rising market, leading to higher (almost doubled) eco-cost and carbon footprint. The only step that consumes energy during use may be washing, which will consume electrical energy.

It is a little difficult for disposal of the trousers. The only way to reuse PU fiber would be co-fired in electrical power plant because it is highly swelled^[7], worn, and toxic which makes it hard to reuse like nylon. And PE film, a source of white pollution, is also hard to recycle and needs to be incinerated. Only nylon is possible to be recycled and reused after chemical treatment. Therefore, the eco-cost and carbon footprint become higher.

Inner layer

Fig.4. Eco-costs/ carbon footprint in lifecycle of Inner Layers (old design)

The raw material used to make the inner layer of ski pants is mainly wool. It is obtained by breeding sheep and then shaving them, which creates a lot of carbon dioxide and biowaste during the breeding process[8]. Because it is a natural material, the manufacturing process is relatively simple, spinning and weaving, the raw material originates from China, the production place is the United States, mainly by plane (17000km), train (3000km), truck (300km) and other transportation methods. In terms of product use, wool requires special care and cleaning methods, usually hand-washing or dry-cleaning, which consumes electricity and causes sewage. At the same time, wool is easily damaged during use and washing, shortening the service life of it[8]. As for recycling, wool is generally difficult to recycle after multiple uses, resulting in significant eco-costs and carbon emissions. Its rough LCA flow diagram is shown in the Fig.5.

Fig.5. Streamlined life cycle of ski trousers (old product)

Streamlined LCA matrix and target plot

According to the result of LCA, Material stage and Disposal stage are weak points in ski trousers' life cycle. The high eco cost of wool and the industrial production process of polyurethane indicating urgent need for improvement or avoidance (Tab.1).

Table.1. A streamlined LCA matrix for old product Fig.6. A streamlined LCA target plot for old product

Environment Friendly Ski Trousers Design

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