Once, they were made entirely of natural rubber.

以往，轮胎完全由天然橡胶制成。

Until recently, sneakers used natural rubber for this process.

很长时间以来，在这个过程中，运动鞋的制作都使用天然橡胶。

Plastic vegan belts and shoes made from tree bark or natural rubber labelled vegan.

塑料皮带，以及由树皮或天然橡胶制成的鞋子都被标记为“纯”产品。

But today, most outer soles are made with a synthetic blend of natural rubber and byproducts from coal and oil.

但如今，大多数外底材料由天然橡胶和煤及石油的副产品混合而成。

It is usually cheaper than natural rubber.

它通常比天然橡胶便宜。

Some of that will be natural rubber obtained from the sap of rubber trees.

其中一从橡胶树的汁液中提取的天然橡胶。

People get natural rubber from rubber trees as a white, milky liquid, which is called latex.

人们从橡胶树上获取天然橡胶，呈白色乳状液体，称为乳胶。

Today, the world needs so much rubber that we use both natural and artificial rubber in large amounts.

今天，世界需要如此多的橡胶，以至于我们大量使用天然橡胶和人造橡胶。

The company makes these from latex, a mixture of water and natural rubber tapped from the bark of rubber trees.

该公司用乳胶制成这产品，乳胶水和从橡胶树皮中取出的天然橡胶的混合物。

The Cranfield team are working with Levidian and others to produce graphene-infused natural rubber aerospace balloons to operate at altitudes of 30km.

克兰菲尔德团队正在与Levidian和其他人合作，生产注入石墨烯的天然橡胶航空航天气球，以在30公里的高度运行。

They are more sustainable than nitrile gloves because natural rubber absorbs carbon dioxide rather than producing it, and they should biodegrade in about a year.

它们比丁腈手套更具可持续性， 因为天然橡胶吸收二氧化碳而不产生二氧化碳，并且它们应该在大约一年内生物降解。