 Their increasing popularity stems from a combination of factors, including their thermal properties, their light weight, and their natural hypoallergenic properties.The opening of the Chinese market to the world since the 1990s has also played a significant role in the spread of silk comforters, as China is both the world's biggest silk producer and silk comforter manufacturer.Silk comes from the cocoons of the silkworm, which feeds off mulberry trees in subtropical climates.