The moisture content of paper clay is higher than 20%, and microorganisms such as chromotropic fungi multiply and grow in paper clay.

2. nutrients

The most suitable nutrients needed by fungi in various objects are different, but all fungi can get the required nutrients from objects. Paper clay contains nutrients needed by fungi, so it will be moldy.

3. Temperature

Microorganisms can only grow in a certain temperature range, and the most suitable temperature for fungi growth is 20 ~ 30℃, while the temperature of paper clay may just reach this level, so it will be moldy.

Characteristics of paper clay:

1, various colors, non-toxic, non-sticky, good flexibility and strong plasticity.

2, the work does not need to be baked, naturally air-dried, and there will be no cracks after drying.

3. The work can be colored after drying and setting (it can be colored with watercolor or advertising color), and can be colored with watercolor, oil painting pigment, acrylic pigment, nail polish, etc. , very inclusive. When the color dries, it can be preserved for a long time by varnish.

4, high adhesion with other materials, whether paper, glass, metal, lace, beads have excellent adhesion.

5. As paper clay will air-dry naturally when exposed to air, it will not dry as long as it is not exposed to air.

6. The drying speed depends on the size of the work. The smaller the work, the faster the drying speed, and the greater the drying speed. The surface drying time is generally about 3 hours.

7. Because paper clay, especially ultra-light soil, can obviously reflect the lines pressed on the material, many people apply it to the production of handprints, such as wedding couple handprints, baby growth handprints, etc., so it is also called hand-foot inkpad.