the People's Republic of China national standards

Bleached shellac (Bleached lac) GB 8140-1987

This standard is applicable to bleached shellac and refined bleached shellac.

This standard refers to the international standard ISO 57-1975 Bleached Lac.

1 Definition

Bleached shellac refers to light-colored shellac made of shellac or granular shellac as raw material, dissolved in sodium carbonate solution or other weak alkali solution, removed impurities or shellac wax, and bleached with bleaching agent; wax-containing bleached shellac is ordinary bleached shellac; Dewaxed bleached shellac is refined bleached shellac.

2 Technical requirements

Bleached shellac technical indicators are as follows

Note: ① Storage period: Grade I is one year, Grade II is eight months.

The product is not allowed to contain rosin and other adulterants.

③ The iodine value and saponification value shall be agreed upon by both parties if necessary.

All the indexes in bleached lac are the results of absolute dry sample calculation.

3 Other provisions

3.1 this standard product from the date of production, grade I products within one year, grade II products within 8 months if it has become insoluble in alcohol, the buyer can return or compensation.

3.2 Other provisions of this standard shall be in accordance with GB 8138-87 Purple Film.

4 Packaging, transportation and storage

4.1 bleached shellac is packed in wooden cases or other packaging, lined with a layer of kraft paper. The net weight of each box is 25kg. The factory, product name, grade and production date are marked on the box, and the words "sun protection" and "moisture protection" are marked. The product inspection certificate is placed in the box.

The storage and transportation time of 4.2 products should be reduced as much as possible, and the sun, rain and near heat sources and humid places are strictly prohibited during transportation.

4.3 products are stored in a dry, ventilated and cool room to prevent caking.

5 Product inspection

The technical indexes of bleached shellac shall be carried out according to GB 8143-87 "Inspection Method for Shellac Products.

Additional Notes:

This standard is under the centralized management of the Institute of Forest Products Chemical Industry, Chinese Academy of Forestry.

This standard was drafted by the Institute of Forest Chemical Industry, Chinese Academy of Forestry.

The main draftsmen of this standard are Wu Tongfang, Yang Luan, Ma Wanqing and Wei Chakuan.