Thermal Stabilizers Shift to Environment-Friendly
Year:2007 ISSUE:36
COLUMN:MARKET REPORT
Click:349    DateTime:Dec.25,2007
Thermal Stabilizers Shift to Environment-Friendly    

By Shi Xunruo, Hangzhou Xinxin Plastic Auxiliaries Research Co., Ltd.  

Environmental protection regulations are getting stricter and traditional thermal (heat) stabilizers have a dim future

Lead salt stabilizers are the effective varieties developed earliest. Owing to their low price, they have always occupied the majority of the PVC thermal stabilizer market. Lead compounds are typical toxic. Cadmium salt stabilizers are extensively used in transparent plastic products. Cadmium has great toxicity and long-time contact or entrance into human bodies through various channels may seriously endanger human health.
   To protect the living environment and improve the life quality of mankind, various countries in the world have prohibited the use of lead salt and cadmium salt stabilizers since the 1980s. China has formulated national standards defining the limits for contents of lead, cadmium and other toxic substances in PVC products used in the packaging of medical apparatuses and foods. To get linked to the international market, various ministries and commissions of China have since 2003 started to consider taking lead prohibition measures. To cope with WEEE and RoHS of the European Union, seven ministries and commissions of China issued the Methods for the Pollution Control on Electronic Information Products on February 28th, 2006, laying down provisions for toxic substances such as lead and cadmium similar to RoHS. The document already started implementation from March 1st, 2007.

The output is growing further and high-end products have a bright market prospect

The capacity of thermal stabilizers in China reached more than 400 000 t/a in 2006. There were more than 300 producers. More than 100 varieties were produced and 60 of them were general purpose varieties. Major varieties include lead salt varieties (accounting for around 40% of the total output), stearic salt varieties (20%), compound metal soap varieties (24%), organic tin varieties (6%) and rare earth and organic auxiliary varieties (10%).
   The development of environment-friendly thermal stabilizers in China has made great progress. Several key large producers are doing their utmost to catch up. Wenzhou Tianshen Plastic Auxiliary Co., Ltd. organized technicians to conduct the R&D of calcium/zinc compound varieties several years ago and some commercialized products have been put into market. Hebei Jingxin Chemical Group and Nanjing Jinling Chemical Factory have used joint venture with foreign companies to construct large units with a capacity of over 10 000 t/a. Shenzhen AIMSEA Industrial Co., Ltd and Hangzhou Sanye Auxiliary Co., Ltd. have used their own R&D teams and achieved satisfactory results in the development of powder, paste and liquid calcium/zinc and rare earth compound varieties. Besides, universities and research institutes such as Beijing Research Institute of Chemical Industry, Shanxi Additive Research Institute of Chemical Industry, Beijing Additive Research Institute and Jiangsu Research Institute of Daily Chemistry have also done a lot of work on the R&D and production of calcium/zinc compound stabilizers, rare earth/calcium compound stabilizers and calcium/zinc product additives, beta-diketone and basic aluminum magnesium carbonate (hydrotalcite).
   An objective analysis to the status of thermal stabilizers in China today shows that if lead salt and cadmium salt products are not considered the environment-friendly thermal stabilizers have already formed a system based on organic tin varieties (including compound varieties), calcium/zinc compound varieties and rare earth compound varieties. In terms of product output and user acceptance, calcium/zinc compound varieties still hold the first place.


Output of Thermal Stabilizers in China in Recent Year (thousand tons)
Variety     1995    2000    2005    2006 (estimated)
Lead salt varieties       18.9    60.9    84.0    120.0
Cadmium salt varieties    20.1    27.6    31.5    60.0
Compound varieties      5.1     29.0    50.4    72.0
Organic tin varieties    2.5     7.3     23.1    18.0
Rare earth and other varieties    3.3     20.3    21.0    30.0
Total output            49.9    145.1    210.0    300.0
Source: Plastic Industry Yearbook