On November 17th, Jinan, Shandong Province experienced continuous rains and chills. At the working meeting of the expert group of the 16th member representative assembly of the Comprehensive Rubber Utilization Subcommittee of the China Rubber Industry Association, experts held a heated discussion around the revision of the 2008 national standard for recycled rubber. Experts from companies, associations, and scientific research institutes agreed that it is necessary to revise the standards and proposed to accelerate the elimination of coal tar softeners and increase the detection of harmful substances such as polycyclic aromatic hydrocarbons.

Cao Qingxin, Secretary-General of the Waste Rubber Comprehensive Utilization Branch of the China Rubber Industry Association, told reporters that in October this year, the European Tire and Rubber Manufacturers Association announced the second batch of spot checks on the content of polycyclic aromatic hydrocarbons in the European Union market. A total of nine brands were detected. Ten tires exceeded the limit, of which nine were produced in China. In the previous batch of spot checks announced, there were also 12 unqualified tires originating in China. Recently, the European Tire and Rubber Manufacturers Association once again urged the EU and its member countries to increase the regulation and enforcement of PAH limits in tires. This has made the situation of China's tire exports to the EU become more serious.

Therefore, as a recycled rubber that is one of the raw materials for rubber products such as tires, the content of PAHs harmful substances affects the industry's nerves, and also promoted the start of the revision process of the national standard.

Experts said that in recent years, the rising prices of natural rubber and synthetic rubber materials have made the proportion of recycled rubber used in the rubber products industry gradually increasing. At the same time, as environmental protection requirements for rubber products at home and abroad have become increasingly stringent, the development of environment-friendly recycled rubber is imperative. The elimination of coal tar softeners is a real problem that the reclaimed rubber industry has to face. The start of the revision of the national standard is centered on the environmental problems existing in the use of coal tar in the current production process of recycled rubber, and may increase the number of harmful substances such as polycyclic aromatic hydrocarbons. Test items.

The reporter learned that, according to the detection of reclaimed rubber produced from coal tar as a softener, its PAH content was as high as 8876.8 mg/kg, and its PAH content (8 items) was as high as 638.1 mg/kg, far exceeding. The relevant laws and regulations in developed countries such as Europe and the United States are toxic and hazardous pollution-free recycled rubber. Rubber products containing such reclaimed rubber are naturally difficult to pass through in the export inspection. The use of pine tar oil, saponin oil, rapeseed oil and other plant series produced 18 kinds of recycled rubber polycyclic aromatic hydrocarbons measured in 31.2 mg / kg, polycyclic aromatic hydrocarbon content (8 items) in the 32 mg / kg or so, in line with European and American environmental protection Testing standards.

During this period, experts in the modification of national standards to increase the detection of harmful substances such as polycyclic aromatic hydrocarbons focused on the limits of the indicators. Xiao Pingzhong, general manager of Shanghai Xiaoyou Rubber Co., Ltd. and Zhang Yanbin, general manager of Jiangxi Guoyan High-tech Materials Technology Co., Ltd. believe that during the production and use of recycled rubber produced from coal tar, a large amount of toxic substances is emitted into the atmosphere. Therefore, in the newly revised national standard, environmental protection indicators should be aligned with those of Europe and the United States, and the use of coal tar should be stopped.

Some members of the expert group also pointed out that since the production of recycled rubber has been in China for many years, although it has undergone various reforms in production processes, most of the domestic reclaimed rubber companies have not used the softeners in the production process. Tar out of the tar, so it should give renewable rubber production companies a transition time, and gradually eliminate them, to meet environmental protection requirements.

"The use of coal tar as a softener will enable the reclaimed rubber to have good elongation and strength. If it is replaced with a plant series, will it reduce such physical properties? Should the physical properties of reclaimed rubber be reduced in the national standard? As the cost increases, whether the downstream product industry can accept it should be seriously considered.” Some experts said without hesitation.

“Despite the fact that prices of biological and plant series softeners are higher than coal tar prices, despite the fact that environmental-friendly recycled rubber production costs are higher than the cost of polluted recycled rubber, the elimination of coal tar is the need for long-term development of enterprises under the pressure of environmental protection at home and abroad. The need for industrial upgrading is a general trend, said Cao Qingxin.

Dong Min, deputy director of the Tianjin Rubber Industry Research Institute, told reporters that under the pressure of environmental protection, the elimination of coal tar in the production of recycled rubber is an inevitable trend. It is recommended that companies pay attention to adjusting the use plan of coal tar softeners and seek alternative types of softeners. And resources. Cao Qingxin also expressed the hope that the revised national standard will serve as a mandatory standard and raise the industry's threshold.

It is understood that as the key unit of China's rubber industry's reclaimed rubber technology, the Tianjin Rubber Industry Research Institute will take the lead in the revision of the national standard. After discussing with representatives of reclaimed rubber production enterprises and downstream product companies in the near future, the 2008 edition of the national standard will be drafted and revised. Approval by the National Standardization Management Committee requires a maximum of one year.

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