Brief introduction of tire retreading industry

China is a big rubber consumer in the world. With the rapid development of automobile industry and mining machinery, China has become the largest rubber consumer in the world for seven consecutive years. According to the statistics of the World Rubber Research Organization, the consumption of china rubber in 2008 was 5.995 million tons, accounting for 27% of the world's total consumption. At the same time, China is a country with very scarce rubber resources. More than 70% of natural rubber and 40% of synthetic rubber in China depend on imports, and the contradiction between supply and demand is very prominent. In 2008, the domestic output of various tires was about 546 million (including motorcycle tires, etc.). ), the amount of waste tires is nearly 200 million.

As we all know, the world tire retreading industry has been established for more than a century. The history of tire retreading industry in China can be traced back to the tire retreading agency which appeared in 1928. Even though the first tire retreading factory in China was established from 1937, it has a history of 72 years. Since the founding of New China 60 years ago, the tire retreading industry in China has undergone earth-shaking changes. During the five years from 2004 to 2008, the domestic output of new tires was 239 million, 3. 1 .80 million, 433 million, 479 million and 555 million respectively (five-year growth1times). Due to the serious shortage of natural rubber and synthetic rubber resources, it has also promoted the rapid development of tire retreading industry. The retreading volume of used tires has increased year by year, from 9.6 million in 2004 to10000 in 2006, to1100000 in 2007, to120000 in 2008 and to10000 in 2009. China tire retreading industry began to step into the ranks of tire retreading producers in the world. Although the tire retreading industry in China has developed rapidly, the variety of retreaded tires is not wide enough, and more than 80% of them are concentrated in the tire retreading of buses and freight trucks. Others, such as: the renovation of car tires has just started, the renovation rate of large mining tires is only 20%, and the renovation rate of aviation tires is only about 10%. According to the statistics of 54 domestic enterprises above designated size by the National Bureau of Statistics in 2008, the total output value of tire retreading industry was 2.23 billion yuan; According to the statistics of 209 enterprises above designated size, the total industrial output value of reclaimed rubber production industry is 654.38+023 billion yuan. (1) The scale of the industry has expanded obviously. According to incomplete statistics, there are nearly 1,000 domestic tire retreading enterprises with an annual production capacity of about 20 million. There are more than 50 tire retreading enterprises with an annual output of more than 50,000 tires, 5 enterprises with an annual output of more than 50,000 tires/kloc-0, and the largest manufacturer with an annual output of more than 300,000 tires. There are also more than 0/000 reclaimed rubber and its supporting production enterprises/KLOC, with an annual production capacity of 3.5 million tons. There are more than one reclaimed rubber manufacturer with an annual output of 1 10,000 tons 100, more than one manufacturer with an annual output of 50,000 tons 10, and the largest manufacturer has an annual output of 654.38+10,000 tons; There are more than 200 rubber powder production enterprises with an annual production capacity of 6.5438+0 million tons; There are two ways to pyrolyze waste tires in China. One is standardized and scientific pyrolysis. Due to the large investment, the carbon black produced is of poor quality, difficult to sell and slow to develop. Its application ratio is less than 10%, and its annual output is about 50,000 tons. The other is that indigenous oil refining accounts for more than 90%, causing serious environmental pollution. Because of the small investment, quick recovery and large profits, although the state explicitly prohibits it, it has been repeatedly banned.

In 2009, 0/30,000 tires were refurbished, and the output of reclaimed rubber reached 2.45 million tons, but the output of rubber powder was less than 0/30,000 tons.

(2) The industrial layout shows a trend of cluster development, and private investment is dominant. Some large domestic tire retreading enterprises are mainly distributed in Guangdong, Shandong, Sichuan, Fujian, Jiangsu and other places, forming a diversified development pattern of state-owned, private and foreign capital, with private capital becoming the leading force; Reclaimed rubber production has formed reclaimed rubber production bases in Tangshan, Hebei, Nantong, Jiangsu, Pingyao, Shanxi, Wenzhou, Zhejiang, Jiaozuo, Henan, Maoming, Guangdong and Ya 'an, Sichuan. Form an industrial chain of recycling, dismantling, reuse and deep processing of waste tires.

(3) Breakthrough in key technologies. There are mainly the following aspects:

1. The key equipment for tire retreading, rubber powder and reclaimed rubber production has been mainly imported from the past to the present, and most of the products have been solved or reached the international level.

2. The tire retreading mode is changed from hot bias tire to pre-vulcanized cold radial tire.

3. The application of some modern inspection equipment makes the inspection of retreaded tires more scientific and reliable, thus ensuring the quality of products.

4. The additives of reclaimed rubber have changed from high pollutants to new alternative production capacity with less pollution, which has greatly improved tail gas control and energy consumption reduction.

5. Rubber powder desulfurization technology realizes dynamic, low temperature, normal pressure, continuous and net discharge.

6. The application of low-temperature micro-negative pressure catalytic cracking technology has turned black pollution into green energy, achieving the goals of continuity, low temperature, energy saving, emission reduction, high efficiency and environmental protection. During the "Tenth Five-Year Plan" and "Eleventh Five-Year Plan" periods, the state has given a series of policy support to the resource recycling and comprehensive utilization industries:

The Catalogue of Recycling Resources issued by the former State Economic and Trade Commission on June 5438+1October 10 in 2002 listed "waste tires" as products produced by recycling and comprehensive utilization of renewable resources;

On June 27th and July 2nd, 2005, the State Council successively issued the Notice of the State Council on Doing a Good Job in Building an Economical Society in the Near Future and Several Opinions of the State Council on Accelerating the Development of Circular Economy (Guo Fa [2005] No.21No.23), clearly pointing out that "waste tires" should be regarded as one of the key points of recycling and "recycling renewable resources well". It also calls for "persisting in promoting the development of circular economy according to law" and emphasizes "accelerating the research, establishment and improvement of circular economy laws and regulations system in light of China's national conditions";

In the Outline of the Eleventh Five-Year Plan for National Economic and Social Development, tire retreading and remanufacturing were included in the demonstration pilot of circular economy, and "saving resources and protecting the environment" was included in another basic national policy of our country.

In 2008, the Ministry of Finance of People's Republic of China (PRC) and State Taxation Administration of The People's Republic of China issued the Notice on Value-added Tax Policy for Products such as Comprehensive Utilization of Resources and the Notice on Value-added Tax Policy for Renewable Resources, namely 156 and 20081February 26th/005. 157, further strengthening the support for the real estate policy;

Article 40 of the Circular Economy Promotion Law, which came into effect on June 5438+1 October1,2009, stipulates that "the state supports enterprises to carry out remanufacturing of motor vehicle parts, construction machinery, machine tools and other products and tire retreading".

Under the guidance and support of a series of national industrial policies, it is widely known that waste tires are advocated for recycling as renewable resources, which also brings unprecedented development opportunities to the tire retreading and recycling industry. Great achievements have been made in the comprehensive utilization of waste tire resources in China: the renovation of waste tires has increased year by year, and the reclaimed rubber industry has flourished. The whole industry began to realize the transformation from traditional process methods and traditional concepts to new industrialization and clean production that is conducive to saving resources and protecting the environment; From simple recycling and pollution reduction to following ecological laws, clean production, recycling of resources and harmless treatment of waste. (1) The problems existing in retreading old tires are:

1, the state lacks mandatory technical quality standards for the retreading of new tires, and some new tires have quality problems during manufacturing and cannot meet the standards for retreading carcasses after use;

2. There is no mandatory wear limit detection requirement for tire use, users lack tire maintenance awareness, and overloaded vehicles are common, resulting in serious tread wear, crushed carcass and low turnover probability;

3. In order to reduce the investment cost, some tire retreading enterprises have a very low degree of automation of production equipment, and most of them use manual processing, so the product quality can not meet the standard. In addition, the frequent turnover events of fake tires have directly affected the image and reputation of retreaded tires.

(2) Main problems in reclaimed rubber production:

1, reclaimed rubber production enterprises are driven by interests, blindly developing and low-level redundant construction, resulting in overcapacity. The polarization phenomenon of reclaimed rubber production enterprises is prominent. The production scale of a group of backbone enterprises is over 10,000 tons, and the annual production capacity of the largest production enterprise reaches 654.38+10,000 tons, while the annual production capacity of small production enterprises is only about 1000 tons.

2. Some enterprises have backward production equipment and low technical level, which has caused certain pollution to the environment;

3. Reclaimed rubber production enterprises lack the support of fiscal and taxation policies, and reclaimed rubber production enterprises that meet the EIA standards cannot enjoy the preferential fiscal and taxation policies that tire retreading rubber powder production enterprises can enjoy.

(3) The internationally recognized reasons for the slow development of environment-friendly and resource-based rubber powder industry are:

1, there are some problems with equipment and technology;

2. Lack of development funds

3. The application and research of downstream products of rubber powder are lagging behind, which leads to poor market sales.

(four) the main problems existing in the cracking production of waste tires are:

1, there is no relevant inspection standard in China;

2. Adopt standardized and scientific cracking methods. Due to the large investment, the acquisition cost of waste tires is extremely high, and the quality of carbon black produced is poor, which leads to unfavorable sales and is difficult to popularize on a large scale;

3. The repeated prohibition of local oil refining has seriously polluted the environment and hit the confidence of investors.

To sum up, the best way to use waste tires is retreading. When the renovation times reach 1 1, the rubber and steel wire in the matrix can still be reused. At present, there are few enterprises with diversified industries in China.

Existing difficulties

The main problem of tire retreading is quality and safety. Excellent quality, there will be no security risks.

The main quality problems are: 1, the problems of the carcass itself, 2, poor repair technology, 3, poor quality of raw materials, 4, unstable curing temperature and pressure. These may lead to unqualified retreaded tires.

1, carcass problem

The carcass has more than five wounds, wounds larger than 5CM, bead damage, cord and meridian damage, and cannot be refurbished. Generally, the operator can judge whether a tire can be refurbished by tapping and listening. Tire inflation detector and EDM detector can also be selected to detect the carcass.

2, the repair process is not fine

The repair process mainly includes external repair, internal repair, glue brushing and glue pouring. For external repair, use a wire wheel or a bowl-shaped metal grinding head to polish the worn parts, so as not to damage the buffer layer or belt layer as much as possible. When grinding, it is polished along the cord direction, and at the same time, a groove with a width of 20mm is polished on the shoulder to increase the bonding area between the tread and the carcass. The quality standard after small grinding is that all parts of the tire should be filed flat, the grinding lines should be uniform, and the thread end should not exceed 65438. For internal repair, patches should be provided for reinforcement according to the size of the through hole and the number of cord layers damaged by the through hole. According to the size of the patch, a wire wheel should be used for grinding. The thick oil skin adhesive can be kept, but the new rasping surface must be polished. The actual grinding size is more than each side of the patch 10mm. When the patch is matched, the center position of the patch must be aligned with the center position of the through hole or the through hole, and cannot be offset. After matching the patch, the model number of the patch should be marked next to it.

3. Poor quality of raw materials

The quality of tread rubber directly affects the mileage of tires. The function of the intermediate cushion rubber is to pull the tread towards the carcass without separation. Degumming is often related to the buffer glue in the middle. Friends who buy flat tires can think for themselves. Spend 800 yuan to buy a 1200R-20 tire and run 50,000 kilometers. The same type of tire 1000 yuan can run more than 80 thousand kilometers. Is it profitable to spend more than 200 yuan on tires and drive more than 30 thousand kilometers? If you want to buy cheap tires, manufacturers have to use cheap materials.

4. The curing temperature and pressure are unstable

Many tire turners may not know this problem, because the equipment manufacturers who supply them may not know the principle of this.

Vulcanization is a chemical reaction, the temperature is 1 15 degrees Celsius, and the error is 1 degrees Celsius. The inner tube pressure is 8kg, the envelope pressure is 4kg, and the vulcanizing tank pressure is 6kg, with an error of 0. 1-0.5kg ... When the middle gasket reaches the specified temperature and pressure, the vulcanization reaction will occur, and the air in the middle gasket can be effectively exhausted by using the pressure difference. On the other hand, if the temperature and pressure can't be reached or exceeded, the accurate chemical reaction can't be carried out, and there is air in the tire, so the bulging phenomenon will occur.