China’s LLDPE Self-sufficiency to Improve

By Gao Liping, China National Chemical Information Center

Linear low-density polyethylene (LLDPE) is a substantially linear polymer like high-density polyethylene (HDPE), with a significant number of short branches. It is commonly made by copolymerization of ethylene with higher alpha-olefins such as butene, hexene, or octene. LLDPE differs structurally from the conventional low-density polyethylene (LDPE) because of its absence of long chain branching. LLDPE has higher tensile strength and higher resistance to impacts and punctures than does LDPE. It is very flexible and stretchy. It can be used to make thinner films with better resistance to environmental stress cracking. It also has good resistance to chemicals and useful electrical properties. However, it is not as easy to process as LDPE, has lower gloss, and a narrower temperature range for heat sealing.

Global capacity increases gradually

In recent years, with the fast increase of demand for polymer films and injection-molded products, the output of LLDPE increased rapidly, making LLDPE the second most common variety of polyethylene after HDPE. LLDPE has penetrated almost all traditional markets for polyethylene, including thin films, injection-molded products, pipes and tubes, cables and wires, etc.
In 2013, the global capacity for LLDPE was over 30 million t/a, and the output was over 20 million tons. The United States has the largest LLDPE production capacity, followed by China and Saudi Arabia. Major producers include Dow, ExxonMobil, SABIC, Sinopec, Borealis, PetroChina, Nova Chemicals, etc. During the next five years, with producers in Asia, North America, the Middle East, and Central and Eastern Europe continuing to expand capacity, the global capacity for LLDPE will increase steadily, and as LLDPE will continue to replace LDPE worldwide, consumption is also expected to increase steadily.
The global LLDPE consumption in 2013 was 25.8 million tons, up 4.8% year-on-year. The consumption structure was as follows: thin film products (including plastic wraps and agriculture films) accounted for 70%; injection-molded products, about 8%; rotational molding products, cables and wires, pipes, about 20%.

Domestic capacity expands dramatically

China began to build LLDPE production units in the late 1980s. Starting in the present century, Sinopec (including Zhongyuan, Guangzhou, Qilu and Maoming branches) and PetroChina (including Jilin and Dushanzi branches) began to expand their LLDPE capacities. Sinopec Yangzi Company, Shanghai SECCO Petrochemical Co., Ltd. and PetroChina Lanzhou Company each constructed a new LLDPE unit with a capacity of 200 – 300 kt/a, significantly promoting China’s LLDPE production.
After the rapid expansion from 2009 to 2013, China’s capacity for LLDPE reached 6.557 million t/a in 2013. See Table 1 for detail. The output in 2013 was 4.177 million tons, up 7.3% year-on-year. As some LLDPE units that use a gas phase process can be switched over to producing HDPE, the overall operating rate for LLDPE was relatively low.
LLDPE copolymerized by using ethylene and butene-1 is the most common variety. However, varieties using hexane-1 or octene-1 as the comonomer perform better. As there is still no large-scale production unit for hexane-1 or octene-1 in China and their import prices are high, LLDPE resin produced in China mainly incorporates butene-1 as the comonomer. A small amount of LLDPE with hexane-1 as the comonomer is produced in China, mainly used to make stretch wrap films. There is no production of LLDPE with octene-1 as the comonomer in China.  

Table 1   Major LLDPE producers in China, 2013 (kt/a)


Company?    ??Capacity??    ??Remarks
Sinopec    3 260?????    12 units (including JVs)
PetroChina??????    2 492?????    11 units
Shenghua Baotou Coal Chemical Company????    ?300?????    1 unit
Panjin Ethylene Co., Ltd.?    ?145?????    1 unit
CNOOC    ?260?????    1 unit
ChemChina    ?100?????    1 unit
Total    6 557    



In the future, low cost natural gas-based polyethylene products from the Middle East and shale gas-based polyethylene from the United States will pour into China, with significant impact on Chinese polyethylene producers using petroleum as raw material. Moreover, with coal-to-olefins technology maturing and its production scale expanding in China, enterprises in the traditional petroleum-ethylene-polyethylene industrial chain will face more pressure. The consumers of high-end polyolefin products heavily rely on imports, mainly from Europe, Japan, South Korea and the United States. Therefore, in order to improve profitability, enterprises are suggested to develop high-end specialty varieties of LLDPE.
Sinopec and PetroChina are the two largest LLDPE producers in China. In 2013, Sinopec’s capacity for LLDPE was 3.26 million t/a, accounting for 49.7% of the domestic total; that of PetroChina was 2.492 million t/a, accounting for 38.0% of the domestic total.
Due to the relatively large supply gap of polyethylene in China, most ethylene projects constructed in recent years are equipped with downstream production lines to produce HDPE and LLDPE. Currently, there are 19 LLDPE units either under construction or in preparation in China, of which 8 projects are exclusively for LLDPE production and 11 projects can also produce HDPE. It is noteworthy that most of these new projects are coal-to-chemical projects. Therefore, China’s LLDPE industry is trending toward diversified raw materials. Figure 1 shows the production of LLDPE in China from 2002 to 2013 and a projection to 2018.
Polyethylene is one of the main bulk chemicals imported to China. Of all polyethylene varieties imported to China, the import volume of LLDPE ranks second only to that of HDPE. The import volume was far below 2 million tons before 2009, at which time it increased drastically to 2.201 million tons, up 49.1% year-on-year. In the following years, the number was between 2.3 and 2.5 million tons. It was 2.353 million tons in 2013, up 2.0% year-on-year. Figure 2 shows China’s foreign trade of LLDPE resin from 2002 to 2013 and a projection to 2018.

Domestic demand increases rapidly

From 2008 to 2013, the demand for LLDPE in China increased drastically with an average annual growth of 12.6%. In 2013, China implemented the “Green Hedge Action” to restrict the import of recycled plastics to China, significantly promoting the consumption of new LLDPE resin. However, the export of plastic products from China has been affected by slow recovery of the global economy. In 2013, the consumption of LLDPE in China was over 6 million tons, up at least 6% year-on-year.
In China, more than 80% of LLDPE is used for the production of thin films, and the balance is mainly used to produce injection-molded products, cable and wires, rotational molding products, etc.
Two major application fields of LLDPE thin films are packaging and agriculture. The consumption of LLDPE in making agricultural films has increased year by year. Compared with LDPE, LLDPE has better resistance to impacts, to penetration and to environmental stress cracking, so the mulching films made from LLDPE are 20%-25% thinner than those made from LDPE. Therefore, LLDPE is gradually replacing LDPE to produce mulching films. As greenhouse films used for vegetable farming, garden nurseries and livestock feeding require excellent properties of light transmission, weatherability and heat preservation, they are often made from HDPE blended with LDPE or LLDPE. To reduce costs, greenhouse film producers are making efforts to increase the proportion of LLDPE in blends.
In addition, the consumption of LLDPE in the production of stretch wrap films increased rapidly in recent years. Stretch wrap film is frequently used to unitize pallet loads but also may be used for bundling smaller items. It has advantages including high stretching-strength and elongation, transparency, dust protection and low cost.
Another large application of LLDPE is in making injection-molded products. Although the total consumption of injection-molded products in China is quite large, most of them are made from polypropylene (PP) or HDPE. LLDPE is often blended into PP or HDPE to improve product performance, and its consumption in this area has increased rapidly in recent years. LLDPE varieties made in China for injection molding include 7144, 7147, 8320, etc., and imported varieties include 204P, 2020, 7144, 7147, etc.
LLDPE can also be blended with other polymers to produce rotational molding products, covering layers, tubes and pipes, wires and cables, blow molding products and filaments. LLDPE is used to make rotational molding products such as large toys, garden furniture and components for waste handling systems. For tubes and pipes, LLDPE is used in hoses of vacuum cleaners as it has long bending fatigue life. It is also used to make protective sheaths for cables and wires. LLDPE alone can be used to produce small blow-molded products like drug bottles, beverage bottles, etc.   

Conclusion

From 2008 to 2013, with a batch of large-scale refineries and petrochemical-integrated factories starting operation, LLDPE capacity and output both increased fast, with respective average annual growth of 20% and 15%. However, a huge supply gap still remains in China. In the next few years, many coal-to-chemicals plants will be put into production, and the China’s LLDPE self-sufficiency will increase. Meanwhile, the consumption of LLDPE in China will be further promoted by the development of agricultural film production, the packaging industry and injection molding. In general, the supply gap will remain huge in the near future while self-sufficiency will increase gradually.