Top Ten Packaging Inventions of the 20th Century (2)

4, Polyester
The polyester (PET) resin that was invented in 1847, researched in 1922, and completed in 1941 is the longest and most widely used in the modern packaging industry, and has the largest number of family members (mostly polyesters) and the brightest packaging materials. Packaging materials and packaging products.
In 1847 the Swedish chemist Benzelius chemically synthesizes the first polyester (PET) resin but nobody cares. In 1922, DuPont chemists in the United States conducted polymer research with W. Carethers. Invented nylon in 1926, but did not complete the final study of PET. In 1941, the British chemists Whinfield and Dickson finally made poly(ethylene terephthalate) resins from the condensation of terephthalic acid and ethylene glycol on the basis of Carlos.
Thermoplastic polyester resins (broad refers to) are polymers composed of aromatic dicarboxylic acids and aliphatic aromatic diols. PET was the earliest discoverer, and due to its excellent performance, the host country's packaging film was rapidly developed. At that time, because of its poor moldability, PBT (polyethylene terephthalate) with excellent processability was widely used in the 1960s. At the same time, PEN with excellent overall performance has been used in certain applications, but it has been curbed because of its high price. Subsequently, PBN and PTT polyester resins were also introduced.
In 1987, PET resin began to realize commercial production and became one of the pillars of plastics. With the rapid development in the past two years, PET used the fastest, PET film took the second place, and PET fiber shrank. Recently, the development rate of PET in the world has slowed down and prices have dropped. The global PET demand growth rate will drop to about 4% after pre-launching in 2000.
In July 1995, Amoco Corporation of the United States first realized the commercial production of PEN raw material NDC (dimethyl naphthalene dicarboxylate), which led to a significant drop in PEN prices and became PET's strongest competitor. PEN resin is similar to PET in that it merely replaces the benzene ring of PET with a naphthalene ring, so all aspects must be better than PET. Especially in the heat resistance, chemical resistance, radiation resistance, gas barrier, UV resistance is also better than PET and so on. Due to its excellent performance, PEN can be used as a hot filling container, pressure vessel (beer bottle) and other chemical engineering fields in addition to PET packaging. It is the "star" and "new polyester" for the world.
In June 1997, the British Shell officially announced the listing of PTT (poly(trimethylene terephthalate)). Due to the development of a new process for the production of propylene glycol, the PTT price is comparable to that of PET, and the PTT also has the high performance of PET and the excellent molding processability of PBT, so it is widely used.
In addition, polyester resins include PBS (polybutylene succinate), PBSA (polybutylene adipate), and PES (ethylene poly (ethylene succinate) ester). Degradable plastics are new products for green packaging.

5. Metallocene Polymers
In 1951, Wilkinson developed a ferrocene C5H52Fe coordination compound that opened the way for the most widely used and most versatile new polymers in this century.
After the invention of ferrocene, many scientists engaged in research work in this area, and developed new complex compounds such as zirconocene, titanocene, and hafnocene.
In 1976, Kaminsky et al. synthesized polyethylene (mPE) using a zirconocene and methylaluminoxane (MAO) catalytic system. From then on, he began to investigate the new wave of metallocene catalysts and new metallocene polymer materials.
In 1991, based on the single active catalytic technology (SSC) successfully developed by Exxon in the 1980s, the company first successfully produced metallocene polyethylene (mPE) on 15,000 tons of high pressure equipment, and started metallocene plastics. The industrial production has opened up a new era of polyolefin production.
Compared with the traditional production technology (LDPE, HDPE, LLDPE), mPE has more advantages: its film strength is high, the vertical and horizontal uniformity, flexibility, puncture resistance, impact resistance are good, especially the heat sealing performance is good ( Low sealing temperature, wide heat-sealing temperature and short heat-sealing time, etc., good sealing performance, good barrier properties, most suitable for packaging materials, to be thinner, stronger, better and cheaper green The direction of development is expected to reach 12 million tons in 2005.
Metallocene polypropylene (mPP) was developed in the 1980s and began industrial production in the 1990s, which is one step higher than traditional PP production (ZN catalysis).
The development and production of mPP are mainly Fina Corporation, Hoechst Corporation, Exxon Corporation and Mitsui Corporation. In 1997, the first Tarpor company in Europe to produce mPP (jointly built by BASF and Hoechst) was put into production. In 1998, Japan's Hsu-Supplier's mPP went into production. Due to the excellent properties of mPP, such as transparency, gloss, flexibility, impact resistance and the like, it is mainly used in the packaging field.
In 1985, Japan Ishihara first developed polystyrene (mPS) using a titanium metallocene catalyst system (CpTiCl3/MAO). (Cp stands for Maukey).
In 1996, Japan's Idemitsu Chemical and Dow Chemical Company of the United States successively realized the industrial production of mPS. The processing of mPS can be used in injection molding, compression molding, extrusion molding and thermoforming processes. Its application areas mainly include packaging, films, injection molded parts and other thermoplastic engineering plastics.
The use of metallocene catalysts for the production of copolymers began in the 1990s. At present, there are mainly ethylene-styrene copolymers, propylene-ethylene-butylene terpolymers and so on. In particular, the c-high olefin-propylene copolymer (HAO-PP) developed by Exxon in recent years is particularly popular.
In 1999, the Dow Plastics Company of the United States will put into production the production line with an annual output of 32,000 tons, which will become the world's largest manufacturer of ethylene-styrene copolymers.

6.Anticorrosin Packaging Technology
In 1923, the British scientist UREvans first proposed the theory of atmospheric corrosion, and pioneered the era of modern anti-corrosion packaging technology.
Anti-corrosion packaging is the oldest traditional technology in human history. In order to survive, human beings learned how to use raw materials such as triads, earth tar, and gypsum for preservation packaging as early as 4500 years ago. In 1907 German archeologist Borchaldt discovered the world's oldest metal pipe. According to scientific methods, it was concluded that it was the product of mankind over 4,000 years ago, and some people thought it was a masterpiece of the extraterrestrial visitor.
In 1931, scientist Veron proposed the principle of critical humidity corrosion, which has become the theoretical basis of modern anti-corrosion packaging design. In 1939 Veron invented the artificial corrosion test method and proposed the phenomenon of water vapor condensation. In the Second World War, anticorrosive (erosion) research work was temporarily suspended. In 1963, American scientist MGFontana proposed corrosion engineering.
In 1928, the United States began a 20-year corrosion test study. In 1964, German scientist R. Meldau performed microscopic research using advanced equipment such as electron microscopes.
With the development of industry, corrosion losses have only increased. For this reason, the 1961 International Corruption Conference (ICMC) was held. In 1970, the International Organization for Standardization (ISO) set up a corrosion protection mechanism. In 1981, China began to participate in international conferences. In the same year, the Chinese Society of Antiseptic Packaging was established.
Corrosion is the enemy of the national economy. The developed countries such as the United States, Britain, the Soviet Union, France, Japan and Germany lose between 100 and 30 billion U.S. dollars each year, and China’s losses are about 36 billion U.S. dollars. According to reports, China's annual loss of steel caused by corrosion accounts for 10% of the annual output, reaching as much as 10 million tons. It is possible to build 30 Beijing-Guangzhou Railways. This shows the importance of anti-corrosion packaging.
Corrosion is ubiquitous. Chemicals, transportation, vehicles, ships, machinery and equipment, household appliances, and packaging industries all have the threat of corrosion. There are as many as 50 or 60 types of corrosion appearance, making it difficult to prevent them.
For packaging, anti-corrosion packaging has a double meaning: First, it must have anti-corrosion (erosion) protection function for packaging products; second, it must also carry out anti-corrosion packaging of packaging materials packaging containers (according to the definition of corrosion, the environmental damage of materials, such as Stress cracking, plastic aging, metal rust, stone weathering, etc. are all areas of corrosion). In particular, products exported through the ocean, such as optical, mechanical, electrical, high-grade, fine, sharp and other equipment, as well as chemical, food and other anti-corrosion packaging are more important.
Anti-corrosion packaging is a comprehensive protection technology, often using moisture-proof packaging, anti-mildew packaging, rust-proof packaging, gas phase packaging, nitrogen filling packaging, oxygen removal packaging, dry packaging, rust-proof grease, silicone and other technical methods. The quality of packaging often depends on the length of the storage period. Long-term storage (more than 10 years) of defense products is very strict. Anti-corrosion packaging is also used for the protection of unearthed cultural relics. For example, the “colored pottery bowl” that was unearthed more than 2000 years ago in the tombs of the First Emperor Qin Shihuang and the Han Jing Emperor’s Mausoleum was able to meet the people of the world. The significance is even greater.