The 20th century is the historical period in which human progress and social development have been the fastest. In this short 100 years, scientists invented automobiles (industrialization), aircraft, tanks, satellites, computers, stainless steel, movies, faxes, air conditioners, optical fibers, color photos, electrocardiograms, microwave ovens, refrigerators, and insecticides. Agents, etc., have greatly improved people's lives, work, and residence. In the 20th century, it was the Green Revolution that had the greatest impact, the longest duration, and the largest number of participants. From the green industry to green agriculture, from green rivers to green deserts, from green environment to green cities, from green food to green housing, all of the “life support systems†on which human beings rely are reflected in the green revolution.
In the past 100 years, the world packaging industry has made great progress, great developments and many inventions. In reviewing the history of packaging for hundreds of years, we selected ten major packaging inventions or major packaging application technologies for evaluation based on the technical difficulty of the “packagingâ€, the breadth of applications, the scientific rationality, and the bright prospects. It aims to promote the development of packaging in the 21st century.
1. Cellophane
Invented Celluloid (Cellulose Film) in 1908, was the earliest and most brilliant packaging invention in the 20th century. Created a precedent for modern transparent flexible packaging.
In the spring of that year, the Swiss chemist Jacques Brandenbergev obtained the cellulose film for the first time when he used wood pulp as a spray test. Because of his "transparency" (Phane French), he named it " Transparent cellulose "Cellophane, Chinese transliteration as "celluloid."
In 1991, Brandenburg designed a machine for the trial production of celluloids, but the production was small. In 1924, Cellophane transferred technology to the world's largest DuPont (Du Pont) Buffalo plant. Since then, Cellophane officially entered the stage as a packaging material.
In 1926, Shinko Corporation in Tokyo, Japan, also started production of Cellophane. In 1930, Avisco Corporation in the United States, and many companies successively put into production. Celluloid is made from natural cellulose and has more than 100 varieties. Today, all manufacturers produce Cellophane films in different sizes, from inner packaging to outer packaging, from liner boxes to special bags. A single celluloid (PT) performs well but has poor moisture resistance. After coating a nitrocellulose membrane, it is a soft, moisture-proof, vapor-impermeable packaging film that is widely used because of its low cost. In the case of high-grade oxygen-barrier packaging, polyvinylidene chloride (PVDC)-coated cellophane (KPT) is excellent in oil resistance, airtightness, and moisture impermeability, the coating is thin, and the heat sealability is good. .
In 1963, in order to meet the needs of US supermarkets for multi-bone chicken and meat packaging, the United States developed a polyethylene coated cello packaging material. Since the price is lower than that of PVDC coating type, its application is very prosperous. When Celluloid entered the market, the price was high, and it was only used for luxury packaging. Between 1924 and 1939, the price dropped by 21 times (0.4 US dollars per pound) and the application was greatly expanded. At the end of the 1990s, the quality and cheap "Cellophane" will surely be rejuvenated in the tide of green packaging.
2. Polypropylene (PP)
Invented by Italy's Nata in 1954, Polypropylene, a biaxially oriented polypropylene (BOPP) film developed in the 1960s, became the main force for packaging, and was widely hailed as a “Packaging Queen†abroad.
In 1957, the Monte-Ericsson Company of Italy used the Zigler-Natta method to produce PP. In 1958, polypropylene extrusion film was first produced. In 1962, biaxially oriented polypropylene film began industrial production. B) OPP was rapidly developed as a new type of transparent flexible packaging material. By the end of this century, there were more than 150 companies in the world and more than 300 production lines. The annual output was close to 20 million tons; China's annual demand was close to 500,000 tons.
Polypropylene is non-toxic and odorless, has good moisture resistance and high mechanical strength. It is widely used in food, candy, cigarettes, tea, juice, milk, textiles, cosmetics and other packaging fields. BOPP is a more popular packaging than cellophane (such as PVC) due to its rich raw materials, excellent performance and versatility. Its simple manufacturing process and reasonable price make BOPP a more universal packaging than BOPET and BOPA, especially in compounding. Packaging, pearl packaging, food candy packaging plays an important role.
Polypropylene is the fastest growing and most widely used variety, but it also has its shortcomings. At present, new properties are being imparted through physical and chemical methods such as copolymerization, grafting, cross-linking, and blending (ABC technology). It is not only an excellent packaging material but also a high-quality engineering plastic.
ABC technology is the key technology for modern modification, namely alloy, blend and composite technologies. The first composite films were PE/PP/PE coextruded films developed by Kordite Company in the United States in 1963. They were first used for the packaging of bread and other foods. At that time, the three layers each had a thickness of 10 μm, 25 μm, and a peaceful co-existence of 0 μm. With various types of composite films, it has evolved in the direction of high-quality, diversified, and asymmetric composites.
In addition, in order to expand the use of polypropylene, foreign countries are developing high-strength, high-rigidity high-crystallinity polypropylene (HCPP), which has obvious seven advantages, has the ability to compete with other plastics.
3, Irradiated Packaging (Irradiated Packaging)
In 1896, the French physicist Antoine Henri Becquerel discovered radioactivity. In 1898, Mdane Curie discovered the radioactive elements of Radon and Radium, and in 1900 the French physicist Paul Villard. Γ-rays were found. Shortly afterwards, there have been applied subjects such as radiation and radiation techniques.
The use of γ-rays to irradiate packaged foods began in the 1970s and was originally used for packaged and fresh-keeping packaging of meat products, which was based on scientific theory and practice. The obvious advantages of radiation packaging at the time are: 1 to extend the shelf life of foods; 2 to use new packaging (if polymer) and to directly irradiate packaging products; 3 to maintain product characteristics; 4 to have no chemical residues (such as preservatives); 5 Reduce product losses; 6 Automation of packaging production process; 7 Save energy resources, protect the environment, the best green technology; 8 Good technical and economic indicators. According to the data from the International Atomic Energy Conference, the food storage energy-storage freezing method is 90 kW/h·ton, the pasteurization temperature is 230 kW/h·ton, and the heat sterilization is 300-700 kW/h·ton. The selective sterilization was 0.76 kW/h·ton, and the irradiation was completely sterilized to 6.3 kW/h·ton. Therefore, even in accordance with the requirements of the green environmental protection standard ISO 140000, it is an authentic green packaging process.
For example, a beef and pork packaged with a polymer material (radiator) can be stored for 2 months in a 3-50° d environment with a dose of 0.6 Mard of gamma rays; selective sterilization with heat treatment combined with irradiation can make The shelf life of the product at 5-20°d is extended to 5 months.
Milk is the best food given to us by nature, but it is difficult to keep fresh: Heat treatment (pasteurization, boiling) will cause some physical or chemical changes in milk, and the effect of treatment with electric field, ultraviolet light or chemical reagents Poor. Treatment with ionizing radiation (irradiation dose of 0.3 to 0.4 Mard) can sterilize the milk.
In the 1990s, the scope of radiation packaging products has also been greatly expanded, such as vegetables, dried fruits, convenience fabrics, cooked meat products, health drinks, Chinese and Western medicines, cosmetics, hygiene products, native products, food products, fresh fruits and vegetables, etc. The radiation source is gamma rays, x-rays, high-energy electron beams, etc. The radiation dose is strictly controlled within a safe range, leaving no radioactive material behind.
Due to the negative effect of the first atomic bomb in Hiroshima, radiation products have been in a state of “grabbing, covering, and concealing†for more than 30 years. In accordance with international regulations, China also formulated the “Irradiated Food Management Regulations†in China two years ago. Starting from June 1, 1998, all irradiated foods (including imports) sold on the Chinese market should be posted on the external packaging. There is an "IRRADIATED FOOD" green round logo pattern.
Irradiation can also be used for grafting, cross-linking modification of polymer materials, and also for disposal and regeneration of waste packaging materials.
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. (To be continued)
Excerpt from "Packaging the World" magazine 1999NO5 (Wen / Han Xiaofang Wang)
In the past 100 years, the world packaging industry has made great progress, great developments and many inventions. In reviewing the history of packaging for hundreds of years, we selected ten major packaging inventions or major packaging application technologies for evaluation based on the technical difficulty of the “packagingâ€, the breadth of applications, the scientific rationality, and the bright prospects. It aims to promote the development of packaging in the 21st century.
1. Cellophane
Invented Celluloid (Cellulose Film) in 1908, was the earliest and most brilliant packaging invention in the 20th century. Created a precedent for modern transparent flexible packaging.
In the spring of that year, the Swiss chemist Jacques Brandenbergev obtained the cellulose film for the first time when he used wood pulp as a spray test. Because of his "transparency" (Phane French), he named it " Transparent cellulose "Cellophane, Chinese transliteration as "celluloid."
In 1991, Brandenburg designed a machine for the trial production of celluloids, but the production was small. In 1924, Cellophane transferred technology to the world's largest DuPont (Du Pont) Buffalo plant. Since then, Cellophane officially entered the stage as a packaging material.
In 1926, Shinko Corporation in Tokyo, Japan, also started production of Cellophane. In 1930, Avisco Corporation in the United States, and many companies successively put into production. Celluloid is made from natural cellulose and has more than 100 varieties. Today, all manufacturers produce Cellophane films in different sizes, from inner packaging to outer packaging, from liner boxes to special bags. A single celluloid (PT) performs well but has poor moisture resistance. After coating a nitrocellulose membrane, it is a soft, moisture-proof, vapor-impermeable packaging film that is widely used because of its low cost. In the case of high-grade oxygen-barrier packaging, polyvinylidene chloride (PVDC)-coated cellophane (KPT) is excellent in oil resistance, airtightness, and moisture impermeability, the coating is thin, and the heat sealability is good. .
In 1963, in order to meet the needs of US supermarkets for multi-bone chicken and meat packaging, the United States developed a polyethylene coated cello packaging material. Since the price is lower than that of PVDC coating type, its application is very prosperous. When Celluloid entered the market, the price was high, and it was only used for luxury packaging. Between 1924 and 1939, the price dropped by 21 times (0.4 US dollars per pound) and the application was greatly expanded. At the end of the 1990s, the quality and cheap "Cellophane" will surely be rejuvenated in the tide of green packaging.
2. Polypropylene (PP)
Invented by Italy's Nata in 1954, Polypropylene, a biaxially oriented polypropylene (BOPP) film developed in the 1960s, became the main force for packaging, and was widely hailed as a “Packaging Queen†abroad.
In 1957, the Monte-Ericsson Company of Italy used the Zigler-Natta method to produce PP. In 1958, polypropylene extrusion film was first produced. In 1962, biaxially oriented polypropylene film began industrial production. B) OPP was rapidly developed as a new type of transparent flexible packaging material. By the end of this century, there were more than 150 companies in the world and more than 300 production lines. The annual output was close to 20 million tons; China's annual demand was close to 500,000 tons.
Polypropylene is non-toxic and odorless, has good moisture resistance and high mechanical strength. It is widely used in food, candy, cigarettes, tea, juice, milk, textiles, cosmetics and other packaging fields. BOPP is a more popular packaging than cellophane (such as PVC) due to its rich raw materials, excellent performance and versatility. Its simple manufacturing process and reasonable price make BOPP a more universal packaging than BOPET and BOPA, especially in compounding. Packaging, pearl packaging, food candy packaging plays an important role.
Polypropylene is the fastest growing and most widely used variety, but it also has its shortcomings. At present, new properties are being imparted through physical and chemical methods such as copolymerization, grafting, cross-linking, and blending (ABC technology). It is not only an excellent packaging material but also a high-quality engineering plastic.
ABC technology is the key technology for modern modification, namely alloy, blend and composite technologies. The first composite films were PE/PP/PE coextruded films developed by Kordite Company in the United States in 1963. They were first used for the packaging of bread and other foods. At that time, the three layers each had a thickness of 10 μm, 25 μm, and a peaceful co-existence of 0 μm. With various types of composite films, it has evolved in the direction of high-quality, diversified, and asymmetric composites.
In addition, in order to expand the use of polypropylene, foreign countries are developing high-strength, high-rigidity high-crystallinity polypropylene (HCPP), which has obvious seven advantages, has the ability to compete with other plastics.
3, Irradiated Packaging (Irradiated Packaging)
In 1896, the French physicist Antoine Henri Becquerel discovered radioactivity. In 1898, Mdane Curie discovered the radioactive elements of Radon and Radium, and in 1900 the French physicist Paul Villard. Γ-rays were found. Shortly afterwards, there have been applied subjects such as radiation and radiation techniques.
The use of γ-rays to irradiate packaged foods began in the 1970s and was originally used for packaged and fresh-keeping packaging of meat products, which was based on scientific theory and practice. The obvious advantages of radiation packaging at the time are: 1 to extend the shelf life of foods; 2 to use new packaging (if polymer) and to directly irradiate packaging products; 3 to maintain product characteristics; 4 to have no chemical residues (such as preservatives); 5 Reduce product losses; 6 Automation of packaging production process; 7 Save energy resources, protect the environment, the best green technology; 8 Good technical and economic indicators. According to the data from the International Atomic Energy Conference, the food storage energy-storage freezing method is 90 kW/h·ton, the pasteurization temperature is 230 kW/h·ton, and the heat sterilization is 300-700 kW/h·ton. The selective sterilization was 0.76 kW/h·ton, and the irradiation was completely sterilized to 6.3 kW/h·ton. Therefore, even in accordance with the requirements of the green environmental protection standard ISO 140000, it is an authentic green packaging process.
For example, a beef and pork packaged with a polymer material (radiator) can be stored for 2 months in a 3-50° d environment with a dose of 0.6 Mard of gamma rays; selective sterilization with heat treatment combined with irradiation can make The shelf life of the product at 5-20°d is extended to 5 months.
Milk is the best food given to us by nature, but it is difficult to keep fresh: Heat treatment (pasteurization, boiling) will cause some physical or chemical changes in milk, and the effect of treatment with electric field, ultraviolet light or chemical reagents Poor. Treatment with ionizing radiation (irradiation dose of 0.3 to 0.4 Mard) can sterilize the milk.
In the 1990s, the scope of radiation packaging products has also been greatly expanded, such as vegetables, dried fruits, convenience fabrics, cooked meat products, health drinks, Chinese and Western medicines, cosmetics, hygiene products, native products, food products, fresh fruits and vegetables, etc. The radiation source is gamma rays, x-rays, high-energy electron beams, etc. The radiation dose is strictly controlled within a safe range, leaving no radioactive material behind.
Due to the negative effect of the first atomic bomb in Hiroshima, radiation products have been in a state of “grabbing, covering, and concealing†for more than 30 years. In accordance with international regulations, China also formulated the “Irradiated Food Management Regulations†in China two years ago. Starting from June 1, 1998, all irradiated foods (including imports) sold on the Chinese market should be posted on the external packaging. There is an "IRRADIATED FOOD" green round logo pattern.
Irradiation can also be used for grafting, cross-linking modification of polymer materials, and also for disposal and regeneration of waste packaging materials.
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. (To be continued)
Excerpt from "Packaging the World" magazine 1999NO5 (Wen / Han Xiaofang Wang)
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