Overview of BOPP film development at home and abro

2022-08-11
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Overview of BOPP film development at home and abroad (I)

Abstract: since the industrialization of BOPP film in 1962, there are currently more than 200 production enterprises and nearly 500 production lines in the world. In 2003, the world's demand for biaxially oriented polypropylene (BOPP) film has reached 4.3 million tons, and it is predicted that the global annual demand for BOPP film will reach 6 million tons by 2010. This paper briefly describes the development history, main characteristics, classification and application of BOPP film at home and abroad, the current production technology and future development direction, as well as the new trends of BOPP film raw materials, production equipment and market

introduction

biaxially oriented polypropylene film (BOPP) has the advantages of light weight, non-toxic, odorless, moisture-proof, high mechanical strength, good dimensional stability, good printing performance, good transparency and so on. It is widely used in the packaging of food, candy, cigarettes, tea, fruit juice, milk, textiles and so on, and is known as the "Queen of packaging". BOPP film has become a more popular packaging material than paper and polyvinyl chloride (PVC) due to its wide application, low pollution and protection of forest natural resources; The simple and reliable manufacturing process and reasonable price make it a more commonly used packaging material than BOPET film and BOPA film

1. The development history of BOPP film at home and abroad

bopp film production technology was first created by Italian Montecarlo company in 1958. In 1962, it realized industrialization and monopolized production in Europe, America and Japan. Since then, BOPP film has developed rapidly. At present, there are more than 200 production enterprises and nearly 500 production lines in the world, such as electric pull general testing links such as load, displacement, deformation, etc

since the early 1960s, Beijing Research Institute of chemical industry (later moved to xianchenguang Research Institute of chemical industry), Beijing Research Institute of electrical appliances (now Guilin Research Institute of electrical appliances) and Shenyang Research Institute of chemical industry (later moved to xianchenguang No. 3 plant) have explored their own design and trial production of two-way stretching processes and equipment, and have successively built and put into operation some small-scale and simple equipment production lines, At that time, BOPET and BOPP films were mainly used to produce electrical insulation and dielectric, and BOPP films were officially produced in 1975. In order to meet the extensive needs of more industries, China has introduced some or a full set of large-scale and highly automated production lines from developed countries in Europe, Japan and the United States since 1980. By 1985, there were only four low-speed import packaging film production lines of 3000-6000 tons in Foshan, Guangzhou, Beijing and Yanshan, with an annual production capacity of only 18000 tons; From 1988 to 1989, it entered the "growth period". By 1990, the country had developed 17 BOPP plants and 21 low-speed production lines, with an annual production capacity of 80000 tons, an increase of 4.4 times in five years; From 1997 to 1998, China's BOPP entered the second peak period of capacity expansion. At the same time, the technological innovation of BOPP made breakthrough progress, and the annual output of 15000 tons of high-speed lines was widely used. By 1998, there were 43 BOPP plants and 60 production lines in the country (of which 15 were from 10000 to 15000 tons of high-speed lines). The annual output capacity exceeded 400000 tons, with a five fold increase in eight years, making it one of the "bright spots" industries of China's economic growth. Attracted by the "market and benefits" and the scientific and technological advantages of wide and high-speed production lines, China's BOPP entered the third peak of capacity expansion from 2002 to 2003. According to the survey and Statistics: it has a soft touch similar to Cr, SBR or PU foamed materials. By the end of 2002, there were 56 BOPP manufacturers and 92 production lines in the country (including 25 high-speed and wide-width production lines of 15000 ~ 25000 tons), with an annual production capacity of about 960000 tons (including 580000 tons of high-speed lines, accounting for 60%). By the end of 2003, China had 82 BOPP film manufacturers, 123 production lines and a production capacity of about 1.4 million tons. Since then, China has become a major producer of BOPP in the world, and new changes have taken place in the relationship between supply and demand in China and even Asia

it is particularly worth mentioning that Shantou Far East equipment company manufactured a complete set of BOPP film production line equipment close to international similar products in December 2002, and the trial machine was successful. The production line is a three-layer coextrusion production line, with a width of 4.2 meters and a maximum mechanical speed of 180m/min

2 current situation of BOPP membrane

2 BOPP film production method

biaxial stretching is a technology developed for subsequent orientation or synchronous orientation of thermoplastic materials. At present, the production of BOPP film mainly includes tube film method and flat film method

biaxial stretching mode: (1) tube membrane method; (2) Flat film method can be divided into successive biaxial stretching and synchronous biaxial stretching

tubular membrane method has the advantages of simple equipment, small investment, less land occupation and quick effect. However, due to its low output, large thickness tolerance and large thermal shrinkage, it has not developed much recently. The products made by synchronous biaxial stretching in the flat film method have the advantages of isotropy, but they have not been developed due to complex equipment, difficult manufacturing and high cost. Step by step biaxial stretching is the method adopted by most production enterprises at present. Although the products produced differ longitudinally and horizontally in tensile strength, elongation at break, thermal shrinkage and other properties, it has little impact on product quality, but it has the advantages of large output, fast speed, wide range, stable product quality and so on. The process flow is as follows:

raw material preparation → melting → plasticizing extrusion → filtration → longitudinal stretching → transverse stretching → corona treatment → winding → aging treatment → slitting → finished products

a thickness of 10 can be obtained by gradual biaxial stretching μ m~60 μ M of finished film, which can be used as single-layer or laminated packaging materials. By changing the equipment and operating conditions, the thickness of the bottom film used as the capacitor can also be produced to be 2 μ M film or used for inkjet printing, shopping bag bottom film, etc., with a thickness of 170 μ M synthetic paper

2. 2 BOPP film performance, category and use

BOPP film has the advantages of high transparency, good gloss, good barrier, high impact strength, low temperature resistance and so on. Its disadvantage is that it is easy to shrink the film during heat sealing (except that the heat shrinkable smoke film uses its heat shrinkable performance). Its comprehensive performance is better than moisture-proof cellophane, polyethylene (PE) film and PET film. BOPP film also has excellent printing effect. The representative physical property data is: turbidity 1.5%; Gloss 85%; Tensile strength (longitudinal/cannot be damaged by hammering) 120/200mpa; Elongation at break (longitudinal/transverse) 180%/65%; The elastic modulus is 1700 ~ 2500mpa; The embrittlement temperature is -50 ℃

BOPP film can be compounded with other materials with special properties to further improve or improve performance. Commonly used materials include PE film, salivary polypropylene (CPP) film, polyvinylidene chloride (PVDC), aluminum film, etc

bopp film has the lowest price and the largest dosage in biaxial tensile film, which is very competitive. According to the purpose, it can be divided into:

ordinary film: it is generally used in printing, compounding, coating (adhesive tape, PVDC coating, etc.)

heat sealing film: cigarette packaging, ordinary packaging and pearlescent film packaging (mainly used for frozen food and candy packaging)

metallized film: suitable for vacuum aluminum plating

capacitor film: used to make capacitors and metal film capacitors

special film: such as for shopping bags, mail bags, inkjet printing, as well as label film, pull film, etc

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