Current situation and analysis of plastic packagin

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Current situation and analysis of plastic packaging materials in China (III)

2. PVDC coextrusion shrink film (bag) has made progress in chilled meat packaging

in recent years, with the rapid development of China's economy and the acceleration of internationalization, China's meat consumption structure has also changed significantly, and raw meat shows a development trend from hot fresh meat to frozen meat, and then from frozen meat to chilled meat

although the cold chain in China has tended to be perfect and standardized, chilled meat can not completely inhibit the growth and reproduction of some psychrophilic microorganisms in the range of 0 ℃ ~ 4 ℃ used for cold storage. Therefore, the shelf life of chilled meat is short, and the surface browning and juice loss are serious. The storage period is generally 3-7 days, which cannot fully meet the needs of market circulation

how to prolong the fresh-keeping period of chilled meat is the key to the development of chilled meat. The new packaging technology is also crucial to prolong the fresh-keeping effect of chilled meat. According to authoritative information, the variety and quality of meat products in China are far behind the world's advanced level, mainly due to the lagging development of meat packaging technology. Choosing appropriate packaging materials and packaging technology can play a very significant role in extending the fresh-keeping period of chilled meat and ensuring the hygiene and quality of meat

a, modified atmosphere packaging technology

also known as gas replacement packaging, through the use of appropriate gas composition to replace the gas environment in the packaging, so as to change the atmosphere in the packaging, so as to inhibit the growth and reproduction of microorganisms and extend the fresh-keeping period of packaging. Multi layer coextrusion high barrier film used in modified atmosphere packaging technology is mainly made by tape casting and film blowing, which does not have shrinkage, and the thickness is generally 90 μ m~150 μ m. With high transparency and puncture resistance, it can inhibit microbial reproduction by changing the gas environment inside the package

b, vacuum packaging technology

through the form of vacuum pumping, make the packaging close to the meat, inhibit the seepage of water in the meat, block oxygen, inhibit bacterial reproduction, and improve the safety of the meat. Vacuum body fitted packaging and heat shrinkable packaging are widely used in the packaging of segmented meat. Vacuum shrinkable packaging is mainly made of multi-layer coextrusion double bubble blowing film. PVDC is used as barrier layer. After coextrusion with other special materials by double bubble method and off-line treatment, the product shrinkage is about 35% - 45%. Using the heat shrinkability of the shrink film to make it close to the surface of meat products, it can prevent moisture seepage, and the thickness is generally 50 μ m~90 μ m。 PVDC coextrusion films with these structures have been researched and developed since the 1990s. In 2005, they finally developed coextrusion shrink film bags for cooling meat in Qinhuangdao jiaruite plastic technology company and Hebei Xingtai Jinguang company, and will go to the market

by using PVDC as the intermediate layer and co extruding film to package the chilled meat, the fresh-keeping period of the meat can be prolonged. It expands the sales field of meat processing enterprises and can cover long-distance markets at home and abroad. For export-oriented enterprises, it greatly improves the storage period of meat products in long-distance transportation and ensures the quality of meat products. Some domestic raw meat export-oriented enterprises and packaging production enterprises, keen to capture this information, have begun to use and produce this new high barrier packaging material. Such as grassland Xingfa, Changchun Haoyue, Baoquanling, Hua'an cattle industry, etc. Luohe Shuanghui, Zhengzhou Baolan Packaging Technology Co., Ltd. and other enterprises committed to the development and research of new packaging products in China are stepping up the development of this packaging material

3. The application market of multi-layer coextrusion winding film has initially taken shape.

stretch winding packaging was first adopted by European and American developed countries in the 1970s as a packaging technology, which developed from shrink packaging. China began to develop stretch winding from the late 1980s to the end of 2013 (hereinafter referred to as winding film) In the early 1990s, with the rapid economic development, winding film was popularized and applied, and the demand grew rapidly. In 2005, there were more than 100 manufacturers, with a production capacity of about 180000 tons and an output of 130000 tons. There were only more than 10 large-scale production lines, and the rest were small-scale production lines. With the continuous growth of China's packaging industry and foreign trade exports, the development of agricultural products and livestock forage preservation, as well as the popularity of the use of wrapping film in families and supermarkets, the demand for wrapping film will be increasing in the future

new progress has been made in the technological progress of degradable plastic packaging materials

over the past year, plastic packaging has made new progress on the road of green packaging. The development of polylactic acid and polyvinyl alcohol water-soluble films is accelerating, and new fully biodegradable polyvinyl alcohol films and fully degradable polyethylene starch alloys have been put on the market, as well as breakthroughs in the identification and blending modification technology of waste plastics. For example:

A. Guangdong Zhaoqing Huafang degradable plastic company has successfully developed fully biodegradable plastic particles, and this raw material has been made into fully biodegradable plastic. 4. Technical indicators: material film, the company's fully biodegradable plastic is different from degradable plastic with a degradation rate of only 10% - 30%, and it is not a masterbatch, but can set the degradation time, 100% degradation, and the main raw material used is starch, accounting for 60% Polyvinyl alcohol accounts for 20% and glycerol composite additives account for 20%. Its main technical indicators are that the biodegradation rate in 28 days is ≥ 66.6% (international standard is ≥ 15). The longitudinal and transverse strength of the film is> 300mpa, and the elongation at break is ≥ 600. The residual amount of PE film per mu is between 16 and 28 kg%, twice that of Italian mater Bi company. The production cost of granular material is lower than that of polyethylene, and it has better market competitiveness

B. Beijing Fengyang plasticizing Engineering Technology Co., Ltd. successfully developed a fully degradable starch polyvinyl alcohol alloy. According to the characteristics of polyvinyl alcohol, the melting softening point (230 ℃) is very close to its decomposition temperature (240 ℃), which is difficult to process. By adding modifiers, the plasticizing temperature of PVA is reduced, and the aggregate structure of PVA is changed. PVA is first plasticized in plasticizer solution to improve its thermal stability, Then it was blended with starch, and then melt mixing under high shear force was carried out by twin-screw and two-stage exhaust extruder with large aspect ratio (52:1), which made a breakthrough in technology and technology, and made a completely degraded film

C. Harbin Xinda high tech company has made a breakthrough in the identification and blending improvement technology of waste plastic bottles. The company uses far infrared spectroscopy (NIP) to identify discarded plastic bottles. This technology is fast and reliable, and can work normally even when the bottles are dirty. The established identification and sorting system is suitable for sorting transparent or slightly colored plastic bottles. The company has also successfully researched several polymer compatibilizers. This compatibilizer has no chemical reaction in the blending process of different kinds of plastics, and only depends on its own affinity and adhesion to the two blended polymers to make the two polymers with poor compatibility compatible, and finally become a polymer blend with good interface effect

information source: Modern Packaging

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