Classification of flexible packaging
1. Classified by composite process
1) dry coating organic solvent adhesive composite soft bag;
2) wet coating inorganic binder composite soft bag;
3) extruded film laminate composite package;
4) Multi-layer co-extrusion (through two or more extrusion heads) composite soft pack;
5) hot melt coating composite soft bag;
6) solvent-free (ie solid binder) composite soft pack;
7) physical vapor deposition composite soft pack;
8) physical vapor deposition composite soft pack;
9) Mixed composite soft pack;
10) The above method combines a composite soft pack or the like.
2, according to composite material classification
1) paper and paper;
2) paper and metal foil;
3) paper and plastic film;
4) plastic film and plastic film;
5) plastic film and metal foil;
6) plastic film and metal film;
7) plastic film and substrate material;
8) plastic film and inorganic compound film;
9) plastic film and organic compound film;
10) amorphous plastic film and plastic film;
11) compounding the substrate with the nano-type ultrafine particles;
12) Special additives for substrate coating or impregnation
13) Multi-layer composite of composite materials.
3. Classification by composite form
1) large area (even) composite;
2) Partial compounding, such as compound strengthening or imparting certain functions only at the sealing portion or strengthening portion of the package;
3) Composite sheet or composite bag, which combines special functions in one place to play the overall function;
4) Gradient composite (or non-uniform composite), changing the concentration, composition or thickness of the additive material in the thickness direction (or length direction) of the composite film as needed;
5) Special compound, such as composite according to mesh pattern. Among them, the third, fourth and fifth are green technology.
4, according to the composite utility classification
1) Enhanced composite packaging;
2) High-impedance type composite packaging (gas barrier, water blocking, oil resistance);
3) Anti-corrosion type (anti-corrosion and anti-rust) composite packaging;
4) Anti-electromagnetic field (dry worry) composite packaging;
5) antistatic composite packaging;
6) Bio-composite packaging (fruit heat-promoting, fish keep-alive, insect-proof, mildew-proof);
7) Preservation composite packaging (for fruits and vegetables and meat products);
8) Composite packaging for cooking (such as cooking, microwave baking, etc.);
9) Intelligent composite packaging;
10) Ultra-micro-nano composite packaging.
Flexible packaging material and classification
1, LDPE, LLDPE resin and film
China's composite film started from the late 1970s. From the early to the mid-eighties, China began to introduce some extruders, blown film machines and printing machines to produce simple two-layer or book-layer composite materials. Such as extrusion composite BOPP / PE, paper / PE, pp / PE; dry composite BOPP / PE, PET / PE, BOPP / AL / PE, PET / AL / PE, etc., which LDPE resin and film, often A certain proportion of LLDPE is blended to enhance its strength and stiffness. Mainly used in the packaging of instant noodles, biscuits, mustard and other foods. Generally, coating grade LDPE resins are available; IC7A, L420, 19N430, 7500, etc.; blown film grade LDPE resins are: Q200, Q281, F210-6, 0274, etc.; LLDPE resins are: 218w, 218F, FD21H, and the like.
2, CPP film, CPE film
From the late 1980s to the early 1990s, with the introduction of a new generation of flexible packaging equipment and casting equipment, the scope of packaging contents was further expanded, and some puffed foods, cereals and other packaging bags required higher transparency, and boiled, high temperature. The sterilization products have successively asked the market, and the requirements for packaging materials have also increased accordingly. The inner layer materials mainly based on LDPE and LLDPE can no longer meet the requirements of the above products. The casting method produces a good heat sealability. Oil resistance, transparency, aroma retention, and special low-humidity heat-sealing and high-temperature cooking CPP are widely used in packaging. The aluminum-plated CPP developed on this basis is also rapidly and widely used due to its metallic luster, aesthetics, and barrier properties. And the CPE film produced by the casting method is further used because of its one-way tearability, low-temperature heat sealing, and good transparency.
3, MLLDPE resin
With the continuous development and changes in the packaging market, there are more and more special requirements for packaging. The DOW Chemical Company of the United States produced a metallocene polyethylene MLLDPE by metallocene catalyzed polymerization. Such as APFINITY, POP1880, 1881, 1840, 1450 and other resins. Then the American Exxon. Mitsui of Japan and Phillips of the United States have also produced MLLDPE. Such as Exxon's EX-CEED350D60, 350D65, Mitsui Petrochemical's E-VOLVE SP0540, SP2520, Philips' MPACT D143, D139 and so on. Since MLLDPE has good blendability and easy processability with LDPE and LLDPE, MLLDPE can be mixed in blown film or casting process, and the mixing ratio can be from 20% to 70%. Such films have good tensile strength, impact strength, good transparency, and good low-temperature heat-sealing and anti-contamination properties. The composite materials used as inner layers are widely used in frozen, refrigerated foods, shampoos, Oil, vinegar, soy sauce, detergent, etc. It can solve the packaging speed, breakage, leakage and penetration of the above products in the packaging production and transportation process.
4, cover film inner layer material
Liquid packaging cups for jelly, juice, yogurt, fruit milk, soup, etc. Bottle, the main material is HDPE. PP, PS, etc. The cover film of this package should consider both the shelf life and the heat seal strength between the cover film and the cup, and also consider the convenience of the consumer - easy tearability. To achieve this particularity, the inner layer material can only form an interfacial bond strength with the cup day, but cannot penetrate and fuse together completely. Modified EVA resins are generally used. Such as the US DuPont APPEEL53007. TOPCO L-3388 from Toyo, Japan, LOTRYL 20MA 08 from France, WT231 from HIRO.DINE, Japan, etc. The structure can be: PET/PE/HM, BOPA/PE/HM, PET/VMPET/PE/HM, PET/AL/PE/HM, paper/PE/AL/PE/HM. For the cover film and the bottom cup to be tightly closed, the material of the bottom cup is generally required to be consistent with the inner layer material of the cover film, so that the two materials are completely fused when heat-sealed. For example, HDPE cup, the inner layer of the cover film is: LDPE or EAA; PP cup, the inner layer of the cover film is CPP film; PET bottle, we have found a coated modified PET film as heat seal layer, Sealed PET bottles were obtained with satisfactory results.
5, co-extruded film
The film produced by blending a single layer of LDPE or LDPE with other resins has a single performance and cannot meet the requirements of packaging for the development of modern articles. Therefore, the co-extrusion film produced by co-extrusion blown film or co-extrusion casting equipment has improved overall performance. . For example, the mechanical strength, heat sealing performance, heat sealing temperature, barrier property, opening property, and anti-contamination property of the film are improved, and the processing cost is lowered, and it is widely used. Such as H layer co-extrusion blown film hot melt adhesive film: PE / HM, cable film PE / EAA, MLLDPE low temperature heat sealing film, EVA cover film and antistatic film, slip film. The H layer is co-extruded and cast co-extruded CPP, unmodified PP/heat-sealable PP, and the like. Three-layer, five-layer nylon co-extruded film, five-layer, seven-layer EVOH, and PVDC high-resistance separator are also being developed and widely used.
The development of inner film of composite flexible packaging materials, from LDPE, LLDPE, CPP, MLLDPE, to the large-scale use of co-extruded film, basically realizes packaging functionalization and individualization, and satisfies the quality, processing performance and transportation of packaging contents. ,Storage conditions. With the continuous introduction of new materials, the improvement of inner film production technology and equipment, the inner film of composite flexible packaging materials will be rapidly developed and promote food.
The development trend of China's flexible packaging industry In the packaging industry, flexible packaging has become one of the most important packaging forms for shelf sales with its brilliant colors, rich functions and diverse forms of expressiveness. The progress of the domestic soft packaging industry has greatly promoted the development of food, daily chemical and other industries. The development of these industries has further stimulated the demand for the flexible packaging market, which has enabled the flexible packaging industry to gain tremendous market momentum. With the development of functional flexible packaging materials and the continuous improvement of processing technology, flexible packaging is playing an increasingly important role in many fields. This article introduces you to the basic situation of the domestic flexible packaging industry.
(1) Equipment and technical level of flexible packaging industry
In recent years, with the advancement of technology and the development of the market, customers have continuously improved the quality and service requirements of products, and the competition among enterprises has intensified. Coupled with the great changes in the political, economic and social environment, the domestic flexible packaging industry has gradually become A fully competitive industry. The profit margins of the whole industry are getting smaller and smaller, and the loss-making enterprises are increasing. One after another, the once brilliant enterprises are on the road of brutal competition. The era of meager profit is coming to us with irreversible trends.
The domestic soft packaging industry has a history of more than 20 years. For more than 20 years, the domestic flexible packaging industry has grown from small to large and has developed rapidly. At present, it has reached a relatively mature stage, showing an obvious trend of grouping and scale. World-class printing companies are accelerating their development in China by means of absolute holding, new wholly-owned manufacturing companies and holding companies, and mergers and acquisitions of China's dominant enterprises. Domestic soft-package color printing companies are aware of the crisis and huge opportunities, and also use various methods to expand the scale of the industry and develop into the marginalization of the industry.
At present, there are about 400 imported gravure flexible packaging production lines in China, and nearly 1,000 domestic high-speed gravure flexible packaging production lines. The manufacturing level of these production lines is close to or reached the level of developed countries; the low-end narrow gravure flexible packaging production line does not count The number. In addition, in recent years, through the continuous efforts of our flexo printing workers, coupled with the world's most advanced laser direct plate making technology and high-quality inks, flexographic plates and other consumables, the quality of flexo-printed flexible packaging products is increasing, and applications are becoming more and more wide.
With the continuous improvement of the level of equipment and raw and auxiliary materials and the increasing experience of production, management and management, the technical level of China's flexible packaging industry has advanced by leaps and bounds, and the quality of products has been greatly improved. As far as the printing quality is concerned, the printing level of China's flexible packaging industry can be said to have reached a fairly high level, and the printing quality is much higher than that of similar products in developed countries and regions in Europe and America.
At present, the overall development level of the flexible packaging industry in mainland China is higher than that of Eastern European countries such as Russia, and higher than other countries in Asia except Japan and South Korea. The development level of the flexible packaging industry in South Korea and Taiwan Province is basically the same. The main gaps with the soft packaging industry in developed countries are reflected in product standards and medium and high-grade modern packaging materials, especially in the development and production of special and special functional packaging materials.
(II) Flexible packaging equipment manufacturing industry
China's gravure composite flexible packaging equipment manufacturing industry has only a decade of history. On the basis of the introduction of equipment, through digestion, absorption, imitation and independent development, great progress has been made in recent years. At present, China has been able to produce gravure printing machines, dry laminating machines, extrusion laminating machines, slitting machines and bag making speeds of 100 segments/minute or more with a printing speed of 300 m/min and a width of 1000 mm or more. Automatic bag making machine. At present, domestically produced equipment is mature in technology and supplies a large amount of equipment for the domestic soft packaging industry. A group of enterprises such as Shaanxi Northwest, Zhongshan Songde, Shuguang Machine and Shantou Huaying have almost completely occupied the domestic high-end gravure flexible packaging equipment. market.
In recent years, with the development of the domestic flexible packaging industry tends to be flat, the domestic flexible packaging machinery market has also become flat. The flexible packaging industry in many overseas regions is constantly evolving, so many flexible packaging equipment manufacturers are looking to overseas markets.
With excellent cost performance, China's equipment has strong market competitiveness in the international market, especially in Southeast Asia, West Asia and Northeast Asia. In addition, plate-making companies, film manufacturers, ink and adhesive manufacturers are also making efforts in overseas markets.
(3), flexible packaging film substrate
In recent years, China's flexible packaging film substrate industry has developed rapidly. Domestic flexible packaging film substrates such as BOPP, BOPET, BOPA, CPP, PE, VMPET, VMCPP can not only meet the needs of the domestic market, but also export to foreign markets.
BOPP is the most used material in the field of flexible packaging. It is widely used in food, medicine, tobacco and other fields due to its light weight, transparency, non-toxicity, moisture resistance, low gas permeability and high mechanical strength. The production of BOPP film in the past few years has a high profit, which has stimulated the rapid development of the BOPP film industry, resulting in a serious overcapacity in some areas; BOPET film has good flatness, excellent sealing, high temperature resistance, high tensile strength, transparency and gloss. Good quality and other advantages, the amount of use in the packaging market is rapidly increasing; BOPA film is widely used in the packaging of high-temperature cooking food, boiled food, vacuum food, and the production capacity of domestic BOPA film because of its special properties such as softness and puncture resistance. It is steadily improving.
Nowadays, some of the more advanced flexible packaging color printing factories continue to put forward new requirements for the printing performance and composite performance of film substrates, such as shallow screen printing performance, transparency, and composite strength. The requirements of BOPP heat sealing film are very different. Because there are many kinds of new and old packaging machines in China, the technical level is very different. No BOPP heat sealing film can run smoothly on all packaging machines. With the development of BOPP film industry, BOPP film has also been given many new features, resulting in some new market segments, such as ultra-thin BOPP film, high transparent BOPP film, high printing performance BOPP film, UV resistant BOPP film. , environmental protection and degradable BOPP film, anti-fogging BOPP film, BOPP color film, BOPP label film, BOPP printable shrink film, metallocene catalyst system BOPP film, high barrier BOPP film, BOPP synthetic paper, BOPP twist film. These have provided a good basis for BOPP film manufacturers to adopt differentiated strategies.
In addition, the film substrate manufacturers have seen a significant scale and group development trend, and gradually become more rational in the price competition, and have obtained more price discourse rights.
(4), flexible packaging printing ink
The currently used gravure inks are generally made of chlorinated polymers. In the ink production process, the chlorinated polymer needs to be dissolved by using a strong solvent (such as an aromatic solvent such as toluene), and toluene is also required to adjust the viscosity of the ink during the printing process. Today, chlorinated polymer ink systems are considered to be non-environmental products. Because the chlorofluorocarbons that are volatilized in production destroy the atmospheric ozone layer; the use of aromatic solvents such as toluene can cause harm to workers' health and safety during ink production and printing. In addition, solvent residue in packaging is another important issue that needs attention. Since an aromatic solvent such as toluene is a slow-drying solvent, it tends to remain in the dried ink layer, which may contaminate the contents of the package and cause odor.
The production of flexible packaging gravure inks is subject to numerous regulations, so the development and application of environmentally-friendly green gravure inks will become an inevitable trend. Zhejiang New Oriental Ink, Tianjin Toyo Ink, DIC Ink and other companies have become the first companies to obtain China Environmental Label Green Ink Product Certification. The environmentally friendly development of flexible packaging gravure inks is as follows.
(1) Reducing solvent residues in existing ink products.
This is mainly for BOPP film-specific inks. The main countermeasures are: use solvent-friendly binders and additives to maximize the volatilization of aromatic hydrocarbons. However, since the binder system itself determines that aromatic hydrocarbons cannot be eradicated, from an environmental point of view, this is a product that must be eliminated.
(2) No benzene type ink.
In theory, such inks do not contain aromatic hydrocarbon solvents, but the storage, transportation, manufacturing process and use of the raw materials will be more or less mixed with a small amount of aromatic hydrocarbon solvent.
(3) A benzene-free, ketone-free alcohol-soluble ink.
Due to stricter solvent residue requirements, various ink manufacturers have introduced alcohol-soluble inks. These inks do not contain aromatic hydrocarbons and ketone solvents. They contain only esters and alcohol solvents. They have low odor and high brightness. Their application will definitely improve the competitiveness of gravure printing in packaging and printing.
(4) Universal ink.
At present, the ink used by flexible packaging enterprises is basically an ink corresponding to a substrate, and the inks used in various substrates cannot be used universally, thereby causing an increase in ink inventory of flexible packaging enterprises, difficulty in management, many on-site operations, and difficulty in residual ink. Digestion and other issues. How to recycle the remaining ink is one of the important issues facing the flexible packaging gravure printing enterprises. Universal inks can effectively solve the above problems, and are suitable for a wide range of film materials, and can also bring benefits to the standardized management of color.
(5) Aqueous ink.
The water-based ink avoids the pollution of volatile organic substances, improves the printing environment, and is beneficial to human health. It is especially suitable for food packaging, food, medicine and other products with high hygienic requirements. In addition, it reduces the risk of fire caused by static electricity and flammable solvents, and reduces the solvent odor remaining on the printed surface. Water-based inks have been widely used in paper printing, but there are still a series of problems for film-based substrates. Only white ink has entered the scale application, and other color inks are gradually entering the market.
(5), composite adhesive
At present, the composite adhesives used in the domestic flexible packaging industry mainly include two-component polyurethane adhesives, water-soluble acrylic adhesives, water-soluble polyurethane adhesives, alcohol-soluble adhesives, and solvent-free adhesives. The development of China's flexible packaging industry is closely related to the technological progress of domestic two-component polyurethane adhesives. However, in recent years, under the impact of environmental protection, two-component polyurethane adhesives have been challenged as never before, showing the following development trends. .
1. Development and application of high-solids, low-viscosity, low-solvent residual composite adhesives Domestic binder manufacturers have matured and their technological development strength has been greatly enhanced. Some representatives such as Zhejiang New Oriental, Beijing Research Institute of Chemical Industry and Beijing Gaomeng Chemical have emerged. Sexual business.
At present, high solid content, low viscosity adhesives have become an important development direction of dry composite adhesives. At the same coating amount, the use of high solids binder can effectively reduce the amount of solvent used, and has the following advantages: reducing solvent consumption; reducing drying load, increasing production efficiency, reducing energy consumption; and reducing solvent residue. Previously, the two-component polyurethane adhesives had a solid content of 35% or 50%, which has now increased to 75% or 80%; a two-component polyurethane adhesive with a solids content of 75% accounted for 60% of the market share. The market share of 50% bicomponent polyurethane adhesives is shrinking, now less than 30%.
2. Development and application of water-based adhesives The advantages of water-based adhesives are that water replaces organic solvents, there is no potential danger of combustion and explosion, no pollution to the environment, no toxicity to operators, and low cost. However, such adhesives have poor coating properties and poor wettability to the composite substrate, resulting in low adhesion. At present, ordinary water-based adhesives are only suitable for some light-weight packaging, and for some of the more demanding material structures, the performance of the water-based adhesives is still to be further improved.
In 2007, water-based adhesives have been widely used, which benefited from the recognition of consumers, and also benefited the manufacturers' cultivation of the water-based adhesive market, and benefited from the continuous price of raw materials for two-component polyurethane adhesives. The rise in solvent-based adhesive costs.
3. Develop solvent-free adhesives
The solvent-free adhesive is basically composed of a two-component polyurethane adhesive, and the main agent and the curing agent have a high viscosity at room temperature, but still have fluidity and are semi-solid materials. The solvent-free composite process does not have organic waste gas emission problems, the equipment is simple, the energy consumption is small, the cost is reduced, the resources are saved, and the environment is protected, so it will be the main development direction of the future composite process. At present, most of the low-end composite flexible packaging can use solvent-free adhesives, but due to factors such as composite quality, solvent-free composite can not completely replace dry composite. From a long-term perspective, with the increasingly strict environmental regulations and the continuous development of the economy, the proportion of solvent-free adhesive products will continue to rise.
4. Develop and apply alcohol-soluble polyurethane adhesives.
The alcohol-soluble urethane adhesive can use ethanol as a diluent, and the solvent residue is usually less in the usual case, and the ethanol is cheap, which can effectively reduce the compounding cost. In addition, the alcohol-soluble urethane adhesive has good compatibility and adhesion to alcohol-soluble inks, and it can be aged at room temperature, eliminating the cost of curing. Because of these characteristics, alcohol-soluble polyurethane adhesives will gradually occupy a certain market share.
(6), gravure plate making
In recent years, due to the rapid development of the domestic packaging market and the rapid update of international gravure plate making equipment, China's gravure plate-making technology has developed rapidly, plate-making enterprises have blossomed everywhere, plate-making quality has been greatly improved, and the plate-making cycle has been shortened. The number of domestic electronic engraving machines has reached hundreds. In this regard, China has become the world's largest regional plate making base. With the continuous increase in the number of plate-making enterprises, the total production volume has risen correspondingly, the market division has become more detailed, and the price war has intensified, resulting in a sharp drop in corporate profits, and the plate-making price has dropped to a lower level. As a result, some large-scale gravure printing companies have turned to transfer printing plates, leather embossed plates, anti-counterfeiting plates and other fields.
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
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