1. Wrapping: Use thinner flexible packaging materials and other composite flexible packaging materials to fully or partially wrap the packaged items.
Wrapping process: According to the operation mode of wrapping, it can be divided into manual operation, semi-automatic operation and fully automatic operation; according to the form of wrapping, it can be divided into folding wrapping and twisting wrapping. In addition, shrink packaging and stretch packaging also belong to the category of wrapping.
Packing process: according to the degree of packing automation, it is divided into manual packing and semi-automatic (taking blanks, unpacking, and sealing are manual operations) and fully automatic packing; Type packing method: drop packing process, hanging type packing, pinch packing process; horizontal packing method), wrapping packing process, inserting packing process (single inserting box, set-in box)
2. Blister packaging:
It refers to a packaging method in which the product is sealed between a blister formed by a transparent plastic sheet and a base plate (cardboard, plastic film or sheet, aluminum foil or their composite materials). (Typical process: sheet heating → film forming → filling items → substrate installation → heat sealing → edge trimming. Materials: plastic film sheets, substrates, coating materials.) Skin packaging: is to put the product in the can Air-permeable base plate made of cardboard or plastic sheet (film), covered with heat-softened plastic sheet, vacuumed through the base plate, so that the sheet (film) is tightly wrapped around the product, and its surroundings are sealed on the floor. A packaging method. (Technical process: the roll plastic film is clamped by the clamping frame, the heater above heats the film, the object is placed on the substrate, and is sent to the vacuum platform; the heater presses the softened film on the object, and starts Vacuuming; after vacuuming, the film is tightly adsorbed on the article and sealed with the substrate to form a complete package, the heater stops heating; the complete package is sent out. Equipment: substrate supply device, Plastic film extrusion head, vacuum device, seam cutter, cutting knife.)
The difference between blister packaging and skin packaging:
① Commodity protection: Blister packaging has barrier properties and can be vacuum packed; the substrate of skin packaging has vacuum holes and has no barrier properties.
②Packaging operation: Blister packaging is easy to realize automation or assembly line production, but it needs to replace the mold, which is suitable for small variety and large-volume packaging production; skin packaging is difficult to realize automation or assembly line production, and the production efficiency is low, but it does not need to replace the mold. It is suitable for the packaging production of multiple varieties and large quantities.
③Packaging cost: The packaging materials and packaging equipment of blister packaging are relatively expensive. For large and heavy items with small batches, the cost is higher due to the need to make molds; skin packaging is generally cheaper, but requires more labor. The cost is higher when mass packaging is produced.
④ Packaging effect: Blister packaging is more beautiful and can increase the value of the product; while skin packaging has a slightly inferior appearance due to the small vacuum holes on the substrate.
The difference between shrink wrap and stretch wrap:
⑴ adaptability to the product.
① Shrink packaging is not suitable for frozen or heat-resistant items, while stretch packaging is not subject to this restriction.
② Shrink wrapping can wrap items on the pallet, while stretch wrapping only wraps the items on the pallet.
(2) Adaptability to the circulation environment.
①From the point of view of the storage place of the package, the shrink packaging is not afraid of the sun and rain, and can be stored in the warehouse or in the open air, so it can save the warehouse area; the stretch packaging will relax due to the influence of sunlight or high temperature weather. Can be stored in warehouse.
② From the perspective of the moisture resistance and air permeability of the transport package, the shrink packaging is sealed on six sides, which has good moisture resistance and poor air permeability; stretch packaging generally only wraps around the four sides, and sometimes can also wrap the top surface, the overall moisture resistance Slightly worse, but good air permeability;
③ From the perspective of operating environment, shrink packaging should not be operated under low temperature conditions, while stretch packaging has no such restrictions.
⑶ equipment investment and packaging costs. Shrink packaging requires heat shrinking equipment, which has high equipment investment and maintenance costs, high energy consumption and material costs, and a long equipment payback period; stretch packaging does not require heating, and equipment investment and maintenance costs are low. Less, material consumption is 25% less than shrink wrap, and the payback period is shorter.
⑷In terms of packaging stress: shrink packaging is not easy to control, but it is relatively uniform; stretch packaging is easy to control, but the stress at the corrugated corners is too large and vulnerable.
(5) Stacking adaptability: Shrink packaging has good adaptability, stretch packaging has poor stacking property due to the self-adhesiveness of the film, the packages are easy to stick to each other, and are easy to tear during handling.
⑹ Requirements for stock film: Shrink packaging requires films of various thicknesses, while stretch packaging can be used for different items as long as there is a film of one thickness.
The spraying principle of the spray can: put liquid, cream or powder contents and propellant into an airtight container with a valve. Just spray it out and it's ready to use.
3. Filling process
According to the filling pressure, it can be divided into normal pressure filling (liquor, fruit wine, soy sauce, milk, medicine) pressure canning and vacuum filling (juice, jam, syrup, oil, pesticides). According to different measurement methods, it can be divided into liquid level filling and volume filling.
Atmospheric pressure filling (method: the lifting mechanism drags the packaging container upwards, and the mouth of the container contacts and presses the sealing device at the lower part of the filling valve to seal the container. The container continues to rise and open the filling valve to make the liquid storage tank The liquid material flows into the packaging container by its own weight; at the same time, the air in the container is discharged to the upper part of the liquid storage tank along the exhaust pipe; when the liquid level in the packaging container rises to the outlet of the exhaust pipe, the air in the container can no longer be discharged. The liquid that is continuously injected is slightly compressed. When the pressure balance is reached, the liquid level in the container remains at the specified liquid level. The lifting mechanism lowers the container, the filling valve loses pressure, and is automatically closed by the spring, and the liquid material in the exhaust pipe also drops into the container, and the filling is completed. The measurement of normal pressure filling is to use fixed liquid level filling) ,
Vacuum filling: pure vacuum filling (method: the packaging container is raised or the filling valve is lowered, the container mouth is in contact with the sealing device on the filling valve, and an airtight seal is established, then the valve is opened, the container is vacuumed, and the liquid is This pressure difference flows into the container through the suction pipe; when the liquid level rises to the vacuum nozzle, the liquid starts to rise along the vacuum pipe, so that the liquid level in the container remains unchanged. Excessive material forms overflow and backflow, and the overflowing material passes through The vacuum tube flows into the vacuum chamber and is sent back to the liquid storage tank by the liquid supply pump; after the filling is completed, the container is separated from the filling valve, and the valve is automatically closed under the action of the spring force), gravity vacuum filling (distilled alcohol, liquor, wine) ;Isobaric filling (before delivering the liquid material to the liquid storage tank, first pass compressed gas into the liquid storage tank, sterile gas or CO2 to keep the gas in the liquid storage tank at a certain pressure, the gas pressure needs to be equal to or Slightly higher than the saturation pressure of the CO2 dissolved in the liquid material to dissolve the CO2 in the beverage. When the lifting mechanism raises the packaging container to contact and seal the filling valve, the cock filling valve connects the air inlet pipe to the container. The gas in the air chamber of the liquid storage cylinder is pressed into the container along the intake pipe; when the air pressure is equal to the pressure of the container, the filling valve is rotated to connect the liquid inlet pipe and the exhaust pipe, and the liquid flows into the container by its own weight, and at the same time, the gas flows along the discharge pipe. The air pipe is discharged into the air chamber; when the liquid level rises and seals the outlet of the exhaust pipe, the liquid level stops rising, and the liquid rises along the exhaust pipe until it is equal to the liquid level of the liquid storage tank; at this time, the filling is automatically stopped and the filling The valve is closed, and the filling is finished; then, the container descends, and the liquid material in the exhaust pipe flows into the packaging container; only suitable for carbonated beverages, such as beer, soda, mineral water, champagne);
Pressure canning: fixed liquid level pressure canning (method: the liquid material in the liquid storage tank is pumped out by the material pump, and enters the packaging container through the filling valve; when the container is in contact with the filling valve and sealed, the filling valve is opened to carry out Filling; at the same time, the air in the container is discharged from the overflow pipe to the liquid storage tank, and the liquid level in the container is determined by the position of the overflow pipe at the neck of the container; when the liquid level rises to the mouth of the overflow pipe When the liquid level in the container no longer rises, the specified height is maintained, and the filling is completed. Until the container breaks away from the sealing device, the filling valve closes the filling port and overflow port, and the material stops flowing; filling liquid beverages containing less CO2 , such as some fruit wine); volumetric pressure canning (piston volumetric filling method: when the feed hole of the rotary valve is connected to the feed port of the hopper, the discharge hole is cut off from the feed pipe, and the piston moves to the left, The material is sucked into the metering chamber of the piston barrel; when the rotary valve rotates its discharge hole and the discharge pipe are connected, the feed hole is also cut off from the discharge hole, and the piston moves to the right, and the material is driven by the piston to pass through the bottom The material tube flows into the packaging container. The filling capacity is the volume of the metering chamber, and the capacity is determined by the stroke of the piston. Only when the packaging container lifts up the release ring on the feeding tube, the piston can move to the right; Paste, art paint), liquid level sensing filling (using sensing methods, such as extremely low air flow sensing devices, electronic sensing devices, to detect whether the container is in place and the height of the filling liquid level, and send out an appropriate signal opening and closing filling valve; paint); diaphragm volume filling (filling of various intravenous injections and injections); siphon filling (fruit wine, vinegar); timing filling; weighing filling.
4. Moisture-proof packaging: take certain protective measures to isolate the water vapor in the air from invading the contents, and avoid moisture, deterioration, mildew, decay, rust, etc.
The gas permeation amount per unit time and unit area is proportional to the concentration gradient, m=-D( ) water vapor permeability coefficient Pwv=(qwv*x)/[(p1-p2)A*t] qwv=mAt(qwv-water Vapor permeation, g; A-total area of plastic film packaging;
Moisture-proof packaging method:
The first category is the moisture-proof packaging method adopted to prevent the packaged items from absorbing or removing moisture and to ensure the stable quality of the items, that is, to use materials with good barrier properties for packaging to prevent the moisture of the packaged items from increasing or losing. (Food, also organic items such as fiber products and leather)
The second category is the moisture-proof packaging method used to protect the items from increasing moisture. The inside of the package adopts a certain drying method to absorb the moisture inside the package and the moisture infiltrated from the outside of the package, so as to slow down the increase of humidity inside the package and prolong the moisture-proof. The shelf life of the packaging. There are two drying methods: static drying method (use a certain amount of desiccant in the package to absorb the internal moisture, and its moisture-proof effect depends on the barrier property of the packaging material, the nature and quantity of the desiccant, and the size of the internal space of the package. The size is generally suitable for small packages and limited-term packages) and dynamic drying method (using dehumidification machinery to input dry and dehumidified air into the package to replace the humid air to control the relative humidity in the package and make the inside It is suitable for long-term packaging in large boxes, typically the packaged items are metals that are easy to rust, fertilizers that are easy to absorb moisture, cement, pesticides, gunpowder, etc.).
5. Vacuum packaging
(It is a packaging method that puts the product into an airtight packaging container, removes the air inside the container, makes the sealed container reach a predetermined vacuum degree, and then seals the packaging container.) Inflatable packaging into an airtight packaging container, evacuated or not, and then flushed into protective gas N2, CO2). Vacuum and air-filled packaging have the following characteristics: ① Food does not need to be heated or frozen, and no or less chemical preservatives are used, so it can have a longer shelf life, and the food flavor can be maintained better. ②The inflatable packaging is full and beautiful, which can overcome the characteristics of shrinkage, ugly shrinkage and easy mechanical damage of vacuum flexible packaging. ③ Compared with canning and freezing storage, the packaging materials and equipment are simpler, the operation is convenient, and the cost is less. Basic process elements: ① selection of gas components in packaging and determination of packaging storage temperature; ② selection of high barrier packaging materials and sealing of packaging containers; ③ selection of packaging methods and packaging machinery
The role of protective gas and storage temperature: Oxygen (the oxygen in the package will be less than 0.5% before it can kill the mold; fresh meat inflatable packaging should be filled with high concentration of oxygen 60%-80%, because oxygen can make Myoglobin is oxidized to oxidized myoglobin to maintain the bright red color of the meat; in the air-filled packaging of fresh fruits and vegetables, it is necessary to maintain a low concentration of oxygen (1%-6%)) Nitrogen, CO2, and lower storage temperature also reduce the respiration intensity of fruits and vegetables , The storage temperature is too low will cause "chilling injury".
Selection of vacuum inflatable packaging machine: chamber vacuum inflatable packaging machine
(Technical process: supply bags, load products → put into the chamber, the bag mouth faces the inflation port and lay flat on the heat seal strip → vacuumize → inflate (or not inflate) → heat seal → the chamber is ventilated to the atmosphere, and output the package pieces),
Vacuum Compensation Vacuum Inflatable Packaging Machine
（工艺过程：浅盘热吸塑成型→置入食品→覆盖膜→抽真空、充气、热封→切断→盒式包装件）
气流冲洗式充气包装机
(工艺过程：置入产品→覆膜、纵封（筒膜免）→气流冲洗→横封→切断→枕式包装件)
真空、充气包装工艺参数：
抽真空（一般要求腔室内真空度为10-30torr;抽真空后一般还有1.6%-2.2%的O2；抽真空时间据产品对真空度要求和包装容积，经实验确定）、充气（引入充气包装机的混合气体要有一定的压力。对于腔室式机，一般以0.15%-0.3%MPa为宜。一般充气后包装袋内压力以不大于0.12MPa为宜。充气时间也依袋容积而定，以袋饱满为原则）、热封合（热封合质量是真空充气包装密封性的重要保证。一般要求热封宽度稍大，这样热封强度较高。热风温度和热封时间可According to包装材料确定。一般用较高热封温度的复合材料。因为随生产连续进行，热封条温度升高，热封时间要及时调整）
真空充气包装的储存期：
包装外界氧气渗透穿过包装材料，达到包装内物品容许的吸氧量所经历的时间。气体渗透系数的表达式：Pg=(qg*d)/[(p1-p2)*A*t(Pg=P,g*10-11cm3*cm/cm2*s*101.325kPa,P,g为透气系数值；qg为气体渗透量cm3，d为塑料薄膜厚度，cm，p1-p2为包装薄膜两侧气体分压差kPa，A为包装薄膜表面积。真空充气包装的储存期:tθ=(qg*θ*d)/[Pg*θ(p1*θ-p2*θ)A]，θ为储存环境的温度。
6.无菌包装：
是在被包装物品、被包装容器（材料）和辅料、包装设备均无菌的情况下，在无菌环境中进行充填和封合的一种包装技术。采用的杀菌方法主要有加热杀菌（热杀菌）和非加热杀菌（冷杀菌）。被包装物品的灭菌技术：一种是巴式灭菌技术（将食品充填并密封于包装容器后，在低于100。C温度下保持一定时间。主要用于柑橘、苹果等果汁饮料、鲜奶、稀奶油、冰淇淋原料、乳酸饮料、发酵乳、低度酒、生啤酒、酱油、熏肉、火腿等食品的灭菌;其目的是尽可能地消灭病原微生物，巴式灭菌对象是酵母菌、霉菌、乳酸菌，巴氏灭菌装置主要有间歇式杀菌装置、连续式低温灭菌装置、微波加热灭菌装置；）另一种是超高温短时间灭菌技术（在135-150.C温度条件下、短时间对被包装食品进行灭菌处理，以灭杀包装容器内的细菌;广泛用于乳品、果汁饮料、豆奶、茶、酒、矿泉水等)微波加热灭菌、电阻加热灭菌（土豆、胡萝卜、苹果片及牛肉、鸡肉干）、高电压脉冲灭菌（牛奶、果汁）
Aseptic packaging system (package input part, package sterilization part, aseptic filling part, aseptic sealing part, package output part, etc.) and process: bottle aseptic packaging system and process (packaging bottle by The conveyor belt is sent into the machine, and then passes through the sterilization part 1, where the packaging bottles are sterilized by superheated steam. After the packaging bottles are sterilized, the temperature of the packaging bottles is lowered by the overpressure sterile air, and then in the Filling part 2 is filled with overpressure sterile air, filling the pre-sterilized and sterilized packaged items into bottles and cans, then adding the sterilized can lid at part 3, and filling the container with special equipment at part 4 The joint is welded, and finally, the package of the enclosed item is output by the conveyor belt), the cup forming aseptic packaging system and process (the bottom sheet is washed by a hydrogen peroxide tank, and then the hydrogen peroxide is decomposed by the action of a dryer , the sheet after passing through the dryer is softened and heated by the heater, and the container is formed at the former, and passes through the filling part, and the filled container enters the sealing part. At the same time, the aluminum foil cover material passes through the hydrogen peroxide liquid tank and goes out through the dryer Peroxygen compound, the container is sealed at the sealing part, cut off by the punching die, and finally the package is output by the conveyor belt.), plastic bag aseptic packaging system and aseptic process (use a sterile needle tube to sterilize the packaged items Filled into these pre-sterilized packaging bags, after the full bag is filled, it is sealed at 5 locations outside the filling point to complete the aseptic packaging, and then cut at 6 locations to output aseptic packages.
