Packaging has been the need of people from early time for marketing, storing, transporting, preserve foods, goods, products… in all industries. However, not everyone knows how plastic bags are produced?
Hanoi Plastic Bag Jsc produces plastic bags from materials HDPE, LDPE, LLDPE with many different products: t-shirt bag, t-shirt bags on roll, food bags, freezer bags, blockhead bag, wicket bag, bags on roll and luxurious plastic bags: soft loop handle plastic bags?, rigid plastic handle bags, drawstring bags, tri fold handle plastic bags, wave top bags. HANOI PLASTIC BAG JSC always use 100% virgin resins to make the best quality bags: strong, smooth and nice appearance.
Munufacturing process of plastic bags
There are 6 steps:
Step 1: Planning and designing
Planning and Designing of plastic bags or film. Hanoi Plastic Bag Jsc have a team of well trained designers to help market your company on printed bags perfectly. After get specifications of customers and usage of bags, we will decide percentage of the raw materials used for the product suitably.
All our materials are certified safe for food contact and meet standard requirements of EU and US.
Step 2: Materials Blending
All materials for producing plastic bags are chosen and mixed well in blending machine include virgin polyethylene resin (HDPE mixed with LLDPE, LDPE mixed with LLDPE, HDPE mixed with MDPE, LLDPE…).
There are also some additives mixed in the materials depend on customer requirements for their bags which we can do:
EPI, D2W, P life, Reverte or Biocom 1-2% to make the bags biodegradable and destroyed easily in the environment.
Masterbatch: 3-7% to make the bag color become white, blue, orange, yellow, green, black or red …
Anti-static (1-2%) to prevent the plastic layers from sticking together specially to help LDPE bags LLDPE bags open easily.
Ultra violet inhibitor (UVI) to protect the plastic from ultra-violet radiation. This additive is very useful in agriculture plastic cover.
If customers need the bags at cheaper prices, we will put few percent of additive materials such as CaCO3 (calcium carbonate) or and recycle materials to reduce bag cost. At this case, we can add an additive called impact modifier to make bags strong.
For food plastic bags as freezer bags, transparent plastic bags no handle, flat poly bag, polythene bags, blockhead bag, wicket bag, bags on roll and luxurious plastic bags for famous brand names egg: soft loop handle plastic bags, rigid plastic handle bags, drawstring bags, tri fold handle plastic bags, wave top bags we always use 100% virgin resins to make the best quality bags: strong, smooth and nice appearance.
Step 3: Blowing film or extruding film
After well-blending, the mixture will be treated into molten form at high suitable temperature for each polyethylene resin. It goes out at the shape of a bubble full of cool air that comes from the air ring, then blow in to plastic rolls. The step is very important because it can affect the strength, thickness consistence & transparency of the film. The bubble goes through cooling tower of 25 – 35 feet tall.
If plastic bags print simple from 1-4 colors totally in 2 sides, it can be printed together when extruding, it is called inline print. For luxury shopping bags print more than 4 colors or print complicated image, the plastic rolls will be moved to other specialized machine to print, it is called offline print.
All the materials will be put into extruding machine to make big plastic film roll. In this step, our workers or QC staff must control the bag rolls in correct thickness as customers require, equal thickness in the bag film and smooth appearance.
Step 4: Printing
Printing is mainly used for shopping bags which many companies could customize printing image with their logo, brand name, information about products. When getting orders with printing image, we will order printing plates and put into printing machines then print the plastic poly bags. Images are analyzed into different colors; and printing will be controlled by technicians if the bags need print many colors or printing images are difficult.
HANOI PLASTIC BAG JSC can print gravure and flexo for plastic bags. It is best to use gravure printing for shopping bags with natural and complicated images. For simple print or small quantity of plastic bag, people prefer flexo printing.
With the most modern printer and experienced technicians, HANOI PLASTIC BAG JSC can print plastic bags or plastic film perfect 100% ink coverage from 1 color until 12 colors (sometimes up to 16 colors), print CMYK with very complicated images which no company in Vietnam can do it.
The process is considered the most difficult cause ability and experiences of workers and technicians are the most important factor in order to make shopping bags printed nicely and perfectly. Level of each manufacturer is impressed by such the printing process.
Step 5: Cutting and sealing
In this step, side gussets, bottom gussets will be made. In this step, the heat temperature, the speed of machine will decide the strength & the appearance of the seal. The cut-out part of die cut bag, patch handle bag, t-shirt bag will be collected & recycled for Plastic Poly garbage bag.
The plastic rolls are put into cutting workshop to make it into different shapes and different handles. Hanoi Plastic Bag have a lot of different cutting machines both automatic and manual available to make different handles: T-shirt, t-shirt on roll, die cut, soft loop, patch handle, rigid, clip loop, tri fold, wave top, drawstring, draw tape, blockhead, wicket, zipper. The handles create different bag name such as t-shirt bags, t-shirt bags on roll, die cut plastic bag, soft loop plastic bag, patch handle plastic bags, rigid handle plastic bag, clip loop plastic bag, tri fold handle plastic bag, wave top bag, drawstring plastic bag, draw tape plastic bag, blockhead plastic bag, wicket bag, zipper bag.
For Luxury bags such as Clip loop Plastic bag, Rigid handle plastic bag, Soft loop bag, Tri fold handle bag Drawstring handle bag, etc they are usually required some manual steps which cannot be implemented by automatic machine. Our workers have to sew the handles and insert cardboard in bag bottom or top to make the shopping bags strong and in a good shape (customized to customer’s requirement) or punching the hole. They are called Luxury plastic bags or Luxury bags.
Hanoi Plastic Bag JSC always has over 250 workers to make handmade plastic bags to meet various demands of clients in our manual workshop.
Step 6: Packaging
The finished plastic bags will be packed as customer’s demand, Example: 20 pcs – 1000 pcs of plastic bags can be either packed in clear or printed outer bags before putting into export carton and ready for shipment. Especially Quality Control (QC) of Hanoi Plastic Bag JSC is very strict, our workers and technicians are trained carefully before they work. Moreover, everyday, there are 3-4 QC staffs for each process will be responsible to ensure products in each production process is correct and followed as exactly as client’s requestand then move to next the process. We now have over 30 professional QCs in total.
To have a through look into the whole process of manufacturing plastic bags, please go to our website: / to see the videos, pictures of each process and machines and details information about all types of plastic poly bags. You can choose to buy suitable plastic bags wholesale at reasonable prices.