A.What is a bubble mailer?
Bubble Mailer is a polyethylene film (paper) and polyethylene bubble packing product. The HDPE or LDPE bubble film is primarily processed by film cutting, and then the bags are created and processed by a unique bag making machine for bubble film (hot drying and hot cutting bag making machine).
This article will define a bubble mailer, its various applications, and an in-depth look at the raw materials used in bubble mailers, as well as their manufacturing processes and procedures.
1.Bubble mailer characteristics:
The bubble bag possesses light weight, flexibility, shock resistance, waterproof, moisture resistance, corrosion resistance, and compression resistance because the middle layer of the bubble film is filled with air.
Shockproof, Compressive, and Elastic Waterproof, Moisture-proof, and Anti-corrosion
2.Usage and scope of application of bubble mailers:
Bubble mailer is a kind of flexible packaging product that is frequently used nowadays. The bubble film contains numerous small bubbles and is primarily used in the packaging of products that require buffering or shock protection during logistics and transportation, such as plastic, metal ceramic, glass, electronic, handicrafts, household appliances, kitchen utensils, precision instruments and other products that are afraid of being squeezed or crushed or fragile.
The principle is that the polyethylene film includes air to generate air bubbles to prevent the product from impact, ensuring that the product is protected when it is shaken, and also has the effect of thermal insulation, suitable for different product packaging or turnover in all walks of life!
3.The classification of bubble mailer:
Bubble mailers can be classified into three. These are：
I.Basedon the different facial film (paper), it can be divided into: kraft bubble mailer, co-extruded bubble mailer, pearlescent bubble mailer, pearlescent matte bubble mailer, metallic bubble mailer and clear bubble mailer.
II.Based on the different materials, there are：
PA Bubble Mailer
PA means (PE+PA). The bubble mailer made of PA has strong pressure and stretchability and is often used for heavyweight products, large products or products that need to be strengthened. Generally, these bubble mailers are made with valves, which can be inflated manually or automatically by machine.
HDPE Bubble Mailer
Bubble mailers made of HDPE(high-density polyethylene) have strong impact resistance. They are generally made without valves, but with an adhesive sealing.
LDPE Bubble Mailer
LDPE (low-density polyethylene) bubble mailers are transparent, soft to the touch, and visually appealing. This material is often formed into a valveless bubble mailer using an adhesive sealing method.
III. Based on the different surface treatments of facial film, it can be divided into a non-foaming bubble mailers and foaming bubble mailers.
4.Size of bubble mailer:
The common size of bubble mailer can refer to the poly mailer: https://packagengo.com/poly-mailer-buying-guide/
The thickness of the bubble mailer’s facial film (paper) varies depending on the product loaded. There are many sizes: 2mil, 2.5mil, 3mil, 4mil, 5mil, etc. The sizes and heights of the bubbles vary, for example, the diameter of the bubbles is 7mm, 8mm, 9mm, 10mm, etc., and the height of the bubbles is 3mm, 5mm, 8mm, and 10mm, etc. The gram weight of the bubble mailer varies due to the thickness of the face film (paper) and the size and height of the bubbles. The most commonly used sizes on the market are: 90g, 105g, 110g, 120g, 130g, 150g, 170g, 200g, etc.
The length of the bubble mailer = the length of the item to be loaded + height + 2cm
The width of the bubble mailer = the width of the item to be loaded + height + 2cm
The flap of the bubble mailer is usually 5cm
B. Raw materials of bubble mailer:
The raw materials of the bubble mailer are basically the same as the poly mailer. For details, please refer to https://packagengo.com/poly-mailer-buying-guide/. However, bubble mailer has a special raw material——aluminum foil.
Features of aluminum foil material:
1.Aluminum foil has high temperature resistance (121℃), low temperature resistance (-50℃). Metallic bubble mailers are more moisture-proof, heat-resistant and cold-resistant than ordinary bubble mailers.
2.Bags made of this material have great tear resistance and penetration resistance, it can better protect the product.
3.Metallic bubble mailers are rich in metal texture, the surface is smooth and bright, more beautiful than other materials.
C. The Production Process of Bubble Mailers
Below are the various steps to take in the production of poly mailers:
Step 1: Blow membrane
Blow membrane is a type of plastic processing process in which plastic particles are heated and melted and then blown into a film. The blow membrane process of bubble mailer is the same as that of poly mailer, typically using polymer extrusion molding tubular film blanks, in a better state of melt flow through high-pressure air will be blown into the required thickness of the tube film, after cooling and shaping into film. The membrane’s color can be changed. If no filler or color master batch is used, the membrane will be clear and the natural color of the raw material. Depending on the needs of the customer, several color master batches might be added.
Step 2: Printing
The printing process of bubble mailer is also the same as that of poly mailer. The bubble mailer’s printing pattern or text is customized to the customer’s specifications. It is divided into three types: single-color printing, two-color printing, and multi-color printing. When a customer customizes a pattern with multi-color, the printers and printing equipment requirements are extremely high. This necessitates not only experienced printers, but also a high level of machine precision. Otherwise, the impact of uneven printing overprint and ghosting will occur.
PNG has 2 computer-based 8-color automated overprinting printing machines with automatic scanners that can scan the printing patterns automatically. Once the scanned printing patterns are not overprinted, the equipment will automatically correct the deviation, allowing clients to satisfy their multi-color printing demands. Our printing equipment is the most advanced in the business, with excellent overprinting accuracy and the ability to reproduce 300-resolution patterns, and the printed completed pattern is clear and does not deviate from the design. Furthermore, our printers have many years of expertise in the field, are professional and experienced, and there is no issue in operating complex printing patterns!
Step 3: Composite
This is a unique connection between bubble mailers and poly mailers, yet it is the most crucial manufacturing link. It is the process of compositing the printed membrane and bubbles through a casting machine.
Step 4: Bag cutting and bag making
The last phase on the bubble mailer production line is bag cutting and bag making, which refers to cutting the composite bubble film into the finished product on the bag cutting machine according to the client’s preferred sizes, and gluing the release paper on the top of the seal. It should be firmly bonded, the glue should be evenly applied, the left and right sides should be centered, and no glue should be put to the corners to avoid the products from adhering together owing to the glue.
Our company has four fully – automated bag cutting machines that can manufacture up to 300,000 bubble bags per day, shortening delivery time significantly. If you have a large order, hand it over to PNG, and there is absolutely no problem with on-time delivery.
Step 5: Packaging
The inspected products are packed according to the customer’s requirements, and the outer box is a five-layer corrugated box specially used for export, and the box cannot be collapsed.
D. Factors to consider when designing bubble mailer.
When constructing a bubble mailer, there are a few things to consider:
1.The designer will establish the size of the completed bag before typesetting the bubble mailers. The length and breadth of the bubble mailers are usually off by around 5mm. Take note of the orientation of the bag’s opening, which is often separated into horizontal and vertical holes. To avoid reversing the text’s orientation, the openings should be oriented in the same way as the text. Additional horizontal apertures for bubble mailers are available, depending on whether the bag is to be flipped left or right, or front or back.
2.The width of the flap is the second factor to consider. When the bag length exceeds 20cm, the flap width is generally 5cm; when the bag length is less than 20cm, the flap width is 4cm. When the flap is brought over, its breadth should be bigger than its size (flap), preferably by more than 5mm. Otherwise, it tends to obscure the material on the opposite page, leaving the image incomplete.
3.Lines should be thicker than 0.2mm since they are easily blurred when printed if they are too thin.
4.The design file is ideally developed using a vector program such asAI, EPS, or PDF format, to achieve sharper lines. A bitmap is also acceptable, but the resolution should be approximately 300.
5.When calculating the size of the finished bubble mailer, the shrinkage of the bubble must be considered, especially in the sealing flap and the bottom folded part. After folding, the size of the flap and the finished product will appear smaller due to the difference between the inner and outer diameters. Under normal circumstances, these two positions should be lengthened by 1cm.
6.Avoid full-plate printing in the bubble mailer pattern design, or keep the printed pattern no more than 1.5cm away from both sides of the bubble mailer, because the sides of the bubble mailer must be heated and sealed. The printed pattern is readily destroyed when the edge is squeezed, resulting in an incomplete and unclear printed pattern.
PNG has a professional product R&D and design team that can assist you in designing products better and avoid affecting the finished product due to process problems in the actual production process.
7.The calculation of the finished product size of the bubble mailer must be taken into account that the bubble bag has a 1.5cm edge pressing on each side, reducing the real size of the product that can be loaded.
E.With regard to the quality control of bubble mailers, there are the following main points to note:
– Blown membrane thickness (usually 2 to 2.4 mil) and the reasonable deviation is about ± 0.1 mil
– Blown membrane with crystalline spots (the issue of crystalline spots depends on whether we use new or recycled material). The material filter should be replaced if there are crystal points.
– Blown membrane color (no obvious color difference, at least 90% similarity to the sample). Color masterbatch installed in the film blowing machine eliminates the problem of film blowing color differences, and the color masterbatch and raw materials are manufactured in a uniform proportion.
– The ink must be clear, non-blurred, non-stretching, non-gluing, and have high adherence. Tape can be used repeatedly without losing its color.
– Confirm whether the printed front text and pattern are centered, because the composite bubble film is in roll shape, and it is easy to produce positional deviation when replacing the roll film
– Check whether the film and the bubbles are combined firmly and cannot be cracked.
– If the foaming process is made, check whether there are no bubbles in some places on the front and back. Some non-foaming is caused by insufficient compound pressure and temperature adjustment, while others are caused by inadequate material and low gram weight of the film and bubbles.
– Whether the final bag’s size is accurate, the cut bag’s edge is tidy and free of burrs, the length, width, adhesive force of the glue, the material, and specifications of the release film are consistent with the customer’s requirements.
– The glue and the release paper must be tightly adhered, the glue must be applied evenly, the glue must be centered on the left and right, the two sides must not reach the end, and the glue must not be released. The product will stick together if the adhesive is applied on both sides.
– The front and back of the bag should be free of scratches. During bag cutting machine operation, the composite film is prone to scratches from the film guide roller and the film conveying platform.
– Check the bag’s sealing adhesive on a regular basis to guarantee that it cannot be opened.
– The blanking will appear bursting (whitening) phenomenon due to high pressure, but cracking will occur when the pressure and temperature are insufficient.
5.Edge sealing and sticking test:
The adhesive force of the bag making edge must be tested by QC, and it cannot be cracked in a straight line. The air bubbles inside the seal are destroyed once the seal is broken.
It must be carefully placed, covered in wrapping film, and the packing belt must be tight and secure.
Our company has a professional quality inspection team. Several sample inspections will be conducted during and after manufacturing. It will quickly stop and adjust if it does not match the quality criteria; all unqualified items will be rejected, and customers will be assured of the highest quality products.