As in the picture above, it is a paper bag with clear window bag. The food packed in paper bags is very common in the market.
Key Features:
- High-Strength Kraft Paper: Natural, eco-friendly look that provides sturdiness and a premium texture.
- Clear Matte BOPP Window: Allows customers to easily see the product inside, enhancing visibility and trust.
- Food-Grade LDPE Inner Layer: Moisture-proof, grease-resistant, and safe for direct food contact.
- Box Bottom (Flat Bottom) Design: Helps the bag stand upright on shelves for maximum display effect.
Sustainable and Practical Packaging for 500g Food Box with Bottom Window Bag: Matte BOPP/Kraft Paper/LDPE Materials.
Ok, let’s get into a further explore of the materials of box bottom bag
Packaging Foil Materials:
The foil materials of this paper box bottom bag is formulated in 3 three layers, with details shown in the figure below
From the above graphic, you can learn that the material is made of 3 layers. Matte BOPP film works as the outside print layer, Kraft paper film working as the middle supportive and barrier layer, and finally, the LDPE film working as the inner sealing layer, Generally, we describe the foil structure as Matte BOPP/Kraft Paper/LDPE.
- With a matte finish effect on the outside, matte BOPP Filmworks as the outside print layer can improve the visual effect and add a fashionable touch to the packaging
- Kraft paper is one of the most commonly used materials to increase the eco-friendliness and sustainability of the packages. Kraft paper in natural color with a weight of 70gsm works as the intermediate layer. It is of good stiffness and a supportive layer
- LDPE film, with thickness adjustable against the requirements of the final package, works as the inner sealing layer
Matte BOPP or matte biaxially oriented polypropylene, is a polymer film with a matte finish that absorbs light instead of reflecting it. With a matte finish effect on the outside, matte BOPP film is widely used to improve visual effects and add a fashionable touch to the packaging.
It’s made up of multiple layers, including a polypropylene core and tie layers, and is often co-extruded with a skin copolymer layer on one or both sides.
The film is prepared through extrusion and biaxial orientation and can be made using either the tubular or tenter frame process.
Kraft paper is one of the most commonly used material to increase the eco-friendly and sustainability for the coffee packages. Due to the versatility, like light weight, heavy-duty, durable, tear-resistant, and low cost, it helps the roasters to create value-added packaging and a powerful marketing for their products.
As kraft paper is made from renewable resources, like plants and wood pulp, it is considered recyclable, renewable, biodegradable and compostable, which strengthens the green effect of the food bags
LDPE, means low density polyethylene film, it is environmentally friendly, low-cost, and low-energy. It is the most used inner sealing layer for the green tea bag. It is able to provide enough sealing strength and airtight property for the final packages.
Great Standup Effect
Kraft paper is a strong paper made from wood pulp that’s named after the German word kraft, which means “strength”. It’s made using the “Kraft” pulping process, which involves cooking wood chips under pressure to release cellulose and lignin, leaving behind solid wood pulp. So Kraft Paper can create enough standing effects for most products.
Of course, the thickness of a finished foil influences the standup effect of this nut pouch after being filled. The thickness of the LDPE film used in this foil laminate is 40 microns, with the overall thickness of this Matte BOPP18/Kraft Pafer70gsm /LDPE laminated foil around 140 microns.
The video below shows well the standup effect of the nut standup doypack.
Excellent Airtight Property for Zipperlock
This single-track plastic zipper is applied onto the kraft paper doy pack, with the back and front parts well melted to the inner layer of the doy pack. It enables the package to be repeatedly opened and closed with great airtight properties.
Here, we are going to open and close the zipperlock several times, and check if the air is easy to penetrate into or out of the package. Usually, we will apply a certain pressure on this closed zipper doypack, and check if the inflated doypack is easy to burst.
You are advised to have a further understanding of this test progress through the video below.
Mechanical Property
This reinforced laminated foil is achieved with great mechanical strength, with some standard items as below.
- Tensile Strength
- Sealing Strength
- Anti-puncture Strength
- Burst Impact Strength
- Anti-pressure Property
The above tests are performed against each order, on customer requirements, and you may check the exact values of this foil material in the Technical Date Sheet part of this post.
In our daily QC work, there is a more easy and reliable method to check if the bag strength is enough to meet the various conditions in the operations of filling, transport, loading and unloading, and distribution. We perform a drop test against each order, of course, the standard for this drop test should be decided against customer needs.
Here, we are going to fill 1000 grams of coffee beans into this kraft paper foil pouch, perform drops 5 times, and check if there is any breakage for the package.
Usually, the barrier performance of a multi-material laminate is evaluated by WVTR (short for water vapor transmission rate) and OTR (Oxygen Transmission Rate). The nut product will be kept away from these two elements to stay fresh as long as possible. However, please keep in mind that, the barrier property of this laminated foil is just a part of the measures taken to ensure the shelf life of nut products. The below table shows the typical value of the WVTR and OTR of this triplex foil laminate Matte BOPP/Kraft Paper/LDPE.
With the mocon O2/H2O/CO2 permeation tester equipped in our laboratory, we are able to keep a closer eye on the barrier performance of each laminate foil produced in our manufacturing plant.
Through the below table, you can easily find out the typical values of moisture vapor transmission rate and oxygen transmission rate of common substrate film materials.
Against this foil laminate MatteBOPP18/Kraft Paper70gsm/LDPE, actually, it is not high barrier performance, which can not protect the dry nuts products in a good state for a long time.
To ensure great protection of the dry nuts from oxygen, and moisture, usually, a layer of metallized polyester film or aluminum foil sheet is applied in the foil structure, with some common foil structures as below.
- Kraft Paper/VMPET/LDPE
- MatteBOPP/Kraft Paper/VMPET/LDPE
- Kraft Paper/ALU/LDPE
- MatteBOPP/Kraft Paper/ALU/LDPE
- Kraft Paper/ALU/PET/LDPE
This foil material proves to be working well for dry nuts and snack products distributed around the country.
Technical Data Sheet of 150 grams dry nut standing bag
Here, we attach the specification sheet of this 150 grams dry nut sachet based on foil laminateMatte BOPP18/Kraft Paper 70gsm/LDPE40.
More tests are included in this specification sheet with items available listed below.
More tests are included in this specification sheet with items available listed as below.
- Yield (grams per square meter)
- Tensile Strength (Mpa)
- Elongation Rate (%)
- Coefficient of friction, short as COF
- Solvents Left (mg/m2 )
- Sealing Strength (N/15mm)
- Sealing Conditions
- Bond Strength (N/15mm)
- Burst Strength (J)
- Anti-Puncture ability (N)
- Drop Test Ability (cm)
- Anti-pressure ability (kgs)
- Water Vapor Transmission Rate (g/m2/24hr)
- Oxygen Transmission Rate (cc/m2/24hr)
More Sustainable Materials Options
Along with the increasing burden of fossil-chemical polymer materials discarded into our environment, there is an unprecedented demand for sustainable packages which leads to a more eco-friendly activity of the business. Upon the recent investigation of the nut market, more and more consumers are more likely to purchase a product that acts toward environmental sustainability.
Compostable Packaging Materials
Compostable packaging materials are very similar to biodegradable materials. In most cases, people may not get a clear understanding of the difference between compostable and biodegradable. Generally speaking, compostable materials are based on biodegradable materials and when they break down, they will not cause harmful elements to the environment.
As to the materials used in our factory, the customers can just consider biodegradable equal to compostable.
The compostable packages are based on plant-based fibers like cellulose, or bio-mass like corn starch, cassava, or sugarcane. The resins derived from these resources are usually named bio-polymer, which can break down into inorganic elements under the functions of algae, bacteria, and other microorganisms.
Premium-quality compostable standup sachets and rolls are produced in our plant, which are intended to meet the particular requirements of every product. You may reach us for further ideas if you are interested in compostable packaging materials.
Fully Recyclable Mono Materials
Compared with the high cost of compostable foil materials, actually fully recyclable materials sachets and rolls are flooding the market for lightweight product packages in the market at much lower prices. Mono materials packages mean each layer of the multi-layer foil is made of the same resin, which can be easily processed in the human recycling system and reused for other applications. This recyclable materials sachet largely reduces the rate of plastic polymer film packages ending in landfills.
Come to the end, Please reach us if you have any questions regarding dry nut pouches. Good day.
