Kraft Paper: How Much Do You Know About This Material?
Welcome to our blog on how to choose flexible packaging! By now, you may have used and thrown away hundreds of kraft paper packages. It is true that kraft paper is one of the most common forms of food packaging: from roasted coffee beans, to baked bread, to takeaway paper bags, kraft paper plays an important role in our daily lives.
How much do you know about Kraft paper? As a flexible packaging and paper bag solutions provider, let us introduce you to the environmentally friendly and magical world of kraft paper with a few keywords.
What is a kraft paper?
Kraft paper is a high-strength paper made from sulfate wood pulp (mostly coniferous wood) through a high-temperature and high-pressure pulping process. This process can retain the integrity of the wood pulp fibers to the greatest extent, giving it unique properties and advantages that are different from ordinary paper.
It is precisely these characteristics of high strength, good toughness, and environmental sustainability that make it a "jack of all trades" in the flexible packaging field.
What types of kraft paper are commonly used?
Different flexible packaging needs correspond to different types of kraft paper. Blindly choosing one type of paper can easily lead to suboptimal packaging or waste of costs. Based on MTPAK's project experience, it can be divided into two dimensions:
1. Classification by production process
According to different production processes, it can be divided into unbleached kraft paper, bleached kraft paper, greaseproof kraft paper, waterproof kraft paper, etc.
Unbleached kraft paper: It retains the natural color of wood pulp, creating a rustic, natural feel. In the flexible packaging industry, it's often used for products that pursue a natural, eco-friendly aesthetic, such as flexible packaging for organic produce, which more intuitively conveys the product's natural, green attributes to consumers.
Bleached kraft paper: It is typically white. To make the finished product smoother, bleached hardwood pulp is added to the mix, changing the color of the kraft paper. For example, by adding different wood pulps to the mix, it can appear black, gold, red, and other colors.
Greaseproof Kraft Paper: Kraft paper is coated with a food-grade, oil-proof coating. This makes it the preferred choice for flexible packaging of oily foods, such as fried chicken, French fries, and fried dough sticks. The oil-proof coating effectively blocks grease penetration, preventing oil stains from contaminating the packaging. It also preserves the taste and quality of the food, preventing it from softening or changing its flavor due to grease seepage.
Waterproof kraft paper: Treated with wax or PE coating, it possesses excellent water and moisture resistance. In the flexible packaging industry, it is primarily used for fresh food delivery packaging, such as seafood and meat. It effectively prevents blood seepage and maintains the integrity and cleanliness of the packaging. Takeout lunch boxes are also covered with waterproof kraft paper, which protects food from moisture while also providing a certain degree of insulation.
2. Classification by material
According to the different materials, it can be divided into recycled kraft paper, single-layer kraft paper, composite kraft paper, etc.
Recycled kraft paper: Kraft paper produced with recycled pulp made from recycled waste paper as the main raw material, with the recycled pulp usually accounting for more than 80%.
Single-layer kraft paper: In flexible packaging, it is often used to make envelopes and simple paper bags for small foods, such as the packaging of single loaves of bread in bakeries. It can provide basic protection without adding too much weight to the product, making it convenient to carry and sell.
Composite kraft paper: Laminating kraft paper with materials such as PE and aluminum foil greatly expands its application range. When combined with PE, its waterproof properties are significantly enhanced, making it suitable for use in flexible packaging bags for fresh food, preventing moisture seepage and spoilage. Combined with aluminum foil, it enhances barrier properties and is commonly used in packaging products such as coffee beans and milk powder that require high moisture and oxidation resistance, effectively extending the shelf life and preserving the flavor and quality of the product.
What is the difference between food grade kraft paper and ordinary kraft paper?
It is difficult to distinguish the two with the naked eye, and the paper needs to be illuminated by a fluorescent lamp to get the result. Usually, food-grade kraft paper does not contain fluorescent dyes and harmful additives, while ordinary kraft paper contains a small or large amount of fluorescent dyes.
If you happen to have a fluorescent pen at home, you can try using the fluorescent pen for a simple test.
In addition, ordinary kraft paper may be mixed with recycled pulp fibers, making it more suitable for products that do not come into contact with food, such as outer packaging and document bags.
FAQ
1. When choosing kraft paper, does a darker color mean better quality?
Not really. In fact, the color of kraft paper simply reflects the degree of bleaching and has nothing to do with its strength. For example, while unbleached kraft paper may be darker in color, some low-quality products may contain waste pulp, resulting in lower strength than high-purity bleached kraft paper.
MTPAK recommends prioritizing fiber content over color when choosing.
2. Is all Kraft paper suitable for direct food contact?
This depends on whether the product is labeled "food contact." Using industrial-grade kraft paper directly for flexible food packaging poses compliance risks.
MTPAK recommends requesting product certification and compliance reports from suppliers. All MTPAK food-grade kraft paper comes with test reports for inspection.
3. Can waterproof kraft paper be used to store high-temperature food?
The upper temperature limit for waterproof kraft paper is typically around 95°C. Using it to store hot food fresh out of the pot may cause the coating to melt or the paper to deform, which is harmful to health.
MTPAK recommends using special composite kraft paper that is resistant to high temperatures (e.g., above 120°C) or a thermal insulation lining for use in high-temperature environments.
Conclusion
Kraft paper is a packaging material that balances strength and brand recognition. Maximizing its advantages in flexible packaging requires choosing the right kraft paper and avoiding misapplications. Additionally, pay attention to color variations when purchasing kraft paper. We recommend seeing the product in person before purchasing.
If you're looking for higher-quality kraft paper packaging to boost your sales, please contact us. We'll provide comprehensive, one-stop service, from raw materials and design to production.
Email：account@mtpak.com
Contact us：https://mtpak.com/contact-mtpak