Enhancing Paper Bag Strength through Informed Paper Selection

When it comes to crafting paper bags, a strategic selection of parameters can lead to an optimal choice that aligns both with your needs and budget. These parameters, including GSM, BF, COBB value, and paper finish (MG or MF), significantly impact the paper bag strength and overall quality.

GSM - The Misunderstood Metric

GSM, or grams per square meter, is often misconstrued as a sole measure of paper strength. However, its role is distinct. GSM quantifies the weight of a square meter of paper. Just as a heavyweight boxer might outlast a featherweight champion, GSM's relevance lies in specific paper classes. For paper bags, the range typically spans 35 to 150 GSM. Hand-made paper bags may lean towards 120+ GSM for ease of die-cutting, yet lower BF (bursting factor) papers in the 100 GSM range prove equally capable.

Bursting Factor - Unveiling Paper Bag Strength

Bursting Factor emerges as a key indicator of paper strength. It gauges the pressure at which paper ruptures. Beyond weight-bearing capacity, this factor unveils the weight threshold at which a paper bag might burst. Commonly, paper used for bags exhibits a BF range of 14-40. However, a BF above 30 is often more than sufficient.

COBB Value and Wet Strength - Weathering Dampness

COBB value, reflecting weight gain post-water immersion, often remains overlooked. Lower COBB values signify enhanced water resistance, preserving paper integrity under wet conditions. In moisture-prone locales like India, this parameter gains importance. Additionally, considering wet strength—paper's resistance alteration when wet—proves crucial. COBB values under 20 and wet strength exceeding 20 are favorable for bags accommodating cold items and slightly damp produce.

MG vs. MF - The Finish Dilemma

Machine Glazed (MG) and Machine Finished (MF) papers differ in their surface processing. MG undergoes calendaring for a smooth, glazed finish, amplifying print quality due to a more even ink base. MF, on the other hand, remains rough on both sides. MG's added shine can make it more expensive than MF.

Brightness - The Unseen Influence

Brightness denotes light reflection off paper surfaces, impacting not only printed materials but also the tactile quality of plain white paper. Unchecked brightness variations can lead to an unanticipated outcome. Striking a balance between cost and visual appeal is crucial.

Natural-Shade Paper - An Economic Option

Opting for natural-shade paper, which is slightly grayish brown, can yield cost savings. It's a feasible choice for those uninterested in printing on the bags.

Challenges and Consequences of Sourcing

The paper bag market faces a challenge due to big corporations compelling vendors to cut costs. This often leads to using rejected foreign stock lots. These batches lack consistency, making heavy metal migration tests unreliable for subsequent lots.

By strategically leveraging the parameters mentioned above, sourcing costs can decrease while adherence to specific guidelines ensures consistency. This empowers customers to harness the benefits of cost-efficiency without compromising on paper bag strength and quality.