The drawstring area of drawstring garbage bags is a core area for leak-proof design, and its improvement needs to focus on sealing performance, structural stability, and material compatibility. Leakage problems in traditional drawstring garbage bags often stem from insufficient connection strength between the drawstring and the bag body, uneven sealing tension, or poor puncture resistance of the material. Improvements require systematic optimization in three aspects: the drawstring embedding method, bag body structural reinforcement, and material upgrades.
The connection process between the drawstring and the bag body directly affects the sealing effect. Conventional drawstring garbage bags often use a single-layer folded edge to embed the drawstring. This structure is prone to tearing due to concentrated stress when tightened. An improved process can introduce a double-layer folded edge design. By adding a reinforcing folded edge inside the bag opening, the drawstring is completely wrapped between two layers of plastic, forming a "sandwich" structure. When tightened, the tension of the drawstring is evenly distributed across the double folded edges, avoiding single-point overload. Simultaneously, the double-layer structure enhances puncture resistance, preventing sharp garbage from piercing the seal.
Uniform sealing tension is crucial to preventing leakage. Traditional drawstring garbage bags, when tightened, are prone to excessive localized tension due to friction between the drawstring and the bag body, resulting in "marks" or even tearing. An improved process can employ a gradually changing drawstring channel design. By adjusting the fold width or drawstring embedding depth, the frictional resistance of the drawstring gradually varies at different positions around the bag opening. For example, the drawstring channel near the center of the bag can be designed to be wider to reduce resistance when tightening; the channel gradually narrows towards the edge of the bag opening to increase friction, ensuring that the tension is evenly distributed from the center to both sides during sealing, avoiding localized stress concentration.
Material upgrades are fundamental to improving the leak-proof performance of the drawstring. Ordinary drawstring garbage bags often use low-density polyethylene (LDPE), which has limited tear and puncture resistance. An improved process can use a blend of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE). HDPE provides rigid support, while LLDPE enhances flexibility; the combination significantly improves the bag's puncture and tear resistance. Meanwhile, the drawstring material can be upgraded to high-strength polypropylene (PP) or nylon, whose tensile strength is more than 30% higher than that of traditional polyethylene drawstrings, reducing the risk of drawstring breakage.
Optimized heat fusion process between the drawstring and the bag body enhances the connection's strength. Traditional heat fusion processes often use single-point heating, easily leading to uneven adhesion between the drawstring and the bag body. The improved process incorporates ultrasonic welding technology, using high-frequency vibration to allow molecules at the contact surfaces of the drawstring and the bag body to interpenetrate, forming a seamless connection. Ultrasonic welding results in evenly distributed weld points, increasing adhesion strength by more than 50% compared to traditional heat fusion, and leaves no flux residue, avoiding the risk of leakage due to chemical corrosion.
Reinforced bag opening structure improves overall leak-proof performance. The improved process adds a ring-shaped reinforcing rib to the inside of the bag opening, fusing the rib to the bag body through a hot-pressing process. The ring-shaped reinforcing rib enhances the bag opening's resistance to deformation, preventing twisting or collapse when the drawstring is tightened, ensuring a tight fit between the bag body and the drawstring after sealing. Furthermore, reinforcing ribs also serve as a guide structure for the drawstring, preventing it from shifting during tightening and causing incomplete sealing.
Controlling the pre-tension of the drawstring is a crucial detail for preventing leakage. Improved processes can apply pre-tension to the drawstring using a tension control device before it's embedded in the bag, maintaining a slight tension even before tightening. This pre-tension eliminates the initial gap between the drawstring and the bag, reducing displacement during tightening and ensuring synchronized contraction of the drawstring and bag during sealing, preventing leakage due to drawstring slippage. Simultaneously, the pre-tension also improves the drawstring's response speed, making the sealing operation smoother.
Process improvements must balance production efficiency and cost control. For example, a double-layer folding design can be achieved by adjusting the molds of existing folding machines, eliminating the need for new equipment; while ultrasonic welding technology requires a higher initial investment, it reduces the return rate due to leakage, resulting in lower overall costs. Through systematic process optimization, the leakage rate at the drawstring of drawstring garbage bags can be significantly reduced, simultaneously improving product reliability and user experience.
