Types and Advantages of Open-Top Bottom-Gusset Bags

　　 Open-top square-bottom bag : Valve bags, commonly known as bottom-seal bags, are currently one of the most popular types of packaging bags worldwide. They are filled through a valve opening at the top or bottom using dedicated filling equipment. After the material is loaded, the bag is formed into a cubic shape. Key features of open-top, square-bottom valve bags include improved packaging efficiency, convenient transportation, high structural integrity, and a low breakage rate. Compared with conventional bags, they offer a range of unparalleled advantages in plastic-film packaging applications for chemical granules and powders, as well as agricultural products such as starch and fertilizers. For example: 1) Square-bottom valve bags have an aesthetically pleasing appearance and deliver high-quality printing; 2) Their robust construction enables them to withstand severe impacts and handling, thereby reducing losses caused by package rupture.

　　The open-mouth, flat-bottom bag is manufactured by extrusion-laminating composite resin, kraft paper, and woven fabric into a single integrated structure that serves as the base material. After the bottom panel is aligned and folded, an environmentally friendly adhesive is applied, followed by manual folding to form various types of sealed-top packaging bags. The bottom is then reinforced with kraft paper for added strength. Bag strength can be customized between one and six layers according to customer requirements, and printing is integrated directly into the bag-making process. A typical configuration is a square-bottom valve bag made of three layers of kraft paper plus one layer of PE film, providing excellent moisture and humidity resistance—and outstanding leak-proof performance!

　　 Open-top square-bottom bag Valve types: internal-valve and external-valve. Product features: fully eco-friendly and green; diverse material options to meet various packaging requirements; compliant with environmental protection and export packaging standards; suitable for food packaging; exquisite printing; aesthetically pleasing package design; ample packaging capacity; vertical packaging; ideal for automated filling by packaging machinery. Polypropylene-coated woven open-bottom square bags are developed on the basis of coated woven bags, with dimensions customizable according to customer specifications, and manufactured using hot-air welding technology to achieve either top-and-bottom sealing or sealing at the bag opening. Application scope: widely used for packaging powdered and granular products such as chemical raw materials, new building materials, high-tech materials, pharmaceutical additives, food additives, starch, dairy fats, plastics, and more. Square-bottom valve bags can be stacked and placed on pallets wrapped with stretch film, meeting international standards.

　　 Open-top square-bottom bag Key advantages: The use of open-top, square-bottom bags simplifies and reduces the physical effort required for many tasks. When loading goods, the contents can be gently kneaded from the inside to close the valve opening, achieving a secure seal. The square valve pocket is neatly sewn, leaving an opening for machine filling; packaged products are then fed into this opening under pneumatic or mechanical drive. Square valve bags include color-printed woven valve bags, paper–plastic composite valve bags, and kraft paper valve bags with a staple-type film closure. A standout feature of all these valve bags is that they are odorless, non-contaminating, and meet hygiene standards; moreover, thanks to the excellent printability of paper, graphics and text can be customized according to customer requirements. Valve-sealed paper bags made from such materials are highly convenient and flexible during flour packaging, enabling filling speeds to increase by up to three times, eliminating dust emissions and improving the working environment. Because the filled valve bag assumes a rectangular shape, it stacks easily and does not slide, allowing for a 10% increase in storage capacity under the same footprint while ensuring that handling operations do not compromise the cleanliness of operators’ work attire.