Detailed Classification of Various Plastic Bags

With the ongoing refinement of the packaging industry, an increasing variety of plastic bags have emerged. Different scenarios and industries have vastly different requirements for plastic bag materials, toughness, sealability, temperature resistance, and other properties. The market offers a wide array of plastic bag types, and many procurement clients often struggle to understand the subtle differences between products, leading to improper material selection, packaging damage, non-compliance issues, and cost waste. As Qingdao Shimao, a professional plastic bag manufacturing factory, we are equipped with a full range of automated production equipment and support customization, mass production, and OEM/private-label processing. With years of deep experience in the packaging industry, this article will comprehensively break down common plastic bags from multiple dimensions—material, function, suitable scenarios, and product details—to help foreign trade companies, e-commerce businesses, and physical enterprises select the right products for their packaging needs.

I. PE Polyethylene Bags | The Most Versatile and Cost-Effective Basic Packaging

PE polyethylene plastic bags are currently the most widely used packaging material. They are non-toxic, odorless, moisture-proof, dust-proof, offer controllable toughness, and are cost-effective. Food-grade materials can directly contact goods. They are divided into three main subcategories—LDPE, HDPE, and LLDPE—each with significant performance differences. The industry-standard unit for thickness is "丝" (si), where 1 si = 0.01mm. Thickness directly determines load-bearing capacity and durability.

LDPE (Low-Density Polyethylene) Bags, commonly known as soft PE bags, feature high softness, high transparency, a warm texture, low rustling noise, and even gloss. Typical thickness ranges from 1.2 to 8 si. They can withstand low temperatures down to -25°C and heat resistance up to 90°C. Their excellent elongation makes them resistant to brittle cracking. Key advantages include food-safety compliance and good sealability, making them ideal for lightweight, delicate packaging. Common applications include food保鲜袋 (cling film bags), bread flat bags, takeaway delivery bags, garment dust covers, and jewelry storage bags. The main drawback is limited puncture resistance and load-bearing capacity, making them unsuitable for sharp or heavy items.

HDPE (High-Density Polyethylene) Bags, also known as hard PE bags, are stiff, rigid, and have a matte, milky-white appearance. They produce a crisp rustling sound when crumpled and have significantly higher rigidity and load-bearing capacity than standard soft PE. Typical thickness ranges from 0.8 to 5 si. Supermarket vest-style carrier bags and standard trash bags typically use 1.2–2 si thickness. They are resistant to acids, alkalis, moisture, and corrosion, making them suitable for both wet/dry waste and industrial material storage. These bags offer excellent cost-effectiveness and low mass-production costs, making them a universal choice for supermarkets, property management, and factories. The main disadvantage is poor transparency, so they are only suitable for basic storage and load-bearing packaging, not for product display.

LLDPE (Linear Low-Density Polyethylene) Bags are a thicker, functional material with properties between soft and hard PE. Their core advantage is exceptional tear resistance and puncture resistance—with double the toughness of standard PE at the same thickness. They can withstand low temperatures down to -40°C, making them suitable for demanding cold-chain environments. Typical thickened range is 6–20 si, primarily for heavy-duty packaging. Common uses include thickened courier bags, cold-chain fresh food packaging bags, hardware parts packaging bags, ton bag liners, and stretch wrap film. They effectively solve breakage issues with heavy or sharp items.

II. PP Polypropylene Bags | High-Transparency, Heat-Resistant, Premium Display Packaging

PP polypropylene plastic bags are known for high transparency, high gloss, and heat resistance, making them the top choice for premium product display packaging. They are divided into two types—soft CPP and rigid OPP—each with precise functional positioning for refined product packaging.

CPP (Cast Polypropylene) Soft Bags have the major advantages of heat resistance and heat-sealability, with a temperature range of 100–120°C. They are one of the few plastic films suitable for high-temperature retort and microwave heating. Food-grade CPP is grease-resistant and leak-proof. They are commonly used as inner liners for retort pouches, cooked-food packaging bags, and bread sealing bags, and can directly hold hot or cooked food safely and without odor. They are well-suited for the foodservice, bakery, and cooked-food processing industries.

OPP (Biaxially Oriented Polypropylene) Rigid Bags offer extremely high transparency, a mirror-like glossy finish, and excellent print quality for vivid, detailed graphics. They have a stiff, crisp feel and good shape retention, maximizing product visibility. They are widely used for shirt individual packaging bags, socks and jewelry packaging bags, stationery and card bags, and gift self-adhesive bags. It should be noted that this material is relatively brittle and prone to cracking at low temperatures, and it is not puncture-resistant. It is only suitable for flat, non-sharp lightweight products.

III. Multi-Layer Composite Functional Bags | Premium Protection, Freshness, and Sealing Professional Packaging

Single-layer plastic bags cannot simultaneously achieve oxygen-barrier, light-blocking, puncture-resistance, high-temperature resistance, and anti-corrosion functions. Multi-layer composite bags combine materials to compensate for the weaknesses of single materials. They are the core packaging choice for high-end food and precision industrial products, with PA/PE nylon vacuum bags being the most widely used.

PA/PE Composite Vacuum Bags feature a double-layer structure with an outer nylon layer and an inner food-grade PE layer, combining the best properties of both materials. They offer excellent puncture resistance, tensile strength, and oxygen/moisture barrier performance, with a temperature range of -40°C to 120°C. They are suitable for freezing, boiling, and vacuum sealing. They effectively block air, moisture, and bacteria, extending product shelf life. Common applications include vacuum-sealed packaging for dried snacks, meat products, precision hardware, and electronic components, providing outstanding waterproofing, rust-proofing, and anti-oxidation effects. Additionally, we can customize aluminum foil composite bags, light-blocking composite bags, and heavy-duty composite bags to meet special requirements in military, electronics, and deep-processed food industries.

IV. Factory Customization Advantages | Meeting Global Procurement Standardization Needs

As a source plastic bag manufacturer, we eliminate middleman markups and support customization across all plastic bag categories. We can adjust material thickness, size, printed logos, and add special features such as waterproofing, oil resistance, anti-static, and heat resistance according to client needs. From basic general-purpose bags and high-end display bags to heavy-duty functional bags and vacuum seal bags—our full product range covers all sizes and thicknesses. We offer stable mass-production capacity, fast delivery, and support for custom designs, samples, and OEM orders. We strictly control product details to prevent breakage, color differences, and poor sealing, providing global clients with a cost-effective one-stop packaging solution.