Tinplate Packaging Products, You Need to Know
Tinplate Packaging Products, You Need to Know These Basics
Metal tins—also known as tinplate boxes—are classified as auxiliary materials within the realm of cosmetic packaging. Their primary function is to safeguard the integrity of both the inner packaging and its contents, serving as the ideal support system for both flexible and rigid packaging formats.
Products definition
Tinplate—also known as tinned iron—is the common name for electro-plated tin-coated thin steel sheets.
Abbreviated in English as SPTE, it refers to cold-rolled, low-carbon thin steel sheets or strips that have been coated on both sides with commercially pure tin. The primary function of the tin coating is to prevent corrosion and rust. This material combines the strength and formability of steel with the corrosion resistance, solderability, and aesthetic appeal of tin within a single medium, characterized by its resistance to corrosion, non-toxicity, high strength, and excellent ductility.
Due to these inherent properties—specifically its superior ductility, oxidation resistance, printability, and durability—as well as its ability to be formed into various shapes and the ease with which it can be transported, tinplate has become a preferred choice for packaging applications.
Manufacture process
1.Raw materials
A. Base Materials
The raw materials we utilize include tinplate, matte-finish tin, galvanized iron, and base plate iron (commonly known as "black iron"); occasionally, we also employ aluminum. Auxiliary materials consist of copper wire, nitrogen gas, spray paints, liquefied gas, pallets, cardboard, strapping bands, stretch wrap, and similar items.
Tinplate is our most frequently used material; specifically, we typically utilize tinplate with a 2.8/2.8 coating weight and a hardness rating of 2.5. Common thicknesses range from 0.19 mm to 0.35 mm; iron materials exceeding this thickness cannot be printed upon. Matte-finish tin is also widely used—typically for products that do not require printing—as it is highly resistant to scratching; however, matte-finish tin carries a higher cost. Galvanized iron is generally reserved for products such as metal drums and is not used as frequently as other materials; its standard thicknesses are typically 0.28 mm and 0.30 mm. Base plate iron is typically utilized for products requiring double-sided printing.
B. Tinplate Structure
C. Tinplate Manufacturing Process
Coiled Soft Steel Sheet → Continuous Acid Pickling → Continuous Cold Rolling → Annealing → Electrolytic Cleaning → Electroplating → Reflowing → Chemical Treatment → Oiling → Inspection → Shearing → Grading → Packaging
2. Manufacturing Workflow
Color-Printed/Film-Laminated Tinplate → Shearing → Welding → Internal & External Seam Coating → Necking & Flanging → Seaming → Can Inspection → Full-Surface Spraying → Can Accumulation → Strapping → Film Wrapping → Finished Goods
3. Surface Treatment Process
Tin boxes feature a wide variety of surface finishes. These include the "white coating" effect (where the entire sheet of tinplate is painted white); "spot white printing" (where only a specific section of the tinplate is printed in white, leaving the remaining areas to retain the natural color of the tin); "gloss varnish" (typically applied to the interiors or bottoms of unprinted tin boxes or cans); and "gold varnish" (similarly applied to the interiors or bottoms of unprinted tin boxes or cans).
Other available effects include high-gloss finishes, matte finishes, and "gloss-over-matte" treatments (where specific sections of a tin can are coated with gloss varnish while others receive a matte finish). Furthermore, there are various specialized effects—such as rubber-feel oil, pearl-effect oil, crackle-effect oil, orange-peel texture oil, and tortoise-shell crackle oil—though these options are generally more expensive and, consequently, less frequently utilized.
4. Printing Processes
CMYK Printing
Also known as offset printing, this method utilizes four basic colors—red, yellow, blue, and black—mixed in varying proportions to reproduce a wide array of patterns and images. Unless a client specifies otherwise, our standard price quotes are based on four-color printing.
Spot Color Printing
This is a specialized printing technique that does not rely on the standard four-color process; instead, it involves the use of custom-mixed inks. Typically, clients provide a specific spot color reference number (e.g., a Pantone code), and during the printing process, the ink color is matched against a Pantone color guide to ensure accuracy. Generally, printing facilities charge an additional fee for spot color printing.
Engraving Process
It is divided into 2D engraving (flat engraving) and 3D engraving (three-dimensional engraving). 2D engraving is mostly used for logos and text, and the convex surfaces of the engravings are on the same horizontal line.
Product structure
1. Product Categories
By Shape: Rectangular cans, round cans, oval cans, octagonal cans, as well as various irregular shapes—such as cans with handles, heart-shaped boxes, etc.
By Structure: One-piece cans, two-piece cans, and three-piece cans.
2. Product Structural Components
A. Hinge Points
The component that connects the lid and the base of a tin box is known as the hinge.
Hinges fall into three categories: wire hinges, window hinges, and metal strip hinges. Of these three, the window hinge is the simplest and most economical, while the metal strip hinge is the most complex and most expensive.
B. Flared Base
Refers to a base where the bottom rim is rolled outward, wrapping around the lower body of the vessel.
C. Recessed Base
This refers to the bottom flange being folded inward, effectively tucking the body of the package underneath the base. The height of both the "gong" bottom and the "buckle" bottom can be adjusted.
D. Step
Refers to the small step on the lid.
E. Neckline
A raised ridge on the body of the can
3. Structural Description
A. One-piece can
Composed of a single piece of sheet metal (e.g., trays, metal plates, burner caps, etc.)
B. Two-piece cans:
The entire packaging container consists of two components: the can body and the lid. The can body is formed by subjecting a thin metal sheet to tensile deformation using a punch press and a deep-drawing die, thereby integrating the bottom and the body into a single seamless unit; hence, it is referred to as a "two-piece can."
Two-piece cans are classified in various ways: based on height, they are categorized as shallow-drawn or deep-drawn cans; based on the canning material, they are distinguished as aluminum or tinplate cans; and based on manufacturing technique, they are classified as drawn-and-ironed (D&I) cans or deep-drawn cans, among others. Please note that this type of two-piece can cannot be manufactured to excessive heights, typically not exceeding 40–50 mm. Furthermore, once the molds for these two-piece cans have been fabricated, their length and width dimensions cannot be subsequently altered.
Currently, the predominant type of metal container used for packaging is the aluminum two-piece can. These aluminum cans are manufactured using thin aluminum alloy sheets and employ a "drawn-and-ironed" (D&I) process during production; consequently, the thickness of the can wall is significantly thinner than that of the can bottom. When utilized for packaging beer, the substantial internal pressure within the can effectively compensates for the inherent lack of rigidity in the thin walls. Moreover, the superior gas barrier properties, light-blocking capabilities, and sealing integrity of these metal cans ensure the stable preservation of the beer's quality. It is precisely these inherent metallic characteristics that enable metal cans to accommodate high-speed filling operations—even when utilizing time-consuming methods such as isobaric filling.
C. Three-piece Can
A three-piece can is a type of metal packaging container formed from thin metal sheets through processes such as mechanical seaming, adhesive bonding, or resistance welding. It consists of three components—the can body, the bottom, and the lid—and is characterized by a seam on the can body, as well as rolled seams connecting the body to both the bottom and the lid.
Cosmetics Applications
Tin boxes are widely used in the cosmetics industry, such as for facial mask packaging, outer packaging boxes, and similar applications.
