Acetate cellulose board (commonly referred to as CA board or celluloid board) is a high-end plastic board with excellent performance and wide applications. Its raw materials and production processes are very distinctive.

Below is a detailed analysis of the raw material composition of cellulose acetate sheet from three aspects: core raw materials, formula system, and brief process flow.

ONE、 Core Basic Raw Materials

The "skeleton" of cellulose acetate sheet is cellulose acetate resin, which is chemically modified from natural high molecular weight cellulose.

1. Source: Cellulose

Mainly from high-purity wood pulp or cotton short fibers. These are the most abundant natural polymers in nature, providing the basic skeleton of materials.

2. Chemical modification: esterification reaction

Cellulose reacts with acetic anhydride under the action of a catalyst (usually sulfuric acid), and the hydroxyl groups on the cellulose molecular chain are replaced by acetyl groups to produce cellulose acetate.

Key parameters: Combined with acid content or acetyl content. This determines the properties of cellulose acetate:

Cellulose diacetate: The binding acid content is about 53-56%. Good solubility, it is the main type for manufacturing boards, textile fibers, and films.

Cellulose triacetate: binding acid content>60%. It has better heat resistance and moisture resistance, and is mainly used as a polarizing film for liquid crystal displays.

TWO、 Complete formula system (the "soul" of the board)

Pure cellulose acetate resin is brittle and prone to decomposition, making it unsuitable for direct use. To produce boards with excellent toughness, gloss, processability, and stability, multiple additives must be added to form a complex formulation system. This is the core of the technical secrets of various manufacturers.

The main additives include:

1. Plasticizer (most critical, maximum dosage):

Function: Inserting between polymer chains, reducing intermolecular forces, making the material flexible, easy to process, and lowering melting temperature.

Common types:

Phthalates: such as dimethyl phthalate and diethyl phthalate. This is the most classic and commonly used type.

Phosphates: such as triphenyl phosphate. It has both plasticizing and flame retardant effects.

Citrate esters: such as acetyl tributyl citrate. Used as an environmentally friendly and non-toxic plasticizer.

The type and proportion of plasticizers directly affect the hardness, toughness, heat resistance, and weather resistance of the board.

2. Dyes and pigments:

Acetate cellulose sheet is known for its rich colors and extremely high transparency/transparency.

Dyes: Used to manufacture brightly colored and transparent boards. It needs to have excellent light resistance and good compatibility with CA.

Pigments/pastes: used to manufacture opaque, solid colored, or special effects (such as pearl or marble patterns) boards.

3. Stabilizers:

Heat stabilizer: prevents resin decomposition and discoloration during high-temperature processing (cellulose acetate has poor thermal stability). Commonly used metal soaps or organic stabilizers.

UV stabilizer: Improve the UV resistance of the board and prevent yellowing and brittleness after long-term use.

4. Lubricants and processing aids:

Improve the flowability of resin during extrusion or rolling processes, prevent adhesion to equipment, and make the surface of the board smoother.

THREE、 Brief process flow of sheet metal manufacturing (understanding how raw materials are converted)

1. Mixing: Dry cellulose acetate resin powder is thoroughly mixed with accurately measured plasticizers, colorants, stabilizers, etc. in a high-speed mixer to form a moist and uniform premix.

2. Plasticization and Rolling: The premix is completely plasticized by an extruder or mixer under heating and shearing, becoming a uniform "dough like" material. Then, it is pressed into a continuous sheet with the required thickness and smoothness through a multi roll rolling mill.

3. Maturity: The rolled sheet is left at a constant temperature for a period of time to release internal stress, stabilize the crystalline structure, and achieve optimal performance. This is a unique and crucial step for CA board.

4. Cutting and packaging: Finally, cut into pieces according to the requirements and package them before leaving the factory.

Main application areas

Glasses industry: The core material of high-end eyeglass frames, due to its lightness, good toughness, rich colors, warm luster, comfortable skin touch, and easy processing.

Crafts and fashion accessories: hair clips, combs, buttons, jewelry display stands, pen holders, etc.

Industrial design: tool handles, automotive interior parts, instrument panels, etc.

Professional fields: Drawing rulers, substrates for membrane switches, etc.