Liangjian acrylic sheets, especially cast acrylic sheets, are widely used in bathtubs, sanitary ware, spas, and swimming pools due to their excellent transparency, durability, and moldability. Among various production methods, casting is considered the highest quality process for producing acrylic sheets.

This article will clearly outline the casting process of acrylic sheets, from raw materials to finished products.

What are Cast Acrylic Sheets?

Cast acrylic sheets are made by directly polymerizing methyl methacrylate (MMA) monomer in a mold. Unlike extruded acrylic sheets, cast sheets are formed naturally through a controlled chemical reaction, rather than through forced extrusion.

Compared to extruded acrylic, cast acrylic sheets have the following advantages:

Higher molecular weight

More uniform internal structure

Better chemical and heat resistance

Superior thermoforming and vacuum forming performance

Therefore, cast acrylic sheets are the preferred material for bathtubs and spa products.

Acrylic Sheet Casting Production Process

1. Raw Material Preparation (MMA Monomer)

The core raw material for cast acrylic sheets is high-purity MMA monomer. Before production, the raw materials must be carefully prepared, including:

Filtering to remove impurities

Precise formulation and proportion control

Moisture content control

Depending on the application requirements, other components may need to be added, such as:

Initiators to control the polymerization reaction

Stabilizers to improve weather resistance

Pigments or functional additives for coloring and UV protection

The quality of the raw materials directly affects transparency, strength, and long-term stability.

2. Mold Assembly and Cleaning

Cast acrylic sheets typically use a double-layer glass mold, consisting of:

Two high-strength tempered glass plates

Sealing gaskets to control the sheet thickness

Before casting, the mold must be thoroughly:

Cleaned

Dusted

Inspected to prevent bubble formation

Even minor contamination can lead to visible defects in the finished sheet.

3. Liquid Pouring

The prepared MMA liquid is slowly poured into the assembled mold. The key requirements at this stage include:

Controlled and uniform pouring speed

Prevention of air entrapment

Maintaining a level liquid surface

After filling, the mold is sealed and prepared for polymerization.

This step is also where the name "cast acrylic sheet" originates.

4. Polymerization and Temperature-Controlled Curing

The filled mold is placed in a temperature-controlled oven for polymerization. The curing process typically includes:

Low-temperature initiation

Medium-temperature reaction stabilization

High-temperature final curing

The entire process may take 10-24 hours or longer to ensure:

Complete polymerization of MMA

Minimization of internal stress

Uniform and stable sheet structure

Precise temperature control is crucial for the final product quality at this stage.

5. Demolding and Natural Cooling

After curing:

The mold is disassembled

The glass plates are separated

The acrylic sheet is removed

The sheet then undergoes natural cooling and stress relief to reduce the risk of deformation or cracking caused by temperature differences.

6. Cutting and Surface Treatment

According to customer requirements, the raw acrylic sheet can undergo the following processing:

Size cutting

Edge trimming

Protective film application

For high-end products, the following additional processes may also be included:

Surface polishing

Thickness calibration

Quality inspection and grading

This ensures that the acrylic sheet meets functional and aesthetic standards.

Main Advantages of Cast Acrylic Sheets

Compared to extruded acrylic sheets, cast acrylic offers the following advantages:

✔ Superior optical clarity (up to 92% light transmission)

✔ Excellent thermoforming and vacuum forming performance

✔ Wider thickness range

✔ Higher mechanical strength and durability

These characteristics make cast acrylic an ideal material for bathtubs, sanitary ware, and spa applications.

Why the Bathtub Industry Prefers Cast Acrylic

Bathtubs are exposed to:

Hot water

Continuous weight loads

Cleaning chemicals

Frequent temperature changes

Cast acrylic sheets have:

Low internal stress

High crack resistance

Smooth, repairable surface

Long-term dimensional stability

These characteristics make cast acrylic the preferred material for high-quality bathtubs.

Liangjian's acrylic sheet casting process is a precise manufacturing method that combines material science, temperature control, and production expertise. Each high-quality cast acrylic sheet is the result of rigorous raw material selection, controlled polymerization processes, and meticulous post-processing.

This meticulous manufacturing process ensures that the product delivers exceptional performance in bathtubs and other high-end sanitary ware applications.