I. Core Principles of Formulation Design

PVC roofing tiles need to meet four core requirements: 5-10 years of colorfastness for outdoor use, impact resistance without brittleness, no yellowing during high-temperature processing, and controllable cost. The formulation design follows three principles:

1. Weather Resistance First: Focusing on solving problems related to UV aging and decomposition in humid and hot environments;

2. Strength Suitability: Balancing rigidity (wind load resistance) and toughness (impact resistance);

3. Processing Synergy: Ensuring the formulation matches the extrusion/coating process, avoiding problems such as melt cracking and mold sticking.

II. Core Raw Material Selection and Proportion Optimization (Based on 100 parts PVC resin)

1. Main Resin and Filler System

- PVC Resin: SG-5 (K value 67) or SG-6 (K value 65)

- Filler: 30-50 parts of lightweight activated calcium carbonate (CaCO₃)

2. Weather Protection System (Crucial for Outdoor Use)

- UV Protection: UV absorber + light stabilizer

- Rutile titanium dioxide (TiO₂)

3. Processing and Stabilization System

- Heat Stabilizer:

- Environmentally friendly export scenarios: Calcium-zinc composite stabilizer, requiring the addition of β-diketone and phosphite auxiliary stabilizers;

- Cost-sensitive scenarios: 2.5-3.5 parts of lead salt stabilizer.

- Processing aids: 1.5-2.5 parts of ACR 401 to promote PVC plasticization, improve melt strength, and prevent surface flow marks and sharkskin during extrusion; for producing coated tiles, ACR 530 (higher melt strength) can be used.

- Lubricants:

- Internal Lubricant: Stearic Acid

- External Lubricant: PE Wax + High-Density Oxide Wax

4. Toughening System (Key to Impact Resistance)

- General Purpose: CPE

- High-End Purpose: MBS

III. Core Conclusions of Formulation Research

1. The key to PVC roofing tile formulation lies in "system synergy": stabilizers, lubricants, and processing aids must match the resin type and processing technology to avoid performance imbalance caused by excessive use of a single raw material;

2. Weather resistance is the core competitiveness of outdoor building materials. The combined use of UV absorbers and light stabilizers, along with ASA coating technology, can significantly extend the product's service life;

3. Cost optimization requires finding a balance between "filler addition amount" and "toughening/weather resistance system" to avoid blindly increasing CaCO₃, which can lead to a decline in product performance.