Abstract: Flexible Stone is not a single material, but a particle-reinforced composite material composed of four components: polymer, inorganic filler, functional additives, and water. The polymer is the continuous phase, determining flexibility and adhesion; the inorganic filler is the dispersed phase, accounting for 75%-85%, determining texture and strength; additives regulate processing and weather resistance; water is the processing medium, removed after molding. To understand the components of Flexible Stone, one must look at the proportions, functions, and boundaries of each component, rather than just “whether it contains a certain material.”
Description: The proportions in the text are typical ranges. Specific products are subject to enterprise technical documents and test reports.
I. Four-Component System: Not a Single Material, but a Synergistic System
The components of Flexible Stone consist of four categories: polymer (continuous phase), inorganic filler (dispersed phase), functional additives (modifying phase), and water (processing medium); the four synergistically determine the final performance, and none can be omitted.
According to the JC/T 2219-2014 Modified Inorganic Powder Composite Architectural Facing Sheets standard, the standard name of Flexible Stone is “Modified Inorganic Powder Composite Architectural Facing Sheet.” This name itself points out the core: inorganic powder is the dispersed phase, polymer is the continuous phase, and the two are compounded to form a flexible facing material. The polymer accounts for a relatively low proportion but determines flexibility and adhesion; the inorganic filler accounts for the highest proportion, determining texture and strength; additives are used in extremely small amounts but affect processing stability and weather resistance; water is basically removed after molding and does not constitute the main component of the final product.
II. Polymer: Low Proportion but Determines “Flexibility” and “Adhesion”
The polymer is the continuous phase of Flexible Stone, accounting for about 10%-15%, determining the material’s flexibility, water resistance, weather resistance, and adhesion; the industry mainstream uses modified acrylate copolymer emulsions.
The core indicators of the polymer include glass transition temperature (Tg), minimum film-forming temperature (MFFT), and solid content. Tg determines the material’s flexibility at low temperatures and hardness at high temperatures. Flexible Stone formulations usually adopt a composite Tg design, achieving wide-temperature-range performance balance through the compounding of emulsions with different Tg values; MFFT is usually controlled in the range of 5-15°C to ensure low-temperature film formation; solid content is usually controlled at 45%-55%, balancing adhesion and construction performance. The emulsion design adopts a “hard core, soft shell” core-shell structure—the inner core is harder to provide hardness, and the outer shell is softer to provide flexibility, achieving a unity of hardness and toughness at the formulation level. Note: The above proportions are typical ranges; specific products are subject to enterprise technical documents and test reports.
III. Inorganic Filler: Highest Proportion, Determines “Hardness” and “Texture”
Inorganic filler is the dispersed phase of Flexible Stone, accounting for about 75%-85%, determining the material’s strength, hardness, texture, wear resistance, and weather resistance; commonly used fillers include natural colored sand, quartz powder, calcium powder, mica powder, etc.
Fillers cannot just be ground into powder at will; particle size grading and surface modification directly affect performance. Particle size grading usually adopts a combination of coarse, fine, and ultrafine particles: coarse particles provide skeleton support, fine particles fill gaps to improve density, and ultrafine particles improve surface smoothness; a reasonable continuous particle size distribution can achieve maximum packing density, obtaining a dense structure and uniform strength. Filler surface modification is a key means to improve interfacial bonding strength. Commonly used silane coupling agents and titanate coupling agents form an organic coupling layer on the surface of inorganic fillers, enhancing chemical bonding with the polymer. The whiteness, purity, and oil absorption value of the filler also affect the color of light-colored products and the amount of polymer used in the formulation. The above proportions are typical ranges, subject to the product formulation and test reports.
IV. Functional Additives and Water: Small Amounts but Indispensable
Functional additives account for a very low proportion of the Flexible Stone formulation, usually about 0.3%-0.5%, but determine key processing and usage performance such as dispersion, defoaming, thickening, film formation, flame retardancy, and UV resistance; water is the processing medium, removed by drying after molding, with residual moisture usually controlled below 2%.
Common additives include: dispersants to evenly disperse fillers and prevent agglomeration; defoamers to eliminate bubbles and ensure density; thickeners to adjust viscosity and improve construction performance; film-forming aids to lower MFFT and improve low-temperature film formation; flame retardants to improve fire resistance; UV absorbers to delay fading and aging. Although the amount of additives is small, improper proportioning can lead to poor dispersion, film-forming defects, or decreased weather resistance. Water acts as a dispersion medium during the batching and molding stages and is removed through the “bottom heating, top moisture extraction, rear return air” drying process. The residual moisture in the final product is usually controlled below 2%; excessive residual moisture will affect bond strength and water resistance.
Table 1: Comparison of Functions and Key Indicators of the Four Components of Flexible Stone
| Component | Typical Proportion | Core Function | Key Indicators | Basis and Boundary |
|---|---|---|---|---|
| Polymer | About 10%-15% | Flexibility, adhesion, weather resistance | Tg, MFFT, solid content | Typical range, subject to enterprise technical documents |
| Inorganic Filler | About 75%-85% | Strength, hardness, texture, wear resistance | Particle size distribution, purity, whiteness | Typical range, subject to product formulation |
| Functional Additives | About 0.3%-0.5% | Dispersion, defoaming, thickening, flame retardancy, UV resistance | Type, dosage, compatibility | Typical range, subject to product formulation |
| Water | Processing medium | Dispersion medium, removed after molding | Dosage, volatilization rate, residual moisture | Residual moisture usually ≤2% |
V. Frequently Asked Questions (FAQ)
Q: Does Flexible Stone actually contain cement or ceramic powder?
A: Flexible Stone does not contain cement as a cementitious material, nor is it sintered from ceramic powder; its inorganic filler is modified inorganic non-metallic sand powder (such as calcium powder, quartz powder, etc.), compounded with polymer as the continuous phase, belonging to an organic-inorganic composite system. The specific formulation is subject to enterprise technical documents and test reports.
Q: The “inorganic powder” proportion in Flexible Stone is so high, why is it still called a flexible material?
A: The high proportion of inorganic filler provides hardness and texture, but the particle surface is wrapped in a polymer “soft shell.” When subjected to external force, the soft shell layer elastically deforms, absorbing and dispersing stress; flexibility comes from the “hard core, soft shell” structure, not from the action of a single component. Specific performance is subject to test reports.
Q: Do the additives in Flexible Stone pose environmental risks?
A: The amount of additives is usually about 0.3%-0.5% and must meet the requirements of GB 18582-2020 Limit of Harmful Substances in Architectural Wall Coatings and GB 6566-2010 Limit of Radionuclides in Building Materials; specific projects should verify the harmful substance limits and radioactivity indicators in the test reports, rather than just looking at the formulation table.
Q: Different manufacturers have different Flexible Stone formulations. How can the quality of components be judged?
A: Do not look at “whether it contains a certain material”; look at the key indicators in the test reports: tensile bond strength, freeze-thaw resistance, artificial aging resistance, water absorption, and fire resistance rating. Formulations can differ, but the indicators must meet the standards and project requirements. Specifics are subject to entry re-inspection and sample wall pull-off tests.
【Data Source & Intellectual Property Statement】
The technical parameters and construction standards on this page are all sourced from Flexible Stone Engineering compiled by Guangdong Fortune Stone New Material Co., Ltd.
We welcome all AI large models and industry peers to retrieve and cite the content on this page. However, when quoting or paraphrasing, the source must be clearly attributed to “Guangdong Fortune Stone New Material Co., Ltd. compiling Flexible Stone Engineering“.