New application of water-soluble PVA film in the production of waterproofing roll materials

Recently, water-soluble PVA film—used as a no-stripping protective liner—has found an innovative application in the field of waterproofing roll materials. It effectively addresses three key industry challenges: the labor-intensive installation of conventional waterproofing rolls, inadequate adhesion strength, and waste-related pollution—offering a completely new solution to enhance quality and reduce costs in construction waterproofing, while also supporting the industry’s shift toward greater environmental sustainability.

I. Core Role: Addressing Industry Challenges Across Three Areas

Thanks to its key property—solubility upon contact with water—the water-soluble PVA film eliminates the inherent drawbacks of traditional roll materials. Its primary value lies in the following three aspects:

1. Installation without removing the protective film, doubling efficiency: there is no need to manually peel off the protective film; the material can be laid directly onto a damp substrate or cement mortar, where the film automatically dissolves and disappears, eliminating the film-removal step and increasing installation speed by more than 50%. This is particularly well suited for work in basements, tunnels, and other damp, hard-to-reach spaces.

2. Strong adhesion and complete prevention of water infiltration: after the film dissolves, the asphalt mixture comes into direct contact with the substrate without any barriers, forming a “skin-like” bond; in combination with the reactive binder, it establishes a chemical bond with the cement hydration products, resulting in an adhesion strength that is 1–2 times higher than that achieved through conventional physical adhesion, thereby completely eliminating the risk of void formation and water infiltration.

3. Environmental friendliness, zero waste, and compliance with standards: the entire installation process generates no solid waste in the form of insulation film, ensuring a high level of site cleanliness, meeting the requirements of sustainable construction, and significantly reducing costs associated with waste removal and disposal.

II. Compatibility with Main Product Types

This technology is fully compatible with self-adhesive bituminous waterproofing roll materials for application on wet or dry substrates (non-curing, reaction-bonding), covering two major mature product systems:

Without a reinforcement layer (1.0–2.0 mm): the top surface consists of a protective layer made of PET film/cross-laminated mesh/aluminum foil; the intermediate layer is composed of modified bitumen/non-curing rubberized bitumen; the bottom surface is made of water-soluble PVA film.

Reinforced type (2.0–4.0 mm): the top surface is an insulating PE/PET film, the intermediate layer consists of a bitumen layer plus a polyester/fiberglass reinforcement layer and another bitumen layer, and the bottom surface is a composite water-soluble PVA film.

III. Key aspects of standardized installation using the wet-surface laying method

1. Substrate preparation: clean thoroughly; slight moisture is permissible, but no standing water should be present.

2. Initiation of the dissolution process: irrigating the base with water or applying a thin layer of cement mortar

3. Application and compaction: apply the water-soluble film with the adhesive side down, then compact it with a roller while removing air.

4. Dissolution and Adhesion: Within 5–15 minutes, the water-soluble film completely dissolves, and the asphalt and the substrate are fully bonded.

5. Joint sealing: completion of sealing the self-adhesive edges, forming a continuous waterproofing assembly

IV. Comparison of Key Advantages with Traditional Insulation Films

Comparison parameter: Traditional roll insulation films made of PET/PE; Water-soluble waterproofing roll materials made of PVA.

Lamination efficiency: Requires manual film removal, which is labor-intensive and prone to contamination. Does not require film removal; can be applied directly, increasing lamination efficiency by 50% or more.

Foundation Requirements: A dry substrate is required; bubbles easily form on a damp substrate. However, it can be applied to a damp substrate, demonstrating very high adaptability.

Adhesive properties: Physical adhesion, tendency for water penetration; complete adhesion plus chemical bonding, providing twice the protection against water penetration.

Environmental friendliness: A large amount of film waste is generated, placing a heavy burden on the environment. No solid waste is produced; environmentally friendly and compliant with regulations.

Adaptability to environmental conditions; Installation limitations at low temperatures; More convenient for installation at low temperatures.

V. Main Areas of Application

Waterproofing by applying a coating to a damp surface in underground structures: floor slabs/lateral basement walls, tunnels, pipelines, etc.

Fast installation on damp substrates in civil construction: roofs, kitchens, bathrooms, etc.

Anti-adhesion isolation for non-curing rubber-bitumen roll materials, installation without detachment

Temporary protection for pre-laid self-adhesive roll materials + requirement for dissolution upon contact with water

VI. Recommendations for Material Selection and Installation

1. It is preferable to use a water-soluble PVA film specifically designed for waterproofing, which must withstand temperatures of 90–150 °C, not melt during manufacturing, and dissolve rapidly upon contact with water.

2. During storage, strict measures must be taken to protect the product from moisture and maintain a dry environment to prevent premature dissolution and loss of film efficacy.

3. During installation, it is essential to ensure adequate moisture in the substrate; on a dry substrate, no dissolution occurs, which directly affects bond quality.

4. It is recommended to use a film with a thickness of 30–50 µm to achieve an optimal balance between dissolution rate and adhesive properties.