Polyvinyl alcohol (PVOH/PVA) is a versatile, water-soluble synthetic polymer widely specified for its strong film-forming capability, high tensile binder strength, and resistance to oils, greases, and organic solvents. The primary performance determinants for PVOH resins are the degree of polymerization (which directly dictates solution viscosity) and the degree of hydrolysis (the mole fraction of residual acetate groups replaced by hydroxyl groups).
To address the processing limits of standard homopolymers—such as gelation under shear or high viscosity at high solids loading—modern formulations incorporate functional copolymer modifications. These modifications optimize dissolution kinetics, suppress foaming, and preserve rheological stability during long-term storage.
1.Comprehensive Elvanol PVA Series Technical Specifications
The physical and chemical specifications for the specialized Elvanol series are summarized below:
| Grade | Viscosity (cP, 4% @ 20°C) | Hydrolysis (mol%) | pH | Ash Content (wt%, Na₂O) | Key Polymer Characteristic |
| Elvanol 71-30 | 27.0 – 33.0 | 99.5 | 5.0 – 7.0 | ≤ 0.7% | Standard medium viscosity, fully hydrolyzed homopolymer |
| Elvanol 90-50 | 11.6 – 15.4 | 99.5 | 5.0 – 7.0 | ≤ 0.7% | Low viscosity, fully hydrolyzed homopolymer |
| Elvanol T-25 | 24.0 – 32.0 | 99.5 | 5.0 – 7.0 | ≤ 0.7% | Non-foaming, medium-viscosity warp sizing copolymer |
| Elvanol T-66 | 11.6 – 15.4 | 99.5 | 5.0 – 7.0 | ≤ 0.7% | Low viscosity, high-flux recovery warp sizing copolymer |
| Elvanol 80-18 | 17.0 – 23.0 | 99.5 | 5.0 – 7.0 | ≤ 0.7% | Alkaline-soluble, medium viscosity copolymer |
| Elvanol 85-82 | 25.0 – 32.0 | 99.5 | 5.0 – 7.0 | ≤ 0.7% | Rheologically stable, medium viscosity copolymer |
| Elvanol 75-15 | 11.6 – 15.4 | 99.5 | 5.0 – 7.0 | ≤ 0.7% | Medium-low viscosity, high barrier copolymer |
Note: All listed grades maintain Volatiles < 5.0 wt% and Residual Methanol < 1.0 wt%.
2. Key Industry Application Sectors
A. Textile Warp Sizing & Desizing Recovery Systems
In high-speed weaving of synthetic and natural spun yarns (such as polyester/cotton blends), maintaining yarn cohesion without causing loom shedding or drop-wire contamination is critical.
Elvanol T-25: Specifically developed for spun yarn warp sizing, this non-foaming copolymer maintains high weaving efficiency even under low-humidity conditions. It allows lower add-on rates when formulated with starch, reducing loom shedding and eliminating the need for enzyme desizing.
Elvanol T-66: Engineered for medium-to-high pressure slashers, T-66 exhibits lower viscosity than T-25. This lower viscosity allows formulations with higher solid concentration, superior yarn splitting in the leasing section, and drastically enhanced membrane flux rates during ultrafiltration PVOH recovery.
Elvanol 80-18: Features accelerated solubility in alkaline wash solutions, enabling easy desizing while minimizing process foam during wet treatment.
B. Paper Sizing, Pigment Binding & Barrier Packaging
Surface sizing and metering press applications demand controlled rheology to prevent misting and boundary layer breakdown.
Elvanol 71-30: The industry standard for medium-viscosity fully hydrolyzed PVOH. It delivers greaseproof properties and high oxygen barrier performance, making it widely used in size presses, calender stacks, and boric acid-tackified formulations.
Elvanol 90-50: Designed for high-speed metering size presses operating in excess of 1500 meters per minute. It provides film strength comparable to 71-30 while maintaining a low viscosity profile similar to starches, allowing higher solids formulations.
Elvanol 75-15: Offers high barrier protection against grease and gas transmission in medium-low viscosity coating systems, demonstrating excellent compatibility when co-formulated with starch.
C. Compounded Adhesives & Rheological Stability
Concentrated solution storage often leads to structural association of hydroxyl groups, resulting in unwanted viscosity spikes.
Elvanol 85-82: A unique medium-viscosity copolymer that resists retrogradation (viscosity increase over time) even at ambient or sub-ambient storage temperatures and higher solids concentration. It provides oil and solvent resistance alongside high bond strength, making it ideal for compounded adhesives, boric acid crosslinked systems, and wood glue formulations.
3. Summary Selection Protocol
High Line-Speed Paper Coating (>1500 m/min): Select Elvanol 90-50 (Low viscosity, high solids capability).
Ultrafiltration PVOH Recovery in Textiles: Select Elvanol T-66 (High permeate flux, easy desizing).
Cold-Climate / Long-Shelf-Life Adhesives: Select Elvanol 85-82 (Resists viscosity growth at sub-ambient temperatures).
Greaseproof Barrier Packaging with Starch: Select Elvanol 75-15 (High compatibility, medium-low viscosity).
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