KURARAY POVAL

The core of polyvinyl alcohol (PVA) performance lies in its degree of hydrolysis. The 88 Series PVA, which is partially hydrolyzed (usually around 87.0 to 89.0 mol%), differs from the fully hydrolyzed 99 Series in that it provides better flexibility, interfacial activity, and water solubility that can be adjusted. When PVA is partially hydrolyzed, about 11% to 13% of vinyl acetate groups (-OAc) are kept in the molecular chain. Because of these hydrophobic groups, the 88 Series PVA acts as an amphiphilic substance with high interfacial activity, unlike the 99 Series. Because of this, it works well as a protective colloid in emulsion polymerization and as a flexible base for strong adhesives and coatings with specific functions.     1. Molecular Structure Determines Function: Amphiphilicity and Protective Colloid Mechanism 1.1  Amphiphilicity Due to Hydrophobic-Hydrophilic Balance Partially hydrolyzed 88 series PVA molecular chains possess two functional groups with vastly different polarities: Hydrophilic groups: A large number of hydroxyl groups (-OH). Hydrophobic groups: A small number of evenly distributed vinyl acetate groups (-OAc). This structure makes PVA a highly effective high-molecular-weight surfactant or protective colloid. When dissolved in water, the molecular chains adsorb at the water-oil (monomer) interface, with the hydrophobic groups tending to embed into the oil phase, while the hydrophilic groups extend toward the water phase. This unique arrangement forms a stable, high-molecular-weight physical barrier (i.e., a protective steric barrier) around the oil phase particles, effectively preventing aggregation of emulsion particles during polymerization, storage, or mechanical shear, and is the core mechanism for ensuring emulsion stability. 1.2 Reduced Crystallinity and Improved Water Solubility Unlike the highly regular structure of the 99 series, the irregular distribution of vinyl acetate groups on the molecular chain disrupts the regular packing of PVA molecules, resulting in: Reduced crystallinity: The proportion of crystalline regions decreases, weakening the hydrogen bond network. Improved cold-water solubility: Lower crystallinity allows water molecules to more easily penetrate and disrupt the amorphous region structure. Therefore, 88 series PVA can dissolve quickly or even completely at lower temperatures (typically 40°C to 60°C), greatly simplifying dissolution operations during formulation and production.   2. Effect of Degree of Polymerization on Rheological Properties and Stability Given a consistent level of partial hydrolysis, the key differences between different PVA grades are mainly in their average degree of polymerization (DP) or molecular weight (MW). The DP has a direct impact on the viscosity of the PVA solution, the thickness of the steric barrier layer, and how the emulsion ultimately performs. The refined positioning of ElephChem's 88 series grades: ElephChem PVA Average degree of polymerization Average molecular weight Core application positioning 2688 / 2488 2400~2650 118000~130000 High molecular weight: Provides the strongest steric protection and is used in emulsion polymerizations requiring the highest stability (such as high-performance VAE emulsions). 2088 / 1788 1700~2100 84000~104000 General purpose: Balances viscosity and protection for general-purpose PVAc and VAE emulsions and adhesives. 1792 1700~1800 54000~60000 Medium-low molecular weight: Suitable for specialty water-soluble fibers and viscosity-sensitive coating systems. 0588 / 0488 420~650 21000~32000 Ultra-low molecular weight: Minimal effect on solution viscosity, suitable for inks, inkjet coatings, or as a co-stabilizer in emulsions. High degree of polymerization (Polyvinyl Alcohol 2688 / Polyvinyl Alcohol 2488): Long molecular chains provide a stronger steric hindrance. In emulsion polymerization, long chains help distribute and stabilize monomer droplets and polymer particles, which is needed for high-solids, high-viscosity emulsions. Ultra-low degree of polymerization (Polyvinyl Alcohol 0488 / Polyvinyl Alcohol 0588): These stabilizers function similarly to small-molecule emulsifiers, but provide improved polymer adhesion. Their low viscosity allows them to be used in high-solids coatings and slurry systems without affecting the rheological properties of the final product.   3. Analysis of Key Industrial Applications of Partially Hydrolyzed 88 Series PVA The interfacial activity and controllable water solubility of the 88 series PVAs give them core competitiveness in the fine chemicals, adhesives, and specialty materials sectors: 3.1 Emulsion Polymerization Industry: Stabilizers and Protective Colloids This is the core and irreplaceable application of the 88 series PVAs. It is widely used in the polymerization of monomers such as vinyl acetate (VAc), acrylates, and styrene-acrylates, and is a key additive in the manufacture of PVAc, VAE, and acrylate emulsions. Mechanism: 88 Series PVA acts as a protective colloid, not only stabilizing the emulsion during the initial polymerization phase but, more importantly, determining the freeze-thaw resistance, mechanical shear stability, and rewettability of the final emulsion. Applications: Architectural coating emulsions (such as interior wall latex paint), wood adhesives (white latex), textile nonwoven adhesives, carpet adhesives, etc. 3.2 Water-Solubility and Functional Films/Fibers The low crystallinity of partially hydrolyzed PVA makes it easier to dissolve quickly in cold water, making it a preferred environmentally friendly packaging material. Water-Soluble Packaging Film: Used for quantitative packaging of products such as pesticides, dyes, detergents, and laundry detergent beads. Upon application of water, the film quickly dissolves, releasing the contents, providing both convenience and environmental friendliness. Water-Soluble Fiber: Used in the textile industry as temporary support yarn or "sacrificial" yarn. After the fabric is finished, the PVA fibers dissolve in warm water, leaving behind a fabric with a special openwork or structural effect. 3.3 Adhesive and Coating Systems Adhesives: Due to the retention of hydrophobic groups in the molecular chain, 88-series PVA has better affinity and adhesion to certain hydrophobic surfaces and organic materials than 99-series PVA. It is widely used in specialty paper adhesives and rewettable adhesives (such as postage stamp adhesives). Specialty Coatings: Ultra-low molecular weight grades (such as 0488) can be used as ink-receiving coating additives for inkjet printing paper, providing excellent pigment binding and fast drying properties without significantly increasing coating viscosity. 3.4 Other Fine Chemical Applications Suspension Polymerization Dispersant: Used in the suspension polymerization of PVC resins, it helps control the size, porosity, and density of PVC particles, which is crucial to the processing properties of PVC resins. Ceramic Binder: Used as a temporary binder for bonding ceramics before molding and sintering. After sintering, it can be completely burned and vaporized, leaving no residue.   4. Conclusion: Continuous Innovation in Partially Hydrolyzed 88 Series PVA ElephChem partially hydrolyzed 88 Series PVA takes full advantage of both hydrophilic and hydrophobic elements in its molecular structure. This allows for careful control during emulsion polymerization and affects how well it sticks and dissolves in water. If the 99 Series is the "rebar" of structural materials, then the 88 Series is the "stabilizer" and "flexibility controller" of fine chemical systems. Partially hydrolyzed 88 Series PVA is still critical to the growth of modern fine chemicals and sustainable materials. This is due to the continued expansion of markets, like those for green water-based coatings, good emulsions, and biodegradable packaging, along with PVA's special interfacial chemistry and grade system.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

Polyvinyl alcohol (PVA) is a water-soluble synthetic polymer with excellent film-forming properties, surface activity, and strong adhesion to inorganic and cellulosic materials. Global annual PVA production is approximately 1.05 million tons, with Japan producing approximately 300,000 tons. Approximately 14,100 tons of this is used as a paper processing chemical, a surface sizing agent for plain paper, a sizing agent for coated and coated paper, a fluorescent brightener, an inkjet ink absorber, an adhesive for inorganic fillers, and a silicone sealant for release paper.   The paper business faces challenges like using different types of wood pulp and faster, bigger machines for making paper and printing. Because of this, they need better water-soluble polymers with special features. These polymers are important for making fancy specialty papers and papers used in tech. To adapt to these fundamental changes in the papermaking industry, Kuraray Japan has developed and mastered the properties of modified PVA with novel properties. This article will focus on two specialty PVA: the silanol-modified "R-series PVA" and the high-barrier "Exceval PVA" with the introduction of special hydrophobic groups. The two types will be discussed, along with their properties and applications in paper processing additives.   2. PVA Properties and Dissolution Methods Industrially, PVA is produced by polymerizing and then saponifying polyvinyl acetate. Its fundamental properties depend on its degree of polymerization and saponification. Most commercially available PVAs had a degree of polymerization of 200 to 4000 and a degree of saponification of 30% to 99.9% by mole fraction. The main varieties of PVA produced by Kuraray (Kuraray PVA) are shown in Tables 1 and 2.   3. Specialty Kuraray PVA To date, Kuraray has produced a variety of Kuraray PVAs with varying degrees of polymerization and saponification, which are used in a wide range of applications. As demand grows for better PVA and more varied uses, just tweaking the polymerization and saponification degrees isn't enough anymore. So, Kuraray PVA now comes with special groups added to give it extra function.   This article will introduce two types of functionalized PVA: the "R-series PVA," modified with silanol groups, and the "Exceval PVA (Exceval HR-3010)," which incorporates special hydrophobic groups for high barrier properties.   3.1 Silanol-Modified R-series PVA The R-series is a modified PVA with silanol groups. Table 3 lists the quality standards for the R-series products.     3.2 High Barrier Exceval PVA Exceval PVA is a PVA containing special hydrophobic groups. The introduction of hydrophobic groups enhances the crystallinity of the solid polymer, resolving the dilemma of achieving both high water resistance and stable aqueous solution viscosity, which is difficult to achieve with standard PVA. The use of PVA is increasing annually. PVA is usually used as a stabilizer in adhesives that need to resist water. But, when used in food packaging films, PVA doesn't block oxygen well when it's humid. Exceval PVA is also being developed as an improved material. In coated paper applications, Exceval PVA has also been successfully used when higher water resistance than PVA is required.   This article reports on the results of a new application study for Exceval PVA, specifically its use as an oil-resistant agent in food packaging. The product specifications of the Exceval PVA used in this study are shown in Table 4.   Table 5 shows that coating with Exceval PVA RS-2117 achieves air resistance roughly equivalent to that achieved with partially saponified PVA-217, while significantly reducing water absorption. Paper coated with partially saponified PVA exhibits higher air resistance. This is because the highly hydrophobic, partially saponified PVA has a lower surface tension in aqueous solution, inhibiting penetration into the paper. However, partially saponified PVA suffers from a significant reduction in water resistance. While Exceval PVA, modified with a special hydrophobic group, is fully saponified, it still exhibits the same permeability as partially saponified PVA, offering both improved water resistance and air impermeability.   R-series PVA contains highly reactive silanol groups, which improve adhesion to various inorganic materials. Using the R-series in inkjet media reduces the amount of polyvinyl alcohol used as a binder for silica particles, improving print quality. Even without a crosslinker, the R-series provides high water resistance. Exceval PVA is a modified, hydrophobic polyvinyl alcohol that offers excellent water resistance and gas barrier properties under high humidity conditions. The lower air permeability of coated paper provides a higher barrier to oils and greases than fully water-soluble polyvinyl alcohol, a property further enhanced when used with flake minerals. Exceval is now FDA-registered as safe for contact with food, opening doors for its use in food packaging paper.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

We used partially alcoholysis PVA-217SB (PVA080-22 & PVA1780) and high-efficiency environmentally friendly pulp together, and added a certain proportion of starch. We conducted experiments on several polyester-cotton varieties, which not only significantly improved the pulp shaft quality, but also greatly reduced the pulp cost.   Pulp performance: The chemical structure of PVA varies depending on the degree of alcoholysis. PVA with an alcoholysis degree of 99.6% is fully alcoholysis, like the PVA-1799 (PVA 100-27) we usually work with. On the other hand, PVA with an alcoholysis degree of 88% is partially alcoholysis, such as PVA-1788 (PVA 088-20) and PVA-217SB. The fully alcoholysis PVA mainly has hydroxyl groups in its structure, whereas the partially alcoholysis version contains some ester groups along with hydroxyl groups. This difference makes their performance quite distinct. For example, when mixing partially hydrolyzed PVA with completely hydrolyzed PVA and starch, the starch ratios needed aren't too different between the two. Generally, it should not exceed 70%, that is, the starch to PVA mixing ratio is generally about 7:3, in order to obtain a slurry with good miscibility. Runli's eco-friendly slurry is a milky white liquid that has over 98% effective ingredients. It has a viscosity of 2 to 8 mPa·s at 20℃ and a pH level between 7.5 and 8.5. This slurry flows well, has good elasticity, strong adhesion, mixes easily with other slurries and additives, and it's simple to remove after use.     Summary: (1) From the trial, tracking, and test analysis of Runli slurry and partially hydrolyzed PVA, we found that the slurry flow rate is stable and it is not easy to form sizing skin at low temperature. The thousandth reel is smooth, the sizing yarn feels smooth, and there is less regenerated hairiness. (2) The new sizing yarn indicators are way better than the old formula. We’ve seen a big drop in loom breakage and a solid increase in the good axis rate and loom efficiency. (3) The use of Runli sizing agent and partially alcoholysis PVA (PVA-217SB) sizing agent has greatly reduced the sizing cost.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com  

Ultrafiltration membranes are super popular for separating different substances. You can find them in areas like oil processing, textiles, biopharmaceuticals, food production, wastewater treatment, and even making drinking water. Scientists are exploring ways to enhance these membranes so they can produce more water without compromising their filtering ability and also reduce pollution. To this end, many scholars are committed to developing new membrane materials and modifying membranes to improve their application effects. There are many methods to modify membrane materials, such as copolymerization, mixing and surface modification. Blending is simple and easy, making it a popular topic in membrane research. That's why many scientists in the field pay attention to it.   Polyvinyl alcohol (PVA 088-08 & PVA 1088)  has good film-forming properties and pollution resistance, and is widely used as a material for preparing hydrophilic membranes.PVA membranes have a tendency to swell and can even dissolve, so they often need some changes, like heat treatment or blending.    To make these membranes, we used materials like polyvinyl alcohol (PVA), cellulose acetate (CA), glacial acetic acid, metal chlorides, and water. We created blended ultrafiltration membranes using a method called phase inversion, adding metal chlorides like sodium chloride (NaCl), potassium chloride (KCl), and barium chloride (BaCl). We checked how the amount of these metal chlorides impacted the performance of the blended membranes.   Our results showed that when the mass fraction of NaCl and KCl doesn't go over 1% in the membrane solution, the modified blended membrane performs well in retaining substances. The pure water flow increases, while energy use stays pretty much the same. But, when the mass fraction goes above 1.5%, the water flow jumps significantly, but the retention rate drops. We found that about 1% is the best amount for the alkali metal chlorides, while for BaCl, around 1.5% works best. Under the same conditions, blending with KCl results in the highest water flow rate. After we changed the PVA-CA blended membrane with NaCl and KCl, it became more water-loving. But when we used BaCl, it got a bit less water-loving.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com  

Polyvinyl Alcohol (PVA) adhesive is a versatile and widely used product in industries. Its unique properties make it an excellent choice for applications such as paints and coatings, paper making, textiles, and more.   PVA (PVA 088-07 & PVA 0888) adhesive has gained popularity in the paints and coatings industry due to its exceptional bonding properties. It provides strong adhesion to various surfaces, including wood, metal, and plastics, making it ideal for both interior and exterior applications. PVA adhesive offers excellent water resistance, flexibility, and durability, ensuring long-lasting results. Its ease of use and low odor make it a preferred choice for professional painters and DIY enthusiasts alike.   The paper making industry relies heavily on PVA adhesive for its superior binding capabilities. PVA adhesive enables the production of high-quality paper products by providing excellent adhesion between fibers. It improves paper strength, enhances printability, and reduces paper breakage during processing. Additionally, PVA offers good water solubility, which is essential for the controlled dissolution of paper in recycling processes.   In the textile industry, PVA adhesive plays a vital role in various applications, such as fabric finishing, laminating, and bonding. PVA adhesive provides a strong bond between different types of fabrics, ensuring secure seams and preventing fraying. It enhances the fabric's overall stability and durability, making it suitable for applications requiring resistance to washing, dry cleaning, and repetitive mechanical stress.   As a water-soluble polymer, PVA offers numerous advantages over other types of adhesives. Its water solubility allows for easy cleanup, reducing the need for harsh chemicals during application and removal. PVA adhesive can be easily diluted to achieve desired viscosity, making it suitable for a wide range of applications. Its non-toxic nature and low environmental impact further contribute to its appeal as a sustainable adhesive option. Polyvinyl Alcohol adhesive stands out as a reliable and versatile choice across various industries. Its exceptional bonding properties, water resistance, flexibility, and ease of use make it a preferred adhesive for paints and coatings, paper making, textiles, and more. Whether it's enhancing the quality of paper products, improving the durability of textiles, or providing a reliable bond in various applications, It continues to be an indispensable tool for industry professionals. Consider incorporating PVA adhesive into your manufacturing processes to benefit from its numerous advantages.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol(PVA) and Vinyl Acetate–ethylene Copolymer Emulsion(VAE) with strong recognition and excellent plant facilities of international standards.

PVA film, also known as polyvinyl alcohol film, is a remarkable polymer-based packaging material that offers a multitude of advantages for various industries.PVA film is non-toxic and safe for direct contact with food and pharmaceutical products. It meets regulatory standards for food contact materials and does not compromise the quality or safety of the packaged items. PVA film is also used in specialized industrial applications, such as the packaging of adhesives, dyes, and chemicals, thanks to its excellent moisture resistance and barrier properties.   One of the notable variants of PVA film is the PVA water-soluble film. This film is specially designed to dissolve quickly and completely in water, making it an ideal choice for single-use packaging applications. The PVA water-soluble film provides exceptional convenience and eco-friendliness, especially in industries such as food packaging, detergent packaging, and agricultural applications.   In contrast to the water-soluble grade, PVA insoluble film offers excellent resistance to moisture and provides a robust barrier to protect the packaged contents. This type of film is commonly utilized in applications where moisture resistance is critical, such as electronic components packaging, chemical packaging, and industrial materials packaging.   PVA special film refers to the customized versions of PVA film that are tailored to meet specific requirements of different industries. These films may possess additional functionalities, such as enhanced strength, increased clarity, improved tear resistance, or specific barrier properties. PVA special films find applications in diverse sectors like pharmaceutical packaging, cosmetic packaging, and Marble demoulding industrial applications.   PVA (PVA 098-08 & PVA 1099) film can be manufactured in different thicknesses and sizes to suit various packaging needs. Its compatibility with different substances allows it to be used with a wide range of products, including powders, liquids, and solid items. ElephChem can customize PVA film of various sizes and specifications according to customer requirements, suitable for a variety of products.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com