Polyvinyl Alcohol

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

Polyvinyl alcohol (PVA) is a widely used synthetic material. PVA ability to dissolve in water and break down naturally makes it a good choice for packaging films. The main production methods for PVA film are aqueous solution coating and melt blow molding. PVA is hard to shape with heat because it melts at a higher temperature than it decomposes. This is due to the strong links between its molecules and its crystal structure. Therefore, the most important factor in the processing of PVA film is the selection of appropriate additives.   1. Effect of Plasticizer Amount on Tensile Strength, Tear Strength, and Elongation at Break of Polyvinyl Alcohol Film As shown in Figure 1, film ability to resist breaking lessens as more plasticizer is added. This suggests that plasticizers reduce how strong the film is. The plasticizer gel theory explains that when the plasticizer mixes with the resin, it loosens the points where the resin molecules connect. These connections have different strengths. The plasticizer pulls them apart and hides the forces that hold the polymer together. This reduces the secondary forces between the polymer macromolecules, increases the flexibility of the macromolecular chains, and accelerates the relaxation process. Tensile strength goes down as you add more plasticizer. As the amount of plasticizer is increased, the film becomes more flexible and stretches further before breaking. This suggests that plasticizers make the film more pliable. Plasticizers achieve this by weakening the attraction between the large molecules in the polymer. This increased flexibility and longer relaxation period lead to the film ability to stretch further. The data indicates that as more plasticizer is added, the film becomes easier to tear. This likely happens as the plasticizer reduces the film's surface energy and lessens the energy needed for both plastic flow and lasting deformation. These factors, in turn, contribute to the film's reduced resistance to tearing.   2. Effect of Crosslinker Amount on the Tensile Strength, Elongation at Break, and Tear Strength of PVA Film As shown in Figure 3, the film's tensile strength goes up gradually as the amount of crosslinker is increased, during which the elongation at break goes down gradually. When a certain point is reached, the film's tensile strength goes down gradually, while the elongation at break goes up gradually. At first, as more crosslinker is added, the number of working polymer chains goes up, intermolecular forces get stronger, and the polymer chains become less flexible. The ability of the large molecular chains to change shape and rearrange decreases while the chain relaxation is difficult. So, the tensile strength goes up, while the elongation at break goes down. Continuing the use of crosslinkers causes degradation and branching to increase gradually, which decreases the number of working polymer chains, and increases the flexibility of the polymer chains. The ability of the large molecular chains to change shape and rearrange increases, while the chain relaxation becomes easier. As a result, the tensile strength starts to go down again, while the elongation at break goes back up. As shown in Figure 4, the tear strength of the film changes with the amount of crosslinker. At first, it goes up, but then it starts to go down. This happens because when crosslinking starts, more crosslinker helps the polymer network form. This makes the film's surface energy go up gradually. It then needs more energy to spread plastic flow and irreversible viscoelastic processes. Because of this, the film's tear strength gets better as crosslinking happens. But, if there is too much crosslinker with too much polymer broken down, and there are more branching reactions, the tear strength gets worse.   3. Conclusions When you add more plasticizer, PVA film becomes less strong but stretches and tears more easily. When you add more crosslinker, film strength and resistance to tearing improve at first, but then weaken, while its ability to stretch keeps getting better.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

Redispersible emulsion powder is a modified emulsion powder obtained by spray drying of a binary or ternary copolymer of vinyl acetate and tertiary vinyl carbonate -VeoVa or ethylene or acrylic ester, which has good redispersibility and is re-dispersed into emulsion when it is in contact with water, and its chemical properties are exactly the same as the initial emulsion. After mixing with the water in the mortar, it emulsifies and disperses in the water to form a stable polymerization emulsion. After dispersing in water, the water evaporates, forming a polymer film in the mortar after drying, improving the performance of the mortar. Different dispersible latex powders have different effects on the dry mortar. 1. Improve the impact resistance, durability and wear resistance of mortar The rubber powder particles fill the cavity of the mortar, the densification of the mortar is increased, and the wear resistance is improved. Under the action of external forces will produce relaxation and not be destroyed. The polymer film can exist in the mortar system for a long time.   2. Improve the bonding strength and cohesion of mortar As an organic binder, dispersible emulsion powders provide high tensile strength and bonding strength on different substrates. It plays a very important role in the adhesion between mortar and organic materials (molded plates, extruded plates) and smooth surface substrates. The film-forming polymer rubber powder is distributed in the whole mortar system as a reinforcing material to increase the cohesion of the mortar.   3. Improve the mortar's weatherability, freeze-thaw resistance and prevent mortar crackingThe RDP emulsion powder is a thermoplastic resin adhesive powder with good flexibility, which can make the mortar cope with the external cold and hot environment changes and effectively prevent the mortar from cracking due to the change in temperature difference.   4. Improve the hydrophobicity of mortar and reduce water absorptionThe RDP emulsion powder forms a film in the mortar cavity and surface, and the polymer resin film will not disperse twice after encountering water, preventing the invasion of water and improving the impermeability. Enhanced dispersible adhesive powder with hydrophobic effect has better hydrophobic effect.   5. Improve the bending strength and flexural strength of mortar The polymer film formed by dispersible emulsion powder has good flexibility. The film is formed in the gap and surface of cement mortar particles to form a flexible connection, so that the brittle cement mortar becomes elastic. The mortar added with dispersible emulsion powder has much better tensile and flexural properties than ordinary mortar.   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.

  Polyvinyl alcohol (PVA) has several applications in agriculture, including:   1. Seed coating: PVA can be used as a seed coating material to enhance germination, improve seedling growth, and provide protection against pests and diseases.   2. Soil stabilizer: PVA can be added to soil to improve its structure and stability, especially in erosion-prone areas. It helps reduce soil erosion, increase water retention, and enhance soil fertility.   3. Mulching film: PVA films can be used as mulching materials to cover the soil around plants. This helps to conserve moisture, control weed growth, and maintain stable soil temperatures, leading to improved plant growth and higher crop yields.   4. Slow-release fertilizers: PVA can be incorporated into fertilizer formulations to create slow-release or controlled-release fertilizers. This allows nutrients to be released gradually over time, providing sustained nutrition to plants and minimizing nutrient leaching.   5. Crop protection: PVA can be used as a component in biodegradable agricultural films for crop protection purposes. These films can be used for insect barriers, weed control, and microbial resistance, reducing the reliance on conventional plastic films.   6. Hydrogel applications: PVA hydrogels have been utilized in agriculture for various purposes, such as water retention in drought-prone areas, as carriers for controlled release of agrochemicals, and as bio-based materials for seed germination and plant growth.   These applications demonstrate the versatility of PVA（PVA 088-35 & PVA 2088） in agriculture, providing solutions for improving plant growth, conserving resources, and promoting sustainable farming practices.   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.  

Polyvinyl alcohol (PVA) has various applications in the film industry. Here are some of the common applications of PVA in films:   1. Water-soluble film: PVA can be used to produce water-soluble films that are used for packaging various products such as detergents, agrochemicals, and personal care products. These films dissolve in water, providing convenience and reducing waste.   2. Food packaging film: PVA can be used as a coating or component in food packaging films. It provides excellent oxygen barrier properties, moisture resistance, and aroma retention, helping to extend the shelf life of food products.   3. Biodegradable film: PVA can be used to produce biodegradable films that are environmentally friendly. These films can replace traditional plastic films in applications such as mulch films, agricultural films, and compostable packaging materials.   4. Drug delivery films: PVA films can be used as drug delivery systems in the pharmaceutical industry. These films can be loaded with active pharmaceutical ingredients and used for transdermal patches, oral dissolvable films, or other drug delivery applications.   5. Optical film: PVA can be used in the production of optical films for applications such as LCD displays and optical lenses. These films provide excellent optical clarity, high transparency, and low birefringence.   6. Photographic film: PVA has been widely used in the production of photographic films. It acts as a binder and protective coating, ensuring adhesion of the photo emulsion to the film base and providing surface protection.   Overall, PVA has versatile properties that make it suitable for a wide range of film applications, including water-soluble films, food packaging films, biodegradable films, drug delivery films, optical films, and photographic films.   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 088-50 & PVA 24-88 Polyvinyl alcohol PVA 088-20 & PVA 17-88 Polyvinyl alcohol PVA 100-27 & PVA 1799 Polyvinyl alcohol    

Polyvinyl alcohol (PVA) is used in textile sizing, which is the process of applying a protective coating to yarn or fabric to enhance its weaving and handling properties. In textile sizing, various grades of PVA can be utilized, depending on the specific requirements of the sizing process and the desired characteristics of the finished textile product.   The selection of the PVA grade depends on factors such as the desired viscosity, film-forming properties, adhesion strength, and water solubility. Generally, medium-to-high molecular weight PVA grades with moderate viscosity are preferred for textile sizing applications. These grades offer good film-forming ability, excellent adhesion to the fibers, and compatibility with other sizing agents.   PVA-based sizing formulations may also include additional additives like lubricants, softeners, antistatic agents, and crosslinking agents to further enhance the performance and processability of the sized yarn or fabric.   It's worth noting that the specific PVA ( PVA 100-27 & PVA 1799) grade and formulation used for textile sizing can vary depending on the type of textile fibers being sized (e.g., natural or synthetic fibers), weaving techniques, and the desired properties of the final textile product.   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.

Pharmaceutical grade polyvinyl alcohol (PVA) is a high-purity form of PVA that meets specific quality standards and regulations for use in the pharmaceutical industry. It is used in various pharmaceutical applications, including as a binder, film former, coating agent, and viscosity modifier.   Pharmaceutical grade PVA(PVA 100-27 & PVA 1799) undergoes stringent quality control processes to ensure its purity, stability, and safety. It is typically produced using high-quality raw materials and advanced manufacturing techniques to meet the strict requirements of the pharmaceutical industry.   The properties of pharmaceutical grade PVA, such as its solubility, viscosity, and film-forming characteristics, can be tailored to suit specific pharmaceutical formulations. It is often used in the production of tablets, capsules, oral suspensions, ophthalmic solutions, and topical formulations.   Due to its biocompatibility, low toxicity, and good film-forming properties, pharmaceutical grade PVA is widely accepted and used in the pharmaceutical industry. It plays a crucial role in improving the stability, bioavailability, and overall performance of pharmaceutical products.   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.  

Using succinic acid as the cross-linking agent, through the reaction of COOH- and OH-, an ester group is generated, which cross-links the PVA molecules and generates a modified PVA glue that is insoluble in water. The introduced COOH-group can improve its water resistance, hardness, adhesion, etc.   Weigh an appropriate amount of PVA(PVA 098-08 & PVA 1099), add water, heat it in a water bath with electric stirring, and control the water bath temperature to 80-90°C. After it is completely dissolved, stop heating to obtain PVA glue. In a water bath at a certain temperature, add an appropriate amount of succinic acid to the above-mentioned PVA glue, stir it under closed conditions to react, and cool to room temperature to obtain a modified PVA glue.   Using succinic acid as the cross-linking agent, PVA glue was modified, and the optimal modification conditions were determined to be: PVA glue mass concentration 7%, reaction temperature 85°C, and PVA glue to succinic acid mass ratio 5.6:1. Here Under the conditions, the hardness, adhesion, viscosity and impact resistance of the modified PVA glue obtained were significantly improved, and the water resistance was also improved. This method can be used to prepare PVA adhesives and coatings that require high adhesion and water resistance. 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.  

Polyvinyl acetal mixed aldehyde adhesive can be prepared by using polyvinyl alcohol (PVA) and crotonaldehyde as the main raw materials, hydrochloric acid (HCl) as the catalyst and acetaldehyde as the modifier.   Put a certain amount of PVA into a three-necked flask equipped with a mechanical stirrer and a reflux condensation device, add deionized water, adjust the water bath temperature to 95°C, and keep it warm for 2 hours to fully dissolve it; when the solution cools to room temperature, Slowly add measured HCl dropwise while stirring, and mix thoroughly; heat the water bath to the specified temperature, add crotonaldehyde and acetaldehyde solutions according to the formula, and stir thoroughly; after the reaction is completed, use NaOH solution to adjust the pH value to 8 to 9, and then add Add appropriate amount of urea and stir for 20 minutes.   The results show that when the reaction temperature is (90±2)℃, the reaction time is 4 h, 8% PVA solution is 200 mL, HCl is 1mL, crotonaldehyde is 1.0~1.5mL, and acetaldehyde is 4mL, acetalization The viscosity of the product is moderate, the bonding strength is relatively maximum (4.5MPa), and the water resistance is relatively good; under the premise that other conditions remain unchanged, by changing the amount of crotonaldehyde, the final viscosity of the system can be further adjusted to meet the requirements of wood. Adhesive usage requirements.   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 2488 & 088-50 Modified PVA 725 PVA 1788 & 088-20    

By adding nanoscale reinforcements to the composite matrix, the mechanical properties of the composite (such as strength, stiffness, elastic modulus, etc.) can be significantly improved. The polyvinyl alcohol adhesive modified with nano-silica particles is non-toxic and pollution-free. It will be widely used and is worthy of systematic research.   Current research on the modification of nanoparticles mainly focuses on the following two aspects: one is to use silica as the base, modify its surface with a modifier, and then graft the polymer; the other is to use the polymer as the base, and then graft it. branch modifier, and then graft silica. To modify nanosilica, it is generally dispersed in an organic solvent and then a modifier is added.   Introducing inorganic nanoparticles into the adhesive for modification can improve its tensile bonding strength and elongation at break. When the dosage of nanoparticles is within a certain range, the nanoparticles can be well dispersed into the adhesive matrix. Because of their huge specific surface area, they can interact strongly with the adhesive matrix, thus improving the mechanical properties of the adhesive. However, if the dosage exceeds a certain range, serious agglomeration will occur, the particle interface area will be reduced, the interaction between the nanoparticles and the adhesive matrix will also be weakened, and the content of reactive nanoparticles will be reduced, resulting in a reduction in its mechanical properties. . The mechanical property test results of the nano-modified adhesive show that when the dosage of nano-silica particles is 4%, the various performance indicators of the modified adhesive reach the maximum value.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol(PVA,PVA 098-08 & PVA 1099) and Vinyl Acetate–ethylene Copolymer Emulsion(VAE) with strong recognition and excellent plant facilities of international standards.

The water resistance of polyvinyl alcohol was improved by cross-linking with maleic acid (commonly known as maleic acid, MA). The esterification crosslinking of PVA membrane is achieved through the esterification reaction between PVA molecule and MA at high temperature. The esterification crosslinking reaction actually introduces carbonyl group into the polymer chain of PVA, forming a new polymer, but the main chain of the whole PVA polymer remains unchanged.   The PVA after esterification with MA only has chemical crosslinking, and does not produce a stable crystal structure, so the PVA film is easy to be swollen by water and destroy the structure of the film. Therefore, the PVA film should be heat treated. Since the esterification reaction in the liquid phase is characterized by reversibility, the crosslinking of polymers in the PVA film during the heating process makes the esterification reaction irreversible due to the partial water that has not been removed in the casting liquid and the complete volatilization of the water generated by the esterification reaction of PVA and MA, and the cross-linked PVA film is stable.   PVA (PVA 098-08 & PVA 1099) can improve the water resistance and poor mechanical properties of PVA by chemical crosslinking with MA. Proper concentration of crosslinker and heat treatment conditions can make PVA obtain better water resistance.   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.  

Polyvinyl alcohol (PVA) contains a large number of hydrophilic hydroxyl groups, which exhibit strong affinity for water during external drying and wetting changes. The use of epoxy resin, with high bonding strength and good stability, as a modifier for PVA is mainly because the epoxy groups in the epoxy resin can react with the hydroxyl groups in PVA to form ethers. To carry out the epoxy resin modification method of PVA, measure the required amounts of PVA and water and add them separately to three-necked flasks equipped with stirring and reflux devices. Start stirring and raise the temperature to 90°C, maintaining the reaction for 1 hour to obtain a PVA aqueous solution of a certain concentration. Cool it to 70°C, increase the stirring speed, and add a specific amount of epoxy resin to the glue solution. Maintain the reaction at this temperature for 2 hours to obtain epoxy resin-modified PVA.   Through orthogonal experiments, it has been determined that the optimal reaction conditions for PVA modification are a PVA concentration of 8%, modification time of 2 hours, epoxy resin addition of 2.4% (mass fraction), and modification temperature of 60°C. Under these conditions, the modified PVA exhibits excellent performance in terms of curing degree, which reaches 89.6%, significantly higher than the curing degree of unmodified PVA(PVA 098-08 & PVA 1099), which is 64.5%.   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.