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1 PVA (PVA 088-20 & PVA 1788) water resistance modification PVA (Polyvinyl alcohol) has very low air permeability and is a high-barrier packaging material with excellent performance. Because the molecular chain contains a large number of hydroxyl groups and has high hydrophilicity, these hydroxyl groups are easy to form hydrogen bonds with water molecules under high humidity, resulting in changes in the aggregate structure of PVA, causing its barrier properties to drop sharply. Therefore, necessary water resistance modification should be carried out on PVA to reduce the effect of humidity on the barrier properties of PVA. The mechanism of PVA water resistance modification is to cross-link PVA by adding a cross-linking agent, and completely or partially block the hydroxyl groups, which can reduce its hydrophilicity and achieve the purpose of improving water resistance. The 8511 Institute of the China Aerospace Corporation has developed a melamine resin modified liquid "868" that has no toxic side effects on the human body. "868" is a multifunctional polycondensate. When the amount added is not large, it can moderately cross-link with the hydroxyl groups in PVA, so that PVA forms a strong three-dimensional structure coating, which determines the air tightness of PVA under wet conditions and improves water resistance. This modified PVA coating liquid will not form a skin at room temperature, will not swell or fall off when in contact with water, and can be used for glue preparation and coating at room temperature.   2 PVA (PVA 100-27 & PVA 1799)water-soluble modification PVA's water solubility can be used to make water-soluble films. Water-soluble films are a new type of green and environmentally friendly packaging material, which is widely used in the packaging of various products in Europe, America, Japan and other countries. For example, pesticides, fertilizers, pigments, detergents, water treatment agents, concrete additives, detergents, chemical reagents for photography and chemical reagents for gardening care. Because the water solubility of pure PVA film cannot meet the requirement of dissolution time ≤ 300s in water at 20℃, Wen Huojiang et al. carried out Michael addition reaction with PVA and acrylamide, and then hydrolyzed and synthesized modified PVA under base catalysis. Water-soluble anionic groups were introduced into the PVA molecular chain to enhance the solubility. Water-soluble films were prepared using this as raw material, and the relationship between the amount of alkali, acrylamide and modification rate was discussed. The modification rate made a great contribution to the low-temperature rapid solubility of the prepared film within a certain range. The effect on water solubility beyond a certain range was not significant, but it would lead to excessively high costs.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

The US International Trade Commission determined, in accordance with the Tariff Act of 1930, that the revocation of the anti-dumping duty order on certain Polyvinyl Alcohol (PVA) originating in China, Japan and South Korea imported into the United States may cause substantial damage to the US industry. In 2002, Celanese and DuPont launched anti-dumping investigations against the above countries. In 2003, the ITC decided that Japanese imports were a risk for injury, but they left out Germany. They also excluded China's Sichuan Weiye Company because it didn't meet the required standards at the time. On the other hand, they found that Shanghai Volkswagen was indeed dumping. In July and October 2003, the United States officially imposed anti-dumping duties on PVA from China, Japan and South Korea.     ITC clearly defined the "domestic similar products" of polyvinyl alcohol (PVA) in the review. According to the Tariff Act, similar products refer to products that are similar or most similar to the investigated goods in terms of characteristics and uses. The Ministry of Commerce has limited the scope of the investigation to PVA with a degree of hydrolysis exceeding 80%, while excluding 15 specific forms of PVA.   PVA is a water-soluble synthetic polymer in the form of white particles or powders, and its properties are mainly determined by the degree of hydrolysis, viscosity and molecular weight. In terms of production process, PVA is produced by hydrolysis of vinyl acetate monomers under the action of a catalyst after polymerization. In the USA, PVA is captively consumed or sold to end users primarily as an intermediate in the production of PVB, which is a plastic laminate used as an adhesive between panes of automotive safety glass or load-resistant architectural glass.  PVA is also sold to end users (and occasionally to distributors) for use in the textile and paper industries in sizing formulations(such as PVA 098-08 & PVA 1099); as a binder in adhesive and soil binding formulations（such as PVA 088-20 & PVA 1788); and as an emulsion or polymerization aid in colloidal suspensions, water-soluble films, cosmetics, and joint compounds (such as KURARAY POVAL 17-94).    Although different grades of PVA have differences in specific applications, the committee believes that all PVAs with a degree of hydrolysis exceeding 80% should be considered as the same type of product. This decision is based on three main points: first, all types of PVA share the same basic chemical makeup; second, different grades of PVA can be swapped for each other in many cases; and third, the way they are made and the materials used are pretty similar. It's important to note that while end users tend to stick to one specific grade of PVA to keep costs down, this habit doesn't change the fact that the product itself is quite uniform.   In this review, the Commission stuck with the product definition from the original investigation for two reasons: major manufacturers like Celanese and DuPont agreed with it, and the market hasn’t changed much since then. This decision also continues the Commission's position in the original investigation, that is, not to classify PVB-grade PVA into different product categories.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

  1.Glue for paper packaging and cardboard: efficient bonding, environmentally friendly and safe VAE adhesives suitable for cardboard packaging, film-sheet lamination, paper tube/honeycomb sponge molding, as well as envelope making and book binding. This product line has some great technical benefits. It offers strong bonding and good heat resistance for different materials, including engineering plastics like PET and PS. Plus, it cures quickly, which can help boost production efficiency. Its formula system combines diversity and safety. It not only meets the regulatory requirements of food contact materials, but also has excellent spraying suitability, ensuring stable and uniform sizing effects during high-speed production, while keeping the equipment clean and reducing maintenance frequency. Recommended products: VINNAPAS EP 706K, EP 707K; VINNAPAS EAF 67, EAF 68     2. Woodworking glue: high strength, low formaldehyde VAE adhesives are really flexible when it comes to wood processing. They are great for things like furniture, wood floors, plywood, and doors and windows.This adhesive has excellent water resistance and heat resistance, fast curing speed, and adopts innovative DPX technology to achieve a hardener-free formula. At the same time, the formaldehyde content is controlled below 5ppm, effectively solving the yellowing problem. Its excellent overall performance is particularly suitable for impregnated paper or PVC veneer. In addition, VAE adhesives can ensure that the surface of the product reaches a very high degree of flatness, and support the addition of medium to high proportions of PUD (polyurethane dispersion), providing professional and efficient bonding solutions for various wood processing needs. Recommended products: EP 706K, EP 707K, VINNAPAS EP 645     3. Textile laminating adhesive: strong and water-resistant, cost-optimized The application of VAE adhesives in the textile industry covers the efficient lamination of cloth and sponge, artificial leather and PVC veneer, providing a variety of product options, covering a wide range of needs from high viscosity to low viscosity, and can provide high solid content formulas. Its excellent water resistance and excellent wet peel strength ensure a strong and lasting bonding effect.Plus, they require less thickening agent, plasticizer, and solvent, which means you can save on costs. Most importantly, VAE has excellent compatibility with materials such as natural latex, acrylic emulsion, polyurethane emulsion and styrene-butadiene latex, making it more cost-effective in various applications. Recommended products: EP 706K, VINNAPAS EP 708, EP 645     4. Tobacco glue: high-speed production, ultra-low residue VAE emulsions are really useful in the tobacco industry, especially for various types of adhesives like cigarette glues (including overlapping, nozzle, and packaging glues) and special adhesives for fast packaging machines. One of their main benefits is that they have very low levels of formaldehyde (less than 15 ppm) and residual vinyl acetate (under 100 ppm), which meets strict health and safety rules. There’s a full range of formulas available, from low to high viscosity, and they offer options with high solid content to suit different production needs. Recommended products: VINNAPAS EP 710, VINNAPAS 756   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

WACKER makes VINNAPAS VAE dispersions, which are polymer binders made from vinyl acetate-ethylene (VAE) copolymers. These binders help make many products work better and be more eco-friendly. WACKER is the top producer of VAE dispersions and redispersible polymer powders. You can find their products in lots of areas like coatings, tile adhesives, exterior thermal insulation systems, self-leveling screeds, interior plasters, paper coatings, and adhesives. What are VAE Copolymer Dispersions? These copolymers are created by mixing vinyl acetate, a hard monomer, with ethylene, a soft monomer, through emulsion polymerization. The ethylene adds flexibility to the VAE dispersions, so they don’t need extra plasticizers.   Great Rheological Properties VINNAPAS dispersions that use polyvinyl alcohol (PVOH) are easy to work with for many adhesive tasks, like paper and packaging (VINNAPAS 706 & VINNAPAS 710) . They’re good for different application methods too, such as roller and spray coating(VINNAPAS EP 705 A).   Reduced Migration The special makeup of the copolymer means that we don't need plasticizers or film-forming agents in products with VAE dispersions. This opens up many options for making low-migration adhesives.   Improved Workability Dispersions made with surfactants usually have better shear-thinning properties compared to those made with polyvinyl alcohol. This leads to better sticking to plastics, clearer films, more water resistance, and easier spraying, which makes it easier to work with floor adhesives. Plus, they can handle more fillers.   APEO Removal When making dispersions for adhesives, we don't need to use surfactants with APEOs (alkylphenol ethoxylates). So, VINNAPAS dispersions meet tougher environmental standards (such as VINNAPAS EP 7000).   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

Butvar brand resins generally are soluble in alcohols, glycol ethers, and certain mixtures of polar and nonpolar solvents. In general, Butvar B-98 (PVB Resin B-05SY) resin will show the same general compatibility characteristics as Butvar B-90 (PVB Resin B-02HX) and, therefore, should prove advantageous where physical and chemical properties of B-90 are desired but lower solution viscosities are necessary. The same is true for Butvar B-79 in relation to Butvar B-76.     The lower hydroxyl content of Butvar B-76 and Butvar B-79 permits solubility in a wider variety of organic solvents as compared to the other grades of Butvar. One notable exception, however, is the insolubility of Butvar B-76 and Butvar B-79 in methanol. All other types of Butvar contain sufficient hydroxyl groups to allow for solubility in alcohol and in hydroxyl-containing solvents. The presence of both butyral and hydroxyl groups permits solution in mixtures of alcohol and aromatics. Viscosities of Butvar resin solutions containing mixed solvents depend on the ratio of alcohol to aromatic. Viscosity curves for Butvar B-76, Butvar B-90, and Butvar B-98 in Graph 2 show minimum points in the general vicinity of 50% alcohol: 50% aromatic.     A common solvent for all of the Butvar resins is a combination of 60 parts toluene and 40 parts ethanol (95%) by weight. For compositions of Butvar, methyl alcohol will tend to give the lowest viscosity and, therefore, will permit the use of higher solids when used as a component of a solvent blend. When much more than 10% to 15% alcohol is used in a formulation for spray application, blushing may result. They are useful as starting points in the development of solvent blends for the other types.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

The different kinds of Butvar resins have their properties laid out in Tables 1 to 5. These resins come in various molecular weights and viscosities. Butvar 76 and Butvar 79 resins have less hydroxyl content compared to other Butvar options, which gives them better solubility.   Generally, when you swap butyral groups for acetate groups, you get a polymer that repels water better and can handle heat more without deforming. This change also boosts the polymer's strength and how well it sticks to different surfaces. The strong sticking power of polyvinyl butyral resins comes from their terpolymer structure. Since each molecule has a choice of three different functional groups on its surface, the likelihood of adhesion to a wide range of substrates is significantly increased.   Although polyvinyl butyral resins (PVB) are generally thermoplastic and soluble in a number of solvents, they can be crosslinked by heat and small amounts of mineral acid.Crosslinking often happens through transacetalization, but it can also be due to more complicated processes, like reactions between acetate or hydroxyl groups on nearby chains.   In practice, crosslinking of polyvinyl butyrals is achieved by reaction with various thermosetting resins such as phenolic, epoxy, urea, dicyanate, and melamine resins. The availability of functional hydroxyl groups in Butvar resins for this type of condensation is an important factor in many applications. Including even a small amount of Butvar resin in thermosetting compositions will significantly improve the strength, flexibility, and adhesion of the cured coating.     Polyvinyl butyral films are known for their great resistance to various substances like aliphatic hydrocarbons and different kinds of oils, except for castor and gypsum oils. They tolerate strong bases, but are sensitive to strong acids. However, when used as components of cured coatings, their resistance to acids, solvents and other chemicals is greatly increased. Butyral withstands temperatures up to 200°F for long periods with little color change.   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  

The scientific name of PVB resin is polyvinyl butyral resin. It was successfully industrialized in the United States in the 1930s and has a history of more than 70 years. my country has been trying to industrialize it since the 1960s, but due to the sensitivity of raw materials and process parameters, the product quality fluctuates greatly. The few finished products can only meet military purposes. It was not until the 1990s that a small amount of PVB (B-06HX &PVB B-20HX) products entered the civilian market.   Due to the different processes of PVB manufacturers, the requirements for PVB quality indicators are also different. Not only are there certain restrictions on the viscosity range, but there are also clear requirements for many indicators such as acetalization degree, tensile strength, and film-forming properties. Therefore, it is very easy to make PVB resin. However, it is quite difficult to make products that satisfy users. In order to produce PVB resins that meet user needs and improve the qualified rate of products, the following countermeasures should be taken:   Carefully select raw materials PVA PVA has a variety of models (such as PVA 088-50 & PVA 2488, Mowiol 47-88), not only with different degrees of polymerization, but also with different degrees of alcoholysis. To figure out how much acetalization you need, pick a PVA that meets the viscosity requirements. Try to keep the process conditions the same so that the product quality stays good without putting in extra effort. Process control programming At present, the production of China PVB resin adopts two-step precipitation method, kettle operation, and intermittent production. The production control is mainly manual control, which is quite arbitrary, especially the viscosity of PVB. The viscosity changes greatly with a slight change in the process.It's a good idea to use a DCS control system for making PVB resin. Stick to a programmed operation and keep the process steps pretty much the same for each customer. Strict finished product management It is best to adopt order-based production, and deliver it to customers in time after production is completed. Products that have not been delivered to customers must be placed separately and must not be mixed. For products that have been parked in the warehouse for more than one month, re-sampling and analysis are required before leaving the factory to prevent degradation of PVB resin powder. Disposal of unqualified products Some products may not meet the requirements of a certain user for individual indicators, but there is no problem with the quality of the batch of products itself. The usual practice is to find users with the same or similar quality as the batch of products and make appropriate treatments based on the degree of compliance. If the same products can be sent directly to the user, if the same products are not met, measures such as return package and add can be taken. Products with quality problems can only be sold as waste or destroyed.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com  

Polyvinyl alcohol (PVA) is an important chemical raw material, used to make polyvinyl acetal, gasoline-resistant pipes and vinylon synthetic fibers, fabric treatment agents, emulsifiers, paper coatings, adhesives, glues, etc.     Different grades Polyvinyl alcohol is obtained by hydrolysis of polyvinyl acetate, but not directly by polymerization of vinyl alcohol. Because vinyl alcohol is extremely unstable, it is impossible to have free vinyl alcohol monomers.   Different degree of polymerization There are generally three kinds of alcoholysis degree, namely 78%, 88%, and 98%. Completely hydrolyzed polyvinyl alcohol is obtained by hydrolyzing polyvinyl acetate with a degree of hydrolysis of 98% to 100%. The degree of hydrolysis of partially hydrolyzed polyvinyl alcohol is generally 87% to 89%. To keep things simple, the numbers for polymerization are usually listed first, followed by the percentage of hydrolysis. So, PVA-1788 (Poval 217) means it has a polymerization degree of 1700 and a hydrolysis degree of 88%.   Different water solubility PVA-1788 is well soluble in water and can be quickly dissolved in cold water or in boiling water. The viscosity of PVA-2488 (Mowiol 47-88) is 1.5-2 times that of 1788 (different manufacturers' grades). The dissolution process of 2488 is longer than that of 1788, and its tensile force after dissolution is greater than that of 1788.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com  

With the continuous development of science and technology, PVA (polyvinyl alcohol) is an important polymer compound and is widely used in various fields. In the market, PVA has many different models, and there are certain differences and characteristics between them. Next, we will introduce the differences and application scenarios of various PVA models in detail.   Let's discuss one of the common PVA models-PVA-1788. PVA-1788 has a high degree of polymerization and alcoholysis, and its solubility is good. It can be used to prepare high-transparency hydrogel products. Due to its unique physical properties, PVA-1788 is widely used in the medical and health fields, such as making waveforms to simulate human tissue. PVA-1788 can also be used as a film-forming agent for electrolyte and nutrient sustained-release systems, and is used for soil improvement in the agricultural field.     Another common model is PVA-117. Compared with PVA-1788, PVA-117 has a lower degree of polymerization and a slightly higher degree of alcoholysis. This makes PVA-117 easier to dissolve in water, and has good adhesion and fluidity, making it widely used in the preparation of adhesives. Not only that, PVA-117 can also be used as a stabilizer for the preparation of iron oxide nanoparticles, as well as an emulsifier in coatings, etc.     There is also a special type of PVA, namely PVA-217. PVA-217 is characterized by a low gelation temperature, good thermal stability, and is widely used in the fiber field. In the textile industry, PVA-217 can be used for needle spinning to give the yarn a higher tensile force and lower breaking strength. PVA-217 can also be used as a cross-linking agent for cellulose fibers, playing an important role in the textile processing process.   In summary, PVA, as an important polymer compound, has different types of products to choose from in different application fields. PVA-1788 is suitable for medical and health and agricultural fields, while PVA-117 is widely used in adhesives and coatings, and PVA-217 is mainly used in the textile field.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

  Production process of PVB:   Currently,Polyvinyl Butyral Resin (PVB) is mostly produced using an extrusion casting method. China has made some high-end PVB in the past, especially for the military, like in aircraft and military vehicles, but there hasn’t really been a large-scale market for it.   Since the technology behind PVB is a closely guarded trade secret, we don’t have a clear public description of the process. Still, we can get a rough idea from technical documents: 1. First, the raw materials are fed into different extruders by the feeding system, and the pellets are evenly plasticized and molten in the extruder by heating; 2. The molten body passes through the filter to remove impurities; 3. The melted material flows out through the adjustable discharge port after removing the impurities until it cools down and takes shape as a film. 4. The film passes through the automatic X-ray measurement system to see if the thickness meets the technical requirements; 5. After the film goes through processing, it gets treated on the surface, trimmed, wound automatically, and cut into shape. At this point, it's ready as a final product.   For PVB film, it’s important that the surface is flat. If the film is 0.76mm thick, any thickness variation should be no more than 0.02mm. When measuring in both vertical and horizontal directions over a range of 50mm, the error should be under 0.006mm. Also, the moisture content has to stay below 0.3%, and the natural rating should be under 12%.     The technical difficulty of PVB production：   In terms of process, the ratio of polyvinyl butyral resin and plasticizer is one of the key points to determine the quality. In addition, since PVB has high requirements for humidity, special treatment is required during slitting, packaging, storage, and transportation;PVB needs specific humidity levels, so we have to be careful with slitting, packaging, storing, and transporting it. Plus, to make high-quality PVB, we need good resin, which means new projects will need extra resin production areas. This adds some new challenges for managing the process.   For PVB (such as Butvar B-74) in the solar industry, there are extra demands for resistivity and temperature compared to what’s needed for regular car glass or curtain walls. Usually, the resistance furnace requires more than 1000 ohms/cm2; the temperature must be lower than the tolerance temperature of the film to avoid damaging the reaction layer.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

PVA (polyvinyl alcohol) is a white, powdery resin obtained by hydrolysis of polyvinyl acetate. Since my country began researching and producing it in the 1960s, its current output ranks first in the world. Polyvinyl alcohol film is great because it's really clear, lightweight, and can keep gases out. It's tough, won't tear easily, and can handle wear. Plus, it can dissolve in water and break down naturally under the right conditions. It is one of the new green materials that has developed rapidly in recent years.   At present, the high-barrier packaging materials on the market mainly include polyvinylidene chloride (PVDC), ethylene-vinyl alcohol copolymer (EVOH) and polyvinyl alcohol (PVA). Polyvinylidene chloride (PVDC) is mainly used in the coating process. PVDC has good oxygen and water vapor barrier properties, and the coating can be heat-sealed with low cost. However, PVDC because of the chloride ions in its structure, it cannot be recycled and reused. When the waste is incinerated, it will also produce hydrogen chloride, dioxins and other toxic and harmful substances to the human body and the surrounding environment. Europe and the United States have begun to restrict its use.     Ethylene-vinyl alcohol copolymer (EVOH) has excellent barrier properties and excellent processability. It has excellent transparency, gloss, mechanical strength, elasticity, wear resistance, cold resistance and surface strength. It only produces CO2 and H20 when incinerated, and is an excellent green and environmentally friendly packaging material. However, when the ambient temperature is relatively high, its barrier properties deteriorate sharply, so it is not suitable for use alone. It is mostly used in the production of multi-layer co-extruded films, such as EVOH five-layer co-extruded films, but most of the equipment relies on imports and is costly.   Polyvinyl alcohol (PVA,PVA 2688 & PVA 088-60) contains a large number of hydroxyl groups in its molecular structure and has hygroscopic energy. As the humidity increases, its gas barrier function decreases. It needs to be coated or plasticized in large quantities before it can be processed and formed. Therefore, the modified PVA coating film that has been hydrophobically modified is often used in the coating process. It has been widely used in the United States and Japan, and has begun to flourish in my country in recent years.   The continuous development and progress of society has prompted people to put forward more requirements and expectations for new materials that are safe, environmentally friendly, degradable and recyclable. The development of the technology of modified PVA coating film that has emerged will not stop. The booming plastic processing industry calls for the birth of new generations of new products. It can be expected that in the near future, as the technology of modified PVA coating film becomes more mature, its share in the structural grade and economic benefits of plastic packaging market products will become larger and larger.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com