PVB Resin B-03HX

Polyvinyl butyral resin (PVB) is a solvent-based resin synthesized by acetalization reaction of polyvinyl alcohol (PVA ) and butyraldehyde under the action of coal catalyst     General characteristics The appearance of PVB is white spherical porous particles or powder, and its specific gravity is 1:1; but the filling density is only 0.20~0.35g/ml. Thermal properties The glass transition temperature (Tg) of PVB ranges from 50℃ for low overlap to 90℃ for high overlap; this glass transition temperature can also be adjusted to below 10℃ by adding an appropriate amount of plasticizer. Mechanical properties PVB has excellent film-forming properties and gives the coating film quite good properties such as warp strength, tear strength, abrasion resistance, elasticity, flexibility, gloss, etc.; it is especially used in bonding safety glass interlayers, making the glass have strong impact resistance and penetration resistance, and it is still not replaced by other materials. Chemical properties PVB coatings have good water resistance, resistance and oil resistance (resistance to aliphatic, mineral, animal and plant oils, but not castor oil). Because PVB contains high hydroxyl groups and has good dispersibility for pigments, it is widely used in printing inks and coatings. In addition, its chemical structure contains both hydrophobic acetal and acetate groups and hydrophilic hydroxyl groups, so PVB has good adhesion to glass, metal, plastic, leather and wood. Chemical Reaction Properties Any chemical that can react with secondary alcohols will also react with PVB. In a lot of PVB applications, it's common to mix it with thermosetting resins. This helps to strengthen the hydroxyl groups in PVB, making it more resistant to chemicals, solvents, and water. Depending on the type of thermosetting resin and how much you mix with PVB, you can create coatings with different features like hardness, toughness, and impact resistance. Safety Properties Pure PVB is non-toxic and harmless to the human body. In addition, ethyl acetate or alcohol can be used as solvents, so PVB is widely used in printing inks for food containers and plastic packaging in Europe and the United States. Storability Properties As long as PVB is not in direct contact with water, it can be stored for two years without affecting its quality; PVB needs to be stored in a dry and cool place and avoid direct sunlight. Avoid heavy pressure when storing PVB. Solubility Properties PVB dissolves in alcohol, ketones, esters, and some other solvents. The solubility in various solvents varies according to the functional group composition of PVB itself. Please refer to CCP PVB Solvent Solubility Table. Basically, alcohol solvents mix well, but methanol doesn’t blend as easily with substances that have a lot of acetal groups. The more acetal groups there are, the easier it is to mix with ketone and ester solvents. PVB has good solubility in alcohol ether solvents, like Cellosolve. It only partly mixes with aromatic solvents such as xylene and toluene, and it won’t mix at all with hydrocarbon solvents.   PVB (such as PVB SD-2) has good film-forming properties. The coating formed by PVB has excellent properties such as high transparency, elasticity, toughness, strength resistance, oil resistance, flexibility and low-temperature impact resistance.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com  

Yellowing of the Polyvinyl butyral resin (PVB) at the edges of laminated glass is a rare but important quality issue. You usually see it as two yellow spots about 5 cm wide along the edges. Since this tends to happen often, many customers have complained, leading to some losses for the company. This study investigates the cause by checking the production steps, running tests, and using a microscope to pinpoint the issue and find a solution.     Cause AnalysisMaking laminated glass involves several steps: cutting, edging, lamination, autoclave treatment, and finally packaging, storing, and transporting. We've noticed that the yellowing mainly occurs where the glass vials touch the rack base, specifically in a 5 cm area. This yellowing doesn't appear right after autoclaving; it tends to show up during packaging and storage. Here are a few initial ideas about what might be causing it: Local PVB Aging Due to High Temperature: We tried using glass on a new rack that had a trimmed rubber base and deeper grooves, and there was no yellowing after a day. So, that's not the problem. Plastic Film Aging Contaminating PVB: We tried switching the film with adhesive tape, but there was still yellowing, which means the film isn’t the main culprit. Migration of Yellowing from Rubber Material: Seeing that putting glass on a clean rack stopped it from turning yellow makes it pretty clear that the old rubber parts are the cause of the discoloration.   Testing and Mechanism StudyWe used FTIR and GC-MS to check out the yellowed PVB(Resin B-05SY & PVB SD-2)and rubber materials. The findings included: There weren't any major differences in the composition of PVB or rubber. C-MS detected extra organic compounds in the yellowed PVB, which are rubber additives. These substances migrated to the PVB due to a blooming effect from the EPDM rubber, causing the yellow spots. Optimization SolutionsBased on our findings, we suggest three solutions: Prevent Blooming Migration: Add an inorganic barrier between the glass and rubber. Maintain Rubber Base: Trim aged surfaces periodically. Conclusion Identifying the issue has been really beneficial. This approach could also help address yellowing problems in other materials, like Ethylene Vinyl Acetate (EVA), which might spark some useful ideas for related issues.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com