A kind of preparation method of high bulk density polyvinyl butyral resin

Abstract

The invention discloses a preparation method of polyvinyl butyral resin with high bulk density. The preparation method is characterized by comprising the following steps of mixing water, polyvinyl alcohol and n-butanal, and stirring by an emulsifying machine, so as to prepare a polyvinyl alcohol / n-butanal water emulsion; simultaneously and continuously adding the polyvinyl alcohol / n-butanal water emulsion and an inorganic acid water solution into a high-shear mixer, mixing and reacting, and continuously conveying the reacted material from the high-shear mixer to an aging kettle; dripping the n-butanal, sequentially reacting for 1-2h at the temperature of 29-31 DEG C in the first section, for 2-3h at the temperature of 59-61 DEG C in the second section, and for 2-3h at the temperature of 69-71 DEG C in the third section, and completing the polymerizing process; filtering, washing and drying, so as to obtain the polyvinyl butyral resin. The preparation method has the advantages that the polyvinyl butyral resin product with bulk density of 30-35g / 100ml and good property is prepared; the cost is reduced, the processing property of the product is improved, and the practicality is strong.

Description

Technical field [0001] The invention belongs to the preparation of polymer compounds, and relates to a method for preparing high bulk density polyvinyl butyral resin. The high bulk density polyvinyl butyral resin prepared by the invention is suitable for automotive safety glass, architectural safety glass, photovoltaic packaging materials and other fields. Background technique [0002] Polyvinyl butyral (abbreviated as PVB) is obtained by acetalization of polyvinyl alcohol (abbreviated as PVA) and n-butyraldehyde under the catalysis of inorganic acid. PVB resin has good light transmittance, cold resistance, impact resistance, film-forming properties, etc. PVB film prepared from PVB resin, plasticizers and additives has very excellent light transmittance, cold resistance, and It is widely used in automotive safety glass, architectural safety glass, photovoltaic packaging materials and other fields due to its characteristics of oxidation, toughness, and adhesion. [0003] The tradi...

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Problems solved by technology

In the subsequent heterogeneous reaction system, since the n-butyraldehyde droplets and unreacted PVA molecules are wrapped by PVB particles, the diffusion rate of the reaction materials is seriously affected, and crosslinking and agglomeration are prone to occur, resulting in uneven product particles, Bulk density is low (usually only 18 ~ 25g / 100ml)

The low bulk density not only brings difficulties to the subsequent washing and drying processes, but also seriously affects the optical properties, equipment investment costs, packaging and transportation costs and performance of PVB products.

[0005] As an improved method, n-butyraldehyde is added or dropped into the reaction system in batches, although it is beneficial to the dispersion of n-butyraldehyde in the reaction system, but the local concentration of n-butyraldehyde is still high at the moment of adding, and the operation cumbersome

The method of fully mixing n-butyraldehyde and PVA solution in advance to form an emulsion, and then mixing and reacting with a catalyst can effectively disperse n-butyraldehyde, but because n-butyraldehyde has been added at one time, the acetalization reaction The rate and extent of the process are uncontrollable, limited by temperature and equipment conditions, the PVB particles produced are often thicker and have a lower bulk density

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