Fine polymer particles for plastisol, process for producing the same, and halogen-free plastisol composition and article made with the same

Abstract

This invention relates to a fine particle of polymer for a plastisol free from halogen atoms and having a specific surface area of 0.6 to 20.0 m 2 /g as determined by nitrogen-gas adsorption and a non-halogenated plastisol composition therefrom. This invention can provide a non-halogenated plastisol composition which does not generate toxic substances during incineration, is suitable as a coating material or sealant, and has a low viscosity, resulting in good workability and processability.

1. A non-halogenated plastisol composition comprising:
 i) a fine particle of polymer for a plastisol free from halogen atoms and having a specific surface area of 0.6 to 20.0 10 m 2 /g as determined by nitrogen-gas adsorption and an oil absorption rate by linseed oil of 0.8 mL/g or less for linseed oil; and 
 ii) a plasticizer, 
 wherein said fine particle is of at least one polymer selected from the group consisting of acrylic polymers, acrylic copolymers, styrene polymers, styrene copolymers, butadiene polymers, butadiene copolymers, vinyl-acetate polymers, vinyl-acetate copolymers and a mixture thereof, 
 said fine particle contains at least 50 mol % of an alkyl (meth)acrylate unit, 
 the fine particle of polymer has two or more polymer layers having different compositions concentrically from the particle center to its surface, 
 and compatibility of a polymer to a plasticizer in an inner layer close to the center is higher than that in an outer layer close to a particle surface. 
 
     
     
       2. The non-halogenated plastisol composition of  claim 1  wherein the fine particle of polymer has two or more polymer layers having different compositions concentrically from the particle center to its surface. 
     
     
       3. The non-halogenated plastisol composition of  claim 1 , wherein said fine particle of polymer is in the form of agglomerates formed from a plurality of primary particles wherein the primary particles have an average particle size of at least 500 nm. 
     
     
       4. A process for manufacturing a the non-halogenated plastisol composition of claim 1 comprising the steps of:
 preparing an aqueous dispersion of a fine particle of polymer in which primary particles have an average particle size of at least 500 nm; 
 drying the aqueous dispersion at not lower than 50° C. but not higher than a glass-transition temperature of the polymer +20° C., by spray drying; and 
 blending with a plasticizer. 
 
     
     
       5. The non-halogenated plastisol composition of  claim 1 , further comprising an inorganic filler. 
     
     
       6. The non-halogenated plastisol composition as claimed in  claim 5  wherein viscosity values at shear speeds of 10000 sec −1  and 0.42 sec −1  are 0.1 to 1.0 Pa·s (25° C.) and 100 to 1000 Pa·s (25° C.), respectively. 
     
     
       7. The non-halogenated plastisol composition as claimed in  claim 6  wherein the inorganic filler essentially consists of inorganic fillers with an average particle size of less than 2.0 μm (C1) and of 2.0 μm or more (C2) and a component, ratio of these inorganic fillers (C1) to (C2) (by weight) is 30/70 to 70/30. 
     
     
       8. The non-halogenated plastisol composition of  claim 1 , wherein the plasticizer comprises a phthalic acid diester of an aliphatic alcohol having 7 to 10 carbon atoms in at least 50 wt %. 
     
     
       9. An article produced using the plastisol composition as claimed in any of  claims 5  to  8 . 
     
     
       10. The non-halogenated plastisol composition of  claim 1 , wherein said polymer is an acrylic polymer. 
     
     
       11. The non-halogenated plastisol composition of  claim 1 , wherein said polymer is at least one copolymer selected from the group consisting of styrene-butadiene copolymer, acrylonitrile-butadiene copolymers and acryl-vinyl acetate copolymers. 
     
     
       12. A method of coating comprising applying the non-halogenated plastisol composition of  claim 1 ; and curing. 
     
     
       13. A method of sealing comprising applying the non-halogenated plastisol composition of  claim 1 ; and curing. 
     
     
       14. A method of undercoating an automobile comprising applying the non-halogenated plastisol composition of  claim 1  to a surface of an automobile; and curing. 
     
     
       15. The method of coating of  claim 12 , wherein said curing is by heating. 
     
     
       16. The method of sealing of  claim 13 , wherein said curing is by heating.