Composite powder, preparation and use thereof
The present invention relates to a composite powder, preparation and use thereof. The composite powder according to the present invention is prepared by intimately mixing an irradiated or non-irradiated rubber latex with a slurry of inorganic particles in a ratio corresponding to that of rubber particles to inorganic particles in the composite powder according to the present invention, and then drying the resultant mixture. The composite powder according to the present invention comprises agglomerates composed of powdery rubber particles and inorganic particles, with inorganic particles being uniformly distributed either inside the agglomerats or both inside the agglomerates and on the surfaces thereof. The composite powder according to the present invention can be easily dispersed in plastic matrixes and thus can be compounded with plastics to produce toughened plastics and thermoplastic elastomers.
1. A composite powder, comprising rubber particles having a cross-linked structure and a gel content of 60 percent by weight or more and inorganic particles distributed between said rubber particles, wherein the rubber particles have a homogeneous structure and an average particle size of 20 to 2000 nm.
2. The composite powder according to claim 1 , wherein said inorganic particles have an average size of 0.2 to 500 nm in at least one dimension and are selected from elemental metals or alloys thereof; metal oxides; metal or non-metal nitrides; non-metal carbides; non-metal oxides; metal hydroxides; metal salts; mineral earths; and the mixtures of two or more of them; and the weight ratio of the rubber particles to the inorganic particles is from 99.5:0.5 to 20:80.
3. The composite powder according to claim 2 , wherein the weight ratio of the rubber particles to the inorganic particles is from 99:1 to 50:50.
4. The composite powder according to claim 2 , wherein said inorganic particles have an average size of 0.5 to 100 nm in at least one dimension.
5. The composite powder according to claim 1 , wherein said inorganic particles are selected from gold, silver, cupper, iron, gold alloys, silver alloys, cupper alloys, iron alloys, aluminum oxide, magnesium oxide, titanium dioxide, iron sesquioxide, ferroferric oxide, silver oxide, zinc oxide, aluminum nitride, silicon nitride, silicon carbide, silicon dioxide, aluminum hydroxide, magnesium hydroxide, calcium carbonate, barium sulfate, calcium sulfate, silver chloride, asbestos, talc, kaolin, mica, feldspar, wollastonite, montmorillonite, and the mixtures of two or more of them.
6. The composite powder according to claim 1 , comprising agglomerates composed of rubber particles and inorganic particles, with inorganic particles being uniformly distributed either inside the agglomerates or both inside the agglomerates and on the surfaces thereof, wherein the rubber particles themselves have a gel content of 60 percent by weight or more.
7. The composite powder according to claim 1 , wherein said rubber particles have a gel content of 75 percent by weight or more.
8. A composition useful for preparing toughened plastics or thermoplastic elastomers, comprising plastics and the composite powder of claim 1 .
9. The composite powder according to claim 1 , further comprising a water-soluble nucleating agent for plastics in a weight ratio of the rubber particles to the nucleating agent of 99:1 to 50:50.
10. The composite powder according to claim 9 , wherein said nucleating agent is sodium benzoate.
11. The composite powder according to claim 9 , wherein the weight ratio of the rubber particles to the nucleating agent is 97:3 to 70:30.
12. The composite powder according to claim 1 , wherein said composite powder is prepared by a process comprising the steps of vulcanizing a rubber latex by high-energy irradiation in the absence or presence of a cross-linking agent, intimately mixing a slurry of inorganic particles with the irradiated rubber latex to obtain a mixed latex and then spray drying the mixed latex, said rubber latexes are selected from the group consisting of natural rubber latex, styrene-butadiene rubber latex, carboxylated styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, carboxylated acrylonitrile-butadiene rubber latex, polybutadiene rubber latex, neoprene rubber latex, silicone rubber latex, acrylic rubber latex, butadiene-styrene-vinylpyridine rubber latex, isoprene rubber latex, butyl rubber latex, ethylene-proplyene rubber latex, polysulfide rubber latex, acrylate-butadiene rubber latex, urethane rubber latex and fluorine rubber latex.
13. The composite powder according to claim 1 , wherein said rubber particles have an average particle size of 50 to 500 nm.
14. The composition according to claim 8 , wherein the weight ratio of the composite powder to the plastics is 0.5:99.5 to 50:50.
15. The composite powder according to claim 1 wherein the rubber particles contain substantially 100 percent of rubber component.