POWDER COMPRISING BLOWING AGENT AND PROCESS FOR PRODUCING THE SAME

摘要

1. A powder comprises a blowing agent. powder core, which is coated with at least one oil-like substance on its surface. 2. The powder according to claim 1, wherein the oil-like substance is used in an amount of 0,001 to 10 parts by weight based on 100 parts by weight of the blowing agent powder. 3. The powder according to claim 1, wherein the oil-like substance is used in an amount of 0,1 to 0,5 parts by weight based on 100 parts by weight of the blowing agent powder. 4. The powder according to claim 1, wherein the oil-like substance is at least one selected from the group consisting of oils and fats in a liquid to solid state, hydrocarbons, and fatty acids. 5. The powder according to claim 1, wherein the oil-like substance is liquid paraffin. 6. The powder according to claim 1, wherein the blowing agent powder cores are azodicarbonamide. 7. The powder according to claim 1, wherein the humidity does not exceed 0,03% by weight. 8. The powder according to claim 1, additionally treated with surface-treating agent capable of removing water from the blowing agent. 9. The powder according to claim 8, wherein the surface-treating agent is at least one selected from the group consisting of a coupling agent, an organic acid anhydride, an anhydrous inorganic compound, and a desiccant. 10. The powder according to claim 8, wherein the surface-treating agent is at least one selected from the group consisting of a silane coupling agent, an aluminium-coupling agent, and a titanate-coupling agent. 11. A. process for producing a powder comprising a blowing agent powder core which is coated with at least one oil-like substance on its surface, comprising the following steps (a) and (b): (a) adding at least one oil-like substance in the form of a mist to a blowing agent powder; and (b) mixing the oil-like substance with the blowing agent powder under such mixing conditions that the blowing agent powder is less susceptible to pulverisation. 12. The process according to claim 11, wherein the oil-like substance with the blowing agent powder is mixed under such mixing conditions that an increase of the specific surface area through the mixing is 20% or less. 13. The process according to claim 11, wherein the oil-like substance with the blowing agent powder is mixed under such mixing conditions that an increase of the specific surface area through the mixing is 10% or less. 14. The process according to claim 11, wherein the oil-like substance is used in an amount of 0,001 to 10 parts by weight based on 100 parts by weight of the blowing agent powder. 15. The process according to claim 11, wherein the oil-like substance is used in an amount of 0,1 to 0,5 parts by weight based on 100 parts by weight of the blowing agent powder. 16. The process according to claim 11, wherein the oil-like substance is at least one selected from the group consisting of oils and fats in a liquid to solid state, hydrocarbons, and fatty acids. 17. The process according to claim 11, wherein the oil-like substance is liquid paraffin. 18. The process according to claim 11, wherein the blowing agent powder is axodicarbonamide. 19. The process according to claim 11, which further comprises the following step (c): (c) adding to the blowing agent powder a surface-treating agent capable of removing water from the blowing agent. 20. The process according to claim 19, wherein the surface-treating agent is added in the form of a mist. 21. The process according to claim 19, wherein the step (c) is carried out prior to or during the step (a). 22. The process according to claim 19, wherein the surface-treating agent is at least one selected from the group consisting of a coupling agent, an organic acid anhydride, an anhydrous inorganic compound, and a desiccant. 23. The powder according to claim 19, wherein the surface-treating agent is at least one selected from the group consisting of a silane coupling agent, an aluminium-coupling agent, and a titanate-coupling agent.