Claims
- 1. A method for preventing the agglomeration of hygroscopic and sublimable powders of piperazine or triethylenediamine, characterized in that a polyvinyl pyrrolidone and/or a vinyl pyrrolidone-vinyl ester copolymer is incorporated as an anti-agglomeration agent to the powder.
- 2. The method according to claim 1, wherein the polyvinyl pyrrolidone is a compound having repeating units of the formula: ##STR3## wherein n is an integer of at least 1, and each of R.sub.1 to R.sub.6 is H or a C.sub.1-4 alkyl group.
- 3. The method according to claim 1, wherein the vinyl pyrrolidone-vinyl ester copolymer has repeating units of the formula: ##STR4## wherein each of n and m is an integer of at least 1, each of R.sub.1 to R.sub.6 is H or a C.sub.1-4 alkyl group, and R.sub.7 is a C.sub.1-2 alkyl group.
- 4. The method according to claim 1, wherein each of the polyvinyl pyrrolidone and the vinyl pyrrolidone-vinyl ester copolymer has an average molecular weight of from 1,000 to 10,000.
- 5. The method according to claim 1, wherein the vinyl pyrrolidone-vinyl ester copolymer is a vinyl pyrrolidone-vinyl acetate copolymer with a polymerization ratio of the vinyl pyrrolidone to the vinyl acetate of from 5/5 to 3/7.
- 6. The method according to claim 1, wherein the polyvinyl pyrrolidone and/or the vinyl pyrrolidone-vinyl ester copolymer is incorporated in an amount of from 0.001 to 2 parts by weight per 100 parts by weight of the powder.
- 7. The method according to claim 1, wherein the polyvinyl pyrrolidone and/or the vinyl pyrrolidone-vinyl ester copolymer is incorporated in an amount of from 0.01 to 0.1 part by weight per 100 parts by weight of the powder.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2-185255 |
Jul 1990 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 07/729,689, filed on Jul. 15, 1991, now abandoned.
US Referenced Citations (17)
Foreign Referenced Citations (3)
Number |
Date |
Country |
2074840 |
Oct 1971 |
FRX |
1109665 |
Apr 1968 |
GBX |
1128192 |
Sep 1968 |
GBX |
Continuations (1)
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Number |
Date |
Country |
Parent |
729689 |
Jul 1991 |
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