Claims
- 1. A magnetic toner comprising a binder resin and a magnetic material, said binder resin comprising a non-crosslinked styrene polymer, a non-crosslinked styrene copolymer or a mixture of these and a polyolefin, wherein:
- said binder has, in its molecular weight distribution pattern measure by gel permeation chromatography (GPC), at least one maximal point (peak) in each region of a low molecular weight from 5,000 to 20,200 and of a high molecular weight from 200,000 to 1,000,000, where a height H1 of a maximum peak in the low molecular weight region, a height H3 of a maximum peak in the high molecular weight region and a height H2 of minimal point between both of said peaks satisfy the relationship H1:H2:H3 of 3-25:1:1.5-12 and has a weight average molecular weight Mw and a number average molecular weight Mn of a value Mw/Mn from 15 to 80 and
- said binder resin is a binder resin prepared by dissolving in a solvent a low molecular weight polymer or copolymer having in the molecular weight distribution pattern measured by GPC, a maximal point (peak) in the region of a molecular weight from 5,000 to 20,200 and having a value Mw/Mn of not more than 3.0, a high molecular weight polymer or copolymer having a maximal point (peak) in the region of a molecular weight from 200,000 to 1,000,000 and containing not more than 30% by weight of components having a molecular weight from 500 to 100,000, and said polyolefin; and removing said solvent therefrom.
- 2. The magnetic toner according to claim 1, wherein said binder resin has in its molecular weight distribution measured by GPC a value Mw/Mn of from 22 to 60.
- 3. The magnetic toner according to claim 1, wherein said binder resin has in its molecular weight distribution pattern measured by GPG a peak in each region of a low molecular weight of from 8,000 to 16,000 and of a high molecular weight of from 400,000 to 800,000.
- 4. The magnetic toner according to claim 1, wherein said binder resin has in its molecular weight distribution pattern measured by GPC the relationship H1:H2:H3 of 6-20:1:3-9.
- 5. The magnetic toner according to claim 1, wherein said binder resin has in its molecular weight distribution pattern measured by GPC a value Mw/Mn of from 22 to 60, and a maximal point (peak) in each region of a low molecular weight of from 8,000 to 16,000 and of a high molecular weight of from 400,000 to 800,000, where a height H1 of a maximum peak in the low molecular weight region, a height H3 of a maximum peak in the high molecular weight region and a height H2 of a minimal point between both of said peaks satisfy the relationship H1:H2:H3 of 6-20:1:3-9.
- 6. The magnetic toner according to claim 1, wherein said low molecular weight polymer or copolymer, said high molecular weight polymer or copolymer and said polyolefin are dissolved during heating.
- 7. The magnetic toner according to claim 1, wherein said low molecular weight polymer or copolymer is a polymer or copolymer prepared by solution polymerization.
- 8. The magnetic toner according to claim 1, wherein said low molecular weight polymer or copolymer is a polymer or copolymer prepared by solution polymerization, and the same solvent as used in said solution polymerization is used as said solvent for dissolving said high molecular weight polymer or copolymer and said polyolefin.
- 9. The magnetic toner according to claim 1, wherein said high molecular weight polymer or copolymer is a polymer or copolymer prepared by suspension polymerization.
- 10. The magnetic toner according to claim 1, wherein said high molecular weight polymer or copolymer is prepared by fractionation so as to contain said 30% or less by weight of the component with a molecular weight of from 500 to 100,000.
- 11. The magnetic toner according to claim 10, wherein said high molecular weight polymer or copolymer is prepared by fractional precipitation.
- 12. The magnetic toner according to claim 1, wherein said polyolefin is contained in an amount of from 0.1 part by weight to 20 parts by weight based on 100 parts by weight of said binder resin.
- 13. The magnetic toner according to claim 1, wherein said polyolefin is contained in an amount of from 0.1 part by weight to 10 parts by weight based on 100 parts by weight of said binder resin.
- 14. The magnetic toner according to claim 1, wherein said magnetic material is contained in an amount of from 60 parts by weight to 110 parts by weight based on 100 parts by weight of said binder resin.
- 15. The magnetic toner according to claim 1, wherein said magnetic material is contained in an amount of from 65 parts by weight to 100 parts by weight based on 100 parts by weight of said binder resin.
- 16. The magnetic toner according to claim 1, wherein said polyolefin has a weight average molecular weight of from 2,000 to 30,000.
- 17. The magnetic toner according to claim 1, wherein said polyolefin has a weight average molecular weight of from 5,000 to 18,000.
- 18. The magnetic toner according to claim 1, wherein said polyolefin comprises a polypropylene having a weight average molecular weight of from 2,000 to 30,000.
- 19. The magnetic toner according to claim 1, wherein said binder resin contains from 5% to 30% of a high molecular weight component present in the region of a molecular weight of not less than 500,000.
- 20. The magnetic toner according to claim 1, wherein said binder resin contains from 7% to 25% of a high molecular weight component present in the region of a molecular weight of not less than 500,000.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3-147392 |
Jun 1991 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 07/899,242 filed Jun. 16, 1992 abandoned.
US Referenced Citations (11)
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Non-Patent Literature Citations (1)
Entry |
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Continuations (1)
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Number |
Date |
Country |
Parent |
899242 |
Jun 1992 |
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