Magnetic recording medium

• US 4,585,702 A
• Filed: 06/30/1983
• Issued: 04/29/1986
• Est. Priority Date: 06/30/1983
• Status: Expired due to Term

• Current Assignee: Union Carbide Corporation (Dow, Inc.)
• Original Assignee: Union Carbide Corporation (Dow, Inc.)
• Inventors: Koleske, Joseph V., Osborn, Claiborn L.
• Primary Examiner(s): Robinson, Ellis P.
• Application Number:
  US06/509,390
• Time in Patent Office: 1,034 Days
• Field of Search: 428/900, 428/694, 428/425.9, 427/44, 427/128, 422/131, 422/132, 360/134-136, 528/49, 528/75, 252/62.54
• US Class Current: 428/425.9
• CPC Class Codes: C08G 18/6725 containing ester groups other than acrylate or alkylacrylate ester groups
• CPC Class Codes: C08G 18/8175 with esters of acrylic or alkylacrylic acid having only one group containing active hydrogen
• CPC Class Codes: G11B 5/7021 containing a polyurethane or a polyisocyanate
• CPC Class Codes: Y10S 428/90 Magnetic feature
• CPC Class Codes: Y10T 428/31609 Particulate metal or metal compound-containing

Abstract

Described is a magnetic recording medium comprising a substrate and a magnetic recording layer therein comprising a binder and magnetic particles, the binder comprising a lactone-acrylate adduct.

Claims

1. A magnetic recording medium comprising a substrate and a magnetic recording layer thereon comprising a cured binder and magnetic particles, the binder comprising the reaction product of a lactone-acrylate adduct with:

(a) a multi-functional isocyanate;

(b) a polyol and a multi-functional isocyanate;

(c) a polyol, a multi-functional isocyanate, and a hydroxyalkyl acrylate;

or

(d) a polyol, a multi-functional isocyanate, a hydroxyalkyl acrylate and a reactive solvent.

2. A magnetic recording medium as defined in claim 1 wherein the lactone-acrylate adduct is prepared by reacting a lactone with an hydroxyalkyl acrylate.

3. A magnetic recording medium as defined in claim 2 wherein the lactone is characterized by the following formula:

##STR7## wherein the R'"'"'s are independently hydrogen or alkyl of from 1 to 12 carbon atoms, and x is from 4 to 7.

4. A magnetic recording medium as defined in claim 3 wherein the lactone is epsilon-caprolactone.

5. A magnetic recording medium as defined in claim 2 wherein the hydroxyalkyl acrylate is selected from 2-hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, 2-hydroxy-3-chloro-propylacrylate, 2,3-dihydroxy propyl acrylate, or mixtures thereof.

6. A magnetic recording medium as defined in claim 5 wherein the hydroxyalkyl acrylate is hydroxyethyl acrylate.

7. A magnetic recording medium as defined in claim 1 wherein the binder comprises the reaction product of a lactone-acrylate adduct with a multi-functional isocyanate.

8. A magnetic recording medium as defined in claim 7 wherein the multi-functional isocyanate is selected 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, isophorone diisocyanate, 4,4'"'"'-diphenylmethane diisocyanate, di(2-isocyanatoethyl)-bicyclo (2.2.1) hept-5-ene-2,3-dicarboxylate, 3,5,5-triethyl-1-isocyanato-3-isocyanato-methylcyclohexane, 1,6-hexamethylene diisocyanate, m- and p-xylene diisocyanate, cyclohexane-1,4-diisocyanate, dicyclohexyl-4,4'"'"'-methane diisocyanate, tetramethylene diisocyanate, cyclopentylene-1,3-diisocyanate, 1,3-diisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, hexamethylene diisocyanate, 3,3'"'"'-dimethyl-4,4'"'"'-diphenylmethane diisocyanate, 4,4'"'"'-diphenylmethane diisocyanate, 3,3'"'"'-dimethylbiphenylene diisocyanate, 4,4'"'"'-biphenylene diisocyanate, 3,3'"'"'-dimethoxy 4,4'"'"'-dimethyl 4,4'"'"'-biphenylene diisocyanate, durene diisocyanate, 1-phenoxy-2,4-phenylene diisocyanate, 1-tert-butyl-2,4-phenylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,3,5-benzene triisocyanate, 2,4,6-toluene triisocyanate toluene, or mixtures thereof.

9. A magnetic recording medium as defined in claim 1 wherein the binder comprises the reaction product of a lactone-acrylate adduct with a multi-functional isocyanate and a polyol.

10. A magnetic recording medium as defined in claim 9 wherein the polyol is selected from the group consisting of a polyether polyol, a polycaprolactone polyol, a polyester polyol, an acrylic polyol, a vinyl polyol, a polymer/polyol, or mixtures thereof.

11. A magnetic recording medium as defined in claim 10 wherein the polyether polyol is selected from the group consisting of a propylene oxide polyol, an ethylene oxide polyol, a propylene oxide polyol capped with ethylene oxide, ethylene oxide/propylene oxide copolymers, a tetramethylene oxide polyol and a polymer/polyol.

12. A magnetic recording medium as defined in claim 9 wherein the polyol is a polymer polyol.

13. A magnetic recording medium as defined in claim 9 wherein the polyol is a polyepsilon-caprolactone polyol.

14. A magnetic recording medium as defined in claim 9 wherein the polyol is a polyester polyol.

15. A magnetic recording medium as defined in claim 9 wherein the polyol is an acrylic polyol.

16. A magnetic recording medium as defined in claim 9 wherein the polyol is a vinyl polyol.

17. A magnetic recording medium as defined in claim 1 wherein the binder comprises the reaction product of a lactone-acrylate adduct with a polyol, a multifunctional isocyanate and an hydroxyalkyl acrylate.

18. A magnetic recording medium as defined in claim 17 wherein the hydroxyalkyl acrylate is as defined in claim 5.

19. A magnetic recording medium as defined in claim 1 wherein the binder comprises the reaction product of a lactone-acrylate adduct with a polyol, a multifunctional isocyanate, and an hydroxyalkyl acrylate in a reactive solvent.

20. A magnetic recording medium as defined in claim 19 wherein the reactive solvent is of the following formula:

##STR8## wherein X is hydrogen or methyl and R₂ can be substituted or unsubstituted alkyl, cycloalkyl, alkenyl, aryl, or aralkyl, wherein the substituent can be alkyoxy, hydroxyl, cyano, or amino, or R₂ can be carbamoyloxy alkyl which can be N-alkyl substituted.

21. A magnetic recording medium as defined in claim 19 wherein the reactive solvent is a multi-functional alkyl acrylate.

22. A magnetic recording medium as defined in claim 21 wherein the reactive solvent is 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tetramethyleneglycol diacrylate, esterdiol-204-diacrylate, trimethylolpropane triacrylate, triethyleneglycol diacrylate, the diacrylate of esterdiol 204, or mixtures thereof.

23. A magnetic recording medium as defined in claim 19 wherein the reactive solvent is N-vinylpyrrolidone.

24. A magnetic recording medium as defined in claim 19 wherein the reactive solvent is a lactone-acrylate adduct reacted with a multi-functional isocyanate.

25. A magnetic recording medium as defined in claims 1 or 7 or 9 or 17 or 19 which contains a non-reactive solvent.

26. A magnetic recording medium as defined in claim 24 wherein the solvent is cyclohexanone, toluene, methyl isobutyl ketone, tetrahydrofuran, methyl amyl ketone, ethoxy ethyl acetate, and mixtures thereof.

27. A magnetic recording medium as defined in claims 1 or 7 or 9 or 17 or 19 or 25 which contains the reaction product of a polyol, a multi-functional isocyanate and an hydroxyalkyl acrylate and/or the reaction product of an hydroxyalkyl acrylate and multi-functional isocyanate.