CA1287836C - Magnetic recording medium - Google Patents
Magnetic recording mediumInfo
- Publication number
- CA1287836C CA1287836C CA 565958 CA565958A CA1287836C CA 1287836 C CA1287836 C CA 1287836C CA 565958 CA565958 CA 565958 CA 565958 A CA565958 A CA 565958A CA 1287836 C CA1287836 C CA 1287836C
- Authority
- CA
- Canada
- Prior art keywords
- diisocyanate
- compound
- terminals
- molecular weight
- polyurethane
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- Paints Or Removers (AREA)
- Polyurethanes Or Polyureas (AREA)
Abstract
ABSTRACT:
A magnetic recording meidum which comprises a non-magnetic support and a magnetic layer thereon comprising a binder and powder of a ferromagnetic substance dispersed in the binder, the binder comprising a crosslinked product of a polyurethane having an average molecular weight of 900 to 50,000 and comprising at least one unit of the formula (I):
(I) in which R1, R2 and R4 each are an alkylene, R3 is a hydrocarbon group derived from a di-isocyanate compound and R5 is hydrogen or methyl, in one molecular thereof and having -OH, -NCO or -OOC-CR5=CH2 at both terminals of the main chain thereof, provided that the terminals of the main chain are not -NCO when the molecular weight of the polyu.rethane ranges from 900 to 10,000. The polyurehtane resin can be prepared by using as a starting material a polymerizable dihydorxyl compound of the general formula (II):
A magnetic recording meidum which comprises a non-magnetic support and a magnetic layer thereon comprising a binder and powder of a ferromagnetic substance dispersed in the binder, the binder comprising a crosslinked product of a polyurethane having an average molecular weight of 900 to 50,000 and comprising at least one unit of the formula (I):
(I) in which R1, R2 and R4 each are an alkylene, R3 is a hydrocarbon group derived from a di-isocyanate compound and R5 is hydrogen or methyl, in one molecular thereof and having -OH, -NCO or -OOC-CR5=CH2 at both terminals of the main chain thereof, provided that the terminals of the main chain are not -NCO when the molecular weight of the polyu.rethane ranges from 900 to 10,000. The polyurehtane resin can be prepared by using as a starting material a polymerizable dihydorxyl compound of the general formula (II):
Description
~ 7 ~
. .
Magnetic Recording Medlum ., :, . . .
.. .,, , .. ~.. ~ .
:, . - : .
~BACKGROUND OF THE INVENTION
Field of~the Invention ` ~ The present invention relates to a magnetîc ;
recording medium, and more particularly to:a magnetic record~ing medium ïn ~hich.a~radiation-curable compound is osed~as a binder and which is 1mproved~in:durability.
(Z) D~scriptiOn~o~ the Prior ~r~
As~a:~method of producing magnetic recording media generally~used widely, ~there has been a method in which at }east~one thermoplastic resin such as vinyl:
chloride-vinyl~acetate resin,:~vinyl chloride-viny1idene chloride resi~n, cellulose ~esin, ace:tal resin, urethane ~ :
res1n, acrylonl~trile-butadiene~resin~ etc. is~used,:either : ~ :
::~:: :
.
3~
.
singly or in combination, a~ a blnde~. Thl~ m~thod, however, has th~ drawback that a maynetlc layer obtained has poor abrasion resistance, resulting in contamination of a feed passage of a magnetic tape.
There has been also known a method in which a thermoplastic resin such as melamine resin and urea resin is:used, or a~method in which a binder capable of being crossllnked by a che=ical reaction, for instance, an - :
isocyanate compound or an epoxy compound is added to the thermoplastic~resin.; The;use~of~the crosslinkable binder, however, has~the fallowing drawbacks (1) and (2).
The~storaqe stabil~ity of a~xesin~solution having =agnetic~powd~er dispersed therein is poor, na=ely, the pot life~o:the solution lS~ short, and it:Ls therefore ~ i=possible to:=alntain the uni~formity of physiaal : properties~of a magnetic coating liquid and hence the ; :unL~or=ity of quality of magnetlc tapes. ~ :~
~2)~ A~heat treatment~step is: required for curing a ;
coating a~ter~:coating and:~dryLng;s~teps, and it takes , ~ ~, : -:` : ::
~ 37 83~
long time ~o obtain a ~inished produ~t.
As a means ~or overcoming these drawbacks, a method of producing magnetic media in which acrylic acid ester oligomer and monomer are used as a binder and curing after drying is effected by elec~tron beams is disclosed in Japanese patent:publication No.~ 47-12423 (1972~ Japaneae Patent Application Laid-Open (KOKAI) Nos. 47-13639 ~1972)~, 47-13104 (1972), 50-77433 (1975) and 57-130229 (1982),~etc.~ According to the : :
disclosed method,: however, it has b:een impossible to obtain a magnetic~recording medium~having high electrical characteri~stics, mechani~oal ~propertles or durabi~lity.
Recently,;there has:been a particular demand~
for;a hLgh degree of electrical~characteri~stics, and there has~:therefore~been an increasing demand for a magnètic coating liquid with~good dispersion properties of ferromagnetic~powder. If the~dispers1on properties of the ferromagnetic powder~are;:~poor, a~lowering of output;or generation~of nois~ would result.
.
, . . . ~, . , ~ .......... . . . .
, .~ : . . . . . . . .. . . .
. .
7~
, Besides, th~ onventional method in which the electron beams curing is used has the drawback that when the content of a magnetic substance is increased for high-density recording~ the storage stability of the magnetic coating liquid becomes poor and the electrical characteristics of the magneti tape obtained are unsatisfactory ~or practica~l use. In addition, for prolonging the recording time of the magnetic tape, it is necessary that the support be thinner and the . ~
mechanical properties of the magnetic layer be improved.
Thusj with the recent~wide spread of magnetic recording media such as video tapes, floppy disks, etc., severe use conditions have come~to be imposed on the magnetic recording media, but a magnetic layer provided ~with ~echanical properties ~sufficient for the se~ere ~onditions has~ not been a~tained.
:: ::
: ~ :
; DISCLOSURE~OF THE~IN~ENTION
The present inve~ntor~ has made various studies : :
:
, ~
:
,: ~
. .
7~
for overcoming the drawbacks of the prlor art such as the method in which a thermoplastic resin, a thermosettiny resin or the like i5 used as a binder, the rnethod ln whlch a binde~ capable o~ b~ing cros~llnked by ~ chernlcal reaction is added, the method in which a binder curable through electron beams crosslinking is used, etc., and~ as a result of the studies, the present inventlon has been attained.
According to the present invention, there is provided a magnetic recording medium which comprises a ~ non-magnetic support and a magnetic layer, coated on the ; support, comprising a binder and powder of a ferromagnetic substance dispersed in the binder, said binder comprising a crosslinked product of a polyurethane having an average molecular weight of 900 to 50,000 and comprising at least one unit having the formula (I) in one molecule thereof and having -OH, -NCO or -OOC-CR5=CH2 at both terminals of the main chain thereo, provided that the terminals of the main chaln thereof are not -NCO when the molecular weight of the polyurethane ranges from 900 to less than 1 0, 0 0 0 . , - N -- c - O--R, ~ R 2--O '- C - N --~ H O ~ C = 0 ~ ~ I ) - ~ Nll O 0 1~5 11 ~1: 11 1 3--N--C-û--R ~--O--C--C =CII z ~: ~
:
~ . , ~ . . , , ,, - . , , :
.': - . - ' .......... '. ~ . ' ' ~ . ,' . .
: ~ : . , ~ , . . .
7~
- 6 - 65702~307 in which R1, R2 and Ra each are an alkylene, ~3 is a hyd~ocarbon group derived rom a diisocyanate compound and ~5 i~ hydrogen or methyl.
Another aspect of the present invention provide~ a process for producing the mag~etic reaordiny medium, which p~c~
comprises:
applying a magnet.ic paint aomprislny the binder, the ~erromagnetic substance powder and a solvent to a surface of the support, drying off:the solvent from the paint, and applying radiation to the dried paint, thereby cross-linking the polyurethane.
: Furthermore, according to the present invention, there ~is provided a polymeri~able dihydroxyl compound having the follow-i~g general formula (II):
HO - Rl - N - R2 OH
~ 1 :~ ~ C--O
I
NH H O R5 (II) : R3 N C o - R4 - 0 - C - C = CH2 in which Rl, R2~and R4 each are an alkylene, R3 is a hydrocarbon group and R5 is hydrogen or methyl. R3 is preferably a hydro-carbon group derived from a diisocyanate compound~
With respect to ~he polyurethane used ln the present invention, there are two modes: in one mode, said polyurethane : ~ is~a urethane oligomer having a molecular weight of 900 to less ; ~ ~ than;10,000, and in the other mode, said polyurethane is a poly- :
:~
:: :
:-.~.: : . . , , . : : : , . , 7~3f;
urethane having a molecular weight of 10, oao ~0 50,000.
When the urethane oligomer is used, the present lnven-tion relates to a magnetic recording medium which comprises a non-magnetic ~uppo~t and a magn~tic layer, coated on the sup~D~t, comprising a binder and powder of a fer~omagnekic sub~ta~c~ dl~
per~ed in the binder, ~aid binder comprising a aro~slinked product of a urethane oligomer having a molecular weight (determined by analysis of terminal unctional groups of molecule) of 900 to ; less than 10~000, comprising at least one unit having the above-mentioned formula (I) in one molecule thereof and having -OH or - 0 - C - C = CH
.. 2 ,~ O
at both terminals of the main chain thereof.
The urethane oligomer accordin~ to the first mode has a molecuIar weight (determined by analysis of terminal functional groups of molecule) o~ 900 to less than 10,000.
The urethane oligomer can be produced as follows.
(i) First, a dihydroxyl compound having the following general ormula (II):
HO - Rl - N - R2 ~ OH
C=0 (II) MH O " 15 C o R4 C C CH2 ~:; 20 in ~hich Rl, R2 and R4 each are an alkylene, R3 is a hydrocarbon group derived from:a diisocyanate compound and R5 is -H or -CH3, ~ :' :: :
,:
- . , . , . : . ., :.
;:
~ ~37~33~
~ 8 - 65702-307 is reacted with a diisocyanate compound to form a compound ~i e., prepolymer) having an isocyanate group at both terminals o the molecule. In this case, the diisocyanate compound is used in an excess molar quantity relative to the dihydroxyl compound In consideration o~ the easiness o~ handli.ny o~ the product arld t~
necessity for malciny th~ mol~cular weight o~ the objective ure~
thane oligomer less than 10,000, it is preerable to use the diisocyanate compound in an amount o~ about 1.5 to 2.0 moles per mole of the dihydroxyl compound.
(ii) Next, the prepolymer having an isocyanate group at both terminals of the molecule obtained in (i) above is reacted with a polyol (e.g., diol) compound, whereby a urethane oligomer having a molecular weight of 900 to less than 10,000, comprising at least one unit having the above-mentioned formula (I) in one molecule ~nd having -OH at both terminals of the main chain can-~be ; obtained. In this case, also,- the polyol compound is used in an exsess molar quantity relative to the prepolymer compound having an isocyanate group at both terminaIs o~ the molecule. On the same ground as in (i) above, it is preferable to set the molar ratio of the isocyanate-terminated compound to the polyol compound in the range of about 1:1.5 to 1:2.0 (iii~ Further, the terminals of ~he urethane oligomer having -OH at both terminals of the main chain ohtained in (ii) above may be converted into tmeth~acryloyl, whereby a urethane oligomer having ,~
:, . ~ , ,~: ' ; :
7~33~
- O - C - C = CH2 ,'.
1 .
o at both terminal~ o~ the main chain thereof can be obtained.
The conver~ion into ~meth)acryl~yl can be carried out by reacting the urethane oligomer having -OH at both terminals ; o~ the main chain obtained in (il) with a diisocyanate compound to once convert both terminals of the main chain into isocyanate : groups, and then reacting the resultant product with a compound having a (meth)acrylic double~bond and an isocyanate-reactive , group in the molecule, thereby obtaining the objective urethane ~ ~10 oligomer.
.~ Alternatively, the conversion~into:(meth)acryloyl ~may be~ carried out by raacting the urethane ol~igomer obtained : in ~ii) with (meth)a~rylic acid or:a Iower alkyl ester there-of.
:
:
~: ~
. . -: - . - . :
783~
. :
:: When the polyurethane havlng a molecular ~e~yh~
of l0,000 to 50,000 ls used, the present inv~ntJ.on relates to a magnetic recording medium whlch cornprise~
a non-magnetic support and a magnetic layer, coated on the support, comprising a binder and powder of a ferromagnetic substance dispersed in the blnder, said binder comprising a crosslinked product of a~polyurethane resin having a : molecular weight (determined by gel permeation chromato-graphyl of l0~,000 to 50,000, comprising at least one unit ::
having the above-mentioned general formula (I) in one :: : ; Rs molecule thereof and having -OH, -NCO or - 0:-C - C ~ CH -o at both term`inals of the main chain thereof.
The polyurethane resin used as a -binder in the present invention has a number average molecular : :~
welght, as det~ermined by gel:permeation chromatography (column: Shodex* A-803jA-804 mlxture, produced by Showa Denko K.X.), o~10,000 to 50,000,;preferab1y 10,000 to 35,000~ If the number average molecular weight of the polyurethane~resin is less than l0,000~, the:mechanical~
: properties of~the magnet1c layer and the adheslon of the layer to the support are not~very good.: On the other hand, if *Trademark :
: :
7~3~;
the number average molecular weighk exceeds 50,000, the dispersibility of the magnetic powder ls worsened~
The polyurethane re~ln according to the pr~.sent invention can basically be prepared by the following methods.
(l) F~rst, a novel dihydroxyl compound having the following general formula (II):
-~ HO - Rl - N- R2- OH
C = O
( Il NH O O Rs R~ - N - C-O - Rk~- O - C- C =CH2 :
1n which Rl, R2 and R4 ea¢h are an alkylene, R3 is a :: hydrocarbon gorup derived from :a di-isocyanate compound and R5 is -H~o~r -CH3, is reacted with an excess molar ~uantity of a di-isocyanate ~ompound to form a compound .
having:~ Isocyanate group at:~both terminals of the molecule thereo~f~ In consideration of the easiness of ~he~reaction process and the easiness of handling of the reaction product, it is preferable to use about 1.5 to 2.0 moles of the~di-isocyanate compound per mole oÇ the dihydroxyl compound.: ~ :
Wext,~the~compound having the isocynate group at both terminals of the molecule:ther of is react d with . ~
~: :
~:
:
:~ :
: . . . " . : ~ .
.~ . . . . . .
;,:: :"., '. : - ' 37~
an excess molar quantity of a polyol compound to form a urethane oligomer having -OH at both terminals o~
the maLn chaln thereoe. ~n this case, al~o~ lt l~ ~reE~rable to use the hydroxyl-containlng compound ln an amount o~ about 1.5 to 2.0 moles per mole of the isocyante-terminated compound.
~ Further, the urethane oligomer obtained as above :- is reacted with a di-isocyanate compound, whereby a polyuret~ane resin having -OH or -NCO at both terminals ~ ~ , of the main chain thereof can be obtained. In this case, in addition to the urethane oligomer having the hydroxyl group at both terminals of the molecule thereof, ~ : : other polyol component may be jointly used. The molar : ~ ratio of OH¦NCO of the polyol and the di-isocyanate compound is~in:the range of 1/0.85 to 1/1.15, preferably : : ~
~ O / O a 9 5 to 1.0/1.05.
, Rs The polyurethane resin having - ~ -C - C = GHz . O
at both terminals of the main chain thereof can be obtained:
by reacting the above-mentioned polyurethane resin having NCO at both terminals of the main chain thereof with ~ a compound having a (meth)aoryloyl double~bond and ; an isocyanate-reactive group in the molecule thereof, the ::
: ~ :
.~ : . . - . , . . ~ . .. . .
. .
Magnetic Recording Medlum ., :, . . .
.. .,, , .. ~.. ~ .
:, . - : .
~BACKGROUND OF THE INVENTION
Field of~the Invention ` ~ The present invention relates to a magnetîc ;
recording medium, and more particularly to:a magnetic record~ing medium ïn ~hich.a~radiation-curable compound is osed~as a binder and which is 1mproved~in:durability.
(Z) D~scriptiOn~o~ the Prior ~r~
As~a:~method of producing magnetic recording media generally~used widely, ~there has been a method in which at }east~one thermoplastic resin such as vinyl:
chloride-vinyl~acetate resin,:~vinyl chloride-viny1idene chloride resi~n, cellulose ~esin, ace:tal resin, urethane ~ :
res1n, acrylonl~trile-butadiene~resin~ etc. is~used,:either : ~ :
::~:: :
.
3~
.
singly or in combination, a~ a blnde~. Thl~ m~thod, however, has th~ drawback that a maynetlc layer obtained has poor abrasion resistance, resulting in contamination of a feed passage of a magnetic tape.
There has been also known a method in which a thermoplastic resin such as melamine resin and urea resin is:used, or a~method in which a binder capable of being crossllnked by a che=ical reaction, for instance, an - :
isocyanate compound or an epoxy compound is added to the thermoplastic~resin.; The;use~of~the crosslinkable binder, however, has~the fallowing drawbacks (1) and (2).
The~storaqe stabil~ity of a~xesin~solution having =agnetic~powd~er dispersed therein is poor, na=ely, the pot life~o:the solution lS~ short, and it:Ls therefore ~ i=possible to:=alntain the uni~formity of physiaal : properties~of a magnetic coating liquid and hence the ; :unL~or=ity of quality of magnetlc tapes. ~ :~
~2)~ A~heat treatment~step is: required for curing a ;
coating a~ter~:coating and:~dryLng;s~teps, and it takes , ~ ~, : -:` : ::
~ 37 83~
long time ~o obtain a ~inished produ~t.
As a means ~or overcoming these drawbacks, a method of producing magnetic media in which acrylic acid ester oligomer and monomer are used as a binder and curing after drying is effected by elec~tron beams is disclosed in Japanese patent:publication No.~ 47-12423 (1972~ Japaneae Patent Application Laid-Open (KOKAI) Nos. 47-13639 ~1972)~, 47-13104 (1972), 50-77433 (1975) and 57-130229 (1982),~etc.~ According to the : :
disclosed method,: however, it has b:een impossible to obtain a magnetic~recording medium~having high electrical characteri~stics, mechani~oal ~propertles or durabi~lity.
Recently,;there has:been a particular demand~
for;a hLgh degree of electrical~characteri~stics, and there has~:therefore~been an increasing demand for a magnètic coating liquid with~good dispersion properties of ferromagnetic~powder. If the~dispers1on properties of the ferromagnetic powder~are;:~poor, a~lowering of output;or generation~of nois~ would result.
.
, . . . ~, . , ~ .......... . . . .
, .~ : . . . . . . . .. . . .
. .
7~
, Besides, th~ onventional method in which the electron beams curing is used has the drawback that when the content of a magnetic substance is increased for high-density recording~ the storage stability of the magnetic coating liquid becomes poor and the electrical characteristics of the magneti tape obtained are unsatisfactory ~or practica~l use. In addition, for prolonging the recording time of the magnetic tape, it is necessary that the support be thinner and the . ~
mechanical properties of the magnetic layer be improved.
Thusj with the recent~wide spread of magnetic recording media such as video tapes, floppy disks, etc., severe use conditions have come~to be imposed on the magnetic recording media, but a magnetic layer provided ~with ~echanical properties ~sufficient for the se~ere ~onditions has~ not been a~tained.
:: ::
: ~ :
; DISCLOSURE~OF THE~IN~ENTION
The present inve~ntor~ has made various studies : :
:
, ~
:
,: ~
. .
7~
for overcoming the drawbacks of the prlor art such as the method in which a thermoplastic resin, a thermosettiny resin or the like i5 used as a binder, the rnethod ln whlch a binde~ capable o~ b~ing cros~llnked by ~ chernlcal reaction is added, the method in which a binder curable through electron beams crosslinking is used, etc., and~ as a result of the studies, the present inventlon has been attained.
According to the present invention, there is provided a magnetic recording medium which comprises a ~ non-magnetic support and a magnetic layer, coated on the ; support, comprising a binder and powder of a ferromagnetic substance dispersed in the binder, said binder comprising a crosslinked product of a polyurethane having an average molecular weight of 900 to 50,000 and comprising at least one unit having the formula (I) in one molecule thereof and having -OH, -NCO or -OOC-CR5=CH2 at both terminals of the main chain thereo, provided that the terminals of the main chaln thereof are not -NCO when the molecular weight of the polyurethane ranges from 900 to less than 1 0, 0 0 0 . , - N -- c - O--R, ~ R 2--O '- C - N --~ H O ~ C = 0 ~ ~ I ) - ~ Nll O 0 1~5 11 ~1: 11 1 3--N--C-û--R ~--O--C--C =CII z ~: ~
:
~ . , ~ . . , , ,, - . , , :
.': - . - ' .......... '. ~ . ' ' ~ . ,' . .
: ~ : . , ~ , . . .
7~
- 6 - 65702~307 in which R1, R2 and Ra each are an alkylene, ~3 is a hyd~ocarbon group derived rom a diisocyanate compound and ~5 i~ hydrogen or methyl.
Another aspect of the present invention provide~ a process for producing the mag~etic reaordiny medium, which p~c~
comprises:
applying a magnet.ic paint aomprislny the binder, the ~erromagnetic substance powder and a solvent to a surface of the support, drying off:the solvent from the paint, and applying radiation to the dried paint, thereby cross-linking the polyurethane.
: Furthermore, according to the present invention, there ~is provided a polymeri~able dihydroxyl compound having the follow-i~g general formula (II):
HO - Rl - N - R2 OH
~ 1 :~ ~ C--O
I
NH H O R5 (II) : R3 N C o - R4 - 0 - C - C = CH2 in which Rl, R2~and R4 each are an alkylene, R3 is a hydrocarbon group and R5 is hydrogen or methyl. R3 is preferably a hydro-carbon group derived from a diisocyanate compound~
With respect to ~he polyurethane used ln the present invention, there are two modes: in one mode, said polyurethane : ~ is~a urethane oligomer having a molecular weight of 900 to less ; ~ ~ than;10,000, and in the other mode, said polyurethane is a poly- :
:~
:: :
:-.~.: : . . , , . : : : , . , 7~3f;
urethane having a molecular weight of 10, oao ~0 50,000.
When the urethane oligomer is used, the present lnven-tion relates to a magnetic recording medium which comprises a non-magnetic ~uppo~t and a magn~tic layer, coated on the sup~D~t, comprising a binder and powder of a fer~omagnekic sub~ta~c~ dl~
per~ed in the binder, ~aid binder comprising a aro~slinked product of a urethane oligomer having a molecular weight (determined by analysis of terminal unctional groups of molecule) of 900 to ; less than 10~000, comprising at least one unit having the above-mentioned formula (I) in one molecule thereof and having -OH or - 0 - C - C = CH
.. 2 ,~ O
at both terminals of the main chain thereof.
The urethane oligomer accordin~ to the first mode has a molecuIar weight (determined by analysis of terminal functional groups of molecule) o~ 900 to less than 10,000.
The urethane oligomer can be produced as follows.
(i) First, a dihydroxyl compound having the following general ormula (II):
HO - Rl - N - R2 ~ OH
C=0 (II) MH O " 15 C o R4 C C CH2 ~:; 20 in ~hich Rl, R2 and R4 each are an alkylene, R3 is a hydrocarbon group derived from:a diisocyanate compound and R5 is -H or -CH3, ~ :' :: :
,:
- . , . , . : . ., :.
;:
~ ~37~33~
~ 8 - 65702-307 is reacted with a diisocyanate compound to form a compound ~i e., prepolymer) having an isocyanate group at both terminals o the molecule. In this case, the diisocyanate compound is used in an excess molar quantity relative to the dihydroxyl compound In consideration o~ the easiness o~ handli.ny o~ the product arld t~
necessity for malciny th~ mol~cular weight o~ the objective ure~
thane oligomer less than 10,000, it is preerable to use the diisocyanate compound in an amount o~ about 1.5 to 2.0 moles per mole of the dihydroxyl compound.
(ii) Next, the prepolymer having an isocyanate group at both terminals of the molecule obtained in (i) above is reacted with a polyol (e.g., diol) compound, whereby a urethane oligomer having a molecular weight of 900 to less than 10,000, comprising at least one unit having the above-mentioned formula (I) in one molecule ~nd having -OH at both terminals of the main chain can-~be ; obtained. In this case, also,- the polyol compound is used in an exsess molar quantity relative to the prepolymer compound having an isocyanate group at both terminaIs o~ the molecule. On the same ground as in (i) above, it is preferable to set the molar ratio of the isocyanate-terminated compound to the polyol compound in the range of about 1:1.5 to 1:2.0 (iii~ Further, the terminals of ~he urethane oligomer having -OH at both terminals of the main chain ohtained in (ii) above may be converted into tmeth~acryloyl, whereby a urethane oligomer having ,~
:, . ~ , ,~: ' ; :
7~33~
- O - C - C = CH2 ,'.
1 .
o at both terminal~ o~ the main chain thereof can be obtained.
The conver~ion into ~meth)acryl~yl can be carried out by reacting the urethane oligomer having -OH at both terminals ; o~ the main chain obtained in (il) with a diisocyanate compound to once convert both terminals of the main chain into isocyanate : groups, and then reacting the resultant product with a compound having a (meth)acrylic double~bond and an isocyanate-reactive , group in the molecule, thereby obtaining the objective urethane ~ ~10 oligomer.
.~ Alternatively, the conversion~into:(meth)acryloyl ~may be~ carried out by raacting the urethane ol~igomer obtained : in ~ii) with (meth)a~rylic acid or:a Iower alkyl ester there-of.
:
:
~: ~
. . -: - . - . :
783~
. :
:: When the polyurethane havlng a molecular ~e~yh~
of l0,000 to 50,000 ls used, the present inv~ntJ.on relates to a magnetic recording medium whlch cornprise~
a non-magnetic support and a magnetic layer, coated on the support, comprising a binder and powder of a ferromagnetic substance dispersed in the blnder, said binder comprising a crosslinked product of a~polyurethane resin having a : molecular weight (determined by gel permeation chromato-graphyl of l0~,000 to 50,000, comprising at least one unit ::
having the above-mentioned general formula (I) in one :: : ; Rs molecule thereof and having -OH, -NCO or - 0:-C - C ~ CH -o at both term`inals of the main chain thereof.
The polyurethane resin used as a -binder in the present invention has a number average molecular : :~
welght, as det~ermined by gel:permeation chromatography (column: Shodex* A-803jA-804 mlxture, produced by Showa Denko K.X.), o~10,000 to 50,000,;preferab1y 10,000 to 35,000~ If the number average molecular weight of the polyurethane~resin is less than l0,000~, the:mechanical~
: properties of~the magnet1c layer and the adheslon of the layer to the support are not~very good.: On the other hand, if *Trademark :
: :
7~3~;
the number average molecular weighk exceeds 50,000, the dispersibility of the magnetic powder ls worsened~
The polyurethane re~ln according to the pr~.sent invention can basically be prepared by the following methods.
(l) F~rst, a novel dihydroxyl compound having the following general formula (II):
-~ HO - Rl - N- R2- OH
C = O
( Il NH O O Rs R~ - N - C-O - Rk~- O - C- C =CH2 :
1n which Rl, R2 and R4 ea¢h are an alkylene, R3 is a :: hydrocarbon gorup derived from :a di-isocyanate compound and R5 is -H~o~r -CH3, is reacted with an excess molar ~uantity of a di-isocyanate ~ompound to form a compound .
having:~ Isocyanate group at:~both terminals of the molecule thereo~f~ In consideration of the easiness of ~he~reaction process and the easiness of handling of the reaction product, it is preferable to use about 1.5 to 2.0 moles of the~di-isocyanate compound per mole oÇ the dihydroxyl compound.: ~ :
Wext,~the~compound having the isocynate group at both terminals of the molecule:ther of is react d with . ~
~: :
~:
:
:~ :
: . . . " . : ~ .
.~ . . . . . .
;,:: :"., '. : - ' 37~
an excess molar quantity of a polyol compound to form a urethane oligomer having -OH at both terminals o~
the maLn chaln thereoe. ~n this case, al~o~ lt l~ ~reE~rable to use the hydroxyl-containlng compound ln an amount o~ about 1.5 to 2.0 moles per mole of the isocyante-terminated compound.
~ Further, the urethane oligomer obtained as above :- is reacted with a di-isocyanate compound, whereby a polyuret~ane resin having -OH or -NCO at both terminals ~ ~ , of the main chain thereof can be obtained. In this case, in addition to the urethane oligomer having the hydroxyl group at both terminals of the molecule thereof, ~ : : other polyol component may be jointly used. The molar : ~ ratio of OH¦NCO of the polyol and the di-isocyanate compound is~in:the range of 1/0.85 to 1/1.15, preferably : : ~
~ O / O a 9 5 to 1.0/1.05.
, Rs The polyurethane resin having - ~ -C - C = GHz . O
at both terminals of the main chain thereof can be obtained:
by reacting the above-mentioned polyurethane resin having NCO at both terminals of the main chain thereof with ~ a compound having a (meth)aoryloyl double~bond and ; an isocyanate-reactive group in the molecule thereof, the ::
: ~ :
.~ : . . - . , . . ~ . .. . .
2~7 molar ratio of the reactants being about 1:2.
When the polyurethane resin haviny -OH ~k both terminals oE the maln chaLn thereo~ L~s used, the polyurethane resin ls r~acted wlth a d:L-i~ocya~ate compound in a molar ratio o~ about 1:2, thereby converting both terminals of the main chain into -NCO, and then the objective polyurethane resin can be obtained in the same manner as above. Alternatively, the terminals of the main chain may be converted into (meth)acryloyl by reaction with (meth)acrylic acid or a lower alkyl ester thereof.
While a method o~ preparing the objective polyurethane resin through a urethane oligomer (this term is synonymous with "urethane prepolymer") has been described above, a method based on direct urethane formation, as follows, may also be applied.
(2) The dihydroxyl compound having the above formula (II) or a mixture thereof with other polyol component is reacted directly with a di-isocyanate compound, whereby a polyurethane resin having -OH or -NCO~at both terminals of the main chain thereof can be obtained. In this case, the molar ratio of ON/NCO of the polyol and the di-isocyanate is in the range of l/0085 to 1/1.15, preferably loO/0~95 to l.O/1.05.
:~ `
: .
, . , ., . : -, ~ ~37~33~i ~ 6570Z-307 Conversion of both terminals of the main chain into ,5 - 0 C - C = CH
O
can be carried out by the above-mentioned method~
The dihyd~oxy:l. comE~ound having the above-mention~d general formula (II) ~or use as a starting material for khe ure-thane resin according to the pxesent invention is a novel compound, ~ and can basically be produced by the following steps.
;. (a) First, a diisocyanate compound of the formula:
~ OCN - R3 - NCO and a hydroxyalkyl (meth)acry~ate compound of the ;; " ,5 ~ lQ formula: HO - R4 - 0 - C - C = ~H2 are mixed with each other and -. stirred to produce an intermediate of the formula:
OCN - R3 - NH - CO - O - R4 - O - C - C = CH2. In this case, it is preferable to add a polymerization inhibitor such as hydro-: quinone and to;set khe temperature to 70C or lower. .
: : (b) Thenr an inert organic solvent such as methyl ethyl ketone is added to the reaction system, further a dialkanolamine of the formula:; HO - Rl - NH - R2 ~ OH is added to the system, and the resultant mixture is stirred. In this case it is pre-ferable to add the dialkanolamine dropwise to the system and to 20 - - set the temperature of the system to 10C or lower.
The reaction time is not particularly limitedt , 33~
and depends on the reactant compounds. TO achieve a certain degree o~ y.L~ld~ howeve~ h~ reac tibn ~im~ is ordinarily 2 to'5 hours lh ~a), and 3 to 10 hours in (b~
Referring to the starting compounds for use in the production o~ the polymerizable dihydroxyl compound, the di-isocyanate compound may be, for example, an aromatic di-isocyanate such as m-phenylene diisocyanate, p-phenylene diisocyanate, l-chloro-2,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthtylene dlisocyanate, diphenylmethane-4,4'-dilsocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, etc.; an aliphatic dl-isocyanate such as ethane diisocyanate, propane diisocyanate, butane diisocyanate, pentane dilsocyanate, hexane diisocyanate, heptane diisocyanate, ;~
octane diisocyanate, nonane diisocyanate, decane dlisocyanate, etc.; isophorone dlisocyanate, or the like.
Among others, 2,4-tolylene dlisocyanate and isophorone diisocyanate, in~which the two isocyanate groups differ in reactivity, are preferred.
This is because it is advantageous that the hydroxyalkyl (meth)acrylate reacts mainly wlth one of the two isocyanate groups of the di-isocyanate compound in the flrst stage reaction of the two compounds, for a higher :~ ~
, .~
~ ~ : : . , : . , :
.: : . :
~ ~3'7~
- 16 ~ 65702-307 yield of the final objective product.
The hydroxylalkyl (meth)acrylate has preferably Z to 12, more preferably 2 to 5 carbon atoms in the alkyl moiety and may be, ~or example, hydro~yethyl methacrylate, hydroxypxopyl (meth)acrylate, hydro~ybu~yl ~mekh)ac~yl~-te, hyd~oxyh~Yyl (meth) acrylate or the like. The dialkanolamine has pre~erably 2 to 8, more preferably 2 or 3 carbon atoms in each o~ the alkanol moiety and may be, ~or example, diethanolamine, dipropanalamine, di-butanolamine, ~hexanolamine or the like.
The diisocyanate compounds which can be used for preparation of the polyurethane from the dihydroxyl compound hav-ing the general formula (II), either through preparation of a urethane oligomer or directly, may include, for example, aromatic - diisocyanate such as m-phenylene diisocyanate, p-phenylene diiso-cyanate, l-chloro-2,4-phenylene diisocyanate, 2,4-tolylene diiso-cyanate~ 2,6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyl-4,4'-biphenylene ~ diisocyanate, etc.; aliphatic diisocyanates such as ethane diiso-;~ cyanate, propane diisocyanate, butane diisocyanate, pentane 20 ~ diisoc~anate, hexane diisocyanate, heptane diisocyanate, octane diisocyanate, nonane diisocyanate, decane diisocyanate, etc.;
isophorone diisocyanate, etc.
Similarly, the polyol compounds which can be :` :
,: , . . ~ - ................. . .
, 7~33~
used for the production of the urethane oligomer or ~he polyurethane reisin may include, for exarnple, glycol~
such as ethylene ylyaol, 1,2-propylene glyaol, 1~3-propylene ylygol, polypropylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, 2,2 dimethyl-1,3-propanediol, diethylene glycol, polyethylene glycol, 1,5-pentamethylene glycol, 1,6-hexamethylene glycol, cyclohexane-1,4-diol, cyclohexane-1,4-'dimethanol, polytetramethylene glycol, etc.; polyester polyols obtained by polycondensation of one or a mixture of the glycols with a dibasic acid such as succinic acid, maleic acid, adipic acid, glutaric a'cid, '-pimelic acid, suberic acid, azelaic acid,~sebacic acid, phthalic acid, isophthalic acid, terephthalic acid9 hexahydrophtha1ic acid, hexahydroisophthalic acid, etc. '' or an ester or~halide of the dibasic acid; and, further, polycaprolactone polyols obtained by ring-opening addition polymerization of a lactone such as ~-caprolactone in the presence of a glycol or the like. The polyol co~pound to be used for formation of the urethane oligomer:or for direct formation~of the urethans preferably has:a molecular weight of 100 to 2,000,: particularly 500 to 1,000.
The compound having a ~meth)acrylic~double bond and an isocyanate-reactive :group in the molecule thereof, for use in converti~g both terminals of the main chain into acryloyl, .
- ,: . ~ . .., . : . . .
,~ . . . . . .
~ ~ ~ 7 ~ ~9 - 18 - ~5702-307 may bel for example, a 2~hydroxyalkyl acrylate or methacryla~e, particularly such acrylate or me~hacrylate having 2 to 12 carbon atoms in the alkyl moiety which may be substituted by, fox ~x-ample, chloro, acryloxy, methacryloxy, allyloxy, cinnarnyl, phenoYy, o-chlorophenoxyl p-chlorophenoxy, 2,4-dic~lorophenoxy, ac~-~o~, propionyloxy, chloroacetoxy, dichloroaceto~y, t~i~hloroacetox~, benzoxy, o-chlorobenzoxy, 2,4-d:Lchlorob~2Oxy, 3,4-dlchlorobenzoxy, etc.
Particularly preferred are those having a formula:
.. ,5 HO - CH - CH2 - 0 -C - C = CH2 in which R6 is (1) hydrogenl ~2) an alkyl having 1 to 10 carbon atoms or (3) -CH2-R7, where R7 is a substituent such a~ halogen, acryloxy, methacryloxy, allyloxy, cinnamyl, phenoxy (in which the phenyl radical may be further substituted by chloro), lower alkanoyloxy (e.g., acetoxy, propionoxy, etc.), lower chlorinated alkanoyloxy (e.g., chloroacetoxy, dichloroacetoxy, trichloro-aceto~y, etc.), benzoxy (in which the phenyl radical may further be substituted by chloro), phenoxyacetoxy:(in which the phenyl radical may ~urther be substituted by chloro), crotonoxy, cinnamy- -loxy etc. Specifi~ examples include 2-hydroxyethyl acrylate or methacrylate, 2-hydroxypropyl acrylate or methacrylate, 2-hydroxy-butyl acrylate~or methacrylate, 2-hydroxyoctyl acrylate or methacrylate, 2-hydroxydodecyl acrylate or me.thac~ylate, 2-hydroxy-3 chloropropyl acrylate or methacrylate, 2-hydxoxy-3-acryloxypropyl ac:rylate or methacrylate, ~-hydroxy-3-meth-: :
;,,~
~ . . - . .: , , :~ . ' : ; ' :, - : . .
, . , , ,; . , - ` ' . . .: ~ , . . . .. . . , ... . ,~ . :
~ ~37~
- 18a - 65702-307 acryloxypropyl acrylate or methacxylate, Z-hydroxy-3-allyloxy-propyl acrylate or mPthacrylate, 2-hydroxy-3-cinn~mylprop~l acrylate or methacrylate, 2-hydroxy-3-phenoxypropyl acrylake or methacrylate, 2-hydroxy-3-(o-chloxophenoxy)propyl acrylate o~
methacrylate, 2-h~drox~~3-~p-c~lorophenoxy)propy~ acrylat~ or methacrylate, 2-hydroxy-3-(2,4-diahlorophenoxy)propyl acrylate or methacrylate, 2-hydroxy-3-acetoxypropyl acrylate or mekhacryl-ate, 2-hydroxy-3-propion~xypropyl acrylate or methacrylate, 2-hydroxy-3-chloroacetoxypropyl acrylate or methacrylate, 2-hydroxy-3-dichloroacetoxypropyl acrylate or methacrylate, 2-hydroxy-3-trichloroacetoxypropyl acrylate or methacrylate, 2-hydroxy-3-benzoxypropyl acrylate or-methacrylate, 2-hydroxy-3-(o-chlorobenzoxy)propyl acrylate or methacrylate, 2-hydroxy-3-(p-chlorobenzoxy)propyl acrylate or methacrylate, 2-hydroxy-3-(2,4-dichlorohenzoxy)~propyl acrylate or methacrylate, 2- hydroxy-3-(3,4--; , ; , - . ... . . . .
~ 2~
dichlorobenzoxy)propyl acrylate or methacrylate, 2-hydroxy-3-(2,4,6-trichlorophenoxy)propyl acrylate or m~thac~ylat~, 2-hydroxy-3-(2~4~5-trichlorophenoxy)propyl acrylate or methacrylate, 2-hydroxy-3-~o- ch lorophenoxyacekoxy)propyl acrylate or ~ethacrylate, 2-hydroxy-3 phenoxyacetoxypropyl acrylate or methacrylate, ~-hydroxy-3-(p-chlorophenoxy~
acetoxy)propyl acrylate or methacrylate, 2-hydroxy-3-(2,4,5-trichlorophenoxyacetoxy)propyl acrylate or methacrylate, 2-hydroxy-3-crotonoxypropyl acrylate or methacrylate, 2-hydroxy-3-cinnamyloxypropyl acrylate or -methacrylate, 3-acryloxy-2 hydroxypropyl acrylate or methacrylate, 3-allyoxy-2-hydroxypropyl acrylate or methacrylate,~3-chloro-2-hydroxypropyl acrylate or methacrylate, 3-chloroxy-2-hydroxypropyl acrylate or methacryalte, or other similar acrylic or methacrylic acid ester; or a compound having active hydrogen capable of reacting with~an isocyanate group and containing an acrylic double bond, such as:acrylamide, methacrylamide, N-methylolacrylamide, etc.
To the reaction for forming the urethane oligomer and the reaction for forming the polyurethane,~oridnary conditions for polyurethane reaction can be applied.
For instance, a~method comprisin~ sufficiently mixing the reactants, pouring the reaction mixture on a flat :
plate or into a VAt to heat the reaction mixture, khen cooling the heated produck and cru~hing the cooled product, a solution r~action method com~risiny brlnglng the reactants into reaction i.n an organic solvent consisting one or a mixture of dimethylformamide, toluene, xylene, benzene, dioxane, tetrahydrofuran, cyclohexane, methyl ethyl ketone, methyl isobutyl ketone, e~c.j or other production method can be adopted. In order to reduce the reaction temperature or to shorten the reaction time, a reaction catalyst may be added. Examples of the reaction catalyst include amine compounds such as triethylenediamine, tetramethylethylenediamine, tetramethylhexanediamine, etc., salts thereof r organometallic compounds such as~dibutyltin ~ilauxale, tin octylate, lead octylate, manganese octylate, etc., mixtures thereof, etc. Further, antioxidant, UV absorber, hydrolysis preventive or the like may be mixed into the reaction mixture, either singly or in combination, for the purpose of enhancing the stability of the polyurethane~resin obtained.
Moreover, in view of the use of the crosslinkable compounds as the reactants, a polymerization inhibitor such as hydroquinone may be used.
In the magnetic recording medium according to :
. . . . .
33~
the present invention, the magnetic layer comprises a binder which, in turn, comprises the crosslinked pxoduat oP the polyurethane resin as speal~led above. As the binder, there may be jolntly use~ any o various reslrls which are ordinarily used as a binder, ~or instance, thermoplastic polyurethane resins; cellulose derivatives such as nitrocellulose, cellulose acetate, cellulose acetate butyrate, etc.; vinyl chloride/vinyl acetate resins such as vinyl chloride/vinyl acetate copolymer, vinyl chloride/
vinyl acetate/vinyl alcohol copolymer, vinyl chloride/vinyl acetate/male~c acid copolymer, etc.; vlnylidene chloride resins such as vinyl~idene chloride/vinyl chloride copolymer, vinylidene chloride/acrylonitrlle copolymer, etc.; polyester resins such as a~kyd resin, linear polyester, etc.; acrylic resins such as (meth)acrylic acid/acrylonitrile copolymer,~ methyl (meth)acrylate/acrylo-nitrile copolymer, etc.; acetal resins such as polyvinyl acetal, polyvinyl butyral, etc.;~phenoxy resinsj epoxy resins,~polyamide resins, butadiene/acrylonitrile copolymers, styrene/butadiene copolymers, etc., either singly or in combination.
Furthermore, convention;al r~adiation-curable compounds, such as trimethylolpropane triacrylate, may al50 be used jointly.
:
:, , 7~33~j , . .
~- When the other components ~an the crosslinked pxoduct of -the polyure-thane accord:Lng to the present invention are used together wlth khe cro~sllnk~d produc~ a~
the binder, the composition o~ the binder is preEerably so selected that the amount of the cross-linked product of the polyurethane resin is at least 5b% by weight based on the total amount of the binder.
The powders of ferromagnetic substances which can be used in the present invention include, for example, powders of ~-Fe2O3, mixed crystals of y-Fe2O3 and Fe3O4, Co-modified iron oxide, CrO2, iron, etc. Also, any fine powder of an iron-based alloy can be preferably used.
.
The particles of the fine ferromagnetic powder may have any shape, such as acicular, plate-like, spherical, etc.
The magnetic layer~ of the magnetic recording meidum according to the present invention may comprise additives such~as dispersant, lubricant, antistatic agent, abrasive, etc~., in addition to the binder and the ferromagnetic powder.
The crosslinklng of the urethane oligomer and the polyurethane resi~ according to the present invention is preferably carried out by uslng radlations, particularly, electron beams. The dosage of the electron beams is generally 0.5 to 20 Mrad. ~
~ .
~ ' - . , . :., ~ . . - :`
, ~2~ 783~
_ 23 -The non-magnetic support ~or ~lse in producing the magnetic recording medium according ko the pre~ent invention may be ~ormed o, or examp~e, a polyester such as polyethylene terephthalate; a polyolefirl such as polyethylene, polypropylene~ etc.; a cellulose derivative such as cellulose triacetate, cellulose diacetate, etc.;
a polycarbonate; polyvinyl chloride; a polyimide; a plastic such as aromatic polyamidei a metal such as Al, Cu, etc.; a paperj or the like. The form of the non-magnetic support may be any of film, tape, sheet, disk, card, drum, etc. The surface of the support may be treated with corona dlscharge, radiations, UV rays or the like, or may be precoated with an appropriate resin.
EXAMPLES
The present invention will now be explained more in deetail below while referring to nonlimitative Synthetic Examples and Examples.
In the following examples, the term "parts"
means "parts by;weight".
<Synthetic Example 1 of ~9~L~ah~ne ~ A>
A reaction vessel equipped with a thermometer, ~ stirrer and a reflux condenser was charged with 200 parts : : .
: ; :
:
~.X~ 33 of methyl ethyl ketone, 79 parts of the dlhydroxyl compound having the followlng ~ormula (I~I), R0 - CHz- Cllz ~ N- Cll~- Cll ~ - 011 I
~=~ O
.
NN -:~C~31 ~I~H ( m ) ~o - c o 1 11 , 0 - CH2- CHz- 0 - C- CH= CH2 ~ 70.5 parts of tolylene:diisocyanate (a ao:20 mixture of .~ 2,4-tolylene~di~isocyanate and 2~,6-tolylene diisocyanate) : and 0.2 part of~hydroquinone, and the resultant mixture : was~:stirred at 70C for 4 hours.: Thenj 202 parts of polybutylene:adipate having a::molecular weight of 500 (with : hydroxyl~group at both terminals of the molecule : thereo ) : : and 400 parts of methyl ethyl ketone : were~added to~the reaction mixture,~and the resultant i ~ : : ~ :
~ axmixture was:~stirred at 75C for 6:hours to obtain a :~ urethane oligomer.: : ~
Further,~800 parts~of:polybutylene e~ipa+~ h~mg a molecular weight of l,OOO (with~ hydroxyl group at both terminals of ~he molecule thereof), 108 parts of 1,4-: butanediol, 416:~parts of neopentyl glycoI,~l,S00 parts : ~ :
, : :
:,: ~ : : :
: :
7~
of diphenylmethane-4,4'-diisocyanate, 0.3 part of dibutyltin dilaurate and 3,000 parts of methyl ethyl keto~e were placed into the reaction vessel, and the re~ultank ~ixtl1re was stlrred at 80C Eor 10 hours to obtain a polyurethane resin (PV-l).
The average molecular weight of the thus obtained resin determined by gel permeation chromatography was 16,000O
~ -:
<Synthetic Example 2 of Polyurethane Resin>
The same reaction vessel as that used in Synthetic : Example 1 was charged with 400 parts of methyl ethyl ketone, 198 parts of the dihyroxyl compound having the general ;: : formula (III) used in Synthetic Example 1, 224 parts of ~ isophorone dlisocyanate and 0.2 part of hydroquinone, and :~ the resultant mixture was stirred at 70C for 6 hours. :
:~ Then, 500 parts of polytetramethylene glycol having a molecular weight of 500 and 800 parts of methyl ethyl ketone were~added to the reaction system, and the resultant ~ admixture was stirred at 75C for 8 hours.to:obtain a urethane oligomer. ~ .
Furthsr, 500 parts of polybutylene adipate :-having a molecular weight of l,000 (with hydroxyl. group : at both terminals of the molecule thereof) r 260 parts of ::
;~
::: :
~ , , , ,: : , , .
~ ~37~3~;
neopentyl glycol, 153 parts of 1,6-hexanedlol, 1,225 parts of diphenylmethane-4,4'-diisocyana~e~ 0.3 part of dibutyltin dilaurate and 1~800 parts o~ methyl ethyl ketone were added to the reactlon ves~el, and the rssultant mlxture was stirred at 80C for 10 hours to obtaiTI a polyurethane resin (PU-2).
The average molecular weight of the thus obtained resin determined by gel permeation chromatography was 30,300.
<Synthetic Example 3 of Polyurethane Resin>
A polyurethane resin was obtained in the same manner as in Synthetic Example 1.
Then, to 800 parts of the polyurethane resin (which had an average molecular weight of 16,000 as determined by gel permeation chromatography), 26 parts of diphenylmethane-4,4'-diisocyanate was added, and the resultant mixture was stirred at 80C for 7 hours to form a polyurethane resin having isocyanate group at both terminaIs of the main chain thereof. Further, 12 parts of 2-hydroxyethyl acrylate was added to the reaction vessel, and the resultant mixture was stirred at 80C for 8 hours to obtain a polyurethane resin tPU-3) having acryloyl group at both terminals of the main chain thereof~
:
- . , . , . . - . . .
33~
<Synthetic Example 4 of Polyurethane Resln>
A polyurethane resin was obtained in the same manner as in Synkhetic Example 2.
'rhen, to 1,515 part~ o~ the thus obtained polyurethane resin (which had a molecular welght of 30,300 as determined by gel permeation chromatography), 13 parts of 2-hydroxyethyl methacryalte was added, and the resultant mixture was stirred at 80C for 8 hours to obtain a polyurethane resin (PU-4) having methacryloyl group at both terminals of the main chain thereof.
<Synthetic Example 5 of Polyurethane Resin>
In the same manner~as in Synthetic Example 1 except that the dihydorxyl compound having the formula (III) used in Synthetic Example 1 was replaced by 88.6 parts of the dihydroxyl compound having the following formula (IV), H0 ~ Cl12-~C}Iz - N- CH 2 - CH 2 - 0H
C= O ,' : NH
CHz Cll~
X
C H 3 7~ ~
C H 3 : N
O = C O
0~ CH2--CH2--O--C--CH--CHz :~
, , - . ` :. .
~ ~37~3~i a polyurethane resin (PU-5) was obtained.
The average molecular weight of the thu~
obtained resin determined by gel permeation chromatography was 15,700.
<Synthetic Example 6 of_P~y~rethane Resin> .
A reaction vessel equipped with a thermometer, -a stirrer, a reflux-type condenser tube and a nitrogen gas inlet tube was charged with 270 parts of methyl ethyl ketone, 270 parts of cyclohexane, 160 parts of polybutylene adipate diol (having an average molecular weight of 1~000 as determined by terminal group analysis), 18 parts of 1,4-butylene glycol, 52 parts of 2,2'-dimethyl-1,3-propanediol, 39.5 parts of the dihydorxyl compound having the formula (III) used in Synthetic Example 1, 233.5 parts of diphenylmethane'4,4'-diisocyanate, 0.3 part of dibutyltin dilaurate as catalyst and 0.2 part o~ hydroquinone as polymerization inhibitor, and the resultant mixture was stirred at 80C for 10 hours to obtain a polyurethane resin~
Then, 14 parts of diphenylmethane-4,4'-diisocyana~e was further added to the reaction system, and the resultant mixture was stirred at 80C for 5 hours. Thereafter, 6.5 :
parts of 2-hydroxyethyl acrylate was added to the reaction '' system, and the resultant admixture was stirred st 80C for :. :
,-:
-.
.
5 hours to obtain a polyurethane resin (PU-6) having acryloyl group at both terminals o~ the main chain thereof.
The molecualr weight of the thus obtained resin determined by gel permeation chromatography was 19,900.
EXAMPLES 1 to 6:
Each of the compositions A to F shown in Table 1 was kneaded in a ball mill for 24 hours to obtain respective magnetic paints.
Then, each of the magnetic paints was applied to a 70-~m thick polyethylene terephthalate film so that the thickness of the coating after dried was 2 ~m,and the resultant coatings were irradiated with electron beams with a dosage of 5 Mrad.
Each of the thus obtained films was cut to form a floppy disk 5.25 inches in diameter, and the durability of each floppy disk was evaluated by fittlng the floppy disk into a floppy disk drive and measuring the period of time required for the reproduction output to be lowered to 50% of the initial level, at 20C and at 40C. The results are shown in Table 2.
- , . . . .
: ' , ~ . ' ,. '. ',,: ' ' .' ~ ' 7~33 Table 1 _ Paint compo- A B C D E F
~ents of paint~~~
_ P U 1 - ~ 45 1 30 _ _ _ 3 ~ I 1 40 PU, 6 . - . . . . 40 .
. VAGHI) 15 . 10 . 5 TM P TA 2~ 5 5 10 _ 10 S
CO - r - Fe~O~ ~ 100~100 100 100 100 100 Carbon black 3 3 3 3 3 3 h ¦ AbraSlve3 3 . 3 3 3 3 . Lubricant8 8 8 8 8 8 : S Dispersant2 2 2 2 2 2 ~ Methyl ethyl k0k~300300300300 300 300 Notes: 1) vinyl chloride/vinyl acetate copolymer, produced by Union Carb1de Corporation, USA
2) tri;methylolpropane triacrylate 3) Co-coated y-Fe203 ;:
.
,:
.
Table 2 ' l'' Examples ¦ Magnetic Durabllity u Ider drive (hr) , . . palnt at 20C at 40C
Example 1 A loo or more 100 or more .Example 2 B : " ,~
. Example 3 ~ D: ~ ~
Example 4 E .. ~ : :
Example 5 Example 6 F .. ..
_ . ._ ~.
::
<Synthetic Example (1) of Urethane Oligomer>
A reaction vessel equlpped with a thermometer, :
a stirrer and a reflux condenser was charged with 400 parts of methyl ethyl ketone, 198 parts of the d~hydroxyl compound having the following Pormula (III) t HO - CHz--CH2--N--CHz--CHz--OH :
CY O
NH
I
o--~ : O ~ ' 11 ,, O--CHz--GHz--O--C--CH=CHs ,, . . ~: ,'' . ", ,~
. .
.. . . . . .
:... .
. .
37~
174 parts of tolylene diisocyanate (a 80:20 mixture o-f 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate) and 0.2 part of hydroquinone, and the resultant mixture was stirred at 70C for 4 hours. Then, 1,000 parts of polybutylene adipate having a molecular weight of 1,000 -~
twith hydroxyl group at~both terminals of the molecule thereof) and 800 parts of methyl ethy1 ketone were added to the reaction system, and the resultant mixture was stirred at 75C for 6 hours to obtain a urethane oligomer.
.
cSynthetic Example (2) of Urethane Oligomer>
700 parts of the urethane oligomer having hydroxyl group at both terminals of the main chain thereof obtained in Synthetic Example (1) was transferred into another reaction vessel together with the reaction solvent, then 126 parts of diphenylmethane-4,4'-diisocyanate was added thereto, and the resultant mixture was stirred at 80~C for 8 hours. Thereafter, sa parts of 2-hydroxyethyl acrylate was added to the reaction system, and the resultant admixture was stirred at 80 QC for 8 hours to obtain a urethane oligomer having acrylocyl group at both terminals~of the main chain thereof.
.
.. ' . . . ' .: .
.; , . .
~ 37~
<Synthetic Example (3) of Urethane Oli~omer>
The same reaciton vessel as that usea in Synthetic Example (1) was chaxged with 350 parts of methyl ethyl ketone, 198 parts of the dihydorxyl compound having the general formula (III) used in Synthetic Example (1), 130.5 parts of tolylene diisocyanate used in Synthetic Exmaple (1) and 0.2 part of hydroquinone, and the resultant mixture was stirred at 80C for 8 hours~ Then, 250 parts -of ~-caprolactone glycol (molecular weight: 500) and 250 parts of methyl ethyl ketone were added to the reaction system, and the resultant admixture was stirred at 80C for 8 hours to obtain a urethane oligomer having hydroxyl group at both teFminals of the molecule thereof.
<Synthetic Example (4) of Urethane Oligomer~
300 parts of the urethane oligomer obtained in Synthetic Example (3) was transferred into another reaction vessel together w1th the reaction solvent, then 32.5 parts of 2-hydroxyethyl methacrylate was added thereto, and the resultant admixture was stirred at 80C for 8 hours to obtain a~urethane oligomer having mechacryloyl group at both terminals of the main chaln thereof.
..
7~3~;
EXAMPLES 7 to 10 and COMPARATIVE EX~MPLES 1 and 2:
Each of the compositions G to J shown in Table 3 was kneaded in a ball mill for 24 hours to obtain respective magnetic paints~ :
Then, each of the magnetic paints was applied to a 70-~m thick polyethylene terephthalate film so that the thickness of the coating after dried was 2 ~m, and the resultant coatings were i~radiated with electron beams with a dosage of 5 Mrad:~
Each of the thus obtained films was cut to form a floppy disk 5.25 inches in diameter, and the durability of ~he floppy disk was evaluated b~ fitting the floppy disk into a floppy disk drive and meas~ring-the period of time required for the repro~uction output...to be lowered to 50~ of the initial level~ at 20C and at 40C. The resuIts æe shown in Table 4.
By way of comparison, magnetic paints K and L ;
shown in Table 3 were prepared in the same manner as above.
Only the magnetic paint K was subjected, after 24-hour kneading, to kneading for 1 hour by adding thereto 10 parts trade ~ark of a curing agent (~e~uh}-hRme: COLONATE L, produced by Nlppon Polyurethane Kogyo K.K.~. Next, the thus prepared paint was applied to a 70-~m thick polyethylene terephthalate film so that the thickness of the coating . - - . . - , , :. .. .
_ 35 -after dried was 2 ~m, and was dried and aged. Then, the thus obtained film was cut to form a floppy dlsk 5.25 inches in diameter, and the durability of the floppy disk was evaluated by fitting the floppy disk into a floppy disk drive and measuring the period of time required for the reproduction output to be lowered to 50%
of the initial level, at 20C and at 40C.
On the other hand, the magnetic paint L was treated in the same manner as the magnetic paints G to J, thereby forming a floppy disk, and the durability of the thus obtained floppy disk was evaluated by fitting the floppy disk into a floppy disk drive and measuring the period of time required for the reproduction output to be lowered to 50% of the initial level. The results ;~
are shown in Table 4.
:
. .
.
~,, ,, ,, : , ' :, ~:, ' , . . .
, .
~3~
Table 3 _ Ex~e E~le E~ple Ee~le Co~xIa Co~xra-. 7 8 9 10 ~ive E~, tiV2e EX-_ .. _ _ _ _ . = etic p~nt G H I J K L
_~ . _ ._ . __ _ Synthetic Ex.~l~ 30 Synthetic Ex.(2~ ~ 35 . Synthetic Ex.(3) . 40 c Synthetic Ex.(4) : . 40 . V A G Ha) 5 10 ~5 ~ . 20 15 N - ~ 3 0 4 2~ 5 , 5 ~ ~
T M P ~ A~ 10 5 5 10 _ _ ....
- r - Fe~0~ 'j 100 1~ 100 100 100 100 3 Carbon black 3 : 3 3 3 3 3 ;~ Abrasive 3 3 3 3 . -3 3 :~ Lubricant 8 8 8 8 8 . 8 ~ Cyclohexane 150 150 150 150 150 150 : ~ Methyl et~y} k*~ne 100 100 100 100 100 100 Notes: 1) vinyl chloride/vinyl acetate copolymer,:produced : by Union Carbide Corporation, USA
2) thermoplastic polyurethane resin, produced by Nippon Polyurethane Kogyo K.K.
: 3) trimethylolpropane triacrylate ~ 4) Co-coated y-Fe2O
:
,: . ,, : . .
: ;
33~;
Table 4 . .
Examples and Magnetic D~iliky wx~rdrive (hr) Comparativ~ Example paint ~ at 20C at 40C
_ ~~
Example 7 G 100 or more 100 or more .
Example 8 H .. "
Example 9 I "
Example 10 J _ _ _ ll Comparative Ex. 1 K 10 or less 10 or less Comparative Ed. 2 L ll "
., ---- __ : , ; ' Examples concerning the dihydorxyl compound will now be descrlbed below. .
EXAMPLE 11: ~
A first-stage reaction was carried out by charging a reaction vessel having a stirrer, a thermometer and a reflux condenser attached thereto with 100 parts of 2,4-tolylene dilsocyanate, 66.7 parts of 2-hydroxyethyl acrylate and 0.1 part of hydroquinone, and stirring the ;
resultant mixture at 40F for 1 hour and then at 60C for 3 hours.
~' :
~ ~ -:
' ' " ' ':' - , .
.. : . ..
, ~- : .: . : , : ~ . , Next, a second-stage reaction was carried out as follows. To the reaction vessel was added 667 parts of methyl ethyl ketone, the reaction system was then cooled to 5C, and 60.3 parts of diethanolamine was added dropwise to the reaction system at that temperature over 1 hour.
After the dropwise addition, the resultant admixture was stirred at 20C for 6 hours, and then methyl ethyl ketone was distilled off to obtain a white powder.
The compound obtained on the first-stage reaction was subjected to detexmination of isocyanate concentration (by a ~i-n-butylamine/hydrochloric acid titration method), and the concentration was found to be about 1/2 times the value before the reaction. The residual isocyanate in the compound was reacted with ethanol, and after capping, the compound was analyzed by li~uid chromatography (column: Hibar Lechrosorb Si-60;
solvent: 0.5% methanol-containing dichloromethane). The analytical result showed that the compound was a compound having the following formula (IV).
CH~
~J
HN
oc~ O
O--C H z--C H 2--O--C--C H--C H 2 ~I racle-fnRrk '', . ' '' . ` ' , ~, - : ~
. -"
,' ~ . .
',' : ' ,' ' ,' ' ' ~ ' ' : ' , :
. .
783~;
The shite powder obtained upon the second-stage reaction was subjected to potentiometric titration using perchloric acid, whereby it was confirmed that amino groups had disappeared. It was also confirmed by the above mentioned di-n-butylamine/hydrochloric acid titration method that isocyanate groups had di~appered.
. Furtherj it was confirmed by NMR that the white powder finally obtained was a compound having the following formula (V)O
1 H-NMR ( solvent DMSO-d ) ~ : internal standard TSP
2.1 ~2.3 . Ar--CH3 ~) 3.2 ~4.3 -CH2-- . Q ~ ~;) (~) N
6 . 0 ~ 6 . 5 - C = C 0 (: 3 O
H H
7. 0 ~8. 4 Ar--H ~ ~3 HO--CH ~--CH z--N--CH 2--CNz--OH
O = C
~C~H (v) ~) N/~H (~) :
0 O--C~ O H (5~) I (~i) (~) 11 (~) I
o-- CNz--CH2--O--C~ CH= C
H ( ~) . , . . ., ~ ..
, , : ,: -:. :, . .. . , :
; ~ - -- ~ :
Then, a reaction vessel equipped with a stirrer, a thermometer and a reflux condenser was charged with 60.7 parts of the compound of the formula (V), 100 parts of polybutylene adipate (number average molecular weight:
1,000), 16 parts of 2,2-dimethyl-1,3-propanediol, 8 parts of 1,4-butylene glycol, 154 parts of diphenylmethane-4,4'-diisocyanate and 390 parts of methyl ethyl ketone, and .:
the resultant mixture was stirred at 80C for 12 hours, to obtain a viscous liquid. When methyl ethyl ketone was distilled o~f from the viscous liquid, a polyurethane ~ .
resin was obtained as a single mass. :
.:EXAMPLE 12:
A shite powder was obtained in the :same manner as in Example 11 except that 92.5 parts of dibutanolamine was used in place of the diethanolamine used in Example 11. The white powder thus obtained was analyzed in the .
same manner as in Example 11, and was found to be a compound , having the following formula (VI).
HO - CH2 - CH2 - CH2 - CHz - N- CH2 - CH2- CH~ - CNz- OH
'' C--:O
NH ~-C ~ ~ (VI) : . N
I
0=~ 0 Il O - CH2 - CHz- O - C- CH- CHz "
: . ,, . .:, - . .,, : .. .
Then, 69.3 parts of the thus obtained compound of formula (VI) was subjected to a reaction in the same manner as in Example ll, to obtain a polyurethane resin.
.
.
When the polyurethane resin haviny -OH ~k both terminals oE the maln chaLn thereo~ L~s used, the polyurethane resin ls r~acted wlth a d:L-i~ocya~ate compound in a molar ratio o~ about 1:2, thereby converting both terminals of the main chain into -NCO, and then the objective polyurethane resin can be obtained in the same manner as above. Alternatively, the terminals of the main chain may be converted into (meth)acryloyl by reaction with (meth)acrylic acid or a lower alkyl ester thereof.
While a method o~ preparing the objective polyurethane resin through a urethane oligomer (this term is synonymous with "urethane prepolymer") has been described above, a method based on direct urethane formation, as follows, may also be applied.
(2) The dihydroxyl compound having the above formula (II) or a mixture thereof with other polyol component is reacted directly with a di-isocyanate compound, whereby a polyurethane resin having -OH or -NCO~at both terminals of the main chain thereof can be obtained. In this case, the molar ratio of ON/NCO of the polyol and the di-isocyanate is in the range of l/0085 to 1/1.15, preferably loO/0~95 to l.O/1.05.
:~ `
: .
, . , ., . : -, ~ ~37~33~i ~ 6570Z-307 Conversion of both terminals of the main chain into ,5 - 0 C - C = CH
O
can be carried out by the above-mentioned method~
The dihyd~oxy:l. comE~ound having the above-mention~d general formula (II) ~or use as a starting material for khe ure-thane resin according to the pxesent invention is a novel compound, ~ and can basically be produced by the following steps.
;. (a) First, a diisocyanate compound of the formula:
~ OCN - R3 - NCO and a hydroxyalkyl (meth)acry~ate compound of the ;; " ,5 ~ lQ formula: HO - R4 - 0 - C - C = ~H2 are mixed with each other and -. stirred to produce an intermediate of the formula:
OCN - R3 - NH - CO - O - R4 - O - C - C = CH2. In this case, it is preferable to add a polymerization inhibitor such as hydro-: quinone and to;set khe temperature to 70C or lower. .
: : (b) Thenr an inert organic solvent such as methyl ethyl ketone is added to the reaction system, further a dialkanolamine of the formula:; HO - Rl - NH - R2 ~ OH is added to the system, and the resultant mixture is stirred. In this case it is pre-ferable to add the dialkanolamine dropwise to the system and to 20 - - set the temperature of the system to 10C or lower.
The reaction time is not particularly limitedt , 33~
and depends on the reactant compounds. TO achieve a certain degree o~ y.L~ld~ howeve~ h~ reac tibn ~im~ is ordinarily 2 to'5 hours lh ~a), and 3 to 10 hours in (b~
Referring to the starting compounds for use in the production o~ the polymerizable dihydroxyl compound, the di-isocyanate compound may be, for example, an aromatic di-isocyanate such as m-phenylene diisocyanate, p-phenylene diisocyanate, l-chloro-2,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthtylene dlisocyanate, diphenylmethane-4,4'-dilsocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, etc.; an aliphatic dl-isocyanate such as ethane diisocyanate, propane diisocyanate, butane diisocyanate, pentane dilsocyanate, hexane diisocyanate, heptane diisocyanate, ;~
octane diisocyanate, nonane diisocyanate, decane dlisocyanate, etc.; isophorone dlisocyanate, or the like.
Among others, 2,4-tolylene dlisocyanate and isophorone diisocyanate, in~which the two isocyanate groups differ in reactivity, are preferred.
This is because it is advantageous that the hydroxyalkyl (meth)acrylate reacts mainly wlth one of the two isocyanate groups of the di-isocyanate compound in the flrst stage reaction of the two compounds, for a higher :~ ~
, .~
~ ~ : : . , : . , :
.: : . :
~ ~3'7~
- 16 ~ 65702-307 yield of the final objective product.
The hydroxylalkyl (meth)acrylate has preferably Z to 12, more preferably 2 to 5 carbon atoms in the alkyl moiety and may be, ~or example, hydro~yethyl methacrylate, hydroxypxopyl (meth)acrylate, hydro~ybu~yl ~mekh)ac~yl~-te, hyd~oxyh~Yyl (meth) acrylate or the like. The dialkanolamine has pre~erably 2 to 8, more preferably 2 or 3 carbon atoms in each o~ the alkanol moiety and may be, ~or example, diethanolamine, dipropanalamine, di-butanolamine, ~hexanolamine or the like.
The diisocyanate compounds which can be used for preparation of the polyurethane from the dihydroxyl compound hav-ing the general formula (II), either through preparation of a urethane oligomer or directly, may include, for example, aromatic - diisocyanate such as m-phenylene diisocyanate, p-phenylene diiso-cyanate, l-chloro-2,4-phenylene diisocyanate, 2,4-tolylene diiso-cyanate~ 2,6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyl-4,4'-biphenylene ~ diisocyanate, etc.; aliphatic diisocyanates such as ethane diiso-;~ cyanate, propane diisocyanate, butane diisocyanate, pentane 20 ~ diisoc~anate, hexane diisocyanate, heptane diisocyanate, octane diisocyanate, nonane diisocyanate, decane diisocyanate, etc.;
isophorone diisocyanate, etc.
Similarly, the polyol compounds which can be :` :
,: , . . ~ - ................. . .
, 7~33~
used for the production of the urethane oligomer or ~he polyurethane reisin may include, for exarnple, glycol~
such as ethylene ylyaol, 1,2-propylene glyaol, 1~3-propylene ylygol, polypropylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, 2,2 dimethyl-1,3-propanediol, diethylene glycol, polyethylene glycol, 1,5-pentamethylene glycol, 1,6-hexamethylene glycol, cyclohexane-1,4-diol, cyclohexane-1,4-'dimethanol, polytetramethylene glycol, etc.; polyester polyols obtained by polycondensation of one or a mixture of the glycols with a dibasic acid such as succinic acid, maleic acid, adipic acid, glutaric a'cid, '-pimelic acid, suberic acid, azelaic acid,~sebacic acid, phthalic acid, isophthalic acid, terephthalic acid9 hexahydrophtha1ic acid, hexahydroisophthalic acid, etc. '' or an ester or~halide of the dibasic acid; and, further, polycaprolactone polyols obtained by ring-opening addition polymerization of a lactone such as ~-caprolactone in the presence of a glycol or the like. The polyol co~pound to be used for formation of the urethane oligomer:or for direct formation~of the urethans preferably has:a molecular weight of 100 to 2,000,: particularly 500 to 1,000.
The compound having a ~meth)acrylic~double bond and an isocyanate-reactive :group in the molecule thereof, for use in converti~g both terminals of the main chain into acryloyl, .
- ,: . ~ . .., . : . . .
,~ . . . . . .
~ ~ ~ 7 ~ ~9 - 18 - ~5702-307 may bel for example, a 2~hydroxyalkyl acrylate or methacryla~e, particularly such acrylate or me~hacrylate having 2 to 12 carbon atoms in the alkyl moiety which may be substituted by, fox ~x-ample, chloro, acryloxy, methacryloxy, allyloxy, cinnarnyl, phenoYy, o-chlorophenoxyl p-chlorophenoxy, 2,4-dic~lorophenoxy, ac~-~o~, propionyloxy, chloroacetoxy, dichloroaceto~y, t~i~hloroacetox~, benzoxy, o-chlorobenzoxy, 2,4-d:Lchlorob~2Oxy, 3,4-dlchlorobenzoxy, etc.
Particularly preferred are those having a formula:
.. ,5 HO - CH - CH2 - 0 -C - C = CH2 in which R6 is (1) hydrogenl ~2) an alkyl having 1 to 10 carbon atoms or (3) -CH2-R7, where R7 is a substituent such a~ halogen, acryloxy, methacryloxy, allyloxy, cinnamyl, phenoxy (in which the phenyl radical may be further substituted by chloro), lower alkanoyloxy (e.g., acetoxy, propionoxy, etc.), lower chlorinated alkanoyloxy (e.g., chloroacetoxy, dichloroacetoxy, trichloro-aceto~y, etc.), benzoxy (in which the phenyl radical may further be substituted by chloro), phenoxyacetoxy:(in which the phenyl radical may ~urther be substituted by chloro), crotonoxy, cinnamy- -loxy etc. Specifi~ examples include 2-hydroxyethyl acrylate or methacrylate, 2-hydroxypropyl acrylate or methacrylate, 2-hydroxy-butyl acrylate~or methacrylate, 2-hydroxyoctyl acrylate or methacrylate, 2-hydroxydodecyl acrylate or me.thac~ylate, 2-hydroxy-3 chloropropyl acrylate or methacrylate, 2-hydxoxy-3-acryloxypropyl ac:rylate or methacrylate, ~-hydroxy-3-meth-: :
;,,~
~ . . - . .: , , :~ . ' : ; ' :, - : . .
, . , , ,; . , - ` ' . . .: ~ , . . . .. . . , ... . ,~ . :
~ ~37~
- 18a - 65702-307 acryloxypropyl acrylate or methacxylate, Z-hydroxy-3-allyloxy-propyl acrylate or mPthacrylate, 2-hydroxy-3-cinn~mylprop~l acrylate or methacrylate, 2-hydroxy-3-phenoxypropyl acrylake or methacrylate, 2-hydroxy-3-(o-chloxophenoxy)propyl acrylate o~
methacrylate, 2-h~drox~~3-~p-c~lorophenoxy)propy~ acrylat~ or methacrylate, 2-hydroxy-3-(2,4-diahlorophenoxy)propyl acrylate or methacrylate, 2-hydroxy-3-acetoxypropyl acrylate or mekhacryl-ate, 2-hydroxy-3-propion~xypropyl acrylate or methacrylate, 2-hydroxy-3-chloroacetoxypropyl acrylate or methacrylate, 2-hydroxy-3-dichloroacetoxypropyl acrylate or methacrylate, 2-hydroxy-3-trichloroacetoxypropyl acrylate or methacrylate, 2-hydroxy-3-benzoxypropyl acrylate or-methacrylate, 2-hydroxy-3-(o-chlorobenzoxy)propyl acrylate or methacrylate, 2-hydroxy-3-(p-chlorobenzoxy)propyl acrylate or methacrylate, 2-hydroxy-3-(2,4-dichlorohenzoxy)~propyl acrylate or methacrylate, 2- hydroxy-3-(3,4--; , ; , - . ... . . . .
~ 2~
dichlorobenzoxy)propyl acrylate or methacrylate, 2-hydroxy-3-(2,4,6-trichlorophenoxy)propyl acrylate or m~thac~ylat~, 2-hydroxy-3-(2~4~5-trichlorophenoxy)propyl acrylate or methacrylate, 2-hydroxy-3-~o- ch lorophenoxyacekoxy)propyl acrylate or ~ethacrylate, 2-hydroxy-3 phenoxyacetoxypropyl acrylate or methacrylate, ~-hydroxy-3-(p-chlorophenoxy~
acetoxy)propyl acrylate or methacrylate, 2-hydroxy-3-(2,4,5-trichlorophenoxyacetoxy)propyl acrylate or methacrylate, 2-hydroxy-3-crotonoxypropyl acrylate or methacrylate, 2-hydroxy-3-cinnamyloxypropyl acrylate or -methacrylate, 3-acryloxy-2 hydroxypropyl acrylate or methacrylate, 3-allyoxy-2-hydroxypropyl acrylate or methacrylate,~3-chloro-2-hydroxypropyl acrylate or methacrylate, 3-chloroxy-2-hydroxypropyl acrylate or methacryalte, or other similar acrylic or methacrylic acid ester; or a compound having active hydrogen capable of reacting with~an isocyanate group and containing an acrylic double bond, such as:acrylamide, methacrylamide, N-methylolacrylamide, etc.
To the reaction for forming the urethane oligomer and the reaction for forming the polyurethane,~oridnary conditions for polyurethane reaction can be applied.
For instance, a~method comprisin~ sufficiently mixing the reactants, pouring the reaction mixture on a flat :
plate or into a VAt to heat the reaction mixture, khen cooling the heated produck and cru~hing the cooled product, a solution r~action method com~risiny brlnglng the reactants into reaction i.n an organic solvent consisting one or a mixture of dimethylformamide, toluene, xylene, benzene, dioxane, tetrahydrofuran, cyclohexane, methyl ethyl ketone, methyl isobutyl ketone, e~c.j or other production method can be adopted. In order to reduce the reaction temperature or to shorten the reaction time, a reaction catalyst may be added. Examples of the reaction catalyst include amine compounds such as triethylenediamine, tetramethylethylenediamine, tetramethylhexanediamine, etc., salts thereof r organometallic compounds such as~dibutyltin ~ilauxale, tin octylate, lead octylate, manganese octylate, etc., mixtures thereof, etc. Further, antioxidant, UV absorber, hydrolysis preventive or the like may be mixed into the reaction mixture, either singly or in combination, for the purpose of enhancing the stability of the polyurethane~resin obtained.
Moreover, in view of the use of the crosslinkable compounds as the reactants, a polymerization inhibitor such as hydroquinone may be used.
In the magnetic recording medium according to :
. . . . .
33~
the present invention, the magnetic layer comprises a binder which, in turn, comprises the crosslinked pxoduat oP the polyurethane resin as speal~led above. As the binder, there may be jolntly use~ any o various reslrls which are ordinarily used as a binder, ~or instance, thermoplastic polyurethane resins; cellulose derivatives such as nitrocellulose, cellulose acetate, cellulose acetate butyrate, etc.; vinyl chloride/vinyl acetate resins such as vinyl chloride/vinyl acetate copolymer, vinyl chloride/
vinyl acetate/vinyl alcohol copolymer, vinyl chloride/vinyl acetate/male~c acid copolymer, etc.; vlnylidene chloride resins such as vinyl~idene chloride/vinyl chloride copolymer, vinylidene chloride/acrylonitrlle copolymer, etc.; polyester resins such as a~kyd resin, linear polyester, etc.; acrylic resins such as (meth)acrylic acid/acrylonitrile copolymer,~ methyl (meth)acrylate/acrylo-nitrile copolymer, etc.; acetal resins such as polyvinyl acetal, polyvinyl butyral, etc.;~phenoxy resinsj epoxy resins,~polyamide resins, butadiene/acrylonitrile copolymers, styrene/butadiene copolymers, etc., either singly or in combination.
Furthermore, convention;al r~adiation-curable compounds, such as trimethylolpropane triacrylate, may al50 be used jointly.
:
:, , 7~33~j , . .
~- When the other components ~an the crosslinked pxoduct of -the polyure-thane accord:Lng to the present invention are used together wlth khe cro~sllnk~d produc~ a~
the binder, the composition o~ the binder is preEerably so selected that the amount of the cross-linked product of the polyurethane resin is at least 5b% by weight based on the total amount of the binder.
The powders of ferromagnetic substances which can be used in the present invention include, for example, powders of ~-Fe2O3, mixed crystals of y-Fe2O3 and Fe3O4, Co-modified iron oxide, CrO2, iron, etc. Also, any fine powder of an iron-based alloy can be preferably used.
.
The particles of the fine ferromagnetic powder may have any shape, such as acicular, plate-like, spherical, etc.
The magnetic layer~ of the magnetic recording meidum according to the present invention may comprise additives such~as dispersant, lubricant, antistatic agent, abrasive, etc~., in addition to the binder and the ferromagnetic powder.
The crosslinklng of the urethane oligomer and the polyurethane resi~ according to the present invention is preferably carried out by uslng radlations, particularly, electron beams. The dosage of the electron beams is generally 0.5 to 20 Mrad. ~
~ .
~ ' - . , . :., ~ . . - :`
, ~2~ 783~
_ 23 -The non-magnetic support ~or ~lse in producing the magnetic recording medium according ko the pre~ent invention may be ~ormed o, or examp~e, a polyester such as polyethylene terephthalate; a polyolefirl such as polyethylene, polypropylene~ etc.; a cellulose derivative such as cellulose triacetate, cellulose diacetate, etc.;
a polycarbonate; polyvinyl chloride; a polyimide; a plastic such as aromatic polyamidei a metal such as Al, Cu, etc.; a paperj or the like. The form of the non-magnetic support may be any of film, tape, sheet, disk, card, drum, etc. The surface of the support may be treated with corona dlscharge, radiations, UV rays or the like, or may be precoated with an appropriate resin.
EXAMPLES
The present invention will now be explained more in deetail below while referring to nonlimitative Synthetic Examples and Examples.
In the following examples, the term "parts"
means "parts by;weight".
<Synthetic Example 1 of ~9~L~ah~ne ~ A>
A reaction vessel equipped with a thermometer, ~ stirrer and a reflux condenser was charged with 200 parts : : .
: ; :
:
~.X~ 33 of methyl ethyl ketone, 79 parts of the dlhydroxyl compound having the followlng ~ormula (I~I), R0 - CHz- Cllz ~ N- Cll~- Cll ~ - 011 I
~=~ O
.
NN -:~C~31 ~I~H ( m ) ~o - c o 1 11 , 0 - CH2- CHz- 0 - C- CH= CH2 ~ 70.5 parts of tolylene:diisocyanate (a ao:20 mixture of .~ 2,4-tolylene~di~isocyanate and 2~,6-tolylene diisocyanate) : and 0.2 part of~hydroquinone, and the resultant mixture : was~:stirred at 70C for 4 hours.: Thenj 202 parts of polybutylene:adipate having a::molecular weight of 500 (with : hydroxyl~group at both terminals of the molecule : thereo ) : : and 400 parts of methyl ethyl ketone : were~added to~the reaction mixture,~and the resultant i ~ : : ~ :
~ axmixture was:~stirred at 75C for 6:hours to obtain a :~ urethane oligomer.: : ~
Further,~800 parts~of:polybutylene e~ipa+~ h~mg a molecular weight of l,OOO (with~ hydroxyl group at both terminals of ~he molecule thereof), 108 parts of 1,4-: butanediol, 416:~parts of neopentyl glycoI,~l,S00 parts : ~ :
, : :
:,: ~ : : :
: :
7~
of diphenylmethane-4,4'-diisocyanate, 0.3 part of dibutyltin dilaurate and 3,000 parts of methyl ethyl keto~e were placed into the reaction vessel, and the re~ultank ~ixtl1re was stlrred at 80C Eor 10 hours to obtain a polyurethane resin (PV-l).
The average molecular weight of the thus obtained resin determined by gel permeation chromatography was 16,000O
~ -:
<Synthetic Example 2 of Polyurethane Resin>
The same reaction vessel as that used in Synthetic : Example 1 was charged with 400 parts of methyl ethyl ketone, 198 parts of the dihyroxyl compound having the general ;: : formula (III) used in Synthetic Example 1, 224 parts of ~ isophorone dlisocyanate and 0.2 part of hydroquinone, and :~ the resultant mixture was stirred at 70C for 6 hours. :
:~ Then, 500 parts of polytetramethylene glycol having a molecular weight of 500 and 800 parts of methyl ethyl ketone were~added to the reaction system, and the resultant ~ admixture was stirred at 75C for 8 hours.to:obtain a urethane oligomer. ~ .
Furthsr, 500 parts of polybutylene adipate :-having a molecular weight of l,000 (with hydroxyl. group : at both terminals of the molecule thereof) r 260 parts of ::
;~
::: :
~ , , , ,: : , , .
~ ~37~3~;
neopentyl glycol, 153 parts of 1,6-hexanedlol, 1,225 parts of diphenylmethane-4,4'-diisocyana~e~ 0.3 part of dibutyltin dilaurate and 1~800 parts o~ methyl ethyl ketone were added to the reactlon ves~el, and the rssultant mlxture was stirred at 80C for 10 hours to obtaiTI a polyurethane resin (PU-2).
The average molecular weight of the thus obtained resin determined by gel permeation chromatography was 30,300.
<Synthetic Example 3 of Polyurethane Resin>
A polyurethane resin was obtained in the same manner as in Synthetic Example 1.
Then, to 800 parts of the polyurethane resin (which had an average molecular weight of 16,000 as determined by gel permeation chromatography), 26 parts of diphenylmethane-4,4'-diisocyanate was added, and the resultant mixture was stirred at 80C for 7 hours to form a polyurethane resin having isocyanate group at both terminaIs of the main chain thereof. Further, 12 parts of 2-hydroxyethyl acrylate was added to the reaction vessel, and the resultant mixture was stirred at 80C for 8 hours to obtain a polyurethane resin tPU-3) having acryloyl group at both terminals of the main chain thereof~
:
- . , . , . . - . . .
33~
<Synthetic Example 4 of Polyurethane Resln>
A polyurethane resin was obtained in the same manner as in Synkhetic Example 2.
'rhen, to 1,515 part~ o~ the thus obtained polyurethane resin (which had a molecular welght of 30,300 as determined by gel permeation chromatography), 13 parts of 2-hydroxyethyl methacryalte was added, and the resultant mixture was stirred at 80C for 8 hours to obtain a polyurethane resin (PU-4) having methacryloyl group at both terminals of the main chain thereof.
<Synthetic Example 5 of Polyurethane Resin>
In the same manner~as in Synthetic Example 1 except that the dihydorxyl compound having the formula (III) used in Synthetic Example 1 was replaced by 88.6 parts of the dihydroxyl compound having the following formula (IV), H0 ~ Cl12-~C}Iz - N- CH 2 - CH 2 - 0H
C= O ,' : NH
CHz Cll~
X
C H 3 7~ ~
C H 3 : N
O = C O
0~ CH2--CH2--O--C--CH--CHz :~
, , - . ` :. .
~ ~37~3~i a polyurethane resin (PU-5) was obtained.
The average molecular weight of the thu~
obtained resin determined by gel permeation chromatography was 15,700.
<Synthetic Example 6 of_P~y~rethane Resin> .
A reaction vessel equipped with a thermometer, -a stirrer, a reflux-type condenser tube and a nitrogen gas inlet tube was charged with 270 parts of methyl ethyl ketone, 270 parts of cyclohexane, 160 parts of polybutylene adipate diol (having an average molecular weight of 1~000 as determined by terminal group analysis), 18 parts of 1,4-butylene glycol, 52 parts of 2,2'-dimethyl-1,3-propanediol, 39.5 parts of the dihydorxyl compound having the formula (III) used in Synthetic Example 1, 233.5 parts of diphenylmethane'4,4'-diisocyanate, 0.3 part of dibutyltin dilaurate as catalyst and 0.2 part o~ hydroquinone as polymerization inhibitor, and the resultant mixture was stirred at 80C for 10 hours to obtain a polyurethane resin~
Then, 14 parts of diphenylmethane-4,4'-diisocyana~e was further added to the reaction system, and the resultant mixture was stirred at 80C for 5 hours. Thereafter, 6.5 :
parts of 2-hydroxyethyl acrylate was added to the reaction '' system, and the resultant admixture was stirred st 80C for :. :
,-:
-.
.
5 hours to obtain a polyurethane resin (PU-6) having acryloyl group at both terminals o~ the main chain thereof.
The molecualr weight of the thus obtained resin determined by gel permeation chromatography was 19,900.
EXAMPLES 1 to 6:
Each of the compositions A to F shown in Table 1 was kneaded in a ball mill for 24 hours to obtain respective magnetic paints.
Then, each of the magnetic paints was applied to a 70-~m thick polyethylene terephthalate film so that the thickness of the coating after dried was 2 ~m,and the resultant coatings were irradiated with electron beams with a dosage of 5 Mrad.
Each of the thus obtained films was cut to form a floppy disk 5.25 inches in diameter, and the durability of each floppy disk was evaluated by fittlng the floppy disk into a floppy disk drive and measuring the period of time required for the reproduction output to be lowered to 50% of the initial level, at 20C and at 40C. The results are shown in Table 2.
- , . . . .
: ' , ~ . ' ,. '. ',,: ' ' .' ~ ' 7~33 Table 1 _ Paint compo- A B C D E F
~ents of paint~~~
_ P U 1 - ~ 45 1 30 _ _ _ 3 ~ I 1 40 PU, 6 . - . . . . 40 .
. VAGHI) 15 . 10 . 5 TM P TA 2~ 5 5 10 _ 10 S
CO - r - Fe~O~ ~ 100~100 100 100 100 100 Carbon black 3 3 3 3 3 3 h ¦ AbraSlve3 3 . 3 3 3 3 . Lubricant8 8 8 8 8 8 : S Dispersant2 2 2 2 2 2 ~ Methyl ethyl k0k~300300300300 300 300 Notes: 1) vinyl chloride/vinyl acetate copolymer, produced by Union Carb1de Corporation, USA
2) tri;methylolpropane triacrylate 3) Co-coated y-Fe203 ;:
.
,:
.
Table 2 ' l'' Examples ¦ Magnetic Durabllity u Ider drive (hr) , . . palnt at 20C at 40C
Example 1 A loo or more 100 or more .Example 2 B : " ,~
. Example 3 ~ D: ~ ~
Example 4 E .. ~ : :
Example 5 Example 6 F .. ..
_ . ._ ~.
::
<Synthetic Example (1) of Urethane Oligomer>
A reaction vessel equlpped with a thermometer, :
a stirrer and a reflux condenser was charged with 400 parts of methyl ethyl ketone, 198 parts of the d~hydroxyl compound having the following Pormula (III) t HO - CHz--CH2--N--CHz--CHz--OH :
CY O
NH
I
o--~ : O ~ ' 11 ,, O--CHz--GHz--O--C--CH=CHs ,, . . ~: ,'' . ", ,~
. .
.. . . . . .
:... .
. .
37~
174 parts of tolylene diisocyanate (a 80:20 mixture o-f 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate) and 0.2 part of hydroquinone, and the resultant mixture was stirred at 70C for 4 hours. Then, 1,000 parts of polybutylene adipate having a molecular weight of 1,000 -~
twith hydroxyl group at~both terminals of the molecule thereof) and 800 parts of methyl ethy1 ketone were added to the reaction system, and the resultant mixture was stirred at 75C for 6 hours to obtain a urethane oligomer.
.
cSynthetic Example (2) of Urethane Oligomer>
700 parts of the urethane oligomer having hydroxyl group at both terminals of the main chain thereof obtained in Synthetic Example (1) was transferred into another reaction vessel together with the reaction solvent, then 126 parts of diphenylmethane-4,4'-diisocyanate was added thereto, and the resultant mixture was stirred at 80~C for 8 hours. Thereafter, sa parts of 2-hydroxyethyl acrylate was added to the reaction system, and the resultant admixture was stirred at 80 QC for 8 hours to obtain a urethane oligomer having acrylocyl group at both terminals~of the main chain thereof.
.
.. ' . . . ' .: .
.; , . .
~ 37~
<Synthetic Example (3) of Urethane Oli~omer>
The same reaciton vessel as that usea in Synthetic Example (1) was chaxged with 350 parts of methyl ethyl ketone, 198 parts of the dihydorxyl compound having the general formula (III) used in Synthetic Example (1), 130.5 parts of tolylene diisocyanate used in Synthetic Exmaple (1) and 0.2 part of hydroquinone, and the resultant mixture was stirred at 80C for 8 hours~ Then, 250 parts -of ~-caprolactone glycol (molecular weight: 500) and 250 parts of methyl ethyl ketone were added to the reaction system, and the resultant admixture was stirred at 80C for 8 hours to obtain a urethane oligomer having hydroxyl group at both teFminals of the molecule thereof.
<Synthetic Example (4) of Urethane Oligomer~
300 parts of the urethane oligomer obtained in Synthetic Example (3) was transferred into another reaction vessel together w1th the reaction solvent, then 32.5 parts of 2-hydroxyethyl methacrylate was added thereto, and the resultant admixture was stirred at 80C for 8 hours to obtain a~urethane oligomer having mechacryloyl group at both terminals of the main chaln thereof.
..
7~3~;
EXAMPLES 7 to 10 and COMPARATIVE EX~MPLES 1 and 2:
Each of the compositions G to J shown in Table 3 was kneaded in a ball mill for 24 hours to obtain respective magnetic paints~ :
Then, each of the magnetic paints was applied to a 70-~m thick polyethylene terephthalate film so that the thickness of the coating after dried was 2 ~m, and the resultant coatings were i~radiated with electron beams with a dosage of 5 Mrad:~
Each of the thus obtained films was cut to form a floppy disk 5.25 inches in diameter, and the durability of ~he floppy disk was evaluated b~ fitting the floppy disk into a floppy disk drive and meas~ring-the period of time required for the repro~uction output...to be lowered to 50~ of the initial level~ at 20C and at 40C. The resuIts æe shown in Table 4.
By way of comparison, magnetic paints K and L ;
shown in Table 3 were prepared in the same manner as above.
Only the magnetic paint K was subjected, after 24-hour kneading, to kneading for 1 hour by adding thereto 10 parts trade ~ark of a curing agent (~e~uh}-hRme: COLONATE L, produced by Nlppon Polyurethane Kogyo K.K.~. Next, the thus prepared paint was applied to a 70-~m thick polyethylene terephthalate film so that the thickness of the coating . - - . . - , , :. .. .
_ 35 -after dried was 2 ~m, and was dried and aged. Then, the thus obtained film was cut to form a floppy dlsk 5.25 inches in diameter, and the durability of the floppy disk was evaluated by fitting the floppy disk into a floppy disk drive and measuring the period of time required for the reproduction output to be lowered to 50%
of the initial level, at 20C and at 40C.
On the other hand, the magnetic paint L was treated in the same manner as the magnetic paints G to J, thereby forming a floppy disk, and the durability of the thus obtained floppy disk was evaluated by fitting the floppy disk into a floppy disk drive and measuring the period of time required for the reproduction output to be lowered to 50% of the initial level. The results ;~
are shown in Table 4.
:
. .
.
~,, ,, ,, : , ' :, ~:, ' , . . .
, .
~3~
Table 3 _ Ex~e E~le E~ple Ee~le Co~xIa Co~xra-. 7 8 9 10 ~ive E~, tiV2e EX-_ .. _ _ _ _ . = etic p~nt G H I J K L
_~ . _ ._ . __ _ Synthetic Ex.~l~ 30 Synthetic Ex.(2~ ~ 35 . Synthetic Ex.(3) . 40 c Synthetic Ex.(4) : . 40 . V A G Ha) 5 10 ~5 ~ . 20 15 N - ~ 3 0 4 2~ 5 , 5 ~ ~
T M P ~ A~ 10 5 5 10 _ _ ....
- r - Fe~0~ 'j 100 1~ 100 100 100 100 3 Carbon black 3 : 3 3 3 3 3 ;~ Abrasive 3 3 3 3 . -3 3 :~ Lubricant 8 8 8 8 8 . 8 ~ Cyclohexane 150 150 150 150 150 150 : ~ Methyl et~y} k*~ne 100 100 100 100 100 100 Notes: 1) vinyl chloride/vinyl acetate copolymer,:produced : by Union Carbide Corporation, USA
2) thermoplastic polyurethane resin, produced by Nippon Polyurethane Kogyo K.K.
: 3) trimethylolpropane triacrylate ~ 4) Co-coated y-Fe2O
:
,: . ,, : . .
: ;
33~;
Table 4 . .
Examples and Magnetic D~iliky wx~rdrive (hr) Comparativ~ Example paint ~ at 20C at 40C
_ ~~
Example 7 G 100 or more 100 or more .
Example 8 H .. "
Example 9 I "
Example 10 J _ _ _ ll Comparative Ex. 1 K 10 or less 10 or less Comparative Ed. 2 L ll "
., ---- __ : , ; ' Examples concerning the dihydorxyl compound will now be descrlbed below. .
EXAMPLE 11: ~
A first-stage reaction was carried out by charging a reaction vessel having a stirrer, a thermometer and a reflux condenser attached thereto with 100 parts of 2,4-tolylene dilsocyanate, 66.7 parts of 2-hydroxyethyl acrylate and 0.1 part of hydroquinone, and stirring the ;
resultant mixture at 40F for 1 hour and then at 60C for 3 hours.
~' :
~ ~ -:
' ' " ' ':' - , .
.. : . ..
, ~- : .: . : , : ~ . , Next, a second-stage reaction was carried out as follows. To the reaction vessel was added 667 parts of methyl ethyl ketone, the reaction system was then cooled to 5C, and 60.3 parts of diethanolamine was added dropwise to the reaction system at that temperature over 1 hour.
After the dropwise addition, the resultant admixture was stirred at 20C for 6 hours, and then methyl ethyl ketone was distilled off to obtain a white powder.
The compound obtained on the first-stage reaction was subjected to detexmination of isocyanate concentration (by a ~i-n-butylamine/hydrochloric acid titration method), and the concentration was found to be about 1/2 times the value before the reaction. The residual isocyanate in the compound was reacted with ethanol, and after capping, the compound was analyzed by li~uid chromatography (column: Hibar Lechrosorb Si-60;
solvent: 0.5% methanol-containing dichloromethane). The analytical result showed that the compound was a compound having the following formula (IV).
CH~
~J
HN
oc~ O
O--C H z--C H 2--O--C--C H--C H 2 ~I racle-fnRrk '', . ' '' . ` ' , ~, - : ~
. -"
,' ~ . .
',' : ' ,' ' ,' ' ' ~ ' ' : ' , :
. .
783~;
The shite powder obtained upon the second-stage reaction was subjected to potentiometric titration using perchloric acid, whereby it was confirmed that amino groups had disappeared. It was also confirmed by the above mentioned di-n-butylamine/hydrochloric acid titration method that isocyanate groups had di~appered.
. Furtherj it was confirmed by NMR that the white powder finally obtained was a compound having the following formula (V)O
1 H-NMR ( solvent DMSO-d ) ~ : internal standard TSP
2.1 ~2.3 . Ar--CH3 ~) 3.2 ~4.3 -CH2-- . Q ~ ~;) (~) N
6 . 0 ~ 6 . 5 - C = C 0 (: 3 O
H H
7. 0 ~8. 4 Ar--H ~ ~3 HO--CH ~--CH z--N--CH 2--CNz--OH
O = C
~C~H (v) ~) N/~H (~) :
0 O--C~ O H (5~) I (~i) (~) 11 (~) I
o-- CNz--CH2--O--C~ CH= C
H ( ~) . , . . ., ~ ..
, , : ,: -:. :, . .. . , :
; ~ - -- ~ :
Then, a reaction vessel equipped with a stirrer, a thermometer and a reflux condenser was charged with 60.7 parts of the compound of the formula (V), 100 parts of polybutylene adipate (number average molecular weight:
1,000), 16 parts of 2,2-dimethyl-1,3-propanediol, 8 parts of 1,4-butylene glycol, 154 parts of diphenylmethane-4,4'-diisocyanate and 390 parts of methyl ethyl ketone, and .:
the resultant mixture was stirred at 80C for 12 hours, to obtain a viscous liquid. When methyl ethyl ketone was distilled o~f from the viscous liquid, a polyurethane ~ .
resin was obtained as a single mass. :
.:EXAMPLE 12:
A shite powder was obtained in the :same manner as in Example 11 except that 92.5 parts of dibutanolamine was used in place of the diethanolamine used in Example 11. The white powder thus obtained was analyzed in the .
same manner as in Example 11, and was found to be a compound , having the following formula (VI).
HO - CH2 - CH2 - CH2 - CHz - N- CH2 - CH2- CH~ - CNz- OH
'' C--:O
NH ~-C ~ ~ (VI) : . N
I
0=~ 0 Il O - CH2 - CHz- O - C- CH- CHz "
: . ,, . .:, - . .,, : .. .
Then, 69.3 parts of the thus obtained compound of formula (VI) was subjected to a reaction in the same manner as in Example ll, to obtain a polyurethane resin.
.
.
Claims (30)
1. A magnetic recording medium which comprises a non-magnetic support and a magnetic layer, coated on the support, com-prising a binder and powder of a ferromagnetic substance dispersed in the binder, said binder comprising a crosslinked product of a polyurethane having a main chain and an average molecular weight of 900 to 50,000 (as determined by gel permeation chromatography), comprising at least one unit of the formula (I):
(I) (in which R1, R2 and R4 are each an alkylene, R3 is a hydrocarbon group derived from a diisocyanate compound and R5 is hydrogen or methyl) and having -OH, -NCO or -OOC-CR5=CH2 at both terminals of the main chain thereof, provided that the terminals of the main chain thereof are not -NCO when the molecular weight of the polyurethane ranges from 900 to less than 10,000.
(I) (in which R1, R2 and R4 are each an alkylene, R3 is a hydrocarbon group derived from a diisocyanate compound and R5 is hydrogen or methyl) and having -OH, -NCO or -OOC-CR5=CH2 at both terminals of the main chain thereof, provided that the terminals of the main chain thereof are not -NCO when the molecular weight of the polyurethane ranges from 900 to less than 10,000.
2. A medium as claimed in Claim 1, in which said poly-urethane has a molecular weight of 900 to less than 10,000 and the terminals of the main chain are -OH or -OOC-CR5=CH2.
3. A medium as claimed in Claim 1, in which said poly-urethane has a molecular weight of 10,000 to 50,000 and the ter-minals of the main chain are -OH, -NCO or -OOC CR5=CH2.
4. A medium as claimed in Claim 1, in which said poly-urethane has a molecular weight of 10,000 to 35,000 and the terminals of the main chain are -OH, -NCO or -OOC-CR5-CH2.
5. A medium as claimed in claim 1, in which R3 is a hydrocarbon group derived from a diisocyanate selected from the group consisting of m-phenylene diisocyanate, p-phenylene diisocyanate, 1-chloro-2,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, ethane diisocyanate, propane di-isocyanate, butane diisocyanate, pentane diisocyanate, hexane diisocyanate, heptane diisocyanate, octane diisocyanate, nonane diisocyanate, decane diisocyanate, and isophorone diisocyanate;
R4 is an alkylene of the formula:
(in which R6 is (1) hydrogen, (2) an alkyl having 1 to 10 carbon atoms or (3) -CH2-R7, where R7 is a substituent selected from the group consisting of halogen, acryloxy, methacryloxy, allyloxy, cinnamyl, phenoxy [in which the phenyl radical may be further substituted by chloro], lower alkanoyloxy, lower chlorinated alkanoyloxy, benzoxy [in which the phenyl radical may further be substituted by chloro], phenoxyacetoxy [in which the phenyl radical may further be substituted by chloro, crotonoxy and cinnamyloxy);
and R1 and R2 are each an alkylene having 2 to 8 carbon atoms.
R4 is an alkylene of the formula:
(in which R6 is (1) hydrogen, (2) an alkyl having 1 to 10 carbon atoms or (3) -CH2-R7, where R7 is a substituent selected from the group consisting of halogen, acryloxy, methacryloxy, allyloxy, cinnamyl, phenoxy [in which the phenyl radical may be further substituted by chloro], lower alkanoyloxy, lower chlorinated alkanoyloxy, benzoxy [in which the phenyl radical may further be substituted by chloro], phenoxyacetoxy [in which the phenyl radical may further be substituted by chloro, crotonoxy and cinnamyloxy);
and R1 and R2 are each an alkylene having 2 to 8 carbon atoms.
6. A medium as claimed in claim 5, wherein R3 is a hydro-carbon group derived from a diisocyanate having two isocyanate groups with different reactivities.
7. A medium as claimed in claim 6, wherein R3 is a hydro-carbon group derived from 2,4-toluene diisocyanate or isophorone diisocyanate.
8. A medium as claimed in claim 5, wherein R4 is an alky-line having 2 or 3 carbon atoms and R1 and R2 are each an alkylene having 2 to 4 carbon atoms.
9. A medium as claimed in claim 6, wherein R4 is -CH2CH2-and R1 and R2 are each -CH2CH2-, -CH2CH2CH2- or CH2CH2CH2CH2-.
10. A medium as claimed in claim 7, wherein R4 is -CH2CH2-and R1 and R2 are each -CH2CH2-, -CH2CH2CH2- or -CH2CH2CH2CH2-.
11. A medium as claimed in claim 5, 6 or 7, in which said polyurethane has a molecular weight of 900 to less than 10,000 and the terminals of the main chain are -Oh or -OOC-CR5-CH2.
12. A medium as claimed in claim 5, 6 or 7, in which said polyurethane has a molecular weight of 10,000 to 50,000 and the terminals of the main chain are -OH, -NCO or -OOC-CR5=CH2.
13. A medium as claimed in claim 5, 6 or 7, in which said polyurethane has a molecular weight of 10,000 to 35,000 and the terminals of the main chain are -OH, -NCO or -OOC-CR5=CH2.
14. A medium as claimed in claim 8, 9 or 10, in which said polyurethane has a molecular weight of 900 to less than 10,000 and the terminals of the main chain are -OH or -OOC-CR5=CH2.
15. A medium as claimed in claim 8, 9 or 10, in which said polyurethane has a molecular weight of 10,000 to 50,000 and the terminals of the main chain are -OH, -NCO or -OOC-CR5=CH2.
16. A medium as claimed in claim 8, 9 or 10, in which said polyurethane has a molecular weight of 10,000 to 35,000 and the terminals of the main chain are -OH, -NCO or -OOC-CR5=CH2.
17. A process for producing the magnetic recording medium as defined in claim 1, which process comprises:
applying a magnetic paint comprising the binder, the ferromagnetic substance powder and a solvent to a surface of the support, drying off the solvent from the paint, and applying radiation to the dried paint, thereby cross-linking the polyurethane.
applying a magnetic paint comprising the binder, the ferromagnetic substance powder and a solvent to a surface of the support, drying off the solvent from the paint, and applying radiation to the dried paint, thereby cross-linking the polyurethane.
18. A process as claimed in claim 17, wherein the poly-urethane is produced by a process comprising:
(i) reacting a diisocyanate compound with a dihydroxyl com-pound of the formula:
(II) (in which R1, R2 and R4 are each an alkylene, R3 is a hydrocarbon group derived from a diisocyanate compound and R5 is H or CH3) at a diisocyanate compound/dihydroxyl compound molar ratio of above 1.5 to about 2.0, thereby forming an isocyanate-terminated pre-polymer, and (ii) reacting the isocyanate-terminated prepolymer obtained in step (i) with a diol at a prepolymer:diol molar ratio of from about 1:1.5 to about 1:2.0, thereby forming a urethane oligomer having -OH at both terminals and a molecular weight of 900 to less than 10,000.
(i) reacting a diisocyanate compound with a dihydroxyl com-pound of the formula:
(II) (in which R1, R2 and R4 are each an alkylene, R3 is a hydrocarbon group derived from a diisocyanate compound and R5 is H or CH3) at a diisocyanate compound/dihydroxyl compound molar ratio of above 1.5 to about 2.0, thereby forming an isocyanate-terminated pre-polymer, and (ii) reacting the isocyanate-terminated prepolymer obtained in step (i) with a diol at a prepolymer:diol molar ratio of from about 1:1.5 to about 1:2.0, thereby forming a urethane oligomer having -OH at both terminals and a molecular weight of 900 to less than 10,000.
19. A process as claimed in claim 18, wherein the process for producing the polyurethane further comprises:
(iii) [a] reacting the OH-terminated urethane oligomer ob-tained in step (ii) with a diisocyanate compound to once convert the terminals to isocyanate groups and then reacting the resulting product with a compound having a (meth)acrylic double bond and an isocyanate-reactive group, or [b] reacting the OH-terminated urethane oligomer obtained in step (ii) with (meth)acrylic acid or a lower alkyl ester thereof, thereby both in variant [a] and [b] forming a urethane oligomer having (meth)acryloyl terminals.
(iii) [a] reacting the OH-terminated urethane oligomer ob-tained in step (ii) with a diisocyanate compound to once convert the terminals to isocyanate groups and then reacting the resulting product with a compound having a (meth)acrylic double bond and an isocyanate-reactive group, or [b] reacting the OH-terminated urethane oligomer obtained in step (ii) with (meth)acrylic acid or a lower alkyl ester thereof, thereby both in variant [a] and [b] forming a urethane oligomer having (meth)acryloyl terminals.
20. A process as claimed in claim 18, wherein the process for producing the polyurethane further comprises:
(iv) reacting a diisocyanate compound with a polyol component which contains the OH-terminated urethane oligomer obtained in step (ii) and may contain other polyol at an OH/NCO molar rakio of from about 1/D.85 to about 1/1.15, thereby forming a polyure-thane resin having a molecular weight of 10,000 to 50,000 and -OH
or -NCO at both terminals.
(iv) reacting a diisocyanate compound with a polyol component which contains the OH-terminated urethane oligomer obtained in step (ii) and may contain other polyol at an OH/NCO molar rakio of from about 1/D.85 to about 1/1.15, thereby forming a polyure-thane resin having a molecular weight of 10,000 to 50,000 and -OH
or -NCO at both terminals.
21. A process as claimed in claim 20, wherein the process for producing the polyurethane further comprises:
(v) reacting a polyurethane resin having -NCO at both ter-minals obtained in step (iv) with a compound having a (meth) acryloyl double bond and an isocyanate-reactive group at a poly-urethane: (meth)acryloyl compound molar ratio of about 1:2.
(v) reacting a polyurethane resin having -NCO at both ter-minals obtained in step (iv) with a compound having a (meth) acryloyl double bond and an isocyanate-reactive group at a poly-urethane: (meth)acryloyl compound molar ratio of about 1:2.
22. A polymerizable dihydroxyl compound having the following general formula (II):
(II) (in which R1, R2 and R4 each are an alkylene, R3 is a hydrocarbon group and R5 is hydrogen or methyl).
(II) (in which R1, R2 and R4 each are an alkylene, R3 is a hydrocarbon group and R5 is hydrogen or methyl).
23. A compound as claimed in claim 22, in which R3 in the general formula (II) is a hydrocarbon group derived from a diiso-cyanate compound.
24. A compound as claimed in claim 22 in which:
R3 is a hydrocarbon group derived from a diisocyanate selected from the group consisting of m-phenylene diisocyanate, p-phenylene diisocyanate, 1-chloro-2,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, ethane diisocyanate, propane diisocyan-ate, butane diisocyanate, pentane diisocyanate, hexane diisocyan-ate, heptane diisocyanate, octane diisocyanate, nonane diisocyan-ate, decane diisocyanate, and isophorone diisocyanate;
R4 is an alkylene of the formula:
(in which R6 is (1) hydrogen, (2) an alkyl having 1 to 10 carbon atoms or (3) -CH2-R7, where R7 is a substituent selected from the group consisting of halogen, acryloxy, methacryloxy, allyloxy, cinnamyl, phenoxy [in which the phenyl radical may be further substituted by chloro], lower alkanoyloxy, lower chlorinated alkanoyloxy, benzoxy [in which the phenyl radical may further be substituted by chloro], phenoxyacetoxy [in which the phenyl radical may further be substituted by chloro], crotonoxy and cinnamyloxy);
and R1 and R2 are each an alkylene having 2 to 8 carbon atoms.
R3 is a hydrocarbon group derived from a diisocyanate selected from the group consisting of m-phenylene diisocyanate, p-phenylene diisocyanate, 1-chloro-2,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, ethane diisocyanate, propane diisocyan-ate, butane diisocyanate, pentane diisocyanate, hexane diisocyan-ate, heptane diisocyanate, octane diisocyanate, nonane diisocyan-ate, decane diisocyanate, and isophorone diisocyanate;
R4 is an alkylene of the formula:
(in which R6 is (1) hydrogen, (2) an alkyl having 1 to 10 carbon atoms or (3) -CH2-R7, where R7 is a substituent selected from the group consisting of halogen, acryloxy, methacryloxy, allyloxy, cinnamyl, phenoxy [in which the phenyl radical may be further substituted by chloro], lower alkanoyloxy, lower chlorinated alkanoyloxy, benzoxy [in which the phenyl radical may further be substituted by chloro], phenoxyacetoxy [in which the phenyl radical may further be substituted by chloro], crotonoxy and cinnamyloxy);
and R1 and R2 are each an alkylene having 2 to 8 carbon atoms.
25. A compound as claimed in claim 24, wherein R3 is a hydrocarbon group derived from a diisocyanate having two isocyanate groups with different reactivities.
26. A compound as claimed in claim 25, wherein R3 is a hydrocarbon group derived from 2;4-toluene diisocyanate or iso-phorone diisocyanate.
27. A compound as claimed in claim 24, 25 or 26, wherein R4 is an alkylene having 2 or 3 carbon atoms and R1 and R2 are each an alkylene having 2 to 4 carbon atoms.
28. A compound as claimed in claim 24, 25 or 26, wherein R4 is -CH2CH2- and R1 and R2 are each -CH2CH2-, -CH2CH2CH2- or -CH2CH2CH2CH2-.
29. A process for producing a dihydroxy compound of the formula (II) defined in claim 22, 23 or 24, which process comprises:
(a) reacting a diisocyanate compound of the formula:
with a hydroxyalkyl (meth)acrylate compound of the formula:
thereby producing an intermediate of the formula:
, and (b) reacting the intermediate with a dialkanol amine of the formula:
HO - R1 - NH - R2 - OH.
(a) reacting a diisocyanate compound of the formula:
with a hydroxyalkyl (meth)acrylate compound of the formula:
thereby producing an intermediate of the formula:
, and (b) reacting the intermediate with a dialkanol amine of the formula:
HO - R1 - NH - R2 - OH.
30. A process which comprises:
(i) reacting a diisocyanate compound with a dihydroxyl compound of the formula (II) defined in claim 22, 23 or 24 at a diisocyanate/dihydroxyl compound molar ratio of about 1.5 to about 2.0, thereby forming an isocyanate-terminated prepolymer, and (ii) reacting the prepolymer with a diol at a prepolymer:diol molar ratio of from about 1:1.5 to about 1:20, thereby forming a urethane oligomer having -OH at both terminals and a molecular weight of 900 to less than 10,000.
(i) reacting a diisocyanate compound with a dihydroxyl compound of the formula (II) defined in claim 22, 23 or 24 at a diisocyanate/dihydroxyl compound molar ratio of about 1.5 to about 2.0, thereby forming an isocyanate-terminated prepolymer, and (ii) reacting the prepolymer with a diol at a prepolymer:diol molar ratio of from about 1:1.5 to about 1:20, thereby forming a urethane oligomer having -OH at both terminals and a molecular weight of 900 to less than 10,000.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11037487A JPS63275556A (en) | 1987-05-06 | 1987-05-06 | Novel polymerizable dihydroxyl compound |
| JP110374/87 | 1987-05-06 | ||
| JP18473687A JPS6430021A (en) | 1987-07-24 | 1987-07-24 | Magnetic recording medium |
| JP184734/87 | 1987-07-24 | ||
| JP18473487A JPS6430020A (en) | 1987-07-24 | 1987-07-24 | Magnetic recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1287836C true CA1287836C (en) | 1991-08-20 |
Family
ID=27311716
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 565958 Expired - Fee Related CA1287836C (en) | 1987-05-06 | 1988-05-05 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1287836C (en) |
-
1988
- 1988-05-05 CA CA 565958 patent/CA1287836C/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |