JPH01286114A - Magnetic tape with back coating layer - Google Patents

Abstract

PURPOSE:To obtain excellent resistance to heat and scratching by coating a component essentially consisting of a specific phosphazene compd. having a polymn. curable group as a back coating layer on the rear surface of the magnetic tape. CONSTITUTION:The coating material essentially consisting of the curable phosphazene compd. having the repeating unit expressed by general formula I and having >=3 degrees of polymn. is coated as the back coating layer on the rear surface of the magnetic tape and is cured. In formula, (a), (b) are a>0, b>=0 and denote the real number satisfying a+b=2; A denotes a polymn. curable group, B denotes a non-polymn. curable group. General formula I is the display as an average value of the mixture composed of several kinds of compds. Therefore, (a) and (b) are not always limited to the integers and are the real number including decimals as well. The back coating layer having a small coefft. of friction and excellent durability and wear resistance is thereby formed on the rear surface of the magnetic tape.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetic tape with a back coat layer, and more specifically, a specific phosphazene compound is coated on the back side of various magnetic tapes such as audio magnetic tape and video magnetic tape. The present invention relates to a magnetic tape with a back coat layer, which has a back coat layer and has various excellent performances.

[Problems to be solved by conventional techniques and inventions] In recent years,
Various types of magnetic tapes, such as audio magnetic tapes and video magnetic tapes, are trending toward higher quality and higher image quality, and are required to have a high degree of running stability. Furthermore, they are often placed in high temperature and high humidity environments such as inside automobiles, and therefore there is a demand for improved durability.

Under these circumstances, tapes in which projections are provided at various locations on the back surface of the tape have recently been developed for the purpose of improving running properties. However, when such tapes are run, the protrusions are scraped away by guides, etc., resulting in a flat surface, and the scraped powder can damage the tape, and the flattening causes an abnormally high level of friction, resulting in tape squeal and wow/flutter.
This caused problems such as an increase in the amount of water and tape sticking.

In addition, high-grade tapes are commercially available with a back coat layer because the film that serves as the substrate has high flatness. There was a problem in that it had insufficient strength and scratch resistance, and could not withstand long-term use.

Therefore, the present inventor conducted extensive research in order to develop a magnetic tape that has excellent heat resistance, scratch resistance, and excellent running stability.

[Means to solve the problem]

As a result, it has been found that the above object can be achieved by applying a component containing a specific phosphazene compound having a polymerizable curable group to the back surface of various magnetic tapes as a back coat layer and curing it. The present invention was completed based on this knowledge.

That is, in the present invention, the general formula % formula % [where a, b are a>O, b≧0, and a+b=
represents a real number satisfying 2, A represents a polymerizable curable group, and B represents a non-polymerizable curable group. ] A magnetic tape with a back coat layer, characterized in that a back coat layer is formed by curing a coating material containing a curable phosphazene compound as a main component and having a degree of polymerization of 3 or more. It provides:

The bank coat layer formed on the back side of the magnetic tape of the present invention is
As mentioned above, it is a cured coating material containing as a main component a phosphazene compound having a repeating unit represented by the general formula (CI), where the general formula (1) is
It does not represent a single compound, but the average value of a mixture of several compounds. Therefore, a and b indicating the number of each group are not necessarily limited to integers, but are real numbers including decimals. Similarly, the degree of polymerization is a real number that includes not only integers in the range of 3 or more but also decimals.

There are various phosphazene compounds having the repeating unit of the above general formula (I) depending on the type of each substituent.

In the formula, A represents a polymerizable curable group, and this polymerizable curable group refers to irradiation with ultraviolet rays, visible light, or electron beams.

It refers to a functional group that reacts and cures by using a chemical curing agent or by heating, and is usually a group having a reactive double bond. There are various types of groups having this reactive double bond, such as functional groups containing an acryloyl group, a methacryloyl group, or an allyl group.

The functional group containing an acryloyl group or the functional group containing a methacryloyl group is an acryloyloxy group, a methacryloyloxy group, or a compound of the general formula U [wherein, R' represents a hydrogen atom or a methyl group, and R2
represents an alkylene group (including a branched alkylene group) having 1 to 12 carbon atoms (preferably 1 to 5 carbon atoms). ] It is expressed as.

Specific examples 9+1 of the group represented by the general formula [■] include 2-hydroxybutyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, and 2-hydroxybutyl methacrylate.
3-hydroxyethyl methacrylate, 4-hydroxyethyl methacrylate, 5-hydroxybentyl methacrylate.

6-hydroxy-3-methylhexyl methacrylate, 5-hydroxydodecyl methacrylate.

3-Hydroxy-2-t-butylpropyl methacrylatexyl methacrylate, 3-hydroxy-2-methyl-
Residues obtained by removing hydrogen atoms from hydroxyl groups in methacrylates such as 2-ethylpropyl methacrylate and 12-hydroxydodecyl methacrylate, as well as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate 2-
Hydroxybutyl acrylate, 3-hydroxybutyl acrylate, 1-,4-hydroxybutyl acrylate.

5-hydroxypentyl acrylate 6-hydroxy-3-methylhexyl acrylate, 5-hydroxyhexyl acrylate, 3-hydroxy-2-t-butylpropyl acrylate, 3-hydroxy-2,2-dimethylhexyl acrylate 3-hydroxy Examples include residues obtained by removing a hydrogen atom from a hydroxyl group in acrylates such as -2-methyl-2-ethylpropyl acrylate and 12-hydroxydodecyl acrylate. Particularly preferred groups are 2-hydroxyethyl methacrylate residues and 2-hydroxyethyl acrylate residues.

Moreover, the functional group containing this acryloyl group or methacryloyl group is the same as that of the above-mentioned general formula (■). ], i.e., hydroxyalkyl-substituted (meta)
A residue obtained by removing a hydrogen atom from the hydroxyl group of acrylamide, and a general formula [wherein RJ is the same as above. ] Examples include functional groups represented by the following, ie, residues obtained by removing one hydrogen atom from the amino group of acrylamide or methacrylamide.

Furthermore, as a functional group containing an allyl group, in addition to the allyl group itself, for example, an allyloxy group (CHt=CH-
CHtO- ), but it is not limited to this allyloxy group, but can be broadly expressed by the general formula [wherein R1-R4 are the same as above. ], ie, a residue obtained by removing a hydrogen atom from the hydroxyl group of an allyl compound having one hydroxyl group. Specific examples of the functional groups represented by the general formulas [, V) to [■] include CHz=CH CHZ OH, CHz=
CH CH OH.

H3 CM.

r CH.

There are residues obtained by removing the hydrogen atom from the hydroxyl group in allyl compounds such as

On the other hand, B in general formula (1) is represented by the formula: R'M-
... [■] Indicates a group represented by or. Here, M in the formula [■] represents an oxygen atom, a sulfur atom, or an imino group, and RS has 1 to 1 carbon atoms.
8 alkyl group or a halogenated alkyl group having 1 to 18 carbon atoms. Specifically, alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, and octyloxy group, and substituted with halogen (e.g., fluorine, chlorine, bromine, etc.) similar alkoxy groups, alkylthio groups such as methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, heptylthio group, octylthio group, similar alkylthio groups substituted with halogen (e.g. fluorine, chlorine, bromine, etc.), Alkylimino groups such as methylimino group, ethylimino group, propylimino group, butylimino group, pentylimino group, hexylimino group, heptylimino group, octylimino group.

Similar alkylimino groups substituted with halogen (eg, fluorine, chlorine, bromine, etc.) can be mentioned. Furthermore, M in formula (IX) is the same as above, and R'-%/R
-0 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogenated alkyl group having 1 to 4 carbon atoms. Specifically, the group of formula (IX) includes a phenoxy group, a thiophenyl group, a halogenated phenoxy group (2
, 4,6-)IJ dibromophenoxy group, 4-bromophenoxy group.

2-chlorophenoxy group, 2,4-dichlorophenoxy group, etc.) and halogenated thiophenyl group (4-chlorophenylthio group, etc.), or aniline and halogenated aniline (2-chloroaniline, 2,4-dichloroaniline, 2, Examples include residues obtained by removing a hydrogen atom from the amino group of 4.6-dripromoaniline, etc.).

Furthermore, regarding a and b in the general formula CI), Ov
Any real number that satisfies a≦2.0≦b<2 and a+=2 may be sufficient, but preferably 0.6≦a≦2, 0≦b
≦1.4.

Substituent A is a group that acts when the back coat layer containing the phosphazene compound of general formula (I) as a main component is cured, and substituent B is a group that controls the physical properties of the cured product and also controls the polymerization. It is a group that exhibits the effect of regulating performance. Therefore, by appropriately selecting a and b, the physical properties of a magnetic tape having a back coat layer containing this phosphazene compound as a main component are determined.

However, since those with a=0 do not have curability, such phosphazene compounds are excluded from the components of the back coat layer of the present invention. However, a=2. b = o,
That is, a phosphazene compound having a repeating unit represented by the general formula +N P (A) r) - [I] can be used as a component of the back coat layer of the present invention.

The phosphazene compound in the present invention has the general formula (
1), the degree of polymerization is 3 or more, preferably in the range of 3 to 10,000, more preferably in the range of 3 to 18, especially 3 or 4.
Or a mixture thereof is optimal. Also, the general formula (
Although some repeating units of 1) are bonded (polymerized) in a chain, preferred are those in which the repeating units of 1) are bonded (polymerized) in a ring.

Specific examples of such phosphazene compounds are as follows.

A cyclic compound represented by

formula %formula%)] A cyclic compound represented by

formula %formula%) A cyclic compound represented by

formula %formula%) A cyclic compound represented by

(Margin below) hmm = o 　 　 　 　 　 　 　 　

幇　-P　　-P　　≦-B and so on.

Such phosphazene compounds can be produced by various methods and are not particularly limited. For example, when it is desired to introduce a group represented by the general formula (II) as a substituent A, a hydroxyalkyl (meth)acrylate corresponding to this general formula (n), that is, a general formula % formula % [where R', R2 is the same as above. ] When using a hydroxyalkyl (meth)acrylate represented by the formula [111] and introducing a group represented by the general formula [111] as the substituent A, the corresponding general formula % formula % [where R1, R2 are Same as above. ] If you want to use a hydroxyalkyl (meth)acrylamide represented by the above formula and introduce a group represented by the general formula [lV] as the substituent A, use the corresponding general formula % formula % [wherein R1 is the same as above] same. ] If you want to use (meth)acrylamide represented by or introduce a group represented by general formulas (V) to [■] as substituent A, use the corresponding general formula [where R1, R3, R4 is the same as above. ] Allyl alcohol, allylphenol, allyl ester of hydroxybenzoic acid or its derivatives are used.

On the other hand, in the group represented by the general formula [■] introduced as the substituent B, when M is an oxygen atom, SOH [in the formula, R5 is the same as above]. ] Using an alkanol, a halogenated alkanol or a derivative thereof, and when M is a sulfur atom, R' S 'H [In the formula, R5 is the same as above. ] When using an alkyl mercaptan, a halogenated alkyl mercaptan, or a derivative thereof, and when M is an imide group, R'NH.

[In the formula, RS is the same as above. ]

An alkylamine, a halogenated alkylamine, or a derivative thereof is used.

Further, in the group represented by the general formula (IX) introduced as the substituent B, when M is an oxygen atom, the general formula [wherein R6-R111 are the same as above] is used. ], and when M is a sulfur atom, the general formula [wherein R6-R111 are the same as above] is used. ], and when M is an imino group, the general formula [wherein R6 to RIG are the same as above] is used. ] Aniline or its derivatives are used.

The compound forming substituent A and the compound forming substituent B are combined into chlorophosphazene (formula (N P Cf
cyclic compound represented by fi□), or 2〇f, P
- By reacting with a chain compound represented by NPCl, -, NPCjl!3, where n is 3 or more, preferably 3 to 18, the desired phosphazene compound of general formula (I) can be obtained.

In addition, when the compound forming the above-mentioned substituted MB is an alcohol, a mercaptan, a phenol, or a thiophenol, an alkali metal such as metallic sodium or metallic potassium is reacted in advance to form an alcoholade, a phenolate, a mercaptide, It is preferable to use thiophenolates.

Further, in the reaction of the compounds forming the above-mentioned substituents A and B with chlorophosphazene, it is preferable to use a dehydrohalogenating agent such as a tertiary amine. Examples of the tertiary amine include trimethylamine, triethylamine, triisopropylamine, trin-
Examples include propylamine, tri-n-butylamine, pyridine and picoline, among which pyridine is preferred.

Furthermore, this reaction is usually carried out in an organic solvent.

Benzene and toluene are used as organic solvents.

Examples include xylene, chloroform, cyclohexane, methylene chloride, tetrahydrofuran, and 4-dioxane. These can be used alone or in combination.

Through the reaction described above, a phosphazene compound, which is the main component of the back coat layer formed on the back surface of the magnetic tape, is obtained.

In order to form a back coat layer on the back side of the magnetic tape, the above-mentioned phosphazene compound or, if necessary, a monofunctional monomer and/or polyfunctional monomer copolymerizable with the phosphazene compound and a back coat layer are added. A coating liquid (coating material) is prepared by containing commonly used additives, and this is applied to the back side of the magnetic tape and irradiated with active energy rays.
It may be hardened by heating or the like.

An example of a monofunctional monomer or polyfunctional monomer copolymerizable with a phosphazene compound is an acryloyl group.

Examples include compounds having a reactive double bond, such as various compounds having a methacryloyl group, a vinyl group, or an allyl group.

Further, examples of additives include inorganic fillers, organic fillers, lubricants, and the like.

As the inorganic filler, finely powdered silica, alumina, glass, ceramic, etc. (solvent-dispersed type may be used) can be used.

Furthermore, examples of the organic filler include acrylic resin in the form of fine powder.

The lubricant may be in any form such as liquid, solid, or grease-like, and silicone-based, fluorine-based, or other synthetic lubricants, Teflon fine particles, molybdenum disulfide, or the like can be used.

Further, the coating liquid can be used after being diluted with an organic solvent from the viewpoint of workability, film thickness control, etc. As such organic solvents, ketones such as methyl ethyl ketone and methyl isobutyl ketone, alcohols such as 2-propanol and nibutanol, cellosolves, acetic esters, ethers, aromatic hydrocarbons, etc. may be used alone or in appropriate mixtures. can do.

For curing after coating, methods such as active energy ray (visible light, ultraviolet rays, electron beams, X-rays, gamma rays, etc.) irradiation, heat curing, room temperature curing, etc. are used as described above.

Note that when using a curing method using visible light or ultraviolet light, a reaction initiator (photosensitizer) is used. Such a reaction initiator may be added to the coating solution. Examples of reaction initiators are 1-hydroxycyclohexylphenyl ketone, dibenzoyl.

Benzoyl, benzoin methyl ether, benzoin ethyl ether, P-chlorobenzophenone.

Examples include p-methoxybenzophenone, benzoyl peroxide, monobutyl peroxide, and camphorquinone, which can be used alone or in combination. Furthermore, 2-methyl-[4
-(methylthio)phenyl]-2-morpholino-1-
Propanone and the like can also be suitably used.

In addition, when using heat curing or room temperature curing methods,
As the polymerization initiator, peroxide compounds and amine compounds are usually used alone or in combination. Examples of peroxide compounds include benzoyl peroxide; p-chlorobenzoyl peroxide; 2,4-dichlorobenzoyl peroxide; t-butyl hydroperoxide; di-butyl peroxide; dicumyl peroxide; t-butyl peroxyacetate; t
-butyl peroxybenzoate and the like. In addition, examples of amine compounds include N, N,
-jetanol-p-toluidine; dimethyl-P-)xylene; p-)xylene; methylamine; t-butylamine; methylethylamine; diphenylamine; 4+4
'-Dinitrodiphenylamine; 0-nitroamine: p
-bromoaniline; 2.4.6-dribromoaniline, etc. can be mentioned.

An example of the composition of the components forming the back coat layer of the present invention is shown below.

(a) Phosphazene compound 100 parts by weight (with) Inorganic filler o-10 parts by weight (
C) Monofunctional monomer and/or polyfunctional monomer copolymerizable with the phosphazene compound 0 to 100 parts by weight (d)
Lubricant 0-50ii parts [(a)
~(C) based on 100 parts by weight of solid content] (e) Antistatic agent 0~10 parts by weight [(a)~(
0.05 to 5 parts by weight of organic solvent (6) photoinitiator or thermal polymerization initiator per 100 parts by weight of the solid content of C) [to 100 parts by weight of the curable compound of (a) to (C)] On the other hand, it is not necessary to use an organic solvent, but as mentioned above, from the viewpoint of workability and control of the film thickness after curing, it is preferable that the weight concentration of the mixture of (a) to (e) is 0.5. ~60%
What is necessary is to dissolve it in an organic solvent so that

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Production Example 1 Production of curable phosphazene compound (A) In a 21-volume flask, hexachlorocyclotriphosphazene (formula (NP
Clz)z cyclic compound) 86.8g was dissolved in 338g of dehydrated benzene.

310 g of pyridine and 0.23 g of hydroquinone were added to this benzene solution and stirred.

Separately, 200d of 2-hydroxyethyl methacrylate was dissolved in 237% of benzene, and this solution was added dropwise into the above flask and reacted at 60°C for 30 hours. After the reaction, pyridine hydrochloride was removed by filtration.

The filtrate was washed with water, then dried using Glauber's salt, and the solvent was removed by vacuum distillation to give a viscosity of 1.1°.3.3.5.
5-hexa(methacryloylethylenedioxy)cyclotriphosphazene CH.

(Formula (NP (0(,H,o□CC=CHz)z)s
200 g (yield: 88.3%) of a cyclic phosphazene compound represented by

Production Example 2 Production of Curable Phosphazene Compound (B) 300 d of tetrahydrofuran and 25.5 g of metallic sodium were charged into a 211-volume flask equipped with a thermometer, a stirring device, a dropping funnel, and a condenser. 2. In this reaction solution.
2.1 g (1.11 mol) of 2-trifluoroethanol was added dropwise, and after the dropwise addition, the mixture was refluxed for 3 hours to dissolve sodium 2.2-trifluoroethanol.
2.2-) Lifluoroethoxide was obtained.

Next, 198'g of hexachlorocyclotriphosphazene
(0,555 mol) dissolved in 400 d of benzene was added dropwise to the tetrahydrofuran solution containing sodium 2,2.2-1-lifluoroethoxide. Thereafter, the reaction was allowed to proceed for 4 hours under reflux.

Next, the temperature of the reaction solution was returned to room temperature, and pyridine 35
2 g (4.45 mol) were added. Further, 381 g (2.45 mol) of 2-hydroxyethyl methacrylate was gradually added dropwise from the dropping funnel, and the mixture was reacted at 60° C. for 20 hours. Next, the precipitated solid was filtered off, the solvent in the resulting filtrate was removed by vacuum distillation, and the residue was sufficiently dried to obtain 455 g of a liquid.

Preparing the coating liquid! 100 parts by weight of phosphazene compound (A) 0.5 parts by weight of silicone lubricant 2-methyl-(
4-(methylthio)phenylgo-2-morpholino-1
-Propanone 3 parts by weight Solvent: Methyl isobutyl ketone! Hyperemia-curing phosphazene compound (B) 100 parts by weight Silicone lubricant 0.2 parts by weight 2-methyl-(
4-(methylthio)phenylgo-2-morpholino-1
- Propanone 3 parts by weight Solvent: Methyl isobutyl ketone Example 1 Coating solution (a) with a solid content of 10% by weight was applied to a polyethylene terephthalate (PET) film for video (ultra-smooth surface type) using a gravure coater, and irradiated with ultraviolet rays. A back coat layer material PET film tape having a film thickness of 0.5 μm was obtained.

Various tests were conducted using this PET film tape.

Example 2 A PET film tape with a back coat layer was obtained by carrying out the same operation as in Example 1 except for using the coating liquid (b) having a solid content of 10% by weight.

Various tests were conducted using this PET film tape.

Comparative Example 1 Various tests were conducted using a video PET film tape (ultra-smooth surface type) without a back coat layer.

Comparative Example 2 Various tests were conducted using a commercially available tape as a back coat layer material.

Comparative Example 3 Various tests were conducted using a commercially available tape without a back coat layer.

The results of various tests on the film tape obtained as described above are shown in FIG. 1, FIG. 2, and Table 1.

Here, FIG. 1 shows the measurement results when the tape running speed was 1.0 cm/sec, and FIG. 2 shows the measurement results after running 1500 times.

The test method is as follows.

(1) Coefficient of friction As shown in FIG. 3, the tape 1 is run on the cylindrical drum 2, and the tension TZ in the running direction + the tension T3 in the opposite direction to the running direction. The angle θ between the running direction of the tape before and after contact with the drum was measured, and the coefficient of friction μ was calculated using the following formula.

μ=(1/θ)X j2n(T+/TI) [where i
n indicates a natural logarithm. ] (2) Abrasion resistance The weight change of the tape after running test 2000 times was measured.

(3) Dimensional change The dimensional change of the tape was measured when the temperature was changed from 25°C to 75°C.

Table I
A back coat layer is formed that has excellent durability, abrasion resistance, heat resistance, adhesion, and dimensional stability. Therefore, according to the present invention, elongation due to heat etc. is extremely small (and dimensional stability is good, the friction coefficient is small, and there is no change in the friction coefficient even after repeated use, so it has excellent running stability. The scratch resistance is thick and there is no generation of abrasion powder.

Therefore, the magnetic tape of the present invention can be effectively used as various high-grade magnetic tapes such as video and audio magnetic tapes.

[Brief explanation of the drawing]

Figures 1 and 2 are graphs showing changes in the coefficient of friction of tapes obtained in Examples and Comparative Examples, and Figure 3 is an explanatory diagram showing the method of testing the coefficient of friction conducted in Examples and Comparative Examples. It is. In FIG. 3, 1 indicates a tape and 2 indicates a cylindrical drum. Written amendment to the procedures for the hexagram filial niece (volunteer) May 23, 1989

Claims (2)

[Claims] (1) On the back of the magnetic tape, there are general formulas▲mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, a and b are a>0, b≧0, and a+b=
represents a real number satisfying 2, A represents a polymerizable curable group, and B represents a non-polymerizable curable group. ] A magnetic tape with a back coat layer, characterized in that a back coat layer is formed by curing a coating material containing a curable phosphazene compound as a main component and having a degree of polymerization of 3 or more. . (2) The curable phosphazene compound has the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, a and b are the same as above, and A is the formula CH_2=
CR^1COOR^2O-, CH_2=CR^1CONHR^2O-, CH_2=CR^1CONH-, CH_2=CR^1CR^3R^4O-, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas, There are tables, etc. ▼, (In the formula, R^1 represents hydrogen or a methyl group, R^2 represents a straight or branched alkylene group having 1 to 12 carbon atoms, and R
^3 and R^4 are each independently hydrogen or carbon number 1 to 4
represents an alkyl group. ), B represents a group represented by the formula R^5M- or ▲a mathematical formula, a chemical formula, a table, etc.▼ (wherein, M represents an oxygen atom, a sulfur atom, or an imino group,
R^5 is an alkyl group having 1 to 18 carbon atoms or 1 carbon number
~18 halogenated alkyl group, R^6~R^1
^0 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogenated alkyl group having 1 to 4 carbon atoms. ) represents a group. ] The magnetic tape with a back coat layer according to claim 1, wherein the repeating units represented by are bonded in a cyclic manner and have a degree of polymerization of 3 or more.