JPH0676271A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To ensure excellent durability and torque characteristics by using one or more kinds of ether-contg. fatty acid esters each represented by a specified formula as lubricative components. CONSTITUTION:An ether-contg. fatty acid ester having a specified structure represented by the formula is used as a lubricative component. In the formula, R<1> is 3-12C straight chain or branched chain alkyl or 2-12C straight chain or branched chain alkenyl, R<2> is 5-21C straight chain or branched chain alkyl or alkenyl, EO is oxyethylene, PO is oxypropylene, (m) is an integer of 0-18, (n) is an integer of 1-18, 1<=m+n<=18, EO and PO may bond in any order and any of random bonding and block bonding may be adopted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium excellent in durability and torque stability.

[0002]

2. Description of the Related Art Generally, a magnetic recording medium is a magnetic powder (specifically, a metal such as iron, iron oxide or chromium oxide, and its oxide) on a non-magnetic support represented by a polyester film. , Binder (specifically, polyurethane, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, etc.), organic solvent (specifically, toluene, cyclohexanone, ethyl acetate, methyl ethyl ketone, etc.) and other necessary components It is prepared by applying a magnetic paint (magnetic layer).

By the way, in a magnetic recording medium, various magnetic components are usually used for the purpose of improving surface lubricity because the magnetic layer is apt to be slidably contacted with a magnetic head, a pad, a jacket and the like during recording and reproduction and the magnetic layer is easily worn. Has been.

As such a lubricating component, higher fatty acids, higher fatty acid esters, higher fatty acid amides, liquid paraffin, waxes and the like have been proposed so far.

[0005]

However, the lubricating components proposed so far are not satisfactory in durability, running torque, stability such as starting torque, especially under high temperature or temperature / humidity cycle conditions, There is room for improvement.

[0006]

DISCLOSURE OF THE INVENTION The present inventor has a novel and useful solution for solving the above problems and proposing a magnetic recording medium which has excellent durability under a wide range of use conditions and can maintain stable torque characteristics. As a result of diligent study on lubricating components,
It was found that the intended purpose can be achieved by applying an ether-containing fatty acid ester having a specific structure,
The present invention has been completed based on these findings.

That is, the magnetic recording medium according to the present invention is characterized by using one or more ether-containing fatty acid esters represented by the general formula (1) as a lubricating component.

[0008]

[Chemical 2] [In the formula, R ¹ represents a linear or branched alkyl group having 1 to 12 carbon atoms or a linear or branched alkenyl group having 2 to 12 carbon atoms, and R ² represents 5 to 5 carbon atoms. 21 represents a linear or branched alkyl group or alkenyl group. EO represents an oxyethylene group. PO represents an oxypropylene group. m represents an integer of 0-18. n represents an integer of 1-18. m + n represents an integer of 1-18. The order of joining EO and PO does not matter. ]

The ether-containing fatty acid ester according to the present invention is a saturated or unsaturated linear or branched alcohol having 1 to 12 carbon atoms (preferably a linear saturated alcohol having 3 to 4 carbon atoms). 1 to 18 mol, preferably 1 to
About 15 mol of alkylene oxide is added, and such an adduct and a saturated or unsaturated linear or branched fatty acid having 6 to 22 carbon atoms (preferably linear saturated fatty acid having 10 to 18 carbon atoms). And a compound obtained by esterification of and according to a conventional method.

The alkylene oxide according to the present invention is propylene oxide (hereinafter abbreviated as "PO") or P.
It is a co-adduct of O and ethylene oxide (hereinafter abbreviated as "EO"). PO and EO in the co-adduct
May be a random bond or a block bond, regardless of the order of bonding.

Of these, preferred ether-containing fatty acid esters are one or more selected from propylpropylene glycol, propyldipropyleneglycol, isopropylpropyleneglycol, isopropyldipropyleneglycol, butylpropyleneglycol and butyldipropyleneglycol. Examples of the alcohol component include compounds prepared using one or more of capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid as an acid component.

The ether-containing fatty acid ester is a conventionally known lubricating component such as a hydrocarbon-based lubricating oil (liquid paraffin, α-olefin, etc.), a fatty acid ester-based lubricant (stearate-n-propyl stearate-n-). Butyl, octyl palmitate, stearyl stearate,
Ethyl oleate, dioleoyl adipate, dioleoyl phthalate, etc.), a silicone-based lubricant, a fluorine-based lubricant, or a combination of two or more thereof.

The lubricating component according to the present invention can be applied to the non-magnetic support in any form. That is,
It may be dispersed and mixed in a magnetic layer provided on one surface of the non-magnetic support, or may be used as a top coat of the magnetic layer. Further, it may be used as a back coat layer or a top coat on the back coat layer. It is also possible to apply directly to the base film surface of the non-magnetic support.

The amount of the lubricating component applied is not particularly limited as long as a predetermined effect can be obtained, and variously selected depending on the application mode. For example, when mixed and used in the magnetic layer,
Usually, 10 to 40 relative to 100 parts by weight of binder resin
Parts by weight, preferably about 15 to 35 parts by weight are applied.
If it is less than 10 parts by weight, it is difficult to obtain a predetermined lubricating effect.
If it is used in an amount of more than 0 parts by weight, bleeding out of the lubricating component to the surface of the magnetic layer becomes remarkable, which causes contamination and damage to the magnetic head and the like.

When a lubricating component is used as a top coat, it is 0.01 to 1.0 mg / m ² , preferably 0.05.
About 0.5 mg / m ² may be applied.

The magnetic recording medium according to the present invention is a film,
It can be applied to any form such as tape, sheet, disk, card and drum.

[0017]

The present invention will be described in detail below with reference to examples. The characteristics in each example were measured and evaluated by the following methods.

Preparation of Sample A predetermined lubricant is added to the following composition and kneaded with a ball mill to prepare a magnetic ink. This was applied onto a polyester film having a thickness of 75 μm so that the dry thickness would be 1.7 μm, dried, calendered, cured, punched into a disc shape, and the surface was polished to prepare a medium. .

Co-containing γ-Fe ₂ O ₃ 100 parts by weight Vinyl chloride / vinyl acetate copolymer 28 Polyurethane resin 9 Carbon black 10 Granular α-alumina 24 Stearate-n-butyl 3 Dioleyl adipate 1 Toluene 150 Methyl ethyl ketone 150

Test method [1] Cycle durability test: temperature 5 ° C./humidity 60% RH / 9 hours, temperature 25 ° C./humidity 60% RH / 3 hours, temperature 60 ° C./humidity 20% RH
/ 9 hours, temperature 25 ° C / humidity 60% RH / 3 hours cycle drive 360rp with media set
It was driven at m and a head load of 20 g / cm ² , and the time until a slide mark or peeling was recognized on the surface of the medium was measured, and evaluated in the following three stages. ◎: Very good, ○: Good, ×: Poor

[2] Durability acceleration test A drive was driven for 8 hours at 800 rpm and a head load of 30 g / cm ² , and the state of the medium surface (sliding trace, degree of peeling) at that time was observed, and the following 3 Graded. ◎: No change, ○: Sliding mark, ×: Peeling

[3] Starting Torque The torque in the state where the drive head was adhered to the medium was measured with a torque gauge and evaluated in the following three stages.
◎: Very good, ○: Good, ×: Poor

[4] Running Torque The torque required to rotate the medium (360 rpm) was measured with a torque gauge and evaluated in the following three stages.
◎: Very good, ○: Good, ×: Poor

Example 1 Durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of propyl propylene glycol myristate ester (Invention product 1) as a lubricant were evaluated. The results obtained are shown in Table 1.

Example 2 Durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of propyl propylene glycol palmitate (Invention product 2) as a lubricant were evaluated. The results obtained are shown in Table 1.

Example 3 Durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of propyl propylene glycol stearic acid ester (Invention product 3) as a lubricant were evaluated. The results obtained are shown in Table 1.

Example 4 Durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of propyldipropylene glycol myristate ester (Invention product 4) as a lubricant were evaluated. The results obtained are shown in Table 1.

Example 5 Durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of propyldipropylene glycol palmitate (Invention product 5) as a lubricant were evaluated. The results obtained are shown in Table 1.

Example 6 Durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of propyldipropylene glycol stearic acid ester (Invention product 6) as a lubricant were evaluated. The results obtained are shown in Table 1.

Example 7 The durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of butyl propylene glycol myristate ester (Invention product 7) as a lubricant were evaluated. The results obtained are shown in Table 1.

Example 8 Durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of butyl propylene glycol palmitate (Invention product 8) as a lubricant were evaluated. The results obtained are shown in Table 1.

Example 9 The durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of butyl propylene glycol stearate (Invention product 9) as a lubricant were evaluated. The results obtained are shown in Table 1.

Example 10 A magnetic ink prepared by mixing 15 parts by weight of butyldipropylene glycol myristate ester (Invention product 10) as a lubricant was evaluated for durability and torque characteristics of a medium. The results obtained are shown in Table 1.

Example 11 Durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of butyl dipropylene glycol palmitate (Invention product 11) as a lubricant were evaluated. The results obtained are shown in Table 1.

Example 12 A magnetic ink prepared by mixing 15 parts by weight of butyl dipropylene glycol stearic acid ester (Invention product 12) as a lubricant was evaluated for durability and torque characteristics of a medium. The results obtained are shown in Table 1.

Example 13 The durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of lauric acid ester of propyl propylene tetraglycol (invention product 13) as a lubricant were evaluated. The results obtained are shown in Table 1.

Example 14 3 mol of propyl alcohol PO and EO 2 as lubricants
Myristic acid ester of co-adduct with mol (Invention 1
4) The durability and torque characteristics of the media prepared using the magnetic ink prepared by mixing 15 parts by weight were evaluated.
The results obtained are shown in Table 1.

Example 15 10 moles of propyl alcohol PO as a lubricant and EO
Myristic acid ester of co-adduct with 2 mol (Invention product 1
5) The durability and torque characteristics of the media prepared using the magnetic ink prepared by mixing 15 parts by weight were evaluated.
The results obtained are shown in Table 1.

Example 16 4 mol of propyl alcohol PO and EO 2 as lubricants
Palmitate ester of co-adduct with mol (Invention product 1
6) The durability and torque characteristics of the media prepared using the magnetic ink prepared by mixing 15 parts by weight were evaluated.
The results obtained are shown in Table 1.

Example 17 Durability and torque characteristics of a medium prepared by using a magnetic ink prepared by blending 15 parts by weight of stearic acid ester of PO8 mol adduct of propyl alcohol (Invention 17) as a lubricant were evaluated. did. The results obtained are shown in Table 1.

Example 18 Myristic acid ester of a co-adduct of 8 mol of PO with 4 mol of EO of butyl alcohol as a lubricant (Invention 18)
The durability and torque characteristics of the media prepared using the magnetic ink prepared by blending 15 parts by weight were evaluated. The results obtained are shown in Table 1.

Example 19 Durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of lauric acid ester of PO6 mol adduct of butyl alcohol (invention product 19) as a lubricant were evaluated. did. The results obtained are shown in Table 1.

Example 20 Stearic acid ester of co-adduct of 6 moles of butyl alcohol with 2 moles of EO as a lubricant (Invention 20)
The durability and torque characteristics of the media prepared using the magnetic ink prepared by blending 15 parts by weight were evaluated. The results obtained are shown in Table 1.

Example 21 Myristic acid ester of a co-adduct of 6 moles of butyl alcohol with 4 moles of EO as a lubricant (Invention 21)
The durability and torque characteristics of the media prepared using the magnetic ink prepared by blending 15 parts by weight were evaluated. The results obtained are shown in Table 1.

Example 22 Durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of palmitic acid ester (inventive product 22) of 10 mol adduct of PO with butyl alcohol as a lubricant were evaluated. did. The results obtained are shown in Table 1.

Example 23 Durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of stearic acid ester of PO 10 mol adduct of butyl alcohol (invention product 23) as a lubricant were evaluated. did. The results obtained are shown in Table 1.

Comparative Example 1 The durability and torque characteristics of a medium prepared by using a magnetic ink prepared by mixing 15 parts by weight of liquid paraffin (Comparative Product 1) as a lubricant were evaluated. The results obtained are shown in Table 1.

[Table 1]

[0048]

By applying the ether-containing fatty acid ester according to the present invention as a lubricant, a magnetic recording medium having excellent durability and torque characteristics can be obtained.

Claims (1)

[Claims] 1. A magnetic recording medium comprising one or more ether-containing fatty acid esters represented by the general formula (1) as a lubricating component. [Chemical 1] [In the formula, R ¹ represents a linear or branched alkyl group having 1 to 12 carbon atoms or a linear or branched alkenyl group having 2 to 12 carbon atoms, and R ² represents 5 to 5 carbon atoms. 21 represents a linear or branched alkyl group or alkenyl group. EO represents an oxyethylene group. PO represents an oxypropylene group. m represents an integer of 0-18. n represents an integer of 1-18. m + n represents an integer of 1-18. The order of joining EO and PO does not matter. ]