JPS6074120A - Magnetic recording medium having primer coating layer - Google Patents

Abstract

PURPOSE:To improve durability by incorporating a lubricating agent which is liquid at a room temp. into a primer coating layer. CONSTITUTION:A magnetic layer is constituted of a magnetic material, polymer binder, lubricating agent and other additives. The polymer used for the primer coating layer is enumerated by, for example, polyurethane of the like having good adhesion to a base body and the polymer having a three-dimensional crosslinking structure is preferred. The polymer which itself becomes three-dimensional, for example, an epoxy resin or the like is used. A lubricating agent which is liquid at a room temp. is required to be incorporated into such primer coating layer. The amt. of such lubricating agent is preferably in a 0.1-30wt% range of the primer coating layer. Materials generally used as a lubricating agent are enumerated in addition to long chain fatty acid ester as represented by, for example, butoxyethyl myristate or the like as such lubricating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording medium having an undercoat layer, and more particularly to a magnetic recording medium having increased durability by containing a lubricant in the undercoat layer. Rir.

Prior Art As one of the means for improving the adhesion between the magnetic layer and the substrate of a magnetic recording medium, for example, a tomEη consisting of vinyl chloride-acrylic L combined with 1 to Ryl Jtm is provided between the substrate and the magnetic layer. However, simply increasing the adhesive strength with such an undercoat layer cannot sufficiently improve the durability of the magnetic layer. 1゛1゛magnetic↑,'L
There is a tendency for the thickness of tM to become wider. As the magnetic layer ages, its durability deteriorates, making improving durability a serious issue.

Purpose of Defense The present invention has been made with these points in mind, has been carefully considered, and has reached the purpose of (a) (more durable trot).
1. Constitution and Effects of the Invention To provide a magnetic recording medium (;?)
41 Magnetic recording medium with undercoat waste formed between IQ layers [
A magnetic recording medium characterized by containing an air-temperature liquid d1'' agent in the undercoat layer,
is achieved.

Welcome to the present invention! The bamboo layer is made up of magnetic materials, polymer binders, lubricants, and other additives. In particular, the lubricant is present at the interface between the magnetic layer and the head.
It plays a role in protecting wounds.

It is important to maintain durability that a suitable amount of lubricant exists at the interface for a long period of time. However, as the thickness of the magnetic layer is made thinner, it becomes more difficult to properly interpose the lubricant across the interface. This problem can be improved according to the present invention. As the magnetic fiber, polymer binder, crushing agent, and other additive materials, conventionally known and used materials can be used.

The present invention also includes a substrate 1. , l, non-magnetic thermophilic! yI+'1 resin, such as polyJ-ethylene terephthalate-1-, poly]-ethylene2,6-naphthalene-1-
A film made of polyester stellate can be used.

Such a substrate does not necessarily have good adhesion to the magnetic f1 layer, and due to poor adhesion, often has poor durability, but such a substrate can also be used in the present invention.

Traditional magnetic recording IA! Those which are used as a substrate in the body are too preferably used.

In this defense, the polymer used for the undercoat layer is as follows:
For example, polyurethane, polysprue, polyvinyl chloride, polyvinylidene chloride, butane 1-acryloni 1-
4Tb with good adhesion to substrates such as rill rubber, epoxy, etc.
The following can be mentioned. Furthermore, the effects of the present invention can be made even more effective by using copolymer modified products or mixtures of two or more of these polymers. (Three-dimensional cross-linked structure) (3-dimensional cross-linked structure) For example, porin itself becomes three-dimensional, such as 1-boly resin, unsaturated poly-1-ster resin, butadiene, etc. It is preferable to use rubber-based resins, polyurethane resins, etc. represented by . Also, linear poly7- has three-dimensional expression <f
Monoter, Aligo 7-, and a chain polyester with which a polymer is added and no crosslinking reaction occurs. - J, 1! In order to make it three-dimensional, for example, it can be obtained by mixing polyfunctional acrylate 1 to soluble nylon and subjecting the polyfunctional acrylate 1 to radionol polymerization. This is an example of a subbing layer.

In the present invention, it is necessary to avoid containing a liquid lubricant under air temperature in the undercoat. The amount of such lubricant is preferably in the range of 0.1 to 30% by weight of the undercoat layer. Such lubricants include, for example, long-chain fatty acids such as butoxyedylmylis 7'-1 and 2-alhexylstearate 1-[stel, 1-limedi].
Polyfunctional long-chain fatty acid esters such as pan-1-ly-A-leate; long-chain fatty acids such as oleic acid, etc.
f711 force MQ: dimethylsilicone oil; silicone oil represented by Kirin; fluorine-based lubricants: mineral oil, α-A-refin A oligomer 1n-paraffin, animal oil; vegetable oil, etc. Generally lubricating agents Examples include those used as agents.

A lubricant that is solid at room temperature (a-rb mixture) or a lubricant that is liquid at room temperature can be suitably used.

If the lubricant content is too high, the lifting platform undercoat will cause softening, which is undesirable. Also, if it is too small, the effect will be small.

Furthermore, it is effective to add 0.5 to 10,000 M% by weight. The thickness of the undercoat layer is 0.1 μ~E) ti /
It's good. In the undercoat layer, add inorganic powder such as J-bon black, calcium carbonate, etc., or powder of α-iron oxide, alumina, titanium oxide, etc. of the same hardness. . These F coating layers are applied as a solution or paint to the base film 11, dried, and if necessary crosslinked (for example, heat treatment, ultraviolet treatment, electron beam treatment, etc.) to form a uniform coating 11 T i "fl is formed by forming 'A'. The coating a1j)dl can be performed using a conventionally well-known method, for example, a 1-router method.

In the magnetic recording medium of the present invention, the magnetic layer has a 19 force of 633 μm.
It is especially effective on items that are less than 1 meter thick.

Example.

Next, examples of the present invention will be described. In the Examples and Comparative Examples below, ``1 part'' is referred to as ``C``heavy goods''.

Example 1 Undercoat layer: polyurethane resin 707ift polyisocyanate (-) 5 parts crosslinking agent lubricant Δ
Leaves oil 5 parts MiBK, 1~Remer.

A composition consisting of cyclohequilinone mixed solvent 200a++ was mixed and dispersed and applied to both sides of a 75 μm polyvinyl film to a dry thickness of about 1 μm, and allowed to dry.

Next, between the magnetic layers, 70 parts of γ-1~0203, 1 part of polyurethane, 1 part of lastomer, and 7 parts of water, 17 parts of vinyl chloride-acetate di-nylated polymer, 17 parts of carbon black, 5 parts of dispersant, and 2 parts of polyisocyanate. Crosslinking agent 21'ill Te1
～Rahydrofuran, Schiff] 1-phosphorus mixed solvent 1
80 parts lubricant nib (dry a composition consisting of 1.5 parts of xyedylsteare 1-1, 5 parts of olive delta oil on both sides of the undercoat layer) "I"
! II: Coat to a thickness of approximately 1 μm, dry, calender both surfaces, crosslink by heating, punch out a +11 number shape, and hold a Kotsupie disk.

Example 2 In Example 1, 1/1 part of 2-1 Dillhexyl Sderley and A
A floppy disk was prepared in the same manner as in Example 1 using 1121 parts of Rain 1.

Comparative Example 1゜Example 1
Eye +11:'i l.

In addition to being directly installed on both sides of the polyester film substrate (, (
C1] 1. Same as Example 1. ] Tsutu-1゛chair 1
! 11C9 Comparative Example 2 A ζ floppy disk was obtained in the same manner as in Example 1 except that the undercoat layer did not contain a lubricant.

The strength value of the durability of the floppy disks of each Example and Comparative Example produced in this way by CfA was evaluated using a 5.25-inch commercially available floppy disk device a as described below. When the same track C'' is continuously rotated under head load, the durability of the medium is increased when the output level of C1 becomes 0% or less.The ambient temperature is 50 degrees.

Table 1 shows the durability evaluation results obtained in the above Examples and Comparative Examples.

Table 1 Procedural amendment document (Showa year 2017/) month - 1 day 1 Patent application for indication of the case Showa 58-179243 3 2 Name of the invention Magnetic recording medium with dot coating layer 3 Relationship with the famous case to be amended Patent applicant 1-1'1ffi11, Minamihonmachi, Higashi-ku, Osaka (300)
Representative of Teijin Ltd. Okamoto Sashibe 5 Target of amendment 6 Contents of amendment □゛gu-ichiri (+1 Details ■ In the 13th line of page 3, [formerly known as cumulative month] and ne, ro are changed to " Traditionally known as a base ingredient,
Correct to 1.

(2) Page 3, line 19, K “Karu base” is 1
Such a substrate is ground down.

(3) On page 4, line 8, the text "Epoxy, etc. J" is corrected to "1 Epoxy, etc."

(41fi) On page 4, line 18, "Konoshii." is corrected to "preferable."

(5) On page 4, line 18, it says, ``Monoter 1.''
Monomer JKU Correction (6) On page 4, No. 19-1, the words ``Kasesemi-1'' are corrected to ``Kasesase, Mi''.

(7) On page 5, line 8, 1.1, it says ``Ether-1'', but ``l'' stops at ``ethyl''.

(8) On page 5, line 15 of the same page, there is “carbon hydrogen” [
Hydrocarbon, [Correct to.

(9) On page 5, line 16, the phrase ``oil; etc.'' has been corrected to ``oil, etc.''

(10) On page 6, line 8, "Silicon 1, etc. - 1" should be revised to "Silicon, etc. 1."

θ1) On page 6, line 10 of the same page, it says "ten no 0 cloth".
-NJ correction to Hihe application-1.

0ri On page 7, line 7, it says, ``It's called alurgo [-corrected to alcoholo.

餞 On page 7, line 10 of the same page, ``To 1 no Oh no Sea 1 to Tameru is ``)・ノL all'' V different type.

04) In the 3rd month of the 8th saga, ``The word ``Nkurohexane J'' is revised to ``Nkurohexane J''.

09 In the 8th line of page 8, “1 and jh i) on both sides [
IK correction on both sides (1 (e lr+) r -7' y on page 9, line 7
, ri+1i+ku19-1 [Disc side Iku+! l , correct fjl to 1.

(], -]d

Claims (1)

[Scope of Claims] 1. A magnetic recording medium having an undercoat layer formed between a substrate and a magnetic layer, characterized in that the undercoat layer contains a liquid lubricant under air temperature. 2. The magnetic recording medium according to claim 1, wherein the undercoat layer is three-dimensionally crosslinked. 3. Claim 1 or 2, characterized in that the lubricant is in the range of 0.1 to 30% by weight of the undercoat layer.
Magnetic recording medium described in Section 1.