JPS59121624A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To reduce errors by using a specified amount of polyurethane resin as a binder for a magnetic layer, and combining the resin with a specified amount of fluorosilicone having the structure of trifluoropropylmethylpolysiloxane as a lubricant to reduce the wear of a coated magnetic film and to prevent stripping. CONSTITUTION:Polyurethane resin is used as a binder for a magnetic layer. The most suitable amount of the resin to be used is 10-20pts.wt. per 100pts.wt. magnetic powder, and in case of <=10pts.wt., the bonding strength of the resin to a support and magnetic powder is weak. Ferrosilicone having said specified structure is combined with the polyurethane resin as a lubricant. The most suitable amount of the ferrosilicone to be used is 8-15wt% of the total amount of the binder. Powder of gamma-Fe2O3, gamma-Fe2O3 contg. Co, Fe3O4 or CrO2, ferromagnetic metallic powder of Fe, Co or Ni, magnetic alloy powder of Fe-Ni or Co-Ni, needlelike iron nitride powder or the like is used as magnetic powder.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to magnetic recording media used as magnetic tapes, floppy disks, and the like.

PRIOR ART A general magnetic recording medium has a magnetic powder such as iron oxide, vinyl chloride-vinyl acetate copolymer, acrylic resin, etc. on one or both sides of a non-magnetic support such as a polyester film.
A magnetic layer is formed by applying a magnetic paint containing a binder such as a polyurethane resin as a main component and further adding a lubricant such as a higher fatty acid, a higher fatty acid ester, or a paraffin hydrocarbon. Lubricants are added to reduce abrasion of the coating film during the movement of the magnetic recording medium against the magnetic head, and to prevent errors due to chipping, etc., but the effectiveness of this is still insufficient.

Purpose The purpose of the present invention is to provide a durable magnetic recording medium that reduces the occurrence of errors by preventing wear and chipping of the magnetic coating film by combining a specific binder with a new lubricant. The goal is to provide the following.

Structure The magnetic recording medium of the present invention is a magnetic recording medium in which a magnetic layer mainly composed of magnetic powder and a binder is provided on one or both sides of a non-magnetic support, in which a polyurethane resin is added as the binder to 100 parts by weight of the magnetic powder. Using 10 to 20 parts by weight,
In addition, fluorosilicone having a trifluoropropylmethyl polysiloxane structure is added to the binder in the magnetic layer.
It is characterized by containing ~10% by weight.

In the present invention, a polyurethane resin is used as a binder for the magnetic layer. The amount used is 10 to 100 parts by weight of magnetic powder.
The optimal amount is 20 parts by weight; if it is less than 10 parts by weight, the bonding force to the support and the magnetic powder is weak, and when used as a magnetic layer, delamination may occur during use, and the magnetic powder may easily fall off. Because of its rubber-like properties, the coefficient of friction is high and sliding with the magnetic head becomes poor.

An isocyanate compound is used in combination with the polyurethane resin as a curing agent. Other conventional binders may also be used, such as vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinylidene chloride copolymers, vinyl chloride-acrylonitrile copolymers,
Acrylic acid ester-vinylidene chloride copolymer and the like can be used in combination.

On the other hand, the fluorosilicone of said specific structure in combination with polyurethane resin is used as a lubricant. This product is easily available as a commercial product. The optimum amount to be used is 8 to 15% by weight of the total amount of the binder. If it is less than 8%, it is less effective as a lubricant, and if it is more than 15%, the strength of the coating film is reduced. It has been confirmed that this fluorosilicone has a great lubricating effect only when combined with a polyurethane resin, and that other ordinary binders such as those mentioned above have little effect.

Examples of magnetic powder include γ-Fe, o8. Co-containing γ-
Fe203°F e H04, Cr 01 or Fe
, Co, Ni, etc., or Fe-N
Magnetic alloy powder such as Co-Ni, Co-Ni, iron nitride needle powder, etc. can be used.

In addition, additives such as electrically conductive fine powders such as carzen black, graphite, and carin black graft polymers, and fine dispersants thereof may be added as antistatic agents to the magnetic layer.

To make the magnetic recording medium of the present invention, the above materials are dispersed in a solvent such as acetone, toluene, methyl ethyl ketone, or cyclohexanone to form a boron-based paint, and this is applied as a final film on a non-magnetic support such as plastic film or synthetic paper. Thickness is 2-1
The magnetic layer may be formed by coating the magnetic layer with a coating device such as a doctor blade or wire parser so that the magnetic layer has a thickness of 0μ, and drying by heating.

EffectUsing a specific amount of polyurethane resin as a binder for the magnetic layer,
Furthermore, by combining this with a specific amount of fluorosilicone having a trifluoropropylmethylpolysiloxane structure as a lubricant, abrasion resistance is improved without reducing coating film strength, and thus a durable magnetic recording medium is obtained. be able to.

Examples of the present invention are shown below. Note that both parts and percentages are based on weight.

Example 1 Iron powder (γ-F (LIQI) 100 parts, vinyl chloride-vinyl acetate copolymer (VAGH manufactured by UCC) (amount used is as shown in the table below), polyurethane resin (A3022L manufactured by Nippon Polyurethane Co., Ltd.) Reflow Fluorosilicone having a loprovir methylpolysiloxane structure (FS-1265 manufactured by Toray Silicone Co., Ltd.) (the amount used is as shown in the table below), 5 parts of Carzen Black (#45 manufactured by Mitsubishi Kasei Corporation), and an incyanate compound as a curing agent ( Coronate L (manufactured by Nippon Polyurethane Co., Ltd.) (the amount used is 10% based on the polyurethane resin) was dispersed in a pot mill for 48 hours, coated on a 75μ thick polyester film, dried and cured by heating to form a 2 to 3μ thick magnetic layer. The recording medium was then punched out to a predetermined size and polished to form a floppy disk, and its durability (number of consecutive passes on the same track) was tested.The results are shown in the table below. It is as follows.

Comparative Example A floppy disk was prepared in the same manner as in Example 1711, except that VAGH, polyurethane, and fluorosilicone were used in the amounts shown in the table below, and a durability test was conducted.

Claims (1)

[Claims] 1. A magnetic recording medium in which a magnetic layer mainly composed of magnetic powder and a binder is provided on one or both sides of a non-magnetic support, in which a polyurethane resin is used as the binder and magnetic powder 100 is used as the binder.
10 to 20 parts by weight, and the magnetic layer contains 5 to 10% by weight of fluorosilicone having a trifluoropropylmethylpolysiloxane structure based on the binder. Medium.