JPH048537Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) In general, magnetic disk jackets house magnetic disks in such a way that they can be read and recorded through a magnetic head while being rotated by an external drive. It acts as a protector from pollution. The present invention relates to a jacket for a magnetic disk, and more particularly to a jacket for a magnetic disk having a nonwoven liner material on its inner surface. (Prior art and its problems) Conventionally, the liner material for jackets for magnetic disks is a mixture of 70 to 80% by weight of viscose rayon fibers and 20 to 30% by weight of polypropylene fibers, and heat is applied between the fibers using an embossing calendar or the like. A fused non-woven fabric is used. However, since this liner material is bonded only by partially heat-sealing the polypropylene fibers, the rayon fibers tend to fall off or become fluffed, which can damage the magnetic head. In addition, since this liner material is mainly made of rayon fiber, it has high moisture absorption, and depending on the method of laminating the nonwoven fabric and jacket material, it may cause dimensional changes or wrinkles if stored or used for a long time under high temperature and high humidity conditions. It also had the disadvantage of causing the occurrence of In other words, dimensional changes in the liner material cause the jacket to wave or warp, impeding smooth rotation of the disk. Furthermore, this type of liner material absorbs the lubricating oil that is pre-adhered to the surface of the magnetic disk when the disk rotates, resulting in discoloration of the liner material, reduced durability, and damage to the disk. In some cases, smooth rotation was impaired. Therefore, in order to eliminate the drawbacks of the conventional liner materials mainly made of viscose rayon, the present inventors investigated various non-woven liner materials mainly made of synthetic fibers, but none of them except polyester fibers have a high static electricity resistance. It was not preferable as a liner material because it was easy to cause peeling and pilling. However, this nonwoven fabric mainly composed of polyester fibers also has the disadvantage of poor cutting properties, in which the fibers around the openings are not completely cut when punching out the openings. As a result, the fluff remains and tends to damage the magnetic head and magnetic disk when the disk rotates, and abnormal friction with the disk sometimes causes uneven recording and reproduction. (Purpose of the invention) The present invention has been made to solve the above-mentioned drawbacks of the prior art, and provides a jacket for magnetic disks equipped with a nonwoven liner material that has good cutting properties and does not cause fuzzing, fiber shedding, or dimensional deformation. The purpose is to obtain. (Structure and operation of the invention) The invention is made by partially bonding the fibers of a web made of polyester fibers having a simple fiber strength of 1.0 to 4.5 g/d by heat fusion, and has an apparent density of 0.1.
This jacket for a disk is characterized in that a nonwoven liner material of ~0.3 g/cm ³ is adhered to the inner surface of a synthetic resin jacket material. The magnetic disk jacket of the present invention is manufactured based on a developed view as shown in FIG. 1, for example. That is, the jacket for a magnetic disk of the present invention is made by pasting a nonwoven fabric liner material 3 on the inner surface of a jacket material 2 made of synthetic resin such as vinyl chloride or ABS resin using a heated embossing roll, a heated flat plate, etc., and forming a magnetic disk as shown by dotted lines. Openings such as the center hole 5, head window 6, index hole 7, etc. are punched out corresponding to the insertion position of the non-woven fabric liner material 3.
A- shown in Figure 1 with the pasted side inside.
It is made by folding along the A' line, then folding in the peripheral adhesive part 8 and gluing it into a bag shape. The resulting magnetic disk jacket 1 has a cross-sectional view as shown in FIG. The nonwoven fabric liner material 3 used in this invention is 1.0~
The fibers of a web made of polyester fibers having a single fiber strength of 4.5 g/d are partially bonded by heat fusion. Conventionally, commonly used polyester fibers have a single fiber strength of approximately 4.7 g/d or more when measured under standard conditions, but the single fiber strength is 4.5 g/d.
If it exceeds this value, the rigidity will be high and the blade shape will be easily damaged during punching, so the fibers will not be completely cut and fluff will easily appear. On the other hand, if it is less than 1.0 g/d, the wear of the liner material will increase due to friction with the disk, and the life of the liner material will be shortened, which is not preferable. Therefore, in the present invention, the single fiber strength of the polyester fiber is 1.0 to 4.5 g/d, preferably 1.0 to 3.5 g/d.
g/d is used. Note that synthetic fibers other than polyester fibers, such as polyamide fibers and acrylic fibers, have problems such as generation of static electricity and pilling, and viscose rayon fibers have poor moisture resistance and durability. It is not recommended for use in The nonwoven liner material 3 used in the present invention is obtained by forming the polyester fibers into a web using a web forming method such as a carding method, an airlay method, or a wet method.
It can be obtained by performing partial heat fusion using an embossing calender or the like having a pattern in which predetermined shapes such as dots, lines, circles, squares, etc. are distributed at constant or appropriate intervals. The bonded portion by heat fusion is in the form of a film, and cleaning of dust and the like is performed at the convex portion, which is the non-bonded portion.
Therefore, it is preferable that the area of this bonded portion occupies 10 to 35% of the web area; if it is less than 10%, sufficient bonding strength will not be obtained, and fibers will easily come off and fuzz will occur, while if it exceeds 35%, the web will become stiff. As the cushioning properties are lost, the cleaning effect is also reduced. The area of the bonding portion is particularly preferably 20 to 30%. Note that if the fibers are heated without pressure before being heat-pressed using an embossing calender or the like to loosely bond the intersections of the fibers, fiber shedding and fluffing will no longer occur, and a better nonwoven fabric liner material can be obtained. The apparent density of the nonwoven liner material 3 obtained by the above procedure must be 0.1 to 0.3 g/cm ³ . This is because if the apparent density is less than 0.1 g/cm ³ , the required strength of the liner material cannot be obtained, and if it exceeds 0.3 g/cm ³ , the liner material becomes too hard and may damage the media. The fabric weight of the nonwoven liner material 3 of the present invention is 20 to 50.
g/ ^m2 is good, preferably 25-40g/ ^m2 ,
The thickness is preferably 0.15 to 0.35 mm, preferably 0.2 to 0.35 mm.
0.3mm is good. When the nonwoven fabric liner material 3 used in the present invention is attached to the jacket material 2 by fusion processing, it can be easily embedded because the single fiber strength of the polyester fiber is low, and it can be processed at a low fusion temperature. Therefore, the jacket will not be deformed by heating during adhesion. In addition, in the punching process after pasting, the liner material 3 of the present invention uses polyester fibers with low single fiber strength, so there is no damage to the blade shape, good cutting performance, and no fuzz generation due to cutting. rare. Furthermore,
Since the fibers constituting the liner material 3 are welded at the joint, the fibers will not fall off during cutting. In this way, the nonwoven fabric liner material 3 used in the present invention
has good cutting properties, no fuzzing, no fiber shedding, no dimensional deformation, and the disk can be rotated very smoothly. Therefore, the torque generated between the disk and the liner material when the disk is rotated is also smaller and better than in the conventional case. (Example) Example A web of 100% polyester fiber of 1.5d/51 (single fiber strength 1.5g/d) was made, and the temperature
A nonwoven fabric with a bonding area of 25% was formed through an embossing calender at 220°C and a linear pressure of 40 kg/cm. This nonwoven fabric has a basis weight of 35g/ ^m2 and an apparent density of 0.14g/m2.
It was warm at ^cm3 . This nonwoven fabric was heat-sealed as a liner material to a jacket material made of vinyl chloride resin at 160 to 180°C, and openings etc. were punched out and formed into a jacket. This jacket had excellent cutting properties, with no damage to the blade shape during punching, and the fibers at the periphery of the opening were completely cut, leaving no fuzz at all. Therefore, no trouble occurred during use of the magnetic tape. Also, the temperature is 55℃ and the humidity is 95%.
Under these conditions, the dimensional change in the liner material was small, within ±0.5%, and no migration of lubricating oil to the liner material was observed. Furthermore, the torque between the disk and the liner material was small and good, as shown in Table 1. Comparative example: 75% rayon fiber of 1.5d/51mm,
A nonwoven fabric was made to form a jacket under the same conditions as in the example except that a web consisting of 25% polypropylene fibers of 1.5 d/51 mm was used. Although this jacket had good cutting properties, the dimensional change in the liner material was as large as ±10%, migration of lubricating oil to the liner material was observed, and the torque between the disk and the liner material was large.

[Table] The torque between the disc and liner material is
This is a value measured using a HEIDON-14TT torque type friction resistance measuring machine (manufactured by Shinto Kagaku Co., Ltd.). (Effects of the invention) As mentioned above, the magnetic disk jacket of the present invention has good cutting properties and is equipped with a non-woven liner material that does not shed fluff or fibers, so it will prevent damage to the magnetic head during use of the magnetic disk. No large loads are generated due to friction. Furthermore, the liner material used has good dimensional stability and does not absorb lubricating oil on the disk, ensuring smooth rotation of the disk. Therefore, the magnetic disk jacket of the present invention hardly causes troubles such as damage to the magnetic disk or magnetic head or increase in torque even when used for a long period of time, and is extremely practical with excellent cleaning performance and durability. It's expensive.

[Brief explanation of the drawing]

FIG. 1 is a developed view showing an example of the jacket for a magnetic disk of the present invention, and FIG. 2 is a sectional view of the jacket for a magnetic disk of the present invention housing a magnetic disk. 1...Jacket for magnetic disk, 2...Synthetic resin jacket material, 3...Nonwoven fabric liner material, 4...Magnetic disk.

Claims (1)

[Scope of utility model registration request] An apparent density of 0.1 to 0.3 g/cm ³ made by partially bonding the fibers of a web made of polyester fibers with a single fiber strength of 1.0 to 4.5 g/d by heat fusion.
A jacket for a magnetic disk, characterized in that a non-woven liner material of 100% is adhered to the inner surface of a jacket material made of synthetic resin.