JP2019104221A - Antimagnetic case - Google Patents

Abstract

To provide an antimagnetic case of low cost and excellent workability, which prevents magnetic information on a stored magnetic recording medium from disappearing thanks to the external magnetic field of the magnet having a magnetic flux of 140 mT.SOLUTION: The antimagnetic case 1 is comprised at least of: two rectangular-shaped cover parts 2, 3 that contain magnetic shield boards due to the composite resin skin; a bending part that connects one side each of the covers; storage parts 5a, 5b provided on the surfaces of the skin inside the cover parts. The magnetic shield board is a laminated body comprised of a soft magnetic steel plate and a composite resin foaming sheet, and the face on the side of the soft magnetic steel plate is positioned so as to face the surface of the skin inside the cover. The thickness of the soft magnetic steel plate is 0.25 mm to 0.55 mm, and the total of the thickness of the composite resin foaming sheet and the skin of the outer side of the cover is 2.30 mm or over, and the thicknesses of the outer side of the cover and the skin inside the cover are each 0.30 mm or over. The total of the 10 times multiplication of the thickness of the soft magnetic steel plate, the thickness of the composite resin foaming sheet, and the skin of the outer side of the cover part is 7.80 mm or over.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a case for storing a passbook having a magnetic recording unit, a magnetic card, and the like, and particularly relates to a magnetic shielding case useful for protecting magnetic information of the magnetic recording unit.

  At present, magnetic recording media such as passbooks having a magnetic recording portion such as a magnetic stripe and magnetic cards such as a credit card and a cash card are widely and generally used. Various information is recorded as magnetic information in the magnetic recording part of such a magnetic recording medium. However, when the magnetic information is exposed to a strong magnetic field, the magnetic information disappears and it is possible to use ATM or the like. It is known that the magnetic information can not be read, and a magnetic stripe having a high coercive force of 4000 Oe or 2750 Oe, which is called Hi-Co, is used as a passbook so that the magnetic information does not disappear easily now. Although it has come to be widely used for magnetic cards, passbooks and magnetic cards that use magnetic stripes with low coercivity of 650 Oe and 300 Oe, which are conventionally used called Lo-Co, are also used in magnetic read / write systems. It is the fact that it is still used in large numbers due to the cost of updating and the like.

  On the other hand, in our living environment, the types and usage of magnets that generate magnetic fields are diversified. In recent years, although small in size, such as rare earth magnets are used for speakers and vibrators of mobile phones, etc. Also, magnets that generate strong magnetic fields are being used for fasteners of mobile phone cases and the like. Under such a living environment, opportunities for the magnet to come close to the magnetic stripe of the passbook or the magnetic card are increasing, and among the Lo-Co magnetic stripes, a passbook using the magnetic stripe of 300 Oe having a particularly low coercive force, etc. In recent years, problems such as the disappearance of the magnetic information of the magnetic field have become frequent.

  In order to solve the problems as described above, for example, Patent Document 1 discloses a magnetic material formed by laminating a steel foil of 0.03 mm to 0.20 mm in thickness made of permalloy which is a high magnetic permeability material and a soft plastic material or the like. Shield materials etc. have been proposed, and it is described that if the magnetic shield material is used, it is possible to obtain a card case which has sufficient magnetic shielding properties, is light and is flexible and has a soft touch and a soft touch. There is.

  In addition, according to Patent Document 2, a rectangle having a thickness of 0.3 mm or less, in which paper is pasted on both sides of a high permeability material of about 0.05 mm for protecting data of the magnetic recording part of the passbook in the passbook case. A magnetic shielding case for a passbook is proposed, which is characterized in that a magnetic shielding material consisting of a plate-like plate material is accommodated, and it is possible to attenuate the magnetic flux density of 40 mT to 20 mT by the magnetic shielding material. It is described that it is possible to prevent the data in the magnetic recording part from being destroyed by the magnet of the speaker part.

  However, although the permalloy steel foil used for the magnetic shield material shown by patent document 1 has very good magnetic shielding performance compared with other metal foil etc., its price is very expensive and its workability is also The difficult point is a problem, and furthermore, it is not described at all about how much thickness there is and how much the magnetic shielding performance is.

  In addition, when a passbook case as shown in Patent Document 2 is used, the magnetic field of the magnetic flux density around the speaker magnet incorporated in the mobile phone is very excellent in the magnetic shielding effect against an external magnetic field of about 40 mT. The demagnetizing effect against an external magnetic field by a magnet having a relatively high surface magnetic flux density, such as 100 to 140 mT, of the surface commonly used for a clasp is not sufficient. Also, it is only described that it uses a magnetic shielding material consisting of a rectangular plate material of 0.3 mm or less constructed by laminating paper on both sides of a high permeability material of about 0.05 mm to obtain magnetic shielding performance. There is no description about what the magnetic material is specifically, and further, a specific description on the distance between the magnetic stripe and the magnetic shielding material, the thickness of the passbook case, etc., which is essentially important information to improve the magnetic barrier performance. Was not seen.

Japanese Utility Model Showa 62-124899 True No. 3128850

  The present invention has been made in view of such a situation, has low cost and is excellent in processability, and magnetic information of a magnetic recording medium housed in a magnetic shielding case by an external magnetic field by a magnet having a surface magnetic flux density of 140 mT. The purpose is to provide a magnetic shielding case that does not disappear.

  In order to solve the problems of the present invention, as a result of investigations by the present inventor, two rectangular pieces of a cover including a magnetic shield plate by a synthetic resin skin and a bending part and a cover connecting one side of each cover A magnetic shielding case comprising at least a storage section provided on an inner surface of a skin and storing a magnetic recording medium such as a passbook having a magnetic recording section or a magnetic card in the storage section and sandwiching it by a cover section, The magnetic shield plate is a laminate of a soft magnetic steel plate having a thickness of 0.25 mm or more and 0.55 mm or less and a synthetic resin foam sheet, and the surface of the magnetic shield plate on the soft magnetic steel plate side is facing the cover inner surface It came to invent the magnetic shielding case arrange | positioned at. By using a soft magnetic steel plate with a thickness of 0.25 mm or more and 0.55 mm or less as the high magnetic permeability material used for the magnetic shield plate of the magnetic shield sheet, it is possible to provide a magnetic shield case excellent in processability at low cost. I understand.

Furthermore, as a result of the inventor's investigation, the thickness of the soft magnetic steel sheet used for the magnetic shielding case is Amm, the thickness of the synthetic resin foam sheet is Bmm, the thickness of the cover outer skin is Cmm, and the thickness of the cover inner skin is Dmm. When it did, it came to invent a magnetic-shielding case which satisfied the following relational expression (1)-(5).
By limiting the thickness of each component of the magnetic shielding sheet as described above, the influence of the external magnetic field can be effectively reduced by securing an appropriate distance between the external magnetic field and the magnetic recording medium, and additionally, high permeability can be achieved. By selecting the appropriate thickness of the magnetic material, the influence of the external magnetic field can be further reduced, and as a result, the magnetic recording medium housed in the magnetic shielding case becomes an external magnetic field due to the magnet having a surface magnetic flux density of 140 mT. It became possible to optimize the design of the magnetic shield sheet so that the magnetic information recorded in the magnetic recording part of the magnetic recording medium would not disappear even if exposed.

  When the magnetic shielding case of the present invention is used, the magnetic information recorded in the magnetic recording portion of the magnetic recording medium stored in the magnetic shielding case by the external magnetic field by the magnet having a surface magnetic flux density of 140 mT is excellent in processability at low cost. The magnetic information can not be read because the data does not disappear.

The magnetic card is accommodated in the storage part of the magnetic shielding case of this invention, and the typical top view which shows an example of embodiment when the state which open | released the magnetic shielding case is seen from the inner surface of a magnetic shielding case. The typical top view which shows an example of embodiment when the magnetic-shielding case of this invention shown in FIG. 1 is seen from the outer surface of a magnetic-shielding case. The magnetic card is stored in the storage part of the magnetic shielding case of this invention, typical sectional drawing which shows an example of embodiment of the state which closed the magnetic shielding case and pinched | interposed the magnetic card by the cover part. The magnetic card is stored in the storage part of the magnetic shielding case of this invention, typical sectional drawing which shows an example of embodiment of the state which closed the magnetic shielding case and pinched | interposed the magnetic card by the cover part. A schematic view showing an example of the external dimensions and positional relationship of the housing portion, the magnetic shield plate, and the cover inner skin when the magnetic shield case of the present invention is opened from the inner side of the magnetic case Plan view. The magnetic card is stored in the storage part of the magnetic shielding case used for the Example of this invention, and in order to perform the evaluation test of a magnetic shielding performance, the magnetic shielding case is closed and the typical sectional view which shows the state which clamped the magnetic card by the cover part.

  The details of the magnetic shielding case of the present invention will be described with reference to the drawings.

<< Magnetic shielding case >>
The magnetic shielding case 1 of the present invention, as shown in FIGS. 1 to 4, has a rectangular strip cover 2 including a magnetic shielding plate (10a, 10b) by synthetic resin skins (2a, 2b, 3a, 3b) Magnetic recording medium (magnetic card 6) having a cover portion 3 and a bending portion 4 connecting one side of each cover portion and a magnetic recording portion (magnetic stripe 7) provided on the surface of the cover inner surface (2a, 3a) The magnetic shielding case is a double-sided magnetic shielding case comprising at least a housing (5a, 5b) for housing the magnetic recording medium in a state where the magnetic recording medium is stored in the housing as shown in FIG. 3 or FIG. The magnetic recording medium is used by being folded along the folding line 8 so that the magnetic recording medium is nipped by the respective cover parts.

  Although the magnetic shielding case shown in FIG. 1 connects the long sides of the cover portion by the bending portion, the present invention is not limited to this, and the short side may be connected according to the intended use and usage. Moreover, although only one storage part is provided on each cover inner skin surface in FIG. 1, the present invention is not limited thereto, and a plurality of storage parts may be provided in parallel on one cover inner skin surface. Alternatively, the storage portion may be provided in multiple layers. The external dimensions of the magnetic shielding case are not particularly limited, and usually the magnetic recording media such as passbook and magnetic card can be stored, and the external dimensions of the cover of the magnetic shielding case are larger than the magnetic recording media stored. It is sufficient that the entire recording unit be firmly covered by the magnetic shield plate included in the cover of the magnetic shield case.

  The method of producing the magnetic shielding case of the present invention is not particularly limited, and as shown in FIG. 3, the front cover and outer cover are made to face each other, and each cover is welded and joined by welding or the like. And the bent portion may be integrally formed, or as shown in FIG. 4, the cover portion and the bent portion are separately formed, and then the cover portion and the bent portion are welded and joined by a method such as welding. It may be created by unifying the cover portion and the bending portion. In the present invention, there is no particular limitation on the method of joining the cover portion and the bent portion or the method of partially joining the cover portions to each other, a method using various adhesives, a method by sewing, a method by heat sealing, ultrasonic wave A method suitable for a raw material such as a skin material to be joined may be appropriately selected from a method by welding, a method by high frequency welding, and the like.

<Cover part>
The cover of the magnetic shielding case of the present invention has a rectangular piece-like appearance by enclosing the magnetic shielding plate with a synthetic resin skin, and is a storage that can accommodate at least one or more magnetic recording media on the inner skin surface of the cover. It is characterized by having a department. In the present invention, the role of the cover of the magnetic shielding case is to securely cover the magnetic recording part of the magnetic recording medium stored in the storage part with the magnetic shielding plate contained in the cover part, and to record the magnetic recording recorded in the magnetic recording part by the external magnetic field. It is to prevent the information from being erased, so that the cover has an outer dimension at least larger than that of the stored magnetic recording medium, and further, a magnetic shield plate of substantially the same size as the outer dimension of the cover. By including it, it is possible to securely protect the magnetic information recorded in the magnetic recording part of the magnetic recording medium stored in the storage part of the magnetic shielding case from the influence of the external magnetic field. Therefore, the outer dimensions of the cover in particular are not limited, and may be appropriately designed within the scope not departing from the object according to the type and usage of the magnetic recording medium to be stored.

  With regard to the total thickness of the cover part, the thinner the cover, the easier it is to handle the shield case, while the lower the shield performance, and the thicker the cover tends to improve the shield performance of the shield case, but the handling tends to be difficult. The demagnetization performance of the demagnetization case is not simply determined by the total thickness of the cover, but the thickness of the soft magnetic steel sheet used for the demagnetization plate enclosed in the cover, the thickness of the synthetic resin foam sheet, and the thickness of the cover Because the thickness of each skin and the like affect in combination, it is not possible to uniquely limit only the range of the total thickness of the cover of the present invention. As a result of the present inventor's investigation, when the thickness of the soft magnetic steel sheet is 0.55 mm, the thickness of the synthetic resin foam sheet is 3.00 mm, and the thickness of each skin of the cover is 0.30 mm, It has been confirmed that the lower limit of the total thickness can be reduced to about 3.15 mm, but the lower limit is not limited to this. Conversely, the upper limit of the thickness of the cover is not particularly limited as well as the lower limit, but the upper limit of the thickness of the cover is preferably 8.00 mm or less, considering only the handling of the magnetic shielding case, and 7.00 mm The following is more preferable, and 5.00 mm or less is the most preferable. In any case, it is clear that it is preferable to make the thickness of the cover as thin as possible while securely satisfying the magnetic shielding performance of the magnetic shielding case.

(Skin on the cover)
The synthetic resin used as the main raw material of the cover surface skin of the magnetic shielding case of the present invention is not particularly limited, but the synthetic resin skin used in the present invention is basically a sheet of synthetic resin very thin by heat rolls and the like. It is preferable to use thermoplastic synthetic resin as the main raw material, for example, polyvinyl chloride resin, since it is assumed that various parts are joined by various welding processing and heat sealing processing after die-cut products processed into And thermoplastic polyurethane resins, polyolefin copolymer resins mainly composed of polyolefins, acrylic resins, polyester resins, polyamide resins and the like may be suitably selected and used, and polyvinyl chloride resin is most preferable. It is preferable to use as a main raw material of the cover part skin of a magnetic-shielding case. The synthetic resin sheet as described above is usually a low magnetic permeability material having a maximum relative permeability of about 1 or less.

  Regarding the thickness of the cover of the cover, it is preferable that the thicknesses of the cover inner and outer covers be both 0.30 mm or more, and more preferably 0.40 mm or more. When the thickness of each cover of the cover is less than the above lower limit, there are problems in handling at the time of processing such as easy entry of wrinkles and easy opening of holes when performing various welding processes, and lack of strength. When used as a magnetic shielding case, there are many problems of durability at the time of use, such as easy formation of holes. The upper limit of the thickness of the cover is not particularly limited, but the thickness of both the cover inner and outer cover is preferably 1.00 mm or less, and more preferably 0.80 mm or less. . If the thickness of each cover of the cover exceeds the above upper limit value, the energy required for various welding processes and heat sealing processes becomes too large, which tends to cause a problem that the skins are not welded and joined well.

(Magnetic shield plate)
The magnetic shielding plate contained in the synthetic resin skin of the cover of the magnetic shielding case of the present invention has a role of protecting the magnetic information recorded in the magnetic recording portion of the magnetic recording medium stored in the magnetic shielding case from the external magnetic field. ing. The magnetic shield is laminated between the cover inner skin and cover outer skin having a larger outside dimension than the magnetic shield in a state where the entire magnetic shield is completely covered by the cover outer cover, as shown in FIG. As shown in the hatched portion of 13a, the cover plates of the outer periphery of the slightly outside magnetic shield plate are welded and joined together by welding or the like so as to surround the magnetic shield plate and contained at a predetermined position in the cover portion and fixed. Be done. The magnetic shielding plate of the present invention is a laminate of a soft magnetic steel plate which is a high magnetic permeability material and a synthetic resin foam sheet which is a low magnetic permeability material as illustrated in FIG. 3, and the soft magnetic steel plate and the synthetic resin The interlayer of the foam sheet is not particularly limited, but it is preferable that the foam sheet be adhered with an adhesive or a double-sided tape.

  The outer dimensions and the shape of the magnetic shield of the present invention are not particularly limited, as long as at least the magnetic recording portion of the magnetic recording medium housed in the magnetic shielding case can be concealed. However, basically, it is preferable that the outer dimensions of the magnetic recording medium housed in the housing portion of the magnetic shielding case be such that the entire outer diameter of the magnetic recording medium can be concealed. It is preferable that a magnetic shield plate having an outer dimension slightly smaller than the dimension is included in the cover.

  As a method of protecting the magnetic information recorded in the magnetic recording portion of the magnetic recording medium from an external magnetic field generated from a magnet or the like in general, a magnetic flux affecting the magnetic recording portion by spacing the magnetic pole of the magnet from the magnetic recording portion. There is a method to reduce the amount of wire, and another method is to arrange the magnetic flux line with high permeability by arranging a plate made of high permeability material or the like to easily pass the magnetic flux line between the magnetic pole of the magnet and the magnetic recording portion. One way is to reduce the number of flux lines that affect the opposite magnetic recording by passing through the material. As elements of the magnetic shielding case related to the method of separating the magnetic pole from the former magnetic pole, "total thickness of cover portion" "thickness of magnetic shielding plate (thickness of synthetic resin foam sheet, thickness of soft magnetic steel plate)" "cover portion "The thickness of each skin", etc., are related, and "the type of high permeability material", "thickness (volume) of high permeability material", etc., as elements of the magnetic shielding case relating to the latter method of arranging the high permeability material Involved. Generally, the number of magnetic flux lines decreases in inverse proportion to the square of the distance from the magnetic pole, and the thicker the plate made of high permeability material, the higher the permeability of high permeability material As a result, the number of flux lines passing through the plate made of the high permeability material tends to increase, and as a result, the number of flux lines leaking from the high permeability material tends to decrease. The magnetic shielding plate of the present invention was studied for the purpose of enhancing the magnetic shielding performance by combining the two methods described above.

  As a result of examining the structure of the magnetic shield plate used in the present invention and the arrangement thereof, the present inventor consists of a soft magnetic steel plate which is a high magnetic permeability material and a synthetic resin foam sheet which is a low magnetic permeability material. The magnetic shield performance is most efficiently improved when it is a laminate, and the surface on the soft magnetic steel plate side of the magnetic shield plate is oriented in the same manner as the cover inner surface facing in the same manner as illustrated in FIG. I found it possible. In other words, this means that the thickness of the magnetic shielding plate required to exert a certain magnetic shielding performance changes depending on the direction of the magnetic shielding plate included in the cover, and as described above, the soft magnetic steel plate of the magnetic shielding plate It means that it becomes possible to design the thickness of the magnetic shield plate thinner if it arranges so that the surface on the side faces the cover inner surface.

(Soft magnetic steel plate)
In order to solve the problems of the present invention, the inventors of the present invention examined various high permeability materials used for the magnetic shield plate, and as a result, it has high magnetic permeability and magnetization, and softness is very small in coercivity when magnetized. It has been found that it is most preferable to use a soft magnetic steel plate, which is a magnetic material, is very inexpensive and has excellent processability, as the high magnetic permeability material of the magnetic shield plate. If a soft magnetic steel plate is used as the high magnetic permeability material of the magnetic shield plate, the required thickness is greater than when using permalloy steel foil, which has a very high magnetic permeability, as the high magnetic permeability material in order to equalize the magnetic shielding performance. Although slightly increased, it has become possible to create a magnetic shielding case with excellent workability and at a much lower cost than permalloy steel foil.

  As a material of the soft magnetic steel sheet used for the magnetic shield of the present invention, it is preferable to use a raw material having a small coercive force when magnetized with high magnetic permeability among iron and iron-based alloys, and pure Iron, iron, electromagnetic soft iron, silicon iron, low carbon steel, electromagnetic stainless steel, ferritic stainless steel, martensitic stainless steel, austenitic / ferritic stainless steel, etc. are listed, but low cost and most excellent workability It is more preferable to use iron, electromagnetic soft iron, low carbon steel, electromagnetic stainless steel, and ferritic stainless steel. Since these raw materials for soft magnetic steel sheets are required to be excellent in workability and soft magnetic, it is preferable that the content of carbon is 0.25 mass% or less. When the content of carbon in the raw material of the soft magnetic steel sheet exceeds the above range, the processability of the soft magnetic steel sheet is gradually deteriorated, and the coercivity tends to be rapidly increased. The soft magnetic steel sheet used in the present invention may be subjected to surface treatment such as plating with a metal such as chromium, zinc, nickel or tin for corrosion protection, if necessary. It is known that the permeability of these soft magnetic steel sheets fluctuates significantly due to processing conditions at the time of preparation and heat treatment after processing, and the magnetic permeability of the soft magnetic steel sheet used in the present invention is not particularly limited. Preferably, the maximum value of the relative permeability is at least 500 or more. If the maximum value of the relative magnetic permeability of the soft magnetic steel sheet is in the above range, the demagnetization performance of the soft magnetic steel sheet is sufficiently good. The coercivity of the soft magnetic steel sheet used in the present invention is preferably 10 Oe or less, more preferably 5 Oe or less. If the coercivity of the soft magnetic steel sheet is in the above range, even if the soft magnetic steel sheet is magnetized, the magnetic information stored in the magnetic stripe or the like is adversely affected or disappears by the magnetic field generated by the soft magnetic steel sheet. There is no need to

  The thickness of the soft magnetic steel plate used as the high magnetic permeability material of the magnetic shield of the present invention is preferably 0.25 mm or more and 0.55 mm or less, and more preferably 0.35 mm or more and 0.55 mm or less. Most preferably, it is 0.45 mm or more and 0.55 mm or less. If the thickness of the soft magnetic steel sheet is within the above range, it is possible to impart excellent magnetism and excellent machinability, but if below the lower limit of the above range, it is possible to provide sufficient magnetic barrier performance to the magnetic case. If the upper limit of the above range is exceeded, the magnetic shielding performance will be further enhanced, but the processability of the soft magnetic steel sheet will tend to be reduced.

(Synthetic resin foam sheet)
As a member used for the magnetic shield plate of the magnetic shielding case of the present invention, the inventor examined a so-called spacer material for reducing the influence of the external magnetic field by spacing the external magnetic field and the magnetic recording portion of the magnetic recording medium. The magnetic permeability plate is a low permeability material with good feel, low hygroscopicity, light weight, excellent shape retention and processability when arranged with the spacer material side of the magnetic shield plate facing the outer surface of the cover. It has been found that it is preferable to use a synthetic resin foam sheet.

  The synthetic resin foam sheet to be used for the magnetic field shield plate may be appropriately selected from sheets using urethane foam, polystyrene foam, polyethylene foam, EVA foam, polyvinyl chloride foam, EPDM foam, synthetic rubber foam, etc. as raw materials. Although it is preferable, it is most preferable to use a polyethylene foam sheet which is particularly low in hygroscopicity and excellent in shape retention.

  The thickness of the synthetic resin foam sheet used for the magnetic shielding plate is the magnetic shielding performance required for the magnetic shielding case, the permeability of the soft magnetic steel plate used for the magnetic shielding plate, the thickness of the soft magnetic steel plate, and the cover of the cover Although it is not possible to uniquely limit only the thickness range because it is affected by the thickness etc., the external recording medium of the magnetic recording medium is an external magnetic field by a magnet having a surface magnetic flux density of 140 mT, In order to prevent the disappearance of the magnetic information recorded in the magnetic recording area, the thickness of the synthetic resin foam sheet is 0.55 mm and the thickness of each skin of the cover is 0.30 mm. It has been found by the study of the inventor that at least 2.00 mm or more is necessary. Conversely, the upper limit of the thickness of the synthetic resin foam sheet is not limited in the same manner, but the greater the thickness, the better the demagnetization performance of the case, but the greater the thickness, the worse the handling of the case. Therefore, the thickness of the synthetic resin foam sheet is preferably 7.00 mm or less, more preferably 5.00 mm or less.

(On the thickness of each component of the cover)
As described above, with respect to "total thickness of cover", "thickness of cover (inner and outer) skins", "thickness of soft magnetic steel sheet" and "thickness of synthetic resin foam sheet", the thickness of each component is other In order to influence the thickness of a structure, in order to determine the thickness of one structure, it is necessary to consider the influence of the thickness of another structure. As a result of examining the performance of the magnetic shielding case and the thickness of each component of the cover, the present inventor stored in the magnetic shielding case by an external magnetic field by a magnet having a surface magnetic flux density of 140 mT which is one of the problems of the present invention. In order to form a magnetic shielding case so that the magnetic information of the magnetic recording medium does not disappear, the surface on the soft magnetic steel plate side of the magnetic shielding plate included in the cover portion is disposed so as to face the inner surface of the cover portion. Assuming that the thickness of the soft magnetic steel sheet is A mm, the thickness of the synthetic resin foam sheet is B mm, the thickness of the cover outer skin is C mm, and the thickness of the cover inner skin is D mm, the following relational expression (1) We found that it is necessary to satisfy all of (5) at the same time.

  The above equation (1) is an equation that limits the range of the thickness of the soft magnetic steel plate, and if the thickness of the soft magnetic steel plate is in the range of 0.25 mm or more and 0.55 mm or less, Further, since the thickness of the steel plate is thin, it is possible to form the magnetic shield case at a low cost. The above equation (2) is an equation for limiting the sum of the thickness of the outer skin of the outer skin portion and the thickness of the synthetic resin foam sheet, in other words, the distance from the outer skin surface of the cover of the magnetic shielding case to the soft magnetic steel plate The distance is at least 2.30 mm or more regardless of the thickness of the cover outer skin and the synthetic resin foam sheet, and when it does not satisfy 2.30 mm, the magnetic shielding case obtains sufficient magnetic shielding performance. It means that you can not do it. The above equations (3) and (4) are equations which limit the lower limit of the thickness of the cover outer skin and the thickness of the cover inner cover, and the thickness of each skin needs to be at least 0.30 mm or more. It shows. The above equation (5) is a equation for further limiting the equations (1) to (3), and more specifically, “the thickness of the soft magnetic steel plate” and “from the outer cover surface of the cover to the soft magnetic steel plate Of the cover (the thickness of the cover outer skin and the thickness of the synthetic resin foam sheet) is further limited. For example, when “the thickness of the soft magnetic steel plate” is 0.25 mm, “the cover "The distance from the outer skin surface to the soft magnetic steel plate" means that 5.30 mm or more is necessary, that is, the sum of the thickness of the cover outer skin and the thickness of the synthetic resin foam sheet is less than 5.30 mm This means that the magnetic shielding case can not obtain an appropriate magnetic shielding performance, and the inventor found such a relationship as a result of intensive investigation of the magnetic shielding performance of the magnetic shielding case and the thickness of each component.

<Bent portion>
The magnetic shielding case of the present invention has a bending portion at a position where the front cover portion and the cover portion are connected to facilitate bending when the magnetic shielding case is folded in two. As shown in FIGS. 3 and 4, the cover may be formed integrally with the cover, or the fold may be formed by connecting the covers separately. Although the raw material of a bending part is not specifically limited, What is necessary is just the thermoplastic synthetic resin sheet | seat which is fundamentally the same as the raw material of a cover part surface skin. The thickness of the bent portion is not particularly limited, but usually needs to be thinner than the cover portion in order to facilitate bending. For example, in the case of integrally forming the cover portion and the bent portion as shown in FIG. As illustrated in the hatched portion of -13b, it is general that the bent portion is configured by welding and joining the cover outer skin and the cover inner skin by welding etc. Depending on the situation, a reinforcing material or the like may be additionally laminated between the skins. In addition, as shown in FIG. 1, slitting (9 in FIG. 1) is performed on each surface on the inside and outside of the bent portion so as to facilitate bending of the bent portion as shown in FIG. It is preferable to perform processing to provide an uneven groove or a ridge.

<Storage section>
The storage unit of the magnetic shielding case of the present invention is provided on the inner skin surface of the cover, and usually has a pocket shape made of a transparent or semi-transparent synthetic resin sheet of a size that just allows a passbook, magnetic card, etc. to fit. Generally, the shape and external dimensions are not particularly limited, and in order to ensure magnetic protection, all the storage portions are smaller in external dimensions than the magnetic shield plate of the cover portion and the entire magnetic storage plate is covered by the magnetic shield plates. Is preferred. The method for forming the storage part is not particularly limited, but in a state in which the synthetic resin sheet to be the storage part is usually laminated on the cover inner skin, the synthetic resin is exemplified as shown by the hatched portion in FIG. In general, the three sides of the sheet are formed by a method such as welding with the cover inner skin by a method such as welding, and the opening of the storage portion is basically shown in FIG. It is opened in the direction of the bent portion so that stored items such as a magnetic recording medium do not easily pop out of the magnetic shield case. Although the raw material of the synthetic resin sheet used for the storage unit is not particularly limited, the thermoplastic synthetic resin sheet similar to the raw material of the cover surface skin is used in consideration of welding and heat sealing. Things are preferred.

  Next, the magnetic shielding case of the present invention will be specifically described by way of examples.

<About each component of magnetic shielding case>
The details of each component of the magnetic shielding case used in the embodiment of the present invention will be described below.
(A sheet made of synthetic resin for the cover inner skin, cover outer skin and folded skin)
・ Polyvinyl chloride resin sheet Thickness: 0.30 mm
(Plastic resin sheet for storage section)
-Polyvinyl chloride translucent resin sheet Thickness: 0.30 mm
(Soft magnetic steel plate)
・ Chrome-plated steel sheet Relative permeability: 4000
Coercivity: 1 Oe
Thickness: 0.25 mm, 0.35 mm, 0.45 mm, 0.55 mm
(Synthetic resin foam sheet)
-Polyethylene foam sheet thickness: 2.00 mm, 3.00 mm, 4.00 mm, 5.00 mm

<Method of forming a magnetic shielding case>
First, a soft magnetic steel plate and a synthetic resin foam sheet are bonded with an adhesive and laminated to form two magnetic shield plates used in the present invention. Next, a storage section is provided by laminating the synthetic resin sheet for the storage section and the cover inner skin and welding the three sides of the synthetic sheet for the storage section to the cover inner skin by high frequency welding processing, The process is repeated once more to provide two storage parts arranged to face each other at a constant distance on the cover inner skin surface so that the openings face each other. Subsequently, the two magnetic shield plates are arranged between the cover inner skin and the cover outer skin so as to face each other at a predetermined interval so as to overlap with the entire storage portion respectively, and soft magnetic steel of the magnetic shield The magnetic shield plate is formed by welding and joining the cover plates to each other by high frequency welding so that the surface on the plate side faces the cover inner surface and the cover side is surrounded immediately outside the magnetic shield. Create two rectangular strip covers that contain. Finally, the front cover of the cover and the cover are welded and joined by high frequency welding, and the inside outer surface is slit to form a bent portion, which is used in the embodiments of the present invention, etc. I created a case. The produced magnetic shielding case has a cross-sectional structure as illustrated in FIG.

  The inventors of the present invention made a plurality of magnetic shield cases using the above-described structure, in which the thicknesses of the soft magnetic steel sheet and the synthetic resin foam sheet are respectively changed, according to the above forming method, as the magnetic shield case used in the examples of the present invention.

<Evaluation of magnetic barrier performance>
Magnetic information is recorded at a recording density of 210 bpi on the magnetic stripe of a JIS-I type magnetic card having a magnetic stripe with a coercive force of 300 Oe by the F2F recording method, and the minimum value of the reproduction signal output of the recorded magnetic information is measured. Do. The cover outer surface facing the magnetic stripe in a state where the magnetic card is stored in the housing of each magnetic shielding case used in the above-described embodiment as shown in FIG. 6 so that the surface of the magnetic stripe faces the cover. A test was conducted by continuously rubbing 10 reciprocations at a rate of 1 reciprocation per second while bringing a magnet (surface X position in FIG. 6) in close contact with a magnet having a surface magnetic flux density of 140 mT. The minimum value of the output was measured, and it was calculated what percentage of the minimum value of the reproduction signal output of the magnetic information of the magnetic stripe before the test was the minimum value of the reproduction signal output of the magnetic information of the magnetic stripe after the test.

  The inventors conducted the evaluation test of the magnetic shielding performance using various magnetic shielding cases prepared for use in the examples, and further analyzed the reading error of the magnetic information recorded on the magnetic stripe of the magnetic card after the evaluation test. As a result, when the minimum value of the reproduction signal output of the magnetic information of the magnetic stripe after the test described above becomes less than 60% of the minimum value of the reproduction signal output of the magnetic information of the magnetic stripe before the test, the data is recorded on the magnetic stripe of the magnetic card Since it was confirmed that the read error of the magnetic information that occurred was generated, the minimum value of the reproduction signal output of the magnetic information of the magnetic stripe after the test is that of the magnetic stripe before the test as the magnetic shield case of the present invention. It is preferable that the magnetic shield case is at least 65% or more of the minimum value of the reproduction signal output of magnetic information, and it is 80% or more. That it was and that the evaluation of the most preferred. For writing of magnetic information on the magnetic stripe of the magnetic card, measurement of reproduction signal output of magnetic information, and analysis of read error of magnetic information, Standard Magnetic Card Analyzer "SV-3000" manufactured by Kenplus Co., Ltd. Using.

  The above-mentioned evaluation test of the magnetic shielding performance is conducted using various magnetic shielding cases prepared by changing the thickness of the soft magnetic steel sheet and the synthetic resin foam sheet for use in the embodiment of the present invention, and the magnetic information of the magnetic stripe after the test Table 1 below shows the results of calculation of what% of the minimum value of the reproduction signal output of the magnetic information of the magnetic stripe before the test is the minimum value of the reproduction signal output.

  Next, as a reference example, it is the same as the magnetic shielding case of Table 1 except that the surfaces of the magnetic shielding case and the magnetic shielding plate on the soft magnetic steel plate side of the magnetic shielding plate are oriented toward the cover outer surface. The same evaluation test of the magnetic shielding performance as in Table 1 is performed using the magnetic shielding case of the configuration, and the minimum value of the reproduction signal output of the magnetic information of the magnetic stripe after the test is the minimum value of the reproduction signal output of the magnetic information of the magnetic stripe before the test. Table 2 below shows the results of calculation of what percentage of

  From the results in Table 1, it can be seen that the cover of two rectangular pieces in which the magnetic shield is enclosed by the synthetic resin skin, at least the fold from one side of each cover to the other, and the storage provided on the inner skin of the cover. A magnetic shielding case configured, wherein the magnetic shielding plate is a laminate of a soft magnetic steel plate and a synthetic resin foam sheet, and the surface of the magnetic shielding plate on the soft magnetic steel plate side is oriented toward the cover inner surface The thickness of the soft magnetic steel sheet is in the range of 0.25 mm to 0.55 mm, and the sum of the thickness of the synthetic resin foam sheet and the thickness of the cover outer skin is 2.30 mm or more, and the cover outer skin and cover A magnetic shielding case is used in which the thickness of the inner skin is both 0.30 mm or more and the sum of the thickness of the synthetic resin foam sheet and the thickness of the cover outer skin is at least 7.80 mm if When a magnetic card having a magnetic stripe with a coercive force of 300 Oe is stored in the housing of the magnetic shielding case, the magnetic information recorded on the magnetic stripe of the magnetic card stored by the external magnetic field by the magnet having a surface magnetic flux density of 140 mT disappears Without reading, it was possible to read magnetic information. Moreover, when Table 1 and Table 2 are compared, the demagnetization performance of the demagnetization plate is higher when installed so that the soft magnetic steel plate side of the demagnetization plate faces the inner skin surface side of the cover, in other words, the demagnetization plate It turned out that it is possible to make thickness thinner.

1; Magnetic shielding case 2; Cover 1
2a; Cover 1 inner surface skin (synthetic resin surface skin)
2b; cover 1 outer surface skin (synthetic resin surface skin))
3; cover 2
3a; cover 2 inner skin (synthetic resin skin)
3b; cover 2 outer surface skin (synthetic resin surface skin))
4; bent portion 5a; storage portion 1
5b; storage section 2
6; Magnetic card (magnetic recording medium)
7; Magnetic stripe (magnetic recording section)
8; bending line 9; slit processing 10a; magnetic shield 1
10b; Magnetic shield 2
11a; soft magnetic steel plate 1
11b; soft magnetic steel plate 2
12a; synthetic resin foam sheet 1
12b; synthetic resin foam sheet 2
13; Welded parts (13a, 13b, 13c)
X: The part that rubs the magnet during the antimagnetic test

Claims (3)

Magnetic recording comprising at least a cover of two rectangular pieces in which a magnetic shield is enclosed by a synthetic resin skin, a bent part connecting one side of each cover, and a storage part provided on the inner skin surface of the cover Magnetic shielding media such as passbooks and magnetic cards with magnetic parts stored in the storage part and held by the cover part, and the magnetic shielding plate is a laminate of soft magnetic steel sheet and synthetic resin foam sheet And the surface of the magnetic shield on the soft magnetic steel plate side is directed to the inner skin surface of the cover, and the thickness of the soft magnetic steel plate is A mm, the thickness of the synthetic resin foam sheet is B mm, and the cover outer skin Magnetic shielding case which satisfies the following relational expressions (1) to (5) when the thickness of C is C mm and the thickness of the cover inner skin is D mm.
  After magnetic information is recorded at a recording density of 210 bpi by the F2F recording method on the magnetic stripe of the JIS-I type magnetic card having a magnetic stripe with a coercive force of 300 Oe, the surface of the magnetic stripe is stored in the magnetic shield case In a state of being stored in such a way that the cover is facing, a test of rubbing 10 consecutive cycles at a rate of 1 reciprocation per second while keeping a magnet with a surface magnetic flux density of 140 mT in close contact with the outer skin surface of the cover facing the magnetic stripe The magnetic shielding case according to claim 1, wherein the minimum value of the reproduction signal output of the magnetic information of the magnetic stripe after the test is 80% or more of the minimum value of the reproduction signal output of the magnetic information before the test.   The magnetic shielding case according to claim 1 or 2, wherein the coercive force of the soft magnetic steel sheet is 10 Oe or less.