JPH04282299A - Information card and production thereof - Google Patents

Abstract

PURPOSE:To obtain an information card having no possibility of applying an excessive stress to a printed board and mounted elements. CONSTITUTION:As a resin sealing layer 21 in which a printed board 2, mounted elements 3, such as IC elements, and the like are to be embedded, a material having a molding contraction coefficient of 0.1% or less, such as a polyester premix, is used. The position of a gate 14 for forming the resin sealing layer 21 is determined to be slightly higher than a bottom face 12A of a cavity 12. In this manner, the printed board 2 is prevented from rising in the cavity 12.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information card generally referred to as an IC card, which is equipped with an IC element or the like and used as a multipurpose information storage medium in various card systems, and a method for manufacturing the same.

0002

[Prior Art] Information cards such as IC cards include contact type cards that are connected to the terminal through mechanical contacts when the card is inserted into the card reader of the card system terminal, and There are contactless cards that are connected in a non-contact manner via a signal transmitting/receiving section and a power transmitting section by electromagnetic coupling or the like. Although the configurations of the circuits mounted on the printed circuit board are different from each other, it is known that the memory capacity is large, ranging from several tens of kilobytes to several hundred kilobytes, and the memory life is as long as about five years.

[0003] Also, the external dimensions of the information card are 54 mm in width.
, 86 mm long and several mm thick, and a contact card with a connector on the end face in the width direction sends and receives signals to and from the terminal and determines positioning via the connector, while a non-contact card has a connector on the end surface in the width direction. Since signals and power are transmitted by mutual electromagnetic coupling between the machine side and the card side, mutual positional deviation becomes a problem. Therefore, the accuracy of the external dimensions determined by the resin sealing portion and the positioning accuracy of the circuit elements contained therein are important. Taking this requirement into consideration, the conventional sealing structure for contact cards is to house the card body in a metal exterior case, cover it with a metal cover, position it, and then fix it with screws or adhesive. It is known that a metal exterior case containing a main body is filled with a casting resin such as epoxy resin and cured to seal and fix the case. In the case of a contactless card, you can either insert the card into a hard resin case and fix the hard resin cover to the case by gluing or screwing it in place. It is known that the molding resin is filled and cured to seal and position the molded resin.

0004

[Problems to be Solved by the Invention] Information cards are subject to mechanical stress such as friction, compression, bending, vibration, and impact, as well as thermal stress of up to about 50°C, due to being carried by the user for a long period of time. Subject to stains due to moisture such as sweat and water. Also,
Mechanical stress is also applied by repeated insertion into a terminal's card reader. Therefore, in the conventional sealing structure using a case cover, repeated stress causes problems such as loosening of set screws or peeling of adhesive, which can cause damage to the card body, misalignment, or damage to the card body. Alternatively, the card may become soiled and the card's original function may deteriorate. Furthermore, it requires assembly processes such as gluing and screwing, which are difficult to save labor, which hinders the effectiveness of mass production.

Furthermore, with the conventional structure in which the case is filled with epoxy resin, mechanical strength, positioning performance, and environmental resistance are improved; Shrinkage during curing tends to cause deformation of the case and circuit elements, which not only reduces the yield of good products, but also increases the number of processing steps due to the addition of casting resin injection and curing. There are drawbacks. On the other hand, attempts have been made to seal the card body by integrally molding resin, but it is difficult to position a non-contact type card in a mold because the card body does not have a protrusion that can be used to position a connector or the like. Furthermore, when positioning pins or the like are provided on the card body side or the mold side, marks of the positioning pins and their holes remain on the surface of the completed card, creating a new weak point.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks and provide an information card with high product quality and good productivity, as well as a manufacturing method thereof.

[0007]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a printed circuit board and its printed circuit board with a resin composition made of, for example, polyester premixes having a molding shrinkage rate of 0.1% or less. At least I
It is characterized by being integrally molded with a C element embedded therein.

In order to achieve the above-mentioned object, the present invention further provides a method for manufacturing an information card in which a printed circuit board and at least an IC element mounted on the printed circuit board are embedded and integrally formed. The printed circuit board is positioned with a positioning member such as a positioning pin provided in the molding die, the mold is clamped, and then a predetermined height is placed between the side wall surface of the cavity near the positioning member and the bottom surface of the cavity. This is characterized in that a molding resin is injected through a gate that is opened so as to leave a wall surface, and the printed circuit board and at least the IC element are embedded and integrally molded.

As mentioned above, the resin composition for embedding printed circuit boards and IC elements has a molding shrinkage rate of 0.1.
% or less, printed circuit boards and I
There is no distortion of the C element, and quality can be improved.

Furthermore, as described above, since the printed circuit board can be properly held within the mold by the positioning member, the printed circuit board and the like can be accurately embedded in a predetermined position. In addition, by setting the opening position of the gate at a predetermined height (approximately half the maximum thickness of the card body) higher than the bottom of the cavity, the molding resin injected into the cavity flows on the top surface of the board. The action of pressing the printed circuit board against the bottom side of the cavity prevents the card body from lifting up, exposing the surface of the printed circuit board on the side opposite to the circuit elements, and making it easy to apply the resin sealing layer to the circuit element side with high dimensional accuracy. can be formed with. In addition, the printed circuit board with one side exposed has appropriate rigidity, and the circuit element side is reinforced with a resin sealing layer, so the exposed side of the printed circuit board is further covered with a resin sealing layer. There is no need to reinforce it.

[0011]

[Embodiment] The present invention will be explained below based on one embodiment. FIG. 1 is a side sectional view of essential parts for explaining the method for manufacturing a resin sealing layer in an embodiment of the present invention, FIG. 2 is a side sectional view of an information card in the embodiment, and FIG. 3 is a plan view of the information card. FIG. 4 is a characteristic diagram showing the relationship between the amount of the low shrinkage agent added and the molding shrinkage rate. In FIG. 1, 11 is a mold,
Consisting of a lower mold 1A and an upper mold 1B, a plurality of flat box-shaped cavities 12 are provided inside the mold, and each cavity 12
For example, an injection molding machine (not shown) is connected via a gate 14 serving as an injection port opened at a predetermined height position on one side wall surface 12B on the short side and a runner 13 communicating with the plurality of gates 14 and serving as a resin flow path. connected to the nozzle. Furthermore, positioning pins 15 are provided protruding from the bottom surface 12A of the cavity 12 at least at two locations spaced apart along the side wall surface 12B. In addition, a rectangular printed circuit board 2 made of a glass fiber-reinforced epochite resin board, a glass fiber-reinforced polyester resin board, etc. is equipped with various IC elements such as IC memory elements, electromagnetic coupling type signal transmitting/receiving elements, power transmission elements, etc. The card body 1 is constructed by mounting the mounting elements 3 and interconnecting the elements by printed wiring. At least two holes 2B for inserting the positioning pins 15 are formed in advance in the printed circuit board 2 at intervals along its short side (see FIG. 3). By setting the card body 1 on the bottom surface of the cavity 12 so that the pin 15 and the hole 2B fit together, the card body 1 is attached to the cavity 12.
is positioned at a predetermined position within.

On the other hand, when the maximum thickness of the card body 1 is t, the depth T of the flat portion of the cavity 12 is approximately the sum of the thickness t of the card body 1 and the thickness ta of the printed circuit board 2. , so that it doesn't get too big. Up,
After the lower mold is clamped, a gap ta is maintained between the card body 1 and the upper mold 11B. Further, a margin of more than 10 mm is maintained between the printed circuit board and the side wall of the cavity 12, and a groove 12c with a depth of about 0.1 mm is formed along the side wall of the cavity 12. Further, the opening of the gate 14 is provided at a position higher than the bottom surface 12A of the cavity 12 by about half or more of the maximum thickness t of the card body 1, and a low-shrinkage casting resin 19, which will be described later, is transferred from an injection molding machine to a runner. 13, is injected into the cavity 12 through the gate 14. Since the gate 14 is provided at the upper part of the side wall of the cavity 12, the molding resin 19 injected into the cavity 12 at this time passes through the upper surface side of the printed circuit board 2 and fills the void in the cavity 12.
Since there is little wrapping around the bottom side of the printed circuit board 2,
As a result, the printed circuit board 2 receives a pressing force from the molding resin 19 against the bottom surface 12A of the cavity 12. Therefore, the card body 1 is prevented from lifting up during casting, and at the same time, the horizontal movement of the card body 1 is also prevented by the engagement portion between the positioning pin 15 and the hole 2B, so that the card body 1 is not placed in the cavity. The resin sealing layer 21 can be formed while being precisely positioned at a predetermined position within the resin sealing layer 12 . To release the mold after completion of molding, first remove the upper mold 11B, and if the resin in the runner 13 is pushed up by the mold release pin 16 provided on the lower mold 11A side facing the runner 13, the molded product will be released. The mold can be released with minimal distortion. After the mold release, the memory card with the gate 14 portion of the resin layer removed has a resin sealing layer 21 integrated with the printed circuit board 2, leaving one surface of the printed circuit board 2, as shown in FIG. Therefore, if the film sealing layer 22 is formed by applying and bonding a moisture-proof polyester film or metal film with adhesive applied to one side to the entire smooth surface of the printed circuit board 2, including the exposed surface, the card body An information card in which 1 is completely covered with resin or the like is obtained. In addition, with respect to the thickness T1 of the peripheral edge of the card, the two flat surfaces on the inside are each 0.1 m.
Since it is in a recessed state, the film sealing layer 22 is adhered to one recess, and the label 20 is adhered to the other recess, so that an information card with smooth surfaces on both sides is obtained.

As the casting resin 19, for example, polyester premix resin, epoxy resin, etc. are used. Examples of the composition of the polyester premix resin are as follows. Unsaturated polyester resin (styrene monomer 40
% mixture) 100 parts by weight Styrene monomer
15 parts by weight
Polyvinyl acetate and polystyrene block copolymer
25 parts by weight inorganic filler
300 parts by weight
glass fiber

40 parts by weight Colorant

FIG. 4 shows the changes in mold shrinkage when the amount of the low shrinkage agent (polyvinyl acetate-polystyrene copolymer) added to 100 parts by weight of the base resin (unsaturated polyester resin) was varied. As is clear from this figure, by adding 10 parts by weight or more, preferably 15 parts by weight or more of a low shrinkage agent to 100 parts by weight of the base resin, the molding shrinkage rate can be suppressed to 0.1% or less. In addition, the amount of low shrinkage agent added is 30
If the amount exceeds 1 part by weight, the appearance will be uneven, which is not desirable in terms of quality. Therefore, the amount of the low shrinkage agent is preferably regulated within the range of 10 to 30 parts by weight. When using an epoxy resin as the casting resin, the molding shrinkage rate can be controlled to 0.1% or less by increasing the amount of filler such as quartz powder.

[0014]

Effects of the Invention: Thermosetting resins having various molding shrinkage rates were prepared by varying the amount of low-shrinkage agent added in the polyester premix, and these molding resins were used to create molds as shown in Figures 2 and 3.
Create an information card with the structure shown in . The relationship between the molding shrinkage rate and residual stress of the resin sealing layer in this information card was investigated, and the results are shown in the following table.

[Table 1] Mold shrinkage rate Residual stress (σ=ε・E) kgf
/mm20.05 0.4
250.1 0.85
0.3 2.550.
5 4.251.0
8.5ε: Molding shrinkage rate E: Elastic modulus 850 kgf/mm2 Among electronic components mounted on printed circuit boards, capacitors and crystal oscillators, which are relatively stress sensitive, have a residual stress of 1 kgf/mm.
It has been experimentally confirmed that if it exceeds 2, it will be destroyed. As is clear from the above table, when the molding shrinkage rate of the resin sealing layer exceeds 0.1%, the residual stress increases to 2.55 kgf/mm.
2 or more, leading to destruction of electronic components as described above. On the other hand, when the molding shrinkage rate is 0.1% or less, the residual strain is 0.85 kgf/mm 2 or less, and there is no fear that the electronic component will be destroyed. Therefore, the molding shrinkage rate of the resin sealing layer must be regulated to 0.1% or less.

Furthermore, the horizontal position on the bottom surface of the cavity is regulated by the positioning member, and the pressing force of the inflowing resin presses against the bottom surface and prevents it from lifting up, which is difficult to achieve with conventional molding methods. A resin sealing layer with high external dimensional accuracy and positioning accuracy can be easily formed even on non-contact type cards.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a main part for explaining a method of manufacturing a resin sealing layer according to an example of the present invention.

FIG. 2 is a side view of the information card according to this embodiment.

FIG. 3 is a plan view of this information card.

FIG. 4 is a characteristic diagram showing the relationship between the amount of low shrinkage added and molding shrinkage.

[Explanation of symbols]

1　Card body 2 Printed circuit board 3 Mounted elements 11 Molding mold 12 Cavity 14 Gate 15 Positioning pin 21 Resin sealing layer

Claims (7)

[Claims] 1. An information card characterized in that a printed circuit board and at least an IC element mounted on the printed circuit board are embedded and integrally molded using a resin composition having a molding shrinkage rate of 0.1% or less. 2. The information card according to claim 1, wherein the resin composition is a polyester premix. 3. The polyester premix according to claim 2, wherein the polyester premix has a molecular weight of 20
An information card characterized in that it is a composition containing ~25% by weight of a polyvinyl acetate-polystyrene block copolymer, an inorganic filler, and a catalyst. 4. A method for manufacturing an information card in which a printed circuit board and at least an IC element mounted on the printed circuit board are embedded and integrally molded, wherein the printed circuit board on which at least the IC element is mounted is provided in a molding die. After positioning with the member and clamping the mold, casting resin is applied to the side wall surface of the cavity near the positioning member through a gate opened so as to leave a wall surface of a predetermined height between it and the bottom surface of the cavity. A method for manufacturing an information card, characterized in that the printed circuit board and at least an IC element are embedded and integrally molded by injection. 5. The method for manufacturing an information card according to claim 4, wherein the molding shrinkage rate of the casting resin is 0.1% or less. 6. The method for manufacturing an information card according to claim 4, wherein the casting resin is polyester premix. 7. The polyester premix according to claim 6, wherein the polyester premix has a molecular weight of 20% based on the unsaturated polyester resin.
A method for producing an information card, characterized in that the composition is a composition containing ~25% by weight of polyvinyl acetate-polystyrene block copolymer, an inorganic filler, and a catalyst.