JP2009101659A - Cushioning material for press-molding, its manufacturing method, and press-molding method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cushioning material for press-molding being excellent in moldability in order to evenly transmit a pressing pressure to the whole of a body to be molded, and to provide a press-molding method using the cushioning material. <P>SOLUTION: This cushioning material for hot press-molding is equipped with one layer or two layers or more of a felt layer 14, and one layer or two layers or more of polymer layers 12a and 12b containing a super-polymer polyolefine. For the cushioning material, the felt layers and the polymer layers are alternately laminate-bonded, and is used for hot press-molding the body to be molded including electronic equipment components keeping the surface uneven. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cushion material used when a molded body such as a printed circuit board is press-molded. More specifically, the present invention relates to a press-molding cushion material for uniformly transmitting a press pressure to the entire workpiece and a press-molding method using the cushion material.

  In the manufacture of electronic device parts such as a printed circuit board, it is necessary to cover this with a protective sheet in order to protect the wiring pattern formed on the surface thereof. At this time, the protective sheet is covered by press molding or thermocompression bonding, but a cushioning material is provided between the hot platen and the molded body (for example, a printed circuit board) in order to apply heat and pressure uniformly.

  For example, as a cushioning material for such a heat press, a non-woven fabric integrated with a needle punch is used to improve cushioning and heat transfer properties in Patent Document 1, and according to this cushioning material, Even if the printed circuit board had some irregularities, it was possible to apply pressure by making it uniform to some extent. However, when this cushion material is used for pressure-bonding the protective sheet at a position close to the molded body, there has been a problem that the felt base cloth mark and needle mark are transferred to the protective film. Furthermore, the uneven shape that appears due to the wiring pattern on the circuit board has become extremely fine with the development of microfabrication technology, and it is difficult to make the wiring protective film adhere to this fine uneven shape in the film crimping process. For this reason, there are problems such that voids cannot be completely removed and the pressure bonding position of the film is shifted.

  Also, in the manufacturing process of flexible printed circuit boards, there is a cushioning material that copes with the generation of voids caused by the unevenness of the wiring part when a cover lay film based on a polyimide film is pressure-bonded to the flexible circuit board. 2. This document describes a cushion material made of heat-resistant rubber, in which a glass cloth impregnated with a heat-resistant resin is used as a core material, and an aluminum plate is bonded to the surface layer. However, even if this cushioning material is used, it only provides a certain degree of elasticity in the direction in which the press pressure acts, so it cannot cope with the fine uneven shape of the substrate, and the coverlay film is applied to the substrate. The effect of adhering was not sufficient.

Patent Document 3 describes an attempt to solve these problems by forming a film provided between a molded body used for press molding and a hot plate with a layer containing an ultrahigh molecular weight polyolefin. ing. According to this document, when a film for press molding composed of a layer containing an ultra-high molecular weight polyolefin is provided between a press plate and a coverlay film of a molded body and a hot pressing process is performed, the molding film is pressed. Since it is softened by heat and adheres along the uneven shape of the cover lay film, it is possible to transmit the press pressure evenly to the molded body. By doing so, even when the pressing pressure is released after the pressing step, it is possible to obtain a state in which the substrate and the cover lay film are in close contact with each other, and it is possible to prevent the occurrence of gaps and displacement. However, once the hot pressing process is performed, the film for press molding has a low shape restoring property, so it cannot be used repeatedly, and it is a thin film of 1000 μm or less and it is relatively difficult to handle alone. Also, it was necessary to immediately replace the film with a new one, and there were still problems in terms of cost and work efficiency.
JP 2003-145567 A JP-A-8-148814 JP 2007-62175 A

  In view of the above-mentioned problems in the prior art, the problem to be solved by the present invention is that the cushion for hot press molding is superior to the conventional one in terms of cost and work efficiency without impairing the properties as a cushioning material. The object is to provide a material and a hot press molding method using the same.

  As a result of intensive studies to solve the conventional problems as described above, the present inventors have integrated a felt layer and a layer containing an ultra-high-molecular polyolefin to form a printed circuit board. The present inventors have invented an excellent novel cushioning material that can be deformed along the surface shape of the material and can transmit pressure evenly and can be used repeatedly.

  That is, the present invention is a cushion material for hot press molding, comprising the one or more felt layers, and the one or two or more polymer layers containing ultra-high molecular weight polyolefin. Regarding materials.

The present invention also relates to the cushion material in which a felt layer and a polymer layer are alternately laminated and bonded.
Furthermore, this invention relates to the said cushioning material whose at least one of an upper layer or a lower layer is a polymer layer.

Moreover, this invention relates to the said cushioning material whose thickness of a polymer layer is 50-500 micrometers.
Furthermore, this invention relates to the said cushion material used in order to carry out the hot press molding of the to-be-molded body containing the electronic device component which has an uneven | corrugated shape on the surface.

Moreover, this invention relates to the said cushioning material whose thickness of a polymer layer is 500-1000 micrometers.
Furthermore, this invention relates to the said cushioning material whose at least one of an upper layer or a lower layer is a felt layer.
Furthermore, this invention relates to the said cushion material used in order to integrate a prepreg and a copper thin film body by press molding, and to shape | mold a laminated body.

  The present invention is also a method for producing a cushioning material for hot press molding, comprising the steps of preparing one or more felt layers, and one or two or more polymer layers containing ultra-high molecular weight polyolefin. The method includes a step of preparing and a step of bonding and integrating the felt layer and the polymer layer.

  Furthermore, the present invention is a hot press molding method, wherein a cushion material comprising one or more felt layers and one or two or more polymer layers containing ultra-high molecular weight polyolefin is interposed between hot press plates. It is related with the said method characterized by arranging and performing a hot press process.

  According to the cushioning material of the present invention, the press pressure and heat are formed without causing voids (gap) even when there is a fine uneven shape on the surface of the object to be molded, with high followability. Provided is a new heat press molding cushioning material that can be uniformly transmitted to the entire body to perform desired press molding and that can withstand repeated use as a cushioning material, and is excellent in terms of cost and work efficiency. be able to.

  In addition, according to the present invention, even if minute deflection or distortion occurs on the surface of each element used in the pressing process, such as a hot plate, a SUS plate, or a mirror plate of a pressing device, the pressing pressure is made uniform to form a molded body. Can communicate.

  The term “followability” in the present specification means the degree to which the cushion material can be deformed corresponding to the surface shape of the molded body, and when the press pressure is applied, the higher the followability, the higher the followability. Since the pressure can be applied more evenly by being in close contact with the molded body, it can be said that it is very useful in applications requiring precision such as molding and manufacturing of semiconductor parts.

  An example of the basic structure of the cushioning material according to the present invention is shown in FIG. That is, the cushion material 10 includes a felt layer 14 and polymer layers 12a and 12b including an ultrahigh-molecular polyolefin film bonded to the upper and lower surfaces thereof.

  As the felt layer 14, for example, a layer made of a meta-aromatic polyamide or a para-aromatic polyamide can be used. Further, it is also possible to use two felts composed of a meta-aromatic polyamide and a para-aromatic polyamide, which are overlapped and integrated by needle punching. The base fabric 16 of the felt layer 14 is composed of, for example, one or two or more layers of one or more types of spun yarn selected from meta-aromatic polyamide fibers, para-aromatic polyamide fibers, or PBO fibers. Can be used.

  Although the material of the felt layer 14 is not limited to what was illustrated here, What has high thermal conductivity is preferable. In addition, when an electronic device component such as a circuit board is used as a molded body, it is preferable to select a material and a configuration thereof so that static electricity is not generated.

  Also, the thickness of the felt layer is not particularly limited, but if the thickness is increased too much, a desired number of molded articles cannot be processed at once, or misalignment occurs. It is appropriate to do. More specifically, it is preferably about 1 to 2 mm for the inner cushion described later and about 2 to 6 mm for the outer cushion.

Basis weight of the felt layer is not particularly limited, 100 to 1000 g / ^{m 2} for the inner cushion, 1000~2000g / ^{m 2} as Outer cushions, also density those 0.3 to 0.5 g / cm ³ It is preferable to use it.

The “inner cushion” in the present specification means a cushioning material used by being arranged on the molded body side, for example, a cushioning material used in contact with the molded body. In addition, an additional component that does not interfere with the advantageous effects of the cushioning material is used as appropriate.
On the other hand, the “outer cushion” in the present specification is a cushion material used by being arranged on the hot platen side.

  The polymer layers 12a and 12b of the cushioning material 10 according to the present invention are preferably made of ultrahigh molecular weight polyolefin having an average molecular weight of about 1 million to 10 million, more preferably about 2 million to 6 million. As the polymer layers 12a and 12b of the present invention, homopolymers or copolymers of α-olefins such as ethylene, propylene, 1-butene, 1-hexene and 4-methyl-1-pentene can be suitably used. . A specific example is an ultrapolymer (viscosity average molecular weight of 2 million) available from Yodogawa Hutech Co., Ltd. Moreover, you may form the polymer layer 12a or 12b combining these and another polymer.

  The thickness of the polymer layer 12 is preferably 50 to 500 μm when the cushion material 10 is used in contact with the molded body (or a release film described later is sandwiched therebetween).

  Such an ultra-high molecular weight polyolefin is softened and expands when heated to exceed the melting point, but the shape retaining property is not so much lost. Therefore, when this is brought into contact with a molded object having a minute uneven surface and hot pressing is performed, the layer made of ultra-high molecular weight polyolefin is deformed along the surface of the molded object, and the cushion material and the molded object It is possible to create a state where there is no gap between them. By applying the press pressure in such a state, it becomes possible to apply pressure evenly to the entire molding target.

  In the embodiment shown in FIG. 1, the polymer layers 12 a and 12 b containing ultrahigh molecular weight polyolefin are bonded so as to sandwich the felt layer 14. With such a laminated structure, the felt layer 14 not only transmits pressure uniformly as a cushion, but also acts as a support for the polymer layers 12a and 12b as described later. In the present invention, when bonding between the polymer layer and the felt layer, an adhesive is used, the polymer layer is heated and melted to be integrated with the felt layer, or a hot-melt fiber is disposed in the felt layer. A method such as heating and melting can be employed.

  The cushion material of the present invention is not limited to the one made of the felt layer 14 shown in FIG. 1 and the pair of polymer layers 12a and 12b, but includes two or more felt layers 14 or polymer layers 12, For example, as shown in FIG. 2, two felt layers 14a and 14b, a polymer layer 12a provided on the upper surface of the felt layer 14a, a polymer layer 12b provided on the lower surface of the felt layer 14b, a felt layer 14a, It is good also as cushioning material 10 'which consists of the polymer layer 12c provided between 14b.

Next, the process of hot press molding the molded body 20 using the cushion material 10 according to the present invention as an inner cushion will be described with reference to FIG.
The press molding method of the present invention is performed in order to protect the wiring 28 applied on the surface of the substrate 18 by pressure-bonding the coverlay film 24 to a molded body 20 such as a printed wiring board.
In addition, the wavy line in FIG. 3 means that illustration of the part was abbreviate | omitted.

  As the coverlay film 24, for example, a film based on a polyimide film can be used, such as a polypyromellitic acid imide film, a polybiphenylimide film, a polyketoneimide film, a polyamideimide film, a polyether. Examples thereof include an imide-based film. Further, the cover lay film 24 is configured such that, for example, an adhesive of a thermosetting resin is attached to the cover lay film 24 so that the cover lay film 24 can be bonded to the molded body 20 by heating and pressing.

As shown in FIG. 3, the to-be-molded body 20 is installed between the hot plates 22a and 22b of a press apparatus, and the coverlay film 24 is mounted on it. Then, a press pressure is applied to the object to be molded through the cushioning material 10 or 10 ′ (see FIGS. 1 and 2) including the felt layer 14 and the polymer layer 12 containing ultrahigh molecular weight polyolefin, and the stainless steel plate 30.
In addition, you may provide the release film 26 between the cushioning material 10 and a to-be-molded body. This is provided to easily separate the cushion material 10 from the molded body 20 after the pressing process.

  When the press device is operated to bring the hot plates 22a and 22b closer to press the molded body 20, heat is transferred from the hot plates 22a and 22b to the stainless steel plate 30, the cushion material 10, and the coverlay film 24 in this order. At this time, the ultra-high molecular weight polyolefin contained in the polymer layer 12 of the cushioning material 10 is softened by heat and expands while being deformed along the surface shape of the molded body 20 by pressure from a press device. The cover lay film 24 is brought into close contact with the surface shape of the molded body 20 in response to the deformation of the cushion material 10, and is then pressed onto the molded body without any gap by an adhesive made of a thermosetting resin.

  When the pressure bonding of the coverlay film 24 to the molded body 20 is completed, the press device is operated to separate the heating plates 22a and 22b from each other, thereby releasing the press pressure. And the to-be-molded body 20 is removed, and the to-be-molded body which should be processed next is installed in a press apparatus. At this time, the cushioning material 10 used in the pressing process does not need to be replaced and can be used continuously. This is because the polymer layers 12a and 12b of the cushioning material 10 of the present invention are bonded to the felt layer 14 having high shape retaining property on the upper surface or the lower surface thereof before and after the pressing process, so that the vicinity of the adhesion site is the felt layer 14. The deformation amount is suppressed by being supported by, and the restoring force inherent in the ultra-high molecular weight polyolefin material is applied by heating, so that the polymer layers 12a and 12b are substantially recovered to the shape before the press treatment. is there.

  As described above, by forming the cushion material 10 as a combination of the felt layer 14 and the polymer layers 12a and 12b, the cushioning property and the temperature rise property (thermal conductivity) of the felt and the expansibility due to the heating of the ultra-polymer polyolefin are increased. In addition, it is possible to provide an excellent cushion material that has a restoring property and that ensures dimensional stability as a cushion material by a combination thereof.

(Example 1) Implementation for inner cushion (Example 1-1)
The cushion material according to Example 1-1 is a cushion material for the inner cushion of the aspect illustrated in FIG. 1, the felt basis weight of the felt layer is 400 g / m ^2, and the thickness of the polymer layer including the ultra-high molecular polyolefin is set. Each of the upper surface and the lower surface is 50 μm (100 μm as the whole polymer layer).

(Example 1-2)
The cushion material according to Example 1-2 is a cushion material of the inner cushion material of the aspect illustrated in FIG. 1, the felt basis weight of the felt layer is 400 g / m ^2, and the thickness of the polymer layer including the ultra-high molecular polyolefin is set. Each of the upper and lower surfaces is 250 μm (the entire polymer layer is 500 μm).

(Example 1-3)
The cushion material according to Example 1-3 is a cushion material of the inner cushion material of the aspect shown in FIG. 1, the felt basis weight of the felt layer is 400 g / m ^2, and the thickness of the polymer layer containing the ultra-high molecular polyolefin is set. Each of the upper surface and the lower surface is 500 μm (the entire polymer layer is 1000 μm).

(Comparative Example 1A)
The inner cushion material according to Comparative Example 1A is composed of only a felt layer, and the basis weight of the felt is 400 g / m ² which is the same as each example.

(Comparative Example 1B)
The inner cushion material according to Comparative Example 1B is composed of only a polymer layer containing ultra-high molecular polyolefin. The thickness was 250 μm, which is the same thickness as the polymer layer of Example 1-2.

Table 1 shows the results of the hot press molding process for the electronic circuit board using the cushion materials of Examples 1-1, 1-2, and 1-3 and Comparative Examples 1A and 1B as inner cushions. Shown in

  As can be seen from Table 1, the cushioning material according to each example of the present invention has good adhesiveness of the coverlay film and does not cause gaps or displacement between the coverlay film and the substrate, and is excellent in repeated handling. Results were obtained.

  Next, an embodiment in which the cushion material of the present invention is used as an outer cushion will be described with reference to FIG. In addition, the wavy line in FIG. 4 means that illustration was abbreviate | omitted about the part.

  One of the embodiments using a cushion material as the outer cushion is shown in FIG. In this aspect, the cushion material 50 of the present invention is used when the copper foils 42a and 42b and the prepreg 40 are bonded to form a laminate. The prepreg 40 in this embodiment is configured by stacking a plurality of semi-cured plate materials in which a glass cloth is impregnated with an epoxy resin.

  Then, heat and pressure are simultaneously applied by the heating plates 22a and 22b with the specular plates 44a and 44b sandwiched therebetween, and the prepreg 40 and the copper foils 42a and 42b are laminated and formed. In this case, when the conventional cushioning material is used, if the temperature rising rate (heat transfer amount) of the cushioning material does not meet the design conditions, the portion between the heating platen 22a or 22b and the heating platen 22a, 22b There may be a difference in physical properties of the molded body between the positioned portion and the quality of the final product may be deteriorated. On the other hand, when the cushion material 50 of the present invention is used as an outer cushion, the cushion material 50 acts so as to compensate for distortion caused in the pressure distribution by the press device due to various factors. The pressure can be made uniform and transmitted to the object to be molded.

  FIG. 5 shows a basic configuration of the cushion material 50 for an outer cushion according to the present invention. That is, the cushion material 50 includes a felt layer 54 and a polymer layer 52 (52a, 52b) containing an ultra-high molecular weight polyolefin that is integrally bonded to the upper and lower surfaces of the felt material layer 54.

(Example 2) Implementation for outer cushion (Example 2-1)
The cushion material according to Example 2-1 is a cushion material for the outer cushion of the aspect illustrated in FIG. 5, and the felt basis weight of the felt layer is 2000 g / m ^2, and the thickness of the polymer layer containing the ultra-high molecular polyolefin is set. Each of the upper surface and the lower surface is 500 μm (the entire polymer layer is 1000 μm).

(Example 2-2)
The cushion material according to Example 2-2 has the same configuration as that shown in FIG. 5, the felt weight of the felt layer is 1500 g / m ^2, and the thickness of the polymer layer is 1000 μm on each of the upper surface and the lower surface ( The whole polymer layer is 2000 μm).

(Comparative Example 2A)
Comparative Example 2A is a cushion material composed only of a felt layer, and the felt basis weight is 2400 g / m ² .

(Comparative Example 2B)
Comparative Example 2B is a cushion material that is also composed of only a felt layer, and has a felt weight of 1500 g / m ² .

Table 2 below shows the results of performing the hot press molding process of the electronic circuit board using the cushion materials of Examples 2-1 and 2-2 and Comparative Examples 2A and 2B described above as outer cushions.

In addition, the hot press process here was implemented by applying the load of 40 kg / cm for 60 minutes at the temperature of 200 degreeC, and repeating this 10 times. The cushion displacement amounts in Table 2 are expressed as positive values when the thickness is reduced by compression. That is, the fact that the amount of displacement of the cushion material at the time of heating press in Example 2 is a negative value means that the polymer layer expands as a result of the application of heat and the overall thickness increases. Yes.
The reached temperature in the table is the temperature reached after repeating the pressing operation 10 times, and the numerical value in the table is a value 60 minutes after reaching 30 ° C. This is a reference when adjusting the weight of the felt according to the specification, and it is necessary to reduce the weight per unit when increasing the ultimate temperature and to increase the basis weight when lowering the ultimate temperature.

  As can be seen from Table 2, when the cushioning material according to each embodiment of the present invention is used, the polymer layer as a constituent element expands due to heat, and is uniform on the entire surface of the molded body corresponding to the distortion of the press device. The press pressure can be applied, and the adhesion (presence / absence of voids, substrate thickness unevenness) of the molded body was improved.

(Other embodiments according to the present invention)
In the above embodiment, the polymer layer containing the ultra-high molecular polyolefin has been described based on the outer side (upper surface and / or lower surface). However, such a polymer layer is provided between the felt layers, and the felt layer is used instead. Also, those that are arranged on the outside can be suitably used particularly for the outer cushion.

  FIG. 6 shows a configuration example of the cushioning material of the present invention in which a felt layer is disposed on the outside. That is, the cushion material 60 according to this aspect includes the felt layers 64a and 64b and the polymer layer 62 containing the ultra-high molecular polyolefin sandwiched therebetween.

  The embodiment shown in FIG. 7 includes felt layers 74a, 74b, and 74c, and polymer layers 72a and 72b containing ultra-high molecular polyolefin sandwiched therebetween.

  As described above, the cushioning material according to the present invention can be used as a cushioning material for hot press molding that has good cushioning properties and moldability and is excellent in cost and efficiency that can be used repeatedly. Further, by using such a cushioning material, the hot press molding method of the present invention can enjoy the above-mentioned advantages, and is extremely useful when press molding electronic device parts such as a printed wiring board.

It is a figure which shows the one aspect | mode of the cushioning material of this invention. It is a figure which shows the one aspect | mode of the cushioning material of this invention. It is the schematic diagram showing the structure of the press apparatus at the time of performing hot press molding using the cushion material of this invention. It is the schematic diagram showing the structure of the press apparatus at the time of performing hot press molding using the cushion material of this invention. It is a figure which shows another aspect of the cushioning material of this invention. It is a figure which shows another aspect of the cushion material of this invention. It is a figure which shows another aspect of the cushion material of this invention.

Explanation of symbols

10, 10 'Cushioning material 12 (12a, 12b, 12c) Polymer layer 14 (14a, 14b) Felt layer 16 Base fabric 18 Substrate 20 Molded body 22a, 22b Heating plate 24 Coverlay film 28 Wiring 30 Stainless steel plate 40 Prepreg 42 (42a, 42b) Copper foil 44 (44a, 44b) Mirror plate 50 Cushion material 52 (52a, 52b) Polymer layer 54 Felt layer 60 Cushion material 62 Polymer layer 64 (64a, 64b) Felt layer 70 Cushion material 72 (72a, 72b) Polymer layer 74 (74a, 74b, 74c) Felt layer

Claims (10)

A cushioning material for hot press molding,
One or more felt layers;
One layer or two or more polymer layers containing ultra-high molecular polyolefin;
The cushion material comprising:   The cushion material according to claim 1, wherein a felt layer and a polymer layer are alternately laminated and bonded.   The cushion material according to claim 1 or 2, wherein at least one of the upper layer and the lower layer is a polymer layer.   The cushion material in any one of Claims 1-3 whose thickness of a polymer layer is 50-500 micrometers.   The cushion material in any one of Claims 1-4 used in order to carry out the hot press molding of the to-be-molded body containing the electronic device component which has an uneven | corrugated shape on the surface.   The cushion material in any one of Claims 1-3 whose thickness of a polymer layer is 500-1000 micrometers.   The cushion material according to claim 1, 2 or 6, wherein at least one of the upper layer and the lower layer is a felt layer.   The cushion material according to claim 1, 2, 6, or 7, which is used for forming a laminate by integrating a prepreg and a copper thin film body by press molding. A method of manufacturing a cushioning material for hot press molding,
Providing one or more felt layers;
Preparing one or two or more polymer layers containing ultra-high molecular polyolefin;
Adhering and integrating the felt layer and the polymer layer;
Said method. A hot press molding method,
A cushioning material comprising one or two or more felt layers and one or two or more polymer layers containing ultra-high molecular weight polyolefin is disposed between hot press plates to perform a hot pressing process. , Said method.

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