KR102468401B1 - Cushioning material for hot press and method for producing the same - Google Patents

Abstract

[PROBLEMS] To provide a new and improved cushioning material for hot pressing and a method for manufacturing the cushioning material for hot pressing, which are excellent in transportability of automatic stacking and peelability from hot plates, and suppressed fluffing during use.
[Solution] A cushioning material for hot pressing according to the present invention has a base material, a batt fiber layer having a softened and smoothed outer surface disposed on a first main surface of the base material, and an airtight sheet layer disposed on a second main surface surface of the base material. . The airtight sheet layer may be composed of a fiber sheet or a resin film.

Description

Cushioning material for hot press and manufacturing method for cushioning material for hot press {Cushioning material for hot press and method for producing the same}

The present invention relates to a cushioning material for heat-pressing and a method for manufacturing the cushioning material for hot-pressing.

In general, in the manufacture of electric components having a laminated structure such as printed wiring and liquid crystal display panels, and building materials having a laminated structure such as laminated materials, decorative sheets, and laminated materials, laminates For the purpose of press molding or hot pressing, hot-press is performed.

For example, a printed wiring board is manufactured by laminating a prepreg made of resin and copper foil, and then pressurizing and heating by a heat board, that is, hot pressing. . In the heat press, the prepreg is cured gradually after the viscosity is once lowered by heating and returned to a liquid state. In such a hot press, pressure and temperature distribution applied to the laminate are required to be uniform.

For this purpose, a cushioning material for hot press is generally used in hot press. The cushioning material for hot pressing is disposed between the hot disc and the laminated body, and the pressure and temperature applied in the hot disc are distributed in the lateral direction, thereby making the pressure distribution and temperature distribution of the hot press uniform. Therefore, cushions for hot pressing are required as basic properties such as appropriate deformation followability, cushioning properties, thermal conductivity, and high durability (for example, heat resistance) in order to uniformize pressure distribution and temperature distribution.

In Patent Document 1, unstretched meta-aromatic polyamide fibers or a web containing the fibers are provided on the end surface or the entire surface of a substrate in which all or main fibers are made of meta-aromatic polyamide. Disclosed is a heat-resistant cushioning material in which a cover layer made of is provided and heat-treated at a temperature equal to or higher than the glass transition point of the meta-aromatic polyamide fibers.

Patent Document 2 discloses a heat-resistant cushioning material in which an airtight layer made of heat-resistant fibers is formed on the surface of a main body made of heat-resistant fibers.

Patent Document 3 includes a first nonwoven fabric constituting an inner layer and a second nonwoven fabric disposed on both sides of the first nonwoven fabric and constituting an outer layer, and the second nonwoven fabric is a constituent material and has a weight per unit area ) is 80 ~ 400 g / m ² Copolymerized para-aramid fibers are used, and the first nonwoven fabric uses a fiber having higher stiffness than the copolymerized para-aramid fibers as its constituent material, Disclosed is a cushioning material for heat press, wherein the heat resistance temperature of the second nonwoven fabric and the second nonwoven fabric is 270° C. or higher, respectively.

[Patent Document 1] Patent Publication No. 6-91780 [Patent Document 2] Patent Publication No. 8-169074 [Patent Document 3] Japanese Patent Publication No. 2014-37654

However, in order to smoothly perform the hot pressing process, cushioning materials for hot pressing are generally required to have good peel off properties with the hot plate. In addition, when using a cushioning material for hot pressing, it is necessary to suppress fluff of the constituting fiber material and subsequent detachment (hair loss). When hair loss occurs, the separated fiber material may be incorporated into the laminate and adversely affect the final product.

On the other hand, for the purpose of automating the hot press process, there is a case where a cushioning material for hot press is automatically loaded. In this automatic stacking, the cushioning material for hot pressing is lifted, conveyed, and replaced by suctioning and holding the cushioning material for hot pressing. Here, the cushioning material for hot pressing tends to be lighter in recent years, and therefore, even in an automatic loading device, there is a tendency to perform suction with a weaker suction force than before. Therefore, cushioning materials for hot pressing are required to have good transportability, enabling automatic loading even with a weak suction force compared to the conventional ones.

Here, the cushion for hot press having a fiber layer and a nonwoven fabric layer as the surface layer as described in Patent Document 1 and Patent Document 3 does not have sufficient conveyance property corresponding to such a recent automatic conveyance trend. On the other hand, when an airtight layer is provided as described in Patent Literature 2, the peelability with the hot disc is not sufficient. In this way, the cushioning materials for hot pressing described in Patent Literatures 1 to 3 described above did not simultaneously satisfy the performance as described above.

Therefore, the present invention has been made in view of the above problems, and the object of the present invention is a new and improved cushioning material for hot press, which has excellent transportability of automatic stacking and peelability with a hot plate, and suppresses fluff during use, and a heat press. It is providing the manufacturing method of the cushioning material for presses.

In order to solve the above problems, according to one aspect of the present invention, a base material, a vat fiber layer disposed on a first main surface of the base and having an outer surface softened and smoothed, and the base material A cushion for heat press having an airtight sheet layer disposed on the side of the second main surface of the cushion is provided.

The batt fiber layer may be softened and smoothed at a temperature equal to or higher than the glass transition temperature of batt fibers, including batt fibers.

In addition, in order to solve the above problems, according to another aspect of the present invention, it has a base material, a vat fiber layer disposed on the first main surface of the base material, and an airtight sheet layer disposed on the second main surface side of the base material, At least a portion of the outer surface of the batt fiber layer is provided with a cushioning material for hot pressing composed of fibers forming a flat shape along the outer surface.

The airtight sheet layer may be composed of a fiber sheet or a resin film.

A surface roughness Ra of the outer surface of the batt fiber layer may be 2.5 to 11 μm.

Air permeability in the form of a Frazier specified in JIS L 1096 may be 0.2 cm ³ /cm ² /sec or less.

The batt fiber layer may include unstretched meta-aromatic polyamide fibers.

The fineness of the batt fibers constituting the batt fiber layer may be 0.8 to 11 dtex.

The cushioning material for hot pressing may also have a vat fiber layer disposed between the substrate and the airtight sheet layer.

The substrate may include aromatic polyamide fibers.

In addition, in order to solve the above problems, according to another aspect of the present invention, batt fibers are disposed on at least one main surface of the substrate and needling is performed, and the batt fiber layer is formed on at least one main surface of the substrate. A step of forming and obtaining a laminate;

A method for producing a cushioning material for hot pressing, comprising a step of pressing at a temperature equal to or higher than the glass transition temperature of the vat fiber in a state where an airtight sheet is disposed on the other main side surface of the base material in the laminate, is provided.

As described above, according to the present invention, it is possible to provide a new and improved cushioning material for hot pressing and a method for manufacturing the cushioning material for hot pressing, which are excellent in transportability and peelability from a hot plate in automatic stacking and suppressed fluffing during use. can

1 is a schematic view showing an example of a state of use of a cushioning material for hot pressing according to an embodiment of the present invention.
2 is a schematic diagram showing an example of a state of use of a cushioning material for hot pressing according to an embodiment of the present invention.
3 is a cross-sectional view of a cushioning material for hot pressing according to an embodiment of the present invention.
4 is a cross-sectional view of a cushioning material for hot pressing according to a modified example of the present invention.

Next, referring to the accompanying drawings, preferred embodiments of the present invention will be described in detail. 1 and 2 are schematic views showing an example of a use state of a cushioning material for hot pressing according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view of a cushioning material for hot pressing according to an embodiment of the present invention. In addition, in this specification and drawings, the same reference numerals are assigned to components having substantially the same functional configuration, and redundant description is omitted. In addition, sub-materials in each figure are appropriately emphasized for ease of explanation, and the size of the figure does not represent the actual size.

<1. heat press>

First, prior to the description of the cushioning material for hot pressing, an example of hot pressing using the cushioning material for hot pressing according to the embodiment of the present invention will be described. In addition, in this embodiment, it is explained that the object to be subjected to hot pressing is the laminated board 300 as a precursor of a printed wiring board.

As shown in FIG. 1, the heat press is performed by pressing the laminated plate 300 with a pair of upper and lower heated hot discs 100. Also, as shown in FIG. 1 , hot pressing may be performed on several laminated plates 300 at the same time.

As shown in FIG. 2, in the laminate 300, metal foil 302 such as copper foil is disposed on both sides of the prepreg 301. The prepreg 301 is constructed by laminating several plates in a semi-cured state in which glass cloth is impregnated with a thermosetting resin.

A mirror plate 200, such as a stainless plate, is disposed between the laminated plates 300 so that they do not come into direct contact with each other and at the same time form a surface. In addition, to avoid direct contact with the cushioning material 1 for heat press and the hot plate 100 at the top and bottom of the laminated plate 300 present at the top and bottom of the laminated plate 300 present at the top, and at the same time to form the surface. The mirror plate 200 is disposed for this.

Then, the object to be pressed, in which the laminated plate 300 and the mirror plate 200 are laminated, is pressed by the hot disc 100 through the cushioning material 1 for hot pressing disposed above and below the laminated plate 300 . Here, the cushion material 1 for hot pressing has appropriate thermal conductivity, deformation followability, and cushioning properties, and the pressure and heat in the hot plate 100 are uniformly applied to the object to be pressed in which the laminated plate 300 and the mirror plate 200 are laminated. It has a conveying function.

Existing cushioning materials for hot pressing have problems in conveyance due to automatic stacking, peelability with a hot plate, and fluff during use, but the cushioning material for hot pressing according to the present embodiment 1 prevents these problems as shown below. can do.

<2. Cushion Material for Heat Press>

Next, the cushioning material for hot pressing according to the present embodiment will be described.

The cushioning material 1 for hot press shown in FIG. 3 is used for manufacture of the electric component which has laminated structure, such as a printed wiring board, for example, more specifically, for molding press. A cushioning material 1 for hot pressing includes a base material 10, a first batt fiber layer 20 disposed on one main surface (first main surface) of the base material 10, and the other main surface (second main surface) of the base material 10. 2 main surface) and an airtight sheet layer 40 disposed on the side opposite to the substrate 10 side of the second batt fiber layer 30.

The base material 10 is the main body of the cushioning material 1 for hot pressing, and is a layer that exhibits basic performance as the cushioning material 1 for hot pressing, such as thermal conductivity, deformation followability, and cushioning properties. The substrate 10 has a ground fabric 12 and a felt layer 14.

The base fabric 12 is a fiber-reinforced substrate that contributes to maintenance of tensile strength and stability of shape in the cushioning material 1 for hot pressing. Although not particularly limited, the base fabric 12 may be made of, for example, a woven fabric or grid-like material. In addition, when the base fabric 12 is a woven fabric, the structure of the woven fabric is not particularly limited, and plain fabric, twill weave, satin, or multiple weave using these may be used. As the lattice material, for example, warp and weft yarns overlapping each other can be used. As the constituent material of the base fabric 12, for example, meta-aromatic polyamide, para-aromatic polyamide, wholly aromatic polyester fiber, poly-p-phenylenebenzobisoxazole (PBO) fiber, A stainless fiber etc. can be selected suitably. In addition, the base fabric 12 can be omitted suitably according to the specification of the cushioning material 1 for hot pressing.

A felt layer 14 is disposed on both sides of the base fabric 12 . The felt layer 14 is a fiber aggregate layer formed by bonding short fibers together, and exhibits basic performance as a cushioning material 1 for hot pressing, such as thermal conductivity, deformation following property, cushioning property, etc. in the cushioning material 1 for hot pressing.

The felt layer 14, for example, arranges a fiber web made of batt fibers as short fibers on the base fabric 12, bonds them to each other by needle punching, and bonds to the base fabric 12 at the same time is formed by

The material constituting the felt layer 14 is not particularly limited, but is preferably made of a resin material having heat resistance, for example, an aromatic polyamide, for example, a meta-aromatic polyamide and/or a para-type material. Aromatic polyamides may be used. Specifically, staple fibers made of the above material may be used as batt fibers. That is, the felt layer 14 of the substrate 10 preferably contains aromatic polyamide fibers. More specifically, meta-aromatic polyamide fibers (Conex (trade name/Teijin) and nomex (trade name/Dupont)) mainly composed of poly-m-phenylene-isophthalamide, etc. , para-aromatic polyamide fibers (Kevlar (trade name/Dupont) and technora (trade name/Teijin)) mainly composed of poly-paraphenylene terephthalamide, etc., PPS fiber (tor-con (trade name) / Toray agent)) etc. can be used alone or in combination of 2 or more types.

The fiber length of the short fibers constituting the felt layer 14 is not particularly limited, but can be, for example, 38 to 130 mm. In addition, the fineness of the short fibers constituting the felt layer 14 is not particularly limited, but can be, for example, 0.8 to 11 dtex.

In addition, the weight per unit area of the felt layer 14 can be selected according to the use of the cushioning material 1 for hot pressing, and is not particularly limited. The total of the layers is 300-2700 g/m ² , preferably 1000-2200 g/m ² . Therefore, suitable thermal conductivity and strain followability can be obtained.

The first vat fiber layer 20 is disposed on one main surface of the substrate 10 and constitutes the surface layer of the cushioning material 1 for hot pressing. In addition, the first batt fiber layer 20 is usually disposed on the side surface in contact with the hot plate when the cushioning material 1 for hot pressing is used.

The first batt fiber layer 20 is formed by binding batt fibers by needle punching and simultaneously softening and smoothing the outer surface of the formed batt fiber layer. Accordingly, the outer surface 21 of the first vat fiber layer 20 is at least partially composed of fibers forming a flat shape along the outer surface 21 .

Such softening and smoothing may be performed by treating the batt fibers constituting the first batt fiber layer 20 at a temperature equal to or higher than the glass transition temperature. Further, in softening and smoothing, it is preferable to pressurize the outer surface 21 of the first vat fiber layer 20 with a hot plate or the like while maintaining the above temperature.

As the outer surface 21 is softened and smoothed in this way, the batt fibers in the vicinity of the outer surface 21 come into close contact with each other and adhere automatically or are embedded and adhered to the space formed by other fibers. This prevents the batt fibers from fluffing on the outer surface 21 . Furthermore, hair loss is prevented in the first vat fiber layer 20 .

In addition, the outer surface 21 of the first batt fiber layer 20 is appropriately densified by being softened and smoothed, thereby reducing the air permeability of the cushioning material 1 for hot pressing. Thereby, together with the airtight sheet layer 40 described later, the air permeability of the cushioning material 1 for hot pressing becomes sufficiently low, and the transportability of automatic stacking of the cushioning material 1 for hot pressing improves. Further, since the outer surface 21 is densified, the cushioning material 1 for hot pressing can be sucked, held, and conveyed by the suction device of the automatic loading device from the side of the first batt fiber layer 20.

On the other hand, even if the outer surface 21 of the first batt fiber layer 20 is smoothed, since it is composed of batt fibers, it has an appropriate surface roughness and has excellent peelability between the first batt fiber layer 20 and the hot plate. . Therefore, the cushioning material 1 for hot pressing is excellent in peelability with a hot disc.

The surface roughness Ra of the outer surface 21 of the first vat fiber layer 20 is not particularly limited, but is, for example, 2.5 to 11 μm, preferably 3 to 8 μm, and more preferably 4 to 7 μm. When the surface roughness Ra of the outer surface 21 of the first vat fiber layer 20 is equal to or greater than the lower limit, the hot press cushioning material 1 can have even better releasability from the hot plate. Further, if the surface roughness Ra of the outer surface 21 of the first vat fiber layer 20 is equal to or less than the above upper limit value, the transportability of the automatic stacking of the cushioning material 1 for hot pressing can be further improved. In addition, surface roughness Ra in this specification can be measured according to JIS-B0633.

Also, as described above, the outer surface 21 of the first batt fiber layer 20 is at least partially composed of batt fibers forming a flat shape along the outer surface 21 .

Here, the degree of flat shape of the batt fiber can be defined by the aspect ratio of the cross section of the batt fiber constituting the outer surface 21 . Specifically, the aspect ratio of the bat fibers when observing the cross section of the first batt fiber layer 20 in the thickness direction (diameter in the plane direction of the cushioning material 1 for hot pressing/diameter in the thickness direction of the cushioning material 1 for hot pressing) ) can be averaged.

The above aspect ratio is not particularly limited, but is, for example, 1.2 to 3.0, preferably 1.5 to 2.5.

In addition, the vat fibers constituting the first vat fiber layer 20 are not particularly limited as long as the above-described softening and smoothing can be performed, but, for example, unstretched fibers, preferably unstretched aromatic polyamide fibers, and more preferably unstretched fibers. New meta-aromatic polyamide fibers may be used. Such unstretched fibers are relatively easy to deform by the softening and smoothing treatment compared to fibers that have undergone a drawing treatment, and are advantageous in forming the outer surface 21 as described above.

Further, as batt fibers, in addition to the unstretched fibers described above, fibers subjected to a stretching treatment may be used. Such fibers include various fibers that can be used for the felt layer 14 described above. In this case, the weight ratio of unstretched fibers in the first vat fiber layer 20 is, for example, 70% by mass or more, preferably 80% by mass or more, and more preferably 100% by mass.

The fineness (average) of the vat fibers constituting the first vat fiber layer 20 is not particularly limited, but is, for example, 0.8 to 11 dtex, preferably 2 to 6 dtex. When the fineness of the batt fiber is equal to or greater than the lower limit, the outer surface 21 after the softening and smoothing treatment can be further smoothed. On the other hand, when the fineness of the batt fibers is less than the above upper limit, the number of fibers can be increased and the outer surface 21 can be made dense.

The weight per unit area of the first vat fiber layer 20 is not particularly limited, but is, for example, 80 to 200 g/m ² , preferably 100 to 150 g/m ² . When the weight per unit area of the first bat fiber layer 20 is equal to or less than the lower limit, the first bat fiber layer 20 is easily affected by the surface shape of the substrate 10 depending on the material configuration of the cushioning material 1 for hot pressing. , As a result, the surface smoothness of the first vat fiber layer 20 may deteriorate. On the other hand, if the weight per unit area of the first batten fiber layer 20 exceeds the above upper limit, the first batt fiber layer 20 hardly contributes to the cushioning properties, so depending on the configuration of the cushioning material 1 for hot pressing, the weight per unit area Compared to the case without the first vat fiber layer 20, cushioning properties may be lowered.

In addition, as shown in FIG. 2, the cushioning material 1 for hot pressing is usually arranged so that the outer surface 21 of the first batt fiber layer 20 on the side of the hot plate 100 faces each other. Thereby, it can be made excellent in the peelability between the hot disc 100 and the cushioning material 1 for hot presses.

The second vat fiber layer 30 is disposed on the main surface of the substrate 10 opposite to the first vat fiber layer 20 side. The second batt fiber layer 30 is formed by bonding batt fibers by needle punching.

Batt fibers constituting the second batt fiber layer 30 are not particularly limited, but the aforementioned unstretched fibers and various fibers that can be used for the aforementioned felt layer 14 can be used. In particular, when the second batt fiber layer 30 includes unstretched fibers as batt fibers, preferably unstretched aromatic polyamide fibers, more preferably unstretched meta-aromatic polyamide fibers, an airtight sheet layer described later Adhesion is further enhanced.

The fineness (average) of the vat fibers constituting the second vat fiber layer 30 is not particularly limited, but is, for example, 0.8 to 11 dtex, preferably 2 to 6 dtex.

The weight per unit area of the second vat fiber layer 30 is not particularly limited, but is, for example, 80 to 200 g/m ² , preferably 100 to 150 g/m ² .

One of the reasons for arranging the second batt fiber layer 30 is to prevent the occurrence of warping of the cushioning material 1 for thermal pressing due to repeated use. That is, when the cushioning material 1 for hot pressing is used, a difference in shrinkage occurs between the first batt fiber layer 20 side and the second batt fiber layer 30 side of the cushioning material 1 for hot pressing due to the heat of repeated press molding, Bending may occur in the cushioning material 1 for press. From the viewpoint of preventing the cushioning material 1 for hot pressing from warping, it is more preferable that the second bat fiber layer 30 has the same configuration as the first bat fiber layer 20.

The airtight sheet layer 40 is disposed on the opposite side of the second vat fiber layer 30 to the substrate 10 side. The airtight sheet layer 40 is composed of a fiber sheet or a resin film, so that it adheres to the second vat fiber layer 30, maintains high airtightness, and contributes to lowering the air permeability of the cushioning material 1 for hot pressing. Therefore, together with the airtightness of the outer surface 21 of the first batt fiber layer 20 described above, the cushioning material 1 for hot pressing is sucked into and maintained by the suction device even with a relatively weak suction force during automatic loading. That is, the cushioning material 1 for hot pressing is excellent in transportability during automatic loading.

The airtight sheet layer 40 is formed by heat-pressing or heat-sealing a fiber sheet or resin film to the second batt fiber layer 30. The fibrous sheet may be, for example, a paper-like sheet made of paper, that is, a wet-laid nonwoven fabric. Further, the material of the fibers constituting the fiber sheet is not particularly limited, but is preferably made of a resin material having heat resistance, such as an aromatic polyamide, such as a meta-aromatic polyamide and/or a para-aromatic polyamide. Polyamides may be used. The resin film is not particularly limited, but, for example, a fluorine-based resin film, specifically an ethylene-tetrafluoroethylene copolymer (ETFE), a tetrafluoroethylene/hexafluoropropylene copolymer (tetrafluoro ethylene/hexafluoro propylene copolymer (FEP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride, perfluoroalkoxy alkane; PFA), etc. can be used.

In addition, the surface roughness Ra of the airtight sheet layer 40 is not particularly limited, but is, for example, 2 to 7 µm, preferably 4 to 6 µm. Then, when the outer surface 41 of the fibrous sheet layer 40 is sucked into the aspirator as a suction surface in the case of an automatic stacking device, the vacuum state of the aspirator and the outer surface 41 can be well maintained.

The basis weight of the airtight sheet layer 40 is not particularly limited, but is, for example, 40 to 80 g/m ² , preferably 50 to 70 g/m ² .

The thickness of the airtight sheet layer 40 is not particularly limited, but is, for example, 25 to 200 μm, preferably 50 to 100 μm.

The air permeability of the cushioning material 1 for hot pressing having the above structure according to the Frazier shape specified in JIS L 1096 is not particularly limited, but is, for example, 1.0 cm ³ /cm ² /sec or less, preferably 0.2 cm ³ /cm ² /sec or less, more preferably 0.0 cm ³ /cm ² /sec. Then, the conveyance property of the automatic loading of the cushioning material 1 for hot pressing can be made even more excellent. The lower limit of the air permeability is not particularly limited, but may be, for example, 0 cm ³ /cm ² /sec. In addition, when the air permeability of the cushioning material for hot pressing is 0.3 cm ³ /cm ² /sec or more, problems may occur in automatic conveyance depending on the configuration of the automatic stacking device used.

In addition, although the density of the cushioning material 1 for hot press is not specifically limited, For example, it is 0.3-0.7 g/cm<3>, Preferably it is 0.4-0.6 g/cm< ³ >. For this reason, the thermal conductivity of the cushioning material 1 for hot pressing is stable during hot pressing from the beginning of use to the end of use (the difference in thermal conductivity change is small), and an excellent cushion is maintained.

In addition, although the thickness of the cushioning material 1 for hot press is not specifically limited, For example, it is 1-8 mm, Preferably it is 2-6 mm.

The dimensions of the cushioning material 1 for hot pressing are not particularly limited, and can be appropriately set depending on the purpose and the hot plate to be used.

In the above-described cushioning material for hot pressing 1, the outer surface of the first bat fiber layer 20 is softened and smoothed, thereby preventing the bat fibers from fluffing on the outer surface 21. On the other hand, since the first batt fiber layer 20 is composed of batt fibers, the cushioning material 1 for hot pressing is excellent in peelability from the hot plate.

In addition, since the cushioning material 1 for hot pressing has an airtight sheet layer 40, the air permeability of the cushioning material 1 for hot pressing is low, and the airtightness of the outer surface 21 of the first batt fiber layer 20 Together, the cushioning material 1 for hot pressing is sucked into and maintained by the suction machine even with a relatively weak suction force during automatic loading. That is, the cushioning material 1 for hot pressing is excellent in transportability during automatic loading. Further, the cushioning material 1 for hot pressing is excellent in conveyance even when it is automatically conveyed by performing suction not only from the outer surface 41 side but also from the outer surface 21 side. In particular, recently, cushioning materials for hot pressing generally tend to be lightweight, and therefore, even in an automatic stacking device, they tend to be attracted with a weaker suction force than before. For example, in Patent Document 1, suction is disclosed under conditions of 500 mmH ₂ O, but suction is currently performed at a vacuum degree of, for example, about 50 to 100 water column inches. In addition, suction is stopped after reaching a predetermined degree of vacuum according to the aspirator. Even in this case, it is possible that the cushioning material 1 for hot pressing can be easily sucked into and held by the aspirator of the automatic stacking device.

As mentioned above, the cushioning material 1 for hot press is used for manufacture of electrical components (laminated products) having a laminated structure, such as a printed wiring board, more specifically, for molding presses. For example, examples of laminated products are as follows. In addition, there are various products other than the examples shown below as laminated products.

(1) Laminate serving as a basal plate of a printed wiring board:

Examples of the laminate include a phenol laminate in which a layer made of kraft paper and phenol resin, a glass epoxy laminate in which a layer made of glass fiber fabric and an epoxy resin is made, and the like.

(2) Printed wiring board:

Examples of the printed wiring board include a single-sided printed wiring board in which a conductor pattern is formed on one side of the board, a double-sided printed wiring board in which a conductor pattern is formed on both sides of the board, and a multi-layer printed wiring board in which conductor patterns are formed not only on the outside but also inside the board. can

(3) flat panel display:

As a flat panel display, a liquid crystal display, electroluminescence, etc. are mentioned, for example.

(4) Semiconductor package:

As the semiconductor package, for example, a chip size package (CSP) having substantially the same size as a chip may be used.

In addition, the cushioning material for hot pressing according to the present invention can be used not only for the above-mentioned purposes but also for manufacturing materials having a laminated structure such as a laminated material, decorative board, and laminated material. In this case, the configuration of the cushioning material for hot pressing according to the present invention can be appropriately changed according to the use.

<3. Manufacturing method of cushion material for hot press>

Next, the method for manufacturing the cushioning material 1 for hot pressing described above according to the present invention will be described as an example.

A method for producing a cushioning material for hot pressing according to the present invention includes the steps of disposing batt fibers on at least one main surface of a substrate and performing needling to form a batt fiber layer on at least one main surface of the substrate to obtain a laminated board; A step of pressing at a temperature equal to or higher than the glass transition temperature of the vat fiber in a state where an airtight sheet is disposed on the other main surface side of the substrate along the laminate.

In this embodiment, first, the base material 10 is prepared prior to the step of obtaining the laminate. The base material 10 is formed by arranging a fiber web made of bat fibers as single fibers in the above-described base fabric 12 on the base fabric 12, bonding them to each other by needle punching, and bonding to the base fabric 12 at the same time. Felt layer (14) can be obtained by forming

In the next step, vat fibers are placed on both sides of the substrate 10 and needling is performed to form vat fiber layers 20 and 30 on both surfaces of the substrate 10 to obtain a laminate. Specifically, batt fibers are placed on one main surface of the base material 10 and needling is performed, and then batt fibers are placed on the other main surface of the base material 10 and needling is performed, sequentially forming the first batt. A fibrous layer (20) and a second vat fiber layer (30) are obtained. In addition, either of the first batt fiber layer 20 and the second batt fiber layer 30 may be formed first.

The next step is to construct the first batt fiber layer 20 in a state where an airtight sheet is placed on the main surface of the obtained laminate on the opposite side of the first vat fiber layer 20, that is, on the second vat fiber layer 30. Press at a temperature above the glass transition temperature of the vat fibers. Accordingly, the airtight sheet adheres to the second fiber layer 30 to form the airtight sheet layer 40, and at the same time, the outer surface 21 of the first batt fiber layer 20 is softened and smoothed.

The press temperature is not particularly limited as long as it is a temperature equal to or higher than the glass transition temperature of the batt fibers constituting the first batt fiber layer 20, but is preferably a decomposition temperature equal to or higher than the glass transition temperature of the batt fibers constituting the first batt fiber layer 20 or below the melting temperature. Specifically, the press temperature is, for example, 270 to 330°C, preferably 280 to 300°C.

The press pressure is not particularly limited, but is, for example, 5 to 40 kg/cm ² , preferably 10 to 20 kg/cm ² , from the viewpoint of stabilizing thermal conductivity and maintaining cushioning properties when using the cushioning material 1 for hot pressing. .

The press time is not particularly limited and can be set appropriately, but is, for example, 10 to 40 minutes, preferably 15 to 25 minutes.

Through the above steps, the cushioning material 1 for hot pressing can be obtained. Further, the obtained cushioning material 1 for hot pressing can be appropriately cut according to the application, and post-processing such as washing can be performed.

<4. Variation>

Next, a modified example of the above-described cushioning material 1 for hot pressing will be described. 4 is a cross-sectional view of a cushioning material for hot pressing according to a modified example of the present invention. In the cushioning material 1 A for hot pressing shown in FIG. 4, the second vat fiber layer 30 is omitted, and the airtight sheet layer 40 is formed directly on the main surface of the substrate 10 opposite to the first vat fiber layer 20 side. It is different from the cushioning material 1 for hot press in that it is arrange|positioned at.

Also in this modification, since the cushioning material 1 A for hot pressing includes the first vat fiber layer 20 as described above, fluffing of vat fibers is prevented and the release property from the hot plate is excellent. The cushioning material for hot pressing (1) has an airtight sheet layer (40), so that the outer surface (21) of the first vat fiber layer (20) has airtightness and transportability during automatic stacking is excellent.

In addition, as described above, the second batt fiber layer 30 is mainly disposed to suppress bending when the cushioning material 1 for hot pressing is used. Therefore, the cushioning material for hot pressing (1) A is suitable for cases where warpage is not a problem and when it has a structure in which warpage is suppressed by the material composition of each layer even when the second vat fiber layer is omitted.

The cushioning material for hot pressing (1) A can be manufactured in the same way as the cushioning material for hot pressing (1), except that the formation of the second vat fiber layer 30 is omitted in the step of obtaining the laminate. That is, during pressing, an airtight sheet is disposed on the main surface of the laminate on the opposite side to the first vat fiber layer 20. In this case, in order to strengthen the bond between the base material 10 and the airtight sheet layer 40, an adhesive may be disposed between the base material 10 and the airtight sheet layer 40 to bond them to each other.

[Example]

Hereinafter, the present invention will be described in more detail by examples, but the present invention is not limited by these examples.

<1. Manufacture of cushioning materials for hot pressing>

(1) Preparation of materials

First, as a base fabric, a woven fabric in which warp and weft are composed of meta-aromatic polyamide fibers (m-aramid fibers) (yarn fineness: 2/20S (20th span yarn twisted), texture: 1 /1 plain weave, weight per unit area: 100 g/m ² ) was prepared. Subsequently, m-aramid fibers (fineness: 2.2 dtex, fiber length: 51 mm) were laminated with a total unit area weight of 900 g/m ² on both sides, and a substrate having felt layers on both sides of the woven fabric was prepared.

(2) formation of vat fiber layer

Next, unstretched m-aramid fibers (fiber length: 51 mm, glass transition temperature: 270 ° C.) of the fineness shown in Table 1 were prepared as bat fibers for the first and second batt fiber layers, and on both sides of the substrate per cross-section First and second batten fiber layers having a unit area weight of 150 g/m ² were formed, and a laminate having the first and second batt fiber layers on both sides was obtained. In Example 5, the second vat fiber layer was not formed.

In addition, formation of the first and second batt fiber layers was carried out by arranging the batt fibers as a pre-bat fiber layer on a substrate and integrating the substrate and the pre-bat fiber layer by needling.

(3) Press

Next, pressing is performed with aramid paper (m-aramid paper, thickness: 178 μm) placed on the second batt fiber layer, and the aramid paper is adhered to the second batt fiber layer as an airtight sheet layer while simultaneously adhering the first batt A softening and smoothing treatment was performed on the outer surface of the fibrous layer. Press conditions are as shown in Table 1. Further, in Example 5, instead of aramid paper, an ethylene-tetrafluoroethylene copolymer film (ETFE film, thickness: 50 μm) was placed on the side opposite to the first vat fiber layer of the substrate and pressed. Also, in Comparative Example 1, pressing was performed without disposing aramid paper on the second vat fiber layer. In Comparative Example 3, aramid paper was placed on both sides of the laminate and pressed. From the above, cushioning materials for hot pressing according to Examples 1 to 5 and Comparative Examples 1 to 3 were obtained.

<2. evaluation>

(1) surface roughness

The surface roughness Ra of the outer surface of the first vat fiber layer was measured according to JIS-B0633 with respect to the cushioning material for hot pressing of each Example and each Comparative Example using a surface roughness contour measuring instrument (Surf com 480A: manufactured by Tokyo Seimitsu Corporation). did. The results are shown in Table 1. In addition, the cushioning material for hot pressing according to Comparative Example 3 in the table shows the surface roughness of the airtight sheet disposed on the first vat fiber layer.

(2) air permeability

For the cushioning material for hot press of each Example and each Comparative Example, the air permeability according to the Frazier shape specified in JIS L 1096 was measured using an air permeability meter (Frazier permeameter: manufactured by Tokyo Seimitsu Corporation). In addition, in the air permeability measurement, the suction surface was set to the first vat fiber layer side. The results are shown in Table 1. In the table, the values in parentheses are actually measured air permeability, and the values without parentheses are actually measured air permeability values displayed according to the display method specified in JIS L 1096.

(3) Aspect ratio of batt fibers

A cross section of the outer surface of the first batt fiber layer was observed with a scanning electron microscope, and the aspect ratio of the batt fibers constituting the outer surface of the first batt fiber layer (diameter in the plane direction of the cushioning material for hot pressing/thickness direction of the cushioning material for hot pressing) diameter) was measured. The results are shown in Table 1.

(4) fluff

For the cushioning materials for hot pressing of each Example and each Comparative Example, short fibers protruding from the surface of the first batt fiber layer were observed using a microscope (digital microscope VHX-900, manufactured by Keyence Corporation). At this time, short fibers of 0.5 mm or more in length protruding from the surface of the first vat fiber layer or short fibers protruding in a loop were evaluated as "B", and others were evaluated as "A". The results are shown in Table 1.

(5) Peelability

With respect to the cushioning material for hot pressing of each Example and each comparative example, in the hot press device in which a stainless plate (SUS plate) is installed on the upper hot disc and the lower hot disc is pressed by the vertical movement of the upper hot disc, the hot press A hot press cushioning material is placed between the SUS plate and the lower heating plate so that the surface of the first batt fiber layer of the cushioning material is in contact with the SUS plate, and hot-pressing is performed (press conditions: 220°C-40 kg/cm ² -60 minutes) and then opened the press. At this time, the time until each cushion member naturally peels off from the SUS plate was measured, and a time of 3 seconds or less was evaluated as "A", and a time exceeding 3 seconds was evaluated as "B". The results are shown in Table 1.

(6) Returnability

The cushioning materials for hot pressing of each Example and each comparative example were sampled at a diameter of 100 mm, and a silicone rubber sucker having a diameter of 50 mm was adsorbed to the center of the surface of the first batt fiber layer of each cushioning material for hot pressing. Subsequently, the cushioning material for each hot press was lifted through the sucker. At this time, those in which the cushioning material for hot pressing was lifted were evaluated as "A", and those in which the cushioning material for hot press was not lifted were evaluated as "B". The results are shown in Table 1.

manufacturing conditions Composition of cushion material for hot press evaluation Fineness of Batt Fiber
(dtex) press conditions 1st bat
fiber layer Presence or absence of airtight sheet layer ventilation
(cm ³ /cm ² /sec) fluff exfoliation transportability temperature
(℃) pressure
(kg/cm ² ) hour
(minute) Surface roughness RA of the outer surface
(μm) Aspect Ratio of Batt Fiber 1st vat fiber layer side Second vat fiber layer side Example 1 0.8 290 10 15 2.5 1.6 radish you 0.0
(0.03) A A A Example 2 3.0 290 10 15 4.2 2.0 radish you 0.0
(0.04) A A A Example 3 5.6 290 10 15 6.3 1.9 radish you 0.0
(0.04) A A A Example 4 11 290 15 20 10.1 1.3 radish you 0.1
(0.06) A A A Example 5 3.0 290 10 15 4.2 2.0 radish you 0.0
(0.04) A A A Comparative Example 1 3.0 290 10 15 4.4 2.0 radish radish 0.8 A A B Comparative Example 2 3.0 240 10 15 15.8 1.1 radish you 1.8 B A B Comparative Example 3 3.0 290 10 15 1.2 - you you 0.0
(0.02) A B A

As shown in Table 1, the cushioning materials for hot pressing according to Examples 1 to 5 suppressed fuzzing of the batt fiber layer and had excellent peelability and transportability. In contrast, the cushioning material for hot pressing according to Comparative Example 1 did not have an airtight sheet layer and thus had insufficient transportability. Further, in the cushioning material for hot pressing according to Comparative Example 2, as a result of performing the press treatment at a temperature lower than the glass transition temperature of the batt fiber, the softening and smoothing treatment was not sufficiently performed. Therefore, the cushioning material for hot pressing according to Comparative Example 2 could not suppress fluffing of batt fibers, and also had high air permeability and poor transportability.

In addition, in the cushioning material for hot pressing according to Comparative Example 3, as a result of disposing the airtight sheet layer on the first batt fiber layer, the outer surface of the first batt fiber layer was not softened and smoothed, and the first batt fiber layer was not exposed to the outer surface. . As a result, the cushioning material for hot pressing according to Comparative Example 3 could not have proper outer surface irregularities derived from the first vat fiber layer, and had poor peelability.

In the above, preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to these examples. It is clear that those of ordinary skill in the technical field to which the present invention belongs can consider various changes or modifications within the scope of the technical idea described in the claims, and these are naturally considered to fall within the technical scope of the present invention. I understand.

1, Cushion material for 1A heat press
10 base material
12 ground fabric
14 felt layer
20 first vat fiber layer
21 outer surface
30 second vat fiber layer
40, 40A airtight sheet layer
41 outer surface
100 heat board
200 mirror plate
300 laminate
301 prepreg
302 metal foil

Claims (11)

a base material; and
A bat fiber layer disposed on the first main surface of the substrate and having an outer surface softened and smoothed;
A cushioning material for hot pressing, which has an airtight sheet layer disposed only on the second main surface side of the base material.
The cushioning material for hot pressing according to claim 1, wherein the batt fiber layer includes batt fibers and is softened and smoothed at a temperature equal to or higher than the glass transition temperature of batt fibers.
equipment and
a vat fiber layer disposed on the first major surface of the substrate;
having an airtight sheet layer disposed only on the second main surface side of the substrate;
The outer surface of the batt fiber layer is at least partially composed of fibers forming a flat shape along the outer surface.
The cushioning material for hot pressing according to any one of claims 1 to 3, wherein the airtight sheet layer is composed of a fiber sheet or a resin film.
The cushioning material for hot pressing according to any one of claims 1 to 3, wherein the outer surface of the batt fiber layer has a surface roughness Ra of 2.5 to 11 µm.
The cushioning material for hot press according to any one of claims 1 to 3, wherein the air permeability in the form of a Frazier specified in JIS L 1096 is 0.2 cm ³ /cm ² /sec or less.
The cushioning material for hot pressing according to any one of claims 1 to 3, wherein the batt fiber layer contains unstretched meta-aromatic polyamide fibers.
The cushioning material for hot pressing according to any one of claims 1 to 3, wherein the fineness of the vat fibers constituting the vat fiber layer is 0.8 to 11 dtex.
The cushioning material for hot pressing according to any one of claims 1 to 3, further comprising a vat fiber layer disposed between the substrate and the airtight sheet layer.
The cushioning material for hot pressing according to any one of claims 1 to 3, wherein the substrate contains aromatic polyamide fibers.
A step of disposing batt fibers on at least one main surface of a substrate, performing needling, and forming a batt fiber layer on at least one main surface of the substrate to obtain a laminate;
A method for producing a cushioning material for hot pressing, comprising a step of performing pressing at a temperature equal to or higher than the glass transition temperature of the batt fiber in a state in which an airtight sheet is disposed only on the other main surface side of the substrate in the laminate.

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