TW201302418A - Molding press for cushioning material - Google Patents

Abstract

The present invention provides a molding press as with the cushioning material has excellent function, especially excellent buffer property and attaching the effect of preventing the cushioning material. Further A molding press for buffering material, it is disposed on the one or more felt layer,in the felt layer disposed on the two outer peripheral surface of the heat resistant cloth (e g a glass cloth ), thereby the heat resistant cloth two outer circumferential surface disposed on the mesenteria tetrafluoroethylene may be employed as the material layer is formed.

Description

Forming and pressing cushioning material

The present invention relates to a cushioning material which is a cushioning material for forming press used in a step of manufacturing a precision equipment component such as a copper laminate, a flexible printed circuit board or a ceramic laminate (hereinafter sometimes abbreviated as a cushioning material). And has excellent cushioning properties.

A product (laminated product) having a laminated structure can be sandwiched between a plurality of hot plates, for example, by using hot pressing of the hot plate.

One of the laminates produced by this method is as follows. Further, in the laminated product, in addition to the examples shown below, various products are also available.

(1) A laminate which becomes a substrate of a printed wiring board

Examples of the laminate include a paper phenol laminate including kraft paper and a phenol resin, a glass fiber woven fabric, and an epoxy resin laminated glass sheet.

(2) Printed wiring board

The laminated board has a single-sided printed wiring board in which a conductor pattern is formed on one surface of the substrate, and a double-sided printed wiring board in which a conductor pattern is formed on both surfaces of the substrate, and is formed not only on the outer surface of the substrate but also inside. A multilayer printed wiring board of a conductor pattern or the like.

(3) Flat panel display: There are liquid crystal displays, electroluminescent displays, and the like.

(4) Semiconductor package: A chip size package (CSP) or the like having substantially the same size as the wafer.

In the step of producing the various laminated products (molded bodies) by the forming press, a cushioning material is interposed between the hot plate and the laminated product. The cushioning material has a cushioning property so that the hot plate does not directly abut against the laminated product, and functions to uniformly conduct heat generated by the hot plate to the entire surface of the laminated product.

A specific use example of the cushioning material will be described based on Fig. 1 .

Fig. 1 is a cross-sectional view showing an example of forming press of a laminated board in a manufacturing apparatus of a double-sided printed wiring printed board. In the forming press apparatus shown in Fig. 1, one of the opposing pairs of the hot plate 40 and the pair of hot plates 40 is disposed on the inner side of the pair of cushioning members C and the pair of cushioning members C. One of the mirror panels 50, the copper foil 60, and the prepreg 70 are disposed.

Finally, a double-sided printed wiring board (laminated product) is formed by the prepreg 70 and the copper foil 60. The prepreg 70 is formed by laminating a plurality of sheets which are impregnated with epoxy resin in a glass cloth and which are semi-cured.

In the molding press apparatus, heat is applied by applying heat and pressure to the hot plates 40 and 40. However, the molding conditions at this time differ depending on the blending of the epoxy resin raw materials and the like. Moreover, if the heat transfer amount (temperature rising rate: ° C/min) of the cushioning material used in the forming step does not satisfy the manufacturing conditions, the physical properties of the laminated product may be poor. Moreover, in order to manufacture a uniform laminated product, it is necessary to apply a certain pressure and heat, but the heat and pressure applied to the laminated board must be uniform over the entire surface of the cushioning material. In the configuration of Fig. 1, the cushioning material C of the flat plate is placed between the hot plate 40 and the prepreg 70 to be hot pressed. However, when the above-described hot pressing is repeated, the surface of the cushioning material that abuts against the hot plate 40 and/or the mirror panel 50 becomes too smooth, and the phenomenon that the cushioning material C is attached to the hot plate 40 and/or the mirror panel 50 can be seen. .

In particular, when the cushioning material is in the case of a needle punch type, the unevenness of the surface of the cushioning material (the unevenness of the needle hole of the knitting) is loosened by the use of the cushioning material, and the surface of the cushioning material is roughened. Since it is reduced and smoothed, the phenomenon that the cushioning material is attached to the hot plate 40 and/or the mirror panel 50 can be seen.

That is, as the number of times of repeated hot pressing (the number of times of forming press) increases, the surface of the cushioning material becomes smoother, so that the sticking phenomenon is further increased. If the cushioning material C is attached to the hot plate 40 and/or the mirror panel 50, the subsequent manufacture of the laminated product is hindered, and it is necessary to replace the cushioning material C.

However, commercially available cushioning materials are various types such as rubber, felt-like products (non-woven fabrics, etc.), laminated bodies of rubber and felt, and the like. Although recent efforts have been made to produce a uniform laminated product, a cushioning material that avoids the phenomenon that the cushioning material is attached to the hot plate and/or the mirror panel is required.

In the prior art, as a cushioning material for forming press, Patent Document 1 discloses a cushioning material which improves the cushioning property and heat transfer property by using the felt-like nonwoven fabric which is integrated by knitting as described above.

For example, as such a cushioning material, there is shown in FIG. In Fig. 2, the cushioning material C4 includes a base material 11B and two layers of felt fibers 11A knitted with staple fibers in the surface of the base 11B.

Here, the chemical fiber short fibers are composed of meta-aromatic polyamines and polyfluorene fibers. Further, the base 11B is a woven fabric formed of a warp yarn 11B1 and a weft yarn 11B2 containing heat resistant fibers. When the cushioning material is used, even if there is a small amount of irregularities on the printed circuit board, it can be made uniform to a certain extent and pressure is applied. However, if the cushioning material is used continuously, it is combined with the hot plate and / Or the uneven shape of the surface of the cushioning material against which the mirror panel abuts (the unevenness of the pinhole generated by knitting) becomes smooth, so that the phenomenon that the cushioning material is attached to the hot plate and/or the mirror panel can be seen.

In the prior art, the cushioning material for forming press is described in Patent Document 2, which includes a heat-resistant rubber and a glass cloth impregnated with a heat-resistant resin as a core material to bond the aluminum sheet to the surface. Layer of cushioning material. In the manufacturing process of the flexible printed circuit board, when the cover film having the polyimide film as the base material is pressure-bonded to the flexible substrate, the buffer material can be caused by the unevenness of the wiring portion. The void is generated, but even if the cushioning material is used, the surface of the cushioning material (the cover film made of the polyimide film) which abuts on the hot plate and/or the mirror plate is continuous with the cushioning material. It is smoothed by use, so that the phenomenon that the cushioning material C is attached to the hot plate and/or the mirror panel can be seen.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-145567

[Patent Document 2] Japanese Patent Laid-Open No. Hei 8-148814

In view of the above disadvantages, the present invention provides a cushioning material for forming press which has excellent cushioning properties as a cushioning material for forming press, and heat and pressure applied to the laminated sheet are uniform over the entire surface of the cushioning material, and are in contact with the hot plate. The surface of the cushioning material does not become too smooth, so the cushioning material is not attached to the hot plate and/or the mirror panel.

The present inventors have solved the above problems and have provided a cushioning material for forming press which has excellent cushioning properties and conducts heat uniformly to the entire surface.

(1) A cushioning material for forming presses, characterized in that it has at least one layer of felt layers, and a heat-resistant cloth is disposed on both outer peripheral surfaces of the felt layer, and further on both outer peripheral surfaces of the heat-resistant cloth A tetrafluoroethylene film is disposed as a surface layer.

(2) The cushioning material for forming press according to the above (1), wherein a tetrafluoroethylene film is disposed between the felt layer and the heat-resistant cloth.

(3) The cushioning material for forming press according to any one of the above (1) to (2), wherein the felt layer is a chemical fiber of a chemical fiber short fiber or a meta-aromatic polyamine which uses a para-aromatic polyamine. Any one of short fibers or a felt layer of such a mixture of chemical fiber short fibers.

(4) The cushioning material for forming press according to any one of (1) to (3), wherein the heat-resistant cloth is a woven fabric of fibers selected from the group consisting of glass fibers, cerium oxide fibers, alumina fibers, and ceramic fibers. (cloth).

(5) The cushioning material for forming press according to the above (4), wherein the heat-resistant cloth has a thickness of 100 μm or more and 300 μm or less and a mass of 100 g/m ² to 300 g/m ² .

(6) The cushioning material for forming press according to the above (4), wherein the heat-resistant cloth has a thickness of 150 μm or more and 250 μm or less and a mass of 150 g/m ² to 250 g/m ² .

(7) The cushioning material for forming press according to any one of the above (1), wherein the tetrafluoroethylene film is selected from the group consisting of tetrafluoroethylene-ethylene copolymer (ETFE), and four A film of a vinyl fluoride-perfluoroalkyl vinyl ether copolymer (PFA), a tetrafluoroethylene-hexafluoropropylene copolymer (FEP), or a polytetrafluoroethylene (PTFE).

(8) The cushioning material for forming press according to any one of the above (1), wherein the cushioning material for forming press has a surface roughness (Ra) of 3 μm or more and 30 μm or less.

Here, the term "at least one or more layers of the felt layer" means one or two or more layers of heat-resistant chemical fiber short fibers having a fineness of 1.0 to 10.0 dtex, preferably a fineness of 1.0 to 6.0 dtex, to be knitted by the fibers. The felt layer formed by the entanglement between the two.

The felt layer may also comprise a woven or lattice-like material that becomes a matrix. It is preferably composed of a woven fabric obtained by weaving warp yarns and weft yarns containing heat-resistant fibers. In addition to the meta-aromatic polyamine and the para-aromatic polyamine, the yarn raw material may also be a wholly aromatic polyester fiber or poly-p-phenylenebenzobisoxazole (PBO, poly-p-phenylenebenzobisoxazole). ) Fiber, stainless steel fiber, etc.

In addition, the base material is preferably a woven fabric obtained by weaving warp yarns and weft yarns as described above. However, in addition to the woven fabric, a composition in which only warp yarns and weft yarns are superposed can be suitably used. Wait.

In the present invention, the joining between the felt layer and the heat-resistant cloth can be usually performed by bonding (bonding) with a heat-resistant resin, but a tetrafluoroethylene film can be disposed as a heat-resistant resin. In this case, the arrangement of the tetrafluoroethylene film functions as a bonding material between the felt layer and the heat-resistant cloth.

The chemical fiber short fiber (short fiber) is a chemical fiber short fiber and/or a meta-aromatic polyfluorene which is a para-aromatic polyamine which is a heat-resistant chemical fiber short fiber. In the case of the chemical fiber short fiber of the amine, the heat-resistant chemical fiber short fiber is blended with other chemical fiber short fibers, and the concept includes at least 50% by weight or more of the heat-resistant chemical fiber short fiber.

Specific examples of the heat-resistant chemical fiber short fibers include chemical fiber staple fibers of a para-aramid (Kevlar; trade name, manufactured by Dupont, Twaron; trade name / manufactured by Teijin), and/or meta-aromatic polyfluorene. A chemical fiber short fiber of an amine (Twaron; trade name, manufactured by Teijin, Nomex; trade name / manufactured by Dupont), or a staple fiber obtained by mixing various chemical fiber short fibers in a certain amount can be preferably used.

The heat-resistant fabric is a woven fabric (for example, a glass cloth) woven from glass long fibers having excellent heat resistance and strength and chemically stable, and a twill weave or a plain weave can be used. As the fiber material, fibers selected from glass fibers, cerium oxide fibers, alumina fibers, and ceramic fibers can be used. In the present invention, it is more preferred to use a glass cloth.

Further, the heat-resistant cloth may have a thickness in the range of 100 μm or more and 300 μm or less and a mass of 100 g/m ² to 300 g/m ² . More preferably, the heat-resistant cloth has a thickness of 150 μm or more and 250 μm or less and a mass of 150 g/m ² to 250 g/m ² .

The thickness of the cushioning material against the hot plate is too smooth to be attached to the hot plate and/or the mirror plate, and the thickness is 100 μm or more and the mass is 100 g/m ² or more. Heat resistant cloth is more advantageous. Further, in terms of uniformity of heat and pressure applied to the laminated sheet to the entire surface of the cushioning material, a heat-resistant cloth having a thickness of 300 μm or less and a mass of 300 g/m ² or less is advantageous.

The tetrafluoroethylene film is selected from the group consisting of tetrafluoroethylene-ethylene copolymer (ETFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and poly The film of tetrafluoroethylene (PTFE) is preferably one having a film thickness of 20 μm to 100 μm. It is preferable to set the film thickness to 20 μm or more in terms of preventing the unevenness of the heat-resistant cloth from being large on the surface of the cushioning material and making the heat and pressure applied to the laminated plate uniform over the entire surface of the cushioning material. Further, it is preferable to prevent the surface of the cushioning material that abuts against the hot plate from being excessively smooth, and to prevent the cushioning material from being attached to the hot plate and/or the mirror panel, the film thickness is preferably 100 μm or less.

When the constitution of the cushioning material of the present invention is explained by a layup on one side, it is a structure of a felt layer/heat-resistant cloth (for example, glass cloth)/tetrafluoroethylene film (surface material), and thus the felt layer It has a cushioning property for the temperature and pressure generated by the hot plate, and in order to prevent adhesion to the hot plate and/or the mirror panel, the surface unevenness of the heat-resistant cloth (for example, glass cloth) (the unevenness of the woven surface) is used as the surface layer. The above structure is useful because the surface of the tetrafluoroethylene film appears.

In the present invention, as a more preferable configuration, a laminate layer such as a felt layer/tetrafluoroethylene film/heat-resistant cloth (for example, glass cloth)/tetrafluoroethylene film (surface material) will be described. In the same manner, a tetrafluoroethylene film can be disposed between the felt layer and the heat-resistant cloth (for example, a glass cloth) as a bonding material. In other words, the structure is characterized in that a tetrafluoroethylene film is interposed on both outer peripheral surfaces of the felt layer to arrange a heat-resistant cloth (for example, a glass cloth), and a tetrafluoroethylene film is disposed on both outer peripheral surfaces of the heat-resistant cloth. Surface layer. The felt layer is bonded to a heat-resistant cloth (for example, a glass cloth) via a tetrafluoroethylene film. Also, in a heat-resistant cloth (such as glass) The outer peripheral surface of the cloth was also bonded to a tetrafluoroethylene film and disposed as a surface layer of a cushioning material.

When the laminated product (molded body) is subjected to hot press forming by using the cushioning material of the present invention, the heat and pressure applied to the laminated sheet are uniform over the entire surface of the cushioning material, and abutting against the hot plate or the mirror plate The surface of the cushioning material does not become too smooth, so the cushioning material is not attached to the hot plate and/or the mirror panel.

When the cushioning material of the present invention is used repeatedly in a forming press apparatus, the roughness (Ra) of the outer peripheral surfaces (inside) of the cushioning material is preferably from 3 μm to 30 μm. When the roughness (Ra) is 3 μm or more, it is preferable to prevent the surface of the cushioning material from becoming too smooth and attached to the hot plate or the mirror panel. Moreover, when the roughness (Ra) is 30 μm or less, the heat and pressure applied to the laminate are preferably uniform in the entire surface of the cushioning material.

The basic structure of the present invention is a cushioning material for forming presses, characterized in that it has at least one layer of felt layers, and a heat-resistant cloth is disposed on both outer peripheral surfaces of the felt layer, and further, two heat-resistant cloths are provided. A tetrafluoroethylene film is disposed on the outer peripheral surface as a surface layer.

Here, an embodiment of the present invention will be described based on Fig. 3 .

In Fig. 3, reference numeral 10 denotes a cushioning material of the present invention, in which a base 10B is disposed, a first felt layer 1A is disposed on a hot plate side surface 1E of the base 10B, and a second felt layer 1B is disposed on the opposite side thereof. A first heat-resistant cloth (for example, glass cloth) 1C is disposed on the outer peripheral surface of the felt layer 1A, and a second heat-resistant cloth (for example, glass cloth) 1D is disposed on the outer peripheral surface of the second felt layer 1B. The first felt layer 1A and the first heat-resistant cloth (For example, glass cloth) 1C bonding and joining of the second felt layer 1B and the second heat-resistant cloth (for example, glass cloth) 1D can be joined (bonded) by a heat resistant resin.

In addition, the first heat-resistant cloth (for example, glass cloth) 1C and the second heat-resistant cloth (for example, glass cloth) 1D are provided with a tetrafluoroethylene film P1 and P2 as the surface layer, respectively, on the outer peripheral surface thereof.

The cushioning material 10 is composed of a cushioning material surface 1E that abuts against the hot plate and a cushioning material surface 2E that abuts against the mirror panel.

In addition, the cushioning material 10 in FIG. 3 is joined to the base 10B by the first felt layer 1A and the second felt layer 1B. In the invention of Fig. 3, the short fibers of the heat-resistant short staple fibers are knitted on the outer peripheral surface of the base 10B, and the first felt layer 1A and the second felt layer 1B are joined to the base 10B, respectively. However, it is possible to use a felt layer in which one or more layers of short fibers of the heat-resistant chemical fiber short fibers are knitted in advance without using the base 10B.

On the other hand, in FIG. 3, the outer peripheral surfaces of the first heat-resistant cloth (for example, glass cloth) 1C and the second heat-resistant cloth (for example, glass cloth) 1D are configured such that the tetrafluoroethylene film P1 and P2 are disposed, but The tetrafluoroethylene film can be joined to the outer peripheral surfaces of the first heat-resistant cloth (for example, glass cloth) 1C and the second heat-resistant cloth (for example, glass cloth) 1D by hot pressing at a melting temperature or higher.

Further, another embodiment of the present invention will be described based on Fig. 4 .

In Fig. 4, reference numeral 20 denotes a cushioning material of the present invention, in which a base 10B is disposed, a first felt layer 21A is disposed on a hot plate side surface 1E of the base 10B, and a second felt layer 21B is disposed on the opposite side thereof. In the outer peripheral surface of the felt layer 21A, the first heat-resistant cloth (for example, glass cloth) 21C is disposed via the tetrafluoroethylene film P3, and the outer surface of the second felt layer 21B is interposed with the tetrafluoroethylene film P4. 2 Heat-resistant cloth (for example, glass cloth) 21D.

In the first heat-resistant cloth (for example, glass cloth) 21C and the second heat-resistant cloth (for example, glass cloth) 21D, tetrafluoroethylene-based films P1 and P2 are disposed on the outer peripheral surface thereof as a surface layer.

The cushioning material 20 is composed of a cushioning material surface 1E that abuts on the hot plate and a cushioning material surface 2E that abuts against the mirror panel.

Further, the cushioning material 20 in Fig. 4 is joined to the base 10B by the first felt layer 21A and the second felt layer 21B. In the invention of Fig. 4, the short fibers of the heat-resistant short staple fibers are knitted on the outer peripheral surface of the base 10B, and the first felt layer 21A and the second felt layer 21B are joined to the base 10B, respectively. However, it is possible to use a felt layer in which one or more layers of short fibers of the heat-resistant chemical fiber short fibers are knitted in advance without using the base 10B.

On the other hand, in FIG. 4, the outer peripheral surfaces of the first felt layer 21A and the second felt layer 21B are configured such that the tetrafluoroethylene films P3 and P4 are disposed.

The tetrafluoroethylene film can be joined to the outer peripheral surfaces of the first felt layer 21A and the second felt layer 21B by hot pressing at a temperature higher than the melting temperature.

Alternatively, two sheets of the tetrafluoroethylene film may be previously press-bonded to the outer peripheral surfaces of the heat-resistant cloth (for example, glass cloth) to bond the glass cloth to the outer peripheral surface of the felt layer.

Example

Hereinafter, the cushioning material for forming press of the present invention will be described in more detail by way of examples, but the examples are not intended to limit the invention.

First, in the examples and comparative examples, the following configurations were used in common.

(1) The substrate disposed on the buffer material:

‧Weaving a woven fabric of spun yarn of a meta-aromatic polyamide (containing a spun yarn of 50 mm cut length of 6 dtex). Further, as a specific fiber, Twaron (trade name / manufactured by Teijin) was used. The quality of the weaving is 200 g/m ² .

(2) Conditions for knitting

‧The production of the felt layer; on the outer peripheral surface (the surface) of the above-mentioned woven fabric, the chemical fiber short fiber of Kevlar (trade name / manufactured by Dupont), which is a para-aramid, is used, that is, 2 dtex (dtex) A short fiber of 50 mm cut length was provided with a felt layer by using a needle of 6 barbs per rib and setting the number of knitting times to 50 times/cm ² . Therefore, a felt layer having a total mass of 700 g/m ^{2 was obtained} in accordance with the mass of the woven fabric of 200 g/m ² , the surface side felt mass of 250 g/m ² and the inner side felt mass of 250 g/m ² .

‧ After performing the above-mentioned knitting, a chemical fiber short fiber of Twaron (trade name / manufactured by Teijin), which is a meta-aromatic polyamine, is used on the outer peripheral surface (front and back) of the felt layer, that is, 2 dtex (dtex) The short fiber having a length of 50 mm was cut, and the number of knitting times was set to 50 times/cm ² using a hook of 6 knurls per rib, and an additional felt layer was provided. The additional felt layer based on the surface side of the additional mass of 150 g / m ² and to the back side of the additional mass of 150 g / m ² make up a total mass of 1000 g / m ² of the felt layer.

‧ After performing the above-mentioned knitting, the outer peripheral surface (front and back) of the felt layer is further formed into a knitting machine by using a needle having 18 hooks per two ribs and setting the number of knitting times to 80 times/cm ^{2 to form the present} invention. The felt layer (total mass 1000 g/m ² ).

(Example 1)

A fluororubber-based adhesive is applied to the outer peripheral surfaces (front and back) of the felt layer, and then a glass cloth is bonded to the front and back surfaces thereof as a heat-resistant cloth, and a tetrafluoroethylene film is placed on the front surface thereof as a surface layer. The cushioning material for forming press of Example 1. Further, the details of the tetrafluoroethylene film and the glass cloth and the processing conditions after the arrangement are as follows.

‧ tetrafluoroethylene film (surface material); tetrafluoroethylene-hexafluoropropylene copolymer (FEP), thickness 25 μm.

‧ glass cloth; mass 200 g / m ² , thickness 200 μm.

Processing conditions; the above-mentioned press-forming cushioning material was subjected to hot pressing at 280 ° C for 20 minutes under a pressure of 10 kg / cm ² .

(Example 2)

A cushioning material for forming press of Example 2 was produced under the same conditions except that a tetrafluoroethylene film (FEP) having a thickness of 25 μm was placed as a bonding material instead of the fluororubber-based adhesive of Example 1.

(Example 3)

The cushioning material for forming press of Example 3 was produced under the same conditions except that the surface layer tetrafluoroethylene film (FEP) of Example 2 was changed to a thickness of 50 μm.

(Example 4)

The cushioning material for forming press of Example 4 was produced under the same conditions except that the surface layer tetrafluoroethylene film (FEP) of Example 2 was changed to a thickness of 100 μm.

(Example 5)

The cushioning material for forming press of Example 5 was produced under the same conditions except that the glass cloth of Example 2 was changed to a mass of 150 g/m ² and a thickness of 150 μm.

(Example 6)

The cushioning material for forming press of Example 6 was produced under the same conditions except that the glass cloth of Example 2 was changed to a mass of 250 g/m ² and a thickness of 250 μm.

(Example 7)

The cushioning material for forming press of Example 7 was produced under the same conditions except that the glass cloth of Example 2 was changed to a mass of 100 g/m ² and a thickness of 100 μm.

(Example 8)

The cushioning material for forming press of Example 8 was produced under the same conditions except that the glass cloth of Example 2 was changed to a mass of 300 g/m ² and a thickness of 300 μm.

(Example 9)

The cushioning material for forming press of Example 9 was produced under the same conditions except that the surface layer tetrafluoroethylene film of Example 2 was changed to a tetrafluoroethylene-ethylene copolymer (ETFE) having a thickness of 25 μm.

(Embodiment 10)

The surface layer tetrafluoroethylene film of Example 2 was changed to a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) having a thickness of 25 μm, and the heating temperature was changed to 315 ° C under the processing conditions. Otherwise, the cushioning material for forming press of Example 10 was produced under the same conditions.

(Example 11)

The surface layer tetrafluoroethylene film of Example 2 was changed to polytetrafluoroethylene (PTFE) having a thickness of 25 μm, and the heating temperature was changed to 330 ° C in the processing conditions. Otherwise, the cushioning material for forming press of Example 11 was produced under the same conditions.

(Comparative Example 1)

A tetrafluoroethylene film was placed as a surface layer in the surface of the felt layer, and a cushioning material for forming press of Comparative Example 1 was produced. Further, the tetrafluoroethylene film and the processing conditions after the arrangement are as follows.

‧ tetrafluoroethylene film (surface material); tetrafluoroethylene-hexafluoropropylene copolymer (FEP), thickness 25 μm.

Processing conditions; The press-forming cushioning material of Comparative Example 1 described above was subjected to hot pressing at 280 ° C for 20 minutes under a pressure of 10 kg/cm ² .

(Comparative Example 2)

A tetrafluoroethylene film having a thickness of 25 μm as a bonding material and a glass cloth were placed in the surface of the felt layer in this manner to prepare a cushioning material for forming press of Comparative Example 2. Further, the details of the tetrafluoroethylene film and the glass cloth and the processing conditions after the arrangement are as follows.

‧ tetrafluoroethylene film (bonding material); tetrafluoroethylene-hexafluoropropylene copolymer (FEP), thickness 25 μm.

‧ glass cloth; mass 200 g / m ² , thickness 200 μm.

Processing conditions; the above-mentioned press-forming cushioning material was subjected to hot pressing at 280 ° C for 20 minutes under a pressure of 10 kg / cm ² .

For the samples prepared in the examples and the comparative examples, the performance of the cushioning material was measured using a test machine having the same structure as that shown in Fig. 1. Further, the buffer material was kept at a temperature of 190 ° C and a pressure of 40 kg / cm ² for 60 minutes, and then cooled in a water bath for 15 minutes, and pressurized for 15 minutes, and the above operation was set to one cycle, and 300 cycles were repeated. The cycle was carried out, and the following measurement was performed for each press.

‧ Determination of the amount of buffer displacement (μm): The thickness of the cushioning material in the case of pressing at 0.2 kg under heating at 180 ° C and the case of pressing at 50 kg was measured. Further, the difference in thickness between 0.2 kg and 50 kg was obtained, and the amount of buffer displacement (μm) was used. In the evaluation, those with a buffer amount of 300 μm or more were set to “excellent”, those of 200 μm or more and less than 300 μm were set to “good”, and those of less than 200 μm were set to “bad”.

‧ Measurement of surface roughness (μm): The roughness (Ra) of the outer peripheral surface of the cushioning material was measured. For the evaluation, those having a roughness (Ra) of 3 μm to 30 μm were set as "appropriate", and those other than the above were set as "unsuitable".

‧ Whether the attachment is attached: Check whether it is attached to the hot plate or the mirror panel, or visually confirm the presence or absence of the attachment. If the unattached person is set to "excellent", it will be attached as "excellent" if it is peeled off for 5 seconds or less, and it will be "bad" if it is attached for 5 seconds or more.

The results of the performance of the cushioning material measured using the above test machine are shown in the table. Therefore, in the examples of the present invention, it was confirmed that the cushioning material has excellent cushioning properties and adhesion preventing effects.

In Comparative Example 1 in which the roughness (Ra) was less than 3 μm, the surface of the cushioning material became too smooth and attached to the hot plate and the mirror panel. Further, in Comparative Example 2 in which the roughness (Ra) exceeded 30 μm, the heat and pressure applied to the laminate were not uniform over the entire surface of the cushioning material.

1A, 1B, 21A, 21B‧‧‧ felt layers

1C, 1D, 21C, 21D‧‧‧ heat-resistant cloth

1E‧‧‧The hot plate side of the cushioning material

2E‧‧‧Surface of the mirror panel

10, 20‧‧‧ cushioning material

10B‧‧‧ substrate

P1, P2, P3, P4‧‧‧ tetrafluoroethylene film

Fig. 1 shows an example of forming press of a laminate.

Fig. 2 shows a prior art cushioning material for forming press.

Fig. 3 shows an example of the state of the cushioning material for forming press of the present invention.

Fig. 4 shows an example of other aspects of the cushioning material for forming press of the present invention.

1A, 1B‧‧‧ felt layer

1C, 1D‧‧‧ heat-resistant cloth

1E‧‧‧The hot plate side of the cushioning material

2E‧‧‧Surface of the mirror panel

10B‧‧‧ substrate

P1, P2‧‧‧ tetrafluoroethylene film

Claims (8)

A cushioning material for forming presses, characterized in that it has at least one layer of felt layers, and a heat-resistant cloth is disposed on both outer peripheral surfaces of the felt layer, and PTFE is disposed on both outer peripheral surfaces of the heat-resistant cloth. A vinyl film is used as the surface layer. The cushioning material for forming press according to claim 1, wherein a tetrafluoroethylene film is disposed between the felt layer and the heat-resistant cloth. The cushioning material for forming press according to any one of claims 1 to 2, wherein the felt layer is any one of a chemical fiber short fiber using a para-aromatic polyamide or a chemical fiber short fiber of a meta-aramid. Or those blended with chemical fiber staple fibers. The cushioning material for forming press according to any one of claims 1 to 3, wherein the heat-resistant cloth is a woven fabric (cloth) selected from the group consisting of glass fibers, cerium oxide fibers, alumina fibers, and ceramic fibers. The cushioning material for forming press according to claim 4, wherein the heat-resistant cloth has a thickness of 100 μm or more and 300 μm or less, and a mass of 100 g/m ² to 300 g/m ² . The cushioning material for forming press according to claim 4, wherein the heat-resistant cloth has a thickness of 150 μm or more and 250 μm or less, and a mass of 150 g/m ² to 250 g/m ² . The cushioning material for forming press according to any one of claims 1 to 6, wherein the tetrafluoroethylene film is selected from the group consisting of tetrafluoroethylene-ethylene copolymer (ETFE) and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. A film of PFA, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and polytetrafluoroethylene (PTFE). The cushioning material for forming press according to any one of claims 1 to 7, wherein the cushioning material for forming press has a surface roughness (Ra) of 3 μm or more and 30 μm or less.