JP4217489B2 - Deep drawn molded body for expansion joint and method for producing the same - Google Patents

Description

【００１９】
【表２】

【００２０】
表１から明らかなように、この発明の成形品では屈曲回数１，０００回から５０，０００回のいずれの場合でも異常は認められなかった。
【００２１】
また、引張り試験では、屈曲１，０００回から屈曲５０，０００回までの各段階での試験片はいずれも１．００ＫＮ／25ｍｍ以上で、実機に使用して全く問題の生じないものであることが分かった。
【００２２】
（比較例１）
実施例１と同様のフッ素樹脂シート（ＰＴＦＥ）と補強材のガラスクロスを用いて、ガラスクロスのよこ糸がフッ素樹脂シートの長さ方向と４５°の角度となるように重ね合わせ、この間に０．０１ｍｍの熱溶融性フッ素樹脂シート（ＰＦＡ）を挟み、これを温度３６０℃、圧力１７kgf/cｍ² 、保持時間１０ｍin で加圧加熱して、フッ素樹脂シートとガラスクロスの補強材を一体化した複合シートを得た。
【００２３】
この複合シートを実施例と同様に図３及び図４に示す成形型にセットした。複合シートの周囲は、成形型の縁部で固定プレートを用いて固定しなかった。この状態で図３に示すように雄型１６を矢印の方向に下降して雌型１２に嵌合し加熱して加圧成形をおこなった。成形は、加熱温度３６０℃、圧力４kgf/cｍ² 、保持時間１０ｍinで行った。成形後は冷却して脱型した。成形型の加熱、冷却は実施例と同様にしておこなった。これによって得られたフッ素樹脂シートとガラス繊維の一体成形品は、ひだが入って商品価値は認められないものであった。
【００２４】
【発明の効果】
この発明によると、補強材を一体化したフッ素樹脂の深絞りプレスの立体成形品であって、プレス成形時に補強材が破損されるようなことがないので、フッ素樹脂シートと補強材を一体化した高強度の深絞り成形体を得ることが出来るようになった。また、その製品は表面にひだがなく滑らかで商品価値でも優れたものであった。しかも、この発明の一体成形はプレス成形であるからコストの面でも優れたものである。従って、これを用いると例えば、火力発電所、原子力発電所、製鉄所、セメント工場、化学プラントなどの排煙・排ガス系統、換気装置系統等の各種ダクトにガス不透過性が確保される厚さのフッ素樹脂シートとガラスクロスなどの織物の補強材を一体化した柔軟性と耐屈曲性を付与された伸縮継手のコーナー部が、低コストでしかも簡便に作成することができるようになった。
【図面の簡単な説明】
【図１】この発明によって得られた一実施例の深絞り成形体の斜視図。
【図２】この発明の成形体の製造に用いる複合シートとその構成部材の構成を示す説明図。
【図３】この発明の成形体の製造に用いる一実施例の成形型に複合シートを配置したものの斜視図。
【図４】この発明の成形体の製造に用いる一実施例の成形型に複合シートを配置したものの分解図。
【図５】この発明の成形体の製造に用いる一実施例の成形型に雄型を嵌合したものの斜視図。
【図６】（Ａ）は図５のＹ−Ｙに沿う断面図、（Ｂ）は図５のＺ−Ｚに沿う断面図。
【図７】屈曲試験品のサイズを示す寸法図。
【図８】屈伸試験装置の斜視図。
【図９】従来の伸縮継手の斜視図
【符号の説明】
１…フッ素樹脂シート、２…補強材、３…複合シート、４…熱溶融性フッ素樹脂シート、１０…深絞り成形体、１２雌型、１３，１４…固定プレート、１５…支持点、１６…雄型、３０…屈伸試験装置、２２…架台、２３…一側の止め部、２４…固定部材、２５…他側の止め部、２６…摺動部材、２７…クランク軸、２８…駆動原、２９…レール。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a deep-drawn molded article for an expansion joint made of a composite sheet in which a reinforcing material such as a fluororesin sheet and glass cloth is integrated, and a method for producing the same.
[0002]
[Prior art]
Recently, the demand for fluororesins with excellent properties such as heat resistance, chemical resistance, electrical properties, and low friction properties has increased rapidly in various industrial fields, but on the other hand, the processability and moldability are difficult. It is well known that there are. For example, a thickness of 0.2-1. An expansion joint that integrates a 0 mm fluororesin sheet and a fabric reinforcement such as glass cloth is used. FIG. 9 shows a part of such a conventional expansion joint, a part of which is extracted on the upper right side of the figure, and its details are shown in a perspective view. This expansion joint can absorb displacement such as axial direction, twist, misalignment and the like, and is extremely excellent in flexibility and bending resistance.
[0003]
However, in order to obtain such an expansion joint, when the expansion joint has a square shape or a structure having a straight portion and a corner portion, the corner portion has the same durability and bending resistance as the straight portion. However, it was very difficult to achieve this. This is because, in the corner portion, if a composite sheet having the same plane as that of the straight portion is used, the displacement in the corner portion cannot be absorbed and complicated creases are generated. In order to solve this, it is preferable that the composite sheet has a circular arc in the corner portion or the like. That is, as the shape of the corner portion, it is preferable that the cross-sectional shape is a circular arc by deep drawing or the like, but it has been very difficult to produce such a molded body with a composite sheet.
[0004]
That is, in order to give strength and bending resistance to the fluororesin sheet to obtain a product as described above, a reinforcing material such as a fluororesin sheet and glass cloth is integrally formed through a heat-meltable fluororesin. The method has been adopted conventionally. However, since reinforcing materials such as glass cloth have a very small elongation compared to fluororesin, a sheet of reinforcing material such as a fluororesin sheet and glass cloth is deep drawn as the shape of the corner as described above. It has been very difficult to manufacture a molded product having an arc shape in cross section by molding or the like.
[0005]
Therefore, when manufacturing a three-dimensional product with a thin fluororesin, it is a method of scraping from a resin lump or dispersing the fluororesin in a dispersion medium, applying it to the mold surface that coincides with the corner, drying it, and firing it. However, the cutting method is very expensive because it takes man-hours and requires extra materials. In addition, the method of applying and drying a fluororesin dispersion on the surface of the latter mold and firing it will not only leave problems with thickness accuracy and gas impermeability of the sheet, but also with reinforcement such as glass cloth. It was also very difficult to integrate the materials. For this reason, conventionally, a composite sheet obtained by thermocompression bonding of a fluororesin sheet and a glass cloth is not particularly molded, but it has an extra length that can absorb displacement such as axial direction, twist, misalignment, etc. Although joints have been formed and used, it has been difficult to maintain a long life by causing local damage to the reinforcing material due to repeated vibration and torsion.
[0006]
[Problems to be solved by the invention]
In the present invention, when a composite sheet in which a fluororesin sheet and a fabric reinforcing material are stacked and integrated is press-molded with a molding die, the warp or weft of the fabric reinforcing material in the composite sheet is at least one side of a square-shaped molding die. The angle formed is 30 ° to 60 °, and the reinforcing material sheet is not damaged at the time of molding. Further, the stitches of the reinforcing material sheet follow the elongation of the fluororesin sheet and extend uniformly, and the entire fluororesin sheet is the reinforcing material. It is intended to be reinforced uniformly.
[0007]
[Means for Solving the Problems]
The present invention relates to a molded body for an expansion joint made of a composite sheet in which a fluororesin sheet and a fabric reinforcing material are integrated and integrated, wherein the warp or weft of the fabric reinforcing material in the composite sheet has a square shape in plan view. This is a deep-drawn molded product that is formed by press molding under heating at an angle of at least one side of the molding die of 30 ° to 60 °, and the reinforcing fabric weaves the stretch of the fluororesin sheet. A deep-drawn molded article for an expansion joint characterized in that it extends in accordance with the above (claim 1), a warp yarn of a reinforcing material in a composite sheet in which a fluororesin sheet and a reinforcing material of a woven material are integrated and integrated, or The weft yarn is arranged at an angle of 30 ° to 60 ° with respect to one side of the mold having a quadrangular shape, and the peripheral edge of the composite sheet is fixed to either the male mold or the female mold. Then, this is deep-drawn under pressure and heating, and a method for producing a deep-drawn molded body for an expansion joint (Claim 2) and the peripheral edge of the composite sheet and the edge of the male or female mold The method of manufacturing a deep-drawn molded article for an expansion joint according to claim 2, wherein the part of the composite sheet is partially loosened with respect to a part where the elongation of the composite sheet exceeds the other part. is there.
[0008]
The gist of the present invention is a molded body for an expansion joint formed by deep drawing a composite sheet in which a fluororesin sheet and a fabric reinforcing material such as glass fiber are overlapped and integrated, and the warp of the reinforcing material in the composite sheet Alternatively, the weft yarn is pressure-formed under heating at an angle of 30 ° to 60 ° with respect to at least one side of the forming die having a square planar shape, and the woven fabric of the reinforcing material is formed of the fluororesin sheet by pressure forming. A deep-drawn molded article for an expansion joint that is designed to extend following the elongation and a method for manufacturing the same.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention is a deep-drawn molded article for an expansion joint obtained by molding a laminate of a reinforcing material such as a fluororesin sheet and glass cloth using a molding die. Its uses are complex vibrations and displacements such as axial direction, twist, misalignment, etc. of various ducts such as smoke / exhaust gas systems and ventilator systems such as thermal power plants, nuclear power plants, steelworks, cement factories, chemical plants, etc. It is used for the purpose of absorbing water. The fluororesin sheet used in this invention is tetrafluoroethylene resin (PTFE). When the thickness is generally used for an expansion joint, a thickness of 0.2 to 1.0 mm is used because it is necessary to ensure gas impermeability. However, since this fluororesin sheet alone is insufficient in strength and bending resistance, a reinforcing material is integrated with it. This reinforcing material is a heat-resistant cloth material in which the warp and the weft are orthogonal to each other. For example, glass fiber, carbon fiber, aromatic polyamide fiber or the like is used. This woven fabric may be impregnated with a fluororesin dispersion in advance in order to increase the strength as a reinforcing material or to improve the adhesion to the fluororesin sheet. As the fluororesin dispersion, tetrafluoroethylene resin (PTFE), tetrafluoroethylene perfluoroalkyl vinyl ether polymer resin (PFA), or the like is used.
[0010]
The above-mentioned fluororesin sheet 1 and reinforcing material 2 such as glass fiber cloth are overlapped to form a composite sheet 3 as shown in FIG. 2, but the fluororesin PTFE sheet has a high melt viscosity and cannot be sufficiently thermally bonded. In order to firmly bond and integrate the fluororesin sheet 1 and the reinforcing material 2, for example, generally a method in which a heat-meltable fluororesin sheet 4 is sandwiched between the fluororesin sheet 1 and the reinforcing material 2 and heated under pressure is generally used. Widely practiced. Examples of the heat-fusible fluororesin include tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin (PFA) and tetrafluoroethylene-hexafluoropropylene copolymer resin (PFEP). There is also a method in which a dispersion of a heat-meltable fluororesin (not shown) is applied to the surface of the fluororesin sheet 1 and the reinforcing material 2 is superimposed on this layer and heated under pressure. At this stage, do not make a sheet that is heat-sealed, but leave it as a three-ply sheet with a hot-melt fluororesin sheet sandwiched between the fluororesin sheet and the reinforcing material. When this is deep-drawn, the fluororesin sheet and the reinforcing material may be integrated.
[0011]
The composite sheet 3 integrated as described above is disposed and fixed on the female die 12 of a deep drawing mold. In order to arrange the composite sheet 3 in the female mold 12, as shown in FIG. 3, the angle formed by the warp or weft of the reinforcing member 2 in the composite sheet 3 is at least one side of the opening surface which is the flat surface of the female mold 12 having a square shape. Is arranged in a range of 30 ° to 60 °. In FIG. 3, the warp yarn of the glass cloth of the reinforcing material is arranged at an angle of 45 ° with the longitudinal direction indicated by the arrow 50 of the female die 12. When the composite sheet 3 is set in a mold, a reinforcing material such as a glass cloth is usually disposed on the inner surface of the female mold, and a fluororesin sheet is disposed on the surface pressed by the male mold. Then, in order to make the angle between the warp yarn or the weft yarn of the glass cloth and the longitudinal direction indicated by the female arrow 50 visible, the knitting of the glass cloth is shown on the front side for convenience. When the warp yarn or the weft yarn of the reinforcing material 2 in the composite sheet 3 is arranged in such a positional relationship with one side of the female mold 12, when the compression molding is performed using this, the reinforcing material 2 is in the diagonal direction of the stitch or approximates it. It is stretched in the direction to follow the elongation of the fluororesin sheet. As a result, it is possible to obtain a product that does not cause breakage of the reinforcing material, generation of wrinkles of the fluororesin sheet, peeling of the fluororesin sheet and the reinforcing material, and the like. When the angle formed by the warp or weft of the reinforcing material with at least one side of the mold is less than 30 ° or more than 60 °, the diagonal direction of the stitch is greatly different from the length direction of the mold, and the reinforcing fiber is used for the molding in the press molding. It cannot be fully stretched along the longitudinal direction. A more preferable range of the angle formed by the warp or weft of the reinforcing material with at least one side of the mold is 40 ° to 50 °.
[0012]
Details of the procedure for setting the composite sheet 3 to the female mold 12 are shown in FIG. First, the composite sheet 3 is placed on the female mold 12. Next, fixing plates 13 and 14 are placed on the four sides of the composite sheet in order to fix the composite sheet 3 around the female mold 12. Further, in order to fix the fixing plates 13 and 14 to the female mold 12, the support points 15, 15,... At predetermined intervals of the fixing plates 13 and 14 are fixed by, for example, a scissor vise not shown. As a result, the composite sheet 3 is fixed around the female mold 12 and is subjected to pressure molding, so that it is possible to prevent creases from occurring in the obtained molded product. After setting the composite sheet in this state, the male mold 16 is lowered in the direction indicated by the arrow 60 in FIG. 3 by a conventional method, and the composite sheet 3 is pressed and deep-drawn. During compression molding, if the composite sheet 3 is partially stretched beyond the limit, a reinforcing material such as a glass cloth may be damaged. Adjust the vise and pressurize while loosening the fixed part.
[0013]
FIG. 5 shows a state where the male mold 16 is lowered to the female mold 12 and is pressure-molded. Also in FIG. 5, the scissors vise for fixing the support points 15, 15,... Of the fixing plates 13, 14 are omitted. The pressure molding is performed by heating. The mold is heated, for example, by putting the mold in a pressurized state and leaving it in an electric furnace. Further, the mold may be heated in advance before setting the composite sheet in the mold. The pressure heating molding is performed, for example, at a temperature of 250 to 450 ° C., a pressure of 0.5 to 5 kgf / cm ² , and a holding time of 10 min. 6A is a YY sectional view of FIG. 5, and FIG. 6B is a ZZ sectional view of FIG. After molding, the mold is cooled and removed, but the cooling here is also performed by a normal method, for example, by removing the mold from the electric furnace and air-cooling it with a blower, and then putting it into a water tank. In the above embodiment, the composite sheet is set in the female mold, but the composite sheet can be molded by setting it on the male mold side. After that, it is demolded to remove burrs and make a product. In FIG. 1, reference numeral 10 denotes a deep-drawn molded article according to an embodiment of the present invention.
[0014]
【Example】
(Example 1 and Comparative Example 1)
A fluororesin sheet (PTFE) having a width of 500 mm, a length of 900 mm, and a thickness of 0.3 mm was used, and a glass cloth was used as a reinforcing material. The glass cloth had a yarn thickness of 1.5 mm, and the weaving number was 32 warp yarns / 100 mm and 32 weft yarns / 100 mm. The composite sheet of fluororesin sheet and glass fiber is superposed so that the weft of the glass cloth in the composite sheet is at an angle of 45 ° with the length direction of the fluororesin sheet. (PFA) was sandwiched, and this was pressurized and heated at a temperature of 360 ° C., a pressure of 17 kgf / cm ² , and a holding time of 10 min to obtain a fluororesin sheet and a glass cloth reinforcing material integrated.
[0015]
This composite sheet was set in a female mold opening of a mold similar to that shown in FIGS. That is, the mold has a planar shape of an opening surface of 180 mm wide, 600 mm long, and 76 mm deep (see FIG. 7B). It fixed by the scissors vise at intervals of 200 mm. In this state, as shown in FIG. 3, the male mold 16 was lowered in the direction of the arrow 60, fitted into the female mold 12, and pressurized to perform heat molding. At the time of pressure molding, taking into account the tension state of the composite sheet, the composite sheet was pulled into the mold by loosening the scissors vise at a portion where the elongation of the composite sheet was more remarkable than the other portions. The heating temperature at the time of molding was 360 ° C., the pressure was 4 kgf / cm ² , and the holding time was 10 min. After molding, the mold was cooled and removed. Pressurization of the mold was performed by leaving the heated mold in an electric furnace, and cooling was performed by putting the mold into a water tank after air cooling with a blower. Thereafter, the molded body was demolded to remove burrs. As a result, a deep drawn molded body 10 having a shape as shown in FIG. 1 was obtained by integrating the fluororesin sheet and the glass fiber reinforcing material so as to obtain a beautiful deep drawn molded body free from breakage and pleats.
[0016]
A bending resistance test was performed using the same molded body as that obtained in the example as a test product. The deep-drawn molded body obtained with the mold shown in FIG. 3 was the same as that shown in FIGS. 7A and 7B. FIG. 7A shows the side surface of the deep-drawn molded body, and FIG. 7B shows the XX cross section of FIG. The bending test was performed using a bending / stretching apparatus 30 as shown in FIG. The bending / stretching test apparatus 30 includes a fixing member 24 on which a stopper 23 on one side of a test product of the deep-drawn molded body 10 is attached with a screw (not shown) on the gantry 22 and the other side of the test product of the deep-drawn molded body 10. Similarly, the sliding member 26 includes a stopper 26 attached with screws, a crankshaft 27 connected to the sliding member 26, and a driving source 28 that reciprocates the sliding member 26. The fixing member 24 is fixed to the gantry 22 in a stationary manner, but the sliding member 26 is mounted on the rail 29 so as to be reciprocated in the direction of the arrow 40. The sliding member 26 of the bending / stretching device 30 reciprocates in the direction of the arrow 40 with a crankshaft 27 connected to a driving source 28 that rotates. went. The expansion / contraction width of the sliding member 26 is 100 mm, the expansion / contraction speed is 100 times / minute, and the appearance is observed every 1,000, 3,000, 5,000, 10,000, and 50,000 times. The presence or absence of abnormality was confirmed. Further, after each expansion and contraction, a test product was cut out and subjected to a tensile test.
[0017]
Ten test pieces for the tensile test were cut out from the test pieces subjected to the five types of bending tests shown in Table 1 in a form along the warp of the glass cloth of the reinforcing material, and a total of 25 pieces were cut out as tensile test pieces. did. The size was 150 mm long × 25 mm wide. In the tensile test, an average value of 5 cut out at each expansion and contraction in accordance with JIS R 3240 was used as the tensile strength. The above bending test results are shown in Table 1, and the tensile test results are shown in Table 2.
[0018]
[Table 1]

[0019]
[Table 2]

[0020]
As is clear from Table 1, no abnormality was observed in the molded product of the present invention in any case where the number of bendings was 1,000 to 50,000.
[0021]
Also, in the tensile test, the test pieces at each stage from 1,000 times to 50,000 times of bending are 1.00 KN / 25 mm or more, and they should not cause any problems when used in an actual machine. I understood.
[0022]
(Comparative Example 1)
Using the same fluororesin sheet (PTFE) as in Example 1 and a glass cloth of a reinforcing material, the glass cloth wefts are overlapped with each other at an angle of 45 ° with the length direction of the fluororesin sheet. sandwiching the melt processible fluoropolymer sheet (PFA) of 01Mm, this temperature 360 ° C., a pressure 17 kgf / cm ^2, pressurized and heated with a retention time of 10min, integrating a reinforcing material of a fluorine resin sheet and glass cloth composite A sheet was obtained.
[0023]
This composite sheet was set in the mold shown in FIGS. 3 and 4 in the same manner as in the example. The periphery of the composite sheet was not fixed with a fixing plate at the edge of the mold. In this state, as shown in FIG. 3, the male mold 16 was lowered in the direction of the arrow, fitted into the female mold 12, and heated to perform pressure molding. Molding was performed at a heating temperature of 360 ° C., a pressure of 4 kgf / cm ² , and a holding time of 10 min. After molding, the mold was cooled and removed. The mold was heated and cooled in the same manner as in the examples. The integrally molded product of the fluororesin sheet and glass fiber thus obtained was pleated and no commercial value was recognized.
[0024]
【The invention's effect】
According to the present invention, it is a three-dimensional molded product of a fluororesin deep-drawing press integrated with a reinforcing material, and the reinforcing material is not damaged during press molding, so the fluororesin sheet and the reinforcing material are integrated. It is now possible to obtain a deep-stretched molded body with high strength. In addition, the product was smooth with no creases on the surface and excellent in commercial value. Moreover, since the integral molding of the present invention is press molding, it is excellent in terms of cost. Therefore, when this is used, for example, a thickness that ensures gas impermeability in various ducts such as smoke / exhaust gas systems and ventilator systems of thermal power plants, nuclear power plants, steelworks, cement factories, chemical plants, etc. The corner portion of the expansion joint provided with flexibility and bending resistance obtained by integrating a woven fabric reinforcing material such as a glass cloth with a fluororesin sheet can be easily produced at low cost.
[Brief description of the drawings]
FIG. 1 is a perspective view of a deep-drawn molded article of one embodiment obtained by the present invention.
FIG. 2 is an explanatory view showing the configuration of a composite sheet and its constituent members used for manufacturing the molded body of the present invention.
FIG. 3 is a perspective view of a composite sheet placed in a mold according to an embodiment used for manufacturing a molded article of the present invention.
FIG. 4 is an exploded view of a composite sheet placed in a mold according to an embodiment used for manufacturing a molded article of the present invention.
FIG. 5 is a perspective view of a male die fitted to a molding die of one embodiment used for manufacturing a molded article of the present invention.
6A is a cross-sectional view taken along a line YY in FIG. 5, and FIG. 6B is a cross-sectional view taken along a line ZZ in FIG.
FIG. 7 is a dimensional diagram showing the size of a bending test product.
FIG. 8 is a perspective view of a bending and stretching test apparatus.
FIG. 9 is a perspective view of a conventional expansion joint.
DESCRIPTION OF SYMBOLS 1 ... Fluorine resin sheet, 2 ... Reinforcement material, 3 ... Composite sheet, 4 ... Hot-melting fluororesin sheet, 10 ... Deep drawing molded object, 12 female type | molds, 13, 14 ... Fixed plate, 15 ... Supporting point, 16 ... Male type, 30 ... Bending / extracting test apparatus, 22 ... Mounting stand, 23 ... Stopping part on one side, 24 ... Fixing member, 25 ... Stopping part on the other side, 26 ... Sliding member, 27 ... Crankshaft, 28 ... Driving source, 29 ... Rail.

Claims (3)

A molded body for an expansion joint composed of a composite sheet in which a fluororesin sheet and a fabric reinforcement are overlapped and integrated, wherein the warp or weft of the fabric reinforcement in the composite sheet is a mold having a square shape in plan view. A deep-drawn molded body integrated with pressure forming under heating with an angle between at least one side of 30 ° to 60 °, and the stitches of the woven fabric of the reinforcing material follow the elongation of the fluororesin sheet by pressure heating molding. A deep-drawn molded article for an expansion joint characterized by being stretched. While arranging the warp or weft of the woven fabric of the reinforcing material in the composite sheet in which the fluororesin sheet and the reinforcing material of the woven fabric are overlapped and integrated with each other, the angle between one side of the mold having a square shape is 30 ° to 60 °. The deep drawing of an expansion joint is characterized in that the peripheral edge of the composite sheet is fixed to one of the edges of the male or female mold, and then deep drawing is performed under pressure and heating. Body manufacturing method. 3. The fixing of the peripheral edge of the composite sheet and the edge of the male or female mold is partially loosened for a portion where the elongation of the composite sheet exceeds the elongation of the other portion. A method for producing a deep-drawn molded body for an expansion joint.

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