JP5810549B2 - Method for producing bi-directional reinforcing fiber fabric - Google Patents

Description

  The present invention relates to a method for producing a bidirectional reinforced fiber fabric in which warps and wefts used as a reinforcing base material for a fiber reinforced composite material are multifilament reinforced fiber flat yarns, specifically, misalignment of a woven yarn and cutting. The bi-directional reinforcement with a special sealing treatment that can suppress the breakage of time, can maintain the uniform shape of the opening of the texture, and can obtain a fiber-reinforced plastic product with excellent surface smoothness. The present invention relates to a method for producing a textile fabric.

  Conventionally, reinforced fibers such as carbon fibers have excellent specific strength and specific elastic modulus and are easy to lighten, so as a base material for reinforcing fiber reinforced plastics, such as sports and leisure products, aircraft and general industrial applications, Is widely used for reinforcement and repair materials for concrete structures such as bridges, tunnels and buildings. As a method for molding such fiber reinforced plastic, there are various methods such as hand lay-up molding, autoclave molding, and RTM molding, which are appropriately selected depending on the shape and number of molded products, required characteristics, and the like. In these molding methods, reinforced fibers are often used in the form of a woven fabric as an intermediate substrate, and the matrix resin needs to be evenly distributed between the fibers. Is done. For this reason, there is a problem that the structure of the woven fabric itself is deformed before reaching the forming, the misalignment of warp and weft is shifted, and the woven yarn is easily unraveled when the woven fabric is cut.

  In order to cope with such a problem, for example, according to Japanese Patent Application Laid-Open No. 10-317247 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2006-2295 (Patent Document 2), a bi-directional reinforcing fiber woven fabric in which warps and wefts are interlaced is used. Therefore, it has been proposed that the intersections between the warp and the weft are partially bonded with a molten resin for sealing.

  Specifically, in Patent Document 1, a yarn made of a thermoplastic polymer having a low melting point is used as a filler, and according to the specific example, in a woven fabric of a plain weave structure in which warp and weft are alternately interlaced, all the wefts are covered. The said sealing material is arranged in a line, and the same linear sealing material is arranged every other warp, and this is heated and melted to perform the sealing. In this woven fabric, the intersection of the warps and wefts is set to 60 to 90% of the number of intersections of the entire woven fabric, and the fit to a complicated curved surface is ensured.

  By the way, as the fineness of the carbon fiber increases, the productivity improves, and it becomes possible to produce an inexpensive carbon fiber. However, a normal carbon fiber woven fabric uses woven yarn made of carbon fibers converged to a substantially circular cross section. In the woven state, the cross section of the carbon fiber yarn at the crossing portion where the warp and the weft intersect is elliptical, The yarn is crimped greatly. In particular, in a carbon fiber woven fabric using thick carbon fiber yarns, this tendency is significant because thick warps and thick wefts cross each other. For this reason, in the carbon fiber fabric crimped greatly, the fiber density becomes non-uniform, and the high strength characteristic that is characteristic of the carbon fiber cannot be sufficiently exhibited. In order to avoid the crimping of the woven yarn being large in this way, when the fabric is made of thick carbon fiber and having a low basis weight, the gap formed between the carbon fiber yarns becomes large.

In order to solve these problems, Patent Document 2 discloses a bi-directional reinforcing fiber woven fabric similar to Patent Document 1, in which at least one of warp and weft is opened and flattened, and at least on the weft. A high-strength characteristic of carbon fiber is achieved by arranging heat-bonded fibers as a stop material and heat-welding them at the intersection of warp and weft yarns, making crimps smaller together with equalizing the fiber density and making the fiber density uniform Fully exhibit the characteristics. In this sealing fabric, the heat-bonding fiber has a fineness of 110 dtex or more, the adhesive strength of at least one of warped and weft yarns that has been opened and flattened is 2 N or more, and the opening ratio of the weave is 10%. As defined below, the finished plastic product retains the desired high strength properties even if the fiber density is made uniform and thicker yarns are used for the warp and weft.

Japanese Patent Laid-Open No. 10-317247 JP 2006-2295 A

  Thus, this type of bi-directional flat yarn fabric is usually composed of a flat multifilament yarn having no twist in both the warp and weft of the woven fabric, as described in Patent Document 1 above. Has a thread form. Although this point is not clearly described in the above-mentioned Patent Document 2, it is clear that there is an intention that it is appropriate to use a non-twisted weft in order to easily spread and widen the weft.

  However, as described in Patent Documents 1 and 2, if weaving is performed by linearly attaching a heat-sealing fiber as a sealing material along a flat weft made of untwisted multifilaments, weft The portion where the heat-sealing fiber is buried between the filaments that are the constituent yarns of the yarn is likely to occur, and when the crossing portion of the warp and the weft yarn is heat-sealed while sealing the subsequent heat-sealing fiber, the heat In the portion where the fused fiber is buried between the filaments, the warp and the weft are not fused by the heat-fusible fiber at the intersection of the warp and the weft.

  The present invention has been made to solve these problems, and a specific object thereof is, in particular, in a bi-directional reinforcing fiber fabric using flat reinforcing fiber yarns, for example, by cutting the fabric into small pieces and pasting them. An object of the present invention is to provide a method for producing a bi-directional reinforcing fiber woven fabric that can easily form a predetermined preform without unraveling the woven yarn even when producing a preform for a composite material having a curved surface while being combined.

  In order to achieve the above object, the basic configuration of the present invention includes a warp made of a multifilament reinforced fiber flat yarn and a multifilament reinforced fiber flat yarn in which a low melting point fiber is attached along the yarn direction on the flat surface. A low-melting fiber having a lower melting point than the multifilament fibers constituting the warp and the weft, and is obtained on a loom. The warp is substantially untwisted, the weft has an untwisted twist, and the low-melting-point fiber is linearly arranged along the yarn direction on the weft having the untwisted twist. And the weft yarn, and the low melting point fiber is heated and melted and fused to the warp yarn and the weft yarn at the intersection of the warp yarn and the weft yarn.

  According to a preferred aspect, the weft is substantially untwisted made of multifilament reinforcing fibers, the bobbin around which the weft is wound is applied to a creel, and the weft is pulled out from the bobbin in the axial direction of the bobbin. Or, the weft has an untwisted strand made of multifilament reinforcing fibers, the bobbin around which the weft is wound is applied to a creel, and the weft is pulled out from the bobbin in a direction perpendicular to the axial direction of the bobbin. Further, when the drawn weft is inserted on the loom, the low-melting fiber is continuously provided along the weft, and the woven fiber-reinforced fabric is heated to melt the low-melting fiber. Contains.

According to a more preferred aspect, the tow width of the warp is 2.0 to 5.0 mm, the tow width of the weft is 2.0 to 5.0 mm, and the total fineness of the low melting point fiber is 55 to 330 dtex. In addition, it is desirable that multifilament flat yarn made of 6000 to 15000 carbon fibers is used for the warp and weft, and the basis weight of the woven fabric is 200 to 400 g / m ² . Further, preferably the adhesive strength of the warp yarns was measured by pulling the warp and warp of the weft in woven textiles, or weft adhesion strength of the weft was measured by pulling the adhesive strong and weft warp The adhesive strength of either one of the adhesive strengths is preferably 150 g or more.

It is a fragmentary top view of the bidirectional reinforcement fiber fabric which is typical embodiment of this invention. It is a perspective view of the vicinity of a weft insertion portion showing an example when a low melting point fiber as a sealing material is attached along a weft having unwinding twist.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

  FIG. 1 is a partial plan view of a bi-directional reinforcing fiber woven fabric obtained by the present invention. Low-melting fibers 3 are linearly attached along the longitudinal direction of the weft 2, and warp 1 and weft 2 are Each piece has a plain weave structure that alternately intersects, and the intersecting portion of the warp 1 and the weft 2 is joined by a melted low melting point fiber 3. Further, the reinforcing fiber woven fabric obtained by the present invention is woven continuously by adding the low melting point fibers 3 to the weft yarns 2 in the weaving process in the same manner as the manufacturing method of the reinforcing fiber woven fabric disclosed in Patent Document 2 above. Then, heat treatment is performed with a hot roll.

  The reinforcing fiber woven fabric obtained by the present invention can secure adhesiveness that does not cause any problems in handling in the field construction as long as 50% or more of the intersections of the warp 1 and the weft 2 are sealed. Adhesiveness greatly depends on the basis weight of the reinforcing fiber fabric, the yarn type of the low melting point fiber 3, the fineness, the conditions of the heating bar, and the like. The adhesive strength of the reinforcing fiber fabric obtained in the present invention is required to be 150 g or more for at least one of the warp 1 and the weft 2.

  The method for measuring the adhesive strength is performed as follows. First, the reinforcing fiber fabric is cut into a width of 150 mm in parallel to the warp 1 or the weft 2, and the cut reinforcing fiber fabric is fixed on a flat surface (may be on a desk) with a tape. Next, a hook of a spring scale is hooked at the center of the warp 1 or weft 2 of the reinforcing fiber fabric, and the reinforcing fiber fabric is pulled in a direction perpendicular to the warp 1 or weft 2 that is parallel and hooked to the plane, The maximum value of the scale of the scale indicated by the spring scale is measured immediately before the fusion between the warp and the weft. The measurement is repeated 20 times for each of the warp 1 and the weft 2, and the average value of each is defined as the adhesive strength of the warp 1 or the weft 2 of the reinforcing fiber fabric.

  The low melting point fiber 3 may be inserted into either the warp 1 or the weft 2 as long as it is a plain weave structure as in this embodiment and 50% of the intersection of the warp 1 and the weft 1. When attaching to the warp 1 and considering actual weaving, the same number of fused fibers as the warp 1 are prepared in a creel and arranged along the warp 1 in order to arrange each warp 1 The fibers must be woven with the fibers arranged on top. Furthermore, it is necessary to weave a large number of reinforcing fibers and a large number of low-melting fibers 3 while simultaneously controlling the tension, which requires very complicated process management. On the contrary, if the method of inserting the low-melting fiber 3 onto the weft 2 as in the method of the present invention is employed, it is sufficient to control only the tension of one low-melting fiber 3, and it is relatively easy to follow the weft 2. The low melting point fiber 3 can be inserted linearly.

Here, the most important point in attaching the low melting point fiber 3 to the weft 2 made of multifilament in the present invention is the behavior of the low melting point fiber 3 attached to the weft 2 and the shape of the weft 2 due to the behavior. The focus is on the impact on change. As described above, a multifilament yarn having substantially no twist is generally used for the weft 2 to which the low melting point fiber 3 is attached. At this time, regardless of whether or not the weft 2 is flattened, if it is untwisted, when the weft 2 is supplied onto the loom or inserted into the opening of the warp 1 (at the time of weaving) The low melting point fiber 3 sinks between the multifilaments constituting the weft 2, and a portion buried between the plurality of filaments is likely to occur. As a result, even if the low-melting fiber 3 is melted by heating the woven fabric after weaving and the intersecting portion between the warp 1 and the weft 2 is bonded, the low-melting fiber buried between the filaments as described above is not Only the filaments are fused inside the weft 2 without being exposed to the surface, and a portion where fusion with the essential warp 1 is not realized occurs. During subsequent prepreg creation and fiber reinforced molded product Not only are the above-mentioned defects likely to occur at the time of molding, but the physical properties of the final product may be greatly affected.

  In order to cope with this, it is necessary to avoid the low-melting-point fibers 3 from being simply drawn in the longitudinal direction of the weft 2 as in the prior art. Accordingly, as a result of various studies, it is preferable to positively untwist the weft yarn 2 in advance when attaching the low melting point fiber 3 to the weft yarn 2 from the viewpoint of both workability and economy. I knew it was the most effective way to get rid of the challenges. The following two methods can be used for applying this untwisting.

  The first is that the weft 2 is wound around a bobbin in a non-twisted state in which a large number of filaments are aligned in parallel, and the bobbin is hung on a creel, and then the weft 2 is pulled out in the axial direction of the bobbin. Insert the weft above. Thus, when the weft 2 is taken up from the bobbin, the weft 2 is untwisted once each time the bobbin goes around. Further, during this weaving, a bobbin around which the low melting point fiber 3 is wound is hung on a separately prepared creel for low melting point fiber, the low melting point fiber 3 is pulled out from the bobbin, and a guide is appropriately used as shown in FIG. Then, the low melting point fiber 3 is attached along the longitudinal direction of the weft 2 while the low melting point fiber 3 is aligned.

  The second method of pre-twisting the weft 2 in advance is to give a twist corresponding to the untwisting in advance when the bobbin is wound, and then apply the untwisted bobbin to the weft creel, The low melting point fiber 3 is pulled out from the bobbin in a direction perpendicular to the axis thereof, and is inserted into the opening made by the warp 1 on the loom as it is. Accordingly, even when the weft is inserted, the weft 2 is maintained in a state in which the twist corresponding to the untwisting is left. Here, as in the first method, the low-melting fiber 3 is pulled out from the bobbin hung on the low-melting fiber creel, and the low-melting fiber 3 is pulled along the longitudinal direction of the weft 2 using an appropriate guide. While being attached, the weft is inserted into the opening made of the warp together with the weft 2.

  Here, the low melting point fiber 3 is not particularly limited, such as a thermoplastic fiber such as a polyamide fiber, a polyethylene fiber, or a polyurethane fiber, but any fiber may be used as long as it is a low melting point fiber having adhesiveness. Basically, the adhesiveness differs depending on the thickness of the low melting point fiber 3 to be used, and the thicker the finer the fibers, the more clearly the adhesiveness. Will improve. However, if the low melting point fiber 3 having a finer thickness than necessary is used, the reinforcing fiber fabric becomes too rigid, which may impede resin impregnation, and may adversely affect the strength. In consideration of these, the fineness of the low melting point fiber 3 is not particularly limited, but the total fineness is preferably 55 to 330 dtex, and may be appropriately determined in consideration of use and adhesiveness.

In addition, since the low melting point fiber 3 is used as a sealing material, a roll type or a belt nip type can be generally used as a method for performing the fusion treatment of the low melting point fiber 3. It can be used. The degree of adhesion after the fusing process varies depending on the processing speed, hot roll temperature, contact angle, number of rolls, etc., and appropriate conditions can be selected as appropriate. In addition, there is no problem in the process of the fusing process even with an in-line process or an off-line process in which the process is continuously performed while weaving the fabric. In particular, the fusing temperature varies depending on the melting point of the low-melting fiber 3 to be used, and it is necessary to perform the treatment at a temperature higher than the melting point. Further, since the weaving speed is given priority in the in-line that is linked with weaving, the adhesion is controlled by the surface temperature of the hot roll, the number of rolls, the contact length of the roll, and the like. Conversely, in the off-line method, the processing speed can be adjusted with an emphasis on adhesiveness.

Next, the present invention will be described more specifically based on test examples in which the tow widths of the warp 1 and the weft 2, the fineness of the low melting point fiber 3, the sealing temperature, and the weaving conditions are changed.
In Test Examples 1 to 5 shown below, weaving with a basis weight of 300 g / m ² using carbon fiber (Pyrofil TR50S manufactured by Mitsubishi Rayon Co., Ltd., 12,000 filaments, fineness 8000 dtex) for warp 1 and weft 2 respectively. After the low melting point fiber 3 was attached along the weft 2, heat treatment was performed to fuse the warp 1 and the weft 2 at the intersection to obtain a reinforced fiber fabric, and the adhesive strength was measured. The results are shown in Table 1.

[Test Example 1]
In Test Example 1, nylon fiber manufactured by Toray Industries, Inc. having a melting point of about 110 ° C. and a fineness of 56 dtex was used as the low melting point fiber, and this was added along the weft direction of the untwisted weft. A plain woven fabric was woven using the weft. Subsequently, a heat treatment was performed by contacting with a heated roll heated to 130 ° C., and the adhesive strength of the reinforcing fiber fabric was measured. As a result, the adhesive strength was 189 g.

[Test Example 2]
In Test Example 2, a reinforced fiber fabric was obtained in the same manner as in Test Example 1 except that nylon fibers manufactured by Toray Industries, Inc. having a melting point of about 110 ° C. and a fineness of 78 dtex were used as the low melting point fibers. When the adhesive strength of the obtained reinforcing fiber fabric was measured, it had an adhesive strength of 225 g.

[Test Example 3]
In Test Example 3, a reinforced fiber fabric was obtained in the same manner as in Test Example 1 except that nylon fiber manufactured by Toray Industries, Inc. having a melting point of about 110 ° C. and a fineness of 110 dtex was used as the low melting point fiber. When the adhesive strength of the obtained reinforcing fiber fabric was measured, it had a high value of 267 g of adhesive strength.

[Test Example 4]
In Test Example 4, a reinforced fiber fabric was obtained in the same manner as in Test Example 1 except that nylon fibers manufactured by Toray Industries, Inc. having a melting point of about 110 ° C. and a fineness of 330 dtex were used as the low melting point fibers. When the adhesive strength of the obtained reinforcing fiber fabric was measured, it had a numerical value higher than that of Test Examples 1 to 3 with an adhesive strength of 522 g. The stiffness of the fiber fabric was increased and the flexibility was somewhat lacking.

[Test Example 5]
In Test Example 5, a reinforced fiber fabric was obtained in the same manner as in Test Example 1 except that nylon fibers manufactured by Toray Industries, Inc. having a melting point of about 110 ° C. and a fineness of 33 dtex were used as the low melting point fibers. When the adhesive strength of the obtained reinforcing fiber fabric was measured, the adhesive strength was 125 g, and as a reinforcing fiber fabric for earthwork use, it was easily frayed and its handleability was poor and could not be put to practical use.
Further, in Test Examples 6 to 10 shown below, carbon fibers (Pyrofil TR50S manufactured by Mitsubishi Rayon Co., Ltd., 6000 filaments, fineness 4000 dtex) are used for weft and weft, respectively, and weaving is performed with a basis weight of 200 g / m ^2. After adding low-melting fibers along the wefts, heat treatment was performed to fuse the warps and wefts at the intersections to obtain a reinforced fiber fabric, and the adhesive strength was measured. The results are shown in Table 2.

[Test Example 6]
In Test Example 6, a nylon fiber manufactured by Toray Industries, Inc. having a melting point of about 110 ° C. and a fineness of 56 dtex was used as the low melting point fiber, and this was added along the yarn direction of the untwisted weft. A plain woven fabric was woven using the weft. Subsequently, heat treatment was performed by contacting the heated roll heated to 130 ° C., and the adhesive strength of the reinforcing fiber fabric was measured. As a result, the adhesive strength was 160 g.

[Test Example 7]
In Test Example 7, a reinforced fiber fabric was obtained in the same manner as in Test Example 1 except that nylon fibers manufactured by Toray Industries, Inc. having a melting point of about 110 ° C. and a fineness of 78 dtex were used as the low melting point fibers. When the adhesive strength of the obtained reinforcing fiber fabric was measured, it had an adhesive strength of 196 g.

[Test Example 8]
In Test Example 8, a reinforced fiber fabric was obtained in the same manner as in Test Example 1 except that nylon fiber manufactured by Toray Industries, Inc. having a melting point of about 110 ° C. and a fineness of 110 dtex was used as the low melting point fiber. When the adhesive strength of the obtained reinforcing fiber fabric was measured, it had a high value of 210 g of adhesive strength.

[Test Example 9]
In Test Example 9, a reinforced fiber fabric was obtained in the same manner as in Test Example 1 except that nylon fibers manufactured by Toray Industries, Inc. having a melting point of about 110 ° C. and a fineness of 330 dtex were used as the low melting point fibers. When the adhesion strength of the obtained reinforcing fiber fabric was measured, it had a higher value than Test Examples 1 to 3 with an adhesive strength of 315 g. The stiffness of the fiber fabric was increased and the flexibility was somewhat lacking.

[Test Example 10]
In Test Example 10, a reinforced fiber fabric was obtained in the same manner as in Test Example 1 except that nylon fibers manufactured by Toray Industries, Inc. having a melting point of about 110 ° C. and a fineness of 33 dtex were used as the low melting point fibers. When the adhesive strength of the obtained reinforcing fiber fabric was measured, it was 105 g, and it was easily frayed especially as a reinforcing fiber fabric for earthwork use.

  As is clear from Tables 1 and 2, the low-melting fiber has a melting point of about 110 ° C. and a fineness of 55 dtex or more. An excellent reinforcing fiber woven fabric that does not cause trouble is obtained.

  Next, the reinforcing fiber fabric obtained in Test Example 1 and Test Example 6 was impregnated with resin using an epoxy resin for construction (E2500S) manufactured by Konishi Co., Ltd. to produce a flat plate, and measurement in accordance with JIS A1191A type As a result of carrying out the component physical property evaluation based on the law, as shown in Table 3, the strength exceeding the nominal standard (strength ≧ 2900 Mpa, elastic modulus 240 ± 24 Gpa) of the physical property value for earthwork as the bidirectional reinforced fabric was obtained. .

1 Warp 2 Weft 3 Low melting point fiber

Claims (7)

Bidirectional reinforcement obtained by weaving warps made of multifilament reinforced fiber flat yarn and weft made of multifilament reinforced fiber flat yarn with low melting point fibers along the longitudinal direction on the flat surface A method of manufacturing a textile fabric,
The low melting point fiber has a lower melting point than the multifilament fiber constituting the warp and weft,
The warp on the loom is substantially untwisted, the weft has an untwisted twist,
The low-melting fiber is linearly arranged along the yarn direction on the weft having unwinding twist,
After weaving the warp and the weft, the bi-directional reinforcing fiber is formed by heating and melting the low-melting fiber and bonding the warp and the weft through the low-melting fiber at the intersection of the warp and the weft. A method for producing a woven fabric.   The weft is substantially non-twisted of multifilament reinforcing fibers, the bobbin around which the weft is wound is applied to a creel, the weft is pulled out from the bobbin in the axial direction of the bobbin, and the drawn weft is The low-melting fiber is continuously added along the weft when weft is inserted on a loom, and the woven fiber-reinforced fabric is heated to melt the low-melting fiber. A method for producing a bi-directional reinforcing fiber fabric.   The weft has an untwisted twist made of multifilament reinforcing fiber, the bobbin around which the weft is wound is applied to a creel, and the weft is pulled out from the bobbin in a direction perpendicular to the axial direction of the bobbin. The low-melting fiber is continuously added along the weft when weft is inserted on the loom, and the low-melting fiber is melted by heating the woven fiber-reinforced fabric. Item 2. A method for producing a bi-directional reinforcing fiber fabric according to Item 1.   The method for producing a bidirectional reinforcing fiber fabric according to claim 1, comprising heating the bidirectional reinforcing fiber fabric to melt the low melting point fiber in-line or offline.   The tow width of the warp is 2.0 to 5.0 mm, the tow width of the weft is 2.0 to 5.0 mm, and the total fineness of the low-melting fiber is 56 to 330 dtex. The manufacturing method of the bidirectional reinforcement fiber fabric in any one of -4. The multifilament flat yarns consisting of 6,000 to 15,000 pieces of carbon fibers in warp and weft is used, the basis weight is 200 to 400 g / m ^2, the manufacturing method of the bidirectional reinforcing fiber fabric according to claim 5. The adhesive strength of the warp were measured by pulling the warp of the warp and the weft of woven has been the fabric, or to measure the adhesion strength of the weft by pulling the weft, adhesion of the warp yarns The method for producing a bidirectional reinforced fiber fabric according to any one of claims 1 to 4, wherein the adhesive strength of any one of the strength and the adhesive strength of the weft is 150 g or more.

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