Method of and apparatus for manufacturing glass fiber mat

Abstract: In a method of and an apparatus for manufacturing a glass fiber mat (19), bundles of glass fibers shake down onto a conveyor unit arranged horizontally (10), to form a non-oriented fiber layer (13). The non-oriented fiber layer is dried by a drier (14). Bundles of uni-directional fibers are supplied onto the dried non-oriented fiber layer, by a bundle supply device (16), to laminate the uni-directional fiber layer onto the dried non-oriented fiber layer. At the laminating, the bundles of uni-directional fibers are guided (17) in parallel relation to each other at regular intervals in a widthwise direction of the conveyor unit. The uni-directional and non-oriented fiber layers, which are laminated one upon the other, are supplied to a needler (18) and are needled thereby, to form the glass fiber mat. The glass fiber mat is carried out by a delivery roller unit (20).

Description: The invention relates to a method of and an apparatus for manufacturing glass fiber mats, in which a uni-directional fiber layer and a non-oriented or random fiber layer, which are laminated one upon the other, are needled to manufacture glass fiber mats. For manufacturing glass fiber mats in line a uni-directional fiber layer and a non-oriented or random fiber layer are laminated one upon the other and the laminated element is needled by a needler, so that the uni-directional fiber and the non-oriented fiber layer are intertwined with each other to form a united glass fiber mat. An apparatus for manufacturing such glass fiber mat is shown in Fig. 13 of the attached drawings. In this case, at an initial or start-up end section of a mat manufacturing line, bundles of uni-directional fibers 2 are first supplied onto a belt conveyor 3 from a warp beam 1 about which bundles of glass fibers such as cakes, rovings or yarns are wound, to form a uni-directional fiber layer. Bundles of continuous glass long-fibers 4 are shaked down in random onto the uni-directional fiber layer to laminate a non-oriented fiber layer 5 thereon. Subsequently, the laminated element consisting of the uni-directional fiber layer and the non-oriented fiber layer 5 is passed through a dryer 6 and is dried thereby. The laminated element is fed to a needler 7 by which the uni-directional fiber layer and the non-oriented fiber layer 5 are intertwined with each other by means of needling. By doing so, the uni-directional fiber layer and the non-oriented fiber layer 5 are united together to form a glass fiber mat. Such glass fiber mats are used to manufacture FRTP stampable sheets or plates, for example. The stampable sheet is manufactured such that the glass fiber mat is impregnated with a molten resin, by the method known from JP-B-63-15135, JP-A-61-112642 and the periodical "Plastic Age", pp 194, issued April, 1989. Further, the stampable sheet is cut or severed into a plurality of sheet elements each having a predetermined dimension or size. The stampable sheet is stamping-molded to a molded article such as a bumper beam for a vehicle or the like, which has high strength and high elasticity in one direction. The molded article that is a final product, for example, the bumper beam, must be stable in performance, for example, in flexural strength of rupture. To this end, it is necessary that the bundles of glass fibers of the uni-directional fiber layer are regularly or orderly oriented in a direction in which the strength of the molded article is required. This is similarly required in the stampable sheet that is the plate for the molded article, or in the glass fiber mat which is employed to manufacture the stampable sheet. In short, it is necessary that, when the uni-directional fiber layer and the non-directional fiber layer are intertwined with each other by needling to form the glass fiber mat, the glass fiber bundles forming the uni-directional fiber layer are oriented in parallel relation to each other at regular intervals as far as possible, in other words, without skewing or meandering, in the widthwise direction of the mat. The performance of the molded article depends upon the uniformity in orientation. For the conventional method, however, the following problems arise. That is, although the glass fiber bundles are uniformly oriented in the widthwise direction of the mat at an entrance for the conveyor, when the non-oriented fiber layer are shaked down onto the uni-directional fiber layer, is superimposed thereupon and passes through the dryer, the orientation is disturbed under the influence of hot air. Further, as the non-oriented fiber layer and the uni-directional fiber layer travel together with the conveyor and come to a location short of the needler, the orientation is further disturbed by vibration of the needler. Since in glass fiber mats needled under this condition the glass fiber bundles forming the uni-directional fiber layer are extremely irregular or non-uniform in orientation, it is not possible to produce from a stampable sheet produced by the use of such mat a molded article having a stable performance. For manufacturing stampable glass fiber mats of the before mentioned kind it is known (US-A-4 779 613) to prepare a laminate of a layer of orientated fibers and a fiber mat layer and to needle these layers in order to intertwine the fibers of the layers, wherein first a plurality of oriented fiber strands is fed onto a belt conveyor and thereafter non-orientated further fibers are superposed before needling. For manufacturing glass fiber mats it is also known (US-A-4 158 557) to produce a non-oriented or random fiber layer, to dry by a dryer and to needle this layer by a needler so that the fibers of the non-oreinted fiber layer are intertwindes with each other to form a glass fiber mat. The object of the invention is to enable to manufacture glass fiber mats composed of a dryed layer of non-oriented fibers and a layer of bundles of uni-directional fibers needled together which are stable and of even quality. This object is solved with a method having the features of claim 1 and furthermore with an apparatus having the features of claim 4. Improvements of this method and this apparatus are subject matter of the respective dependend method and apparatus claims, respectively. In accordance with the present invention glass fiber mats can be manufactured in which bundles of glass fibers are oriented in parallel relation to each other at regular intervals in widthwise direction of the glass fiber mats. Furthermore, in accordance with the present invention it can be dispensed with to rewind bundles of glass fibers around a warp beam and it is made possible to continuously manufacture a stable glass fiber mats having a dry layer of bundles of non-orientated glass fibers. The invention is further described referring to the drawings, wherein Fig. 1 is a perspective view of an apparatus for manufacturing a glass fiber mat, according to a first embodiment of the invention; Fig. 2 is a somewhat diagrammatic side elevational view showing an example of a device for applying tension to bundles of uni-directional fibers; Fig. 3 is a top plan view of an apparatus for manufacturing a glass fiber mat, according to a second embodiment of the invention; Fig. 4 is a fragmentary enlarged perspective view of the manufacturing apparatus illustrated in Fig. 3, showing the positional relationship among roving reels, shelves and hard pipes of a bundle supply device for supplying bundles of uni-directional fibers; Fig. 5 is a fragmentary side elevational view of the bundle supply device illustrated in Fig. 4; Fig. 6 is a fragmentary enlarged cross-sectional view of an entrance of the hard pipe illustrated in Fig. 4; Figs. 7a through 7e are fragmentary enlarged cross-sectional views showing various examples of a flexible pipe illustrated in Fig. 3; Fig. 8 is a fragmentary enlarged cross-sectional view of an entrance guide which is provided short of a feed roller assembly of the bundle supply device illustrated in Fig. 3; Fig. 9 is a side elevational view of an iron plate and iron pipes of the entrance guide illustrated in Fig. 8; Fig. 10a is a somewhat diagrammatic side elevational view showing the positional relationship between the entrance guide illustrated in Fig. 8 and the feed roller assembly illustrated in Fig. 3; Fig. 10b is a fragmentary enlarged diagrammatic view of one of feed rollers forming the feed roller assembly illustrated in Fig. 10a; Fig. 11 is an enlarged perspective view of the feed roller assembly illustrated in Fig. 10a; Fig. 12 is a front elevational view of the feed roller assembly illustrated in Fig. 11, showing the bundles of glass fibers which are overlapped with or superimposed upon each other in the form of lease or twill; and Fig. 13 is a perspective view of an apparatus for manufacturing conventional glass fiber mats. Referring first to Fig. 1, manufacturing apparatus comprises a pair of belt conveyors 10 and 11 which are arranged in series and substantially horizontally. The belt conveyor 10 has its initial or start-up end region, or the right-hand region in Fig. 1, at which a plurality of, four in the illustrated embodiment, supply devices 51, 52, 53 and 54 are arranged for supplying bundles of non-oriented fibers. By the supply devices 51 through 54, bundles of continuous glass long-fibers 12 are shaked down in random onto the belt conveyor 10 to form a non-oriented fiber layer or random fiber layer 13. The supply devices 51 through 54 are arranged in equidistantly spaced relation to each other along the transport direction of the belt conveyor 10, and are so arranged as to cause the bundles of continuous glass fibers 12 to fall down spirally while being reciprocated at a predetermined speed in the widthwise direction of the belt conveyor 10. In this connection, reference is made to JP-B-63-6660, for example. Each of the bundles of continuous glass fibers 12 is composed of, for example, a bundle of four-hundred (400) filaments whose single fiber or filament yarn diameter is twenty-three (23) µm. The bundles of continuous glass fibers 12 are shaked down onto the belt conveyor 10 such that the weight per unit area of the non-oriented fiber layer 13 is brought to 440 g/m², for example. The thus formed non-oriented fiber layer 13 is transported by the belt conveyor 10 and passes through a dryer 14. The dryer 14 is so arranged as to blow heated or hot air of about 50°C against the non-oriented fiber layer 13 to dry the same. Subsequently, the non-oriented fiber layer 13 is transferred to the belt conveyor 11. In a terminating end region of the belt conveyor 11, bundles of uni-directional fibers 15 are supplied onto the non-oriented fiber layer 13 from a warp beam 16. Bundles of glass fibers such as cakes, rovings or yarns, whose single filament diameter is 23 µm, whose number of bundled filaments is 2000 and whose moisture content is 4% through 5%, for example, are beforehand wound about the warp beam 16 by a width of 2.2 m, with a pitch of 4 mm, with the number of 540 and with the length of about 200 m. The warp beam 16 is rotatably supported or born by a shaft, and an electromagnetic clutch 56 is mounted to the shaft for braking the rotation of the warp beam 16. The electromagnetic clutch 56 operates in synchronism with a delivery roller assembly 20 to be described later, which moves in intermittent rotation, to apply tension to the bundles of uni-directional fibers 15. However, the warp beam 16 may be rotated by a rotational drive device 59 illustrated in Fig. 1 in double dotted lines. In this case, the warp beam 16 is rotated at its speed substantially identical with a mean taking-over speed of the delivery roller assembly moving in intermittent rotation, and serves also as means for applying tension to the bundles of uni-directional fibers. The bundles of uni-directional glass fibers 15 drawn from the warp beam 16 pass through a comb-type guide 17 and, subsequently, are supplied onto the non-oriented fiber layer 13. The comb-type guide 17 has an elongated body and a plurality of comb teeth mounted thereto, and it is preferable that the comb teeth are variable in pitch. A single bundle of uni-directional fibers 15, or two bundles of uni-directional fibers 15 may pass through a corresponding one of the comb teeth of the comb-type guide 17. The comb-type guide 17 is well known per se in the field of the textile industry, and will not be described in detail here. Subsequently, the uni-directional fiber layer and the non-oriented fiber layer 13, which are laminated one upon the other, are supplied to a needler 18 where the uni-directional fiber layer and the non-oriented fiber layer 13 are needled such that needles are pierced into them from the side of the uni-directional fiber layer. By doing so, both the layers are intertwined with each other and are united together, thereby forming a glass fiber mat 19. The needler 18 is well known per se , and will not be described in detail here. Arranged at an exit of the needler 18 is a delivery roller assembly 20 for carrying the glass fiber mat 19 out of the needler 18. The delivery roller assembly 20 is rotatively driven intermittently. In the case of the glass-fiber-mat manufacturing apparatus constructed as described above, since the warp beam 16 that is the bundle supply device for supplying the bundles of uni-directional fibers 15 is arranged between the dryer 14 and the needler 18, orientation of the bundles of uni-directional fibers 15 is not disturbed by blowing of the hot air from the dryer 14. Further, since the bundles of uni-directional fibers 15 are guided through the comb-type guide 17 and tension is applied to the bundles of uni-directional fibers 15, the latter can be guided and supplied in parallel relation to each other and in equidistantly spaced relation to each other. Thus, even if the bundles of uni-directional fibers 15 are subjected to vibration of the needler 18, the bundles of uni-directional fibers 15 can be oriented on the non-oriented fiber layer 13 straight without skewing or meandering. Application of the tension due to the electromagnetic clutch 56 is practiced as follows. That is, the electromagnetic clutch 56 becomes weak in braking force when the delivery roller assembly 20 is rotated, to apply predetermined or constant tension to the bundles of uni-directional fibers 15. When the delivery roller assembly 20 stops in rotation, the braking force of the electromagnetic clutch 56 increases, to stop or halt rotation of the warp beam 16. On the other hand, application of the tension due to the rotational drive device 59 associated with the warp beam 16 is practiced as follows. That is, since the warp beam 16 is rotatively driven at speed substantially identical with the mean taking-over speed of the delivery roller assembly 20 which moves in rotation intermittently, the bundles of uni-directional fibers 15 slacken during stop of the delivery roller assembly 20. Since, however, the bundles of uni-directional fibers 15 are tensioned or tightened when the delivery roller assembly 20 is again rotated, there is no problem in that the bundles of uni-directional fibers 15 are oriented uniformly. Fig. 2 shows another device for applying tension to the bundles of uni-directional fibers 15. The tension application device comprises a tension roller 22 which is biased by a coil spring 21 such that the tension roller 22 is lightly urged against the bundles of uni-directional fibers 15 drawn from the warp beam 16. In this case, the tension roller 22 may be supported or born rotatably by bearings, or may not be rotated. Further, the arrangement may be such that tension is applied to the bundles of uni-directional fibers 15 due only to the gravitational weight of the tension roller 22, without the use of the spring 21. Referring next to Figs. 3 through 12, there is shown an apparatus for manufacturing a glass fiber mat, according to a second embodiment of the invention. In this connection, components and parts like or similar to those illustrated in Figs. 1 and 2 are designated by the same or like reference numerals, and the description of the like or similar components and parts will be omitted or simplified to avoid repetition. In the case of the warp beam 16 serving as the bundle supply device illustrated in Figs. 1 and 2, steps are required first for preparing a plurality of bundles of glass fibers such as rovings, cakes or yarns, once for uniformizing tension applied respectively to the glass-fiber bundles, for orienting the glass-fiber bundles in parallel relation to each other, and for rewinding the glass-fiber bundles about the warp beam 16. This increases the cost, and is not economical. Further, manufacturing or production of the glass fiber mat is restricted by the length, for example, 200 m of the glass fibers wound about the warp beam 16. When the bundles of glass fibers wound about the warp beam 16 are set up or spent all, manufacturing must once stop to replace the warp beam by new one. The replacing operation must be practiced in the following manner. That is, 540 bundles of glass fibers are re-tied or refastened one by one and are passed through the comb-type guide 17. The bundles of glass fibers are adjusted also in length such that constant or predetermined tension is applied to the bundles of glass fibers. These series of operations take a few hours, and are extremely inferior in efficiency or performance. A bundle supply device 60 for supplying bundles of uni-directional fibers, in the second embodiment illustrated in Figs. 3 through 12, is arranged such that, in order to eliminate the drawbacks or disadvantages described previously, the bundles of glass fibers such as rovings, cakes or yarns are not rewound about the warp beam, but are directly supplied to the needler 18. The bundle supply device 60 comprises substantially a plurality of shelves 24 on which a plurality of reels 23 of rovings, cakes or yarns are mounted, hard straight pipes 25 for guiding the bundles of glass fibers or bundles of uni-directional fibers 15 drawn from the reels 23 of rovings, cakes or yarns, flexible pipes 26 connected respectively to the pipes 25, and a feed roller assembly 27 to which the bundles of glass fibers are supplied from the flexible pipes 26. The shelves 24, on which the reels 23 of rovings, cakes or yarns are mounted, are arranged at a location remote from the mat manufacturing line in the form of a letter V , for example. As shown in Figs. 4 and 5, each of the bundles of glass fibers 15 is drawn from a corresponding one of the reels 23 of rovings, cakes or yarns, straddles over a guide rod 28 made of stainless steel, and passes through a bore in a guide plate 29 such that two bundles are handled together. The guide plate 29 is fixedly mounted to a side face of the shelf 24 by means of screws or the like. A plurality of titania ceramics guides 30 are mounted respectively to the bores. Subsequently, as shown in Fig. 6, the bundle of glass fibers 15 is led into the straight pipe 25 which has its forward end having mounted thereto a cap 31 and a titania ceramics guide 32 and which is made of hard polyvinyl chloride (PVC). Here, if the individual bundles of glass fibers are not spaced from each other by the pipes 25, the bundles of glass fibers 15 would be brought to such a condition as to be tightly stretched at drawing, or to such a condition as to largely hang down. The bundles of glass fibers will be mingled with each other and will get entangled. Thus, the bundles of glass fibers 15 will advance while being rubbed against each other, cutting of a single yarn will occur, and fluff will be generated. At last, the bundles of glass fiber 15 will be cut or severed. The aforesaid polyvinyl chloride pipes 25 serve to space the bundles of glass fibers 15 from each other to prevent occurrence of such trouble. Furthermore, when the bundles of glass fibers 15 move vertically, the tension applied to the bundles of glass fibers 15 also varies. That is, when the bundles of glass fibers largely hang down, the tension will become large, while, when the hanging-down is small, the tension will also be small. As described previously, however, when the bundles of glass fibers 15 are taken over through the straight pipes 25, it is possible to minimize the range within which the bundles of glass fibers 15 move vertically, making it possible to reduce variation or fluctuation in tension. A material of the pipes 25 suited for these purposes may be a metal or plastic material. If, however, the pipes are made of a metal material, the pipes will become heavy, and a frame for suspending the pipes will have to become strong and durable. Further, it will be required to select pipes which have their resistant force against corrosion or erosion due to peroxide contained in a binder for the bundles of glass fibers. On the other hand, if the pipes 25 are made of a plastic material, the pipes 25 may be ones made of a hard plastic material having no tack. If the pipes 25 are made of the hard plastic material, the pipes 25 are light in weight, a frame for the pipes 25 may be one simple in construction, and there is no fear of corrosion or erosion. If each of the pipes 25 has its smooth inner wall surface, the pipes 25 may be ones made of fluorine resin, olefinic resin, polyvinyl chloride (PVC), ABS, polycarbonate (PC), acrylic resin or the like, for example. Particularly, pipes made of hard polyvinyl chloride, which is commercially available widely for piping, are suitable as the pipes 25 from the viewpoints of cost and performance. The bundles of glass fibers, which have come out of the straight pipes 25, pass through the flexible pipes 26. Each of the flexible pipes 26 has its inner wall surface which describes a gentle curve and which is wavy or corrugated in configuration. The bundles of glass fibers are led to the feed roller assembly 27. The flexible pipes 26 have their roles which reduce wear of the bundles of glass fibers 15 as far as possible to gently alter the direction of the bundles of glass fibers 15. For this reason, it is desirable that each of the flexible pipes 26 has its inner wall surface which is corrugated in configuration so that the contact area between the bundles of glass fibers 15 and the pipes 26 is small. Figs. 7a through 7e show various examples of each of the flexible pipes 26. In a flexible pipe 71 illustrated in Fig. 7a, corrugations are independent of each other in a ring-shaped configuration, and are formed in spaced relation to each other at regular intervals. In a flexible pipe 72 illustrated in Fig. 7b, corrugations are formed into a single thread or a plurality of threads. In a flexible pipe 73 illustrated in Fig. 7c, a plurality of ring-like projections are formed in an inner wall surface of the flexible pipe 73 in an independent manner. In a flexible pipe 74 illustrated in Fig. 7d, projections are formed into a single thread or a plurality of threads, In a flexible pipe 75 illustrated in Fig. 7e, a plurality of springs are inserted in and fixedly mounted to the flexible pipe 75. It is preferable that the material of the flexible pipes 26 is similar to that of the straight pipes 25. That is, it is preferable that the material of the flexible pipes 26 is one which is light in weight and whose inner wall surface is finished smoothly. For example, a trade name "Miraflex (trademark) SS, MFS-16" manufactured by Mirai Kogyo Kabushiki Kaisha and commercially available widely as cable protective tubes is preferable for the flexible pipes 26. The bundles of glass fibers 15 are supplied to the feed roller assembly 27 from the flexible pipes 26 through an entrance guide 35 as shown in Fig. 8. Since the guide 35 is located adjacent the entrance with respect to the feed roller assembly 27, the guide 35 is referred to as "entrance guide". As shown in Figs. 8 and 9, the entrance guide 35 comprises a plurality of iron pipes 36 each of which has its inner diameter equal to the outer diameter of a corresponding one of the flexible pipes 26, an iron plate 37 to which the iron pipes 36 are welded, and a plurality of titanium guides 39 each of which is mounted to an opening of the iron pipe 36 by a guide retainer 38. The iron plate 37 extends along the entire length of the feed roller assembly 27 subsequently to be described, and is rectangular in configuration which is curved arcuately. As shown in Fig. 9 which is a top plan view, the plurality of iron pipes 36 are arranged on and fixedly mounted to the iron plate 37 in staggered relation to each other in the widthwise direction of the iron plate 37 and in the longitudinal direction thereof. The flexible pipes 26 are inserted respectively into the individual iron pipes 36, and are fixedly mounted thereto. The bundles of glass fibers 15 are supplied to the feed roller assembly 27 from the flexible pipes 26 through the titania ceramics guide 39. As shown in Fig. 10a, the feed roller assembly 27 is composed of three rollers 41, 42 and 43 each of which is covered with rubber. At this time, if the iron plate 37 is planar, a center line 40 (refer to Fig. 8) of the entrance guide 35, that is, a center line of an assembly including the flexible pipes 26, the titania ceramics guide 39 and the iron pipes 36 does not coincide with or is not in agreement with the tangent line of the first roller 41 of the feed roller assembly 27. Accordingly, the bundles of glass fibers 15 will travel while being rubbed against the edge of the titania ceramics guide 39. The more the contact angle at the edge of the titanium guide 39 is large, the more fluff is generated. The generated fluff will adhere to the traveling bundles of glass fibers 15 and will move also to the the surface of the feed roller assembly 27. Fluff will be successively generated. At last, the bundles of glass fibers will be severed and will be wound about the feed roller assembly. In order to avoid or prevent such trouble, as shown in Figs. 10a and 10b, the center line or normal line 40 of the entrance guide 35 is so arranged as to be coincident with the tangent line of the first roller 41 of the feed roller assembly 27. By doing so, the contact angle between the bundles of glass fibers 15 and the edge of the titania ceramics guide 39 becomes small, so that almost no fluff is generated. The glass fibers coming out of the entrance guide 35 are supplied to the feed roller assembly 27 at intervals of the titania ceramics guides 39. Since, however, the pitch of the bundles of glass fibers 15 is extremely small or narrow such as 8 mm, there may be a case where the bundles of glass fibers will form a lease or twill at a location between the titania ceramics guides 39 and the feed roller assembly 27 as shown on the right-hand side in Fig. 11. If the bundles of glass fibers 15 are in contact with the feed roller assembly 27 while the bundles of glass fibers 15 form the lease or twill, the bundle of glass fibers 15a and the bundle of glass fibers 15b are put between the rollers, for example, between the first roller 41 and the second roller 42, while the bundle of glass fibers 15a and the bundle of glass fibers 15b are superimposed upon each other or overlapped with each other, as shown in Fig. 12. The bundle of glass fibers 15c located adjacent the bundles of glass fibers 15a and 15b becomes slow in taking-over speed, because the force put between the first roller 41 and the second roller 42 is reduced. The supply tension to the needler 18 becomes large or increases as compared with the bundles of glass fibers sent regularly or normally. Impregnation of resin into the bundle of glass fibers 15c at manufacturing of the stampable sheet will be deteriorated, thereby preventing revelation of the strength, and thereby deteriorating the outer appearance of the molded article. In view of this, a comb-type guide 44 as shown in Fig. 11 is arranged short of the first roller 41. By the guide 44, the bundles of glass fibers 15 are taken over to the feed roller assembly 27 without the fact that the adjacent bundles of glass fibers 15 do not form the lease or twill. The bundles of glass fibers 15 are supplied to the needler 17, at uniform orientation and tension, from the feed roller assembly 27 through the comb-type guide 17 which is provided at the entrance to the needler 18 and which is variable in pitch. By doing so, the bundles of glass fibers or bundles of uni-directional fibers 15 are laminated onto the non-oriented fiber layer 13 which is transported from the right to the left at a location below the feed roller assembly 27, and which is needled. In the manner described above, since the rovings, cakes or yarns are directly supplied to the glass-fiber-mat manufacturing apparatus, for example, to the needler thereof, as the bundles of uni-directional fibers, a step can be dispensed with for rewinding the rovings, cakes or yarns about the warp beam. Further, the reels for the rovings, cakes or yarns are replaced by new ones as follows. That is, initial ends of the rovings, cakes or yarns of new reels are tied or fastened, in order, to the reels in which the glass fibers approach their ends. Since it is unnecessary to adjust or regulate the length and tension as is the case of the warp beam, the replacement operation is extremely simple. Furthermore, since the replacement of the reels is practiced without stop in operation of the glass-fiber-mat manufacturing equipment, it is possible to produce the glass fiber mat continuously. As described previously, when the bundles of glass fibers 15 pass along the inner walls of the pipes 25 and 26 and through the guide, the bundles of glass fibers are rubbed and worn off. Severing or cutting of a single filament will occur frequently, and fluff will be generated. At last, the bundles of glass fiber 15 will be cut or severed. In order to prevent such cutting or severing, it is preferable that the bundles of glass fibers 15 contains water. A sizing agent is applied to the bundles of glass fibers in accordance with its object. The bundles of glass fibers 15 converge to a single strand and are wound as cakes or rovings. The glass fibers immediately after winding have a water content of 10% through 20%. In order to bring the glass fibers into bundles of glass fibers for ordinary or normal FRP or FRTP, the bundles of glass fibers 15 are dried by a drying furnace of 100°C to 120°C for ten (10) to twelve (12) hours, and are packed up and forwarded or shipped. Generally, the reason why the glass fibers for a composite material are dried is that there is a fear that resin to be composited is hydrolyzed with water, or is foamed so that the effects or advantages of the composition are marred or damaged. However, polypropylene resin is resistant to hydrolysis. Further, the manufacturing apparatus for the stampable sheet is one which acts to expel air from the glass fiber mat and, instead thereof, to push resin into the glass fiber mat. Accordingly, even if the glass fibers contains water, there is no substantial affection or influence at all. On the other hand, to a sizing agent of the glass fibers suitable for an FRTP stampable sheet whose matrix is polyolefin resin, there is added an organic peroxide, as disclosed in Japanese Patent Publication No. SHO 53-17720. When the reels such as rovings or cakes are dried under the drying condition described previously, the organic peroxide is decomposed due to heat. Thus, effects of the organic peroxide are not achieved. In view of this, normally, the bundles of glass fibers are brought to a layer-like configuration spreading thin, and hot air of 50°C is applied to the bundles of glass fibers to dry the same. That is, the bundles of glass fibers are dried for a short period of time in configuration superior in dry efficiency, at relatively low temperature, so that the organic peroxide is not decomposed. If, however, the bundles of glass fibers are wound into configuration of rovings, it takes about ten (10) days at 50°C, and it takes about one (1) month at the normal temperature and at an airy location. This is impossible to produce the bundles of glass fibers industrially. In the manner described above, presence of water content makes it possible to prevent the bundles of glass fibers 15 to be worn and to prevent fluff from being generated, without damaging the effects achieved by the composition or combination of the resin. In the second embodiment, the rovings are used whose water content is 12%. However, almost no fluff is accumulated onto the comb-type guide 17 variable in pitch, and there can be produced a uniform glass fiber mat. The water content immediately after production of the mat was about 5%. In the second embodiment described above, since the rovings, cakes or yarns are directly supplied to the glass-fiber-mat manufacturing line, for example, to the needler thereof, as bundles of uni-directional fibers, the step can be dispensed with for rewinding the rovings, cakes or yarns about the warp beam. Further, the reels for the rovings, cakes or yarns are replaced by new ones as follows. That is, initial ends of the rovings, cakes or yarns of new reels are tied or fastened, in order, to the reels in which the glass fibers approach their ends. Since it is unnecessary to adjust or regulate the length and tension as is the case of the warp beam, the replacement operation is extremely simple. Further, the arrangement may be such that spare rovings, cakes or yarns are prepared on the shelves, and their winding initial ends are tied to winding terminal ends. Furthermore, since the replacement of the reels is practiced without stop in operation of the glass-fiber-mat manufacturing line, it is possible to produce the glass fiber mat continuously. As described previously, in the second embodiment, the rovings, cakes or yarns are directly supplied to the glass-fiber-mat manufacturing line as the bundles of uni-directional fibers. Accordingly, the step is dispensed with for rewinding the rovings, cakes or yarns about the warp beam. Thus, replacement of the reels for the rovings, cakes or yarns by new ones is extremely easy and simple. Further, it is possible to continuously produce the glass fiber mat. As described above, according to the glass-fiber-mat manufacturing method and apparatus of the first and second embodiments of the invention, since the bundle supply device is arranged between the dryer and the needler, no disturbance in orientation of the bundles of uni-directional fibers due to blowing of hot air from the dryer occurs. Further, since the bundles of uni-directional fibers are guided through the comb-type guide and tension is applied to the bundles of uni-directional fibers, the bundles of uni-directional fibers are guided and supplied in parallel relation to each other at regular intervals, and are oriented onto the non-oriented fiber layer straight without skewing or meandering even if the bundles of uni-directional fibers are subjected to vibration of the needler. Accordingly, it is possible to manufacture the glass fiber mat stable in performance, by the glass-fiber-mat manufacturing method and apparatus according to the first and second embodiments of the invention.

Claims: Method of manufacturing glass fiber mats (19) composed of a non-oriented fiber layer (13) shaked down onto a conveyor means (10) and a layer of bundles of uni-directional fibers (15), which fiber layers are laminated one upon the other on the conveyor means (10, 11) and are needled to form the glass fiber mat, characterized in that, the bundles (12) of non-oriented glass fibers first are shaked down onto the conveyor means (10) to form the non-oriented fiber layer (13) which is dried thereafter, that the bundles (15) of uni-directional fibers are supplied onto the dried non-oriented fiber layer (13) to laminate a uni-directional fiber layer onto the dried non-oriented fiber layer (13), the bundles of uni-directional fibers (15) being guided in parallel to each other at regular intervals in widthwise direction of the conveyor means (10, 11), and that the thus formed laminate of uni-directional and non-oriented fiber layers is needled to form the glass fiber mat (19). Method according to claim 1, characterized in that the bundles of uni-directional fibers (15) are supplied guided spaced from each other at intervals of predetermined numbers. Method according to claim 1 or 2, characterized in that the bundles of uni-directional fibers (15) are supplied under axial tension. Apparatus for manufacturing glass fiber mats (19), said apparatus comprises conveyor means (10, 11), supply means (51 to 54) for shaking down bundles of glass fibers (12) onto said conveyor means to form a non-oriented fiber layer (13), supply means (16) for supplying bundles (15) of uni-directional fibers to form a uni-directional fiber layer, needler means (18) arranged downstream of said two supply means (16; 51 to 54) for needling said uni-directional fiber layer and said non-oriented fiber layer (13), which layers are laminated one upon the other, to intertwine said uni-directional fiber layer and said non-oriented fiber layer with each other, and delivery means (20) arranged downstream of said needler means for removing the thus manufactured glass fiber mat (19) from said conveyor means (10,11), characterized in that drying means (14) are arranged downstream of the supply means (51 to 54) for drying the non-oriented fiber layer (13), that the supply means (16) for supplying bundles (15) of uni-directional fibers are arranged downstream of said drying means (14) for supplying the bundles (15) of uni-directional fibers onto the dried non-oriented fiber layer (13), that guide means for guiding said bundles (15) of uni-directional fibers supplied from their bundle supply means (16) in parallel relation to each other at regular intervals in a widthwise direction of said conveyor means (10, 11) are provided, and that tension application means (22) for applying predetermined tension to said bundles (15) of uni-directional fibers while supplied from their bundle supply means (16) are provided. Apparatus according to claim 4, characterized in that the supply means for the bundles (15) of uni-directional fibers include a warp beam about which the bundles of uni-directional fibers are wound. Apparatus accordings to claim 4, characterized in that it includes reel means about which the bundels (15) of uni-directional fibers are wound, wherein said second bundle supply means comprises guide means for guiding the bundles of uni-directional fibers from said reel means, and feed roller means rotatively driven for supplying the bundles of uni-directional fibers onto said non-oriented fiber layer (13). Apparatus according to one of claims 4 to 6, characterized in that the tension application means (22) comprise electromagnetic clutch means (56) mounted to said warp beam (16) or to said feed roller means, said electromagneitc clutch means moves in intermittent rotation, to cause a braking action, said braking action applying tension to said bundles (15) of uni-directional fibers. Apparatus according to one of claims 4 to 7, characterized in that the tension application means (22) comprise rotational drive means for the warp beam (16) or said feed roller means, said rotational drive means being rotated at a speed substantially the same as the mean taking-over speed of said delivery means which moves in intermittent rotation, to apply the tension to said bundles (15) of uni-directional fibers. Apparatus according to one of claims 4 to 8, characterized in that the tension application means (22) comprise tension roller means which are so arranged as to be urged against said bundles (15) of uni-directional fibers. Apparatus according to one of claims 4 to 9, characterized in that the guide means include a comb-type guide (17). Apparatus according to one of claims 4 to 10, characterized in that the delivery means (20) include a delivery roller assembly. Apparatus according to one of claims 4 to 11, characterized in that it includes reel means about which said bundles (15) or uni-directional fibers are wound, wherein said second bundle supply means include shelf means on which said reel means is mounted, first guide means for guiding the bundles of uni-directional fibers drawn from said reel means, feed roller means to which said bundles of uni-directional fibers are supplied through said first guide means, and second guide means for retaining orientation of said bundles (15) of uni-directional fibers supplied from said feed roller means to said needler means. Apparatus according to claim 12, characterized in that the first guide means include pipe means and guide means. Apparatus according to claim 12 or 13, characterized in that said pipe means include a plurality of straight pipes receiving the bundles (15) of uni-directional fibers from said reel menas, and a plurality of flexible pipes connected, respectively, to said straight pipes, each of said flexible pipes having an inner wall surface which is corrugated in configuration. Apparatus according to one of claims 12 to 14, characterized in that the feed roller means include at least two rollers each of which being covered with rubber, and that the second bundle supply means further include entrance guide means for said bundels (15) of uni-directional fibers, said entrance guide means being arranged short of a first one of said rollers, said entrance guide means having a center line which is directed in tangent-line direction of said first roller. Apparatus according to claim 15, characterized in that the second bundle supply means further include guide means arranged between said first roller and said entrance guide means for orienting said bundels (15) of uni-directional fibers. Apparatus according to one of laims 12 to 16, characterized in that one of rovings, cakes and yarns are wound about said reel means. Apparatus according to one of claims 12 to 17, characterized in that the second guide means includes a comb-type guide (17) having a plurality of teeth which are variable in pitch.

Inventors: HIRAI TOSHIHARU, KIMURA HIROSHI, MAEDA MAKOTO, HIRAI, TOSHIHARU, KIMURA, HIROSHI, MAEDA, MAKOTO
Applicants: UBE NITTO KASEI CO, UBE-NITTO KASEI CO. LTD.
Application year: 1990
Main classification: B29C67
IPC codes: B29C70, D04H1