DE2363009A1 - SQUEEGEE FOR AN IMPRAEGNATING DEVICE FOR THE PRODUCTION OF CONTINUOUS FIBERS CONTAINING FILM OR LAMINATED BODY SHAPED PIECES - Google Patents

Description

Patent attorney: DrJn * hamlet from »

Dr. Dieter F-Morf _G T-6 ₉ 5-F-Div. Dr. Hans-Α. Browns

P 22 6} 009. 3

THE GENERAL TIRE AND RUBBER COMPANY One General Street, Akron, Ohio 44 ^ 09, V.St.A.

Squeegee for an impregnation device for the production, of a sheet or laminate molding containing continuous fibers

It is known, film or * laminated bodies or plates Manufacture by placing a layer of resin material, such as polymer resin, on a pair of plastic carrier sheets is applied. Then a number of glass rovings are cut into short individual strands, after which these individual strands are randomly distributed on the base layer of resin just before the top layer of resin connected to the lower layer by means of a pair of rollers. The tensile strength of the gained The shaped piece is uniform, i.e. roughly the same in all directions, since the reinforcing glass fibers are randomly distributed are.

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The manufactured film or laminated body molding is then normally compression molded with matched metal molds. However, it turned out that the fitting in a variety of applications has weak points, often at the point of connection where the layers of the molded piece come together during compression molding. For example, when making a right-angled box, such as a trough used to transport materials, the edges weak and can easily break · This appearance is due to the way the merging of the the edge-forming layers of the molding to be traced back.

Attempts have been made to make stronger parts to manufacture. The strength of the continuous Olas rovings was used. According to a suggestion the continuous fiber strands or rovings were wound onto a drum for reinforcement purposes, after which a cut has been made in the longitudinal direction, i.e. parallel to the axis of the roller or drum. The reinforcement or the reinforcement body was then removed from the drum. Although this method of manufacture allowing stronger or more rigid parts to be formed when shaping them, there is an obvious disadvantage to this method in that the molding cannot be longer than the total circumference of the drum on which the fibers have been wound. If the rovings are not very tight or tight are wound up on the drum, they also have a tendency to move sideways or to flow, which leads to gaps between the rovings and thus to weaker points on the molded part.

In an attempt to address the above problems, reinforcements were made by weaving the fiberglass

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Rovings developed. Although the woven reinforcement mats lateral movement prevent the rovings, it turns · weaving and the fabric of rovings to be very expensive is. In addition, the individual Fasersfcränge or rovings can not adequately wet the bed, that is not completely impregnated within the resin that is required, to achieve maximum tensile strength of the pas strand. As long as the individual glass fibers of each roving are not separated from each other with the aid of the resin, they tend to friction against one another, which leads to a weakening of the material and thus to a reduction in the overall strength of the roving.

The invention is based on the object of creating a doctor blade with which a continuous Production of very long fiber-reinforced molded pieces with great uniformity can also be carried out.

According to the invention, the doctor blade is characterized by a elongated blade body, the end parts of which are in a fixed position are attached, as well as a device by means of which a substantially uniform layer of resin on a moving substrate is distributable, with at least one opening in the blade body of the doctor blade, which extends its longitudinal axis after extending through the blade body so that a continuous bundle of fibers can be drawn through the opening is after it has passed a bath of resin material and the ratio of the resin material to the fibers of the continuous fiber bundle can be kept substantially uniform. ·

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The invention will then be explained using an exemplary embodiment in conjunction with the drawings.

Show it:

Fig. 1 is a perspective view of one with the inventive Impregnation device equipped with a squeegee,

Fig. 2 is a sectional view taken along line 2-2 in Fig. 1;

Fig. 5 is a sectional view from line j5-jj in Figs. 1 and 2,

Fig. 4 is a sectional view of the doctor blade from line 4-4 in Fig. 3>,

Fig. 5 is a front view of the improved doctor blade;

Fig. Β shows a further sectional view of the doctor blade from line 6-6 in Fig. 5. » and

7 is a partial perspective view of the molded sheet or laminated body obtained with the improved doctor blade.

In the drawings, in which an embodiment according to According to the invention, FIG. 7 shows the film or laminate molded web 10 as it is produced by the impregnation machine expires. The forming web 10 has several continuous bundles 12 of fiber strands or »fiber rovings, which disposed within a mass of curable resin material 14 are. The fitting or band is between a pair

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formed by carrier foils l6a and l6b, which can consist of any thin and flexible material, so made of polyethylene plastic rolls.

Fig. 1 shows a conventional impregnation machine 20 for producing a laminate or polien web, which comprises the doctor blade 22 according to the invention. With conventional The pair of carrier foils 16a is located in the method for producing foil or laminate webs and 16b in the positions shown in FIGS. Each of the foils is made with the help of a pair of blades, so using the conventional doctor blade 50 with a thin, uniform Coating of the resin material 14 coated. When using the doctor blade 22 according to the invention, the conventional one is used Squeegee 50 only used to coat the upper carrier film 16a, while the lower carrier film 16b through the Squeegee 22 is coated. The doctor blade 22 can be in a rigid position with the aid of suitable, commonly used means are held, so with the help of the holding blocks 52. Wall body 55 can be used to cover a considerable mass of To lead resin 14 behind the doctor blade.

As can be seen from FIG. 6, the doctor blade 22 is designed as an elongated body which has opposite flat surfaces 24, 2.6 and a narrow base surface 27. This serves to distribute the resin 14 in the form of a thin layer. The surface 27 provided on the base is approximately 1.55 mm wide and extends the length of the doctor blade 22. The base surface 27 is shown as being flat. The surface 27 can, however, also have different shapes for special purposes. The doctor blade is also interspersed with several openings, which in

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In a preferred embodiment, a cylindrical part 28 and form a tapered part 29. The function of these openings is explained in more detail below.

As can be seen from FIGS. 1 and 2, the rovings bzvi. Fiber strands withdrawn from their storage positions and v / ground is passed through the openings of the first guide rod 34. With the help of the second guide rod 36 they are kept directed essentially horizontally. It is expedient that the rovings 12 enter the bath of resin 14 almost horizontally in order to increase the resistance Lower the minimum. After passing through the obliquely or conically tapering part 29 and the cylindrical part 28 the squeegee is drawn, the rovings are uniformly impregnated by the resin. After passing the squeegee, the impregnated rovings or fiber strands 12 'inserted between the coated carrier films 16a, 16b. The totality of carrier films, resin layers and impregnated rovings are then pressed together by the pair of rollers 38.

The resulting film strip or shaped piece, also called SMC, makes full use of the advantage greater Tensile strength of the fiber materials used for reinforcement. The fiber rovings can be made of various types Consist of fiber material. However, fiberglass rovings are preferred for most applications, since they have an extremely high tensile strength in the individual glass fibers, in the range of 35 200-52 700 kp / cm The glass fibers are also compatible with commonly used resin materials and are generally considered to be chemical to be considered inert. Of course, other fiber materials can also be used for the rovings, such as sisal and

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Hemp fibers, as aueti pasers made of asbestos, graphite, boron and. other wires of metal. Another group of ordinary. Materials suitable for door rovings are surrounded by fibers made of wool, cotton, polyester and nylon. The rovings or Paser strands are preferably made from a plurality of continuous fibers, primarily due to the safety factor owing the use of a large number of fibers. If If one of the fibers breaks, the load will be on the remaining one Fibers of the bundle distributed. The rovings or fiber bundles preferably consist of at least about 25 continuous ones Glass fibers, preferably from 50 individual fibers. It has showed that the longitudinal tensile strength of the finished molded piece or molding tape compared to conventional molding tapes can be increased by twice if instead of the randomly distributed short threads of the known type continuous Bundles of fibers are applied. If the one made from the molded piece or foil tape - u Part requiring greater tensile strength in more than one direction, it is possible to have a layer of continuous fibers containing shaped piece or foil tape within the press so to lay on another layer that several Layers assume a certain angle to each other, i.e. the continuous rovings or pas strands of the layers take different angles. It is obvious that the film or laminate molding obtained is a larger one Allowed a degree of freedom in the design of parts made from it.

The proportion or dimensioning of the fiber rovings with regard to The resin mixture can be changed within a wide range: For example, only a small one is required Number of continuous rovings to be used if there is only a small increase in longitudinal tensile strength

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wishes is. A ribbon or. Fitting with a share of 50 weight percent continuous fiber rovings and a proportion of 50 percent by weight resin mixture contributes Achieve optimal results in terms of maximum tensile strength without causing breakage or failure the appropriate impregnated and protected rovings occurs. Almost optimal results can be achieved if both the proportion of the fiber strands and the resin mixture are within a range of Holds 40-60 percent by weight.

The importance of the improved doctor blade is evident when one considers the need for proper impregnation of the Rovings understands. As can be seen from FIG. 4, the individual rovings 12 pass through the bath of resin 14 and become then pulled through the doctor blade. A small proportion of the resin material is in the inclined Part 29 withdrawn. This excess resin is wiped off by the moving roving when this passes through the cylindrical part 28. The most important The feature of impregnation is by means of a device to press the resin between the individual fibers of the fiber strand, in such a way that the resin towards each other Separation of the fibers is used. In this way, there is mutual abrasion of the individual fibers and possible breakage avoided. It has previously been difficult to find continuous fiber strands or rovings with heavily filled mixtures impregnate to get the maximum benefit from the inherent strength of a continuous roving. The doctor blade according to the invention makes it possible and expedient to simultaneously and continuously one

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any number of rovings up to 50 or more too impregnate.

In the preferred embodiment according to the invention The openings of the doctor blade are arranged in four parallel rows. Each row is horizontally offset or arranged in steps with respect to the adjacent row or rows., After the impregnated fiber strands through the doctor blades are drawn, however, they do not remain in their multilayer arrangement, but rather all combine within a layer or a layer. The individual openings within the doctor blade are drilled by touching surface 24 begins and pierces the squeegee vertically. In this way the cylindrical part 28 is drilled. Then will the conical part 29 worked out by counter-drilling or milling so that that he has an included angle of about. 50 ° forms. The cylindrical portion 28 can have a diameter of about 2.28 mm, which is slightly larger than the diameter of the roving before impregnation. At the In the present embodiment, the openings have each Row a center-to-center distance of about 22 mm, while adjacent rows in their horizon al position by about 9.5 mm from each other are separated. It is obvious that the shape and dimensions of the doctor blade are different from those provided described in the context of the invention, as long as the doctor blade and its openings of the double function i.e. used to orient the rovings and make each of the rovings uniform to be impregnated over its entire length.

The resin used to produce the film or laminated body molding can consist of the resin

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which is used to produce conventional film webs with a comparable arrangement. For example, polyester resins, phenol resins, epoxy resins, silicone resins, alkyl resins, acrylic resins and polyethylene resins can be used. However, thermosetting resins are mainly used. In applications which require higher tensile strength within continuous films of the type mentioned above, polyester resins are used. For certain applications it may be desirable to use a thermosetting resin such as polyester as the base material and a thermoplastic resin to improve the surface quality. When producing a shaped piece of film or laminated body, it is desirable to add a thickener to the resin mixture, such as a group II metal oxide, preferably magnesium oxide or calcium oxide. In the preferred embodiment (50 wt.% Resin mixture and 50 wt. # Rovings) containing Harzgernisch 110 parts of filler or filler against 100 parts of polyester resin. If the percentage by weight of the glass rovings is increased, then the addition of fillers in the resin mixture should be reduced proportionally in order not to reduce the total percentage by weight of the polyester or other resin too much.

V / hen the conventional impregnation machine for the production of film or laminated body moldings in one machine for the production of shaped pieces with continuous fiber strands is redesigned, then should the invention Squeegees normally get a deeper setting, i.e. should be closer to the carrier film than a conventional one Squeegee, as the resin mixture is also impregnated with the help of Rovings is fed to the fitting. The deeper setting of the squeegee results in a thinner layer of the

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Resin mixture applied to the lower carrier film. As a result, a film or sheet body is obtained oriristüek, whose fiber reinforcement and resin mixture die take the same proportions as with conventional ones There are fittings. The setting of the modified The squeegee can or should be approximately 0.25 mm below the setting conventional type, which are usually between 1.0-1.5 n »m.

A further development of the "SMC" or foil-plate or laminated body molding, through which the tensile strength of the material can be improved transversely to the orientation of the continuous rovings, can be achieved if one or more of the continuous fiber strands is introduced into a chopping or chopping station is or are located downstream of the doctor blade according to the invention. The chopping of the roving or rovings can be done in the same way as is known for conventional, comparable shaped pieces of film or laminated body. The short, usually about 25-50 mm long fiber sections are dropped with random distribution onto the combination of the base layer of resin with the impregnated continuous rovings, ie just before the top layer of resin is connected to this arrangement and in the form of a sheet or plate is pressed together. For best results, after a lot of attention for the above-described preferred embodiment, a ratio of 50 wt.% Is used by rovings, the proportion should be the shorter fiber strands over the continuous fiber strands do not exceed about 50%.

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Claims (12)

P 23 65 009. 5 yes 5 February 1974 The General Tire & Rubber Co. / ** GT-695-F-Div. 236300S godfather nta η sayings 1. Squeegee for fine impregnation device for manufacture a molding containing continuous fibers, characterized by an elongated blade body (22), whose end parts are fastened in a fixed position, as well as a device (27) by means of which a substantially uniform layer of resin on a moving one The substrate can be distributed so that at least one opening (28, 29) is provided in the blade body of the doctor blade which extends along its longitudinal axis through the blade body so that a continuous bundle of fibers can be drawn through the opening after it has passed a bath of resin material and the ratio of the Resin material are kept substantially uniform with respect to the fibers of the continuous fiber bundle can. 2. Squeegee according to claim 1, characterized in that the blade body (22) has a pair of oppositely located, has substantially parallel surfaces (24, 26) which in the end parts of the doctor blade ends and in the are directed essentially perpendicular to the path of movement of the fiber bundles. 3. Doctor blade according to claim 1, characterized in that the opening (28, 29) at least over part of its dimensions has a circular cross-section along the longitudinal axis. - 12 - 409824/0901 4. Doctor blade according to claim 1, characterized in that the longitudinal axis substantially perpendicular to the parallel ones Faces. 5. Squeegee according to claim 4, characterized in that the Opening comprises a first and a second part, that the second part (28) is substantially cylindrical is that the first part (29) has a larger diameter than the second part, and that the opening parts are arranged so that the fiber bundle enters the first part (29) and then through the second part runs. 6. Squeegee according to claim 5 *, characterized in that the second part (28) has a diameter between approximately 1.27 mm and approximately 3.8l mm, and that the second part consists of a counterbore is formed, which forms an included angle of about 50-90 °. 7. Squeegee according to claim 5 *, characterized in that the counterbore extends to a depth, polygons between about 1/4 and about 3/4 of the distance between the Corresponds to parallel surfaces (24, 26). 8. Squeegee according to claim 1, characterized in that the squeegee has several openings, which in more than are arranged in a row, and that each of the rows of openings is substantially parallel to that distributing the resin Device (27) is aligned. 9 · Squeegee according to claim 8, characterized in that the rows of openings are arranged in a staggered pattern, so that each opening is horizontal with respect to the next A09824 / 0901 236300S- GT-695-F-Div. lying pair of openings of each of the adjacent rows is offset. 10. Squeegee according to claim 8, characterized in that the longitudinal axes of adjacent openings of the same row have a distance between about 12.7 and about 25 * 4 mm. . 11. Squeegee according to claim 8, characterized in that the rows formed by the longitudinal axes of adjacent rows Levels are between 6.3-19 mm apart. 12. Squeegee according to claim 1, characterized in that the the resin distributing device from the lower edge (27) of the doctor blade body and that the lower edge is substantially parallel to the moving substrate is aligned. - 14 - 409824/0901