FI90214B - Process for making reinforced material from reinforcements and liquid materials by molding - Google Patents

Description

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A method of making a reinforced material from reinforcements and a flowable material by molding

The invention relates to a method for producing a reinforced material 5 from reinforcements and a flowable material by molding, in which a flowable material such as a liquid resin, resin components or a plastic melt is led along a feed channel and / or through a feed opening to a molding a recess extending to a part of the reinforcing material layer and the main direction of the fibers or other elongate reinforcing elements of the reinforcing material are transverse to the longitudinal direction of said recess 15 against the first depth direction.

The above method is used to make a reinforcing plastic or plastic composite consisting of a plastic body containing 20 reinforcing fibers or other reinforcing material for reinforcing the plastic. Various resins or elastomers are generally used as plastic materials. The resins are in a liquid form containing two or more components prior to final molding, or the plastic used as a raw material may be in a molten state. The reinforcing fibers, on the other hand, can consist of various elongate elements, such as fibers, and can then be in the form of fabrics, non-woven mats or fibers in one or more directions.

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A common method of manufacturing reinforced plastic articles is to use a closed mold in which a reinforcing material is first placed in the cavity, i.e. the molding space. The mold is then closed and the flowable material 35 is injected, whereby it spreads into the reinforcing structure, filling the entire molding space. This method is called the SR1M (Structural Reinforcement Injection Molding) method.

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The fluid material is generally fed from only one or a few feed channels and openings to the molding space, so that when it enters the molding space from the outflow opening of the channel to the molding space, it spreads throughout the mold cavity.

5 In order to optimize the flow of fluid, the inlet of the feed channel must be located as close as possible to the center of the shaping space, i.e. the finished object. When molding objects having a particularly large dimension in the direction of one plane, this opening 10 must then be located as close as possible to the center of said plane. Likewise, as a result, the reinforcement is often positioned so that its elongate elements are oriented parallel to this plane, i.e., the feed direction of the fluid 15 from the opening to the molding space is perpendicular to the plane of the reinforcement material. Since the fluidity of the fluid material begins to decrease as soon as it enters the molding space, either because it begins to polymerize or cools, or both, the flow time of the material into the molding space becomes a very critical factor in manufacturing. This may affect the final quality of the item. Likewise, from a manufacturing point of view, it would be desirable to shorten the flow time of the material in order to increase the capacity of the mold.

WO 89/00495 discloses a mold which aims to improve the spreading of material in the mold cavity by providing a recess in the material in the mold cavity at the feed channel. In addition, the publication mentions the possibility of arranging one-dimensional narrow passages in the material. However, this does not provide a uniform distribution to the material in the mold cavity.

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The object of the invention is to eliminate the above-mentioned drawbacks and to provide a method by which a more even flow into the molding cavity is achieved and the working time of the mold in the manufacture of a single article can be considerably shortened. To achieve this object, the method according to the invention is mainly characterized in that the reinforcing material is provided with a layer with a lower flow resistance than the other material, located transversely to the length direction 1 of the recess, into which the recess extends. Due to the recess and the lower flow resistance layer, the flowable material does not immediately face the reinforcing material causing the flow resistance from the 10 openings after molding, but can spread immediately deeper into the reinforcing material and from there to its lateral direction.

The invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 shows a commonly used SRIM method to which the method 20 is applicable, Figure 2 shows a previously known method in cross-sectional view of a mold used therein, Figure 3 shows an alternative to the method of Figure 2. as a cross-sectional view of the mold used therein, and Fig. 4 shows a method according to the invention in a cross-sectional view of the mold used therein.

Figure 1 shows a normal SRIM method in which 35 parts corresponding to the parts of Figures 2-4 are denoted by the same reference numerals.

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Figure 2 shows a mold 10 with a molding space 1 in which a reinforcement 5 is placed, which may be a fabric, a mat, unidirectional fibers or some combination thereof, i.e. generally any material comprising elongate reinforcing elements 5. The material 3 in the fluid state is guided along the feed channel 2 into the mold, whereby it enters the molding space from the feed opening 2a. As a longitudinal extension of the supply channel 2, a recess 4 is made in the reinforcement material 5 extending to at least a part of the reinforcement material layer 5, which is thus located at the supply opening 2a. The reinforcing material 5 is located so that the main direction of its elongate elements is transverse to the longitudinal direction 1. 15 of said recess 4.

When the material is fed from the opening 2a, it first spreads into the recess 4 and then begins to spread laterally as indicated by the arrows. This is based on the observation that the flow resistance for the different fluids is higher perpendicular to the plane of the above-mentioned reinforcing elements than in the direction of their plane. In this case, the material entering the opening 2a does not immediately encounter a high flow resistance, which would cause a slowdown in the flow, but may spread mainly in the directions of said planes.

Thus, with the method of Figure 2, it is possible, on the one hand, to accelerate the flow of the material to be molded and, on the other hand, to extend the available flow distances from one feed channel to the material fed, i. the invention enables molds with fewer feed openings than hitherto, which simplifies the structure of the mold.

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In the case of Fig. 2, the recess 4 extends into the entire reinforcement material layer 5 as an extension of the supply channel 2 up to the opposite wall 1a of the molding space 1. In this case, the 9021 4 5 material does not encounter any transverse layer of reinforcing material as it is applied to the molding space 1. However, if it is not desired to make the entire recess 4 extending into the reinforcing material, the layer of fibrous material is covered by the wall 1a of the molding space 1 opposite to the feed opening 2a.

Figure 4 shows a method according to the invention in which the fiber reinforcement consists of layers perpendicular to the longitudinal direction 1 of the recess 4, which are of different material such that the central layer 6 is lower than the adjacent layers 15, and the recess 4 extends at least to this layer, but it can also extend to the opposite wall 1a, as in Fig. 2. There may also be several layers 6 of natural along the depth-length direction of the recess 4.

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The invention is not limited only to the embodiments described in the previous description, but may vary within the scope of the inventive idea set forth in the appended claims. Most importantly, the recess 4 at the feed opening 2a provides a faster and more even distribution of the fluid to the reinforcing material 5, and the reinforcing elements of the reinforcing material 5 can then also be oriented in arbitrary directions, although orientations are generally the recess 4 is most preferably located perpendicular to the plane of the mats or other structures formed by said elements.

Claims (4)

A process for producing reinforced material from reinforcements and liquid materials by molding, in which liquid material, such as liquid resin, resin components or plastic melt, is conducted along an inlet channel (2) and / or through an inlet opening (2a) into a shaping space (1) comprising reinforcement (5), wherein in the reinforcement (5) there is a recess extending (4) extending into the part of the reinforcing material layer (5) in said reinforcing material (2) and the recess (4). the main direction of the fibers of the reinforcing material (5) or other elongated reinforcing elements is transverse across the longitudinal direction 1. of said recess (4), characterized in that in the reinforcing material (5) is arranged a transverse longitudinal direction 1 of the recess (4). deeper layer (6) into which the recess (4) extends and which has a lower flow resistance than the other material. Method according to claim 1, characterized in that the recess (4) extends into most of the reinforcing material layer (5) located at the feed channel (2). Method according to claim 2, characterized in that the recess (4) extends into the entire reinforcing material layer (5) all the way to the opposite wall (1a) of the shaping space (1). Method according to any of the above claims, characterized in that the reinforcing material (5) is made of fabric, mat, unidirectional fibers or a combination thereof.