JP2006111009A - Plastic molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a polypropylene plastic molded article having a granular pattern surface satisfying low writing-in sensitivity and giving a visibly mat impression on the whole, and to propose its manufacturing method. <P>SOLUTION: The present invention relates to the polypropylene plastic molded article having the surface with the granular pattern containing a granular mountain and a granular valley. It is proposed to decrease the writing-in sensitivity of the surface showing mat appearance that the valley of the granule has the mat surface and the top of the granule has a glossy surface. The manufacturing method of the plastic molded article is also provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plastic molded product according to the first stage of claim 1 and to a method for producing it according to the first stage of claim 5.

  Plastic moldings are used, for example, in the area of the passenger compartment of automobiles. In this case, it is important that the passenger compartment has a luxurious feeling. In the case of plastic moldings, the matte surface is particularly noticeable in this regard.

  When a molded product of polypropylene material is used, if the surface is matte, there is a problem that the surface has a large writing sensitivity. The writing sensitivity should be understood as meaning the so-called writing effect of the surface that a permanent mark is left on the surface even from slight contact with a hard object such as a nail or key.

  In order to solve the problem of writing sensitivity, for example, in Patent Document 1, a granular pattern is applied to the surface of a molded product. However, the grain pattern proposed here does not exhibit the desired matte surface.

German Patent Invention No. 39 31 299 C2 Specification

  The present invention is based on the object of proposing a plastic molded part of polypropylene with a grainy surface that satisfies the requirement of low writing sensitivity and gives a generally matte visual impression, and a method for its production. .

  This object is achieved according to the invention by the features of claims 1 and 6. Claims 1 and 6 propose a plastic molded product having a granular surface comprising a grain crest and a grain trough. In this case, the grain valleys have a matte surface and the grain peaks have a glossy surface. By this method, the surface of the molded product has an overall matte impression. At the same time, the area of the surface that is in direct contact with the surroundings, ie the top of the grain crest, is better protected from further gloss (writing effect) by the glossy finish of the surface, while the actual matting of the grain valleys The surface is not in direct contact with the surroundings.

  The average height of the peak of the grains is preferably about 100 μm. This height has proven to be optimal in protecting the underlying grain valleys from contact with the object (claim 2).

  In a preferred embodiment, the crest surface of the grain crest has a lower roughness than the surface of the grain trough. The rougher the surface, the more visible the surface of the valley of the grain is, and this has the effect that the overall impression of the surface appears to be frosted (Claim 3).

  In addition, a method of manufacturing a plastic molded product having a surface provided with a granular pattern by an injection molding process is also proposed. In this method, the grained grain valleys are provided with a matte surface and the grained grain peaks are provided with a glossy surface. By this method, a high-quality, matte surface is achieved without subsequent method steps for post-processing of the molded product (claim 5).

  In a preferred refinement, the application of the granular pattern is performed during injection molding by introducing the reverse granular pattern into the injection mold. By this method, plastic moldings are produced efficiently at low cost in one working step (claim 6).

  The reverse granular pattern is preferably applied to the injection mold by an etching process. This realizes a very accurate and efficient process for the injection mold giving reproducible results (claim 7).

  Further refinements and advantages of the invention can be found from the remaining dependent claims and the description.

  The invention will be described in more detail on the basis of exemplary embodiments of the drawings.

  FIG. 1 shows a cross-sectional view of a surface 1 of a plastic molded product 2 of polypropylene material.

  In this exemplary embodiment, the plastic molding 2 takes the form of an interior part 3 in the passenger compartment of a motor vehicle. This can be, for example, a seat decoration part, a part of the center console, a pillar ornament, and / or a door pocket. This is to give a distinctive luxury to the passenger compartment of the automobile by the corresponding appearance of the interior part 3. Accordingly, the interior part 3 is preferably provided with a matte surface 1. This is because glossy plastic parts tend to look relatively cheap. If a plastic molded product 2 of polypropylene material is then selected, it is very cheap to manufacture, but has a very sensitive surface. The contact of the surface 1 with a hard object 4 such as shoes, keys or nails causes the surface to undergo a permanent writing effect, i.e. a gloss change, which considerably reduces the gorgeousness.

  Tests have shown that this writing sensitivity is directly related to the roughness 1 of the surface 1. The rougher the surface 1 is, and thus the brighter its visual impression is, the more sensitive it is to mechanical loads. The mechanical load correspondingly has the effect of smoothing the rough surface 1 and creates a glossy mark that can no longer be removed. As already described above, this effect is called a writing effect.

  However, in order to be able to achieve a matte surface impression as much as possible, the surface 1 is provided with a granular pattern 6 as shown in FIG. This generally known grain pattern 6 has grain valleys 7 and grain peaks 8 arranged to be distributed over the entire surface 1 mainly according to a visual point of view.

  In this case, the top 9 of the grain crest 8 is configured to have a glossy surface 11, that is, a low roughness surface, but the grain valley has a relatively greater roughness and is therefore matt. It has a surface 10. Thus, when the solid object 4 is moved in a direction 12 across the surface 1 of the plastic molding 2, as schematically represented in FIG. Just touch 11. It leaves no trace on this surface. This is because, in any case, the already smooth, i.e. glossy surface 11, is not smoothed by contact with the hard object 4 or only slightly smoothed. On the other hand, the troughs 7 of the frosted grains remain untouched. Therefore, the granular pattern 6 decisively improves the writing sensitivity and thus the functional durability of the plastic molded product 2. At the same time, by properly distributing the grain ridges 8 on the surface 1 of the molded article 2, an overall matte impression is still obtained.

  An average value of 100 μm has been demonstrated to be suitable for the depth 14 of the grainy pattern 6 or the height 13 of the grain pile 8, which is beneficial over a wide range of depths 14. It has been proven. This range starts at about 50 μm and has no upper limit.

  In this case, the grain ridges 8 must be very close together, or the grain valleys 7 can be very narrow, so that in normal use, the surface 10 of the grain valleys 7 can be keyed or fingered. Related objects such as are never touched.

  The distribution of the grain peaks 8 on the surface 1 is established according to a visual point of view, and it is only necessary to ensure that the matted surface 10 of the grain valleys 7 is very noticeable. Needless to say, this distribution can be irregular. The shape of the grain ridges 8 can vary greatly as well. As shown in FIG. 1, a rounded, symmetrical geometry can be provided. However, it is also conceivable to have a shape dimension in which a more pronounced edge is formed, and thus a grain pile 8 that falls more steeply.

  Therefore, the molded product 2 having such a granular pattern 6 combines the advantages of outstanding luxury and great functional durability brought out by the matte surface 1.

  The plastic molding 2 is simple to implement and is manufactured by a low cost injection molding process. Therefore, in this exemplary embodiment, the granular pattern 6 is imprinted on the surface 1 of the plastic molding 2 directly when the injection molding operation is performed. In this exemplary embodiment, this is done by providing a reverse imprint of the desired granular pattern 6 on the mold used for the injection-molded product, for example composed of a metallic material. This method makes it possible to obtain a finished plastic part 2 with a suitable granular pattern 6 in one method step without further (post-processing) steps. The application of the reverse granular pattern to the injection mold is carried out, for example, by an etching process, in which an appropriate area of the mold corresponding to the grain pile 8 after the surface 1 of the plastic molding 2. In addition, the depression is made by the etching agent.

  The method and plastic part 2 are not limited to the exemplary embodiment shown.

  In particular, the quantities stated for the depth and width of the grain ridges are merely illustrative and are not limiting in any way.

It is sectional drawing which shows the surface of the plastic molded product which has a granular pattern by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface 2 Plastic molded product 3 Interior part 4 Hard object 5 Roughness 6 Granular pattern 7 Grained valley 8 Grained mountain 9 Top 10 Matte surface 11 Glossy surface 12 Crossing direction 13 Height 14 Depth

Claims (7)

A plastic molded product made of polypropylene, the surface of which is a plastic molded product having a granular pattern including a grain crest and a grain trough,
Plastic molded product characterized in that the grain valley (7) has a matte surface (10) and the top (9) of the grain crest (8) has a glossy surface (11) .   2. The plastic molded product according to claim 1, wherein the average height (13) of the grain peaks (8) is approximately 100 μm.   3. The surface (11) of the top (9) of the grain crest (8) has a lower roughness than the surface (10) of the grain trough (7). Plastic molded product as described in 1.   The plastic molded product according to any one of claims 1 to 3, wherein the plastic molded product (2) is an interior part (3) of an automobile. A method for producing a plastic molded article having a surface provided with a granular pattern by an injection molding process,
The grained valley (7) of the grain pattern (6) is provided with a matte surface (10), and the peak (9) of the grain peak (8) of the grain pattern (6) is glossy. A method characterized in that a surface (11) is provided.   6. Method according to claim 5, characterized in that the application of the granular pattern (6) is carried out during injection molding by introducing an inverse granular pattern into the injection mold.   The method according to claim 6, wherein the application of the reverse granular pattern to the injection mold is performed by an etching process.

Images