WO2010036117A1

WO2010036117A1 - Plastic injection molded product with anti-slip layer, method for manufacturing a plastic injection molded product with anti-slip layer

Info

Publication number: WO2010036117A1
Application number: PCT/NL2009/050582
Authority: WO
Inventors: Martijn Schaaper; Bauke Bokma De Boer
Original assignee: Ergotray
Priority date: 2008-09-26
Filing date: 2009-09-28
Publication date: 2010-04-01
Also published as: NL2002034C

Abstract

A plastic injection molded product (l) provided with an anti-slip layer (2), wherein the anti-slip layer comprises a plastic carrier (3) provided with a relief- shaped layer (4) and wherein the anti-slip layer is thermally bonded by the side facing away from the relief-shaped layer to the plastic injection molded product. The anti-slip layer may be bonded to the plastic injection molded product by means of in-mold injection molding.

Description

Title: Plastic injection molded product with anti-slip layer, method for manufacturing a plastic injection molded product with anti-slip laver

The invention relates to a plastic injection molded product provided with an anti-slip layer.

Such products are known. For instance, the housing of a mobile telephone, the dashboard of a car, the underside of a plastic cup, a serving tray or a table in an airplane or a train may be injection molded products which may be provided with an anti-slip layer. Many implements may be provided with an anti-slip layer whereby the ease of use can be increased.

Publication US 2005/0053737 describes a container provided with a lenticular layer bonded to the outside of the container through in-mold injection molding. An outer layer is provided with optical ridges for the lenticular effect.

Publication JP 05 293 849 describes a polyethylene layer for a polypropylene cup. The polyethylene layer has a print between two transparent layers and an irregular surface structure on the outside. Publication WO 97/26814 describes a serving tray which is provided with a rubber anti-slip layer on the top side and on the underside.

Publication EP 0 637 494 describes a method for manufacturing, for instance by means of injection molding, plastic objects with a film of an anti-slip elastomer, for instance ether-based polyurethane. A drawback of the known anti-slip layer is that it may be difficult and expensive to provide a plastic injection molded product with the anti- slip layer. Also, the anti-slip function often does not work properly, in particular when the anti-slip layer becomes wet.

It is an object of the invention to provide a plastic injection molded product with an anti-slip layer which obviates the above-mentioned drawbacks. To this end. the invention provides a plastic injection molded product provided with an anti-slip layer, wherein the anti-slip layer comprises a plastic carrier provided with a relief-shaped layer and wherein the anti-slip layer is thermally bonded by the side facing away from the 7) lelief-hhaped layer to ihe plastic injeciion molded product.

By providing an anti-slip layer comprising a plastic carrier with a relief-shaped layer, the anti-slip functionality can be preserved better. Due to the presence of the plastic carrier, form friction can occur when an object is present on the injection molded product, so that movement of the object0 with respect to the injection molded product can be pi-evented and an anti- slip effect can occur. For instance, the relief-shaped layer comprises a relief with peaks and valleys. If the anti-slip layer becomes wet, the moisture can be collected or discharged in the valleys of the relief-shaped layer. In this manner, a moist layer between the anti-slip layer and an object placed on5 the anti-slip layer can be prevented, so that aquaplaning of the object with respect to the anti-slip layer can be prevented. In this manner, movement of the object on the injection molded product can be prevented when the injection molded product is wet or moist, so that an anti-slip effect can occur. For instance, the relief-shaped layer may be provided with a relief0 formed by elongated or spherical projections, or by ridges. The relief may be arranged in a random structure or in a recurrent pattern. By adapting the shape and/or the structure of the relief, the relief-shaped layer can be adapted to the use and/or to the wishes of the manufacturer anαVor user. For instance, for the anti-slip layer of a housing of a mobile telephone, a 5 different shape and structure of the relief may be used than for the anti-slip layer of a serving tray. Further, the friction of the relief-shaped layer generated in proportion to the friction coefficient can contribute to the prevention of movement of an object with respect the injection molded product and thus contribute to the anti-slip functionality. By thermally bonding the anti-slip layer to the plastic injection molded product, a good and reliable bonding of the anti-slip layer to the injection molded product can be realized.

By bonding the anti-slip layer to the plastic injection molded δ product by means of in-mold injection molding, ihe product with an anti-slip layer can be manufactured in one processing step. In this manner, the product can be manufactured in a relatively inexpensive manner. Particularly with large numbers of plastic injection molded products, a considerable cost saving can thus be realized.

10 Because the hardness of the relief-shaped layer is greater than the hardness of the plastic carrier, a relatively optimal anti-slip functionality can be achieved. Preferably, the hardness of the relief-shaped layer is approximately 50-100 shore and the hardness of the plastic carrier is approximately 1-50 shore. lδ Due to the relatively soft plastic carrier, sufficient form friction can be created when an object is placed on the anti-slip layer. The relatively soft plastic carrier can be partially impressed by the object placed on the anti- slip layer, so that the form friction can be created and an anti-slip effect occurs. Due to the form friction, a higher friction can be created compared to

20 when no form friction were present but when the friction were only the result of the forces generated in proportion to the friction coefficient of the material. Further, the anti-slip functionality can be preserved when the anti-slip layer becomes wet.

Due to the relatively hard relief-shaped layer, the anti-slip

2δ functionality can likewise be preserved, for instance when the anti-slip layer becomes wet. Because the relatively hard relief-shaped layer is located on the side of the plastic carrier facing away from the plastic injection molded product, objects are placed on the relief-shaped layer. The relief-shaped layer can thus form a sufficiently wear-resistant layer over the relatively injection molded product provided with an anti-slip layer. The plastic carrier substantially contributes to the creation of form friction that can occur when an object is on the anti-slip layer of the injection molded product. The somewhat harder relief-shaped layer not only forms a wear-resistant layer. but may also have a higher friction coefficient than the plastic carrier, and thereby contribute to the anti-slip functionality, but can also prevent aquaplaning of an object on a wet and/or moist injection molded product due to the presence of the relief, which also contributes to the anti-slip functionality of the anti-slip layer. By designing the plastic carrier to be electrically non-conductive, the anti-slip layer with the plastic carrier may, for instance, in a relatively simple manner, be received in, for instance, a mold of an injection molding machine. The electrically non-conductive plastic carrier, with the relief- shaped layer applied thereon, can be made static, so that the position of the anti-slip layer in the mold can remain virtually unchanged during injection molding. As a result, successive plastic injection molded products with an anti-slip layer can be manufactured with a relatively constant quality.

By designing the plastic carrier of the anti-slip layer to be thermally inert, deformations, due to, for instance, stretch or shrinkage, of the plastic carrier during thermal bonding can be prevented.

By designing the plastic carrier as a plastic cloth, in a relatively simple and inexpensive manner, a relatively soft carrier can be obtained. The structure of the fibers in a plastic cloth provides the cloth with a relatively high stiffness in the plane of the cloth, while the cloth is yet relatively easy to impress in a direction transverse to the plane of the cloth and consequently can yet be relatively soft. Thus, a soft layer can be created which is not sprayed away in an injection molding machine. Possibly, the space between the fibers of the plastic cloth can wholly or partly be filled by the plastic during injection molding, so that a good bonding is created between the plastic injection molded product and the plastic cloth. By wholly or partly filling the space between the fibers during injection molding, the plastic cloth may lose some of its 'impressing capacity', but even so. the form friction realized by the plastic cloth can remain sufficient. Possibly, the thickness of the plastic cloth may be adjusted. By using a plastic cloth, which usually has a certain relief by nature, the re lief- shaped layer may be applied to the plastic cloth as a reliefless layer and, after application, or after injection molding, it can assume the relief of the plastic cloth. For instance, the layer is on a paper carrier which can be bonded to the plastic cloth through a laminating technique. On the paper carrier, the layer can still be relatively flat and reliefless and, after bonding to the plastic carrier, the layer can have conformed to the relief of the plastic cloth and form a relief-shaped layer. Due to the pressure of injection molding, the relief of the plastic cloth is transferred to the layer, so that a relief-shaped layer is formed. The reliefless layer can assume a relief-shaped surface structure of the plastic cloth due to the pressure of injection molding, for instance, the layer can wholly or partly fill up space in the relief-shaped surface structure of the plastic cloth.

Preferably, the plastic cloth is a bit elastic, for instance it has an elasticity of between 1.5% and 3%. Thus, the cloth can yield a little during lamination to prevent wrinkles or folds in the anti-slip layer. With the use of a laminating technique, such as for instance laminate coating, preferably one of the two layers can yield or stretch to compensate for differences m alignment and/or to prevent wrinkles or folds. Thus, the layer applied to a paper carrier may be relatively stiff and the plastic cloth relatively elastic. During laminating of the layer applied to the paper carrier to the plastic cloth, the plastic cloth can yield slightly.

Also, due to the limited elastic properties, the plastic cloth may be suitable for having an image by means of, for instance, printing, because the image will only be subject to limited deformation and/or stretch during injection molding. Optionally, the plastic cloth comprises a knitted fabric. A knitted fabric can have limited elastic properties, so that it can be suitable for bonding of a layer through laminating to form a relief-shaped layer as well as for having an image on the knitted fabric. Optionally, the plastic clorh comprises a cross woven fabric, so that the plastic cloth can reliably be made of thermally inert design. The plastic cloth max , for instance, be designed as a woven fabric manufactured from polyester. By providing a cross woven fabric, the plastic cloth can hardly experience any stretch. By providing the plastic carrier with an image, the plastic injection molded product can be personalized by means of the anti-slip layer, for instance by providing an advertisement, or a logo. Preferably, the relief- shaped layer is of transparent design, so that an optically fine product can be made. Thus, for instance, the image provided on the plastic carrier can remain visible.

By providing the relief-shaped layer with a channel structure, moisture which may be present on the anti-slip layer can be discharged via the channel structure in an efficient manner. In this manner, aquaplaning of an object placed on the anti-slip layer can be prevented. Preferably, the relief-shaped layer is relatively thin, for instance the thickness of the relief-shaped layer is approximately 0.05-0.2 mm. Thus, the relatively hard relief-shaped layer can obtain sufficient flexibility to be able to move along with the plastic carrier when it is impressed by an object placed on the anti-slip layer, thereby creating form friction. Preferably, the plastic carrier is relatively thick, for instance the thickness of the plastic carrier is approximately 0.4-0.8 mm in order to thus be able to create sufficient form friction of the anti-slip layer.

By designing the plastic carrier wholly or partly in polyester, the plastic carrier can be designed relatively inexpensively. Further, it may relatively simply be achieved that the plastic carrier can be thermally inert and electrically non-conductive.

By designing the relief-shaped layer wholly and/or partly in pυlyurethane and/or polyvinyl chloride, despite the small thickness of the relief-shaped layer, sufficient stiffness of the relief can be achieved, so that not the relief itself is impressed, but the relief-shaped layer merely follows the deformations of the plastic carrier when it is impressed by an object which is placed on the anti-slip layer, thereby creating form friction. Preferably, the relief-shaped layer is harder than the plastic carrier. A relief-shaped layer of polyurethane and/or polyvinyl chloride usually has a higher friction coefficient than a plastic carrier designed from polyester, so that, due to the higher friction, the relief-shaped layer contributes to the anti-slip functionality of the anti-slip layer.

The invention further relates to a method for manufacturing a plastic injection molded product with an anti-slip layer comprising a plastic carrier and a relief-shaped layer. The method comprises applying a layer arranged to form a relief-shaped layer to the plastic carrier and thermally bonding the plastic carrier by the side facing away from the layer to the plastic injection molded product . For instance, the layer may be bonded to the plastic carrier by means of a laminating technique. The layer is thereby transferred from, for instance, a paper carrier onto the plastic carrier, while, by the use of glue, sufficient bonding of the layer to the plastic carrier can be ensured. The layer may then assume the relief present in the plastic carrier, for instance during lamination and/or during injection molding. The relief-shaped layer may, for instance, be on the plastic carrier, or may be partly in the plastic carrier, or may extend partly through the plastic carrier. The relief-shaped laj'er may be partry between or in the fibers of a plastic carrier designed as a plastic cloth. Also, after injection molding, the plastic of the injection molded product may be wholly or partly between or in the fibers of a plastic carrier designed as a plastic cloth and/or be wholly or partly between or in the threads of a knitted or woven fabric as a plastic carrier. Also, the relief- shaped layer may be bonded to the plastic carrier in a different manner.

Further advantageous embodiments are described in the subclaims.

The invention will be explained in more detail with reference to an exemplary embodiment represented in a drawing, in which:

Fig. 1 shows a schematic cross section of a plastic injection molded product according to the invention; Fig. 2a shows a schematic cross section of an embodiment of the anti-slip layer before injection molding; and

Fig. 2b shows a schematic cross section of a plastic injection molded product according to the invention with the anti-slip layer of Fig. 2a after injection molding. The Figures are only a schematic representation of preferred embodiments of the invention, and are shown by way of non-limiting exemplary embodiments.

Fig. 1 shows a plastic injection molded product 1 provided with an anti-slip layer 2. The plastic injection molded product may, for instance, be the housing of a mobile telephone, or a folding table in an airplane, or an underside of a plastic cup or bottle, or a serving tray, or a keyboard.

The anti-slip layer 2 comprises a plastic carrier 3 and a relief- shaped layer 4. The anti-slip layer 2 is thermally bonded to the injection molded product by the side of the plastic carrier 3 facing away from the relief-shaped layer 4. For instance, the anti-slip layer 2 is bonded to the injection molded product 1 with the aid of in-mold injection molding. In an advantageous embodiment, both the carrier 3 and the relief-shaped layer 4 are of electrically non-conductive plastic, so that they can be made static. The plastic carrier 3 is preferably softer than the relief-shaped layer 4, so that the anti-slip layer 2 can be impressed by an object present on the plastic injection molded product. In this manner, form friction between the object and the injection molded product can be cx"eated. Also, the friction coefficient of the relief-shaped layer 4 may be relatively high, for instance due to the choice of a suitable material, such as polyurethane, so that <^"> friction between ihe object and the injection molded product can be created. This also contributes to the anti-slip functionality of the anti-slip layer 2.

The relief-shaped layer 4 has a relief structure comprising peaks 5 and valleys 6. Preferably, the relief structure forms a channel structure. Via the channel structure, any moisture which may be present between an0 object placed on the anti-slip layer and the anti-slip layer can be collected and discharged efficiently. This can prevent aquaplaning of the object on the injection molded product, which also contributes to the anti-slip functionality of the anti-slip layer 2.

For manufacturing a plastic injection molded product 1 provided5 with an anti-slip layer 2. a plastic carrier 3 is provided with a relief-shaped layer 4. The relief-shaped layer 4 may, for instance, be bonded to the plastic carrier 3 with the aid of a laminating technique. Here, the relief-shaped layer of a paper carrier may be transferred to the plastic carrier, while, with the aid of glue, the relief-shaped layer may be bonded to the plastic carrier.0 For instance, the relief-shaped layer 4 may still be relatively flat on the paper carrier and only assume a relief structure after bonding to a relief- shaped plastic carrier and/or after injection molding.

For instance, in Fig. 2a, an anti-slip layer 2 is shown before injection molding, i.e. before the anti-slip layer is bonded to a plastic product5 by means of injection molding. In Fig. 2b, the anti-slip layer 2 is shown after injection molding, with the anti-slip layer 2 bonded to the plastic product 1. In Fig. 2a, the relief-shaped layer 4 is still relatively flat or reliefless, for instance due to the relief-shaped layer being bonded to the plastic earner 3 from a paper carrier, for instance through laminating. The plastic earner 30 may be designed as a knitted fabric or a woven fabric, in the cross sections of Fig. 2a and Fig. 2b schematically shown by means of threads 3a crossing threads 3b. By designing the plastic carrier 3 as a knitted fabric or a woven fabric, the plastic carrier 3 has a relief-shaped surface structure. After bonding of the anti-slip layer 2 to the plastic product 1 by means of m-mυld injection molding, the relief-shaped layer 4 may have assumed a relief structure corresponding to the relief-shaped surface structure of the knitted or woven fabric of the plastic carrier 3. During injection molding, the relief- shaped layer 4, as it were, fills up a part of the space in the surface structure of the plastic carrier 3 designed as a knitted fabric or a woven fabric. The relief-shaped layer 4 may then be provided with peaks 5 and valleys 6.

Optionally, the plastic carrier 3 may be printed with an image and the relief-shaped layer 4 may be of transparent design, so that the image can be visible through the layer 4. For instance, a plastic earner 3 designed as a knitted or woven fabric may be printed. The anti-slip layer 2 thus formed may be made static and be provided m a mold of an injection molding machine. Thus, during injection molding of the plastic injection molded product 1, the position of the anti-slip layer 2 in the mold can remain virtually unchanged. Due to the pressure of injection molding, a layer 4 can assume the relief-shaped structure of the plastic carrier 3. After an injection molding operation, the injection molded product 1 with anti-slip layer 2 can be removed from the mold, and a next anti-slip layer 2 can be placed in the mold after which a next injection molded product 1 with anti- shp layer 2 can be formed. The invention is not limited to the exemplary embodiment shown herein. Many variants are possible and will be readily apparent to a skilled person. Such variants are understood to be within the scope of the invention as set forth in the following claims.

Claims

1. A plastic injection molded product provided with an anti-slip layer, vv herein the anti-slip layer comprises a plastic carrier provided with a relief- shaped layer and wherein the anti-slip layer is thermally bonded by the side facing away from the relief-shaped layer to the plastic injection molded

5 product.

2. A plastic injection molded product according to claim 1 , wherein the anti-slip layer is bonded to the plastic injection molded product by means of in-mold injection molding.

3. A plastic injection molded product according to claim 1 or 2,0 wherein the hardness of the relief-shaped layer is greater than the hardness of the plastic carrier.

4. A plastic injection molded product according to any one of the preceding claims, wherein the hardness of the relief-shaped layer is approximately 50-100 shore. 5 5. A plastic injection molded product according to any one of the preceding claims, wherein the hardness of the plastic carrier is approximately 1-50 shore.

6. A plastic injection molded product according to any one of the preceding claims, wherein the plastic carrier is electrically non-conductive.0 7. A plastic injection molded product according to any one of the preceding claims, wherein the plastic carrier is thermally inert.

8. A plastic injection molded product according to any one of the preceding claims, wherein the plastic carrier comprises a plastic cloth.

9. A plastic injection molded product according to claim 8, whereinδ the plastic cloth comprises a cross woven fabric.

10. A plastic injection molded product according to claim 8, wherein the plastic cloth comprises a knitted fabric.

11. A plastic injection molded product according to any one of claims 8-10, wherein the plastic cloth has a relief-shaped surface structure and the relief-shaped layer assumes the relief-shaped structure of the plastic cloth. 12. A plastic injection molded product according to any one of the preceding claims, wherein the plastic carrier is provided with an image.

13. A plastic injection molded product according to any one of the preceding claims, wherein the relief-shaped layer is transparent.

14. A plastic injection molded product according to any one of the preceding claims, wherein the relief-shaped layer is provided with a channel structure. lδ, A plastic injection molded product according to any one of the preceding claims, wherein the thickness of the relief-shaped layer is approximately 0.05-0.2 mm. 16. A plastic injection molded product according to any one of the preceding claims, wherein the thickness of the plastic carrier is approximately 0.4-0.8 mm.

17. A plastic injection molded product according to any one of the preceding claims, wherein the plastic carrier comprises polyester. 18. A plastic injection molded product according to any one of the preceding claims, wherein the relief-shaped layer comprises polyurethane and/or polyvinyl chloride.

19. A method for manufacturing a plastic injection molded product with an anti-slip layer comprising a plastic carrier and a relief-shaped layer, comprising

- applying to the plastic carrier a layer arranged to form a relief-shaped layer;

- thermally bonding the plastic carrier by the side facing away from the layer to the plastic injection molded product.

20. A method according to claim 19, wherein the plastic carrier is bonded to the plastic injection molded product by means of in-mold injection molding.

21. A method according to claim 20, wherein the layer forms a relief- shaped layer on the plastic carrier after in -mold injection molding.

22. A method according to any one of claims 19-21, wherein the layer is applied to the plastic carrier through laminating.