CH718742B1 - Elastomeric article comprising a textured surface of the velvet type and process for producing such an article. - Google Patents

Abstract

The invention relates to a manufactured article formed essentially of an elastomeric material, said article having at least one visible surface (10) comprising on at least one textured portion a plurality of strands (20) extending from a base (21) of said surface and distributed over the whole of said textured portion, each strand (20) having an average height A measured from said base to a free end of the strand such that 0.250 mm ≤ A ≤ 0.600 mm and an average width B at the base such that 0.070 mm ≤ B ≤ 0.170 mm. The invention also relates to a method of manufacturing such an article by molding an elastomeric material in a mold, one molding surface of which comprises, on at least one molding surface portion, a plurality of cavities (210) having an average height h measured from said base to a free end of the strand such that 0.250 mm ≤ h ≤ 0.600 mm and an average width I at the base such that 0.070 mm ≤ I ≤ 0.170 mm.

Description

Technical area

The present invention relates to the field of manufacturing elastomer parts or thermoplastic materials. It relates more particularly to an article made of elastomeric material comprising a textured surface of the velvet type and to a method for producing such an article.

The invention can be applied advantageously to any industrial field, for the production of articles of all kinds comprising an element of elastomeric material. It will apply in a privileged application to the production of trim parts for watchmaking, and in particular the production of bracelets, as well as to other various applications implementing molded elastomer or thermoplastic parts such as leather goods. , shoemaking, packaging, automotive interiors, decoration, consumer goods and telephony, among others.

State of the art

[0003] There are now many commercial products on the market made from elastomeric materials such as rubber. By way of example, mention may be made of tyres, kitchen items, do-it-yourself items, or even furnishings, as well as items for covering and/or protecting other products, such as watch straps or cases cell phone. These products are usually formed by injection and/or molding of one or more elastomeric materials in appropriately shaped molds heated from 150°C to 300°C depending on the materials and their thicknesses according to variable durations in order to achieve their vulcanization. . The parts obtained from molding may have a smooth and/or textured surface state depending on the shape and the internal texturing of the molds used. It is also possible by subsequent treatment, in particular by laser or mechanical ablation, to create surface states that are more or less coarse and/or more or less rough to the touch.

[0004] A commonly stated inconvenience for articles and parts made of elastomer materials lies, particularly for clothing articles, precisely in their visual rendering and their touch perceived as non-qualitative because of their roughness, even their adhesion, inherent to the material from which they are made. For example, in document US 2012/0027990 A1, an article is described having frictional properties which degrade little in the presence of water. Flexible sticks stand on a surface of this article and are made, in whole or in part, of thermoplastic or vulcanized elastomer.

The object of the present invention is to provide an article made of elastomeric material which does not suffer from the defects set out above and in particular has a silky, pleasant feel, of the velvet type, similar to that produced by similar parts made of textile material. .

Disclosure of Invention

To achieve these aims, the invention relates to a method whose characteristics are mentioned in the claims.

More particularly, and according to a first object, the invention proposes a manufactured article formed essentially of an elastomeric material, for example vulcanized, said article having at least one visible surface comprising on at least one textured portion a plurality of strands s extending from a base of said surface and distributed over the whole of said portion, each strand having an average height A measured from said base to a free end of the strand such that 0.250 mm ≤ A ≤ 0.600 mm and an average width B at the base such that 0.070 mm ≤ B ≤ 0.170 mm.

In the manufactured article according to the invention, the density of the strands on the textured portion is at least equal to 10 strands per unit area expressed in square millimeters.

[0009] According to one embodiment, the average diameter of the strands at mid-height is between 0.025 mm and 0.060 mm.

According to one embodiment, the section of each strand decreases going from the base of the strand towards the end of said strand.

According to one embodiment, the center distance between the centers of the bases of two consecutive strands in two orthogonal directions in the plane of the surface is between 0.075 mm and 0.300 mm.

According to one embodiment, the average angle at the free end of the strands, measured at the intersection between the tangents to the surfaces of the strand at said end in a longitudinal section is between 6 and 30°.

[0013] Preferably, regardless of the embodiment presented above, the article is formed from a rubber material, the plurality of strands of the pattern being formed from the same material, are integral to the surface of said material. Alternatively, the article can be formed from a thermoplastic material.

[0014] Advantageously, the article of the invention may be a strap strand, in particular a watch strap.

[0015] The invention also relates, according to a second object, to a method of manufacturing a manufactured article as previously introduced, which consists in molding an elastomeric material in a mold whose molding surface comprises on at least one portion of molding surface a plurality of cavities having an average height h measured from said base to a free end of the strand such that 0.250 mm ≤ h ≤ 0.600 mm and an average width I at the base such that 0.070 mm ≤ I ≤ 0.170 mm.

[0016] Preferably, according to this process, cavities are produced on the mold by laser ablation in the molding surface.

[0017] In addition, according to one embodiment, the mold is heated during injection to a temperature of between 160° C. and 250° C. [to be checked]

Finally, the molding of the elastomeric material may result from an injection of the elastomeric material in the liquid state into the mold or from a compression in the solid state in the mold.

Brief description of the drawings

Other features of the present invention will appear more clearly on reading the following description, made with reference to the accompanying drawings, in which:

[0020] - Figure 1 shows a side view of a textured surface portion of a manufactured article according to the invention, and

- Figure 2 shows a top view of a textured surface portion of a sample of a part according to the invention taken under an electron microscope.

Embodiment(s) of the Invention

In the following description, the invention will be presented in relation to the production of a manufactured article having a velvet-like surface texture, such as a bracelet strand consisting of an elastomer part textured with using a suitable mould. However, this application should not be taken as limiting the scope of the present invention, which will apply equally to the production of any type of article manufactured from elastomeric material.

[0023] The invention advantageously proposes the procurement of a manufactured article made of vulcanized elastomeric material comprising on one surface, or more precisely on at least one surface portion, a velvet-like texture obtained entirely in the mass of the elastomeric material, during molding of a base blank using a suitable mold cavity, said cavity having a molding surface texturing adapted to form on a surface portion of said blank in contact with this mold portion textured a plurality of strands of shapes and sizes such that the feel and the corresponding texture of said surface portion of the blank after molding and cooling is similar to that of a textile pile.

[0024] Such a velvet texture advantageously provides a very qualitative finish, appearance and feel of the textile type for articles made of elastomeric materials, the usual appearance and feel of which, more matt, synthetic and rubbery, is mostly not perceived. as qualitative by consumers for the articles which are made of it but rather as protective, mechanically resistant, and impermeable which are the properties sought as a priority for articles made of elastomer materials.

[0025] The manufactured articles according to the invention thus advantageously provide the same technical advantages of protection, mechanical resistance and resistance to liquid fluids while offering a very qualitative appearance and feel sought after more and more by consumers.

[0026] Figures 1 and 2 show a portion of velvet texture of a manufactured article according to the invention, respectively according to a side view (fig.1) detailing the conformation of the strands of material and a top view (fig. 2) detailing the arrangement of said strands with respect to each other on a textured surface portion of the manufactured article.

The strands 20 protrude from a substantially planar surface 10 of the manufactured article 1. The surface 10 may in particular be a surface of a blank of elastomeric material which has been molded or, alternatively, a sheet of calendered elastomeric material. molded in order to be textured to include the strands forming the velvet texture of the invention, this calendered sheet being able subsequently to be affixed and fixed to a blank of elastomeric material and vulcanized therewith or adhered, in particular by gluing.

Each strand 20 has a substantially triangular shape, with a base 21 made in one piece on the surface 11 of the article and which has a section which gradually decreases as it moves away from said surface 11. As shown in Figure 1 , each strand 20 is characterized by a height A, measured between its base and its free tip, a base width or diameter B measured between the ends of the base 21 joining the base 21 of an adjacent strand 20, a diameter at mid -height C and a vertex angle D.

According to the invention, the average height A of the strands 20 is between 0.250 mm and 0.600 mm and the average width B at the base is between 0.070 mm and 0.170 mm.

In addition, the average diameter C at mid-height is between 0.025 mm and 0.060 mm and the average angle D at the free end of the strands, measured at the intersection between the straight lines tangent to the surfaces of the strand 20 at said end is between 6 and 30°.

[0031] In addition, as shown more particularly in FIG. 2, the spacing E between the centers of the bases 21 of two consecutive strands 20 in two orthogonal directions X, Y in the plane of the surface 10 on which said strands protrude is between 0.075 mm and 0.300 mm, the density of the strands 20 on the textured portion it being at least equal to 10 strands per mm2.

A conformation and a distribution of the strands 20 as previously defined on the surface or surface portion 10 of a manufactured article according to the invention advantageously provides a velvet-like texture comparable to fibers of the order of 1, 5 to 1.7 DTEX, providing an extremely silky touch of short and dense fibers, both flexible and resistant, without roughness or abrasion on manual contact.

The manufactured article of the invention comprises at least one skin, that is to say an outer layer made of elastomeric material, or is entirely formed of vulcanized elastomeric material, including a surface 10 or surface portion 10 free is textured in accordance with the invention.

By way of example, the elastomers used to produce the manufactured object 10 of the invention can be chosen from general elastomers, such as natural rubber, polyisoprene, a copolymer of butadiene and styrene, known as the abbreviation SBR, or again, polybutadiene. The elastomers can also be chosen from special elastomers, such as for example a copolymer of isobutylene and isoprene, known under the abbreviation of IIR, polychloroprene, a copolymer of ethylene and propylene-diene, known under the name EPDM, or a copolymer of ethylene and propylene, known as EPM.

Said manufactured object may in particular consist of one or more sheets of calendered elastomeric material as defined above. The sheets of calendered material can be assembled on top of each other by vulcanization, in a conventional way for the manufacture of elastomer parts, to form a blank as previously mentioned for the purposes of molding the manufactured article of the invention. Each sheet of calendered material constituting the blank may in particular be of a thickness preferably comprised between 0.5 mm and 10 mm, more preferably still comprised between 1 mm and 3 mm.

The manufactured object according to the invention can advantageously be obtained by implementing a molding process as described below.

A first step consists first of all in obtaining a preparation of elastomeric material chosen from the basic components mentioned above. The preparation of elastomeric material essentially consists initially of a liquid base of elastomeric material, for example natural rubber, EPDM or EPM, which is mixed so as to obtain a homogeneous mixture.

This preparation is then reserved in liquid form or alternatively in raw calendered sheets, intended for the production of vulcanized assemblies with other components of elastomeric material, which are identical or of a complementary nature in order to be able to be crosslinked together.

[0039] The elastomer preparation is then molded in a mold including a textured molding surface in order to comprise on at least one molding surface portion a plurality of cavities having an average height h and an average width I at the base conforming to the dimensions A and B of the strands 20 of the texture of the manufactured object produced as previously mentioned.

[0040] The cavities of the mold can advantageously be arranged so as to form a structure similar to a "honeycomb", which has the advantage of organizing in a regular manner on the textured surface of the mold and therefore of the molded part. the cavities, respectively the strands 20, in order to control the scheduling and the spacing of said strands 20 in particular in the molded part. In addition, this makes it possible to reduce the residual surfaces between the bases of the molded strands by allowing regular flow of the fluid elastomeric material in the mold, independently of the injection pressures or the dynamic effects of the liquid material in the mold during the molding. ''injection.

The machining of the cavities in the molding surface can be carried out by means of a laser beam for example.

The molding is carried out in such a way that the elastomeric material injected into the mold is at least partially vulcanized, at a temperature between 160° C. and 250° C.

Alternatively to an injection of liquid elastomeric material into a mould, the manufactured object of the invention can also be produced by molding a calendered sheet of elastomeric material as defined above, therefore in the solid state, compressed in the mould.

As an indication, five different samples of manufactured articles in accordance with the present invention were made by molding as previously presented. These different samples were then subjected to dimensional analysis of their structures and in particular of their strands 20, in order to verify their conformity with the desired dimensional parameters of the present invention.

The characteristic measurements of the various samples produced are reported below in Table 1.

It is interesting to note that samples 1 and 5, respectively constituting the samples whose strands are of the smallest and largest dimensions, respectively, in terms of average height A and base diameter B at all times. less, constitute extreme examples of satisfactory velvet structuring within the meaning of the present invention. Indeed, it turned out to be extremely tricky, if not impossible, to achieve a uniform structuring of strands 20 of height less than the average height A of sample 1, in particular with strands individually distinct from each other to to provide the silky touch effect, analogous to velvet, desired for the invention, without excessive roughness and friction appearing on touch.

Furthermore, heights and widths of strands greater than those of sample 5 tend to provide wider strands, the ends of which are less tapered, and of texture that is no longer silky but wired, therefore with a lower qualitative rendering. for the consumer, in particular for manufactured articles of dressing such as strands of bracelets, dials, or other parts of dressing of watches and jewels for example.

Table 1:

1 0.276 0.074 0.029 12,033 0.075 0.111 2 0.428 0.071 0.034 6.776 0.12 0.171 3 0.508 0.109 0.042 10.851 0.11 0.159 4 0.146 0.146 0.056 0.24 0.17 .22

The invention thus provides articles manufactured in elastomeric materials endowed with a velvet texture similar to a textile velvet and having a qualitative rendering and touch, particularly suitable for the production of parts of all kinds, in particular covering for watches and jewellery, and for example bracelet strands.

The invention may also be applied to the manufacture of textured parts in elastomer or thermoplastic materials for other industries and applications and in particular for shoemaking, eyewear, consumer goods and telephony, automobiles, in particular interior parts, leather goods, decoration or even packaging.

Claims (10)

1. Manufactured article formed essentially of an elastomeric material, said article having at least one visible surface (10) comprising on at least one textured portion a plurality of strands (20) extending from a base (21) of said surface and distributed over the whole of said portion, characterized in that each strand (20) has an average height A measured from said base to a free end of the strand such that 0.250 mm ≤ A ≤ 0.600 mm and an average width B at the base such that 0.070 mm ≤ B ≤ 0.170 mm, and in that the density of the strands (20) on the textured portion is at least equal to 10 strands per unit area expressed in square millimeters (mm<2>). 2. Article according to claim 1, characterized in that the average diameter (C) of the strands (20) at mid-height is between 0.025 mm and 0.060 mm. 3. Article according to any one of claims 1 and 2, characterized in that the section of each strand (20) decreases from the base of the strand towards the end of said strand. 4. Article according to one of claims 1 to 3, characterized in that the center distance (E) between the centers of the bases (21) of two consecutive strands (20) in two orthogonal directions in the plane of the surface is included between 0.075mm and 0.300mm. 5. Article according to any one of claims 1 to 4, characterized in that the mean angle (D) at the free end of the strands (20), measured at the intersection between the tangents to the surfaces of the strand (20 ) at said end in a longitudinal section is between 6 and 30°. 6. Article according to any one of claims 1 to 5, characterized in that said article is a bracelet strand. 7. A method of manufacturing a manufactured article according to one of claims 1 to 6 and formed essentially of an elastomeric material, said article having at least one visible surface (10) comprising on at least one textured portion a plurality of strands (20) extending from a base (21) of said surface and distributed over the whole of said portion, each strand (20) having an average height A measured from said base to a free end of the strand such as 0.250 mm ≤ A ≤ 0.600 mm and an average width B at the base such that 0.070 mm ≤ B ≤ 0.170 mm, the density of the strands (20) on the textured portion being at least equal to 10 strands per unit area expressed in square millimeter mm2 the method consisting in molding the elastomeric material in a mold whose molding surface comprises on at least one molding surface portion a plurality of cavities having an average height h measured from said base to a free end of the strand such that 0.250mm ≤ h ≤ 0.600 mm and an average width I at the base such that 0.070 mm ≤ I ≤ 0.170 mm. 8. Method according to claim 7, characterized in that the production of the cavities on the mold is obtained by laser ablation in the molding surface. 9. Process according to claim 7 or 8, characterized in that the mold is heated during injection to a temperature of between 160°C and 250°C. 10. Method according to one of claims 7 to 9, characterized in that the elastomeric material is injected in the liquid state into the mold or compressed in the solid state in the mold.