JP2010535268A - Process for producing coated elastomer profile, elastomer profile and use thereof - Google Patents

Abstract

  The present invention relates to a method for producing a coated elastomer profile (1) having a base substrate (3) made of an elastomeric material, wherein in the first step the coating material (11) is a base made of an elastomeric material. Application to the substrate (3), in which case the coating material (11) contains a lubricant (13) containing a polymer material. In the second step, the base substrate (3) provided with the coating material (11) is heated to a temperature above the melting temperature of the polymer material contained in the lubricant (13), with the polymer film (17 ) Is formed on the surface of the elastomer profile. Finally, the elastomer profile is irradiated to cure the polymer film (17). The invention further comprises an elastomer profile having a base substrate (3) made of an elastomeric material, comprising a coating (5) consisting of a coating material (11) containing a lubricant (13) containing at least one polymer material. About. The coating (5) has a first layer (15) made of a coating material, a second layer (17) is formed on the first layer (15), and the second layer (17 ) Contains essentially cross-linked polymeric material. The elastomer profile is used, for example, as a wiper rubber for window wipers or window squeegees.

Description

Prior Art The present invention relates to a method for producing a coated elastomer profile having a base substrate made of an elastomer material. Furthermore, the invention starts from an elastomer profile according to the superordinate concept of claim 10. Finally, the invention also relates to the use of the elastomer profile according to the invention or the elastomer profile produced by the process according to the invention.

  The elastomer profile is used for manufacturing a wiper rubber or a string-like seal material, for example. This type of wiper rubber is used, for example, in automobile window wipers. Another area of application of wiper rubber is window squeegees used, for example, for cleaning window glass at home.

  In order for window wipers to produce satisfactory results with little energy consumption, it is generally necessary to reduce the friction when the wiper rubber used as a window wiper is activated. For this purpose, it is known to provide wiper rubber with, for example, a graphite coating or an anti-friction lacquer coating.

  Coatings used to reduce friction often contain a thermosetting two-component system consisting of a binder and a curing agent. Such thermosetting systems contain, for example, hydroxyl-functionalized polyesters, acrylic polymers or urethane polymers and, for example, melamine, aldehyde- or isocyanate-curing agents. In order to reduce the friction of the coated surface, graphite or molybdenum disulfide is generally added as a solid lubricant. This is known, for example, from US-B 6,696,391.

  On the other hand, it is known from the prior art, for example from US-B 7,028,367, to mix additives for reducing friction with elastomeric materials for wiper rubber. Suitable additives include PTFE, graphite, boron nitrite, fluoro-polymer or fluoro-containing additives.

  The disadvantage of graphite as a solid lubricant contained in the coating is that the graphite particles reduce the bond strength and thus the wear strength of the coating. In many cases, the proportion of graphite exceeds the critical pigment volume concentration of the coating, which leads to low adhesion and thus insufficient wear strength of the coating. In order to achieve low frictional properties of the coated surface, a high content of graphite is required.

  The polyethylene-, polypropylene- or polytetrafluoroethylene-powder used to reduce the frictional resistance of the coating migrates to the surface of the coating, thereby achieving its lubricating action. However, it is disadvantageous that the powder can be easily separated from the coated surface due to lack of adhesion.

  In addition, waxes having a low melting point are also used as lubricants. The wax moves to the surface of the coating during thermal curing of the coating. When the coating is cooled, a thin surface enriched with wax is produced on the coating. Thereby, the friction of the wiper rubber is reduced. However, it is disadvantageous that waxes with a low melting point soften, especially in high temperature environments, for example when the wax is exposed to sunlight, thereby degrading its frictional resistance and wear resistance. Particularly in this case, the wax having a low melting point can remain attached to the windshield during operation of the window wiper. In contrast, a wax having a high melting point provides the advantage that it does not soften even when exposed to sunlight. However, waxes with a high melting point are disadvantageous in that they do not form a consistent film on the coated surface.

DISCLOSURE OF THE INVENTION The process according to the invention for producing a coated elastomer profile having a base substrate made of an elastomeric material comprises the following steps:
(A) applying a coating material to a base substrate made of an elastomer material, wherein the coating material contains a lubricant containing a polymer material;
(B) a step of heating the base substrate provided with the coating material to a temperature exceeding the melting temperature of the polymer material contained in the lubricant, wherein a polymer film is formed on the surface of the elastomer profile To
(C) A step of irradiating the elastomer profile and curing the polymer film is included.

  By coating the base substrate with a coating material containing a lubricant, good friction properties of the elastomer profile are achieved. Curing of the polymer film increases the wear resistance of the coating.

  The elastomer profile may be, for example, an extruded, injection molded or compression molded profile.

  In one embodiment, the polymeric material included in the lubricant acts as a lubricating substance. Usually the polymeric material is contained in a binder. As the binder, for example, polyacrylate, polyurethane, polyester-polyurethane, polyether-polyurethane, polyester, polyamide, and polyamideimide are suitable.

  In a second embodiment, the lubricant contains a solid lubricating material present in the form of particles, the particles being at least partially coated with a polymeric material.

  In step (b), by heating the base substrate with the coating material to a temperature above the melting temperature of the polymer material, the polymer material moves to the surface of the coating where it melts. As a result, a film made of a polymer material is formed on the surface of the coating material. Curing of the polymer film in step (c) results in a firm surface that has improved wear properties and similarly improved friction properties. When the lubricant contains a solid lubricating material, the material is retained in the coating by a cured polymer film. It is avoided that the material is removed from the coating by abrasion.

  In one embodiment of the present invention, the polymeric material included in the coating material is a wax having a low melting point. Waxes having a low melting point have the property that they tend to diffuse to the surface of the coating during curing of the coating material at elevated temperatures. However, the wax having a low melting point does not reduce the friction value sufficiently, and furthermore, the abrasion resistance is negligible, so a surface treatment is necessary to achieve the desired properties. This is achieved by curing by irradiation a wax having a low melting point deposited on the surface. This forms a wax with a high melting point that also has good friction properties and even improved wear properties.

  Suitable waxes contained in the coating material are, for example, paraffin wax, carnauba wax, microcrystalline wax or Fischer-Tropsch wax.

  In another embodiment, the polymeric material is selected from polyethylene (LDPE, LLDPE, HDPE), polypropylene, polytetrafluoroethylene, polyamide, PTFE modified polyethylene.

  The polymer likewise has the property of forming a film on the surface upon curing of the coating material. Furthermore, the polymers can be crosslinked by irradiation and can thus be cured. For example, it is known that cross-linking occurs upon irradiation of low density polyethylene (LDPE) by electron beam curing, and this cross-linking improves wear resistance and lubrication properties as well as thermal properties such as melting range. Curing is known from the prior art and is achieved by a reaction path based on intermediate formation of double bonds in the polyolefin chain by irradiation. For example, the addition of an additive can increase the crosslinking rate. As an additive, for example, triallyl isocyanurate (TAIC) is suitable.

  In a preferred embodiment of the invention, a wax having a low melting point is used as the polymer material, which can be cured similarly to LDPE by electron beam curing. Cross-linking of the wax layer on the surface by electron beam curing increases the melting point, thereby providing improved hardness, improved lubrication properties, improved wear resistance and increased wax transition temperature. Such wax is, for example, paraffin wax or microcrystalline wax.

  When a solid lubricant is included in the coating material, the lubricant is advantageously selected from graphite, polytetrafluoroethylene, molybdenum disulfide or mixtures thereof. Other suitable solid lubricants are, for example, talc, polyamide powder or polyethylene powder.

  As the elastomeric material for the elastomer profile, all elastomeric materials having the properties necessary for the field of use of the elastomer profile are suitable. Natural rubber (NR), chloroprene rubber (CR), ethylene-propylene-terpolymer (EPDM), ethylene-propylene-rubber (EPM), polyurethane, butyl rubber, nitrile rubber, silicone rubber and thermoplastic elastomer (TPE) and from these Elastomeric materials for elastomeric profiles selected from a mixture of are advantageous.

  In order to cure the polymer film, it is possible to irradiate gamma rays in addition to the above-described irradiation of the electron beam onto the elastomer profile. The advantage of gamma rays over electron rays is that gamma rays penetrate further into the coating. Thereby, the polymer material contained in the coating is hardened more deeply.

  The invention further relates to an elastomer profile having a base substrate made of an elastomeric material, including a coating made of a coating material containing a lubricant containing at least one polymeric material. According to the invention, the coating has a first layer of coating material, on which a second layer is formed, the second layer being essentially crosslinked. Contains polymer material.

  An advantage over the coatings known from the prior art is that the second layer containing an essentially cross-linked polymeric material has improved frictional properties and improved wear properties. Thereby, for example, the stability of the elastomer profile used as a wiper rubber is enhanced.

  In a first embodiment, the polymeric material that is crosslinked on the surface of the coating forms a lubricating material. However, it is also possible for the lubricant to contain a solid lubricant. The lubricating material is generally present at least partially on the surface of the coating, thereby reducing friction.

  The elastomer profile produced by the method according to the invention or the elastomer profile according to the invention is, for example, a wiper rubber for window squeegees, for example for car window wipers or for cleaning window glass at home. Used as. Other fields of application of the elastomer profile produced according to the invention are, for example, door seals, windshield seals, vehicle window seals, elastomer seals, O-rings, elastomer seal profiles, elastomer guide profiles. .

The figure which shows the cross section of the elastomer profile material which has a coating | cover. The figure which shows the schematic diagram of the manufacturing method of the coated elastomer profile material.

To form Figure 1 embodiment of the invention, showing the elastomeric profile having a coating formed by the present invention.

  An elastomer profile 1 having a coating formed according to the invention comprises a base substrate 3. The base substrate 3 is generally a deformed material manufactured by an extrusion method, an injection molding method, or a compression molding method. Usually, the base substrate 3 is manufactured from an elastomer material. As the elastomeric material for the base substrate 3, those mentioned above, for example NR, CR, EPTM, EPM or mixtures thereof, are suitable. When the base substrate 3 is used as a wiper rubber of a window wiper, the friction value between the above-described elastomer profile 1 used as the wiper rubber and the window on which the window wiper is used is reduced. Is desirable. A lower friction value results, for example, in reduced driving noise. Lower friction values are achieved according to the invention by applying a coating 5 on the base substrate 3. According to the invention, the coating 5 contains a polymer material, which forms a polymer film on the surface of the coating 5 when the coating 5 is cured. In order to achieve the desired friction and wear properties, the polymer film is cured by irradiation of the elastomer profile 1.

  The cross-section of the coated elastomer profile 1 shown in FIG. 1 shows two wiper rubbers, which are first produced as elastomer profile 1. In order to produce individual window wipers, it is necessary to separate the elastomer profile 1 along its centerline 7. Two individual wiper rubbers are produced from the elastomer profile 1. It is possible to coat the elastomer profile containing two wiper rubbers, or to separate the elastomer profile 1 first at the center line 7 and finally to coat it.

  FIG. 2 schematically shows a method for producing an elastomer profile formed according to the present invention.

  In the first step, the coating material 11 is applied to the base substrate 3. The coating material 11 contains a lubricant 13 containing a polymer material. The lubricant 13 is preferably dispersed in the binder. In this case, the lubricant 13 is preferably present in the form of small particles distributed in the binder.

  As binder for the coating material, any binder used for coating known to those skilled in the art is suitable. However, care must be taken here that the binder adheres to the elastomeric material of the base substrate 3, so that the coating 5 cannot be peeled off from the base substrate 3. Adhesion can also be improved by adding an adhesion promoter in the coating material. In contrast, it is also possible to first apply an adhesion promoter to the base substrate 3. Suitable adhesion promoters are, for example, chlorinated polymers in organic solvents.

  As the binder, polyacrylate resin, polyurethane resin, polyester-polyurethane resin, polyether-polyurethane resin, polyester resin, polyamide resin, and polyamideimide resin are particularly suitable. The resin may be crosslinked using, for example, a methylated iminomelamine aminoplast crosslinking agent, an isocyanate crosslinking agent, or an epoxide crosslinking agent.

  The polymer material contained in the lubricant 13 is, for example, wax or polyolefin. Furthermore, polytetrafluoroethylene or crosslinkable polyamide is also suitable. In particular, polytetrafluoroethylene and crosslinkable polyamide can be used simultaneously as lubricants for lubricants. However, in one embodiment, the lubricant 13 contains a solid lubricant. For example, graphite or molybdenum disulfide is used as the solid lubricant.

  After applying the coating material 11 on the elastomer material of the base substrate 3, the coating material 11 is cured. The curing is generally performed by supplying heat. Due to the heating of the coating material 11, the particles of the lubricant 13 dispersed in the coating material 11 rise to the surface of the coating material 11. Thereby, the 1st layer 15 which is mounted on the base substrate 3 and contains the binder of the coating material 11 essentially is formed. On the first layer 15, a second layer 17 containing essentially the lubricant 13 is formed. In this way, a surface having a low friction value is produced on the base substrate 3.

  From the second layer 17 produced by the movement of the particles of lubricant 13 to the surface of the coating, the contained lubricant particles, for example graphite particles, molybdenum disulfide particles, are activated after the binder has been cured. May be further removed because the adhesion between the polymeric material forming the second layer and the lubricant particles is not sufficiently high. It is possible that the second layer 17 is removed by abrasion due to the movement of the window wiper on the windshield. This is especially true when the polymer material used is soft, for example in the case of a soft wax layer. A characteristic of a soft wax layer is in particular that it has a low softening point, which facilitates removal by abrasion and transfer of the wax to the windshield.

  Therefore, in order to stabilize the second layer 17 and keep the lubricating substance in the second layer 17, according to the invention, the coating 17 is irradiated to cure the second layer 17. The irradiation of the second layer 17 is performed by, for example, an electron beam or a gamma ray. For this purpose, the coating 5 is applied to the irradiation device 19 and the irradiation line 21 is applied to the coating 5 from the device. For irradiation, both electron beams and gamma rays are suitable.

  When an electron beam is used for irradiation of the coating 5, on the surface of the second layer 17, a bond is formed between the polymer molecules contained in the layer, thereby cross-linking the polymer molecules. The polymeric material contained in the second layer 17 is cured resulting in a cured layer 23. By curing the second layer 17, the surface of the coated elastomer profile 1 is stabilized. The polymer material can no longer be easily removed by abrasion. Furthermore, the particles of lubricating material are better retained in the cured layer 23. The particles can no longer be easily removed. In this way, the lubricating action of the coated elastomer profile 1 is also improved and the friction value is continuously reduced.

  Unlike electron beams, gamma rays penetrate deeper into the second layer 17. The cured layer 23 occupies a greater thickness than when cured by the irradiation beam 21 with an electron beam.

  Since the curing of the second layer 17 to the cured layer 23 is performed by an electron beam or a gamma ray, the polymer material contained in the lubricant 13 and forming the second layer 17 is an electron beam or a gamma ray. All polymeric materials that can be cured by irradiation are suitable. Suitable polymers are in particular polyolefins such as polypropylene (PP), polyethylene (HDPE, LDPE, LLDPE) and other polymeric materials such as polytetrafluoroethylene (PTFE) and crosslinkable polyamides. In particular, the last ones can also act as lubricants at the same time, so when using polytetrafluoroethylene or crosslinkable polyamides, further solid lubricants such as graphite or molybdenum disulfide are used. There is no need.

  Since the frictional value of the elastomer profile 1 is reduced by the surface coating, the elastomer profile 1 is applied to the elastomer profile in the same manner as in, for example, a window wiper of an automobile or a window squeegee as used at home. It can be used wherever the profile 1 is guided through other surfaces.

Claims (14)

The following steps:
(A) A step of applying the coating material (11) to the base substrate (3) made of an elastomer material, wherein the coating material (11) contains a lubricant (13) containing a polymer material. ,
(B) a step of heating the base substrate (3) provided with the coating material (11) to a temperature above the melting temperature of the polymer material contained in the lubricant (13), wherein the polymer film (17) is Shall be formed on the surface of the elastomer profile,
(C) A method for producing a coated elastomer profile (1) having a base substrate (3) made of an elastomer material, comprising irradiating the elastomer profile and curing the polymer film (17).   2. The method according to claim 1, wherein the polymeric material contained in the lubricant (13) acts as a lubricating substance.   The method according to claim 1, wherein the lubricant (13) comprises a solid lubricating substance present in the form of particles, the particles being at least partially coated with a polymeric material.   4. A method according to any one of claims 1 to 3, wherein the polymeric material is a wax having a low melting point.   The method according to claim 4, wherein the wax is paraffin wax or microcrystalline wax.   4. A process according to claim 1, wherein the polymeric material is selected from polyethylene, in particular LDPE, LLDPE, HDPE, polypropylene, polytetrafluoroethylene, polyamide or PTFE-modified polyethylene.   7. A process according to any one of claims 3 to 6, wherein the solid lubricant is selected from graphite, polytetrafluoroethylene, molybdenum disulfide, talc, polyamide powder, polyethylene powder or mixtures thereof.   The elastomeric material for the base substrate (3) is natural rubber, chloroprene rubber, ethylene-propylene-terpolymer, ethylene-propylene-rubber, polyurethane, butyl rubber, nitrile rubber, silicone rubber, thermoplastic elastomer and mixtures thereof The method according to claim 1, wherein the method is selected from:   The method according to any one of claims 1 to 8, wherein irradiation with an electron beam or gamma ray is performed in the step (c).   In an elastomer profile having a base substrate (3) made of an elastomeric material, comprising a coating (5) made of a coating material (11) containing a lubricant (13) containing at least one polymer material. ) Has a first layer (15) made of a coating material (11), a second layer (17) is formed on the first layer (15), and the second layer (17 ) Containing an essentially cross-linked polymeric material.   The lubricant (13) further contains a solid lubricant, which is preferably selected from graphite, polytetrafluoroethylene, molybdenum disulfide, talc, polyamide powder, polyethylene powder or mixtures thereof. The elastomer profile material according to claim 10.   12. Elastomeric profile according to claim 10 or 11, wherein the polymeric material is selected from polyethylene, in particular LDPE, LLDPE, HDPE, polypropylene, polytetrafluoroethylene, polyamide, PTFE-modified polyethylene, or a wax having a low melting point.   The elastomeric material of the base substrate (3) is selected from natural rubber, chloroprene rubber, ethylene-propylene-terpolymer, ethylene-propylene-rubber, polyurethane, butyl rubber, nitrile rubber, silicone rubber, thermoplastic elastomer and mixtures thereof The elastomer profile according to any one of claims 10 to 12, which is formed.   As an O-ring, as an elastomer seal member, as an elastomer seal member, as a window seal material in vehicles, as a windshield seal material, as a wiper rubber for window wipers or window squeegees of automobiles An elastomer profile of any one of claims 10 to 13 or produced by the method of any one of claims 1 to 9, as an elastomer guide profile. Use of material (1).

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