DE102009003798A1 - Power transmission belt e.g. V-belt, for use in automobile area, has coating that is formed from elastomer matrix that includes conductive or conductive coated particles i.e. functional pigments - Google Patents

Abstract

The belt (10) has a top layer (11) as a belt rear and an underbody (13) with a power transmission zone (14), where the top layer and the power transmission zone are provided with coatings (15, 16). The coating is formed from an elastomer matrix that includes conductive or conductive coated particles i.e. functional pigments. The coating is free from polycyclic aromatic hydrocarbons. The coating is formed from an elastomer matrix, which includes a non-polar elastomer and a bright filler i.e. silicic acid. An independent claim is also included for a method for manufacturing a power transmission belt.

Description

The The invention relates to a power transmission belt with a elastic body, comprising a cover layer as a belt back and a substructure with a power transmission zone, wherein the power transmission zone and / or the cover layer with a Coating is or are provided. The invention further relates a method for producing such a drive belt.

• DE 38 23 157 A1
• DE 100 16 351 A1
• DE 10 2006 007 509 A1
• EP 0 590 423 A2
• EP0737228B1
• EP0831247B1
• EP 0 866 834 B1
• EP 1 108 750 A1
• EP 1 129 308 B1
• US 3 981 206

Power transmission belts, which are also referred to as drive belts and are closed endlessly in the functional state, can be designed as flat belts, V-belts, V-ribbed belts and toothed belts. Of particular importance are the V-belt and the V-ribbed belt, reference being made in this regard in particular to the following patent literature:

• DE 38 23 157 A1
• DE 100 16 351 A1
• DE 10 2006 007 509 A1
• EP 0 590 423 A2
• EP0737228B1
• EP0831247B1
• EP 0 866 834 B1
• EP 1 108 750 A1
• EP 1 129 308 B1
• US 3,981,206

The Elasticity including flexural elasticity a power transmission belt is achieved in that the main body and thus the top layer and the substructure consist of a polymeric material with elastic properties, Here, in particular, the two material groups elastomers and thermoplastic elastomers (TPE) are mentioned.

Of the Elastic body is also mostly with a embedded reinforcements or tension members provided, which can be implemented in one or more layers.

various Power transmission belts must be conductive or be antistatic around in potentially explosive areas to be used. For example, in applications especially in the automotive sector by sparking no interference from radio reception occur. Also are non-conductive Particles extending from the belts in operation by the existing Loosen abrasion even with good abrasion resistance can be dangerous because they are in critical Abandon machine parts.

to Achievement of surface conductivity in rubber articles For many years carbon black has been used as standard. The soot forms within a certain concentration within of elastomer blends a network that excels in electricity and can conduct reliably.

As is well known, the use of soot causes that the corresponding rubber products are consistently black are colored. Furthermore, they always contain polycyclic aromatic hydrocarbons which are not for environmental reasons are desired.

The same applies to power transmission belts, such as toothed belts and jacketed V-belts, where the functional surfaces are constructed of fabric. If a conductivity is to be achieved here by a coating with soot-containing elastomer mixtures, then these belts can not be colored in color. This is representative of more writings among others US6770004 B1 seen.

An alternative to carbon black, in particular in the case of fabric coatings, is elastomer mixtures which use only carbon black or carbon black mixed with graphite. Also possible is the use of conductive carbon fibers, such as in US6004238A1 described. However, a colored design of the belt is not given with these possibilities.

Become in the elastomer blend polar rubbers such. B. polychloroprene (CR) or nitrile butadiene rubber (NBR), so often are used to achieve antistatic properties. Mixtures of polar Plasticizers and ionic silicates used. Polar softeners are mostly glycols, glycol esters or glycol ethers, while As silicates mostly metal silicates or alkaline earth silicates used become. The conductivity of these mixtures is always one Internal conductivity, at which the free ions of the silicates be transported with the polar plasticizers. These conductivities do not work in non-polar rubber compounds, which on the basis of natural rubber (NR), butadiene rubber (BR) and / or Styrene butadiene rubber (SBR, SSBR, ESBR).

isolated Conductivities are also due to the addition of metal powder or metal threads. But you have to always at least 30% by volume of these particles to be present to ensure good conductivity. This makes a colored design of a rubber article, in particular one Belt, very difficult if possible at all is still possible.

For not dynamically charged articles it is known that conductivities be achieved by in itself non-conductive mineral base particles with metal or metal oxide coatings be applied.

For example, bets are placed in EP0960912 in paints, in US5552190 as a surface coating of golf balls, in US4921751 described in tissue coatings. It has been assumed that the use in dynamically extremely loaded articles, such. B. drive belt, is not possible because the coated particles are destroyed by the dynamic movement in the belt and so the conductivity is lost.

It Therefore, the object of the present invention is a power transmission belt which has a surface layer which is good conductive and colorable is possible without any loss of regard Dynamic resilience and longevity to accept. At the same time, the conductivity is supposed to be longer Maintain load and the power transmission belt be free of polycyclic aromatic hydrocarbons.

Solved This task is characterized by the fact that the power transmission belt contains at least one coating, which consists of a Elastomer matrix is constructed, wherein the elastomer matrix conductive and / or contains conductive coated particles.

Surprisingly it was found that a power transmission belt, which contains at least one coating which consists of an elastomer matrix is constructed, wherein the elastomer matrix conductive and / or contains conductive coated particles, themselves characterized by a good electrical conductivity and can be colored at the same time.

By the use of conductive and / or conductive coated particles can be used to obtain conductivity completely on dark fillers, especially on Soot, to be dispensed with. Furthermore, it is becoming apparent such power transmission belt by a conductivity that will get over a long life of the belt remains.

in the Subsequently, the mentioned coating is also used as a surface layer or referred to as a surface coating.

Of the Power transmission belt includes at least one such surface layer. This may be the case Surface layer of the cover layer or around the surface layer the power transmission zone act. In a preferred Embodiment is the power transmission belt completely provided with a surface layer. Here the expert person speaks of a sheathing, in particular a complete sheath.

In a preferred embodiment, the coating is conductive with a surface resistance less than or equal to 10 ⁷ ohms.

For the purpose of better sustainability and environmental compatibility is the Coating advantageously free of polycyclic aromatics.

This On the one hand achieved by the coating advantageously free of carbon blacks, on the other hand, the coating is preferred additionally free from mineral processing oils, in addition to carbon black another source of polycyclic hydrocarbons are.

Around to achieve a further improved environmental compatibility, is in a particular embodiment of the invention of complete power transmission belt free of soot.

This means in particular that also the main body and the other components of the belt are free of soot.

to further avoidance of polycyclic hydrocarbons the main body and the other components of the belt free of mineral processing oils.

Of Furthermore, it has been found to be particularly advantageous if the Elastomer matrix, from which the coating is built, a non-polar Contains elastomer.

This is in particular selected from the group consisting of natural polyisoprene and / or synthetic polyisoprene and / or butadiene rubber and / or styrene-butadiene rubber and / or solution-polymerized styrene-butadiene rubber and / or emulsion-polymerized styrene-butadiene rubber and / or halobutyl rubber and / or Polynorbomene and / or isoprene-isobutylene copolymer and / or ethylene-propylene-diene rubber and / or styrene-isoprene-butadiene terpolymer and / or isoprene-butadiene copolymer and / or hydrogenated styrene-butadiene rubber.

The said nonpolar elastomers can be uncut or blended with at least one other of said elastomers be.

Of Furthermore, it is possible that the non-polar elastomer functionalized or modified. It is preferred, however, if the elastomer matrix between 50 and 100 phr of natural and / or synthetic polyisoprene (NR or IR).

The term phr (parts per hundred parts by rubber by weight) is the usual quantity in the rubber industry for mixture recipe The dosage of the parts by weight of the individual substances is always based on 100 parts by weight of the total mass of all the rubbers present in the mixture.

In terms of the composition and structure of the body and the possibly contained reinforcement layer the power transmission belt is at this point on the referred to the general state of the art.

The Coating is constructed of an elastomeric matrix, which at least contains a light filler, wherein it is preferably silica.

The silicas used in the rubber industry are generally precipitated silicas, which are characterized in particular according to their surface. To characterize the nitrogen surface (BET) according to DIN 66131 and DIN 66132 as a measure of the inner and outer filler surface in m ² / g and the CTAB surface according to ASTM D 3765 as a measure of the outer surface, which is often considered the rubber-effective surface, in m ² / g. Advantageously, silicas having a nitrogen surface area greater than or equal to 100 m ² / g, preferably between 120 and 300 m ² / g, more preferably between 140 and 250 m ² / g, and a CTAB surface between 100 and 250 m ² / g, preferably between 120 and 230 m ² / g and particularly preferably between 140 and 200 m ² / g used.

When but bright fillers can also be those of the expert Person known, such as. As chalk, talc, alumina, etc., used become.

If a coupling agent, in the form of silane or an organosilicon compound, is used in the elastomer matrix, the amount of coupling agent is 0-20 phr, preferably 0.1-15 phr, more preferably 0.5-10 phr. All coupling agents used by the person skilled in the art for use in rubber mixtures can be used as coupling agents. Particularly noteworthy here are mercaptosilanes and in particular those which are distinguished by a reduction in the volatile organic constituents, as they are, for example, for further documents, in DE 10 2005 057 801 . WO99 / 09036 . WO2002 / 048256 and WO2006 / 015010 can be found.

One important idea of the invention is that the elastomer matrix of the Coating free of dark fillers, in particular is free of soot.

Just then it is possible the power transmission belt to make colored.

The Elastomer matrix from which the coating is constructed contains preferably conductive coated particles. This acts it is in a particularly preferred embodiment so-called functional pigments, in particular based of inorganic compounds, especially minerals.

pigments are practically insoluble substances in the application medium, and are used as colorants or because of their anti-corrosive, magnetic, electrical or electromagnetic properties used. Pigments with latter properties are considered functional Called pigments. Most of this functional Pigments is based on inorganic compounds.

Some These functional pigments are based on the layer-substrate principle. Here comes as a substrate in most cases, the mineral Mica in the form of thin platelets for use, while the layers on the mica flakes consist of metal oxides, the carriers of the functional Properties are. Preferably, in the present invention such pigments are used.

Pigments with such a design principle are available, for example under the name Minatec ^® from Merck.

to Color design, the elastomer matrix can be colored pigments, preferably added based on organic compounds become.

Farther The elastomer matrix contains other additives.

Further Additives essentially comprises the crosslinking system (crosslinker, Sulfur donors and / or elemental sulfur, accelerators and Retarder), antiozonants, anti-aging agents, masticating agents and more activators. The proportion of the total amount of others Additives is 3 to 150 phr, preferably 3 to 100 phr and more preferably 5-80 phr.

In the total amount of other additives are still 0.1-10 phr, preferably 0.2-8 phr, more preferably 0.2-4 phr, zinc oxide. It is customary to add zinc oxide as activator, usually in combination with fatty acids (eg stearic acid), to an elastomer matrix for the sulfur crosslinking with vulcanization accelerator. The sulfur is then activated by complex formation for vulcanization. The conventionally used zinc oxide generally has a BET surface area of less than 10 m ² / g. But it can also be so-called nano-zinc oxide with a BET surface of 10 to 60 m ² / g are used.

The Vulcanization of the elastomer matrix is preferably in the presence performed by elemental sulfur or sulfur donors, some sulfur donors at the same time as a vulcanization accelerator can act. Elemental sulfur or sulfur donor become the expert in the final mixing step common amounts (0.4 to 9 phr, elemental sulfur preferably in amounts of 0 to 6 phr, more preferably in amounts from 0.1 to 3 phr) was added to the rubber composition.

Of the Power transmission belt is used as a flat belt, V-belts, V-ribbed belts and toothed belts, whereby the V-belt, in particular the coated V-belt, is particularly preferred.

A Another object of the invention is a process for the preparation a power transmission belt to provide, in which the requirement profile mentioned above is guaranteed.

• – Einseitiges Beschichten eines Gewebes, Gewirkes oder Geleges mit einer Klebebeschichtung;
• – Beschichten der zweiten Seite des Gewebes, Gewirkes oder Geleges mit einer Elastomermatrix welche leitfähige und/oder leitfähig beschichtete Partikel enthält;
• – Zusammenfügen des beidseitig beschichteten Gewebes, Gewirkes oder Geleges mit einer Basismischung und dadurch Aufbau des Kraftübertragungsriemens;
• – Vulkanisation des Kraftübertragungsriemens.

This problem is solved by at least the following method steps:

• - One-sided coating of a fabric, knitted fabric or Geleges with an adhesive coating;
• - Coating the second side of the fabric, knitted fabric or Geleges with an elastomeric matrix containing conductive and / or conductive coated particles;
• - Assembling the coated on both sides fabric, knitted fabric or Geleges with a base mixture and thereby construction of the power transmission belt;
• - Vulcanization of the power transmission belt.

Prefers Tissue is a cotton fabric.

One such manufactured power transmission belt shows a good conductivity over a long lifetime, is colorful in design and is preferred as a V-belt, in particular as jacketed V-belt, use.

The Invention will now be described with reference to two experimental examples of a jacketed V-belt presented in more detail:

Experimental Example 1

Adhesive coating:

• 70 phr NO
• 30 phr SBR
• 45 phr of silica
• 4 phr of silane, Si69, Fa Evonik
• 3 phr anti-aging agent
• 25 phr adhesive resin
• 5 phr zinc oxide
• 2 phr vulcanization accelerator, CBS
• 2 phr sulfur

Conductive coating:

• 80 phr NO
• 20 phr SBR
• 20 phr of silica
• 1 phr of silane, Si69, Fa Evonik
• 3 phr anti-aging agent
• 10 phr adhesive resin
• 100 phr functional pigment, Minatec.RTM ^® 40 cm, Merck
• 4 phr of organic color pigment, Oppasin blue 6470, Fa BASF
• 5 phr zinc oxide
• 2 phr vulcanization accelerator, CBS
• 2 phr insoluble sulfur

Basic mix of the belt:

• 70 phr NO
• 30 phr SBR
• 45 phr of silica
• 50 phr chalk
• 5 phr cotton short fibers
• 4 phr of silane, Si69, Fa Evonik
• 3 phr anti-aging agent
• 25 phr adhesive resin
• 5 phr zinc oxide
• 2 phr vulcanization accelerator, CBS
• 2 phr sulfur

One Cotton fabric becomes one-sided with the adhesive coating which dissolved in toluene, coated, then finds the coating on the opposite side the conductive coating, also dissolved in toluene, instead of.

With This fabric becomes a jacketed belt with the base mix built and vulcanized.

conductivities:

• fresh belt: 1,000 ohms
• after 10 hours continuous operation: 8,000 ohms
• after 27 hours of continuous operation: 10,000 ohms

Experimental Example 2

An aqueous emulsion based on SBR / NBR latex, azo dye, 50 phr functional pigment (Minatec ^® 40 CM) and butoxyethanol is painted on one side of a cotton fabric. The fabric is dried and removed from the ge opposite side provided with the above-mentioned adhesive coating.

• frischer Riemen: 5.000 Ohm
• nach 10 Stunden Dauerbetrieb: 12.000 Ohm
• nach 27 Stunden Dauerbetrieb: 15.000 Ohm

An analogous structure of a belt shows the following conductivities:

• fresh belt: 5,000 ohms
• after 10 hours of continuous operation: 12,000 ohms
• after 27 hours of continuous operation: 15,000 ohms

The Invention will now be based on embodiments below Referring to schematic drawings explained. Show it:

1 a longitudinal section through a toothed belt with a coating for the power transmission zone and for the cover layer.

2 a cross section through a V-belt which is covered by a coating.

10

belt (Toothed belt)

11

topsheet as a belt back

12

strengthening support in the form of tension strands

13

substructure

14

Power transmission zone

15

coating the power transmission zone

16

coating the top layer

17

tension cord

18

base rubber (elastic body)

19

coating

20

belt (Sheathed V-belt)

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 3823157 A1 [0002]
• - DE 10016351 A1 [0002]
• DE 102006007509 A1 [0002]
• - EP 0590423 A2 [0002]
• - EP 0737228 B1 [0002]
• - EP 0831247 B1 [0002]
• - EP 0866834 B1 [0002]
• - EP 1108750 A1 [0002]
• - EP 1129308 B1 [0002]
• US 3981206 [0002]
• - US 67700041 B [0008]
• - US 6004238 A1 [0009]
• - EP 0960912 [0013]
• US 5552190 [0013]
• US 4921751 [0013]
• - DE 102005057801 [0035]
• WO 99/09036 [0035]
• WO 2002/048256 [0035]
• WO 2006/015010 [0035]

Cited non-patent literature

• - DIN 66131 [0033]
• - DIN 66132 [0033]
• ASTM D 3765 [0033]

Claims (19)

Power transmission belt ( 10 . 20 ) with an elastic base body ( 18 ), comprising a cover layer ( 11 ) as a belt back and a substructure ( 13 ) with a power transmission zone ( 14 ), the power transmission zone ( 14 ) and / or the cover layer ( 11 ) with a coating ( 15 . 16 . 19 ), characterized in that the coating ( 15 . 16 . 19 ) is constructed of an elastomer matrix, wherein the elastomer matrix contains conductive and / or conductive coated particles. Power transmission belt according to claim 1, characterized in that the coating ( 15 . 16 . 19 ) is conductive, wherein the surface resistance is less than or equal to 10 ⁷ ohms. Power transmission belt according to claim 1 or 2, characterized in that the coating ( 15 . 16 . 19 ) is free of polycyclic aromatic hydrocarbons. Power transmission belt according to one of claims 1 to 3, characterized in that the coating ( 15 . 16 . 19 ) is constructed of an elastomeric matrix containing a non-polar elastomer. Power transmission belt according to claim 4, characterized characterized in that the nonpolar elastomer is selected is from the group consisting of natural polyisoprene and / or synthetic polyisoprene and / or butadiene rubber and / or styrene-butadiene rubber and / or solution-polymerized styrene-butadiene rubber and / or emulsion-polymerized styrene-butadiene rubber and / or halobutyl rubber and / or polynorbornene and / or isoprene-isobutylene copolymer and / or ethylene-propylene-diene rubber and / or styrene-isoprene-butadiene terpolymer and / or isoprene-butadiene copolymer and / or hydrogenated styrene-butadiene rubber. Power transmission belt according to one of claims 1 to 5, characterized in that the coating ( 15 . 16 . 19 ) is constructed of an elastomeric matrix containing at least one light filler. Power transmission belt according to one of the claims 1 to 5, characterized in that the light filler Silica is. Power transmission belt according to one of claims 1 to 7, characterized in that the coating ( 15 . 16 . 19 ) is constructed of an elastomeric matrix which is free of dark fillers. Power transmission belt according to claim 8, characterized in that the coating ( 15 . 16 . 19 ) is constructed of an elastomeric matrix which is free of soot. Power transmission belt according to one of claims 1 to 9, characterized in that the coating ( 15 . 16 . 19 ) is constructed of an elastomer matrix containing conductive coated particles. Power transmission belt according to claim 10, characterized characterized in that the conductive coated particles functional pigments are. Power transmission belt according to claim 11, characterized characterized in that the functional pigments are based on inorganic Connections are. Power transmission belt according to one of claims 1 to 12, characterized in that the coating ( 15 . 16 . 19 ) is colored. Power transmission belt according to one of Claims 1 to 13, characterized in that it is in the form of a V-belt ( 20 ) is trained. Power transmission belt according to claim 14, characterized in that the V-belt ( 20 ) is sheathed. Power transmission belt according to one of claims 1 to 15, characterized in that the power transmission belt ( 10 . 20 ) is completely free of soot. Method for producing a power transmission belt ( 10 . 20 ) with an elastic base body ( 18 ), comprising a cover layer ( 11 ) as a belt back and a substructure ( 13 ) with a power transmission zone ( 14 ), the power transmission zone ( 14 ) and / or the cover layer ( 11 ) with a coating ( 15 . 16 . 19 ), characterized by at least the following method steps: - one-sided coating of a woven fabric, knitted or laid fabric with an adhesive coating; - Coating the second side of the fabric, knitted fabric or Geleges with an elastomeric matrix containing conductive and / or conductive coated particles; - Assembling of the coated on both sides fabric, knitted fabric or Geleges with a base mixture and thereby construction of the power transmission belt ( 10 . 20 ); - vulcanization of the power transmission belt ( 10 . 20 ). Method according to claim 17 for the production of a V-belt ( 20 ). Process according to claim 17 for the production of a coated V-belt ( 20 ).