Patent Application
20120145275
The invention relates to a hose with at least the following layer structure:
In the past, much attention has been given to the development of the internal layer with properties of resistance to the substances to be conveyed, for example resistance to oils, fuels, chemicals, coolants, and gases, and this type of development will continue against the background of increasingly stringent requirements, inter alia with respect to additional barrier layers, in particular for gases. Reference is made by way of example to the following literature for the relevant prior art: DE 88 05 593 U1; DE 20 2004 020 354 U1; DE 42 15 778 A1; DE 10 2008 014 988 A1; U.S. Pat. No. 6,089,277; EP 0 826 915 A2; EP 1 764 211 A1; EP 1 546 595 B1; WO 2007/045322 A1; U.S. Pat. No. 4,998,564; U.S. Pat. No. 5,718,957; and, United States patent application publication 2005/0205149 A1.
More details of the prior art for charge-air hoses are given below, and particular reference is made here to the laid-open specification WO 2007/045322 A1.
Internal combustion engines for motor vehicles are divided according to their design into naturally aspirated engines in which hoses pass unpressurized air to the intake manifold and forced-induction engines using dynamic or external forced induction. In the case of engines with external forced induction, pressurized and heated air is fed through pipes and hoses to the cylinders downstream of the turbocharger, as is the case for example when an exhaust gas turbocharger is used. The advantages of forced induction to the engine, for example, increased engine power and engine torque, reduced fuel consumption, and reduced emissions of hazardous substances, can be further increased by cooling the charge air through a charge-air cooler between exhaust gas turbocharger and cylinder. Whereas exhaust gas turbochargers are components fixedly mounted on the engine, charge-air coolers have hitherto been secured to the bodywork. The charge-air hoses used for engines with charge-air cooling therefore have to compensate the relative movements between engine and bodywork.
Hoses for feeding air to engines of motor vehicles are divided, according to the nature of the air to be conveyed, into clean-air hoses and hoses for conveying air contaminated by engine oil, fuel vapor, fuel condensate, and exhaust gases from crank-case venting, from exhaust gas recirculation, and from the lubrication of the exhaust gas turbocharger. Charge-air lines and charge-air hoses have to be chemically resistant to engine oil and to pressurized and heated air, the temperature and pressure of which depend on the charge pressure and the charge-air cooling system. Compensation of assembly tolerances, absorption of relative movements between exhaust gas turbocharger/-charge-air cooler, and charge-air cooler/engine, and acoustic damping can be provided only by charge-air hoses that have dynamic stability.
In the prior art, charge-air hoses are produced from a crosslinked rubber mixture based on AEM (trade name “VAMAC”), and indeed this applies not only to the internal layer but also to the external layer. They feature good seating properties together with high dynamic functionality, but only if aminic crosslinking is used.
Charge-air hoses made of AEM with peroxidic crosslinking do not comply with the requirements relating to seating properties and dynamic functionality.
Charge-air hoses in which both the internal layer and the external layer are composed of an aminically crosslinked AEM rubber mixture in turn feature the following disadvantages:
The problems indicated here which apply to charge-air hoses are in principle relevant to all hoses based on aminically crosslinked AEM material.
Patent specification EP 1 546 595 B1 then proposes a hose, in particular a charge-air hose, which is intended to eliminate the abovementioned disadvantages. Its internal layer is composed of an aminically and/or peroxidically crosslinked rubber mixture based on AEM, ACM, or EVA. Between the internal layer and the external layer, the arrangement has an adhesive layer (intermediate layer) which is composed of a peroxidically crosslinked mixture of materials. Said mixture of materials is based on a rubber blend mixture, in particular based on an AEM/EPDM blend. However, there is an associated conflict here, to which some reference has already been made above:
In the light of all of the problems described here and of the conflict inherent in the objectives disclosed in patent specification EP 1 546 595 B1, the object of the invention consists in providing a hose of this generic type which features firstly an internal layer resistant to the substances to be conveyed and secondly an adhesive layer adhesively bonded to the internal layer, where said two base layers form the basis for a versatile hose structure, with a specific view to a variety of possible applications.
Said object is achieved in that
Particular significance is attached to an internal layer based on AEM material or on blended AEM material, specifically with a view to compatibility with another rubber component. The simple variant using unblended material is mostly adequate.
For the purposes of simple hose design, the adhesive layer can simultaneously form the external layer without any further layers superposed thereon, especially since EPM and EPDM feature high resistance to aging, to weathering, and to heat together with good low-temperature flexibility. These types of material protect the hose from exterior effects. However, this type of hose is used only when the substance to be conveyed is not a pressurized substance.
However, the hose is mostly provided with an external layer, in particular in conjunction with an embedded single- or multiple-ply reinforcing layer. The substance to be transported can thus be a pressurized substance. In this type of hose structure the adhesive layer takes the form of intermediate layer, specifically between the internal layer and the reinforcing layer or the external layer.
The external layer here is composed of a peroxidically crosslinked rubber mixture, in particular based on unblended EPM or on an EPM blend or on unblended EPDM or on an EPDM blend. In the case of the blend variant, a particular role is played by an EPM/EPDM blend with various proportions, for example, an EPM/EPDM blend with 30 phr of EPM and 70 phr of EPDM. However, the version using unblended material is mostly preferred. The particular advantages of EPM and EPDM in respect of exterior effects have been mentioned above.
The reinforcing layer has been formed from a woven or knit, in particular based on a textile material. The materials relevant here can be a polyamide (PA), a polyimide (PI), an aramid, in particular para-aramid or meta-aramid, a polyvinyl acetal (PVA), a polyether ether ketone (PEEK), a polyester, in particular polyethylene terephthalate (PET) or polyethylene 2,6 naphthalate (PEN), a polysulfone (PSU), or a polyphenylene or polyphenylene derivative, in particular a polyphenylene sulfide (PPS). It is also possible to use hybrid designs, for example taking the form of a mixed yarn. By way of example, a hybrid design made of PPS and PA is used for the purposes of a hose developed relatively recently (DE 10 2008 037 417.2). PPS is a high-performance material and contributes to high strength, while PA contributes not only to reinforcement but also, because it can be activated to provide adhesion, to improved adhesion with respect to the surrounding elastomeric material. In this context, the reinforcing layer is mostly in direct contact with the adhesive layer (intermediate layer) on one side and with the external layer on the other side, specifically with formation of an adhesive bond.
The crosslinking of the internal layer, adhesive layer or intermediate layer, and external layer is of essential significance and in particular involves a crosslinking agent system comprising a crosslinking agent and an accelerator or activator, and further detail is therefore given below concerning the crosslinking of the individual layers.
The internal layer is an aminically crosslinked layer, preferably involving exclusively aminic crosslinking. Patent specification EP 1 546 595 B1 describes the use of an aminic and/or peroxidic crosslinking agent, but details have been given above in the introduction concerning the disadvantages of peroxidic crosslinking of AEM-based rubber mixtures. Even a small proportion of peroxides, alongside the aminic crosslinking agent, is disadvantageous.
The aminic crosslinking agent is in particular a diamine, and HMD and/or HMDC is/are in particular used here. The proportion of the aminic cross-linking agent is from 0.3 phr to 2.1 phr, in particular from 0.8 phr to 1.6 phr, more particularly from 1.0 phr to 1.4 phr.
The accelerator or activator is a base, for example DPG, but in particular DBU or a DBU derivative. Reference is made in this connection to the relatively recent development in DE 10 2008 055 525.8. DBU replaces DOTG, which has hitherto often been used as accelerator but which has been classified as toxic and carcinogenic. DBU, in particular in conjunction with HMD and/or HMDC, and more particularly with HMDC, provides an ideal effect in terms of vulcanization rate and in terms of the shelf life of an AEM rubber mixture or ACM rubber mixture. The quantitative proportion of the accelerator is from 0.5 phr to 2.4 phr, in particular from 0.8 phr to 2.0 phr, more particularly from 1.0 phr to 1.8 phr.
The peroxidic crosslinking agent for the rubber mixture of the adhesive layer or intermediate layer is preferably an alkyl aralkyl peroxide and/or a diaralkyl peroxide and/or a peroxyketal and/or a peroxyester. Particular importance is attached to the use of dicumyl peroxide and/or
The activator is in particular an allyl compound and/or an acrylate and/or a diacrylate and/or a methacrylate and/or BR, in particular here in the form of 1,2-BR, and/or N,N′-m-phenylene-dimaleimide. From the group of the allyl compounds, particular mention may be made here of TAC, and also of derivatives. Compounds which play a role within the entire group of the acrylates, diacrylates, and methacrylates are not only the esters, such as MMA, but also the salt compounds, in particular in the form of zinc salt compounds. ZDMA is of particular importance. The quantitative proportion of the activator is from 0.1 phr to 20.0 phr, in particular from 1.0 phr to 15.0 phr, more particularly from 5.0 phr to 15.0 phr.
The information applicable to the peroxidically crosslinked rubber mixture in conjunction with the preferred hose structure made of internal layer, adhesive layer (intermediate layer), and external layer is the same as that provided for the adhesive layer or intermediate layer discussed above, specifically both in relation to the preferred types of substance for the crosslinking agent and activator and in relation to the quantitative proportions of these.
The rubber mixture of the internal layer and of the adhesive layer or intermediate layer, and of the external layer, comprises not only the crosslinking agent or crosslinking agent system but also further mixture ingredients. These comprise in particular a filler and/or a metal oxide and/or a plasticizer and/or a processing aid and/or an antioxidant and/or an adhesive. However, there is mostly at least one filler incorporated into the mixture.
The filler is a carbon black, for example an SAF carbon black, HAF carbon black, FF carbon black, FEF carbon black or lamp black, and/or a silica and/or a silicate and/or chalk and/or kaolin. Particular silicates that may be mentioned are an aluminum silicate and/or calcium silicate and/or a magnesium silicate. However, there is mostly at least one carbon black incorporated into the mixture.
Among the metal oxides, a particular role is played by CaO and/or MgO and/or ZnO.
The plasticizer is a mineral oil plasticizer and/or a polymer plasticizer and/or an ester plasticizer.
The adhesive comprises a tackifier and/or an adhesion promoter, for example a resin. It is thus possible that the internal layer and the adhesive layer or the intermediate layer, free from any additional application of adhesion promoter, form an adhesive bond. In one alternative, an adhesion-agent solution or a solvent can also be applied between said two layers.
The total quantitative proportion of the mixture ingredients, specifically without the crosslinking agent or the crosslinking agent system, is from 50 phr to 400 phr, in particular from 80 phr to 160 phr.
In relation to other aspects of the mixture ingredients, reference is made to the general prior art in rubber mixture technology.
The hose of the invention is used as follows to transport a substance to be conveyed:
Another object of the invention consists in providing a process which can produce a hose of this generic type in a manner which is simple and also inexpensive.
The following three process variants are used in relation to the internal layer and to the adhesive layer or intermediate layer bonded thereto:
The internal layer made of the aminically crosslinkable rubber mixture and the adhesive layer made of the peroxidically crosslinkable rubber mixture are formed in succession via extrusion.
The internal layer and the adhesive layer with the crosslinkable rubber mixtures as in variant A are formed via coextrusion.
The internal layer and the adhesive layer with the crosslinkable rubber mixtures as in variant A are respectively formed via calendering.
After the process substeps as in variants A, B, and C, the hose is then finished, specifically as follows:
The single- or multiple-ply reinforcing layer can by way of example be introduced by means of knitting processes, winding processes, or braiding processes. Winding processes using wovens coated by rubber mixtures can also be used. It is also possible to use a combination of extrusion processes and winding processes. In this connection, reference is made to the general prior art in process technology for producing textile-reinforced hoses.
The invention will now be described with reference to the single FIGURE of the drawing (
In this inventive example, the adhesive layer 3 represents an intermediate layer, and forms an adhesive bond with the internal layer 2.
If the hose is not subject to any stringent pressure requirements, the adhesive layer 3 can simultaneously form the external layer.
It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 026 254.7 | Jul 2009 | DE | national |
This application is a continuation application of international patent application PCT/EP 2010/058686, filed Jun. 21, 2010, designating the United States and claiming priority from German application 10 2009 026 254.7, filed Jul. 27, 2009, and the entire content of both applications is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2010/058686 | Jun 2010 | US |
| Child | 13359779 | US |
