WO2006005322A1 - Polymer seal - Google Patents

Abstract

The invention relates to a method for the production of a seal comprising bound hard and soft polymer material. The invention is characterised in that the polymer starting materials for hard and soft polymer material are poured into each other and are simultaneously brought together for hardening.

Description

Title: Polymer seal

description

The present invention relates to the Oberbegrifflieh Bean¬ spruchte and thus deals with the production of Dich¬ obligations.

Seals are used in the connection of objects to prevent leakage of fluid flowing between them at the «transition point. This is required in a large number of very different applications, for example in the sealing of window handles on window profiles against rain and wind, in oil filters in internal combustion engines, bearing arrangements for lubricated bearings of machines, etc.

Typically, the seal is made by pressing an elastic material against a hard surface, the elasticity of the soft material making possible a close contact with the hard material, avoiding or at least reducing the passage of fluid due to the flat, close fit , The soft material may be formed approximately in the form of sealing rings such as O-rings, etc., but it has also been proposed to provide one-piece Verbindun¬ gene of soft material on the one hand for the actual sealing surface area and hard material on the other hand for the Un¬ support thereof. In particular, a so-called duo method was proposed and published by the present applicant, cf. Special print from "Kunststoffe" 11/93, in which a hard-soft combination for a filter end disk, made from a 2-component PUR system in Duo Procedure, is shown. This duo method provides for the combination of two casting operations in which z. B. a hard Filterendscheibe with cast foam seal is obtained. Among other things, the article cited here shows a flagship cartridge for the automobile industry. In the automotive sector, particularly stringent requirements are met because it is increasingly necessary to pay attention to the use of ecologically compatible materials, low weight and high durability at low costs. This applies to all areas in the automobile, even for such as oil filters of internal combustion engines, which must endure such temperatures in chemically aggressive environment, and on the other hand, even a partial sealing failure has fatal consequences.

It is desirable to provide a sealing capability in which at least some of the requirements are at least partially met.

The object of the present invention is to provide new products for commercial use.

The solution to this problem is claimed in independent form. Preferred embodiments can be found in the subclaims.

The present invention thus proposes in a first

The idea of the invention is a process for the production of a seal with bonded hard and soft polymer material, in which it is provided that the polymer starting materials for hard and soft polymer material are poured into one another and simultaneously cured with one another. A basic idea of the invention therefore consists in the knowledge that a seal is considerably cheaper and more durable to manufacture if casting or injection of the polymer starting materials into one another takes place in such a way that simultaneous curing of the polymer starting materials is made possible. Simultaneous curing not only simplifies machine assembly compared to a situation in which first a previously cast piece of material, such as a soft seal, is applied and then encapsulated in a second step, but advantages over a situation are also achieved in which first a material is poured in, a predetermined time of hardening is awaited and then the remaining polymer material is poured on. According to the present invention, not only is the process simplified compared to successive production of the hard and soft cast polymer regions, but also the bond between the hard and soft materials is more intimate. This is particularly advantageous in seals that are loaded, be it by mechanical stress, such as may be caused by vibrations, thermal and / or chemical stresses, such as may occur in seals against hot fluids, or be it by frequent frictional stress or similar.

The present method thus provides not only a procedural simplification, but at the same time a product improvement.

A particularly significant product improvement can be obtained in a preferred variant by adding for the outer

Part of a preferably ring-shaped or disc-shaped seal a harder and / or more closely cross-linked or when manufactured wetting polymer material with a volume change that is lower in hot engine oil is used, while for the disk area along the inner diameter a softer and / or more elastic and / or coarsely meshed polymer material crosslinking during production and casting with a greater volume change in hot engine oil ¬ is selected.

The invention in this preferred embodiment advantageously makes use of the recognition that polymer materials after storage in hot engine oil change their volume and swell or shrink. The proposed embodiment is preferred because, in the case of ring-shaped or disc-shaped objects made of such polymer materials, the change in volume takes place mainly one-dimensionally, that is to say essentially by a change in diameter, either as an increase in diameter or as a reduction in diameter. The proposed, preferred material choices now have the effect that the volume change, which is preferred primarily in the slice plane, is restricted or prevented by suitable measures, and thus the change in volume takes place in the remaining remaining directions. By now the materials of the disc interact suitably, in particular, as proposed, hard in the region of the outside diameter, with a smaller volume change and soft in the region of the inside diameter, with a larger change in volume, or with oppositely matched opposing / In spite of slight changes in the outer diameter of the disc, the inner diameter can be kept almost constant, thus ensuring a seal along the inner diameter of all discounts. conditions are particularly well ensured. The proposed choice of material thus leads to improved filters.

Another advantage of this combination of materials, which is hard in the area of the outside diameter and softer and / or more elastic in the region of the inside diameter, is that the soft-elastic inner ring has mounting forces when the oil filter is placed on a specially provided plastic mandrel in the Motor housing can be kept low, but still a certain bias or a sufficient pressure is given by which a good sealing function can be guaranteed under all conditions, especially at from room temperature to temperatures hot engine oil rising ambient conditions.

Preferably, a passage opening in the soft polymer is left already during casting, so that it is not subsequently work into it. Due to the simultaneous casting, the area in which soft polymer is provided around the passage opening can flow smoothly into those in which hard

Polymer is to be arranged. This has the advantage that, despite the formation of the passage opening through soft polymer, a stable arrangement with high strength and at the same time excellent sealing effect is nevertheless obtained.

It is possible to form the seal plate-shaped and to form a projecting into the seal opening sealing bead of soft polymer. This can be done during casting and thus provides in particular a radial seal.

It is possible not to cast the gasket as such in isolation, but to seal it off directly during casting. border object or a sealed surface thereof. In particular, it is possible to provide a casting to an end face of a filter cartridge, such as an automotive oil filter or the like. Here, it has an advantageous effect that the flowable material is slightly drawn into the filter by the capillary forces, which mechanically further stabilizes the latter on the front side with only a small amount of material, without significant impairments arising from the simultaneous casting. This applies in particular when a cylindrical filter body is provided with a front-end seal and the passage opening to be sealed with the soft polymer material lies in the clear passage of the cylinder. This is because the stabilization of the filter cartridge typically takes place in the outer region and accordingly with hard polymer material, which is particularly advantageous and desirable because the overall arrangement is thus mechanically more stable. It is possible to design filter cartridges in such a way that no additional cage made of plastic is provided around the filter cloth or fabric, provided that it also has oil-impregnated properties or does not retain its required stability, since the front-end castings are cast-on Polymer materials do not impair this stability, but rather increase it.

It is possible to use polyurethanes as polymer starting materials. These can be made sufficiently fluid resistant to a variety of technically relevant fluids such as hot engine oils and the like. In particular, it is preferred to use two-component polyurethanes. In such a case, for each polymer starting material, so so¬ well for the polymer starting mass of both hard and soft polymer feedstock ^'different poly- Urethane compositions, in particular different two-component polyurethane compositions can be used. In any case, it is preferred to use for the hard and the white polymer starting material those which combine intimately with one another, be it by the formation of a quasi-purely mechanical crosslinking of the respective polymeric substances, be it by the formation of chemical reacted polymer starting materials. It is particularly preferred to use non-foaming polyurethanes, in particular for the soft polymer starting material, since these generally prove to be significantly more stable, as far as swelling behavior in aggressive and / or hot fluids, mechanical abrasion, vibration sensitivity, etc. is concerned.

Protection is also claimed for the most preferred

Polymer starting materials. It has been found that while the invention can be carried out with a series of polymer starting materials, particularly good results are obtained if either the polymer starting materials are not more than 90%, preferably not more than 60%, in particular which have no more than 40% different times until an initial rigidity permitting object manipulation is obtained, the hard and soft polymer materials have linear heat output coefficients which do not differ by more than 70%, in particular not more than 25%, and / or if the elasticity ratio differs at least by 20%.

Alternatively and / or additionally, it may be preferred for the hard polymer materials in hot engine oil to undergo volume changes of between -3 to +3% and for the soft polymer materials to be those of between -15 to +15% and / or the difference in hardness between them is at least 15 ShoreA and / or 15 ShoreD.

Extremely different times until initial strength is achieved prevent a very intimate bond, whereas mismatched polymer materials, in particular polymer materials which are mismatched with respect to their volume change in hot engine oil, lead to an inadequate seal in the filter which also applies to different thermal expansion coefficients, which can lead to a temperature cycle-induced interface failure.

On the other hand, a too close elasticity ratio shows hardly any advantages in use. It should be mentioned that as polymer starting material for the purposes of the invention with the desired, at least partially, but preferably cumulatively present properties, two-component polyurethane casting compositions are advantageous, especially starting components which are liquid at room temperature.

Furthermore, protection is claimed for an article with a seal, which is formed from two different hard polymer materials and is cast on an object simultaneously. The article may preferably be an oil filter and it is possible to form the passage opening with a radially vorgese¬ Henen seal. Protection is therefore particularly claimed for an oil filter with inventive seal bean¬.

The invention will now be described by way of example only with reference to the drawings. In this one is shown in Fig. 1: an oil filter of the present invention.

According to FIG. 1, a counterpart 1, generally designated 1, comprises a seal 2 made of polymer material, which is formed from two differently compliant polymer materials 2a, 2b and is cast onto the object on a surface 3.

In the present case, the article 1 is an oil filter for this conventional hot oil-resistant nonwoven with a folded structure, as indicated by ribs 3a, 3b, 3c, etc. As can be seen in Fig. 1a, the outer periphery 4 of the oil filter, which is viewed from above in Fig. 1a, is generally circular while internally leaving a generally circular area 5 from the filter ribs. As is generally customary, a filtering of hot engine oil takes place when it passes through the filter ribs, which can take place from outside to inside. The areas to be filtered and already filtered are separated on the one hand by the filter ribs and on the other hand by the seal 2 to be described here.

The sealing plate 2 is cast on the end face of the oil filter. It has soft polymer material 2b in the region of the clear opening 5 of the oil filter, which here has a bead 2bl which protrudes radially inward and has flowed into hard polymer material 2a, as shown by the indicated transition line 2c, but with explicit reference thereto ¬ it should be noted that this bead is not absolutely necessary. The polymer material is also drawn capillary into the edge region of the end faces of the filter bags 3a, 3b, 3c, etc. and cured there. The seal opening is designed for this purpose to be placed in use on a sealing mandrel made of hard Kunst¬ material, metal or the like.

The arrangement is produced as follows: First, a casting mold is provided above which casting nozzles are arranged for non-foaming 2K PU polymer mass starting material, specifically two-component mixtures produced in a peripheral area of nozzles for a hard-setting non-foaming polymer material and near a central opening area Nozzle for softening, non-foaming polymer starting material. Now, material is poured into the mold pan in sufficient quantity and the end face of a prepared object, such as an oil filter-forming folded ge filter web, placed. Optionally, a homogenization of the polymer starting material cast into the mold can be achieved by rotating the mold or by providing a plurality of inlet nozzles.

Now the polymer masses cure simultaneously with each other. There is also a curing and thus stabilization of drawn into the filter fabric polymer starting material instead. The polymer compositions of the hard and soft polymer starting materials are at the same time intimately bonded.

After obtaining an initial strength of both soft and harder polymeric material, the filter can be turned and the other end side can be similarly provided with a seal. It should be noted that it is not mandatory to provide both sides in the same way with a sealing region according to the invention, wenn¬ same is advantageous. It should be mentioned that in addition to the oil filter described above, other seal arrangements can be produced in the manner described.

It should also be mentioned that it may be advantageous to add one or more components and / or constituents to the polymer masses or at least one of the polymer compositions which are cast in one another, at least partially, but possibly also during storage in hot engine oil can be completely dissolved out so as to specifically influence a difference in the swelling behavior or in the volume changes of the hard polymer masses on the one hand and the soft elastic polymer masses on the other hand and / or a negative swelling behavior or a volume reduction during and / or after specifically to cause storage in hot engine oil.

It should also be pointed out that it is possible to increase the dimensional stability and / or to limit changes in volume, particularly during storage in hot engine oil, in the flat, in particular disk-shaped inserts, in particular of oil-resistant felts, felts with fabric inserts , Vlie¬ sen, tissues and / or filter papers are used, which, if desired, may also be pre-cured and which inserted during manufacture, for example, in the mold integrated in the subsequent casting process in the polymer mass wer¬ or enter into this inseparable connection , whereby the sealing plate produced in the casting process is also mechanically reinforced and / or reinforced.

- II -

Claims

claims 1. A process for producing a seal with connected hard and soft polymer material, characterized gekennzeich¬ net, that the polymer starting materials for hard and wei¬ Chen polymer material are poured into each other and are si¬ multan each other to harden. 2. Method according to the preceding claim, characterized ge indicates that during casting a passage opening is left. 3. The method according to any one of the preceding claims, character- ized in that a sealing plate is formed, in which in particular soft polymer material is provided adjacent to a sealing opening, in particular a sealing bead of soft polymer material, which projects into a sealing opening. 4. The method according to any one of the preceding claims, da¬ characterized in that the polymer starting material is angegos¬ sen at a sealed portion of an article. 5. The method according to any one of the preceding claims, da¬ characterized in that polyurethane is used as polymer starting material Po¬. 6. The method according to the preceding claim, characterized ge indicates that two-component polyurethane is used as mer¬ merausgangsmasse, in particular respectively different two-component mixtures for the polymer starting material of the soft and hard polymer respectively. 7. The method according to any one of the preceding claims, da¬ characterized in that non-foaming polyurethane is used, in particular non-foaming Ausgangs¬ mass (s) for the soft polymer starting material. 8. Polymer starting material for carrying out a method according to any one of the preceding claims, characterized gekenn¬ characterized in that the curing times of Polymerausgangsmas¬ sen differ by not more than 90%, preferably not more than 40 'to achieve an initial strength and / or the thermal expansion coefficient of hardened polymer compositions differ by no more than 70% and / or the elasticity ratio of the soft and har¬ th polymer materials differ by at least 20%.