LU81855A1 - METHOD FOR PRODUCING A COMPOSITE PIECE - Google Patents

Description

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- GRAND-DUCHÉ DE LUXEMBOURG

Brevet N ». 0 f ...... ß ...... K ξ du .......... 9.5 ____________ 1 '^ Oyy ^ Monsieur le Ministre ... ÆjSj de l’Économie Nationale et des Classes Moyennes

Titre delivre: ........................................

Service de la Propriété Industrielle LUXEMBOURG

Demande de Brevet d'invention I. Requête ..E.ima .... Carl ..... Er.eudenfee.rg./............6..9J. Q-.SS! E.inhe.im/.B.ex.gstrasseii>: Allemagne Fédérale, représentée par Jean Waxweiler, liï ^ IB ^ AÎÏle Schef fer, "^ LüxeïffiôürgVagïss ^ ........... ..........................

mandataire cinq novembre mil neuf cent soixante dix-neuf déposé ........ ce ................. i ............ .................................................. .................................................. .................................................. .......................... (3) à .......... 15 .., .. 0.0 heures, au Ministère de l'Economie Nationale et des Classes Moyennes, à Luxembourg: '1. la présente requête pour l'obtention d'un brevet d'invention concernant: ................. .................................................. .................................................. .................................................. .................................................. .................................................. ............ (41

Process for producing a composite piece.

déclare, en assumant la responsabilité de cette déclaration, que T (es) inventeurs) est (sont): ............................ .................................................. .....

"Dr ^ Gerhard ..... Gra'ab, Laurent lus s trassë ...... 7, ...... '6800 Manhheïm', '............. ...........................

• 'Allemagne ..... Fédérale ......................................... .................................................. .................................................. .................................................. ............

.................................................. .................................................. .................................................. ...................! .............................. ..............................................

2. la délégation de pouvoir, datée de ........................... le ............. .........................

3. la description en langue -------------------- allemande ....................... . de l'invention en deux exemplaires; 4 ............................ planches de dessin, en deux exemplaires; 5. la quittance des taxes versées au Bureau de l'Enregistrement à Luxembourg, le cinq novembre mil neuf cent soixante dix-neuf revendique pour la susdite demande de brevet la priorité d'une (des) demande (s) de (6). .............. certification ................................... .................. déposée® en (7) ____________ Allemagne ..... Fédérale ................... .....................

le dix février mil neuf cent soixante dix-neuf sous le no. (8) f 29 os 127 ^ 2 ~ iiizzizzzzzzzzzzzi ................ 17 "....... .i7 .....

au nom de ...... company ..... C.ar.L ... Freudenher.g ........................ .................................................. .................................................. ................ (9) élit domicile pour lui (elle) et, si désigné, pour son mandataire, à Luxembourg ............. ..........................

..... Schef f.er .., .. Lu.x.emb.o..urg .......................... ......................................... αοι sollicite la délivrance d'un brevet d 'invention pour l'objet décrit et représenté dans les annexes susmentionnées, - avec ajournement de cette délivrance à .......................... / .. ................. mois.

T mandataire Π. Procès-verbal de Dépôt

La susdite demande de brevet d'invention a été déposée au Ministère de l'Économie Nationale et des Classes Moyennes, Service de la Propriété Industrielle à Luxembourg, en date du: 05.11.1979 15.00 Pr · le ^ inisire à ..... ..heures // £ s ~~ · *. · L’Économie Nationale études Classes Moyennes, t $; sA / yr D C 'b Zt. 5 ^> A 63007 ’yfy _ / /

PBIORITftTS-BEAWSPRUCHUWG

the patent «application in the Federal Republic of Germany

From February 10, 1979 under No.P 29 05 127.2

DESCRIPTION

FOR A PATENT APPLICATION IN

GRAND DUCHY OF LUXEMBOURG

CARL FREUDENBERG

METHOD FOR PRODUCING A COMPOSITE PIECE.

«R Applicant: Carl Freudenberg company, Weinheim / ßergstraße

Process for producing a composite piece

The invention relates to a method for producing a composite workpiece, in which a resin in a mold is sprayed or poured and heated and molded onto a prefabricated second part from an uncrosslinked, elastomeric material to form a first part, thereby strengthening and parallel to that chemical reaction taking place a firm adhesion between the two parts is achieved.

The method mentioned is known from DE-OS 26 16 309. It allows a connection to be established between different types of plastic and a reactive elastomeric material or a resin by spraying the plastic in a molten state directly onto an as yet unreacted zone of the otherwise already cured molding from the reactive material. The resulting heat transfer from the molten plastic to the reactive elastomeric material or the resin _ 9 _ - 2 - completes the chemical reaction already taking place, and the materials adhere to each other after the subsequent cooling and solidification. According to the applicant, the connection achieved is probably essentially based on the activation of adhesive forces.

The method has so far not been able to establish itself in large-scale industrial use, which is most likely due to the fact that the temperature of the tool has to be adapted specifically to each selected material pairing. A clear temperature gradient must prevail inside the tool in order to ensure that the reacting material in the area of the boundary layer with the unreactive material is in a significantly less advanced hardening state than in the other areas. Depending on the size of the manufactured parts, the fulfillment of this requirement often proves to be difficult or not feasible. Probably for this reason, it was previously not possible to use combination workpieces according to DE-OS 26 16 309 with a use that met higher demands.

The object of the invention is to further develop the described method in such a way that it can be introduced into the mass production of small-volume workpieces in a practical manner. The strengths achieved between the two zones of the workpieces obtained should be so great that the breaking point in the event of violent destruction outside the interface runs through one of the two connected partners.

The object is achieved in that a material from the group of acrylic ester copolymers is used as the elastomeric material which contains epoxy groups for crosslinking. According to another embodiment, a substance can be mixed into the elastomeric material and / or the resin, which reacts with the material of the other part during the heating at the boundary layer by means of a polyaddition. The chemical reaction at the boundary layer is therefore identical in both cases.

The targeted creation of a polyaddition between components - V t - 3 - parts of the two substances involved in the connection enables excellent adhesive strengths to be achieved. This result is remarkable insofar as it only requires the mixing in of known substances using known methods or the use of a certain starting material to bring about the required polyaddition reaction. If consumption is greater, some of the required materials in the finished composition can be obtained directly from the manufacturer. The introduction of the method according to the invention into mass production is therefore in most cases not dependent on major investments.

As elastomeric materials, those from the group of acrylonitrile-butadiene copolymers or acrylic ester copolymers can be used particularly advantageously in the process according to the invention. In order to achieve a firm connection to a thermosetting resin, for example an epoxy resin, it has proven to be advantageous if a plasticizer with multifunctional end groups, for example a polyester polyol, is mixed into the elastomeric material. According to another advantageous embodiment, it is provided that a filler, for example a precipitated silica, is mixed into the elastomeric material to bring about the connection with the resin.

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Taking into account the above information, the method according to the invention can be carried out most simply using commercially available molding compounds made from an epoxy resin, which are brought together in a mold with a specially composed mixture of an elastomer compound.

It is basically irrelevant in which form the two materials are introduced into the tool. For example, it is conceivable to inject the two components together in liquid or pliable form into the tool or to inject one component onto a preformed compact from the other component. However, both methods require the use of relatively complex injection molding machines. From an economic point of view - 4 - - 4 - points, it is therefore cheaper to manufacture pre-compacts that have not reacted chemically with the two components, which are layered on top of one another in the mold used and, after the press has been closed, molded together and brought to a chemical reaction. Floor presses can also be used for such a procedure in mass production. It is only necessary to ensure that the tools used have a uniform temperature between 150 and 190 ° C.

The exactly set temperature depends on the rubber compound used. In most cases, the rubber compounds used in the sealing sector can be vulcanized particularly cheaply at a temperature of 180 ° C.

The addition of the substances required in one embodiment of the process according to the invention to bring about the desired polyaddition reaction does not adversely affect the mechanical properties of the elastomeric materials in the amounts required. The required substances can also be selected from a large number of basically usable substances, and this provides a further possibility of avoiding incompatibilities in individual cases.

For example, plasticizers with hydroxyl groups can be used. such as polybutanediols with functional hydroxyl groups, and / or precipitated silicas as fillers and stiffeners in the elastomer compound. It is also possible to use epoxy-containing polymers based on an ethyl or butyl acrylate which are crosslinked by amines:. These can react together with a hardenable molding compound to form a no longer detachable compound without the addition of further reactive compounds. This is completely stable in chemical terms. Even under the influence of substances causing swelling, there is therefore no impairment of the connection. In this regard, the connections achieved according to the invention differ fundamentally from a connection according to DE-OS 26 16 309, which is essentially based on the activation of adhesive forces.

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The method according to the invention can be used particularly advantageously with regard to the production of shaft sealing rings. These usually consist of a stiffening ring made of metal, to which a rubber-elastic part is vulcanized with a sealing lip. Attempts have been made repeatedly to replace the stiffening ring with a plastic part. However, due to the relatively low mechanical strength and also for reasons of price, all attempts in this regard have failed. The method according to the invention promises a solution to this problem.

The curing of the epoxy resins, i.e. H. the transfer to the thermoset plastic is carried out by adding carboxylic anhydrides, carboxylic acids or polyamines (Plastics Handbook Volume XI, Karl Hanser Verlag, Munich, 1971). One can start from low molecular weight, liquid or pasty epoxides. Either higher molecular weight epoxy resins which are solid at room temperature or low molecular weight liquid epoxides which have been converted into the B state with the aid of suitable hardeners are used for the production of molding compounds. Mainly polyamines such as methylenediamine, m-phenylenediamine or also ßortrifluorid complexes of amines are used as hardeners. By adding suitable mineral fillers, such as sand or glass fibers, lubricants to improve processability and release agents for demolding, molding compounds are produced that are available on the market in pre-compounded, giant form.

The elastonizing compositions that can be used can be based on a * natural or synthetic rubber. The required additives can be selected from the group of fillers, plasticizers or other additives, as have been used to achieve other effects in the compounding of elastomer mixtures. When selecting a polyaddition with components of the adjoining, hardening resin layer, it is important that the selected additives have chemically reactive end groups, for example -NHR, -C00H, -SH, -OH, - NH2 or epoxy groups. The three last-mentioned types of chemically reactive end groups have proven to be advantageous with regard to the establishment of a firm connection between the part made of an elastomeric material and that made of a resin.

In most cases, it is not necessary to base the overall strength of the joint on the chemical reaction of a single aggregate contained in only one of the two adjacent parts. Rather, the two adjacent parts are usually composed of a mixture of different substances, and it is therefore a good idea to replace the individually selected additives with those of a comparable mechanical effect, which at the same time result in a polyaddition to the material of the adjacent other part to step. In this way, a highly rigid connection can be achieved without a significant change in the mechanical properties of each of the two parts, which connection cannot be separated by force in the area of the interface.

Example 1 f

A compact made of an uncrosslinked elastomeric material is placed in a heated press mold at a temperature of 180 ° C. The mold is closed and a pre-plasticized epoxy resin compound is injected into the remaining cavity until material emerges at the intended expulsion channel. After a reaction time of 5 minutes, which depends on the mixtures used, the curing of the epoxy resin and the vulcanization of the elastomeric material are completed in parallel to a polyaddition between components of the two materials.

The finished molded part can be removed from the tool. A tear test results in a break outside the interface.

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Example 2

According to the conditions described above, a blank is inserted into the mold, which has the following composition:

Acryl ni tri 1-butadiene copolymer with 28% 100 parts

Precipitated silica 30 parts

Calcined chalk 50 parts

Stearic acid 2 parts ether thioether as plasticizer 10 parts *

Zinc oxide 5 parts

Tetramethylthiuram disulfide 2.5 parts

Benzothiazyl-2-cyclohexylsulfenamide 3 parts

Sulfur 0.7 parts

A second blank made of the molded epoxy resin material is applied to the blank of the specified composition inserted into the tool.

This consists of a high molecular weight resin based on epichlorohydrin and bisphenol A with a polyamine as a hardening component as well as mineral fillers and glass fibers as a reinforcing component. The tool is closed and heated to a temperature of 180 ° C. Due to the pressure exerted on the two blanks, they are firmly pressed together in the region of the boundary layer. In the course of the subsequent reaction of the t

Materials of both parts lead to the formation of a polyaddition in the area of the boundary layer, in which the silanol groups of the precipitated silica and the epoxy groups of the molding material are involved in connection with the amino hardening component. The two materials are firmly bonded to one another in the area of the boundary layer. Even after prolonged storage in a swelling medium, for example in heated oil, the bond obtained cannot be broken by force in the area of the boundary layer.

Example 3

Under the conditions of Example 1, a blank made of an uncrosslinked elastomeric material is used which is based on a butyl acrylate and which contains a crosslinking component which has epoxy groups in the following composition: \ * - 8 -

Elastomer 100 parts

Carbon black with a specific surface area of 80 m2 / g (HAF carbon black) 40 parts

Stearic acid 2 parts

Amine crosslinker 1 part

The molding compound from which the second part is formed becomes corresponding

Example 2 composed.

The processing is carried out according to Example 1. The adhesion between the two materials is so strong after cooling that a break occurs within the crosslinked elastomeric material * in the tear test. The bond at the interface is based on the polyaddition reaction between the epoxy group-containing elastomer and the amine curing component contained in the molding compound.

Example 4

Under the conditions of Example 1, an elastomer mixture of the following composition was used in a corresponding manner for comparison:

Acrylonitrile-butadiene copolymer with 28% AN 100 parts 2

Carbon black with a specific surface area of 40 m / g 70 parts 4

Zinc oxide 5 parts

Stearic acid 2 parts

Plasticizers e.g. B. Dioctyl phthalate 20 parts ► Tetramethylthinram disulfide 2.5 parts

Benzothiazyl-2-cyclohexylsulfenamide 3 parts

Sulfur 0.7 parts

The entire further implementation of the method corresponded to the conditions according to Example 1. Between the two adjacent parts, in the area of the interface, the lack of components which cause polyaddition with components of the opposite material did not give good strength. During the tear test, there was a break in the area of the interface.

λ «- 9 -

Example 5

In a further test, component 1 was produced from an elastomeric composition in accordance with Example 2, with the distinguishing feature that a polyester polyol is mixed in by weight as a plasticizer. The molding compound for the second component corresponded to the specified composition. The adhesive strength under the stated conditions essentially corresponded to the stated result.

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Example 6

Example 2 was repeated with the same composition of the two components with the only distinguishing feature that a polybutadiene with hydroxyl end groups is used instead of the stated plasticizer. The bond strength of the compound, which is based on the polyaddition reaction between the silanol groups of the precipitated silica, the hydroxyl groups of the polybutadiene oil on the one hand and the epoxy groups of the molding material on the other hand, corresponded to that stated.

4th

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Claims (6)

1. A method for producing a composite workpiece, in which a castable or fusible resin in a mold is sprayed onto a prefabricated first part made of an uncrosslinked elastomeric material or poured and heated to form a second part, thereby strengthening and parallel to the chemical reaction taking place, firm adhesion between the two parts is achieved, characterized in that a material from the group of acrylic ester copolymers is used as the elastomeric material, which contains epoxy groups for crosslinking. 2. A method for producing a composite workpiece, in which a castable or fusible resin is sprayed or poured onto a prefabricated first part made of an uncrosslinked elastomeric material in order to form a second part, or is poured and heated, whereby a solidification and parallel a firm adhesion between the two parts is achieved for the chemical reaction taking place, characterized in that a substance is mixed into the elastomeric material and / or the resin, which during heating at the boundary layer by polyaddition with the material of the other component responds. r 3. The method according to claim 2, characterized in that a material from the group of acrylonitrile-butadiene-Co- »polymers or the acrylic ester copolymers is used as the elastomeric material. 4. The method according to claim 2 to 3, characterized in that a plasticizer with polyfunctional end groups is used as the mixed substance of the elastomeric material, preferably a polyester polyol, or a polybutadiene oil with hydroxyl groups. - 11 - T * 1! * * 4 - 11 - 5. The method according to claim 2 to 4, characterized in that a filler is used as a mixed substance of the elastomer, preferably a precipitated silica. 6. The method according to claim 2 to 5, characterized in that an epoxy resin is used as the thermosetting resin, preferably a fiber-reinforced epoxy resin. * 4 4