DE1002996B - Layered sheet material for seals - Google Patents

Description

The invention relates to sheet-like laminate for seals, in particular for such seals, exposed to the action of liquid hydrocarbon fuels commonly found in the Aircraft industry come to use.

There are already containers that are used to hold liquids or for those used Tank fittings or pipes, seals made of elastic natural or reinforced in the middle Plastics known that serve to seal between the metallic parts to be connected.

The properties of the elastic materials to be used are known.

The seals customary up to now generally fulfill their purpose and ensure a permanent one and adequate sealing against the passage of the most abundant fluids from the connection points of containers and the like.

In the development of modern aircraft fuels, however, it has been shown that the previous seals the requirements caused by these fuels no longer meet because the fuel or Fuels have a dissolving and swelling effect on most of the currently known elastomeric substances to have. This is also what these fuels look for in the elastomeric components of the seal to extract the plasticizers used.

The conditions to which such sealants are subjected are made even more difficult by that the containers containing the aircraft fuel are alternately filled and emptied, so that the elastomeric material has a swelling effect first upon wetting and after consumption of the fuel, whereupon the rubbery component dries out, are subject to shrinkage.

If the humidification by the fuel causes an extraordinary swelling, deteriorate the physical properties so far that an effective seal is no longer possible. That same is the case when the extraction of plasticizers or other extractables Excessive shrinkage of the elastomer from the elastomer due to the drying out of the container Caused part of the seal, whereby the required closure is interrupted, so that the fuel seeps out at the sealing points after the container has been refilled.

The object of the invention is to provide a laminate which is suitable as a seal where swelling and extraction occurs by liquid hydrocarbon fuels and which neither swells nor shrinks to such an extent that the sealing effect is affected. The sealing material should also be permanent regardless of the number of changes
for seals

Applicant:

The Goodyear Tire & Rubber Company,
Akron, Ohio (V. St. A.)

Representative: Dipl.-Ing. W. Meissner,

Berlin-Grunewald, Herbertstr. 22
and Dipl.-Ing. H. Tischer, Munich 2, patent attorneys

Claimed priority:
V. St. v. America March 4, 1954

work safely, thanks to the alternating moistening and drying of the liquid container be evoked.

According to the invention, the objects on which the invention is based are achieved in that the layered sheet material for gaskets that counteract the action of liquid hydrocarbon fuels are resistant, at least one layer of a non-stretchable, metallic substance in has a thickness of 0.05 to 0.13 mm, which between layers of an elastomeric material in a Thickness of 0.2 to 0.76 mm is inserted, this elastomeric material being selected from the group which of polymerized 2-chloro-1,3-butadiene and the rubbery copolymers of butadiene and Consists of acrylonitrile.

The invention can be more easily understood with reference to the drawing, in which

Fig. 1 is a cross section of the sheet laminated sheet material according to the invention;

Fig. 2 is a perspective view of a gasket made from the laminated plate material is.

In the drawing, FIG. 1 shows a layer 1 of a non-expandable material which, between layers 2, 2 is inserted from elastomeric material. The layer 1 made of non-expandable material can be metal, Plastic or any material that is dimensionally stable when it is compressive Is subjected to forces exerted on it when the sealing material is in use. Before-

609.836 / 254

3 4

Preferred inextensible fabrics are stainless steel, about 20% and preferably no more than 10% aluminum and brass. Loss of volume after the elastomer The layer 1 made of non-expandable material should be dried for 3 days at 70 ° C. and relatively thin, ie a thickness has been immersed in isooctane for 4 days. range from 0.05 to 0.13 mm to be pliable 5 when the original volume swell in the toluene isose and to allow the seals from the octane mixture exceeds about 200%, ie when punching or cutting out sheet material. the volume more than three times the original-The layers 2.2 of the elastomer !! Material should be thicker in volume, the physical properties of the elastomer component are so disadvantageous than the layer 1 made of inextensible material that a sufficient seal between the irregularly effective seal is not possible. On the other hand, if the volume loss due to extraction, between which the gasket used of extensible fabrics exceeds 20%, becomes moderate surfaces of the rigid metal members. In general, the thickness of the layers 2, 2 shrinkage of the seal after drying out of elastomeric material should be between 0.2 and 0.76 mm so that it does not permit an effective seal. The physical properties of the elastomeric material used in the invention, which polymer of a 2-chloro-1,3-butadiene particularly determine the sufficient effect of the seal, effective elastomer for making the sheet are discussed below. materials from which the seals are made-Fig. 2 shows a seal 3, which are to be made from the one in FIG. 1. Natural rubber and the rubber shown material is made, namely with the zo _ar term copolymers of butadiene and styrene are for non-expandable layer 4, which is not useful between the invention because these rubbers layers 5, 5 is inserted from elastomeric material. An excessive swelling in the toluene-isooctane-The holes 6, 6 located in the seal 3 show a mixture. The rubbery copolymers of possible the application of clamping forces when butadiene and acrylonitrile are also useful for the invention of the seal 3 between the metallic surfaces, especially when it is installed up to the fuel tank (not shown) in equal amounts by weight with natural. Rubber or the rubbery copolymers of

While the ver butadiene and styrene shown in Fig. 1 and 2 are mixed,

bodyings only a layer of non-expandable The implementation of the invention is made easier by

the following examples can be understood, which only as

Layers of inextensible material are present for illustration purposes, but the invention does not refer to it

be, which are intended to restrict between layers of elastomeric material,

are inserted. _ _ Example 1

There are two types of common air ^F

drives used liquid hydrocarbon fuel 35 The substances shown in the following table

fabric which was made from the plate material according to parts by weight on a rubber mill

Invention manufactured seals are exposed. mixed together using the usual methods.

The first fuel type is a mixture of “. . _Ώ .

• · ι jonn / T-1 ij ^ n η / τ ^. j j rubbery polymer one

approximately 30% toluene and 70% isooctane or the _n , - ,,,? " , J, · -tnnn

- .., ^ ... · ,. »1 Jj- ·, τ, i. jx 2-chloro-1,3-butadiene 1UU, O

Equivalent weight, while the second fuel 4 ° - ^ -,. ο rtr \ η

type essentially 100%: isooctane or the equi j. , ^r , c'q

is valentine. It can be assumed that the toluene compo- _Tr , ■. , 'H ■ _in ' _n

. y -o j. χ ,. 1 · -χ ii Calcined Magnesia 1U, U

The element of the first type of fuel was the most elaste calcium silicate 14.0

let mere substances swell extraordinarily. Both the phenylbetanaphthylamine 2.0

Toluene and the isooctane work on it, from the 45 _Mer J _tobenz ^ _thiazol 2.0

compound elastomer those substances ~ 'η "e 12

pull out, which can be pulled out, z. B. liquid piperidinium pentamethylene dithiocarbamate ''.'. 6.1 Plasticizers.

It has now been found that when the leaves were of the above composition

elastomeric component of the layered plate 5 < > in a press for 30 minutes at 149 ° C

materials is selected so that it hardens a maxi. Cut from the hardened leaves

paint volume swell in a first test liquid test specimens were then at for 4 days

and a maximum volume loss, room temperature in a mixture of 30% toluene

after it was subsequently dried and immersed again in and 70% isooctane by weight. To

Isooctane is immersed, a sealing material 55 of this immersion, the test pieces showed a

can be produced which is sufficient for the volume increase of 114.2%. The same cons

functional cycle of the aircraft fuel probes were then in. for 3 days at 70 ° C

container corresponds, d. h, the successive one air dryer set. The test pieces show

and repeated wetting and drying of the th after it has been removed from the dryer,

Container over wide changes with respect to the height 6 ° a volume loss of 4.9%, based on her

and temperature, in which case the layer thicknesses are also the original volume. The same test pieces were made

of poetry are important. then for 4 days at room temperature in isooctane

A physical peculiarity which is used to submerge, after which it increases in volume

Manufacture of a seal for this use as 13.2%, based on its original volume, showed

Significantly discovered is the ability 65 A stainless steel sheet, 0.05 mm thick, was made on

of the elastomeric component, no more than any side with a layer of the in the above formula

approximately 200% and preferably no more than 150% of the material shown coated for a total dimension

to swell when receiving a dew for 4 days of 0.5 mm. After the rubber has hardened

in a mixture of 30% toluene and 70% isooctane to the stainless steel, a seal was made from the

he follows. In addition, the elastomer must not be punched out more than 70 layers. This seal was

Claims (5)

5 6 coated between two metallic surfaces of a test table to obtain a total dimension of 0.64 mm fungsapparates with an inlet. After the rubber had hardened, it was necessary to see the aluminum to put the seal under pressure. A seal was then punched out. The assembled seal was then subjected to the same series of tests Series of tests: Subjected to 5 as carried out in Example 1. There were 1. 7 days of exposure to a mixture of no seepage to any of the he-30 ° / » Toluene and 70% isooctane by weight. imagined experiments observed. 2. 7 days drying in an air oven at Other seals made from rubber-like materials, 70 ° C. Similar to the days shown in Examples 1 and 2 3. Bark for 4 days of exposure to isooctane at io, were prepared and a copolymer of Room temperature. Butadiene and acrylonitrile or mixtures of the co- 4. For 3 days of exposure to isooctane in the case of polymers with up to the same amount by weight 18.3 ° C. ^of natural rubber or the rubbery ones 5. Overnight drying in an oven at 70 ° C. Containing copolymers of butadiene and styrene, After each of the above-mentioned experiments 15 were carried out in the same way as in Example 1 the assembled seal was shown to a print of and 2, prepared and described to the five above Subjected to 2.10 kg / cm ² . In poetry, which was subjected to benevolent tests. There were no the material was constructed, the formula of which observed seepage in the test apparatus if this shown were tested for any of the aforementioned seals under a pressure of 2.1 kg / cm ² No leakage was observed in the last tests. 20 were as long as the used rubber material first does not have a volume swell over 200% when it does Example 2; _ne ; _ne mixture of 30% toluene and 70% isooctane The substances shown in the following table in one parts by weight by weight for 4 days at room temperature were dipped according to the conventional, and secondly, not a volume methods on a rubber mixing plant - has a loss of more than 20% if it is mixed in after the first, Immersion for 3 days at 70 ° C and then dried _π ., ". ,, _c , "mn η ^m isooctane for 4 days at room temperature Butadiene acrylonite copolymer (55:45). 100.0 is _dipped . X. ^m y sq'q Similar tests on seals, önlenru. > ^ ^ _16n rubber parts made of natural rubber or the Plasticizers Zb, V _rubber-like copolymers of butadiene and styrene bteannsaure ^ were produced, resulted in seepage that c 'ΐ ⁰³ ^ i 1 7 ^ after one or more of the five described above bonwetel i, / o tests were observed. Mercaptobenzothiazole disumd /, UU ° Prepared from the above composition Sheets were in a press for 40 minutes at 135 ° C. Claim
hardened. Test pieces made from the hardened Sheets were cut, then for 4 days layered sheet material for against the we- at room temperature in a mixture of 30% toluene 40 kung of liquid hydrocarbon fuels and 70% isooctane by weight immersed. According to resistant seals, thus marked After this immersion, the test samples showed a mark that the same at least one layer Volume increase of 16.3%. The same association of a non-stretchable, metallic material in Search pieces were then for 3 days at 70 ⁰ C in a thickness of 0.05 to 0.13 mm, which an air dryer set. The from the dryer are 45 between layers of an elastomeric material in a remote test pieces showed a sheer volume-inserted thickness of 0.2 to 0.76 mm, being loss of 12.4%, based on the original volume. this elastomeric material is selected from the group The same test pieces were then made from polymerized 2-chloro-1,3-butadiene for 4 days immersed in isooctane at room temperature, after which and the rubbery copolymers of butadiene it has a pure volume loss of 11.1%, based on 50 and acrylonitrile, to their original volume. An aluminum sheet, 0.1 mm thick, was placed on each of the pamphlets under consideration: Single sheet page of the material of U.S. Patent Nos. 2,536,292, 2,240,263 shown above. 1 sheet of drawings © 509 8-6 / 254 2.57