DE2249517B2 - Method for producing a seal on parts to be connected by screwing or plugging together - Google Patents

Description

The invention relates to a method of manufacture a ready-to-use, gas- and liquid-tight seal on parts to be connected by screwing or plugging together, whereby a mixture is produced the base of curable synthetic resins with added lubricant in a layer on the sealing surface and the Layer then hardens completely. In this way, storable prefabricated parts for pipelines such as fittings, pipe parts, armatures, can be produced already received a seal from the manufacturer. This will help the craftsman during the later assembly of the Part of the rather time-consuming sealing of the connection fertilizer removed.

A method of this type is already known for parts of gas-carrying pipelines that are to be screwed together (PR-PS 1231327), whereby as hardenable Synthetic resins and others those based on epoxy are mentioned. However, the information disclosed there is for the Inadequate skilled in the art to produce a seal that meets today's requirements This applies in particular to the area of application with regard to the media to be sealed and one at the proposed raw materials in their final state

residual toxicity

The object of the invention is based on

of the known process steps mentioned

Production of a storable seal on parts

allow that without further preparation on site and Steep gas and liquid tight with each other can be screwed or joined together, being the seal for a variety of media and especially for drinking water pipes

ίο should.

According to the invention, this object is achieved by that the curable synthetic resins are mixtures of at least two of the substances: polyaminoamide compounds, epoxy compounds and phenoplasts used

Individual combinations of substances to be used according to the invention are already known per se, for example from FR-PS 15 06 240 or US-PS 35 63 927. Their suitability as a sealing compound in the form a layer that has cured before the parts are joined has not yet been recognized.

The seals produced by this process prove to be resistant and permanently impervious to cold and hot water, sewage, compressed air, Town gas, natural gas, heating oil, lubricating oil, gasoline, and several solvents. They do not affect the taste and are non-toxic and therefore permissible for drinking water. They are non-corrosive, age-resistant and temperature-resistant from -20 ° to + 135 ° C. The process is In addition, very suitable for economic use by the manufacturer by providing the Preparations do not cause toxic fumes or skin damage, sufficient pot life »5 and rely on the appropriate viscosity for the Let the application of layers on the sealing surfaces cease.

The invention is explained below using exemplary embodiments in connection with -) o Drawing explained in more detail. It shows

F i g. Gas- 1 a view of two by screwing together and fluid-tightly connected parts in the form of a pipe piece end and a (partly shown in section) curved fittings, 4 ^r> 2 shows two tubular plug-in parts prior to their mating, partly in section,

F i g. 3 a coating mandrel with a fitting part, in a purely schematic representation.

F i g. 1 shows, before screwing, a Bogenfit ^r > o ting 1 with an internal thread 3, which carries a solid sealing layer 5 made of synthetic resin and 300 μm, and is practically everywhere the same thickness, the course of the sealing layer largely following the thread surface 3.

The ratio of the layer thickness s to the diameter of the part to be coated will normally be less than 1:20, usually about 1: 100, fco Furthermore, a pipe end 7 with a conical threaded connector 9 which has an external thread II is shown.

These two parts 1 and 7 can be screwed together gas-tight and of course also liquid-tight without the need for an additional sealing operation. The conical threaded connector 9 is screwed into the sealing layer 5 and tightened in the normal manner, as with such

Connections is common.

The elbow fitting 1, on the internal thread 3 the Sealing layer S applied during the manufacture of the fitting can be kept in stock for years lie without the sealing layer 5 undergoes any adverse changes

In Figure 2 is a plug connection (before plugging together) of an outer tube 16 with a solid sealing layer 18 made of synthetic resin and an inner tube 20 with a conical tube end 22 evident. The connection of these two parts 16 and 20, especially at low pressures, for Example wastewater that can be used is carried out in such a way that the conical pipe end 22 is pressed into the outer pipe 16, the sealing layer 18 is deformed and connects the two parts 16 and 20 to one another in a gas- and liquid-tight manner.

The sealant is preferably applied to only one part, as shown, but it is also possible to apply the sealant to the two overlapping parts of the two parts to be joined.

FDr the application of the sealant on a Internal thread is used as a device as shown in FIG. 3 is shown purely schematically

This Fig. 3 shows part of a longitudinal section through a fitting 25, one end of which is provided with a thread 27 indicated Their application is carried out by means of a rotating dome 30, the end of which over part of the Outer surface - it can also be the entire outer surface - carries a thread 33, which corresponds to the fitting thread 27. The mandrel shaft 31 is with a Longitudinal bore 35 provided for feeding the liquid sealant. The bore 35 branches into radial bores 37 through which the sealant can escape.

For coating, move the rotating mandrel 30 in the direction of the arrow into the fitting 25 and leave the mass pour in. The gap between the thread 27 of the fitting and the thread 33 of the The mandrel 30 with the sealing compound 29. By turning back the mandrel 30, the sealing compound, Denoted by 39 in dash-dotted lines, distributed evenly on the fitting thread 25

It is also possible to use the part for a part For example, to provide the inner bore with the sealing coating without a corresponding thread beforehand to cut into this part. When joining, the cuts like a tap External thread provided part of the other part a corresponding thread in the sealing lining. here The synthetic resin covering not only seals, but also mechanically connects the two parts.

In addition to the advantage that, as mentioned, the sealing compound can be applied to the thread or to parts to be plugged together during the fitting production or thread production, and not only during assembly, the connection can be released again if necessary. In most cases, the connection is still tight when screwed again. It is also possible to turn the two parts back against each other, for example by 45 °, without changing the sealing effect. This is important for assembly work. The sealing cover is also secure to the touch and when stored under normal a environmental conditions, for example with fittings lying on top of one another, not menklebend and glued together, not even with other parts, dust particles, dirt, etc. Such connections allow, among other things, a significant time saving compared to the previous ones during assembly and

thus a noticeable reduction in price.

In the following, the method for producing the sealant and the coated parts described on the parts to be joined. It is shown in particular on

ίο what basis the sealant will be obtained.

It should be noted that this sealant is at the parts resulting from the production sticks to the part as a solid coating made of synthetic resin

The requirements of the German Association of Gas and Water Experts are met by the the sealants described below are met in every way

Coverings made from this are used to seal screw connections and to compensate for tolerances Threads and corrosion protection. The hardened outer layers are physiologically awantaVei (for drinking water pipes suitable) solvent-resistant and show a very high adhesive strength on the thread surface and a tack-free, smooth surface.

example 1

To produce the sealant, 160 g of a reactive polyaminoamide (amine number 300) from di- and trimerized fatty acids and polyamine with

140 g of finely ground graphite (particle size <70μπι) Μκ1

160 ml of a mixture of equal parts of toluene and methyl ethyl ketone in a high-speed stirrer intensively mixed

The approach will be followed 140 g of a diglycidyl ether of bisphenol A - viscosity at 25 ° C,

150P, epoxy equivalent 200 - and 5 g of one • * o Thixotropic agent based on silica under

added slowly stirring. The mass is applied to the cylindrical internal thread of 3/4 "fittings made of malleable cast iron with a layer thickness of 150-180 μm and then hardened in a drying tunnel at 120 ° C. for 5 minutes.

The mass is moved at a circumferential speed of up to about 1.5 m / sec (preferably 03-0.6 m / sec) applied along the circumference of the thread and can be optimally processed for up to 36 hours (drip time).

The coating shows no discernible changes in extreme storage conditions such as temperatures of 80 ° C or storage in hot water of 9A ^J C.

When screwing the cylindrical internal thread of the malleable cast iron fitting, which is provided with the sealing lining, with the conical external thread of a Steel pipe, maximum torques of 5-10mkp were measured, i.e. less than normal with hemp seals.

The screw connections were then tested with pressurized water of 25 ° C and 95 ° C and show no leak even up to a pressure of 200 atm

The screw connections can also be used after a long period of time Time of use released without damaging the thread

and if necessary again be tightly connected.

The sealing compound is also suitable for plug connections,

z. B. according to FIG. 2 usable.

Variation ranges for example 1 :

1. Polyaminoamide : epoxy = 1 : 8 to 5: 1

preferably 1: 3 to 3: 1

1.1 Amine number of the polyaminoamide 70 to 450

preferably 85 to 300

\ 2 epoxy equivalent 120 to 1000

preferably 200 to 500

_In dry weight based on the total 03 wt .-%: 2. Minimum amount of thixotropic agent based on silica.

3. Graphite max. 70% by weight, preferably 10 to 40% by weight.

4. Solvent 20 to 70% by weight, preferably 30 to 50% by weight. ,,

Example 2

described, on the degreased cylindrical internal thread of 1 "to T-shaped fittings, so that after drying at 120 ⁰ C a layer thickness of 260-270. Subsequently μ reaches the sealing gasket at 210 ° C is cured during 20 min.

The parts prepared in this way can also be stored for a long time before use, ie until the tight connection is established, without the hardened sealing compound changing or showing undesirable effects.

It is easy to screw in conical external threads; maximum torques of 7 - 9 mkp are measured.

The screw connections were found to be completely tight in pressure tests with water and heating oil at temperatures of up to 100 ^° C. and pressures of up to 200 atmospheres. The screw connections could even after a year

Polyaminoamids (amine number 90) from dimerized and trimerized fatty acids and polyamine dissolved in equal parts of xylene and butanol at 60 ^° C. and introduced 20 g of a pulverulent phenol resol. 100 g of finely divided graphite and 2 g of thixotropic agent are then added to the batch at 25.degree. C. with stirring.

The sealant is applied to the defatted cylindrical internal thread of 1 "T-fittings analogously to Example 1 is applied so that after drying a layer thickness of 150 - is μΐη reached 200, then the gasket covering at 200 ⁰ C during 30 is cured min.

It is easy to screw in conical external threads; there are maximum torques measured from 7-9 mkp.

In pressure tests with water and heating oil at temperatures up to 100 ^° C. and pressures up to 200 atü, the screw connections were found to be completely tight.

The screw connections can also be used after 10 days of storage at 80 ° C without damaging the fitting be solved again.

The mass is physiologically harmless, solvent-resistant, prepared when applied to the parts no difficulties even with longer pot life and serves as a seal for screw connections as well as the thread tolerance compensation and corrosion protection.

The mass can easily be stored for 6 months.

Variation ranges for example 2:

1. Polyaminoamide: phenolic resol 2: 1 to 10: 1
preferably 3: 1 to 6: 1
Amine number of the polyaminoamide 70 to 450
preferably 85 to 300

2. Graphite maximum

75% by weight
preferably 25 to 50 wt ⁰ /

2Ii

50

55

Example 3

600 g of a diglycidyl ether of bisphenol A (melting point 72 ° C., epoxy equivalent 580) were dissolved in

140 ml of methyl isobutyl ketone and 70 ml of xylene.
To this end, a solution of

380 g of a novolak (melting point 75 ° C.) and 20 g

Hexamethylenetetramine in 400 ml of ethanol.
240 g of finely ground graphite and 60 ml of ethyl

glycol added
The sealing compound is worn as in Example 1 at 80 ° C. and can be removed again without damaging the fitting.

Example 4

700 g of a diglycidyl ether of bisphenol A (melting point 60 ⁰ C, epoxy equivalent 500) were in a mixture of

200 ml of methyl isobutyl ketone and

100 λ .2 xylene dissolved and

450 g of phenol resol (55% in butanol) were added.
The approach were

280 g of finely ground graphite together with

10 g of 55% phosphoric acid in 50 ml of butanol were added.

The order of the sealant to the threads and the drying were carried out as described in Example. 1 The sealing lining was ^{tempered at 190 °} C. for 15 minutes for curing. During pressure tests, as described in Example 2, all screw connections remained tight.

The above-described sealing compound is applied to parts that are to be connected in a gas- and liquid-tight manner by screwing or plugging together by applying the liquid sealing compound to one or both parts and spreading it with a doctor blade to form a coating of at least approximately the same thickness everywhere. This covering is then cured, whereupon it can be stored practically for an unlimited period of time without any noticeable change, as stated. It is possible to insert the sealant into the doctor blade and guide it through bores on its outer surface, so that the application of the sealant and its spreading takes place immediately one after the other and in a coordinated manner which at least partially has a threaded outer surface, the thread having to correspond to that of the fitting or pipe, since the thread of the workpiece should be reproduced as precisely as possible by the compound. Instead of the dome, a disc can be used accordingly. As already explained in the examples, the sealing compound is hardened after the workpiece has been coated

With such a method, the application speed along the circumference of the thread is up to Sol IJS m / sec, preferably 03 to 0.6 m / sec, measured in the circumferential direction of the fitting or pipe.

1 sheet of drawings

Claims (5)

Patent claims: 1. Process for the production of a ready-to-use, gas- and liquid-tight seal on through Screwing or plugging together to form parts to be connected, whereby one mixes on the base curable synthetic resins with added lubricant in one layer on the sealing surface and the Layer then cures completely, characterized in that the curable synthetic resins are mixtures of at least two of the Substances: polyaminoamide compounds, epoxy compounds and phenoplasts used Z Process according to Claim 1, characterized in that polyaminoamide compounds with an amine number of 70 to 450, preferably between 85 and 300, and epoxy compounds with an epoxy equivalent of 120 to 1000, preferably between 200 and 500 in a mixing ratio of i; S to 5: 1. preferably between 1: 3 and3:!, used 3. The method according to claim 1, characterized in that the polyaminoamide is a condensation product of dimerized and trimerized fatty acids and polyamine, a diglycidyl ether of bisphenol A as an epoxy compound and a solvent Mixture of aromatics and ketones used 4. The method according to claim 1, characterized in that one polyaminoamide compounds with an amine number of 70 to 450, preferably between 85 and 300, and phenoplasts from Phenolic resole and / or kovolak type, if appropriate with a formaldehyde dispenser such as hexamethylenetetramine, in a mixing ratio of 2: 1 to 10: 1, preferably between 3: 1 and 6: 1, is used 5. The method according to any one of claims 1 to 4, characterized in that the mixture curable synthetic resins, admixed with a thixotropic agent, for example based on silica.