DE2426347A1 - METHOD FOR BONDING TO EACH OTHER SMOOTH SURFACES OF SHEETS, FILMS AND PIPES MADE ON A POLYOLEFINAL RESIN BASE - Google Patents

Description

"Method of gluing together smooth surfaces of sheets produced on a polyolefin resin base ,. Film and pipes. "

Deposits: UAbELMTQ Haoul

in Padua * Italy.

The invention relates to a method for. Bonding of panels Areas of polyolefin resin base and polyolefin resin Leaves produced by derivatives or mixtures thereof, Pilsen and pipes.

In particular, it should be clarified here that the above Sales of derivatives made from polyolefin resins and Mixtures are those who experience the same difficulties when using the inventive bonding process be subjected.

For example, it can be said that the room The most possible substances are fiberglass, asbestos and other substances.

It is known that the polyolefin resins, among which, in particular, the low and high-density polyethylene and polypropylene can be mentioned, cannot be attacked by the commercially available solvents. Such Egg _o enschaft night the above mentioned substances for the manufacture of various pipes well suited. '

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The only disadvantage which affects the development of the said pipes in all sectors is the impossibility of to connect them to each other by means of xQebstoffs. Actually it is known that the collision of the pipes made of such resins is carried out by fusion welding which process is only carried out by leasehold workers v / should be grounded.

IjS is the purpose of the present invention to provide a method • Δχχ. create that makes it possible to make the connection by means of adhesive of smooth planes of bodies made on a polyolefin resin base.

Such bonding by means of glue actually allows in addition to realizing a simple, practical execution, also to obtain an uninterrupted connection of the parts, the stresses occurring are evenly distributed be a good fatigue resistance with attenuation of the ovtl. vibrations occurring here, impermeability, electrical insulation, good resistance to cuts, etc. are guaranteed.

Such a result is achieved by a process consisting of essentially from the following processes:

a) careful cleaning of the planes to be collided;

b) faster warehousing of the surfaces mentioned by oxidizing Flame except for pore opening and simultaneous toning of the

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Opacity;

c) attaching a layer to said flaeclien structural, network-forming fabric that was inserted into the previously penetrates formed pores;

d) Collision of the plans that are in xieruehrung with each other be held until hardening of the ιCIeTastoff occurs.

In order to facilitate the execution of the mentioned collision, especially in the case of drilling, the end of one of the same xtohre is either extended or shaped in such a way that that it was a hat to the end serving as everyone other Hohrs works.

In addition, the sows of the sins of the sins of the susaiame ears are bevelled in such a way that their integration into one another is used (the pipe with external bevels and the nut ears - it inr-oriab3chrae.; En) and the at the ZusaiSFienstoss curtain up: _w ev » ^r orf ciio vx jov.jxcrjoi, c Zlüc-Λυέΐ üarin auf ^ eiioranen iut.

If the hat has been reached by expanding the pipe, it is generally experienced during the heat treatment the gluing process a retreat.

Then it is only connected by a spring tube a hatred necessary to introduce the latter on ^ ev / eitet.

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This means that the groove tube thus assumes the exact shape of the spring tube and therefore precisely on it adheres. If, on the other hand, one of the two pipes to be joined is made directly with the flared end what is commonly referred to as Liuffe, then it will it is preferred that it has an inner diameter 0.1 to 0.5 mm smaller than the outer diameter of the spring tube « The two prescribed measures, i.e. the thermal retraction and the negative interference, allow one to exert continuous external pressure of the groove tube on the spring tube, the penetration of the adhesive into the pores of the to increase areas to be joined together and therefore a To maintain perfect tightness of the collision · Furthermore, the aforementioned negative interference allows including the warming process and the beveling of the ear end a perfect adhesion and a mutual adaptation between the tongue and groove tube, which when Colliding not exactly circular or possibly can have different cross-sections. The surfaces to be connected should be cleaned in this way that will be the removal of all impurities is insured. In practice, it is preferred to degrease or wash with water or with solvents, such as alcohol, to drive through and then the so

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degreased and dried out surfaces with sandpaper rub off *

The cleaned areas are heated for a few seconds on the oxidizing flame of a gas burner, and heating continues until toning the opacity is observed and before such surfaces become glossier

Such treatment brings about an increase in the porosity of the heated surfaces; It is essential that! temperatures of the so treated, not en together areas to be welded 60 ⁰ C frontier. If this is the case, the surfaces will be allowed to cool before starting to coat the adhesive.

Between 40 ° and 50 ⁰ O lying temperatures are practically preferred in that they allow to achieve the best results in terms of surface porosity and therefore a better penetration of the adhesive therein.

Then a layer in the form of a very thin film on base is applied to the two surfaces treated in this way of epoxy, and / or polyurethane, and / or acrylic and / or Applied polyester resins.

Said glue consists of two components, of which one is the accelerator or catalyst and the other is the prepolymer resin, the latter being the base resin

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In practice it is preferred to use fabrics as prepolymer resins or compounds based on isocyanate or cyanoacrylate use.

The two surfaces wetted with the adhesive are brought into direct contact with one another and then pressed on. The adhesive is then left to harden for at least 24 hours before the bonded parts are used. Some examples are described below in order to better explain the idea of the invention and to put it into practice.
example 1

The pipes to be joined are made of high density polyethylene manufactured and both have an outside diameter of 90 mm and a Wandataerke of 3 »5 mm.

The end of a tube, which is subsequently referred to as a "spring", is bevelled to 45 ° on its outer part in order to insert it into a socket arranged on the other pipe to facilitate.

The socket or "groove" has an inside diameter which is the same as the outside diameter of the pipe (90 mm), but which is the same reduced by about 0.3 mm (i.e. from 89j7) to one to allow continuous compression between the two contact surfaces after the spring in the

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<- * 7 -

Lluffe has been introduced.

The end of the groove or sleeve is also beveled on the inside at 45 °, i.e. opposite in the opposite direction the chamfering of the tongue, and this in order to make the groove excessive that ejected during the connection process Absorbs adhesive.

After cleaning inside and outside the area they are rubbed with sandpaper.

Afterwards, the oxidizing flame of a burner fed with propane or other fuel gas is allowed to run on both surfaces for 15-30 seconds until the toning that has occurred, the opacity of the surfaces with the corresponding pore formation is observed.The temperature corresponding to such a change in opacity is between 45 and 50 ⁰ O.

The two surfaces to be joined will be with one previously prepared adhesive coated on isocyanate base, wherein the prepolymer is mixed with its catalyst.

Immediately after the adhesive has been coated, the spring is guided into the groove using, if necessary, levers or hydraulic winches, with the introduction so far is carried out until the tongue is inserted over the entire length of the groove «

To get a good and guaranteed connection,

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it is preferred that the length of the entering the groove Spring is no less than 0.8-1.2 times the diameter of the tube

When there is a connection between the pipe and the pressed connection piece the process to be carried out is still the same * After the connecting piece has been heated by the oxidizing one Flame on the inner surface has no entrance how it can be experienced by the groove of the pipe, which has been obtained by expansion, since it has a greater wall thickness «

Accordingly, the inner diameter of the connecting piece should be 0.1 to 0.5 am smaller than the outside diameter of the pipe to be connected.

Therefore, two elements of the same nominal diameter consisting of a pipe and a connecting piece can be connected without the need for special tools.
Examination attempts

According to the procedures given in Example 1, two pieces of one made from Hochdichtenpolya ethylene Tube that has a diameter of 90 now and a wall thickness of 3.5 mm and a nominal operating pressure of 4 atm (kg / cm.) Have

The ends of the tube obtained in this way are closed with two spherical caps of the same diameter and the same wall thickness,

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and by means of an adhesive according to that described above Procedure attached.

The following experiments were carried out when awake for 24 hours: the whole was subjected to an internal hydraulic pressure of 12 atm »(kg / cm) (i.e. three times the operating pressure) Subjected for over 24 hours without any leakage to be recorded.

The sample part mentioned was then subjected to an explosion test.

The judgment was namely subjected to increasing pressures and at a pressure of 22 atm. the pipe has broken without the collision zone of the two ball caps and which of the pipes have experienced the slightest displacement. The seal quality of the collisions by means of glue two surfaces made of polyethylene was considerably higher than the strength of the xiohrs itself.

Then you have two strips in from the exploded pipe the dimensions of 32 1 50 mm in various places near the collision and both the spring and also cut out the udder tube extensively.

Such two pipe sections are then subjected to dynamometric tensile tests and it has been found that for both parts of the chandelier at a load of 325 ^ g the flow phase des Hohrs is started while the connection is none

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Has IT compliance.
Example 2

In order to further check the capacity of a pipe made of high-density polyethylene to adhere to another tube made of the same material by gluing and the duration of this adhesive force over time, the following experiments were made: three pieces of a tube made of high-density polyethylene with a diameter of 63 mm , a thickness of 3 »6 mm and a pressure rating of 6 atm. have been beveled on one side, completely cleaned with a sandcloth, then the surfaces to be joined were heat-treated under the same conditions described above. Such Flaeehen ¹ were then coated with an adhesive on jPolyurethanharzbase.

Sin with high density polyethylene coated tee with 63 ram in diameter, its inner parts were cleaned with sand cloth and then heat-treated. ITacn coating of the adhesive on the inner surfaces, the three pieces of the Hohr have been connected in one! piece.

Note that the ends of the T-piece have been turned were 0.3 mm smaller than the outer diameter by being on a hatred of the ear (corresponding to 59 »7 mm) brought back were, and they were in the opposite direction to that of the Pipes have been beveled.

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Control attempts

After the glue has set for over 24 hours the acceptance tests were started at a given temperature by letting the pressure vary. With the free ends of the Eohrstueck were then metal connecting pieces Connected who have allowed a hydraulic pressure of 18 atm to be let into the G-eraet to be removed This bridge, which is three times the nominal operating pressure of the pipe used, was maintained for more than 24 hours obtained at room temperature

No sign of leakage was found at the collisions, whereupon the collision was made. Entire unit (consisting of T-piece and pipe pieces) immersed in a water bath, the water of which was warmed up and kept at the constant temperature of SO ⁰ · The pressure was set to 3.6 atm *, corresponding to 0.6 of the nominal operating pressure , reduced and kept constant. Immersion in this water bath at the temperature of 80 * thermostatically controlled took about 200 hours. No signs of yielding or leaks could be found in the collisions until the tests were completed.Afterwards, the pressure within the collided group was reduced to 2.4 atm

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continued uninterrupted. Again, it was a positive one Result achieved. i ... with other words you end up with No signs of the collision ropes and pressure losses were recorded during the attempt.

Kach removal of the collided group from the thermostatic controlled bath has been arranged on the same x to check the explosion test for the maximum pressure. Lan

has the internal pressure of the collided group except for 26 atm. brought c'Faduell at room temperature.

Under such pressure, the pipe ruptured at a point about _a 2 cm from the connection, while the collisions remained unchanged.

From the above one can see the practical use, functionality and advantages of the invention Easily recognize procedure.

2Of course one can somehow, without the principle of discovery to change the details and the execution or realization measures of the process according to the invention vary depending on the requirements set without doing this to leave the scope of protection of the present invention

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Claims (1)

PATENT STRINGING Method for gluing smooth surfaces from on Polyolefin resin base and polyolefin resin derivatives sheets, films and Pipes, characterized in that it essentially consists of the following processes: a) Careful cleaning of those to be joined Areas; b) faster heating of the surfaces mentioned oxidizing fluff except for pore opening and simultaneous Toning opacity; c) applying to said surfaces a layer of structural network-forming adhesive that was incorporated into the previously penetrates formed pores; d) Clash of people who are in contact are held together until the hardening of the adhesive occurs. Method according to claim 1, characterized in that the end of one of the two ears to be joined is widened or designed so that it serves as a hat for the spring end of the other Hohrs. Method according to claim 1, characterized in that 409851/0858 the wider end of the top-hat tube has a diameter 0.1 to 0.5 mm smaller than the outer diameter of the Has spring tube. 4. The method according to claim 1, characterized in that the edges of the ends of the two. to collide Pipes are beveled against each other in the opposite sense, which process in particular be careful is performed. 5. / experienced according to claim 1, characterized in that it _{provides, alternatively, above} the aforementioned chamfering, the execution of an outwardly directed bending process, which is carried out on the top-hat tube in order to facilitate the successive insertion of the spring tube. 6. The method according to claim 1, characterized in that the heat treatment is carried out by an oxidizing flame to lower than 60 °, preferably between 40 ° and 50 ⁰ C included temperatures and over a time between 15 and 30 seconds. Method according to claim 1, characterized in that an adhesive based on epoxy and / or polyurethane and / or acrylic and / or network-forming polyester resin base is used will. 4Q9851 / 0858 - - 15 - 8. The method according to claim 1, characterized in that that as Polyolefinharζ high or low density polyethylene or polypropylene is used. 9 · The method according to claim 1, characterized in that the sheets, films, pipes and other to be glued Bodies are made from polyolefin resins, where they also consist of derivatives of the polyolefin resins mentioned or from mixtures of polyolefin resins and from other substances, such as glass fibers or asbestos can be realized, provided that such the essential properties of the raw material sustained A09851 / 0858