CS239055B1 - A method for welding formations from polymeric materials and a welding gun to perform this method - Google Patents

Abstract

The purpose of the solution is to increase the strength of the joint in welded polymer materials. In these materials, mainly in insulating type flooring with textile underlays, an electrostatic charge is partially introduced into the surface during production, which is further amplified during subsequent manipulations and has a negative effect on the strength values of the joint (weld). This deficiency is eliminated by the fact that during the welding process, the electrostatic charge is continuously removed from the immediate vicinity of the weld seam. The method is performed using a welding gun equipped with a pressure bar (2) for continuous contact with the surroundings of the joint, attached to a hot air nozzle (5). The pressure bar (2) is made of an electrically conductive material and conductively connected to the neutral conductor.

Description

The invention relates to a method of welding polymeric material formations, in particular to fusion welding of sheet multilayer formations, such as plastic flooring, in particular of an insulating type. The invention further relates to a welding gun for carrying out this method.

The vast majority of plastic flooring produced so far is laid by gluing and welding. Before the actual laying, the flooring must be cut into billets, which are always larger than the room dimensions.

After this necessary stabilization time, the floor covering is bonded with solvent or dispersion adhesives either to the stop or to the gap - usually 2 mm. After laying the floor covering to the stop, the welding gap is milled out when laying on the milling gap. The plasticized PVC welding cord is then introduced into the gap by means of a welding gun which guides the cord, gradually melts and stores it. The optimal welding temperature is 600 ° C, speed 100-120 cm / min. For smaller rooms a manual welding method is used, in larger rooms a semi-automatic or automatic welding method is used.

The disadvantage of the existing welding method is especially in the case of insulating type flooring with textile pads that the surface electrostatic charge, which was partially clogged into the surface by manufacture and is further amplified during further manipulations, has a negative effect on the strength of the joint (weld). treads with each other.

The above-mentioned drawback removes the welding method according to the invention, which is based on the fact that it is in the process

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238 OSS continuously dissipates electrostatic charge from the immediate vicinity of the joint

The essence of the welding gun for carrying out the method according to the invention is that its hot-air nozzle is fitted with a pressure bar for continuous contact with the surrounding area of the resulting joint, made of electrically conductive material and conductively connected to the neutral conductor.

The main advantage of the method according to the invention and of the apparatus for carrying out it is a substantial increase in the strength of the joint. For example, insulating flooring where the strength increase is most pronounced is an increase of up to 190% of the original value of bond strength, on average 150% of the original bond strength.

In order to illustrate the invention in greater detail, the following examples illustrate a particular embodiment of the invention when welding insulating polyvinyl chloride floor coverings.

Example 1

Insulating flooring with textile backing had the following construction:

- upper part consisting of wear layer + middle filled layer total thickness 0,9 mm

- laminating layer 0.4 mm thick

- Textile pad thickness 3.5 mm

Both the top and the laminate were made of polyvinyl chloride mixtures commonly used for these purposes. The flooring was cut into billets and left for 48 hours before bonding at a temperature of t = 25 + 2 ° C and a relative humidity of 55-65% for shape alignment. After gluing, welding was carried out with a welding cord of softened polyvinyl chloride. The 4 m-diameter cord was gradually melted with a welding gun and placed in a 2 mm gap.

Welding was carried out first by the classical method, then under otherwise identical conditions by the method of the invention. Evaluation

- 3,239,035 strength of the obtained joints was made according to ČSN 64 7012.

The following results were achieved:

- classical 71,6 N / cm

- by the method according to the invention 81.3 N / cm - increase by 13.5%

Example 2

Insulating flooring with textile backing had the following construction:

- upper part folded as in example 1, thickness 0,6 mm

- laminating layer of common composition 0,4 mm

- textile pad 3,3 mm

After cutting into the blanks, the flooring was left for 48 hours at a temperature of t = 25 + 2 ° C and a relative humidity of 60-65% for shape alignment. After gluing, welding was carried out as in Example 1. The results obtained are as follows:

- in a conventional manner 54 N / cm

- by the method according to the invention 103 N / cm - an increase of 90.8%

An example of the construction of a welding gun for carrying out the method according to the invention is shown in the attached drawing. The welding gun, consisting of a feeder welding rod j> associated with the hot air nozzle 2 t connected to the chamber with a heating element connected via insulating intermediate tray 2 ^{with the} chamber for the fan 6 connected to a handle 2 containing the control system and the input supply elektrošňůry 8 is still used by the device of conventional construction . According to the invention, the gun is provided with a pressure bar 2 of electrically conductive material, conductively connected to the neutral conductor. The connection is made from the pressure bar 2 on the surface by points A, B, then passes into the device and goes through the fan chamber 6 - points C, D - and the handle 2 with the power cord 8 to the point E.

- 4,239,055

The pressure bar 2 is mounted on the hot-air nozzle J and points towards the material to be welded, that is to say downwards. It is designed in such a way that, in addition to the continuous discharge of electrostatic charge from the vicinity of the site of the emerging joint, it simultaneously compresses the materials to be welded and thus mechanically assists the formation of a quality joint.

Claims (2)

OBJECT OF THE INVENTION 239 055 A method of welding polymeric material formations, in particular fusion welding of sheet multilayer formations, such as plastic flooring, in particular of insulating type, characterized in that, during the welding process, an electrostatic charge is continuously removed from the immediate vicinity of the weld spot. 2. A welding gun for carrying out the method according to claim 1, formed by conventional components, in particular a welding wire feeder connected to a hot-air nozzle connected to a heater chamber, connected via an insulating lining with a fan chamber ₍ connected to a handle containing the control system and the cord entry) characterized in that a pressure bar (2) for continuous contact with the surrounding area of the joint being formed, made of an electrically conductive material and conductively connected to the neutral conductor, is mounted on the hot-air nozzle (3).