Current Methods The methods used so far of sticking flat elements made of fusible materials into the so-called"sandwiches"have taken advantage of thermoplastic characteristics of the bonded elements, but the actual sticking has been carried out by means of additional fusible components inlaid into the structure of the bonded elements or into the place of sticking. The inlay of fibres or the traditional grounding agent on the reverse side of one of the bonded sides has been used, followed by heating and stressing. When using this method, the sandwich made is always undesirably compacted and compressed. The above current methods also have other disadvantages: the sticking takes place in the form of bonding two infinite belts between pressing rollers, where the final sandwich is subjected to tension, which causes its further deformation; it means that the final product thickness is irregularly affected.
The Principle of the Technical Solution The above drawbacks of the current methods may be removed by utilizing the method of thermoplastic sticking of flat elements according to the invention described below : The principle of the invention is that the sticking does not take place in a limited contact straight line formed by the touching surfaces of adjacent rollers as it happens when sticking is carried out between the rotating rollers of rolling machines (mills), but it takes place over the whole area, without having to subject the bonded sandwich to tension.
The proposed design of thermoplastic sticking of materials gives rise to an opportunity of forming new types of products closely focused on the final characteristics required. In principle, this is the method of melting-on the whole area of the sticking thermoplastic interlayer of the sandwich formed, starting on the reverse side, in an appropriate time and thermal operating mode. Very important is the use of side stops preventing the greater compression of material than required and the impression of the set sticking"interlayer"into the material, which would impair the strength of the bond.
The individual elements of the product (sandwich) are bonded by means of a fusible "interlayer"all over the area. Heat is delivered from the reverse side, and the sticking "interlayer"of a suitable weight is inlaid according to the characteristics of the elements bonded and requirements for the joint strength. The whole technological and operating process is closely connected with time and thermal modes. The input and subsequently output parameters required are attained by side stops of the"press ironer" ; the height setting of the parameters defines the target thickness of the final product.
Another important and also critical moment of the thermoplastic sticking is the subsequent cooling of the bonded joint. This part of the technological node has been resolved by including cooling and calibration equipment especially designed for this purpose.
The whole area of the thermally stuck material is inserted into this piece of equipment, which also has adjustable, built-in side stops. Then the stuck material is cooled by medium (water) passing on both sides.
In comparison with the through thermal sticking (using rotating rollers) where the bonded components (materials) are always partly shifted, the method proposed represents a better solution for fixing the thermal joint.
FxampIPS nf thp Technical Design Implementation The method of thermoplastic sticking of flat elements according to the invention may be clarified in a better way on examples of its implementation.
Example No. 1 Sticking of a carpet mat sized 70 x 50 cm The face consists of a required carpet mat (for example produced by"DILO" technology-"LUX EXTRA"carpet mat). The central, sticking layer is made of the sticking fusible layer, fleece design. This partly melted-down interlayer provides for the joining of the reverse and the face. The reverse side consists of the textile material with a pressed-in anti-slip rubber. Heating is delivered from the reverse side.
The operating temperature of the thermoplastic sticking is 115°C, and the time interval for pressing-in 15-20 seconds. The next step is the technological operation of fixing the joint by cooling and the calibration of the product thickness on the newly developed device.
Example No. 2 Sticking of a self-supporting mat sized 100 x 50 cm The face consists of an unwoven textile mat; its required stiffening is attained by applying the process of stiffening by means of bi-component fibre setting (utilisation of the melting temperature difference of fibres the mat consists of; the face of a mat formed in this way has better utility features than the traditional design where the stiffening of the mat is carried out by impregnation). The central, sticking layer consists of the sticking fusible ph layer, fleece design. This interlayer provides for the joining of the face and the reverse by partial melting. The reverse side comprises a rubber mat of higher weight, which accounts for the self-supporting characteristics of the final product (the rubber mat is made of rubber crumbs by recycling). The operating temperature of the thermoplastic sticking is 140°C, and the time interval for pressing-in 70 seconds. The next step is the technological operation of fixing the joint by cooling and the calibration of the product thickness on the newly developed device.
Industrial Utility The method of thermoplastic sticking of flat elements may be used for sticking self- supporting carpets and mats; there are numerous other ways of its utilisation in household and office interiors, in car industry, shoemaking and health service.