1. Field of the Invention
The present invention relates to a pretreatment method and system for application of coating to shoe parts, and more particularly to a pretreatment method and system for application of coating to shoe parts, which are capable of replacing the conventional primer coating process with the UV radiation process.
2. Description of the Prior Art
Pretreatment primer for rubber has found wide application due to the fact that the delamination agent on the rubber surface is very hard to remove on the rubber surface and will cause a very bad bonding to Rubber and other materials. Also due to the physical restriction of the chemical mixing, it's very hard to use water based solvent to replace this kind of primer. However, if using solvent based primer might cause healthy problem to worker and not good for earth sustentation.
The conventional application of adhesive coating pretreatment to shoe parts, as shown in
If the shoe parts are made of rubber, as shown in
It is obvious from the above description that UV radiation has found wide application in shoe industry. It is to be noted that, unlike the conventional application of adhesive coating to the shoe parts simply by washing the shoe parts before UV radiation or directly by UV radiation, the shoe parts made of rubber or TPU must be subjected to etching or grafting process with specialty chemicals to improve adhesion. Therefore, a large number of pretreatment processes are inevitable, which will produce volatile chemicals which are harmful to environment and human beings.
Furthermore, the conventional application of adhesive coating pretreatment to shoe parts still involves manual labor, and therefore is low efficiency.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.
The primary objective of the present invention is to provide a pretreatment method for application of coating to shoe parts, which is capable of replacing the conventional primer coating process with the UV radiation process. The coating pretreatment to the shoe parts can be carried out continuously in an automatic manner. Besides, creating etching effect by using UV-C radiation and ozone activating can truly improve the bonding of the shoe parts to the adhesives, without substantial increase in equipment cost.
To achieve the above objective, a pretreatment method for application of coating to shoe parts in accordance with the present invention is carried out between a punching process and a coating process, and comprises the following steps: preparing a shoe part; transporting the shoe part with a transport means to a first chamber in which being disposed with UV lights, subjecting a surface of the shoe part to ozone activating and etching by radiating it with UV-C rays; transporting the shoe part with the transport means to a second chamber in which being disposed a cleaning device, removing micro substances from the surface of the shoe part by cleaning it with the cleaning device; transporting the shoe part with the transport means to a third chamber which is functionally the same as the first chamber, subjecting the surface of the shoe part to ozone activating and etching by radiating it with UV-C rays again; and selectively transporting the shoe part with the transport means to a fourth chamber which is functionally the same as the second chamber, and cleaning it for the second time.
Another objective of the present invention is to provide a pretreatment system for application of coating to shoe parts, wherein the UV radiation system of the present invention can be provided with more reaction chambers for UV-C radiation and cleaning, so as to increase the breadth of application of the UV radiation system. Subjecting the surface of the shoe parts to UV-C radiation and cleaning process more than one time can activate the surface, and improve the follow-up coating quality.
To achieve the above objective, an UV radiation system applied to do coating pretreatment to the rubber-made shoe parts by using the pretreatment method in accordance with the present invention comprises: the transport means for transporting the shoe parts; the first chamber provided on the transport means, in the first chamber being provided UV lights for producing 30-80 ppm ozone by radiating the shoe parts with UV-C rays, at a top of the first chamber being defined a vent for discharging ozone; the second chamber being connected to the first chamber, and in the second chamber being disposed a cleaning device and cleaning liquid; the third chamber being located behind and connected to the second chamber, in the third chamber being provided UV lights for producing 30-80 ppm ozone by radiating the shoe parts with UV-C rays, at a top of the third chamber being defined a vent for discharging ozone; the shoe part being transported by the transport means, subjecting the surface of the shoe part to ozone activating and etching by radiating it with UV-C rays in the first chamber, removing micro substances from the surface of the shoe part by cleaning it with the cleaning device in the second chamber, and subjecting the surface of the shoe part to ozone activating and etching by radiating it with UV-C rays again in the third chamber.
The present invention will be clearer from the following description when viewed together with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment in accordance with the present invention.
Referring to
As shown in
Referring then to
In the first chamber 1 are provided UV lights 8 for radiating the shoe parts 6 by UV-C rays at energy density of 2.0-5.0 J/cm, so as to produce 30-80 ppm ozone. On the top of the first chamber 1 is defined a vent 9 for safely discharging ozone. In this embodiment, the UV lights 8 are lamp tubes, preferably 10-46 lamp tubes, and the UV lights can also take other forms.
The second chamber 2 is connected to the first chamber, and in the second chamber 2 is disposed a cleaning device, which is an ultrasonic cleaner in this embodiment, and provides ultrasonic waves to a cleaning liquid 7 stored in the second chamber. Shoe parts 6 are then immersed in the cleaning liquid 7 to wash micro substances off the surface of the shoe parts 6, such as silicon oil. The cleaning device can also be Ion fan or atmospheric plasma cleaning machine. At the exit of the second chamber 2 is provided a drying apparatus, which comprises an air knife (not shown) for producing narrow and strong air flow, and a plurality of NIR (near-infrared) heating lamps (not shown), so that most part of the cleaning liquid residues can be removed from the shoe parts 6.
The third chamber 3 is located behind and connected to the second chamber 2 and structurally and functionally the same as the first chamber. In the third chamber 3 are disposed UV lights 11 for emitting UV-C lights, and at the top of the third chamber 3 is defined an exit 12 for discharging ozone. Setting up the third chamber 3 is aimed at activating again the surface of the shoe parts 6 for a better reaction, so as to improve the follow-up coating quality.
The fourth chamber 4 is functionally and structurally the same as the second chamber 2, and can be selectively connected to the third chamber 3. In the fourth chamber 4 are stored cleaning liquid 13 and an ultrasonic cleaning device which are used to remove micro substances from the surface of the shoe parts 6. In this embodiment, the cleaning liquid 13 in the fourth chamber 4 and the cleaning liquid 7 in the second chamber 2 have the same chemical composition. Or, the cleaning liquid 13 in the fourth chamber 4 may have different chemical composition with respect to the cleaning liquid 7 in the second chamber 2 based on the material property of the shoe parts 6. More specifically, the cleaning liquid can be removed from the second chamber 2 or sulfur-containing molecules can be used to improve cleaning performance. At the exit of the fourth chamber 4 is disposed a drying apparatus 14 which comprises an air knife (not shown) for producing narrow and strong air flow, and a plurality of NIR heating lamps (not shown), so that most part of the cleaning liquid residues can be removed from the shoe parts 6.
With the aforementioned UV radiation system, the present invention provides a pretreatment method for application of coating to shoe parts by UV radiation and then cleaning, the pretreatment method comprises the following steps:
Preparing a molded shoe part 6 which is made of rubber, EVA, PU or TPU;
Transporting the shoe part 6 with a transport means 5 to a first chamber 1 in which being disposed with UV lights, subjecting the surface of the shoe part 6 to ozone activating and etching by radiating it with UV-C rays with a wavelength of 200-280 nm;
Transporting the shoe part 6 with the transport means 5 to a second chamber 2 in which being disposed a cleaning device, removing micro substances from the surface of the shoe part 6 by cleaning it with the cleaning device;
Transporting the shoe part 6 with the transport means 5 to a third chamber 3 which is functionally the same as the first chamber 1, subjecting the surface of the shoe part 6 to ozone activating and etching by radiating it with UV-C rays again; and
Selectively transporting the shoe part 6 with the transport means 5 to a fourth chamber 4 which is functionally the same as the second chamber 2, and cleaning it for the second time.
The speed of the transport means 5 is set to ensure that the shoe part 6 stays long enough in the first chamber 1 for a better reaction with ozone and UV-C rays.
As shown in
What described above are the embodiment of the pretreatment method for application of coating to shoe parts in accordance with the present invention and the UV radiation system. As for function and effects of the UV radiation system of the present invention, reference had to the following description.
As shown in
The following tables 1-3 present the experimental results which the bonding performances of the shoe parts 6 to adhesives. The experiments are conducted by the following steps: placing the shoe parts 6 in a first chamber 1 and radiating it with 2.0-5.0 J/cm UV-C rays, thus producing 30-80 ppm ozone; moving the shoe parts 6 to a second chamber 2 and cleaning it with cleaning liquid, water and ultrasonic waves; moving the shoe parts 6 to a third chamber and radiating it with 2.0-5.0 J/cm UV-C rays, thus producing 30-80 ppm ozone; finally moving the shoe parts 6 to a fourth chamber 4 and cleaning it with clean water and ultrasonic waves to get the results of room temperature pulling test, washing and pulling test, and hydrolysis and pulling test of the shoe parts, as follows:
It is obvious from the above description that, with the pretreatment method for application of coating to shoe parts and the UV radiation system in accordance with the present invention, the coating pretreatment to the shoe parts can be carried out continuously in an automatic manner. Besides, creating etching effect by using UV-C radiation and ozone activating can truly improve the bonding of the shoe parts to the adhesives, without substantial increase in equipment cost. For different shoe parts 6 with different material properties, the UV radiation system of the present invention can be provided with more reaction chambers for UV-C radiation and cleaning, so as to increase the breadth of application of the UV radiation system. Subjecting the surface of the shoe parts 6 to UV-C radiation and cleaning process more than one time can activate the surface, and improve the follow-up coating quality.
While we have shown and described various embodiments in accordance with the present invention, it is clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.