Patent Application
20080070461
The accompanying drawings, which are included to provide a further understanding of the invention and constitute a portion of the specification, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention. In the drawings:
As shown in
According to the operation sequence shown in
As to the step “providing knitted fabric as a substrate”, knitted fabric 11 or warp-knitted fabric 11 having a plurality of pores 181 (as shown in
The structure of the fabric 11 produced by knitting or warp-knitting process is sophisticated other than that produced by weaving process in which warp fibers are simply crossed with weft fibers. Hence, the fringe will not appear at the edge of knitted fabric 11 of warp-knitted fabric 11.
As far as the step “dipping the substrate in the coating”, about 40%-50% by weight of resin, about 20%-30% by weight of Titanium dioxide (TiO2), about 30%-40% by weight of flame retardant, about 1%-2.5% by weight of wetting agent, appropriate amount of pigment and water are well mixed as the coating 13 in advance. After that, the coating 13 is poured into the trough 14. During the operation of the apparatus 1, the fabric 11 is guided by the rollers 12 and completely dipped into the coating 13 within the trough 14.
The resin in the coating 13 is used for setting the shade sheet 18. The resin may be selected from a group of melamine resin, acrylic resin, urea-formaldehyde resin, and emulsion resin.
TiO2 is used to add shading effect of the shade sheet 18.
The material of the flame retardant depends on that of the fabric 11. For example, when the fabric 11 is made of polyster fiber, the flame retardant may be selected from a group of brominated pentaerythriol and polyphosphoricacid ester.
The wetting agent is used to enable the shade sheet 18 having the gloss and tactility of the fabric 11 so as to prevent the shade sheet 18 from hardening and embrittling due to the cured coating 13. The wetting agent may be selected from a group of alkylaryl ether and polyethylene glycol.
The color of the pigment mainly determines that of the shade sheet 18 so that proper pigment with desired color may be selected and added into the coating 13.
Amount of added water has to enable the coating 13 with proper concentration or viscosity to be adapted for the operation in subsequent step “blow-drying the substrate soaked by coating”. In contrast to the conventional technique described in the “Background of the Invention”, the concentration or viscosity of the coating 13 used in the present invention is lower to facilitate the coating 13 received within the pores 181 to be blown off by the blowing device 161 during the blow-drying step. However, the scraper used in the conventional technique aims at forcing the coating with higher concentration or viscosity into the pores.
When the fabric 11 is upwards drawn out of the trough 14, some of tiny pores 181 may not be soaked by the coating 13 although the surfaces of the fabric 11 is stuck with the coating 13. Consequently, the fabric 11 soaked by coating 13 has to be pressed by the pair of pressing wheel 15 so as to squeeze the coating 13 sticking on the surface of the fabric 11 into the tiny pores 181 and simultaneously forcing the surplus coating 13 dropping back into the trough 14.
Next, the step of blow-drying the substrate soaked by coating is performed in the blow-drying area 16. The fabric 11 soaked by coating 13 may be blown by hot air directly. Alternatively, this step may be further divided into two sub-steps: blowing step and baking step. During the blowing sub-step, the coating 13 received within the pores 181 is blown off by the air which is sent from the blowing device 161. Accordingly, the pores 181 are revealed in the fabric 11 again to enable the shade sheet 18 to have a predetermined light transmittance. Besides, the forced air also carries some vapor out of the coating 13. Then, the fabric 11 soaked by coating 13 proceeds into the baking device 162 to evaporate water in the coating 13. For example, a heater or infrared emitter (not shown) may be installed in the baking device 162 to provide a zone with about 180 Celsius degrees. The slightly extensible fabric 11 is stretched by the rollers 12 during the steps described above. However, after the fabric 11 exits out of the baking device 162, the fabric 11 is set in shape by dried resin in the coating 13 and then the shade sheet 18 is produced.
The set shade sheet 18 further proceeds and passes through the cooling area 17. A plurality of cooling wheels 171 is arranged within the cooling area 17 to prolong the path for natural cooling. Alternatively, another blowing appliance (not shown) may be equipped in the cooling area 17 to perform forced cooling against the shade sheet 18.
The shade sheet 18 leaving from the cooling area 17 may be winded into a cylinder roll for storage or transportation. Alternative, the shade sheet 17 may be cut into pieces with determined dimensions for being made into curtains or other shades.
This invention has been disclosed in terms of specific embodiments. It will be apparent that many modifications can be made to the disclosed structures without departing from the invention. Therefore, it is the intent of the appended claims to cover all such variations and modifications that are within the breadth and scope of this invention.
