S. C. Sahoo & B. N. Mohanty of Indian Plywood Industries Research &Training Institute (IPIRTI)
There is a greater awareness of the need for materials in an expanding world population and increasing affluence. There are vast supplies of agricultural fibre residues in India. Bagasse, Jute, Straws, and Sisal Appear to hold the most promises for continued development. In general, lignocellulosic non-wood fibers are alternative and inexpensive. Composite manufacturing using bagasse furnish is an option for utilization in areas where this material is abundant. The adhesive has an important influencing on mechanical and physical properties of agro-based composites. UF (urea-formaldehyde) and PF (Phenol- Formaldehyde) modified with 20 to 30 percent of pMDI (4, 4’-diphenylmethanediisocyanate) has provided substantially increased mechanical and physical properties of agro-based composites compared to a single UF or PF application of agrobased composites.
The development of natural fiber composite in India is based on a two pronged strategy of preventing detection of resources as well as ensuring good economic return. Phenolic resin is one of the first synthetic resins exploited commercially for the preparation of jute composite products mainly because of its high heat resistance, low smoke emission, excellent fire retardant properties and compatibility with jute fibers. Phenolic resin based jute fiber composite products have been used for quite some time as certain substitutes for wood. So the objective of this study is to utilize jute felt for replacing face and glue core veneers to have solid dense hard body and for bonding with wood in flush door manufacture to have all properties of wooden flush door shutter giving a scope of using it as an alternative source of wood.
From the study, it can be inferred that PF resin impregnated non-woven Jute Fiber Felt can suitably replace the face and glue core veneers from flush door shutter of solid core wood type. Impregnated Jute Fiber Felt has also been found to bond wellwith wooden stiles and rails used for making frame and with batten in fills as per requirement. These findings prove that Jute Fiber Felt has polarity like wooden veneer to bond with stiles and rails as well as batten in fills and also get converted to hard dense body when pressed in hot press and may act as veneer. Moreover, the aqueous resin system utilized for impregnation was found compatible to Jute Felt as Jute has some polar functional groups.
During the work compression had been found 75% of the thickness of the Jute Fiber Felt used for the work when hot pressed at specific pressure of 16 Kg/cm2. Resin medium used for impregnation had been prepared of higher water tolerance and of flow time of 14-16 seconds through B4 cup (IS: 3944). The reason for using such low condensed resin is to have suitable drainage of resin through the non-woven jute fiber felt medium used for higher retention. Different dilutions of resin medium have been done with a view to ensure economy in the system. If resin medium is used alone, without dilution, then cost of product will be more or less similar to traditional wooden flush door shutter due to high retention of undiluted resin medium in the felt. In this work, dilution level has been restricted to 1: 2 because beyond this level results of the flush door shutter have been found erroneous and at the level 1:2, results of flush door shutter are not fully satisfactory. Appearance and on the basis of weight of flush door shutter, it may be graded as 1: 0 > 1: 1 > 1: 1.5 > 1: 2. From the above gradation and from the look it may be said that the product needs proper finish with increase of dilution to attract markets. Without any finish, colour of flush door shutter is brownish black as shown in figure 4.
figure 4
To make the product appealing to the market the product requires either colour finish or use of plastic lamination available in the market as overlay.
For application of paint on the surface of the door, synthetic enamel paints have been used and they have been found quite compatible with the face surface of finished impregnated jute fiber felt. Before application of colour paint, all the surfaces of the doors require sanding. Sanded surfaces then require application of wood primer to have uniformity on the surface. Finally, after the application of primer, paint can be sprayed as per desired finish of the surface as shown in figure 5
figure 5
Similarly, for lamination on the surface, sanding operation is required for proper bonding of laminates with adhesives as shown in figure 6. Flush door shutter of solid core type has been made using jute composite in the form of nonwoven fiber felt of weight 1900 to 1950 gm/m2 and of thickness 10 mm by impregnating with low condensed PF resin liquid (resol type of 50% solid content). In addition to this, particle-reinforced composite board made from jute stick available from stem of jute plant was also used for the development of this product... Some of the physicomechanical properties like surface roughness, moisture content, density, water absorption, swelling, compressive strength, Internal bond strength, static bending strength, screw and nail holding strength, glue shear strength etc .of the flush door shutter manufactured by using jute felt and jute stick has been studied
figure 6.
Flush door shutters were subjected to evaluation as per IS: 2202 (Part -1) 1999, and found satisfactory to all tests up to dilution level 1:1.5. Protection of wooden frame as used in making of flush door shutter, For productivity on the mechanical process is to be applied for impregnation and drying of impregnated felt. Usually impregnation work is done by means of spraying and by passing hot air. So from the study it has been concluded that wood substituted jute composites could be an ideal solution with ever depleting forest reserves, utilization of renewable resources will beneficiary for Flush door industries to meet the challenge during the scarcity of wood material and reduce the landed cost of imported wood material.