DESC:TECHNICAL FIELD OF THE INVENTION
[1] The present invention relates to a waterproofing membrane and a method for fabricating thereof. Particularly, the present invention relates to a waterproofing membrane in the form of sheet-like laminate and a method for fabrication thereof.
BACKGROUND OF THE INVENTION
[2] In civil engineering, concrete buildings are constructed either with at least one or two basements (structures below ground) or without basement depending on usage, land availability and budget. While buildings with basements are protected with known waterproofing membrane before construction of the structure, the buildings without basements are generally not sufficiently protected against rising dampness, efflorescence, water seepage, soil settlement and corrosion.
[3] Typical commercial waterproofing membranes used for buildings are Bituminous membranes like Bituminous based Damp Proof Course (DPC), Liquid Bituminous DPC, Bituminous sheet based DPC, and Polyethylene based sheets like High Density Poly Ethylene (HDPE) membrane, Ethylene propylene diene monomer (EPDM) sheet, Liquid Acrylic DPC etc. Although, these kinds of waterproofing membranes are widely used, their performance is hindered by multiple limitations. One of the limitations of these kinds of membranes is that it does not form complete film/barrier for the structures. Moreover, these membranes cannot be applied on damp or wet surfaces. In addition, these membranes cannot resist water under pressure. Further, these membranes cannot prevent damage from termite and rodent infestation. In addition, these membranes cannot be applied over rammed earth or envelope system. These membranes can fail due to settlement of earth and also cannot ensure structural protection from rusting of reinforcements, and hence, very low life cycle of membranes.
[4] Therefore, there is a dire need to provide a waterproofing membrane and a method for fabricating a waterproofing membrane which can overcome the drawbacks mentioned above.
SUMMARY OF THE INVENTION
[5] The present invention provides a waterproofing membrane in the form of a sheet-like laminate and a method for fabricating the waterproofing membrane.
[6] In one aspect, the present invention provides the waterproofing membrane in the form of sheet-like laminate that comprises at least one carrier sheet having a top operative surface and a bottom operative surface. The carrier sheet comprises a predetermined amount of medium density polyethylene, a predetermined amount of linear low density polyethylene, and a predetermined amount of roterproof material. The waterproofing membrane includes at least one adhesive layer having a top operative surface and a bottom operative surface. The adhesive layer is configured to be adhered on said top operative surface of said carrier sheet. The adhesive layer comprises a hot melt pressure sensitive adhesive (HMPSA). The waterproofing membrane includes a protective coating layer having a top operative surface and a bottom operative surface. The said protective coating layer is optionally configured to be adhered on said top operative surface of said adhesive layer. The waterproofing membrane includes a removable release sheet optionally configured to be adhered on said top operative surface of said protective coating layer.
[7] In accordance with the embodiments of the present invention, the predetermined amount of medium density polyethylene is in the range of 50 wt.% to 74 wt.% of the total weight of said carrier sheet. The predetermined amount of linear low density polyethylene is in the range of 24 wt.% to 48% wt% of the total weight of said carrier sheet. The predetermined amount of roterproof material is in the range of 1 wt.% to 2 wt.% of the total weight of said carrier sheet.
[8] In accordance with the embodiments of the present invention, the roterproof material includes a micro-porous polymer that is filled with a plurality of bitter compounds and at least one UV compound. The roterproof material facilitates repellence to rodents and termite from attacking polymers and also retardation of UV degradation of plastics. The UV compound is Denatonium benzoate.
[9] In accordance with the embodiments of the present invention, the hot melt pressure sensitive adhesive comprises a predetermined amount of styrene-isoprene-styrene block, a predetermined amount of petroleum resin, a predetermined amount of hydrotreated naphthenic distillate, and a predetermined amount of antioxidants.
[10] In accordance with the embodiments of the present invention, the predetermined amount of styrene-isoprene-styrene block copolymer is in the range of 15 wt.% to 40% wt.% of the total weight of said hot melt pressure sensitive adhesive. The predetermined amount of petroleum resin is in the range of 25 wt.% to 60 wt.% of total weight of said hot melt pressure sensitive adhesive. The predetermined amount of hydrotreated naphthenic distillate is in range of 15 wt.% to 30% wt.% of total weight of said hot melt pressure sensitive adhesive. The predetermined amount of antioxidants is in the range of 25 wt.% to 45 wt.% of total weight of said hot melt pressure sensitive adhesive.
[11] In accordance with the embodiments of the present invention, the carrier sheet has a thickness in the range of 0.5 mm to 2.5 mm. The adhesive layer has a thickness in the range 0.05 mm to 2.5 mm. The protective coating layer has a thickness in the range of 0.2 mm to 0.6 mm. The release sheet has a thickness in the range of 0.01 mm to 0.13 mm.
[12] In accordance with the embodiments of the present invention, the protective coating layer comprises a coating or dusting of finely divided inorganic particulate material on an outer exposed surface thereof. The inorganic particulate material comprises at least one of sand, calcium carbonate, cement, titanium dioxide dusted thereon.
[13] In accordance with the embodiments of the present invention, the release sheet comprises a film or paper that is coated with a release agent. The release agent is silicone. The film is selected from at least one of polyethylene, polypropylene, polyethylene terephthalate, and polyamide.
[14] In accordance with the embodiments of the present invention, the waterproofing membrane has a tensile strength in the range of 16 MPa to 35 MPa. The waterproofing membrane has an elongation in the range of 400% to 1000%. In addition, the waterproofing membrane has a puncture resistance in the range of 600 N to 1200 N.
[15] In another aspect, the present invention provides a method for fabricating a waterproofing membrane. The method comprises the following steps:
a. preparing a carrier sheet, wherein said method of preparation of the carrier sheet comprising the steps of:
i. providing a mixture of materials comprising a predetermined amount of medium density polyethylene, a predetermined amount of linear low density polyethylene and a predetermined amount of roterproof material;
ii. pre heating an extrusion die head, a feeding barrel and an extrusion roll;
iii. drying said mixture of materials at a temperature in the range of 90 °C to 120 °C to obtain a dried mixture of material;
iv. feeding said dried mixture of materials to said preheated feeding barrel;
v. transporting said molten material mixture from the feeding barrel to said extrusion die head via a melt pump; and
vi. subjecting said extrusion die head for extruding a carrier sheet to the calendaring rollers to obtain a roll of the carrier sheet,
b. coating the carrier sheet with adhesive layer, wherein said method of coating further comprising the steps of:
i. obtaining a hot melt pressure sensitive adhesive (HMPSA) and storing into a HMPSA tank;
ii. pre-heating a coating die head and the HMPSA tank at a temperature in the range of 145 °C to 160 °C;
iii. adjusting a gap between the coating die head and rollers based on the sheet thickness to obtain the coating of desired thickness;
iv. loading the roll of the carrier sheet obtained in step (a) onto an unwinding section of the coating machine;
v. locking the roll and joining the roll to the previous sheet;
vi. maintaining the sheet edges within the marked guide lines with the help of a sensor to reach 3-hour mark;
vii. setting desired roll length in the rewinding section panel; and
viii. pressing the die head onto the surface of the sheet once the sheet starts moving to obtain the waterproofing membrane.
[16] In accordance with the embodiments of the present invention, the predetermined amount of medium density polyethylene is in the range of 50% wt.% to 74 wt.% of the total weight of said carrier sheet, the predetermined amount of linear low density polyethylene is in the range of 24 wt.% to 48% with respect to wt% of the total weight of said carrier sheet and the predetermined amount of roterproof material is in the range of 1 wt.% to 2 wt.% with respect to the total weight of said carrier sheet.
[17] In accordance with the embodiments of the present invention, pre heating of the extrusion die head, feeding barrel and extrusion roll is carried out at a temperature in the range of 200 °C to 250 °C and for a time period in the range of 2 hours to 5 hours.
[18] In accordance with the embodiments of the present invention, the adhesive layer is optionally coated with a protective coating layer (C) or a removable release sheet.
[19] In accordance with the embodiments of the present invention, the protective coating layer comprises a coating or dusting of finely divided inorganic particulate material on its outer exposed surface. The inorganic particulate material comprises sand, calcium carbonate, cement, titanium dioxide dusted thereon.
[20] In accordance with the embodiments of the present invention, the removable release sheet comprises a film or paper that is coated with a release agent. In one preferred embodiment, the release agent is silicone and the film is selected from at least one of polyethylene, polypropylene, polyethylene terephthalate, and polyamide. It is understood however that the type of release agent and the selection of film may vary as per intended application of the present invention.
[21] In accordance with the embodiments of the present invention, the roterproof material comprises a micro-porous polymer filled with bitter plurality of compounds and at least one UV compound.
[22] In accordance with the embodiments of the present invention, the hot melt pressure sensitive adhesive comprises a predetermined amount of styrene-isoprene-styrene block copolymer in the range of 15 wt% to 40% of total weight of said hot melt pressure sensitive adhesive, a predetermined amount of petroleum resin in range of 25 wt.% to 60 wt.% of total weight of said hot melt pressure sensitive adhesive, a predetermined amount of hydrotreated naphthenic distillate in range of 15 wt.% to 30% wt.% of total weight of said hot melt pressure sensitive adhesive, and a predetermined amount of anti oxidants in the range of 25 wt.% to 45% wt.% of total weight of said hot melt pressure sensitive adhesive.
[23] Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawing, illustrating by way of example the principles of the invention.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWING
[24] The detailed description is described with reference to the accompanying figures.
Figure 1 depicts a cross-section of a waterproofing membrane of the present invention having two layers;
Figure 2 depicts a cross-section of a waterproofing membrane of the present invention having three layers;
Figure 3 depicts a cross-section of a waterproofing membrane of the present invention having four layers; and
Figure 4 shows termite testing of the membrane of the present invention.
Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF THE INVENTION
[25] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the invention as defined by the description. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
[26] The terms and words used in the following description are not limited to the bibliographical meanings but are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of the present invention is provided for illustration purpose only.
[27] It is to be understood that the singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise.
[28] Referring to Figures 1-3, according to an aspect, the present invention discloses a waterproofing membrane in the form of sheet-like laminate comprising at least one carrier sheet (A) having a top operative surface and a bottom operative surface. The carrier sheet (A) comprises a predetermined amount of medium density polyethylene, a predetermined amount of linear low density polyethylene and a predetermined amount of a roterproof material. The waterproofing membrane comprises at least one adhesive layer (B) having a top operative surface and a bottom operative surface. The adhesive layer (B) is configured to be adhered on said top operative surface of said carrier sheet (A). The adhesive layer (B) comprises a hot melt pressure sensitive adhesive (HMPSA). The waterproofing membrane comprises a protective coating layer (C) having a top operative surface and a bottom operative surface. The protective coating layer (C) is optionally configured to be adhered on the top operative surface of the adhesive layer (B). The waterproofing membrane comprises a removable release sheet (D) optionally configured to be adhered on said top operative surface of said protective coating layer (C).
[29] In accordance with the embodiments of the present invention, the predetermined amount of styrene-isoprene-styrene block copolymer is in the range of 15 wt.% to 40% wt.% of the total weight of said hot melt pressure sensitive adhesive. The predetermined amount of petroleum resin is in the range of 25 wt.% to 60 wt.% of total weight of said hot melt pressure sensitive adhesive. The predetermined amount of hydrotreated naphthenic distillate is in range of 15 wt.% to 30% wt.% of total weight of said hot melt pressure sensitive adhesive. The predetermined amount of antioxidants is in the range of 25 wt.% to 45 wt.% of total weight of said hot melt pressure sensitive adhesive.
[30] In accordance with the embodiments of the present invention, the predetermined amount of medium density polyethylene is in the range of 50 wt.% to 74 wt.% of the total weight of said carrier sheet. The predetermined amount of linear low density polyethylene is in the range of 24 wt.% to 48 w.t% of the total weight of said carrier sheet. The predetermined amount of roterproof material is in the range of 1 wt.% to 2 wt.% of the total weight of said carrier sheet.
[31] In a preferred embodiment, the carrier sheet (A) of the waterproofing membrane laminate has medium density polyethylene of 64% of total weight of the carrier sheet (A), linear low density polyethylene of 35 wt% of total weight of the carrier sheet (A) and a roterproof material of 1% of total weight of the carrier sheet (A). The medium density polyethylene in accordance with the present invention provides mechanical strength, flexibility and waterproofing integrity for the membrane along with very high elongation (above 600%) and workability.
[32] In accordance with the embodiments of the present invention, the roterproof material comprises a micro-porous polymer filled with a plurality of bitter compounds and at least one UV compound. The carrier sheet typically has a thickness of about 0.5 mm to 2.0 mm, with a composite thickness of preferably about 0.7 mm to 2.5 mm and comprises of a granular or smooth surface as is provided by films, sheets, fabrics, and extrusion coated woven and non-woven fabrics. The Medium density polyethylene is ethylene 1-hexene copolymer. The MDPE has a density/specific gravity of 0.935 g/cm3 (ASTM D792)and a melt flow index (190 C/2.16 kg) (ASTM D1238) of 0.5 g/10min. The medium density polyethylene in the carrier sheet provides impact resistance, and puncture resistance. The medium density polyethylene facilitates toughness that allows to make thinner carrier sheet without compromising the strength of the material. The linear low density polyethylene provides the carrier sheet with high flexibility, elongation and increased adaptability which increases the workability. The linear low density polyethylene has a density/specific gravity of 0.918 g/cm3 (ASTM D792) and a melt flow index (190 C/2.16 kg) (ASTM D1238) of 2.0 g/10min. One such example of the linear low density polyethylene is ethylene 1-butene copolymer. The micro-porous polymer filled with bitter compounds and UV compounds are added to the carrier sheet for repelling rodents and termite from attacking polymers and also to achieve retardation of UV degradation of plastics. The micro-porous polymer also protects the membrane from damaging effects of UV and heat exposure. The major bitter compound is Denatonium benzoate with additional additives.
[33] In accordance with the embodiments of the present invention, the waterproofing membrane may optionally include additional layers of material on either face of the carrier sheet as desired. For example, a bottom operative surface of a second adhesive layer is configured to be adhered to the top operative surface of the first adhesive layer. The first adhesive layer is configured to be adhered either directly onto a surface of the carrier sheet, or indirectly if there is an optional additional layer of material interposed between the carrier sheet and the adhesive layer.
[34] In accordance with the embodiments of the present invention, the adhesive layer (B) is configured to be adhered to the carrier sheet (A) such that the membrane will stick to the required surface without the use of heat or additional bonding agents. The adhesive layer (B) comprises a hot melt pressure sensitive adhesive (HMPSA). The HMPSA comprises a predetermined amount of styrene-isoprene-styrene block copolymer in the range of 15 wt.% to 40 wt.% of total weight of said hot melt pressure sensitive adhesive. The HMPSA comprises a predetermined amount of petroleum resin in range of 25 wt.% to 60 wt.% of total weight of said hot melt pressure sensitive adhesive. The HMPSA comprises a predetermined amount of hydrotreated naphthenic distillate in range of 15 wt.% to 30 wt.% of total weight of said hot melt pressure sensitive adhesive. The HMPSA comprises a predetermined amount of anti oxidants in the range of 25 wt.% to 45 wt.% of total weight of said hot melt pressure sensitive adhesive.
[35] In accordance with the embodiments of the present invention, the adhesive layer (B) has a thickness in the range 0.05 mm to 2.5 mm, preferably is in the range of 0.07 mm to 2.0 mm, more preferably is in the range of 0.1 mm to 1.0 mm, most preferably is in the range of 0.2 to 0.5 mm.
[36] In accordance with the embodiments of the present invention, the protective coating layer (C) includes a coating or dusting of finely divided inorganic particulate material on an outer exposed Surface thereof. The particulate inorganic material serves to protect the adhesive layer from the elements prior to casting concrete against it. The protective coating layer (C) also improves the adhesion to concrete during casting. The particulate inorganic material includes the protective coating of finely divided particulate material at least one of sand, calcium carbonate, cement, titanium dioxide, etc., dusted thereon. The protective coating layer (C) has a thickness that is in the range of 0.2 mm to 0.6 mm.
[37] In accordance with the embodiments of the present invention, the protective coating layer (C) comprises a coating or dusting of finely divided inorganic particulate material on an outer exposed surface thereon. The inorganic particulate material comprises at least one of sand, calcium carbonate, cement, titanium dioxide dusted thereon. The release sheet (D) has a thickness that is in the range of 0.01 mm to 0.13 mm.
[38] In accordance with the embodiments of the present invention, the removable release sheet (D) comprises a film or paper that is coated with a release agent. The film may comprise at least one of polyethylene, polypropylene, polyethylene terephthalate, or polyamide. A paper release sheet may also be coated with a polyolefin layer prior to being coated on the polyolefin face with a silicone release agent. The release agent is silicone. The removable release sheet can be used to prevent the adhesive portion of the membrane from adhering to the carrier sheet or other portion of the membrane when the membrane is rolled up. The removable release sheet is usually removed from the membrane prior to or during installation.
[39] In accordance with the embodiments of the present invention, the waterproofing membrane has a tensile strength in the range of 16 MPa to 35 MPa. The waterproofing membrane has an elongation in the range of 400% to 1000%. The waterproofing membrane has a puncture resistance in the range of 600 N to 1200 N.
[40] In another aspect, the present invention provides a method for fabricating a waterproofing membrane. The method comprises a step (a) of preparing a carrier sheet (A) and a step (b) of coating the carrier sheet (A) with an adhesive layer (B), and optionally step (c) of coating the adhesive layer (B) with a protective coating layer (C) or a removable release sheet (D). The membranes of the present invention are manufactured with extrusion process and is then passed through a coating line where hot melt pressure sensitive adhesive is applied uniformly on top of membrane and then finished with a protective layer coating as the final layer.
[41] The step (a) of preparing a carrier sheet (A) is described in detail hereinafter. The preparation of the carrier sheet (A) includes the step of providing a mixture of materials, a predetermined amount of medium density polyethylene, a predetermined amount of linear low density polyethylene and a predetermined amount of a roterproof material. In the next step, an extrusion die head, a feeding barrel and an extrusion roll are pre-heated at a temperature in the range of 200 °C to 250 °C for a time period in the range of 2 hours to 5 hours. In the further step, the mixture of materials is dried at a temperature in the range of 90 °C to 120 °C to obtain a dried mixture of material. In the next step, the dried mixture of materials is fed to the preheated feeding barrel. The molten material mixture is transported from the feeding barrel to extrusion die head via a melt pump. In further step, the extrusion die head is subjected for extruding a carrier sheet to the calendaring rollers to obtain a roll of the carrier sheet.
[42] The step (b) of coating the carrier sheet (A) with adhesive layer (B) is described hereinafter which comprises an initial step of obtaining a hot melt pressure sensitive adhesive (HMPSA) and storing into a HMPSA tank. In the next step, a coating die head and HMPSA tank are preheated at a temperature range of 145 °C to 160 °C. In the next step, a gap between the coating die head and rollers is adjusted based on the sheet thickness to obtain the desired coating thickness. In further step, the roll of the carrier sheet obtained in step (a) is loaded onto the unwinding section of the coating machine locking the roll and joining start portion of the roll to the end portion of the previous roll in order to reduce wastage of material, manpower. The sheet edges are maintained within the marked guidelines with the help of a sensor to reach 3 hour mark thereby preventing wastage of adhesive through the sheet sides. The desired roll length is set in the rewinding section panel. In the final step, once the sheet starts moving, the die head is pressed onto the surface of the sheet to obtain the waterproofing membrane.
[43] In accordance with the embodiments of the present invention, the predetermined amount of medium density polyethylene is in the range of 50 wt.% to 74 wt.% of total weight of the carrier sheet, the predetermined amount of linear low density polyethylene is in the range of 24 wt.% to 48 wt.% of total weight of the carrier sheet and the predetermined amount of roterproof material is in the range of 1 wt.% to 2 wt% of total weight of the carrier sheet.
[44] In accordance with the embodiments of the present invention, the adhesive layer (B) is optionally coated with a protective coating layer (C). The protective coating layer (C) comprises a coating or dusting of finely divided inorganic particulate material on an outer exposed surface thereof. The inorganic particulate material comprises at least one of sand, calcium carbonate, cement, titanium dioxide dusted thereon.
[45] In accordance with the embodiments of the present invention, the adhesive layer (B) is optionally coated with a removable release sheet (D). The removable release sheet comprises a film or paper that is coated with a release agent. The release agent is silicone.
[46] In accordance with the embodiments of the present invention, the roterproof material comprises a micro-porous polymer filled with a plurality of bitter compounds and at least one UV compound.
[47] In accordance with the embodiments of the present invention, the hot melt pressure sensitive adhesive comprises a predetermined amount of styrene-isoprene-styrene block copolymer in the range of 15 wt.% to 40 wt.% of total weight of said hot melt pressure sensitive adhesive, a predetermined amount of petroleum resin in range of 25 wt.% to 60 wt.% of total weight of said hot melt pressure sensitive adhesive , a predetermined amount of hydrotreated naphthenic distillate in range of 15 wt.% to 30 wt.% of total weight of said hot melt pressure sensitive adhesive, and a predetermined amount of anti oxidants in the range of 25 wt.% to 45% wt.% of total weight of said hot melt pressure sensitive adhesive.
[48] Example 1: Fabrication of waterproofing membrane, in accordance with the present invention
Step a: preparing a carrier sheet.
The carrier sheet is made with MDPE as the major raw material by the process of extrusion. Raw materials (MDPE mixed with LLDPE and anti-termite, rodent and ant masterbatch) are fed into the extrusion line through hopper, after which it is melted and pumped to die head after which it is extruded through a series of rollers. The detailed procedure is mentioned below.
The raw materials were mixed in the amounts of 64 wt.%% of MDPE, 35 wt.% of LLDPE, 1 wt% of roterproof material. The Extrusion die head, feeding barrels and extrusion rolls were pre-heated at a temperature range of 200 °C to 250 °C for 3 hours before starting the extrusion process. The Raw material with Anti Rodent master batch was loaded into the mixer-dryer machine. The material was pre heated at 100 °C in the mixer-dryer before being sucked into the barrel screw. The melt pump and main pump were switched ON and the material starts to flow from the funnel to the T-die head. Once the material starts coming out of the T-die head uniformly, the calendaring rollers were taken forward to the T-die head and the sheet was fed into the calendaring rollers. The desired sheet thickness was set using the gap between the calendaring rollers and the adjustment bolts on the T-die head. The edge trimming blades were set at the desired width ensuring minimum wastage (cutting waste of less than 4 cm width on both sides). Once the desired sheet quality and thickness is achieved, the extrusion line speed is increased to maximize production capacity. Respectively all the rollers’ speeds were adjusted accordingly. The jumbo rolls were winded based on the membrane thickness and cut once the winder reaches the capacity (say 300 meters to 500 meters according to the thickness). The sheet thickness was monitored regularly (every 30 minutes) on both the sides and throughout the width at the cutting of every rolls. The sheet thickness was maintained within the tolerance limit to ensure minimal raw material consumption. The testing of properties of the sheet was done every 3 hours to ensure that the sheet maintains the desired quality.
Step (b) coating the carrier sheet (A) with adhesive layer (B)
The extruded sheet was coated with an HMPSA (Hot melt pressure sensitive adhesive) layer. Particularly, the coating die head and HMA tanks were pre-heated at a temperature range of 145 °C to 160 °C before the coating step commences. The gap between the coating head and roller was adjusted based on the sheet thickness and the grade of the sheet so that the desired coating thickness is achieved. The die gap was adjusted based on the sheet thickness using the adjusting screws. The jumbo rolls from the extruder were loaded onto the unwinding section of the coating machine. Once the roll was properly locked in, it was joined to the previous membrane using double sided tape. The membrane edges were maintained within the marked guide lines with the help of a sensor. Once the 3-hour mark has been reached, the coating process begins. The desired roll length was set in the rewinding section panel. Once the membrane starts moving, the die head was pressed onto the surface of the same. The line speed can be controlled using the coating panel. Speed starts off slow and was then gradually increased to optimize the production. Glue coating thickness and width was measured and adjusted. Once the roll reaches set roll length (20 meters) at the rewinding section, the machine cuts and packages the roll automatically when the panel was set to auto. The packaged roll was then unloaded using the push button and placed onto a trolley. After each jumbo roll was finished at the unwinding section, move the rolls from the trolley to storage area so that they can be easily loaded and dispatched.
[49] Testing of the waterproofing membrane obtained in accordance with the present invention
Test 1: Strength
Table 1: Shows test results for waterproofing membrane tested for various strength test methods
Sr. no. Test Conducted Unit Test Results Test Method
1 Tensile Strength – Longitudinal N/mm2 29.85 ASTM D 412-2016
2 Elongation – Longitudinal % 554 ASTM D 412-2016
3 Tensile Strength – Transverse N/mm2 26.30 ASTM D 412-2016
4 Elongation - Transverse % 894 ASTM D 412-2016
5 Puncture Resistance N 764 ASTM E 154-2008
6 Peel Adhesion with Fresh Concrete N/m 1810 ASTM D 903: 1988
7 Peel Adhesion with Hard Concrete N/m 1370 ASTM D 903: 1988
8 Depth of Water Permeability @ 7 Bar Mm Nil EN 12390-8-2019
9 Tensile strength-mean N/mm2 32 ASTM D 412-2016
From the above table 1, it is evident that waterproofing membrane showed superior mechanical properties compared to the membranes that are presently used in the industry.
[50] Test 2: Termite Testing:
Methodology
An active termite mount was identified before the initiation of study. The membrane of the present invention and the conventional membrane samples having length 10 cm and width 3 cm were prepared and placed randomly near the termite mount in the field. The membrane of the present invention and the conventional membrane samples were buried near termite mount at 15 cm depth to ease the access of samples for termites. The membrane of the present invention and the conventional membrane samples were observed for the infestation of termites qualitatively at day 1 and weekly intervals up to 4 weeks. Summary of results presented in Table 2.
Table 2: Test results for chemical resistance
Sr. No. Test Item Mean Percent (%) Repellency over control - 4 week after treatment
1 membrane of the present invention (T1) 78.57
2 conventional membrane (T2) -
From above Table 2 and Figure 4, it is evident that, the membrane of the present invention and the conventional membrane samples that were exposed to termites for four weeks and there was no termite infestation observed in any of treatment replications up to two weeks including untreated control. Third week onwards infestations were observed both in treatment and untreated control. The results were expressed based on the visual observation of nest building observed on treatment and control. No bite markings were observed. Hence, it is concluded from the present study that the test sample of the present invention exhibited 78.57 % repellency against termites compared to Untreated conventional membrane samples for a period of 4 weeks study under field conditions.
[51] Test 3: Testing for chemical resistance:
The testing was done as per the ASTM C 868-2002 method.
Table 3: Test results for chemical resistance
Sr. No. Test Conducted Unit Test Results
1 Chemical Resistance -
10% Sulphur-7Days Visual No disintegration, blistering, swelling, peeling or cracking
2 Chemical Resistance - 10 % Phosphorous - 7 Days Visual No disintegration, blistering, swelling, peeling or cracking
3 Chemical Resistance -Sea Water-7 Days Visual No disintegration, blistering, swelling, peeling or cracking
4 Chemical Resistance -10% HCL-7 Days Visual No disintegration, blistering, swelling, peeling or cracking
5 Chemical Resistance -10% NaOH 7 Days Visual No disintegration, blistering, swelling, peeling or cracking
From above table 3, it is evident that the membrane of the present invention showed no disintegration, blistering, swelling, peeling or cracking against 10% Sulphur, 10% Phosphorous, Sea Water, 10% HCL and 10% NaOH.
[52] Test 4: Efficacy testing of treated and control HDPE membrane samples against Monomorium pharaonis species of ants
Field having required ant species was identified and the field collected population were transferred into laboratory and allowed to acclimatize for a period of one week. The ants were kept in approximately 40 x 30 cm size boxes with appropriate feed and water sources and kept in dark room with artificial light source. The membrane of the present invention and the conventional membrane samples having length 10 cm and width 3 cm were prepared and kept in box for choice treatment method. The test item was exposed for a period of 30 days within the enclosure. Number of ants visit towards food (sugar granules) which was placed on test samples were recorded from the experimental enclosure box on day 1, 10, 20 and 30 at time point 1, 2, 3, 4 and 24 Hrs., post treatment. During experiment visual mortality were also recorded. After exposure it was cleaned and observed under microscope for any damage marks on the test samples surface.
Table 4: Shows summary of efficacy test results against ant
Name of sample Assessment day(s) Average number of ants visited to food (sugar granules) on test item % Anti-Ant Activity (Repellency)
membrane of the present invention 01 3.00 91.43
10 4.33 84.88
20 3.67 86.25
30 2.67 88.73
conventional membrane sample 01 35.00
-
10 28.67
20 26.67
30 23.67
From the above table 4, it is evident that membrane of the present invention and the conventional membrane samples that during experiment 24.67 % visual ant mortality was observed. There was NO sign of damage on both test samples during experiment. The results were expressed as % Anti-Ant Activity (Repellency) based on the number of ants visited to food (sugar granules) on both samples. % Anti-Ant Activity (Repellency) on day 1,10, 20 and 30 post treatment were recoded as 91.43%, 84.88%, 86.25%, 88.73% respectively. Hence, it is concluded from the present study that the membrane of the present invention is effective over control against Monomorium pharaonis ants as compared to the conventional membranes.
[53] Test 5: Rodent repellency test for the membrane of the present invention and the conventional membranes against Rat, Rattus rattus, under laboratory condition
Methodology:
The field-collected rodents Rattus rattus, species were used for the experiment. Collected rodents were acclimatized under laboratory conditions in the study chamber (20 m3) before the initiation of the experiment. During acclimatization, rodents were fed with rat feed and water ad libitum.
Preparation of Sample
One membrane of the present invention and an untreated conventional HDPE membrane having length 10 cm and width is 3 cm was taken for exposure. The supplied samples were evaluated as follows:
Choice Method:
The membrane sample of the present invention of 10 cm length and 3 cm width weighed and placed in one corner of the study chamber. Likewise, untreated conventional HDPE membrane of same size sample was also weighed and placed in the opposite corner of study chamber. One rodent was released inside the chamber. HDPE membrane sheets exposed to rodents for up to four weeks. Tap water and standard laboratory chow were also provided ad libitum during complete exposure period. The observations of bite markings were recorded on Day 1, Week 1, 2, 3 and 4. The experiment was replicated thrice.
Non-Choice Method:
The membrane sample of the present invention of 10 cm length and 3 cm width weighed and placed in corner of the study chamber. One rodent was released inside the chamber. Untreated conventional HDPE membrane of same size samples also weighed and kept in another chamber and rodent was released. HDPE membrane samples were exposed to rodents for 5 days. Tap water was provided during the complete exposure period. The observations of bite markings were recorded on Day 1, 3 and 5. The experiment was replicated thrice. The summary of results is presented in tables 5 and 6.
Table 5: Choice method
Name of sample Time Average reading (no of bite marking) % Anti-Ant Activity (Repellency)
membrane of the present invention Day 1 0.00 100.00
Week 1 0.00 100.00
Week 2 0.00 100.00
Week 3 0.67 93.94
Week 4 1.67 88.64
conventional membrane sample Day 1 0.33
-
Week 1 2.33
Week 2 6.00
Week 3 11.00
Week 4 14.67
Table 6: non-choice method
Name of sample Time Average reading (no of bite marking) % Anti-Ant Activity (Repellency)
membrane of the present invention Day 1 0.00 100.00
Day 3 0.00 100.00
Day 5 0.67 90.48
conventional membrane sample Day 1 1.33
-
Day 3 3.00
Day 5 7.00
From the above tables 5 and 6, the results of the study indicated that the percent repellency over conventional membrane sample @ timepoints of Day 1, Week 1, 2,3 and 4 by the Choice method was found 100.00 %, 100.00 %, 100.00%, 93.94% and 88.64.% respectively for the membranes of the present invention. Further, the results of the study indicated that the percent repellency over conventional membrane sample @timepoints of Day 1, 2, and 5 after exposure period by the non-Choice method was found 100.00 %, 100.00 %, and 90.48 % respectively for membranes of the present invention. Hence, it is concluded from the present study that the membranes of the present invention exhibited effective repellency against Rattus rattus species of rodents when tested under laboratory conditions.
[54] Similar to example 1, the waterproofing membrane was prepared in Example 2 for composition in the amounts of 74 wt.%% of MDPE, 24 wt.% of LLDPE, and 2 wt% of roterproof material, in Example 3 for composition in the amounts of 50 wt.%% of MDPE, 48 wt.% of LLDPE, and 2 wt% of roterproof material and subjected to tests 1- 5 as of Example 1 and found superior test results.
[55] The membrane of the present invention is advantageous in that it has very good resistance to water pressure from the below structure and very low water absorption percentage of the membrane ensures complete protection for structure against water ingress. Further, the membrane of the present invention is both termite and rodent proof, thereby protecting structure from the attacks of termite, rodents and other parasites.
[56] The thickness of the membrane can start from 0.7 mm offering superior flexibility and making it lighter, ensures increased ease of handling. The membrane of the present invention also offers very high adaptability due to high flexibility with effective joint sealing features. The membranes can be applied directly on surfaces including rammed earth without any concrete finishing. The plain cement concrete (PCC) can be poured directly on to the membrane and the membrane will get bonded to concrete because of pressure bonding.
[57] The terms and words used in the following description are not limited to the bibliographical meanings but are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of the system is for the purpose of understanding and nowhere limit the invention. The abovementioned parts nowhere limit the invention and are provided for understanding of the invention.
[58] Although there has been shown and described the preferred embodiment of the present invention, it will be readily apparent to those skilled in the art that modifications may be made thereto which do not exceed the scope of the appended claims. Therefore, the scope of the invention is only to be limited by the following claims.
LIST OF REFERENCE NUMERALS
A carrier sheet
B adhesive layer
C protective coating layer
D removable release sheet
,CLAIMS:
1. A waterproofing membrane in the form of sheet-like laminate comprising:
at least one carrier sheet (A) having a top operative surface and a bottom operative surface, said carrier sheet (A) comprises a predetermined amount of medium density polyethylene, a predetermined amount of linear low density polyethylene and a predetermined amount of roterproof material;
at least one adhesive layer (B) having a top operative surface and a bottom operative surface, said adhesive layer (B) configured to be adhered on said top operative surface of said carrier sheet (A), said adhesive layer (B) comprises a hot melt pressure sensitive adhesive (HMPSA);
a protective coating layer (C) having a top operative surface and a bottom operative surface, said protective coating layer (C) optionally configured to be adhered on said top operative surface of said adhesive layer (B); and
a removable release sheet (D) optionally configured to be adhered on said top operative surface of said protective coating layer (C).
2. The waterproofing membrane as claimed in claim 1, wherein said predetermined amount of medium density polyethylene is in the range of 50 wt.% to 74 wt.% of the total weight of said carrier sheet.
3. The waterproofing membrane as claimed in claim 1, wherein said predetermined amount of linear low density polyethylene is in the range of 24 wt.% to 48% wt% of the total weight of said carrier sheet.
4. The waterproofing membrane as claimed in claim 1, wherein said predetermined amount of the roterproof material is in the range of 1 wt.% to 2 wt.% of the total weight of said carrier sheet.
5. The waterproofing membrane as claimed in claim 1, wherein said roterproof material includes a micro-porous polymer filled with a plurality of bitter compounds and at least one UV compound.
6. The waterproofing membrane as claimed in claim 5, wherein said UV compound is Denatonium benzoate.
7. The waterproofing membrane as claimed in claim 1, the hot melt pressure sensitive adhesive includes a predetermined amount of styrene-isoprene-styrene block copolymer in the range of 15 wt.% to 40 wt.% of total weight of said hot melt pressure sensitive adhesive.
8. The waterproofing membrane as claimed in claim 1, the hot melt pressure sensitive adhesive includes a predetermined amount of petroleum resin in range of 25 wt.% to 60 wt.% of total weight of said hot melt pressure sensitive adhesive.
9. The waterproofing membrane as claimed in claim 1, the hot melt pressure sensitive adhesive includes a predetermined amount of hydrotreated naphthenic distillate in range of 15 wt.% to 30% wt.% of total weight of said hot melt pressure sensitive adhesive.
10. The waterproofing membrane as claimed in claim 1, the hot melt pressure sensitive adhesive includes a predetermined amount of anti oxidants in the range of 25 wt.% to 45 wt.% of total weight of said hot melt pressure sensitive adhesive
11. The waterproofing membrane as claimed in claim 1, wherein said carrier sheet (A) has a thickness in the range of 0.5 mm to 2.5 mm.
12. The waterproofing membrane as claimed in claim 1, wherein said adhesive layer (B) has a thickness in the range of 0.05 mm to 2.5 mm.
13. The waterproofing membrane as claimed in claim 1, wherein said protective coating layer (C) has a thickness in the range of 0.2 mm to 0.6 mm.
14. The waterproofing membrane as claimed in claim 1, wherein said release sheet (D) has a thickness in the range of 0.01 mm to 0.13 mm.
15. The waterproofing membrane as claimed in claim 1, wherein said protective coating layer (C) comprises a coating or dusting of finely divided inorganic particulate material on an outer exposed surface thereof.
16. The waterproofing membrane as claimed in claim 1, wherein said inorganic particulate material comprises at least one of sand, calcium carbonate, cement, titanium dioxide dusted thereon.
17. The waterproofing membrane as claimed in claim 1, wherein said release sheet (D) comprises a film or paper that is coated with a release agent.
18. The waterproofing membrane as claimed in claim 17, wherein said film is selected from at least one of polyethylene, polypropylene, polyethylene terephthalate, and polyamide.
19. The waterproofing membrane as claimed in claim 17, wherein said release agent is silicone.
20. The waterproofing membrane as claimed in claim 1 has a tensile strength in the range of 16 MPa to 35 MPa.
21. The waterproofing membrane as claimed in claim 1 has an elongation in the range of 400% to 1000%.
22. The waterproofing membrane as claimed in claim 1 has a puncture resistance in the range of 600 N to 1200 N.
23. A method for fabricating a waterproofing membrane, said process comprising the following steps:
a. preparing a carrier sheet (A), wherein said method of preparation of the carrier sheet comprising the steps of:
i. providing a mixture of materials comprising a predetermined amount of medium density polyethylene, a predetermined amount of linear low density polyethylene and a predetermined amount of a roterproof material;
ii. pre heating an extrusion die head, a feeding barrel and an extrusion roll;
iii. drying said mixture of materials at a temperature in the range of 90 °C to 120 °C to obtain a dried mixture of material;
iv. feeding said dried mixture of materials to said preheated feeding barrel;
v. transporting said molten material mixture from the feeding barrel to extrusion die head via a melt pump; and
vi. subjecting said extrusion die head for extruding a carrier sheet to the calendaring rollers to obtain a roll of the carrier sheet.
b. coating the carrier sheet (A) with adhesive layer (B), wherein said method of coating further comprising the steps of:
i. obtaining a hot melt pressure sensitive adhesive (HMPSA) and storing into a HMPSA tank;
ii. pre-heating a coating die head and the HMPSA tank at a temperature in the range of 145 °C to 160 °C;
iii. adjusting a gap between the coating die head and rollers based on the sheet thickness to obtain the coating of desired thickness;
iv. loading the roll of the carrier sheet obtained in step (a) onto the unwinding section of the coating machine;
v. locking the roll and joining the starting portion of the roll to the end portion of the previous roll sheet;
vi. maintaining the sheet edges within the marked guide lines with the help of a sensor to reach 3-hour mark;
vii. setting desired roll length in the rewinding section panel; and
viii. pressing the die head onto the surface of the sheet once the sheet starts moving to obtain the waterproofing membrane.
24. The process as claimed in claim 23, wherein said extrusion die head, said feeding barrel and said extrusion roll are preheated at a temperature in the range of 200 °C to 250 °C for a time period in the range of 2 hours to 5 hours.
25. The process as claimed in claim 23, wherein the predetermined amount of medium density polyethylene is in the range of 50 wt.% to 74% of the total weight of said carrier sheet.
26. The process as claimed in claim 23, wherein the predetermined amount of linear low density polyethylene is in the range of 24 wt.% to 48 wt.% of the total weight of said carrier sheet.
27. The process as claimed in claim 23, wherein the predetermined amount of roterproof material is in the range of 1 wt.% to 2 wt.% of total weight of said carrier sheet.
28. The process as claimed in claim 23, wherein said adhesive layer (B) optionally coated with a protective coating layer (C).
29. The process as claimed in claim 28, wherein said protective coating layer (C) comprises a coating or dusting of finely divided inorganic particulate material on an outer exposed surface thereof.
30. The process as claimed in claim 29, wherein said inorganic particulate material comprises at least one of sand, calcium carbonate, cement, titanium dioxide dusted thereon.
31. The process as claimed in claim 23, wherein said the adhesive layer (B) optionally coated with a removable release sheet (D).
32. The process as claimed in claim 31, wherein said removable release sheet comprises a film or paper that is coated with a release agent.
33. The process as claimed in claim 32, wherein said film is selected from at least one of polyethylene, polypropylene, polyethylene terephthalate, and polyamide.
34. The process as claimed in claim 32, wherein said release agent is silicone.
35. The process as claimed in claim 23, wherein said roterproof material comprises a micro-porous polymer filled with a plurality of bitter compounds and at least one UV compound.
36. The process as claimed in claim 35, wherein said UV compound is Denatonium benzoate.
37. The process as claimed in claim 23, wherein the hot melt pressure sensitive adhesive comprises a predetermined amount of styrene-isoprene-styrene block copolymer is in the range of 15 wt% to 40 wt.% of total weight of said hot melt pressure sensitive adhesive.
38. The process as claimed in claim 23, wherein a predetermined amount of petroleum resin is in range of 25 wt.% to 60 wt.% of total weight of said hot melt pressure sensitive adhesive.
39. The process as claimed in claim 23, wherein a predetermined amount of hydrotreated naphthenic distillate is in range of 15 wt.% to 30% wt.% of total weight of said hot melt pressure sensitive adhesive.

40. The process as claimed in claim 23, wherein a predetermined amount of anti oxidants is in the range of 25 wt.% to 45 wt.% of total weight of said hot melt pressure sensitive adhesive.