FORM 2
THE PATENTS ACT 1970
(39 of 1970)
AND
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rulel3)
1. TITLE OF THE INVENTION:
"MANUFACTURING OF FIBRE CEMENT ACCESS FLOOR CORE BY
HATCHECK PROCESS"
2. APPLICANT:
(a) NAME: EVEREST INDUSTRIES LIMITED
(b)NATIONALITY: Indian Company incorporated under the Companies Act, 1956
(c) ADDRESS: Gat 152, Lakhmapur Village, Dindori Taluka,
Post Bag No.5, District Nashik -422202, Maharashtra, India.
3. PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is to be formed.

FIELD OF INVENTION:
The present invention relates to Development and Manufacturing of the fibre cement access floor core by Hatcheck process.
BACKGROUND & PRIOR ART:
Access floor commonly known as raised flooring or raised access computer floor are types of floor that provide an elevated structural floor above a solid substrate, often a concrete slab, to create a hidden void for the passage of mechanical and electrical services. They are widely used in modern office buildings, and in specialized areas such as command centers, IT data centers and computer rooms where there is a requirement to route mechanical services and cables, wiring, and electrical supply. Raised/Access Flooring can be installed at varying heights from 2inches/50mm to heights above 4 ft/1200mm to suit services that may be accommodated beneath. Additional structural support and lighting are often provided when a floor is raised enough for a person to crawl or even walk beneath.
At present days underfloor air distribution is becoming a more common way to cool a building by using the void below the raised floor as a plenum chamber to distribute conditioned air. Access floor has various advatages like
• Modular floor panels can be laid quickly and can be walked upon in no time
• Direct access to the cavity is possible anywhere
• Convenient servicing of data cabling and building management systems
• Versatile to adapt to changing requirements
• The latest interior fit-out solution for offices
Access floor core are finished with various options like Vinyl, Tiles, GI sheets to look aesthetically better.
Conventional calcium sulphate access floor are manufactured with single pulse pressing methods where cellulose and other fibres are mixed for reinforcement.

Various thicknesses of Access floors are available in the market based on the load and deflection requirements. Stringers and other assembly components are use to hold the floor and increase the strength of the construction. Typical dimension of the access floor is 610mmX610mm and thickness varies from 14mm to 40 mm.
The present inventors have attempted to prepare Fiber Cement Access Floor with uniform distribution load and minimum defection.
SUMMARY OF INVENTION:
According to the present invention, a Fiber Cement Access Floor prepared by Hatschek process with uniform distribution load and minimum defection is disclosed. The Fiber Cement Access Floor comprises Soft Wood unbleached kraft pulp, Recuperated pulp from waste kraft, Ordinary Portland Cement with high Specific Surface Area (SSA), Ground Pulverised fly ash with fineness 325 to 400 mesh Wpllastonite, Quartz, Bauxite and micro fine calcite.
Fibre cement Access floor core disclosed in the present invention has unique formulation which gives very high strength and least deflection after load removal. Also, it has very effective and uniform distribution of cellulose and mineral fibrous material achieved by Hatcheck process unlike conventional process and product.
DETAILS OF INVENTION:
The present invention discloses a Fiber Cement Access Floor prepared by Hatschek process with uniform distribution load and minimum defection, characterized in that the formulation comprises, Softwood unbleached Kraft pulp in 1 -3%, Recuperated pulp from waste kraft in 1-3%, Ordinary Portland Cement with Specific Surface Area (SSA) 300-400kg/m2 in 40-45%, Ground Pulverised fly ash with fineness 325 to 400 mesh in 10-20%, Wollastonite in 3-10%, Siliceous material in.10-20%, material derived from Bauxite in 2-6%, micro fine calcite 0 to 4%.

In an aspect, the present invention discloses novel method of manufacturing fibre cement Access floor core by hatcheck process and the unique formulation to take very high uniform distribution load and minimum deflection.
Fiber cement Access floor core made on Hatcheck process ensures very uniform distribution of the individual cellulose and mineral fibres across the core. This uniform distribution helps to get very high strength and required minimum quantity of the fibre unlike conventional press processes. In conventional process, bunches of fibre are mixed in the slurry and uniform distribution is difficult. In hatcheck process, cellulose pulp is refined to very small diameter with higher length which ensures very good dispensability in the slurry. Hatcheck process parameters are set in such a way that the thickness can be built up on forming drum. Specially designed vacuum trays are used to apply uniform and regulate minimum possible vacuum so as to retain maximum moisture in wet sheet which helps to build the high monolayer thickness. Sheets made out of forming drum are subjected to very high hydraulic pressure to remove the excess moisture thereby increase the packing density and strong layer bonding of the sheets. The final hydraulic pressure applied varies from 165 bar to 300 bar depending on the final output required. This process reduces the thickness of the initial sheet to 15-25%.
These pressed boards are then pre-cured for 6-12 hours and then subjected to very high pressure steam curing up to 8-11 kg/cm2 pressure. This results into very high strength Fibre cement access floor. These boards are then cut into desired dimension as per the requirement. These panels are dimensionally stable, high impact strength and durable product as compared to the conventional access floor.
In another aspect, the present invention discloses the formulation of Fibre cement Access floor consist of Softwood unbleached Kraft pulp in an amount of 1 to 3% by weight in combination with Recuperated pulp from waste Kraft in an amount 1 to 3% along with a hydraulic binder, a filler and pozzolonic material, a siliceous material, a fibrous mineral, material derived from Bauxite and micro fine calcite powder.
The hydraulic binder is selected from Portland cement with specific surface area 300 to 400 m2/kg and is present in an amount 40-45% by weight. The filler and Pozzolonic

material is selected form ground pulverized fly ash with fine size 325 to 400 mesh and is present in an amount 10-20% by weight, in some instance it can be replaced with other siliceous material. The siliceous material is selected from quartz, sand powder or high silica compound and is present in an amount 10-20% by weight. The fibrous mineral is Wollastonite present in an amount 3-10%. The material derived from Bauxite ore is present in an amount 2-6% by weight. Micro fine calcite powder in an amount of 0-4% is present.
Further the both the pulp are hydropulped and refined. It is refined to the level of 28-38 deg. SR value to get good filtration and distribution to form mesh on cylinder. This cellulose fibre alongwith other fibrous minerals are so uniformly dispersed in the slurry gives best reinforcement and strength to the product. This uniform distribution helps is making composites with minimum doses than the conventional method. The ordinary Portland cement is a hydraulic binder used to hold the other raw material and to impart the strength. Pozzolonic and reactive material like ground pulverized fly ash reacts with cement and cement byproduct at high temperature during the autoclave process. Bauxite-material derived from Bauxite is used for arresting expansion and shrinkage and also improves the durability of the product with the formation of 11A Al-Tobermorite in the product. Fine granite powder is used to boost the density of the product.
The formulation of Fibre cement access floor core is given in Table no -1 Table 1: Formulation of Fibre cement Access floor core

Raw Material % By Weight
Soft wood unbleached Kraft pulp 1-3
Recuperated pulp from waste Kraft 1-3
Portland cement with specific surface area in range of 300-400 tn2/kg 40-45
Ground Pulverised fly ash fineness 325 - 400 mesh) 10-20
Wollastonite 3-10

Quartz/sand Powder/high silica

compound 10-20
Bauxite/ Material derived from
Bauxite 2-6
Microfine caleite powder 0-4
The manufactured product on Hatcheck machine from above formulation can be made of various thicknesses varying from 15mm to 40mm depending on the requirement.
The density of the product is found to be 1400 to 1600 kg/m3. Panels when tested for ultimate load at centre is found 21.5 KN and ultimate load at the point of weakest is found to be 14.8 KN. Deflection at working load with safety factor of 2 & 3 is found much less and meeting to the top class of deflection i.e. Class A.
Panels when subjected to the soft body and hard body impact load; it easily passes as per the standard BSEN 12825: 2001. New panel is used for each test and is supported with stringers and pedestals
Details of the load properties are listed in table No 2. The properties are observed based on test results of Fibre cement access floor made by Hatcheck process
Static load Tests Table No - 2

Properties Results BSEN 12825: 2001
( Clause 4.1 & 4.2)
requirements
Ultimate Load at centre 21.5 KN( Class 6) Class 1:>4KN Class 2: >6 KN Class 3: > 8 KN Class 4: > 9 KN Class 5: > 10KN Class 6: > 12KN

Ultimate Load at *Point of
14.8 KM ( Class 6) --------do
Weakest
Deflection at Working load 0.9 mm (Class A) Class A : 2.5 mm Max
(Safety factor of 2) Class B: 3.0 mm Max Class C: 4.0 mm Max
Defection at Working laod 0.65 mm ( Class A) do-----
(Safety factor of 3)
Soft Body Impact test Passes Passes
Hard Body Impact test Passes Passes
* - Point of weakest is located at about 200mm X 200 mm from the comer of the panel.

WE CLAIM,
1. A Fiber Cement Access Floor prepared by Hatschek process with uniform
distribution load and minimum defection, characterized in that the formulation
comprising,
(i) Soft wood unbleached Kraft pulp in 1 -3%
(ii) Recuperated pulp from waste Kraft in 1-3%,
(iii) Portland cement with Specific Surface Area in range of 300-400 m2/kg in 40-45%,
(iv) Ground Pulverised fly ash with fineness in range of 325 to 400 mesh in 10-20%,
(v) Wollastonite in 3-10%,
(vi) Siliceous material in 10-20%,
(vii) material derived from Bauxite in 2-6%, and
(viii) Microfine calcite powder in 0-4%.
2. The Fiber Cement Access Floor according to claim 1, wherein said process
comprising,
(i) refining cellulose pulp to very small diameter with higher length to ensure better dispensability in the slurry,
(ii) preparing sheets using specially designed vacuum trays to retain maximum moisture in wet sheet,
(iii) exposing said sheets to very high hydraulic pressure to remove the excess moisture and to increase the packing density & strong layer bonding of the sheets,
(iv) applying hydraulic pressure in range from 165 bar to 300 bar,
(v) pre-curing boards prepared by step (iv) for 6-12 hours and applying high pressure steam curing up to 8-11 kg/cm2 pressure to achieve high strength Fiber Cement Access Floor, and
(vi) cutting cured Fiber Cement Access Floor into desired dimension as per the requirement.

3. The Fiber Cement Access Floor according to claim 1, wherein said siliceous material is selected from quartz, sand powder and high silica compound.