Field of invention:
This invention relates to the composition of stone paper and
more particularly it relates to the process for its production
thereof. The present invention is based on inorganic filler
materials and non-toxic resins or organic binding materials in
addition to Titanium Dioxide to give a snowy-white paper.
Background of the Invention:
Traditional methods of paper making uses enormous amount of
water to grow trees and then, they are cut leading to
deforestation which causes further scarcity of water.
Traditional methods of paper making emits 80% more greenhouse
gases which is causing severe pollution since paper making
requires cutting lot of trees which instead can absorb large
amount of CO2 release during emission of greenhouse gases.
Traditional methods involves usage of chemicals like dyes,
inks, bleach and sizing which can be harmful to the
environment when they are released into water supplies and
nearby land after use.
Chinese Patent Publication No. CN1651649A reports a method for
producing synthetic paper composed of an inorganic mineral
powder such as polyolefin and heavy calcium carbonate, which
is composed of 30 to 50% by weight of a polyolefin blend, 40-
60% natural inorganic mineral powder composition, natural
inorganic mineral powder and carrier resin by twin screw
extruder granulation, made of masterbatch, and then the
masterbatch and polyolefin mixture and additives mixed even by
double Screw extruder, T-die die to get synthetic paper.
Synthetic paper contains a high content of resin, so not only
high cost and because the use of large number of resin,
resulting in waste of resources, cannot be called stone paper.
Chinese Patent No. CN102154931A discloses a stone paper and a
processing method. Wherein the stone paper is composed of 1 to
30 parts by weight of an organic component and 70-85 parts by
weight of an inorganic component, and the stone paper is
obtained by kneading, granulating and calendaring by kneading.
Another US Patent reports a stone paper and a processing
method. Wherein the spherical calcium carbonate having a
surface inlaid caprolactum polymer formed by the addition of
caprolactum to the surface microporous spherical calcium
carbonate.
The present invention involves a method wherein stone paper
composed of 60-80% filler materials as a source of calcium
carbonate mixed with 15 to 45% non-toxic resins and 5%
additives and stabilizer. The key process of present invention
is material milling. The source of calcium carbonate as
limestone, calcite, marble, wollastonite after ultra- fine
grinding machine, processed, discharging more than (1250 mesh)
superfine powder. After special craft processing, ultra-fine
powder is mixed with 15% binding agents in the either form of
HDPE, PE, PLA or PP and eventually adding 5% additives in the
form of Titanium Pigment White 6 then the final product is the
stone paper.
Significance of the Invention:
The main significance of the present invention is to provide
stone paper which involves the process of material milling.
The other significance of the invention is to provide an
alternative of a plant fiber paper which own the same writing
and printing characters and also has the core characters of
plastic packing materials.
The other significance of the invention is to provide a
solution for eco-friendly paper without having any dependence
on plant fiber.
The other significance of the invention is to provide a
solution for paper making without wasting water, cutting Trees
and eliminating strong chemicals and acids.
Object of the Invention:
The principal object of the invention is to provide a stone
paper which is neither pulp nor synthetic but is a kind of
extremely durable, highly strong and eco-friendly.
Another object of invention is to get rid of the dependence of
papermaking on plant fiber, the waste water from papermaking
is eliminated and acids are not utilized in production thereby
making it non-toxic and food safe.
Another further object of invention is to provide aprocess of
paper production which is cost effective and less time taken
comparatively other traditional method of paper production.
Another further object of the invention is to provide a Stone
papers with highly durable, highly strong and eco-friendly and
also has the characteristics like Tear Resistant, Water
Proof, Grease Repellant, Fire Resistant, Total Recyclable,
Photodegradable and Moisture Proof.
Summary of the invention
1. According to the present invention, a new stone paper
comprising inorganic filler materials calcium carbonate(50-
80%) , non-toxic resins or organic binding materials(15-
45%) and additives and stabilizers(5%)
1. Another embodiment of the invention is the filler materials
used in the either form of limestone, Marble, Calcite, and
Wollastonite as a source of calcium carbonate.
2. Another embodiment of the invention is either of theHigh
Density polyethylene, Polypropylene, Polylactic Acid,
Polyvinyl chloride used as an organic binding material.
3. Another embodiment of the invention is Titanium dioxide
(Tio2) which is used as an additive and stabilizer.
4. Another embodiment of the invention, a process of making
stone paper which comprises following steps.
a) Calcium carbonate (filler material) is grinded into nano
sized stone powder of particle size distribution 1250 mesh.
b) The Filler material, organic binding material and Titanium
Dioxide are then compounded in mixing equipment for 15-20
min.
c) Then they are passed to high pressure circular Kneading
Equipment
d) The resulting hydrous paste is then used to make granules
in granulation machine
e) The granules or pellets are then loaded into Multi-Extruder
with an auto loader
f) The pellets are then heated at 1850C for 8-10 min. to obtain
semi liquid paste.
g) Molding process takes place followed by redrying undergoes
through stretching and molding machines installed three in
series.
h) After molding, thickness testing is done through thickness
testing machine.
i) The origin paper (un-coated paper) is sent to Side cutting
and Scrap winding.
j) Then the origin paper is sent to cooling equipment to
normalize mugginess.
k) Finally it is sent to Coating Machine which uses PE
(Polyethylene) or Non-Vulcanized Rubber for one or double
sided coating.
5. Another embodiment of the invention is that the total
production time is around 35-45 min.
6. Another embodiment of the invention is wherein around 200-
225kg of stone paper of thickness 0.04mm and length 1400mm.
is produced.
Detailed Specification of invention
The present invention is a stone paper manufactured from
combining 50-80% calcium carbonate powder mixed with 15 to 45%
organic binding material for eg. High Density
polyethylene(HDPE), Polypropylene (PP), Polylactid Acid (PLA),
Polyvinyl chloride (PVC)and 5%Titanium Dioxide (TiO2) as
additives and stabilizer.
The key process of making stone paper is material milling.
Basically the source of Calcium carbonate is used either in
the form of limestone, marble, calcite and wollastoniteas
inorganic filler material. Then it is compounded with organic
Binding agents in the form of either PP, HDPE, PE, PLA, After
that Titanium Pigment White 6 as an additives are added.
Stone paper manufacturing involves two main steps:-
1. Pelletizing
2. Extrusion
Pelletizing involves following steps:-
a) Calcium carbonate is processed and converted into a nano
sized stone powder
b) Ultra-fine stone powder is then mixed with pure white
silica powder.
c) Non- toxic resins are then fabricated with the stone powder
d) Using pelletizing equipment the composition is converted
into paper pellets.
Extrusion involves following steps:-
a) Stone paper pellets are converted into a base paper by
using rolling equipment.
b) Shaping process is carried out by treating the base paper.
c) It is further treated to obtain a snowy white writing
paper.
d) The writing paper is then cut into an applicable size.
Example 1: Stone paper made out of Limestone( Filler Materials)
using Organic Binding Material as HDPE ( High Density
Polyethylene).
An ultra-fine powder of limestone 50-80% (1500-2500 mesh of
particle size) distribution of around D97:10 micron, 15-45% of
aqueous liquefied of High Density Polyethylene are combined with
Pigmentation Stabilizer( TiO2 white) in Mixing equipment for 15-
20 minutes. The homogenous mixture is then passed through high
pressure circular Kneading Equipment (modification treatment) to
have level handed material. Further the hydrous paste of
(limestone- HDPE) passed through Granulation machine to obtain
stone paper pellets of uniform size. After that granules are
loaded into Multi- Extruder with an auto loader through suction
process which requires 100-250 kPA atmospheric pressure. Then
the pellets are heated at 185oC for 8-10 minutes for converting
them into semi-liquid form. The semi liquid form is then passed
through dewatering equipment for molding of the flaky paper. The
re-drying process is the continuous procedure which occurs for
duration of about 8-20 min, the time duration depends +upon the
kind and size of the stone paper.The stretching and molding
machines are installed in series one after the other. The molded
stone paper is continuously rolled up and down on three- roller
calendar before it pass through a tension machine to increase
the toughness and robustness of the stone paper is tested by
thickness testing. Now the stone paper is sent to remove the
edge waste i.e. (Side cutting and Scrap Winding) before passing
through the cooling equipment in order to normalize the
mugginess of the stone paper. The origin paper (uncoated paper)
is then send through a coating machine which uses the PE
(polyethylene) or non- vulcanized rubber for one side coating or
double side coating. The whole process takes around 35-45
minutes after which a finished roll of stone paper of weight
200-225 kg, thickness 0.04mm and length of 1400mm is obtained.
Example 2:- Stone paper made out of Limestone(Filler Materials)
using Bio-resin Binding Material as PLA (Poly Lactid Acid)
An ultra-fine powder of limestone (1500-2500) mesh of particle
size distribution of around D97:10 micron, 15-45% of aqueous
liquefied of Poly Lactic Acid (Virgin content) are combined with
Pigmentation Stabilizer( TiO2 white) in Mixing equipment for 15-
20 minutes. The homogenous mixture is then passed through high
pressure circular Kneading Equipment (modification treatment) to
have level handed material. Further the hydrous paste of
(limestone- PLA) passed through Granulation machine to obtain
stone paper pellets of uniform size. After that granules are
loaded into Multi- Extruder with an auto loader through suction
process which requires 100-250 kPA atmospheric pressure. Then
the pellets are heated at 185oC for 8-10 minutes for converting
them into semi-liquid form. The semi liquid form is then passed
through dewatering equipment for molding of the flaky paper. The
re-drying process is the continuous procedure which occurs for
duration of about 8-20 min, the time duration depends upon the
kind and size of the stone paper. The stretching and molding
machines are installed in series one after the other. The molded
stone paper is continuously rolled up and down on three- roller
calendar before it pass through a tension machine to increase
the toughness and robustness of the stone paper and is tested by
thickness testing. Now the stone paper is sent to remove the
edge waste i.e. (Side cutting and Scrap Winding) before passing
through the cooling equipment in order to normalize the
mugginess of the stone paper. The origin paper (uncoated paper)
is then send through a coating machine which uses the PE
(polyethylene) or non- vulcanized rubber for one side coating or
double side coating. The whole process takes around 35-45
minutes after which a finished roll of stone paper of weight
200-225 kg, thickness 0.04mm and length of 1400mm is obtained.

Claims:
We claim:
1. A new stone paper comprising inorganic filler materials
calcium carbonate(50-80%), non-toxic resins or organic binding
materials(15-45%) and additives and stabilizers(5%)
2. A new stone paper as claimed in claim 1 wherein the filler
materials are used in the either form oflimestone, Marble,
Calcite, and Wollastoniteas a source of calcium carbonate.
3. Anew improved stone paper as claimed in claim 1 wherein
either of the High Density polyethylene(HDPE),
Polypropylene (PP), Polylactid Acid (PLA), Polyvinyl
chloride (PVC)is used as an organic binding material.
4. A newstone paper as claimed in claim 1 wherein Titanium
dioxide (TiO2)is used as an additive and stabilizer.
5. A process of making stone paper which comprises following
steps:
a) Grinding of calcium carbonate (filler material) into nano
sized stone powder of particle size distribution 1250 mesh.
b) Mixing of the calcium carbonate powder, organic binding
material and Titanium Dioxide in mixing equipment for 15-20
min.
c) Passing the above mixture through high pressure circular
Kneading Equipment.
d) Formation of granules or pellets by the hydrous paste
obtained by kneading equipment.
e) Loading of the granules or pellets into Multi-Extruder with
an auto loader
f) Heating of the pellets at 1850C for 8-10 min. to obtain semi
liquid paste.
g) Dewatering of the semi liquid paste followed by the molding
of the paper through stretching and molding machines
installed three in series for 10-15 min.
h) Thickness testing through thickness testing machine.
i) Side cutting and Scrap winding of the origin paper (uncoated
paper)
j) Cooling of the origin paper by cooling equipment to
normalize mugginess.
k) Coating of the origin paper for one or double sided coating
using PE (Polyethylene) or Non-Vulcanized Rubber by coating
machine.
6. A new stone paper substantially as herein before described
with reference to the accompanying examples.
7. A process for making stone paper substantially as herein
before described with reference to the accompanying
examples.