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This invBtitiim rtlmtwrn to « ciMipt»*jtian for cabin sh^Attiing applications.
This Invsntion furtrvar ralataa to a tl^mm ratardantf Icwi saoka coApositlon for cabla shaathlng appllcationa.
PRIOR ART
US Patent No. 4,371,A93 dk«clos«c a «Mak# ratardanfc composition comiprfBing a polymer and afc laaat SB nola pvrcant of * final/ divitfird aulphata 9las« or aalphata glas* - caramic mat»ri«l or a Miittura ttiaraof > TTia culDhata glac* la u«*4 in « proportion of kt laast 5« «ol parcant, Mhich ia a vry high proportion, Tharafopa, an objact o* tha invantlon is to usa laaavP quantity at aulpnata glcaa.
It is an ebjact of this invantlon to DnopoSt a cosposition for cabia sha«thlng Hhich Mill riaduca ssalks ganaration in tht •vent of a cabli fir*.
It is a turthar objact of this intfantton to propoat ii compoaition for csbla sheathing orftich will rasist iha propagatton of fip» if tha t;*bl
A atill further abi*ct of this invention is to proposa a compoaition for cabla shaathing Ht»ich ^anarat^as sinlatua acid gaa wh*n tha cabla bums in a spaclfic stsasphar*.
Yat anoth
Thus mceorttin^ to thi« invmnttan ttt«r* is provided
According to this invention is further provided a process for the
preparation of a composition for sheathing applications
comprising blending a resin, a stabiliser, filler, plasticizeri
processing aid, flame retardant additive and sulphate glass at a
o tet^ierature in the range of 160-170 C to a homogeneous mass.
In accordance with this invention, weighed quantities of the
chemicals based on their molar weights are blended together for
o about 5 to 10 mins. at a temperature in the range of 160 to 170 C
to a homogeneous mass. The mass is optionally pressed into sheets
in a compression molding machine maintained at a temperature in
o the range of 150 to 160 C.
Polyvinyl chloride is used 4S the resin. The stabiliser is selected froat compounds such as, for eg. tribasic lead sulphate and is used in 4 to 7 parts per hundred of the resin.
The filler and plasticizer is selected from compounds such as, for eg. calcium carbonate and tri—octyl-trimellitate respect ively. The filler is used in proport ions of 10 to 30 and the plasticizer in 30 to 40 parts per hundred of the resin. The processing aid is used in a proportion about, for eg. 1 part per hundred of resin and is selected from compounds, such as calcium stearate. The flame—retardant additive is present in the compo¬sition in a proportion of 50 to 60 parts per hundred of the resin. The flame—retardant additive is selected from compounds, such as trihydrated alumina, antimony trioxide, zinc sulphate.
magnesium sulphate and ammonium molybdate. The low melting sulphate glass is present in 5 to 25 parts per hundred of the resin.
In accordance with an embodiment of this inventioni the low melting sulphate glass is prepared by grinding together into a homogeneous mass, weighed quantities of sulphate compounds of elements) such as potassium sodium, zinc, copper and melting the homogeneous mass thus obtained to a fused mass, followed by quench cooling the fused mass to get glass flakes. The glass flakes are then ground and sieved to obtain a fine powder with a Mesh size of 200 to 325.
EXAMPLE I
Polyvinyl chloride (PVC> resin of K~70 grade of India Petro-cheMicals Ltd. and stabi1iser of Waldiee Ltd. have been used. The Chemical equivalent of this resin is also available in the local •arket- Commercial grade chemicals of plasticizer* filler, anti-oxidanti etc. available in the local market have been used. Locally available laboratory grade chemicals have been used for ■ak ing low melting sulphate glass.
Preparation of low melting sulphate glass
Chenicals used and their mole X
Potassium sulphate — 17.6
Sodium sulphate - 23.5
Zinc sulphate - 47.1
Copper sulphate — 11.8
The weighed quanti ties of the above chemicals based on their
nolar weights are grounded together to a homoegenous powder. This
o has been melted in a furnace maintained at 60
After about one hour» the fused mass is quench cooleq to get
glass flakes. The glass obtained is ground to fine pcjwder and
sieved. The sieved glass powder in the mesh size of 200-325i is
used for blending with PVC compositions in different php
levels.
Compounding of PVC
Chenicals used in parts per hundred.
Polyvinylchloride« resin 100
Tribasic lead sulphate, stabiliser 4
Calcium carbonatei filler 10
Trioctyltrimellitate, plasticizer 40
Calcium atearate, processing aid 1
Trihydrated alumina, antimony trioxide,
zinc sulphate, magnesium sulphatei
ammonium molybdate as flame retardant
additives 50
Low melting sulphate glass 15
PVC resin alongwith stabiliser, plasticizer, filleri antiowidant
and flame retardant additives with sulphate glass as special
o additive was blended at 160-170 C using Brabender plasticorder
for 5~i0 minutes. The homogeneous confounded mass has been
converted into sheet spec imens using compression molding machine
o Maintained at 150-160 C. The sheet specimens were used for
evaluation of mechanical and flame retardant properties.
we claims
9. The composition as claimed in clam i Mherein said flame
retardant additive is used in a proportion of 50 to 60 parts per
hundred of the resin.
10* A process for the preparation of the composition as
claimed in claim 1 comprising blending a resin, a stabiliser,
filler, plasticizer, processing aid, flame retardant additive and
o sulphate glass at a temperature in the range of 160 to 170 C to
obtain a homogeneous composition.
11. A process as claimed in claim 10 Mherein said sulphate glass is prepared by grinding together into a homogeneous ntasSf sulphate compounds of elements such as c^otassium, sodium, zinc and copper, melting the homogeneous mass to a fused mass, followed by quench cooling the fused mass to obtain glass flakes, grinding the mass flakes to obtain a fine powder.
12. The process as claimed in claim 11 wherein said glass powder is sieved to obtain a fine pcwMler with a mesh size of 200 to 325.
13. A composition for sheating cables si^stantially as herein
described and illustrated.
14. A process for the preparation of the composition for
sheating cables si^stantially as herein described and
i llustrated.
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