FIELD OF INVENTION
The present invention relates to SiC impregnated rubber hose. In particular, the invention relates to means of achieving a composite material of Silicon Carbide and natural rubber. The invention also relates to hose making using the composite material prepared by the invented process exhibiting excellent wear resistance and flexibility.
BACKGROUND OF INVENTION
The present invention relates to a hose for transporting abrasive materials and to a process for its production of the composite material of Silicon carbide and natural rubber.
In industries, abrasive materials such as coal, powdered glass, various metals, etc. in material conveying, pneumatic conveying system (like in coke injection, mineral processing industry etc), mining slurry conveying often require handling. Traditionally these materials are handled by plastic and/or elastomeric material hoses, often connected to suction and/or propulsion systems.
But because of the properties of the hose constituent materials (i.e. plastic material) and of the transported materials (which abrade the hose within which they are transported), the hose deteriorates rapidly and this leads to very frequent replacement; these hoses are usually replaced, for example, every week.
These results decrease in production & losses due to a higher number of shutdowns, high inventory of hoses and requirement of skilled manpower for maintenance.
To overcome these drawbacks, plastic and/or elastomeric material hoses have been produced provided with a plurality of protection elements consisting of sintered alumina ceramic tiles or sleeves embedded in the hose body. But, these ceramic lined rubber hose has its disadvantages. These ceramic lined rubber hose are complex to manufacture, costly and has very less flexibility.
We aim to invent a rubber hose with flexibility like a rubber hose with excellent wear resistance like an alumina ceramic lined rubber hose.
Silicon carbide [SiC] ceramics and composite materials have high hardness, good strength, high thermal conductivity and good creep and excellent abrasion resistance at room temperature as well as high temperatures. These attractive mechanical and thermal properties have led to their use in several applications in wear-resistant seals/rings/nozzles, coatings, metal-matrix composites, kiln furniture, silicon carbide heating elements, body & vehicle armour, and many more like fluid-handling, aeronautics, energy, and process, electronic, ballistic and nuclear industries. One of the possible ways to utilize the unique properties of exceptional wear resistance is to make a composite material of elastomer and SiC for the construction of hose.
However, there have been several challenges involved in making composite material of elastomer and silicon carbide which will have excellent wear resistance.
Accordingly, it is an object of the invention to construct a hose using the composite material which will overcome the above drawbacks mentioned before.

SUMMARY OF THE INVENTION
In one aspect, the present disclosure provides a process for preparing the composite material of elastomer and silicon carbide comprising the steps of:
1. Preparing cross grit of equal volume of SiC grits.
2. Spraying bonding solution on top of the scattered SiC cross grits
3. Mixing NR on a two roll mill with peptizer masticated.
4. Slowly adding the grits to the mill and mixed at 25°C temperature.
5. The chemicals were added to the rubber batch after ensuring the grits are suspended
properly.
The invention disclosed herein is construction of a hose using the composite material.
BEIEF DESCRIPTION OF THE DRAWINGS
Figure 1: A construction of the hose using the SiC rubber composite material.
Figure 2: Microstructure image of silicon carbide reinforced rubber composite 60% of silicon carbide powder and 40% of natural rubber.
Figure 3 Microstructure image of silicon carbide reinforced rubber composite 50% of silicon carbide powder and 50% of natural rubber.
Figure 4 Microstructure image of silicon carbide reinforced rubber composite 40% of silicon carbide powder and 60% of natural rubber.
Figure 5: Microstructure image of silicon carbide reinforced rubber composite 30% of silicon carbide powder and 70% of natural rubber.
Figure 6: Microstructure image of silicon carbide reinforced rubber composite 25% of silicon carbide powder and 75% of natural rubber.
Figure 7: Weight of the flexible rubber hose fabricated using different composition of the composite (with the flexible rubber hose having length of 2 meter and 62mm diameter)
DESCRIPTION OF THE INVENTION
For the purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification are to be understood as being modified in all instances by the term "about". It is noted that, unless otherwise stated, all percentages given in this specification and appended claims refer to percentages by weight of the total composition.

The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only, and in no way limits the scope and meaning of the invention or of any exemplified term. Likewise, the invention is not limited to various embodiments given in this specification.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the case of conflict, the present document, including definitions will control.
It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the content clearly dictates otherwise. Thus, for example, a reference to a “solvent” may include two or more such solvents.
The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.
As used herein, the terms “comprising” “including,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only, and is not intended to limit the scope of the invention in any manner.
Thus, before describing the present invention in detail, it is to be understood that this invention is not limited to the following particular embodiment. The description of a particular embodiment and examples provided herein are only for the purpose of illustration and does not limit the scope of the invention to the particular embodiment.
In one aspect, the present disclosure provides the process for preparing the composite material of elastomer and silicon carbide. The steps are:
1. Two different grit size (eg. 24 Mesh Size, 36 Mesh Size) of SiC is taken of equal volume.
2. SiC grits are mixed well together.
3. SiC grits are kept spread to a thick plastic sheet.
4. Bonding solution is sprayed on top of the scattered SiC cross grits
5. Natural rubber is mixed on a two-roll mill with peptizer masticated.

4. Slowly the grits were added to the mill and mixed at 25°C temperature. The weight
ratio of grits and natural rubber is 3:2 .
5. The chemicals were added to the rubber batch after ensuring the grits are suspended
properly.
In yet another aspect, the present disclosure provides a means to the process of using this SiC rubber composite material in hose construction. The process consists of the following steps:
1. The SiC rubber composite material is put in the calendaring machine and a composite material sheet is produced. That flexible SiC rubber compound sheet is wrapped about a mandrel in plural layers. It has been made sure that lubricating oil is applied to the mandrel before wrapping the sheet.
2. The first layer of elastomeric material is then applied.
3. The first fabric (polyester, nylon, glass fibres, aramid fibres, etc.) reinforcement layer is wrapped about the elastomeric material layer.
4. The galvanized iron wire reinforcement is coiled spirally over the first fabric reinforcement.
5. The second layer of elastomeric material is then applied.
6. A further fabric reinforcement layer applied to the second layer of elastomeric material.
7. Afterwards, at least one further layer of elastomeric material is applied as the final covering for the hose (plastic and/or elastomeric material).
In one aspect, the present disclosure provides the construction of the hose as described
earlier.
A hose of the invention having the a fore described characteristics (rubber compound,
elastomeric materials, steel spirals, fabric reinforcements) is described in detail below.
EXAMPLES
Example 1:
At first, the SiC rubber compound is prepared as follows:
1. Two different grit size 24 Mesh Size and 36 Mesh Size of green SiC (Around 99% Purity) is taken of equal volume.
2. SiC grits are mixed well together.
3. SiC grits are kept spread to a thick plastic sheet.

4. Bonding solution (Elastomer adhesive) is sprayed on top of the scattered SiC cross grits.
5. Natural rubber is mixed on a two-roll mill with peptizer masticated.
6. Slowly the grits were added to the mill and mixed at 25°C temperature. The weight ratio of grits and natural rubber is 3:2 .

7. The chemicals were added to the rubber batch after ensuring the grits are suspended properly.
The construction of the hose is as follows:
1. The SiC rubber composite material is put in the calendaring machine and a composite material sheet is produced. That flexible SiC rubber compound sheet is wrapped about a mandrel in plural layers. The layer thickness is the thickness of 2-25 mm. It is formed of a natural rubber blend of 55 ± 5 Shore A hardness. This layer is particularly elastic and has abrasion resistance.
2. The first layer of elastomeric material is then applied having 55 ± 5 Shore A hardness.
3. A first fabric (polyester, nylon, glass fibres, aramid fibres, etc.) reinforcement layer is wrapped about the elastomeric material layer. The reinforcement layer is composed of cellulose or polyester or polyamide or aramid textile threads laid at an angle from 45 to 60° in 1 or multiple layers (up to 3) depending upon the working pressure requirement.
4. The galvanized iron wire ( diameter 1 to 5 mm.) reinforcement is coiled spirally over the first fabric reinforcement. It ensures circularity of the hose when bent, and also ensures good resistance to 1 bar vacuum.
5. The second layer of elastomeric material which is identical to the first elastomeric material is then applied.
6. A further fabric reinforcement layer identical to the first fabric layer is applied to the second layer of elastomeric material.
7. Afterwards, at least one further layer of elastomeric material is applied as the final covering for the hose (plastic and/or elastomeric material). 60 ± 5 Shore A hardness. It is particularly resistant to abrasion, atmospheric agents and ozone. Alternatively, an EPDM blend can be used to make it particularly resistant to high temperatures and to aggressive chemical substances.
It was found that a hose constructed in this manner was able to convey highly abrasive
materials for several months without replacement and has a great degree of flexibility
than Ceramic Lined rubber hose and also it is lightweight than ceramic lined rubber hose.
These inventions are advantageous because it increases the life of the hose in practical
application and very easy to handle.
The hose and process developed in this manner can be modified in endless variants, all
these will fall within the scope of the inventive concept; moreover, all the details can be
replaced by technically equivalent elements.
In the practical scenario, the material of construction and dimensions can be decided
according to the requirements.
Example 2:

The silicon carbide reinforced rubber composite was prepared with 60% of silicon carbide powder and 40% of natural rubber and further processed into a flexible rubber hose with steps as follows.
1) The black silicon carbide powders of 99% purity having average diameter of 710microns and 500microns were taken in equal proportions and mixed together.
2) The mixed silicon carbide powders are spread in a plastic sheet and subsequently coated with a bonding adhesive.
3) Natural rubber material is mixed in a two roll mill and masticated with a peptizer.
4) The prepared mix of silicon carbide powder along with the adhesive coated on the surface is added to the mill into the natural rubber at a temperature of 25oC.
5) The silicon carbide impregnated rubber composite material is processed further in a calendaring machine into sheets.
6) The silicon carbide impregnated rubber composite sheet is wrapped around a metal mandrel for one layer initially.
7) Further, a layer of fabric material like nylon is wrapped over the initial composite sheet.
8) Further, a galvanized wire of about 1mm is wound over spirally.
9) Further, subsequent layer of natural rubber is wrapped around.
10) Then on, at least one more layer of fabric material, galvanized wire coil and a final layer of rubber is wrapped around.
Example 3:
The silicon carbide reinforced rubber composite was prepared with 50% of silicon carbide powder and 50% of natural rubber and further processed into a flexible rubber hose with steps as in example-2 (from steps 1 to 10)
Example 4:
The silicon carbide reinforced rubber composite was prepared with 40% of silicon carbide powder and 60% of natural rubber and further processed into a flexible rubber hose with steps as in example-2 (from steps 1 to 10)
Example 5:
The silicon carbide reinforced rubber composite was prepared with 30% of silicon carbide powder and 70% of natural rubber and further processed into a flexible rubber hose with steps as in example-2 (from steps 1 to 10)
Example 6:

The silicon carbide reinforced rubber composite was prepared with 25% of silicon carbide powder and 75% of natural rubber and further processed into a flexible rubber hose with steps as in example-2 (from steps 1 to 10)
The various mix composition of the silicon carbide powders and the natural rubber were fabricated into flexible rubber hose with each of the composition providing wear protection for the intended applications. The composition with minimum of silicon carbide (25-30%) and maximum of natural rubber (70-75%) offers considerable weight advantage of about 2kgs from a composition having silicon carbide (60%) and natural rubber (40%).
Example 7
The silicon carbide powders reinforced flexible elastomer hose ia prepared by the method that comprises the steps of -
a. Preparing a mix of silicon carbide powders of two different particle sizes.
b. Coating of the silicon carbide powder with elastomer adhesive solution by
spraying method.
c. Mixing of the elastomer in a two roll-mill for mastication with a peptizer.
d. Mixing of the silicon carbide powder in the mill along with the elastomer.
e. The silicon carbide impregnated elastomer composite material is
processed further in a calendaring machine into sheets.
f. The silicon carbide impregnated elastomer composite sheet is wrapped
around a metal mandrel of certain diameter in plural of layers.
g. Further, a layer of fabric material is wrapped over the initial composite
sheet.
h. Further, a metal wire is wound over spirally.
i. Further, subsequent layer of elastomer is wrapped around.
j. Then on, at least one more layer of fabric material, galvanized wire coil and a final layer of elastomer is wrapped around. The elastomer used inthis method is either a natural rubber or EPDM grade of polymer. The silicon carbide powders has an average diameter of 1000 microns and below, more preferably in the rage of 500 microns to 750 microns. The silicon carbide powder is either black silicon carbide or green silicon carbide and is with purity greater than 98% and more preferably greater than 99%. The peptizer is a pentachlorothiophenol, phenylhydrazine, diphenylsulfides, and xylyl mercaptan. The elastomer adhesive is a rubber or silicone based adhesive. The silicon carbide powders and elastomer are mixed in the ratio 60%: 40%, 50%: 50%, 40%: 60%, 30%: 70% and more preferably in 25%: 75%. The mixing of the silicon carbide powders and elastomer is performed at temperature of 25oC.
The fabric is made from thread material of either a polyester, nylon, glass fibers, aramid fibers laid at an angle 45 to 60 in single or multiple layers depending upon the working pressure. The metal wire used is of a galvanized iron material. The

metal wire is having an average diameter of 5mm and below, more preferably in the range of 1mm and 5mm. The silicon carbide impregnated rubber hose is prepared by this method.

We claim:
1. A method of producing silicon carbide powders reinforced flexible elastomer hose comprising the steps of
a. Preparing a mix of silicon carbide powders of two different particle sizes.
b. Coating of the silicon carbide powder with elastomer adhesive solution
by spraying method.
c. Mixing of the elastomer in a two roll-mill for mastication with a
peptizer.
d. Mixing of the silicon carbide powder in the mill along with the
elastomer.
e. The silicon carbide impregnated elastomer composite material is
processed further in a calendaring machine into sheets.
f. The silicon carbide impregnated elastomer composite sheet is wrapped
around a metal mandrel of certain diameter in plural of layers.
g. Further, a layer of fabric material is wrapped over the initial composite
sheet.
h. Further, a metal wire is wound over spirally.
i. Further, subsequent layer of elastomer is wrapped around. j. Then on, at least one more layer of fabric material, galvanized wire coil and a final layer of elastomer is wrapped around.
2. The method as claimed in claim 1, wherein the elastomer is either a natural rubber or EPDM grade of polymer.
3. The method as claimed in claim 1, wherein the silicon carbide powders has an average diameter of 1000microns and below, more preferably in the rage of 500microns to 750microns.
4. The method as claimed in claim 3, wherein the silicon carbide powder is either black silicon carbide or green silicon carbide.
5. The method as claimed in claim 3, wherein the silicon carbide powders is with purity greater than 98% and more preferably greater than 99%.
6. The method as claimed in claim 1, wherein the peptizer is a pentachlorothiophenol, phenylhydrazine, diphenylsulfides, and xylyl mercaptan.
7. The method as claimed in claim 1, wherein the elastomer adhesive is a rubber or silicone based adhesive.

8. The method as claimed in claim 1, wherein the silicon carbide powders and elastomer are mixed in the ratio 60%: 40%, 50%: 50%, 40%: 60%, 30%: 70% and more preferably in 25%: 75%.
9. The method as claimed in claim 1, wherein the mixing of the silicon carbide powders and elastomer is performed at temperature of 25oC.
10. The method as claimed in claim 1, wherein the fabric is made from thread material of either a polyester, nylon, glass fibers, aramid fibers laid at an angle 45 to 60 in single or multiple layers depending upon the working pressure.
11. The method as claimed in claim 1, wherein the metal wire is a galvanized iron material.
12. The method as claimed in claim 11, wherein the metal wire is having an average diameter of 5mm and below, more preferably in the range of 1mm and 5mm.
13. A silicon carbide impregnated rubber hose by the method as claimed in claim 1.