Poly-V belt comprising a layer of thermoplastic material and a knitted fabric embedded in an elastomeric layer
Poly-V belt comprising a body made of elastomeric material, preferably EPDM, a plurality of threadlike resistant inserts longitudinally embedded in the body, and a coupling portion integrally connected to the body and comprising a plurality of V-shaped ribs arranged side by side and alternated with V-shaped grooves. According to the present invention the belt comprises a layer of a thermoplastic material which covers the ribs at least partially, and a layer of elastomeric material in which a knitted fabric is embedded. The layer of elastomeric material is above and in contact with the thermoplastic material.
1. A poly-V belt ( 1 ) comprising a body ( 2 ) comprising a first elastomeric material, a plurality of threadlike resistant inserts ( 3 ) longitudinally embedded in the body, and a coupling portion ( 4 ) integrally connected to the body ( 2 ) and comprising a plurality of V-shaped ribs ( 5 ) arranged side by side and alternated to V-shaped grooves ( 6 ), said belt comprising:
a layer of thermoplastic material ( 8 ) which at least partially covers said ribs ( 5 ) and a layer comprising a second elastomeric material ( 9 ) in which a fabric is immersed ( 10 ), said layer of second elastomeric material being directly in contact with said layer of thermoplastic material ( 8 );
wherein said second elastomeric material is present between the fabric and the first layer of thermoplastic material, thereby preventing contact between the fabric and the thermoplastic material.
2. The belt ( 1 ) according to claim 1 , characterised in that said fabric is selected from the group consisting of woven fabric, knitted fabric and non-woven fabric.
3. The belt ( 1 ) according to claim 1 , characterised in that said first elastomeric material is an ethylene alpha-olefin elastomer.
4. The belt ( 1 ) according to claim 3 , characterised in that said ethylene alpha-olefin elastomer is EPDM.
5. A belt ( 1 ) according to claim 1 , characterized in that said thermoplastic material comprises a polyolefin.
6. A belt ( 1 ) according to claim 1 , characterized in that said thermoplastic material comprises a polyethylene homo or copolymer.
7. The belt ( 1 ) according to claim 6 , characterised in that said polyethylene is selected from the group consisting of LDPE, LLDPE, UHMWDPE or mixtures thereof.
8. The belt ( 1 ) according to claim 6 , characterised in that said thermoplastic material has a thickness in the range between 30 μm and 200 μm.
9. The belt ( 1 ) according to claim 1 , characterised in that said second elastomeric material is an ethylene alpha-olefin elastomer.
10. The belt ( 1 ) according to claim 9 , characterised in that said second elastomeric material is EPDM.
11. The belt ( 1 ) according to claim 1 , characterized in that said layer of second elastomeric material ( 9 ) has a thickness in the range between 100 and 300 μm.
12. The belt ( 1 ) according to claim 1 , characterised in that said knitted fabric has an interlock configuration.
13. The belt ( 1 ) according to claim 1 , characterised in that said knitted fabric has a weight in the range between 50 and 100 g/m 2 .
14. A process for producing a transmission belt according to claim 1 comprising the steps of:
applying said layer of thermoplastic material on a surface of elastomeric material before a vulcanising step;
applying a layer of elastomeric material containing said knitted fabric in direct contact with said layer of thermoplastic material; and
vulcanising under pressure to mould said belt.
15. A poly-V belt comprising:
a body comprising a first elastomeric material, a plurality of threadlike resistant inserts longitudinally embedded in the body, and a coupling portion integrally connected to the body, the coupling portion comprising a plurality of V-shaped ribs arranged side by side and alternated to V-shaped grooves; and
a first layer of thermoplastic material, which at least partially covers said plurality of V-shaped ribs; and
a second layer comprising a second elastomeric material in which a fabric is immersed, said layer of second elastomeric material being directly in contact with said first layer of thermoplastic material;
wherein said second elastomeric material is present as an outermost surface of said plurality of V-shaped ribs;
wherein said second elastomeric material is present between the fabric and the first layer of thermoplastic material, thereby preventing contact between the fabric and the thermoplastic material.