CARDINALI BRUNO (IT)
| WO2003095538A1 | 2003-11-20 |
| EP1375197A1 | 2004-01-02 | |||
| US3915774A | 1975-10-28 | |||
| EP1241219A1 | 2002-09-18 | |||
| GB2013143A | 1979-08-08 | |||
| US5753365A | 1998-05-19 | |||
| EP1449868A1 | 2004-08-25 | |||
| US5840632A | 1998-11-24 | |||
| EP0441552A2 | 1991-08-14 | |||
| US20010042580A1 | 2001-11-22 |
Claims
1) Insert designed to completely fill the inner tube of tyres for bicycles, motorcycles and light vehicles, characterised in that it is made of thermoplastic materials.
2) Insert as defined in claim 1 , characterised in that the thermoplastic element of the said thermoplastic materials is an elastomer or mixtures of elastomers.
3) Insert as defined in claim 2, characterised in that the said elastomer is composed of syndiotactic polybutadiene 1-2, with tacticity higher than 80%. 4) ' lnsert as defined in claim 3, characterised in that the concentration of syndiotactic polybutadiene 1-2 ranges from 10 to 90%.
5) Insert as defined in claim 2, characterised in that the said elastomer is composed of block copolymers of SBS, SIS, SEBS, SEPS, and EP type.
6) Insert as defined in claim 5, characterised in that the said elastomer is composed of SBS, SIS, SEBS, SEPS and EP with concentration ranging from 0 to 60%.
7) Insert as defined in claim 2, characterised in that the said elastomer is a mixture of the materials mentioned in claims 3 and 5.
8) Insert as defined in any of the preceding claims, characterised in that a plasticizer consisting in a mineral paraffin oil with concentration ranging from 0 and 40% is added to the thermoplastic materials.
9) Insert as defined in any of the preceding claims, characterised in that the said elastomer is hardened with polyethylene (LDPE, LLDPE, VLDPE, HDPE), copolymers and/or ethylene-vinyl acetate (EVA) and/or isotactic polypropylene and/or crystal or anti-shock polystyrene or other compatible hardeners with concentration from 0 to 50%.
10) Insert as defined in any of the preceding claims, characterised in that a micro-cellular expanding agent, composed of a thermoplastic polymer membrane, containing a swelling agent, generally a low molecular weight hydrocarbon, capable of producing gas in extrusion or moulding conditions, forming a microsphere with dimensions from 20 to 300 microns, is added to the said elastomer.
11) Insert as defined in claim 10, characterised in that the said expander comprises an agent, in master or powder form, that can expand in the temperature range suitable to material extrusion or moulding, it being provided that the expander has a concentration ranging from 0 to 20%.
12) Insert as defined in claim 10, characterised in that the expander is a chemical product that decomposes in working conditions, generating gases that remain trapped in the finished product, thus reducing the product density. 13) Insert as defined in claim 10, characterised in that the said expander is a mixture of the expanders mentioned in claims 11 and 12. 14) Insert as defined in claim 1 , characterised in that the said thermoplastic material is combined with a reticulating agent during production, to originate a completely or partially vulcanized product, in normal working conditions. 15) Insert as defined in claim 14, characterised in that the said agent is of radicalic nature also in combination with vinyl xylan aids of known type.
16) Insert as defined in the preceding claims, characterised in that it is composed of a compound with hardness 70 shore A, with the following composition: - 100 parts of syndiotactic polybutadiene 1-2 (type RB 830 by Japan
Synthetic Rubber, or equivalent).
-10 parts of LLDPE (type LL 6201 XR by EXXON Mobil, or equivalent).
-25 parts of SEBS (type KG 1652 by KRATON, or equivalent)
- 15 parts of plastifying oil (Celtis 902 by AGIP or equivalent). - 7 part of micro-cellular master (092 MB 120 by AKZO Nobel or equivalent, including in powder form).
17) Insert as defined in claims 1 to 15, characterised in that it is composed of two layers:
High hardness layer, to be positioned in the area adjacent to the rim. -100 parts of syndiotactic polybutadiene 1 -2 (type RB 840 by JSR). -20 parts of LLDPE. -20 parts of SEBS type KG 1652 (KRATON). -20 parts of mineral oil type Celtis 902.
-7 parts of micro-cellular expanding agent.
Hardness of expanded material is 70 shore A
Low hardness layer placed in contact with tyre and adjacent to ground. -25 parts of syndiotactic polybutadiene 1-2.
-45 parts of SBS (type 161 B by Polimeri Europa or equivalent).
-50 parts of SEBS type KG1652.
-80 parts of mineral oil type Celtis 902 (AGIP or equivalent).
-4 parts of micro-cellular expanding master, only when an expanded product is desired.
Hardness 40 shore A. |
Thermoplastic moulded insert designed to completely fill the inner tube of tyres for bicycles, motorcycles and light vehicles.
The present patent application refers to a thermoplastic moulded insert designed to completely fill the inner tube of tyres for bicycles, motorcycles and light vehicles.
The said insert may be configured as a bar or loop with suitable dimensions.
Scientific literature refers to the fabrication of more or less elastic materials used in bicycles, motorcycles and vehicles in general, to replace the inner tube or the inner tube-tyre system, thus eliminating the risk of punctures, explosions or other similar inconveniences. These materials are produced by extrusion or injection and offered with different lengths and cross-sections, for instance cylindrical, oval, trapezoidal, etc. (the cylindrical cross-section being the most used one), obtained from extrusion of vulcanized and suitably expanded elastomers.
The most used elastomers are derived from natural rubbers or synthetic rubbers based on styrene butadiene copolymers SBr, ethylene- propylene-diene terpolymers EPDM (i.e. cyclopentadiene, dicyclopentadiene, ethenedyl norbomene etc.), ethylene-propylene copolymers EP, polyisoprene NR, polycloroprene, butene diene copolymers (isoprene or other dienic monomer) and other vulcanizable polymers in general. These products have not been successful on the market due to a series of reasons and inconveniences related to the industrial productions of the bars used in replacement of tyre inner tubes. In fact, extrusion, vulcanization and expansion of elastomers is a delicate operation due to difficulties in obtaining the correct level of hardness, density and constant characteristics, in addition to use at low temperatures.
In addition to the aforementioned difficulties in the production of expanded reticular materials, it is almost impossible to obtain combinations of
materials with different characteristics in terms of hardness, spring back and density in order to obtain the desired results with regards to performance and comfort.
Moreover, combinations between layers of vulcanized materials with layers of thermoplastic materials are very difficult and the use of adhesives has not solved the said problems.
Last, but not least, waste materials are not recycled during production or at the end of the product life cycle.
In order to overcome the aforementioned disadvantages, including the combination of different materials, a system has been devised and implemented, being exclusively based on a set of thermoplastic materials, easy to reticulate (if necessary for specific applications), capable of satisfying all the production requirements of low density products used to replace the inner tube of bicycles, motorcycles and light vehicles in general. For some applications, a single compound may be sufficient to solve the problem, however in general the combination of different materials, provided with specific characteristics in terms of softness, spring back, at high and low temperatures, permits to obtain products with excellent performances also in terms of comfort and dimensional invariance. The compounds of the present invention are based on the use of syndiotactic polybutadiene 1-2 homopolymer, in conjunction with block copolymers SBS, SIS, SEBS, SEPS etc., being plasticized and hardened, if necessary with polyethylene, of any type, LDPE, HDPE, LLDPE, VLDPE etc. or with polypropylene, polystyrene, both crystal and anti-shock or other compatible hardeners, such as EVA, EMA, EBA and similar products.
The compound is expanded with special swelling agents of micro- cellular type, which reduce product density to the desired weight levels and ensure suitable resistance to compression and deformation beyond 60° C use temperature. The swelling agents may be a chemical product that decomposes in working conditions, generating gases that remain trapped in the finished product, thus reducing its density.
These products may decompose with esothermal process (i.e. AZDC, azodicarbonamide) or endothermal process (i.e. citric acid or tartaric acid and sodium bicarbonate) in suitable concentration to achieve the desired density.
These compounds can be produced and used for applications designed for use of a single body, that is to say not requiring the aid of other soft components to be stratified during moulding.
In any case, and in general, a base compound, with medium high hardness (higher than 60 shore A), can be associated by stratification with materials having lower hardness and higher spring back properties, which confer elasticity properties that are complementary to the base material. EXAMPLE 1
Compound with 70 shore A hardness, used as single component in integral replacement of inner tube
♦ 100 parts of syndiotactict polybutadiene 1-2 (RB
830 by Japan Synthetic Rubber or equivalent).
♦ 10 parts of LLDPE (LL 6201 XR by EXXON Mobil or equivalent).
♦ 25 parts of SEBS (KG 1652 by KRATON or equivalent)
♦ 15 parts of plastifying oil (Celtis 902 by AGIP or equivalent).
♦ 7 part of micro-cellular master (092 MB 120 by AKZO Nobel or equivalent, including in powder form).
The material extruded at 160° C at 5 m/min speed has the following characteristics: density 0.4 g/cm 3 , hardness of expanded material 65 shore A, compression set at 60724 h, 50%. EXAMPLE 2 Combination of two layers of materials suitable for fabrication of products used to replace inner tubes. High hardness layer placed in the area adjacent to the rim.
♦ -100 parts of syndiotactict polybutadiene 1-2 (type RB 840 by JSR). ♦ -20 parts of LLDPE.
♦ -20 parts of SEBS type KG 1652 (KRATON).
♦ -20 parts of mineral oil type Celtis 902.
♦ -7 parts of micro-cellular expanding agent. Hardness of expanded material is 70 shore A
Low hardness layer placed in contact with tyre and adjacent to ground. ♦ 25 parts of syndiotactic polybutadiene 1-2.
♦ 45 parts of SBS (type 161 B by Polimeri Europa or equivalent).
♦ 50 parts of SEBS type KG1652.
♦ 80 parts of mineral oil type Celtis 902 (AGIP or equivalent).
♦ 4 parts of micro-cellular expanding master, only when an expanded product is desired.
Hardness 40 shore A.
The combination of the two materials is obtained by extrusion at 160° C, 5 m/min speed.
Density 0.40 g/cm3, compression set at 60724 h, 40%. Finally, the said thermoplastic material may be combined with a reticulating agent during production, to originate a completely or partially vulcanized product, in normal working conditions.
The crosslinking agent is of radicalic type, like dicumilperoxide, also in combination with a family of well known vinyl silane derivatives.