Description:RUBBER CRAWLER WITH GUIDE RUBBER LUG MADE BY CROSSLINKING OR VULCANIZATION OF RUBBER COMPOSITION
BACKGROUND
Technical Field
[0001] The embodiment herein generally relates to rubber crawler and more particularly, to the rubber crawler with a guide rubber lug made by crosslinking or vulcanization of a rubber composition to reduce a heat or a friction generated between the guide lug and a guide wheel. The rubber composition also provides improved fatigue and abrasion resistance.
Description of the Related Art
[0002] An existing guide lug is made of rubber on a sprocket pin to transmit driving power when the guide lug is engaged with a sprocket. A rubber track typically includes several guide lugs produced at regular intervals along the rubber track’s longitudinal axis. Durability of the guide lug may reduce significantly if the drive wheel of a machine body and the guide lug comes in contact with one another, due to the contact between the machine body and the guide lug, as a result of deformation, heat is generated. The stress placed specifically on the root causes the guide lug to bend, easily leading to abrasion or damage. Additionally, the drive wheel's contact and collision with the guide lug results in significant running resistance and substantial energy losses.
[0003] Accordingly, there remains a need for a rubber crawler with a guide rubber lug made by crosslinking or vulcanization of a rubber composition to reduce a heat or a friction generated between the guide lug and a guide wheel. The rubber composition also provides improved fatigue and abrasion resistance.

SUMMARY
[0004] In view of the foregoing, embodiments herein provide a rubber crawler with a guide rubber lug made by crosslinking or vulcanization of a rubber composition. Characterised in that the rubber composition includes at least one of rubber, a silica with silane coupling agent, a carbon black, a recovered carbon, a reclaim rubber, a calcium silicate powder, a liq NBR process aid, and Sulphur to accelerator (S/A) maintained in ratio less than 1. The reclaim rubber is obtained from ground tires The at least one of rubber chosen from styrene butadiene rubber. The styrene butadiene rubber contains a total of 20 to 30% by weight of the rubber, 5 to 20% by weight is the butadiene rubber and 5 to 30% by weight of the natural rubber.
[0005] In some embodiments, the rubber composition is obtained through a process. The process includes mixing, using a intermix, the silica with silane coupling agent, the carbon black, the recovered carbon, the reclaim rubber, the calcium silicate powder, the liquid NBR process aid for 290 seconds at a dump temperature of 140– 150 °C and rotor speed of motor at 30 rpm to obtain a first mixed compound. The process further includes repassing, using the intermix, the first mixed compound for 180 seconds at a dump temperature of 110– 120 °C and rotor speed of motor at 30 rpm to obtain a repassed mixed compound. The process further includes maturing the repassed mixed compound overnight. The process further includes rotating, using the intermix, the repassed mixed compound at RPM 20 and the dump temperature lesser than 110°C to obtain final mixed compound. The process further includes sheeting out, using a two-roll mill, the final mixed compound to obtain the rubber composition.
[0006] In some embodiments, the silica is in quantity of 10-80 parts per hundred (phr).
[0007] In some embodiments, the recovered carbon is in quantity of 5-20 phr.
[0008] In some embodiments, the reclaim rubber in quantity of 5-20 phr.
[0009] In some embodiments, the wollastonite is in quantity of 1-10 phr.
[00010] In some embodiments, the process aid used is liquid NBR with acrylonitrile content less than 28%.
[00011] In some embodiments, the sulphur to accelerator is in a ratio <1.
[00012] In other aspects, the embodiments herein a rubber crawler with a guide rubber lug made by crosslinking or vulcanization of a rubber composition. The rubber composition is obtained through a process. The process includes mixing, using a intermix, the silica with silane coupling agent, the carbon black, the recovered carbon, the reclaim rubber, the calcium silicate powder, the liq NBR process aid for 290 seconds at a dump temperature of 140– 150 °C and rotor speed of motor at 30 rpm to obtain a first mixed compound. The process further includes repassing, using the intermix, the first mixed compound for 180 seconds at a dump temperature of 110– 120 °C and rotor speed of motor at 30 rpm to obtain a repassed mixed compound. The process further includes maturing the repassed mixed compound is overnight. The process further includes rotating, using the intermix, the repassed mixed compound at RPM 20 and the dump temperature lesser than 110°C to obtain final mixed compound. The process further includes sheeting out, using a two-roll mill, the final mixed compound to obtain the rubber composition.
[00013] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF THE DRAWINGS
[00014] The embodiments herein will be better understood from the following detailed description with reference to the drawings, in which:
[00015] FIG. 1 illustrates a rubber crawler, according to some embodiments herein;
[00016] FIG. 2 illustrates components used in obtaining a rubber crawler with a guide rubber lug made by crosslinking or vulcanization of a rubber composition, according to some embodiments herein; and
[00017] FIG. 3 illustrates a process of obtaining a rubber crawler with a guide rubber lug made by crosslinking or vulcanization of a rubber composition, according to some embodiments herein.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[00018] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[00019] As mentioned, there remains a need for the rubber crawler with a guide rubber lug made by crosslinking or vulcanization of a rubber composition to reduce a heat or a friction generated between the guide lug and a guide wheel. The crosslinking or vulcanization is a process by which polymer chains are bonded to one another using suitable crosslinking agents such as Sulphur and accelerators. The rubber composition also provides improved fatigue and abrasion resistance. Referring now to the drawings, and more particularly to FIGS. 1 through 3, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[00020] FIG. 1 illustrates a rubber crawler 100, according to some embodiments herein. The rubber crawler 100 includes a guide lug 102. The rubber crawler 100 with a guide rubber lug 102 is made by crosslinking or vulcanization of a rubber composition.
[00021] FIG. 2 illustrate components used in obtaining the rubber crawler with a guide lug made by crosslinking or vulcanization of a rubber composition, according to some embodiments herein. The rubber composition includes at least one of rubber 202, a silica with silane coupling agent 204, a carbon black 206, a recovered carbon 208, a reclaim rubber 210, a calcium silicate powder 212, a liq NBR process aid 214, and Sulphur to accelerator (S/A) maintained in ratio less than 1. The at least one of rubber chosen from styrene butadiene rubber. The styrene butadiene rubber contains a total of 20 to 30% by weight of the rubber, 5 to 20% by weight is the butadiene rubber, and 5 to 30% by weight of the natural rubber. In some embodiments, the reclaimed rubber 210 is a recycled rubber from ground tires or from rubber vulcanized. The reclaimed rubber 210 is as a superfine reclaim rubber.
[00022] In some embodiments, the rubber composition is obtained through a process. The process includes mixing, using a intermix 216, the silica with silane coupling agent 204, the carbon black 206, the recovered carbon 208, the reclaim rubber 210, the calcium silicate powder 212, the liq NBR process aid 214 for 290 seconds at a dump temperature of 140– 150 °C and rotor speed of motor at 30 rpm to obtain a first mixed compound 218. The process further includes repassing, using the intermix 216, the first mixed compound 220 for 180 seconds at a dump temperature of 110– 120 °C and rotor speed of motor at 30 rpm to obtain a repassed mixed compound 222. The process further includes maturing the repassed mixed compound 222 is overnight. The process further includes rotating, using the intermix 216, the repassed mixed compound 222 at RPM 20 and the dump temperature lesser than 110°C to obtain final mixed compound. 224 The process further includes sheeting out, using a two-roll mill, the final mixed compound 224 to obtain the rubber composition.
[00023] In some embodiments, the silica 202 is in quantity of 10-80 parts per hundred (phr). The carbon black 206. The recovered carbon 208 is in quantity of 5-20 phr. The reclaim rubber 210 in quantity of 5-20 phr. The wollastonite is in quantity of 1-10 phr. The process aid used is liquid NBR 214 with acrylonitrile content less than 28%. The sulphur to accelerator is in a ratio <1. In some embodiments, optimum cure time (OCT) for the compounds were determined by Rubber process analyser (RPA 2000 Alpha Technologies, USA) at 150°C for 30 minutes. The sheets were moulded at 150°C in compression moulding machine.
[00024] In some embodiments, the rubber composition further includes the below materials for the table 1.
Materials Specifications
1 ISNR 20 Masticated Indian standard natural rubber
2 SBR 1502 Cold emulsion SBR 23.5% bound styrene
3 BR Ni catalyst based butadiene rubber
4 RECLIAM RUBBER Superfine powder-Ground tire
5 Liq NBR 28% ACN content
6 Recovered carbon Nitrogen surface area (particle size) =57 m2/g
7 N330 HAF- Nitrogen surface area (particle size) =78 m2/g
8 N550 FEF- N550: Nitrogen surface area (particle size) =40 m2/g
9 PPT.SILICA Surface area-170-190 m2/g
10 Wollastonite Calcium silicate- particle surface area BET 3 m2/g

11 silane( si 69) Silica coupling agent-TESPD- sulphur content 14%
12 PEG POLYETHYLENE GLYCOL (PEG-4000)
13 Ricobond high vinyl butadiene functionalized with maleic anhydride
14 ZINC OXIDE Activator
15 STEARIC ACID fatty acid
16 TDQ Polymerised 1, 2-dihydro-2, 2, 4-tetramethyl quinoline
17 PARAFFIN WAX Process aid
18 ZINCOLET RN44 processing aid
19 Phenolic resin_1068 phenlic(curing resin)
20 6PPD Anti-ageing agent
21 ELASTO SUPREME Aromatic-oil
23 I-SULPHUR Insoluable sulphur
24 CBS cyclo benzyl sulphenamide
25 DPG Di phenyl guanidine
26 PVI Pre vulcanisation inhibitor-CTP cyclo hexyl thio pthalamide
27 DTDM 4,4’-Dithiodimorpholine

28 MBTS mercapto benzo thio sulphenamide
TABLE 1
[00025] In some embodiments, ESBR (Emulsion Styrene Butadiene Rubber) 1502 with 23.5% styrene was used. Referring to the table 1, the rubber graded based on Indian standard was procured- ISNR 20 with specifications of dirt content 0.20 percent max, volatile matter 0.8 percent max and ash 1 per cent max was used in the rubber composition. Further the rubber composition included Nickel catalysed butadiene rubber.
[00026] The carbon black 206 is a carbon black of N550: Nitrogen surface area (particle size) =40 m2/g, DBP (particle structure): particle size: 121 m3/g, Iodine absorption number (surface area) = 43g/kg. The carbon black 206 can also be carbon black of N330: Nitrogen surface area (particle size) =78 m2/g, DBP (particle structure): particle size: 102 m3/g, Iodine absorption number (surface area) = 82g/kg. The recovered carbon black 210 is a Nitrogen surface area (particle size) =57 m2/g, DBP (particle structure): particle size: 102 m3/g, Iodine absorption number (surface area) = 82g/kg. The Silica 204 is taken in particle surface of 170-190 m2/g, the Silane coupling agent (TESPD) with sulphur content 14.40. Additives ZnO, Stearic acid, Sulphur and CBS consumed.
[00027] For example, consider the rubber composition obtained using a sample taken as shown in table 1, the table 1 includes five sets of varying carbon black content formulation. For example the samples are designated as Ex, R, K1, k2, K3, K4. The Ex stands for controlled sample. R stands for regular, K1 stands for example 1, K2 stands for example 2, K3 stands for example 3, and K4 stands for example 4.
Ex R K1 K2 K3 K4
1 ISNR 20 Masticated 80 60 50 60 50 50
2 SBR 1502 20 35 30 15 30 20
3 BR 20 25 20 30
4 RECLIAM RUBBER 10 10 10 10 5
5 Liq NBR 2
6 Recovered carbon 10
7 N330 50 60 15 15 30
8 N550 15 5
9 PPT.SILICA 12 15 55 45 70 30
10 Wollastonite 5
11 silane( si 69) 2.75 2.25 3.5 0.8
12 PEG 1.5 1.5 1.5 1.5 1
13 Ricobond 0.5
14 ZINC OXIDE 5 5 4 4 4 4
15 STEARIC ACID 2 2 2 2 2 2
16 TDQ 3 2.5 1.5 1.5 1.5 1.5
17 PARAFFIN WAX 1 1.5 1.5 1.5 1.5 1
18 ZINCOLET RN44 1 1 2 2 2 1
19 phenolic resin 1.5 1.5 1.5 2
20 6PPD 1.5 1.5 1.5 1.5 1.5 1.5
21 ELASTO SUPREME 4 5 4 4 6 2
23 I-SULPHUR 1.7 1.6 1.5 1.5 1.5 1.4
24 CBS 0.89 0.9 1.2 1.2 1.2 1.5
25 DPG 0.8 0.8 0.8 0.3
26 PVI 0.2 0.2 0.3
27 DTDM 0.4 0.4 0.5
28 MBTS 0.36 0.3
TOTAL 183.0 203.4 205.75 210.25 213.5 203.3

TABLE 2
[00028] In some embodiments, using the sampled rubber composition, a physical characteristic of the rubber composition was tested. The physical characteristics test includes hardness, tensile, Dynamic Mechanical Analysis (DMA), Abrasion resistance, Demattia: Flex tester, and Rubber Process Analyser.
[00029] The hardness of each sample was measured by Shore A Durometer as per ASTM D 2240-05 test method. The average of four observations have been taken.
[00030] In the Tensile test, a dumbbell shaped specimen was punched out from the moulded sheets by Hollow Die Punch (Type c). The tensile test was carried out in a Universal Testing Machine (Instron) across head speed of 500mm/min 25±2°C. Tensile and tear tests were carried out as per the ASTM D 412-98 respectively. Results of tensile for each sample was noted down.
[00031] The DMA of the samples was performed by using a Dynamic Mechanical Analyzer-DMA VA 4000, (Metravib) Temperature sweep was done in tension mode at constant strain 0.25% and frequency 10 Hz. The temperature is + 70°C for cured samples. The storage modulus (E'), loss modulus (E'') and tand values were measured as a function of temperature under the tension mode.
[00032] A DIN abrasion tester was employed to determine weight loss of abraded rubber vulcanizates. DIN abrader as per ISO 4649 (ASTM D5963). Flexing at 300 cycles per min, samples are employed till crack was initiated.
[00033] The RPA of the samples was performed by using RPA2000, Temperature at 100 °C was done in strain 5% and frequency 10 Hz. The storage modulus (E'), loss modulus (E'') and tand values were measured as a function of temperature. The below table 3 and table 4 provides exact results obtained during each test performed on the rubber crawler.
S.No Parameter Unit Ex R K1 K2 K3 K4
1 Hardness Shore A 65 69 72 70 73 75
2 Tensile strength M pa 16 16 19 18 19 17
3 Toughness 7098 9920 14060 12060 13870 10030
4 Tear Strength N/mm 54 80 90 98 99 90
ABRASION
Ex R K1 K2 K3 K4
5 ABRASION LOSS mm3 189 168 153 160 136 150
FLEX FATIGUE TEST
Ex R K1 K2 K3 K4
6 Crack Initiation Avrg
(cycles) >1,00000 cycles 1,00,00 NO crack till 2,05,000 1,68,000
RPA EX R K1 K2 K3 K4
7 Tan delta 0.287 0.263 0.161 0.176 0.144 0.178
DMA EX R K1 K2 K3 K4
8 Tan delta 0.2 0.237 0.163 0.159 0.152 0.158
9 E' 7.02 8.97 9.37 9.44 10.6 9.2
10 E'' 1.40 2.13 1.53 1.50 1.62 1.45
11 J’’ 0.0029 0.0025 0.0017 0.00164 0.0014 0.0016
TABLE 3
Cure system EX R K1 K2 K3 K4
S/A- ratio 0.92 0.89 0.75 0.75 0.75 0.54
TABLE 4
[00034] The Silica -silane (Silanisation) reduces heat produced due to the friction between the rubber crawler and track. The wollastonite improves the stiffness of the rubber crawler. The recovered carbon and the reclaim provides sustainability to the rubber crawler. The method of obtaining the rubber crawler provides fatigue and heat improvement.
[00035] The rubber composition reduces the heat or the friction generated between the guide lug and the guide wheel. The rubber composition has superior abrasion resistance, resistance to crack growth and reduced heat generation caused due to the friction between guide wheel and contact surface of rubber. The rubber composition also reduces the carbon footprint. Referring to table 3 and table 4 shows that the rubber crawler provides reduced heat generation (Tan delta, E’’). The rubber crawler is excellent abrasion resistance (Abrasion resistance). The rubber crawler provides improved cut and crack growth resistance (Flex property, Toughness, cure system). The rubber crawler provides Hysteresis-(Tan delta, cure system). The rubber crawler is sustainable (due to recovered carbon, reclaim rubber). The rubber composition has improved efficiency.
[00036] FIG. 2 illustrates a process 300 of obtaining a rubber crawler with a guide rubber lug made by crosslinking or vulcanization of a rubber composition, according to some embodiments herein. At step 302, the process 300 includes mixing, using a intermix 216, the silica 204 with silane coupling agent, the carbon black 206, the recovered carbon 208, the reclaim rubber 210, the calcium silicate powder 212, the liq NBR process aid 214 for 290 seconds at a dump temperature of 140– 150 °C and rotor speed of motor at 30 rpm to obtain a first mixed compound 218. St step 304, the process 300 further includes repassing, using the intermix 216, the first mixed compound 218 for 180 seconds at a dump temperature of 110– 120 °C and rotor speed of motor at 30 rpm to obtain a repassed mixed compound 220. At step 306, the process 300 further includes maturing the repassed mixed compound 220 is overnight. At step 308, the process 300 further includes rotating, using the intermix 216, the repassed mixed compound 220 and sulphur at RPM 20 and the dump temperature lesser than 110°C to obtain final mixed compound 222. At step 310, the process 300 further includes sheeting out 224, using a two-roll mill, the final mixed compound 222 to obtain the rubber composition
[00037] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope.
, C , Claims:We claim:
1. A rubber crawler (100) with a guide rubber lug (102) made by crosslinking or vulcanization of a rubber composition, wherein characterised in that the rubber composition comprising:
at least one of rubber (202) chosen from styrene butadiene rubber, wherein the styrene butadiene rubber contains a total of 20 to 30% by weight of the rubber, 5 to 20% by weight is the butadiene rubber, and 5 to 30% by weight of the natural rubber;
a silica with silane coupling agent (204);
a carbon black (206);
a recovered carbon (208);
a reclaim rubber (210), wherein the reclaim rubber (210) is obtained from ground tires;
a calcium silicate powder (212);
a liq NBR process aid (214); and
Sulphur to accelerator (S/A) maintained in ratio less than 1.
2. The rubber crawler (100) as claimed in claim 1, wherein the rubber composition is obtained through a process, the process comprises:
mixing, using a intermix (216), the silica (204) with silane coupling agent, the carbon black (206), the recovered carbon (208), the reclaim rubber (210), the calcium silicate powder (212), the liq NBR process aid (214) for 290 seconds at a dump temperature of 140– 150 °C and rotor speed of motor at 30 rpm to obtain a first mixed compound (218);
repassing, using the intermix (216), the first mixed compound (218) for 180 seconds at a dump temperature of 110– 120 °C and rotor speed of motor at 30 rpm to obtain a repassed mixed compound (220);
maturing the repassed mixed compound (220) is overnight;
rotating, using the intermix (216), the repassed mixed compound (220) and the sulphur at RPM 20 and the dump temperature lesser than 110°C to obtain final mixed compound (222); and
sheeting out (224), using a two-roll mill, the final mixed compound (222) to obtain the rubber composition.
3. The rubber crawler (100) as claimed in claim 1, wherein the silica (204) is in quantity of 10-80 parts per hundred (phr).
4. The composition as claimed in claim 1, wherein the recovered carbon (208) is in quantity of 5-20 phr.
5. The rubber crawler (100) as claimed in claim 1, wherein the reclaim rubber (210) in quantity of 5-20 phr.
6. The rubber crawler (100) as claimed in claim 1, wherein the wollastonite is in quantity of 1-10 phr
7. The rubber crawler (100) as claimed in 1, wherein the process aid used is liquid NBR with acrylonitrile content less than 28%
8. The rubber crawler (100) as claimed in 1, wherein the sulphur to accelerator is in a ratio <1.
9. The rubber crawler (100) with a guide rubber lug made by crosslinking or vulcanization of a rubber composition, wherein the rubber composition is obtained through a process, the process comprises:
mixing, using a intermix (216), the silica (204) with silane coupling agent, the carbon black (206), the recovered carbon (208), the reclaim rubber (210), the calcium silicate powder (212), the liq NBR process aid (214) for 290 seconds at a dump temperature of 140– 150 °C and rotor speed of motor at 30 rpm to obtain a first mixed compound (218);
repassing, using the intermix (216), the first mixed compound (218) for 180 seconds at a dump temperature of 110– 120 °C and rotor speed of motor at 30 rpm to obtain a repassed mixed compound (220);
maturing the repassed mixed compound (220) is overnight;
rotating, using the intermix (216), the repassed mixed compound (220) and the sulphur at RPM 20 and the dump temperature lesser than 110°C to obtain final mixed compound (222); and
sheeting out (224), using a two-roll mill, the final mixed compound (222) to obtain the rubber composition.