Study of Rubber Adhesive Compounds for Tire Retreading: Drying Rate and Adhesion Strength

  ISSN : 2477-3298 Prosiding Seminar Nasional Kulit, Karet dan Plastik ke-6 Yogyakarta, 25 Oktober 2017

  

Study of Rubber Adhesive Compounds for Tire Retreading: Drying Rate and

Adhesion Strength

_{1,* 1 1} Ike Setyorini , Herminiwati

Center for Leather, Rubber and Plastics, Jl. Sokonandi No. 9 Yogyakarta, 55166, Indonesia

• *Corresponding author. Telp.:+62 274 512929, 563939, Fax.: +62 274 563655

  E-mail: ike-setyorini@kemenperin.go.id

  

ABSTRACT

The scope of this article istostudy the drying rate and the adhesion strength of

rubberadhesive compounds that used three different tackifiers i.e. Coumaron Resin, Siongka, and

  

Koresin. The rubber adhesive compounds were diluted in n-Hexane with the content of rubber

adhesion compounds was 12 %, 13 %, 14 %, and 15 %. And then it was spread on the surface of

2,5 x 15 cm testpiece of the casing (worn tire)and retreading tire compounds.A time until the

adhesive is slightly dry was used to determine the drying rate. The test piece of casing and

o

retreading tire compounds was taped in one piece and pressed at 170 . The adhesion strength was

tested according to JIS K6301.The results showthat thebestrubber adhesive is an adhesive that uses

Siongka as the tackifier with thesolid content of 14%, adhesion strength

  2 4.15kg/cm,weight13.653mg/cm and drying time 5 minutes.

  Keywords: rubber adhesive, tackifier , motorcycle tires, retreading 103

  ISSN : 2477-3298 Prosiding Seminar Nasional Kulit, Karet, dan Plastik ke-6

  Yogyakarta, 25 Oktober 2017

  INTRODUCTION

  The adhesive is a material that is capable to stick fast to surface or object. There is a large number of adhesive types for various aplication. One of the applications of adhesive is in tire vulcanized elastomers to themselves and to other materials is generally accomplished using an adhesive derived from an elastomer similar to the one being bonded. Natural rubber is one of the rubber-based materials that is used as adhesive (Ebnesajjad, 2011; Rippel & Galembeck, 2009).

  The adhesive composition that is applied in tire retreading is a thermoset adhesive.

  

Thermoset adhesive is crosslinked by polymeric resins that are cured using heat and/or heat and

pressure. Rubber based adhesives may contain a wide variety of component materials such as

  elastomers, resins, tackifiers, fillers, plasticizers and softeners, antioxidants, curing agents, etc (Khan & Poh, 2011). The adhesive comprises a rubber composition containing a sulfur curative together with carbon black, processing oil, and tackifier resin (US Patent, 2000). Tackifiers are chemical compounds used in formulating adhesives to increase the tack, the stickiness of the surface of the adhesive. The tackifier acts as a diluent to develop the flowability of the and improves the peel strength (Sasaki et al., 2008). Tackifiers used are usually resins. Tackifiying resin that was usually usedcan be divided in three groups: hydrocarbon resins, rosin resins, and phenolic resins. Coumarone-indene resin is one of hydrocarbon resins. Coumarone-indene resin was used as the tackifier of a natural rubber

• –based press- are-sensitive adhesive. The viscosity and tack of the adhesive is affected by resin content due to the concentration effect of tackifier resin (Poh & Chee, 2007). Hydrocarbon tackifier and rosin tackifier were applied in epoxidize natural rubber latex- based pressure sensitive adhesive. Hydrocarbon tackifier lower viscosity as a result of increased repulsion between particles as compared to rosin ester tackifier. The peel adhesion of adhesive containing hydrocarbon tackifier was greater than adhesive containing rosin ester tackifier (Rohani et al., 2013). Koresin is aphenolic resin that was applied to provide tack of rubber compounds during the building process of green tires until they are vulcanized(Durairaj, 2013).

  This paper studied the properties of rubber adhesive compounds for tire retreading that used three different tackifiers i.e. Coumaron Resin, Siongka, and Koresin. Coumaron resin representative hydrocarbon tackifier resin, Siongka representative rosin tackifier resin from pine trees, and Koresin representative phenolic tackifier resin. The adhesive compounds were diluted in solvent for several concentration. The drying rate and the adhesion strength of rubber adhesive were investigated.

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  ISSN : 2477-3298 Prosiding Seminar Nasional Kulit, Karet dan Plastik ke-6 Yogyakarta, 25 Oktober 2017 MATERIALS AND METHODS Materials

  Suitable worn tires were used in this study as the casing that is glued together with tire (RSS1). The additives materials used were zinc oxide (ZnO) Indoxide, actiplast 8, stearic acid Aflux 42M, Carbon Black N660, insoluble sulfur, vulkanox HS, Coumaron Resin (C), Siongka (S), Koresin (K), Vulkacit DM/C, and n-hexane.

  Methods Compounding

  Rubber adhesive compound’s preparation was made with the composition and formulation that are presented in Table 1.

  

Table 1. Formulation of rubber adhesive compound

Materials C S K

Smoked sheets 100 100 100

  Actiplast 8 0,5 0,5 0,5 Zinc oxide

  30

  30

  30 Stearic acid 0,5 0,5 0,5 Vulkanox HS

  1

  1

  1 N 660 (GPF) black

  30

  30

  30 Vulkacit DM/C 1,2 1,2 1,2 Sulphur (insoluble)

  4

  4

  4

  6 - - Coumaron Resin

• Siongka

  6 - Koresin

• 6 -

  Preparation of Rubber Adhesive

  Rubber adhesive compound was diluted in n-hexane with the content of compound are presented in Table 2.

  

Table 2. Formulation of rubber adhesive

Rubber Adhesive Compound Content of Compound (%)

  12

  13

  14

  15 C C12 C13 C14 C15 S S12 S13 S14 S15 K K12 K13 K14 K15 105

  

ISSN : 2477-3298 Prosiding Seminar Nasional Kulit, Karet, dan Plastik ke-6

Yogyakarta, 25 Oktober 2017

  Bonding Process

  Rubber adhesive compounds were diluted in n-hexane. Then, the rubber adhesive was spread on the surface of 2,5 x 15 cm testpiece of casing and tire retreading compound. Allow the drying time and the amount of the rubber adhesive that is spreaded on the surface of the testpiece.

  Adhesion Testing

  The testpiece of casing and tire retreading compounds which have been spreaded with

  o

  rubber adhesive was taped in one piece and pressed in hot vulcanizing press at 170

  C. Then, the testpiece placed in the conditioning room for 24 hours. Adhesion testing of testpiece according to JIS K6301.

RESULT AND DISCUSSION

  Figure 1. shows the drying time of rubber adhesive solution that spread on casing and tire retreading compound.

  Coumaron Resin Siongka Koresin te u in ,m e tim g n yi Dr Adhesive compound content, %

  

Figure 1. The drying time of rubber adhesive

  The drying time of rubber adhesive is affected by the amount of rubber adhesive content in the solvent. Figure 1 shows that the greater adhesive compound content, the faster the drying time. This is because the greater adhesive compound content has less amount of solvent so that it takes less time to evaporate. In tire retreading manufacturing, drying time of rubber adhesive is related to the efficiency process.

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  Figure 2. shows the weight of rubber adhesive dilution per unit area of casing and tire retreading compound.

  

Figure 2. The weight of rubber adhesive per unit area

  Figure 2 shows that each type of tackifier shows tendency that the greater of solids, the greater the weight of rubber adhesive per unit area. The weight of rubber adhesive per unit area is related to adhesive viscosity. In tire retreading process, the solvent is use to reduce the viscosity of rubber adhesive so that they can be applied in the tire smoothly and spreads uniformly (Kumar, 2016). The thick rubber adhesive is difficult to spread on the surface of casing and tire retreading compound. So, the rubber adhesive does not spread evenly on the surface. Rubber adhesive that is too thick is easy to peel because rubber adhesive is only bonded to one side (casing or tire retreading compound). Otherwise, rubber adhesive that is too thin contains a small rubber adhesive compound, so the adhesion strength is small.

  

Figure 3. Adhesion strength of rubber adhesive

W ei g h t p er u n it ar ea, m g /c m Adhesive compound content, %

  Coumaron Resin Siongka

  A d e si o n Str e n g th , k g /c m Adhesive Compound Content, % Coumaron Siongka Koresin

  ISSN : 2477-3298 Prosiding Seminar Nasional Kulit, Karet, dan Plastik ke-6

  Yogyakarta, 25 Oktober 2017

  Figure 3 shows the adhesion strength of rubber adhesive that bond casing and tire retreading compound. Figure 3 shows that tackifier and adhesive compound content give effect in adhesion strength. Siongka as tackifier at various adhesive content has a relatively higher in adhesion is more compatible with natural rubber as the raw material of adhesive compound. It is similar to the natural resins isolated from the coagulated latex of E. caducifolia, that improving tack strength properties in the filled NR compound comparable to CI resin at equal loading.

  CONCLUSION

  Coumaron resin, Siongka, and Koresin were used as the tackifier in rubber adhesive compounds. The drying time of rubber adhesive is affected by the amount of rubber adhesive content in the solvent. The adhesion strength is affected by adhesive compound content and tackifier that used in rubber adhesive compounds. Siongka as tackifier has a relatively higher adhesion strength than Coumarone resin and Koresin. This is probably because Siongka as a natural tackifier is more compatible with natural rubber adhesive.

  ACKNOWLEDGEMENTS

  The author thank to the Center for Leather, Rubber, and Plastics for the facilities and funding in this study.

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