Study On Formula And Properties Of Heat-resistant V-ribbed Belt

Ethylene propylene diene rubber(EPDM)has excellent heat resistance,flex resistance,oxidation resistance,ozone resistance,and chemical resistance.At the same time,the price of EPDM is relatively low,and it has the smallest specific gravity among all rubbers.After filling a large amount of filler and oil,it can still maintain excellent performance,which can further reduce the product price.In recent years,competition in the automotive industry has intensified,and the situation of cost reduction has become increasingly severe.EPDM has many applications in the automotive industry,including transmission belts and seals.In this paper,in order to pursue lower cost,better heat resistance and wear resistance,the formulation of a new type of V-ribbed belt material was studied.V-ribbed Belt materials are divided into belt back fabric,adhesive,tensile body and wedge rubber.In this paper,EPDM was used as the base material of adhesive and wedge rubber,and the effect of compound formula on the properties of V-ribbed belt materials was studied by orthogonal experiments.In the formulation of the adhesive,resin is added to improve the adhesion between it and the tensile body,wedge rubber,etc.The effects of raw rubber varieties,carbon black N550 content,and sulfur content in the vulcanization system on EPDM adhesives were discussed.In the formulation of wedge rubber,nylon short fibers were added to improve its tensile strength and abrasion properties.The effects of paraffin oil,carbon black N330,nylon short fibers,and sulfur on the properties of EPDM wedge rubber were discussed.In addition,the interactions between paraffin oil and carbon black N330,carbon black N330 and nylon staple fibers were studied.This paper mainly takes the vulcanization speed,hardness(Shore A),permanent deformation,100%elongation strength,tensile strength,elongation at break,dynamic wear resistance and other performance parameters as evaluation indicators,and studies the various factors in the formulation,and compare the properties of the rubber before and after aging to study the heat resistance,to Study the influence of various factors in the formulation on the comprehensive performance of the rubber compound.The orthogonal experiment results of the adhesive show that the type of raw rubber has the greatest impact on the 100%elongation strength,hardness,and tensile strength of the vulcanized rubber.The raw rubber type with a higher Mooney viscosity has better comprehensive properties;The content of carbon black N550 has the largest impact on the elongation at break of vulcanizates,and it also has a greater impact on the tensile strength of vulcanizates.With the increase of carbon black N550 content,the elongation at break of vulcanizates gradually decreases,but the strength gradually increases;the change in the amount of sulfur has a relatively small effect on the comprehensive performance of the vulcanizate.Select EPDM5470Q,fill with 75 parts by mass of carbon black N550,and when the amount of sulfur is 0.7 parts by mass,the comprehensive performance of the adhesive is better,and the comprehensive performance after aging is also maintained at a high value.At this time,the normal vulcanization time T₉₀ of the adhesive is 12?43",the hardness(Shore A)before and after aging is 60 degrees and 69 degrees,the tensile strength is 15.55 MPa and 13.21 MPa,and the elongation at break are 204.94%and 102.68%,the permanent deformation rate is 4.77%and 6.08%,the 100%elongation strength before aging also reached 6.08MPa,at the same time,the storage modulus is 48.67MPa at 25?,and at 120?is 19.08MPa.Due to the influence of short fiber orientation,wedge rubber is divided into L direction rubber which is along the fiber orientation and T direction rubber which is perpendicular to the fiber orientation.The results of orthogonal experiments show that the amount of carbon black N330 has the most influence on the results of various vulcanizates,and the effect of the amount of nylon short fibers is the second.There is an interaction between the amount of paraffin oil and the amount of carbon black N330,the amount of carbon black N330 and the amount of nylon staple fiber,which has a certain effect on the experimental results.The amount of paraffin oil has a large effect on the results of some experiments,and the amount of sulfur has a relatively small effect on the results.Selecting5 parts by mass of paraffin oil,65 parts by mass of carbon black N330,4 parts by mass of nylon staple fiber,and 0.5 parts by mass of sulfur,the wedge rubber has the best overall performance.The 100%elongation strength before aging of the L direction specimen and the tensile strength after aging were higher than those of the T direction specimen,but the elongation at break was lower than that of the T direction samples.At this time,the normal vulcanization time T₉₀ of the wedge rubber is 10?17",the abrasion loss is 7.4%,and the hardness(Shore A)before and after aging is 60 degrees and 70 degrees.The tensile strength of the samples before and after aging are about 18 MPa and 12 MPa,respectively,the elongation at break is about 270%and 120%,the permanent deformation rates are about 2.0%and 4.2%,100%before aging,and the tensile strength is also above 6 MPa,both in the L-direction sample and the T-direction.At the same time,the storage modulus at 25°C is about 80 MPa,and the storage modulus at 120°C is greater than 30 MPa,both in the L-direction sample and the T-direction.