Films | Flexibles | Bags
Films | Flexibles | Bags Bioplastics help natural rubber Application of bioplastics in Thailand’s natural rubber plantations Typical rubber nursery that uses polyethylene bags. Natural rubber latex is obtained by tapping of rubber trees called pará rubber. Car tyres are the biggest natural rubber product. They are today made from a compounding of natural rubber with synthetic rubber. Synthetic rubber is petroleum-based similar to petroleum-based plastic, while natural rubber is a biobased product. Thailand supplies 37 % of the 12 million tonnes annually of the world’s natural rubber and therefore has the single biggest market share. Thailand currently grows 1.5 billion rubber trees. Each year 90 million new rubber trees are replanted to replace old trees whose service lives are finished. Plastics are used in every stage of the natural rubber industry, starting from the production of young rubber trees in nurseries where plastics are used for bud grafting, planting bags and netting. When young rubber trees are transferred for planting in larger plantations, plastics are used for ground cover or mulch film, and latex collection cups. After harvesting plastics are used as rubber block wrappers for transportation. Polyethylene and polypropylene are the most widely used plastics in the rubber industry. Maxrich Co., Ltd. is a Thai company that develops technology and products in bioplastics. The company has R&D and manufacturing facilities for compounding and converting of bioplastics. Maxrich’s business includes various applications of bioplastics, among which is the application of bioplastics in the rubber industry. For applications in the rubber industry, Maxrich has been working with the Office of the Rubber Replanting Aid Fund (ORRAF), a state enterprise under the Ministry of Agriculture and Cooperatives. ORRAF provide funds to rubber farmers for replanting. Thus ORRAF and Maxrich have a mutual goal to replace petroleum-based plastics used in the rubber industry with bioplastics. The two parties cooperate to develop bioplastics products that will replace polyethylene and polypropylene. The bioplastics applications in natural rubber have been field tested in actual plantation conditions. Some applications are as follow: Bioplastics planting bags replace polyethylene bags Rubber trees are planted from bud-grafted root stocks which have to be raised in nurseries for 6-12 months before transferring into the ground. The traditional method is to raise the bud-grafted root stocks in polyethylene bags. When the root stocks are planted into the ground farmers cut open the polyethylene bags. This process causes high mortality rate to the root stocks due to damage to the root system. Also, the polyethylene bags become litter in rubber plantations. Polyethylene bags are not only environmentally hazardous but also obstruct the natural flow of rain water. The bud-grafted root stocks come from special clones and hence are highly priced. Maxrich and ORRAF have jointly developed planting bags from bioplastics such that the bags can be planted into the ground with the root stocks. There is no need to cut the bioplastics bags because they will degrade in soil allowing the roots to grow outside of the bags. Other advantages are that 12 bioplastics MAGAZINE [06/14] Vol. 9
Films | Flexibles | Bags while they are slowly degrading they keep the moisture inside. The moisture supplements the rain during temporary rain breaks and so ensuring a higher survival rate. The bioplastics bags also save fertilizer which is normally washed away by rain. Although the material cost of bioplastics bags is higher than that of the conventional polyethylene bags the benefits of bioplastics bags far outweigh the material cost increase. An economics comparison reveals that the benefits of bioplastics bags are worth more than 30 times the increment in material costs. Also, because rubber farmers get a subsidy from ORRAF for replanting, the increase in material costs qualify for ORRAF’s subsidy. In turn ORRAF will benefit from a better environment, better plantation management and an economic pay-back from lower rubber tree mortality. Maxrich and ORRAF have done several field tests using bags compounded from either PLA or PBS. The tests were conducted in different geographical areas, in different soil and temperature conditions. The field tests and growth monitoring draw the above conclusions. From this stage Maxrich and ORRAF are planning to expand the implementation to cover all of Thailand. It is estimated that a few thousand tons of bioplastics will be used to implement the change. Similar ideas can also be applied to other economics crops such as oil palms, fruit orchards and high value teaks. Root trainers for rubber planting A root trainer is a plastic tube used for raising root stock in nurseries for the same purpose as that of planting bags. Planting rubber by root trainers is a new agricultural technology which increases latex productivity and extends the service life of rubber trees. By planting in root trainers the rubber tree’s root system can go deeper into the ground, hence higher latex yield and stronger resistance to typhoons and heavy storms are obtained. Root trainers are now made by the injection moulding of polypropylene which does not degrade in soil. Similar to PE planting bags, they have to be removed before transferring rubber trees into the ground. Maxrich is developing Bio Root Trainers by compounding of biodegradable bioplastics for the injection moulding process. The benefits of Bio Root Trainers mean a better environment and economic savings from higher survival rates. Transportation over long distance by plane to neighbouring countries can also be done with root trainers. Mulch film for rubber plantations The technology for rubber plantation requires rubber trees to be planted with standard spaces between rows of rubber. Weeds that grow between the rows compete for soil nutrients with young rubbers and jeopardize the growth of rubber trees. In order to eradicate weeds the traditional method is either to spray with chemical weed killer or by using manual labour. Chemical weed killers do drastic damage to the ecology. They kill not only weeds but are also harmful to human and other natural living animals. The residual chemicals contaminate the soil and water in the plantations. Rubber planted with a bioplastics bag. Rubber nursery using root trainers. bioplastics MAGAZINE [06/14] Vol. 9 13
