the present invention provides a new plastic film , for example based on ethylene copolymer ( generally polyolefins ) in which there has been introduced lignin which behaves as an organic biodegradable additive and which is consumed by the microorganisms , without reducing the other characteristics of the product , in particular its mechanical properties . lignin which is in the form of a powder can result from the processes presently known and used for the manufacture of paper pulps , such as a process as follows known under the following definitions : or any other process for obtaining lignin of a good purity , i . e . not a lignin contaminated by chemical products such as sulphonates , soda , bisulphite . . ., and being in the form of pulverulent powder ( with a grain diameter of about 1 to 5 microns ), which permits making homogeneous films of a small thickness of about 20 ± 5 microns . lignin is a polymeric vegetable material made of methoxylated and hydroxylated cores forming a three - dimensional structure . it is a by - product obtained in the manufacture of paper pulp . the vegetable origin of lignin classifies it in the category of renewable products and , since it does not spoil the earth natural resources , lignin can be considered as an ecoproduct . due to the excellent compatibility of lignin with the ethylenic copolymers , the weight contents of lignin in the thermo - plastic polymer of the degradable plastic film , can be as high as 75 % but will be preferably adjusted between 3 and 25 %, which implies the use of master mixtures . the combination of the photodegradable , biodegradable and oxidizing properties of lignin can be advantageously used here for obtaining a degradable film . actually , lignin which is a vegetable material , biodegradable by mushrooms ( micromycetes ) and bacteria , contributes under certain conditions to the embrittlement of the plastic film . if measures are taken to add photoactive and / or oxidizing additives ( such as a pro - oxidizer to the master mixture , a degradable film will be made according to two processes : one being a chemical process , for example : photodegradation or oxidization , or a combination of the photodegradable and oxidation processes the plastic films thus obtained can be used for many agricultural applications , as well as for the manufacture of plastic bags for refuse , bags for various scraps , shopping baskets , etc . in the agricultural applications , in which the solidity of the film is essential when it is laid on the ground for the first time , the lignin containing polyethylene film of the present invention appears particularly interesting to use since the degradation of the film over time is total , both for the surfaces which are outside the ground and for those which are buried inside the ground ; still in the agricultural applications field , the adsorption and absorption capacities of lignin , up to 50 % by weight , of essential oils , insecticides land the like , will permit then a use of lignin as an additive for the new fungicidal , rat - killing or other properties . likewise , the adsorption properties of lignin can be utilized so that the lignin can be incorporated into the photoactive products prior to its mixture with the copolymers , which has the advantage of increasing the homogeneity and therefore the degradability of the film . on the other hand , this lignin containing plastic film can be coextruded , and can therefore be a part of a composite film with several specific layers . it should further be noted that the mechanical properties of the lignin containing degradable film of the present invention are comparable to those of a now film which does not contain any lignin acturally .