PROPA S.A.is part of Empresas CMPC, the largest integrated forestry group in Latin America, and one of the top one hundred in the world. With a tradition of experience going back more than 80 years and with an integrated focus on the forestry business, the operations of CMPC embrace everything from the handling and exploitation of forest properties, the production of wood, cellulose and different types of paper to the manufacturing of containers, packaging, mass consumer items such as hygiene products, to notebooks and others paper-based products.

PROPA is the business area of Empresas CMPC, which specializes in the manufacturing, and commercialisation of multiwall paper sacks. Because PROPA is an integrated converter it is able to count on a source of kraft paper of excellent quality to manufacture its sacks, and because of the technical and commercial knowledge within the organization, (the result of decades of experience in the business), PROPA has reached an enviable position of leadership in the Latin American market. PROPA’s history began almost simultaneously with the birth of CMPC. Already in the 1930s, paper sacks were being produced in the paper products plants located in Ñuñoa and later in Puente Alto. In 1972, PROPA inaugurated the Chillán paper sack plant, in response to the growing use of multiwall sacks, mainly in the cement market. This plant was enlarged at the end of the ‘70s, and successive improvements have allowed PROPA to become the main supplier of paper sacks to the Chilean market and to open a new era as an exporter to Latin America. With its diversity of products, PROPA is present in a wide variety of markets, such as construction, agriculture, chemical products, human foodstuffs and other industries, not only in Chile but also in most Latin American countries.

CMPC Sackraft Paper. Properties. Apart from using only virgin fibers of radiata pine, as the case of the papers produced by CMPC, to obtain a specialized paper with a high resistance it is very important their manufacturing process. By means of the Clupak process, it is possible to obtain papers called extensible, with a bigger elasticity, which allows the sacks to be able to absorb a larger quantity of energy without splitting. The Clupak process consists in the generation of microdeformations in the paper, invisible at first sight, which allow the paper to suffer a bigger elongation in the case of external requirements. Additionally, in the last years developments have been produced in new technological processes in paper manufacturing. The most important among them, already incorporated by CMPC, it is the high consistency refining process. With this, important improvements have been achieved in different attributes of the products and specially in their resistance properties. This has allowed the manufacturing of papers with smaller quantities of grammes without diminishing that characteristic in the containers.

Raws Materials: The manufacturing of papers with properties of high resistance begins with an appropriate selection of the type of cellulose to use in their elaboration. A direct relationship exists between the length of the constituent cellulose fibers of the paper and its resistance grade, this is: the bigger the length of the fibers, the greater the capacity of the paper to absorb energy without splitting. The cellulose extracted from the radiata pine, used in the plants of CMPC, possesses a length of fiber which is one of the longest used nowadays in the world in the manufacturing of papers for sacks. So, the use of this kind of cellulose in paper elaboration gives the containers excellent resistance qualities.

Types of Sacks

The type of multiwall sack to be used for a certain application depends on a number of factors, including, the physical characteristics of the type of product to be packed, the way in which it will be transported, stored and distributed, and the way in which it will be used by the final customer, amongst other things. The types of sacks that PROPA manufacture at the moment are the following:

Open mouth, Pasted bottom Sack.

Advantages: It doesn't require a special packing machine to be filled. It allows the insertion of an interior plastic liner. Disadvantages: Quality of palletizing is only fair because the sack is not symmetrical. Requires some sort of closure once the sack is filled. Main uses: Powdered milk, Starch, Wheat Flour, Minerals, Plastic Resins. Also as a container of smaller units (noodles, flour, rice)

Open Mouth Sewn Bottom Sack.

Advantages: It doesn't require a special packing machine to be filled. It allows the insertion of an interior plastic liner. Disadvantages: Forms unstable pallets because the filled sack resembles a "pillow". Requires some sort of closure once the sack is filled. Main uses: Corn Seeds, Fertilizers, Wheat Flour, Oats.

Valved, Pasted Bottom Sack

Advantages: Palletizing is very stable because the filled sack resembles a block. The valve closes due to the internal pressure of the product, and for that reason, it doesn't require closing after filling. Designed for high-speed automatic or semi-automatic packing machines. Disadvantages: Requires a special packing machine to be filled. Not possible to insert a plastic liner. Main uses: Cement, Mortars, Chemical Products, Sulphur, Plaster.

Sewn Valved Sack.

Advantages: The valve closes due to the internal pressure of the product, and for that reason, it doesn't require a closing after filling. The sack can be opened easily at the sewn end. Disadvantages: Requires a special packing machine to be filled. Not possible to insert a plastic liner. Quality of palletizing is only fair because the sack is not symmetrical. Main uses: Wheat Flour, Bentonite.