Intensive technological development and a dynamic growth of production using various chemical raw materials have a direct impact on the generation of huge amounts of waste. At the same time, the consumption and price of basic raw materials increase.
The basic raw materials for many industries, including the plastics industry, are, i.a., substances of petrochemical origin. They are produced from natural gas, crude oil and other hydrocarbon mixtures. Due to the increasing limitation of resources and access to these raw materials, their prices fluctuate significantly, and buyers have to take into consideration increasingly higher production costs.
Currently, the global industry focuses more and more on the design and implementation of waste-free technologies or technologies that significantly reduce the amount of production waste. The use of by-products is also increasing.
The industrial use of recyclable materials is dictated not only by the availability and price of standard petrochemical equivalents, but also by ecological, technical and social factors. The quality and origin of products, the possibility of expanding the product portfolio and the clearly visible ecological trend justify the choice of sustainable recycled materials for the production of new polyesters for polyurethanes and new, green generation unsaturated polyester resins.
PCC Group – a producer of raw materials, additives and chemical formulations for industry – is one of the producers of chemical raw materials recognising the potential in recycling and non-waste technologies.
An example is the use of recycled PET materials for the production of selected types of polyols.
In addition, the companies of the PCC Group develop and implement a technology for the production of adhesives for rebond foams obtained from mattresses, as well as adhesives for SBR and EPDM granules made of ground-up used car tires.
PET is a synthetic material from the group of polymers that has been known since 1941. Its full name is ‘polyethylene terephthalate’, i.e., polyester terephthalic acid ethylene glycol. Polyethylene terephthalate has a linear structure. It is obtained in the process of polycondensation. Recycled PET materials are used in a variety of industries, including the chemical industry.
The extraordinary popularity of PET (polyethylene terephthalate) in industrial production results primarily from its very useful physical properties that determine the versatile use of this material. PET is a plastic material with a high level of stiffness and hardness. It is also characterised by high chemical resistance.
PET has also high mechanical and heat resistance. It shows very high impact strength and stability in a wide temperature range. It is easy to process and maintains high shape stability. In addition, it has low water capacity, and is resistant to corrosion and weather conditions. PET plastic also has good dielectric properties.
The PET material is also resistant to fats, alcohols, fuels and lubricants. It does not contain low molecular weight compounds and is physiologically neutral. Thus, it has been approved for contact with food. Therefore, it ensures safe storage of food products.
In addition to the standard PET, there are also special types of this material. These include, e.g., PET TX (enriched with a lubricant) or PET GF-30 (enriched with glass fibre). Various types of PET material determine its wide application in many industries.
However, it also has its disadvantages. One of them is the loss of mechanical properties at high temperatures. Besides, it is not a biodegradable material, which contributes to environmental pollution. One should also note that PET recycling requires remelting.
The positive properties of PET and the low cost of obtaining material for it contribute to its wide application. PET is primarily used in the production of packaging in the food industry (plastic bottles for beverages, jars, etc.). The material is also used in the engineering and automotive industries for the production of parts of the fuel system, air conditioning elements, and so forth.
In the electrotechnical, electromechanical, electronics and household goods industries, PET is used for the production of precision bearings, levers, cams, gear wheels, housings with specific mechanical and electrical functions, e.g., in office machines, computers, monitors, printers, kitchen appliances, lamp covers, photo accessories, as well as sockets, plugs and capacitor bodies.
PET is also used in the production of sports equipment. This material is used in the manufacturing of, e.g., ski bindings and sailing accessories. Recycled PET is also suitable for the production of fleece outerwear.
The strength of PET is not only an advantage, but also a disadvantage. Plastic waste can stay in the environment for ages. It is not only a question of biodegradation, but also of the slow release of various harmful substances into the environment. These compounds, often very toxic, get into the soil, air and water, disturbing the natural ecosystems. Therefore, it is imperative to ensure that as much PET waste as possible is recycled for re-use in various industries.
Aromatic PET-containing polyester polyols
For the production of polyester polyols of the Rokester series, the PCC Group uses, i.a., waste PET from used plastic beverage bottles and other packaging.
The PET granulate obtained in the recycling process is heated. It is then converted into a liquid polyester polyol with the aid of suitable catalysts and auxiliaries.
Polyols produced on the basis of recycled PET are high-quality, full-value products that can be used equally with products made in a conventional way. Due to the content of aromatic groups, they reduce the flammability of the final product.
Polyols produced on the basis of recycled PET are dedicated mainly to the construction industry. They are used for the production of new polyurethane materials with very good performance properties, in particular for the production of spray foams, sandwich panels, rigid block foams, insulation boards, single-component OCF assembly foams, elastomers and adhesives.
The PCC Group is also a producer of specialised polyurethane adhesives dedicated to the production of rebond foam. Its production uses polyurethane foam from discarded mattresses.
The 5–10 mm pieces of foam recovered from the mattresses are then cleaned and sprayed with a suitable polyurethane adhesive. They are placed in a special mould, in which they are compressed at high temperature (30–50 °C). This creates a new foam. The curing time of the material depends on the type and amount of adhesive and the type of foam scraps used.
The rebond foam is a soft, durable and at the same time economical material. It can be used in applications from which it was obtained after reprocessing (e.g., production of mattresses). Rebond foam is most often used for the production of upholstered furniture, insulating and sound-absorbing mats, rehabilitation mattresses, gymnastic mats, elastic suspended ceilings in sports halls, sleeping mats in truck cabins, sports guards, inserts for sports, and rehabilitation equipment. It is also perfect as an amortization pad in transport vehicles, e.g., of glass, and as a pad for household carpets.
Single-component polyurethane adhesives for SBR rubber granules from the recycling of vehicle tyres
The product portfolio of the PCC Group also includes specialised polyurethane adhesives, dedicated to bonding black SBR or EPDM granules obtained, i.a., from ground-up car tires.
Standard adhesives are colourless or light-coloured. The manufacturer’s portfolio also includes adhesives containing a red or green dye, which, during spray application, change the colour of the black granules into the colour of the glue. In this way a surface in the colour of the glue is created. At the customer’s request, it is possible to develop other glue colours.
SBR or EPDM granules are used for the production of speed bumps and sports surfaces such as soft running tracks, anti-slip mats for playgrounds, and others. The glue must be properly matched with the granules. Using the wrong glue will prevent the granules from sticking together effectively. The curing time of the adhesive depends on the temperature, thickness of the glued granulate and the catalyst added at the time of application. It can be reduced by adding water, catalyst or a solution of each to the adhesive.
