WO1996017807A1 - Method for producing filling compound from warm filling material such as waste and recoverable plastics - Google Patents

Abstract

A method in which a plastic mass is produced from hot filling material like stone, metal and ceramic compounds and unsorted plastics, of which one can produce building material and objects. During the proceeding the heat from the filling material melts the plastics at once without any external supply of heat. By this procedure the succeeding steps of concentration of the compound and the mass are simple and cheap, since the fabrication of the mass at the right temperature only requires already existing filling materials, at which the plastics melt fast. The compound can be fed directly from the nozzle to the direct chill ingot casting practice depending on the product. The fabrication of the compound is a closed system why the melting plastics neither burn or cause poisonous gases. By the method one obtains a solid and durable compound which when it has solidified can replace both concrete and wooden products.

Description

METHOD FOR PRODUCING FILLING COMPOUND FROM WARM FILLING MATERIAL SUCH AS WASTE AND RECOVERABLE PLASTICS

The present invention relates to a method and material with which it is possible to utilize industrially different unclassified waste and recycling plastics. The mass is fabricated and formed either by moulds or directly through nozzles or can be rolled to products like sheets, balks, planks, panels, water flutes, pipes and other construction materials and different kinds of articles like implanting bowls, supports of traffic signs etc.

Miscellaneous plastics waste means here the waste plastics which has been generated in consequence of industrial, commercial and house hold activities and which is normally transported to dump. This far it has not been found any economically profitable

re-use for these materisls. They have been blended for example into asphaltmass.

Incineration

has been investigated in large-scale research projects with poor results.The obstruction of these above named usage's has in most cases been low or negative profitability: the pure transportation and crushing cost has been higher than the cost of heating oil.

As known atone minerals in different forms are able to be used as fillers for plastics.

De-patent 3832743 covens a principle where a blend of 50% quartz-sand (0.063-0.25mm)and 50% (1 ,25-2mm)sand is blended with polymers. The blend is used for floor materials.

British patent 1300221 is based on the manufacturing of synthetical stone. The idea is that one puts different stones of unhomogenous size into mould. The blend is plastisized either by heating up in mould or in oven. With this method can be manufactured

elements and ornaments which are easy to connect in constructions. Netherland patent 8200730 is using sand and for example so called styrox-waste.

These materials are used for manufacturing of construction bars and elements.

Waste plastics (polypropylene-polystyrene and other polymers) of weigh content

1 % to 5% of end product are used in the blend. As a mineral substance is named

sea sand which is heated up to 150 c temperature. The hot sand and the polystyrene foam are blended. The blended mass is mouldable. After cooling the moulded product is a light construction material.

Finnish patent 91249 covers a principle in which hot stone materials are blended with plastic particles. Plastic waste and stones are washed beforehand. The minerals and the plastics are hearted up in contact with water. The manufactured mass is further heated( with water involved) and possibly some filler-material (sand) is added. (

recommended particlesize of sand is 3-4mm).

Further in the method the sand material of size, under 3mm (the best size for the method) is heated up to temperature of 160-220 c. Thermoplastics are added in 10-40% of the dryweight of sand material and the materials are blended. Stone materials of size under 3 mm are scattered in more until the mass is ready made. The mass will be pressed and rolled to products.

The weakness of all known methods is that economically and technically they are not advantageous enough to be used for manufacturing of commercial and economically profitable products from miscellaneous waste plastics.

The weakness of the Finnish patent is the complexity. The washing of raw material is expensive and moisture and use of stones of too limited particle size will debilitate the material. in tests it has been noticed that with the method of patent 91249 ( particle size of sand material mostly below 3mm) it is not possible to get plastics melted.

Another point is that the manufacturing of the mass might demand external heating.

Filling and scattering stages of moulds will make the process more complicated and might easily cause degradation of plastics and lead to decreased binding power. The temperature of filiers is incorrect as well (will be clarified later in the text ). Likewise the washing of stones and plastic particles has to be considered as an expensive and unnecessary operation.

The manufacturing and the structure of hot filler material deviates from the previous methods and materials. There is not used oven or heating in containers or in moulds in the hot filler method. Plastics are totally unclassified and may contain whatever existing plastic grades. The method is universal what it becomes to plastic grades.

in De-patent there is used quartz sand. in Nl- patent sea sand. GB-patent is using different stone material. The material which this application uses can contain whatever stone but not any sand. The sand is only a disadvantage in the process and it will be taken off already in the heating stage of stones or other material. Water is also really harmfull substance and it is used mostly for preventing overheating and as disintegrating substance in plastics industry.

Characterical for this invention are the facts presented in the characteristic part in chapter 1 of the requirement As filter can be used whatever substance only which specific heat is higher than plastic has. in principle the specific heat of material is directly proportional to material's effectiveness. For example steel and ceramic waste and glass are useable. Stone materials are however most easy and cheap filler and heating materials.

The HOT FILLER MATERIAL METHOD is best suitable for particlesize over 5mm.

The highest suitable particle size is not needed to be defined due to the fact that in case the particle size is larger the performance of the method is better. Particle size has to be big enough so that much enough heat energy can be transferred in particles When sand-type under 5mm particle size is used It will form disadvantage substance which will weaken the material. Whether particle size is under 3mm the adhesion will weaken and when using powder type substances like gypsum the miscellaneous waste plastics won't bind ( or stick) the material much enough. in deviation to the Netheriand patent the temperature limits are 300-500 C when in above mentioned patent limits are 125-250C. The heat durability

of the materials is the determining factor when defining the upper limit. ln the

Finnish patent the requirement 10 presents 160-220 C for the temperature

of stones which is not exclusively enough to get average recycling plastics

melted (plastisized).

During tests and test production has became clear that when using temperatures given in the above mentioned Finnish patent the mass shall be heated separately which causes severe troubles in moulding of the product and in handling of the equipment due to sticking and poor heat transfer properties. in the hot filler material method miscellaneous recycling and waste plastics ere

crushed and the particle size of the plastics crash is normally between 1-3 cm.

The thickness depends on used plastics. The size of plastics particles is not

decisive from the process point of view. It may vary in accordance to available

raw material. The thickness of community waste plastics is quite small.

For example the thinness of both film and pot waste is an advantage for this method.

Filler materials e.g. stones are heated up so that the heat amount is capable to

plastisize the plastics directly. The resulted mass is plastics! and dough-tike.

When using gravel or rough stones and the share of plastic is 5-30 weight percent the stone temperatures are deviating between 300-500 C depending on the specific heat of waste materials and the amouth of plastic. In any case the mentioned temperature range is suitable for all beneficial blend types. The specific gravity and the other mechanical properties of stones have an influence to other needed properties of the mass.

The specific gravity of the end product is naturally adjusted with the proportion of filler and plastic.

The plastisizing process is based on equation in which the end heat energy of the mass = the heat energy of fillers- the heat energy needed for plastisizing the plastics.

Due to the mentioned principle there won't be needed any additional heating during or after blending. The mass will be completed directly with the heat energy content of the fillers and within given temperature limits,

During manufacturing process the heated fillers are fed by screw or by some other device into mixing unit. At the same time plastic crush is fed into the same unit too. The melting starts immediately when the hot filler material and plastic crush contact.

Fillers which are hot enough (between 300-500 C) stick with the plastic crush.

The plastic will encircle the filler material immediately. With light mixing is obtained homogenous mass into which plastic can be added during mixing. Two different methods are able to be used in feeding. Either one mixing stage ( the right blend is directly obtained) or adding method ( fine crushed plastic is fed to mixing unit). Hot stones in the above mentioned temperatures are not needed to be added. Plastics are needed to be added only in case the melting temperature of base raw material is too high. For example the waste plastics

of industry which are able to be plastisized in around 200 C are needed to be added plastics able to be plastisized in lower temperatures, It's possible to make the adding either before mixing or directly to the mixing unit. Due to the fact that the distribution of waste and recycling plastics is varying It has to be defined every time separately whether the process is functioning or not.

Assured result will be reached when over 50% of plastics are able to be plastisized in temperature below 180 C. Due to this one has to add plastic occasionally into

the blend.

Hot filler materials and malting plastic is kept under unoxygen or nitrogen circumstances so that plastics won't bum and become spoiled as well for example PVC can't bum and format toxic fumes or gas. Normally It is sufficient that the mixing unit is fulfilled with plastic and filler and therefore the oxygen content is low. The plastic which is still unmelted will prevent air to leak into mixer and on the other hand the ready made mass won't absorb oxygen. The construction of the mixer is almost enclosed therefore no burning will occur.

The construction of the mixer is either screw or level type. These areas of the

process won't include any matters which weren't currently Known.

The heating of fillers is normally made for example in stone drums used by asphalt industry From tecnnical point of view it's important that the heat energy of fillers is optimized in relation to plastics used. Whether the energy control accurancy of the stone drum is not enough there can be used intermediate container in which the heat energy is corrected by residence time. These matters can be determined only by making test runs by each blend^, No calculatory basics for miscellaneous mass for determining the needed energy can be defined.

The advantage of the hot filler material method is that industrial process is easily reached and different kinds of plastics and filler materials can be flexiblely used . It's easy to build different moulding and laminateing lines following the equipment producing plastical mass.

The big advantage of the hot filler material method is that the blends are easy to control and the manufacturing is easy to automatizate.

Blending of stones and plastic is difficult in non-plastic state because of big differences in specific weight. Transferring of the mass from ovens or from heated containers into moulds or to laminateing is rather expensive. In the hot filler method the ready made mass is possible to transfer directly for example to slipforming operation casting, air has been pressed out of the mass already in the stage of

An important advantage of the method is that the plastisizing degree of the mass is possible to be determined according to the temperature of fillers and by possibly preheating.

Thin film- type flakes will melt in some seconds when in contact with stones. Melting will slow down after the plastic is encircleing the filler. It is possible to keep the mass in plastical form without specific insulation ca. 15 minutes. Forming of the end product has to be made within that time.

In some cases the plastisizing degree of the mass is triad to be kept rattier low so that the temperature of the plastic won't rise too much. For example in case of normal community waste plastic it is worth to aim to reach plastisizing degree of 70% due to the fact that they contain over 70% polyethylene plastics which can be plastisized in ca. 150C temperature. In case of waste plastics whether the goal would be perfect plastization it would be harmful for plastics included which plastization temperature is low (they would over heat). An example is stone plastic balk ( 5×5 cm) made with this method. The raw material is community recycling plastic which contains 70% plastics which are possible to be plastisized under 180C. Normal round shape miscellaneous gravel with specific weight 2.5 kg/m is heated to 400C. Stone material and plastic crush (60 C ) is evenly fed into mixer unit which is of screw-,peg- or blade type.

Plastics and stones ire blended 30 seconds in cone type mixer and the mass is pressed with hydraulic device or with screw through nozzle into sliding mould which is rolled by the same,

After that the product is ready and it can be cutted to pieces and cooled down.

The same way moulds can be filled through nozzle by taking the mass directly from pressurized mixer unit or it is possible to fill moulds which will be pressed afterwards. The used practice depends on product.

Claims

PATENT DEMANDS

1)

The present method relates to manufacturing of hot filler material mass from unwashed unclassified and miscellaneous recycling- and waste plastics and It is known

that fillers like stones, metals, ceramic and those blends which specific gravity is over 1 and they are more rough than sand and preheated or not preheated unwashed miscellaneous dry plastics are blended directly in a right share mass of fillers and plastics in mixing unit. The fillers are preheated with specific heating unit in temperature of 300-500

C.

After that the fillers end the plastics are mixed in mixer unit which manufactures ready made plastical mass without needing any external heating in mixing phase in addition to the heat energy

which the fillers have.

2)

The method named in patent demand 1 known that from miscellaneous waate plastics will be made a blend in which the share of plastics which are able to be plastisized under 180 C is at least 50%.

3)

The method named in patent demand 2 known that plastic particles and fillers are not washed before

mixing.

4)

The method named in patent demand 1 known that the particle size of fillers is over 5mm

5)

The method named in patent demand 1 known thet the plastisizing degree of blend in question

is adjusted by the heat energy content of fillers and preheating of plastics.