MXPA05005258A - Flame retardant outer coating applied to expandable polystyrene (eps). - Google Patents

Abstract

The present invention refers to a coating having a fire-resisting agent applied to expandable polystyrene (EPS). Said composition improves the EPS performance during the transformation process thereof, and includes components harmless to human and animal health. The purpose of the present invention is to provide an expandable polystyrene coating useful for both the construction industry and the food packing industry indistinctively since it does not contain substances such as HBCD which affect human health and the environment. The invention also improves the performance of EPS during the transformation process thereof.

Description

EXTERNAL COATING WITH RETARE) ADOR OF FLAME APPLICABLE TO EXPANDABLE POLYSTYRENE (EPS) FIELD OF THE INVENTION Expandable Polystyrene (EPS) Due to its excellent qualities and properties to which its ease of forming and manufacturing possibilities are linked, this material has a very wide field of application. The current and future construction is characterized by the demands of energy saving, protection against noise and the environment. And the field of food, polystyrene expandable presents a wide range of containers and packaging that facilitate this industry in food. In all its applications, the Expandable Polystyrene require compliance with fundamental characteristics that do not endanger the environment, human and animal health. Expanded Polystyrene-EPS is obtained from the transformation of expandable polystyrene. This raw material, expandable polystyrene, is a styrene polymer that contains an expanding agent: pentane. Expanded or expanded polystyrene does not use, nor has ever used, expanding gases of the family of CFCs, HCFCs, and HFCs and therefore, its manufacture and use does not entail any type of effect on the degradation of the ozone layer. Like all plastic materials, expandable polystyrene ultimately derives from petroleum.

So that Expandable Polystyrene complies with fundamental characteristics that do not affect the environment, and do not endanger human and animal health. The polystyrene industry has taken the following measures: 1.- For the use of this material in construction polystyrene contains a material that makes it fireproof (self-extinguishing) and safe for the construction and packaging of non-food products. 2 - For the polystyrene products that are in contact with food, the use of the Hexabromocyclododecane (HBCD) antiflama is not used. Since according to studies conducted the use of HBCD showed that they put at risk human and animal health.

BACKGROUND Unfortunately the enormous growth use and production of the Expandable Polystyrene (EPS) makes run the risk of the use of polystyrene (EPS) with antiflama (HBCD) in products that are in contact with food, putting at risk the human and animal health. In addition to recent studies found that the antiflama (HBCD) causes damage to aquatic organisms for their toxicity as shown by the studies. Because of the above The use of anti-flame (HBCD) in polystyrene is being closely monitored and studied by Japan, Canada and the USA. by EPA the Risk Assessment followed by the Risk Reduction Strategy - possible outcomes include 1.- Restricted use of HBCD, 2.- Limited issuance. 3.- Occupational exposure limits. Even though the results are unknown since these should be concluded by the end of 2005 beginning of 2006. These will have the Global Implications ... if it is positive or negative. The EPS Industry must work together with other HBCD users and flame retardant producers to ensure a positive outcome of the risk assessment and manage the risks DETAILED DESCRIPTION OF THE INVENTION For the reasons set forth above, we develop a formulation based on organic additives, which are applied to the Expandable Polystyrene (EPS), giving it excellent self-extinguishing properties, a characteristic required in construction. This anti-flame coating together with other additives do not represent risks to human, animal or environmental health. Expandable polystyrene must have additives or chemicals that guarantee a good performance in its processing.

The polystyrene particles will be difficult to process without coating since they can present: • Clots, adhesion and difficulties to transfer it The coatings are unique for each particle size of the (EPS) · Large spherical particles have less surface area • Small beads have more surface area.

The coatings act as modifiers • Expansion Density • Expansion time • Molding cycle time • Flame retardant Coating formulation: Example 1 Coating for 1 kilogram of Expatible Polystyrene; large particles Zinc Stearate 10% W; Tri-Stearate Glycerin 40% W; Glycerin monostearate 45% W; Micronized Silicon Oxide (Hydrophilic silica) 5% W; Total weight in grams (W) = four grams; Flame Retarder three grams; in such a way that the total weight of the coating in grams will be a total of seven grams. Example 2 Coating for 1 kilogram of Expandable Polystyrene; medium particles Zinc Stearate 10% W; Glycerin Tristearate 15% W; Glycerin monostearate 70% W; Micronized Silicon Oxide (Hydrophilic silica) 5% W; Total weight in grams (W) = three and a half grams; Flame Retarder three grams; in such a way that the total weight of the coating in grams will be a total of six and a half grams. Example 3 Coating for 1 kilogram of Expandable Polystyrene; small particles Zinc stearate 5%; Glycerin Tristearate 50% W; Glycerin monostearate 40% W; Micronized Silicon Oxide (Hydrophilic silica) 5% W; Total weight in grams (VV) = five grams; Flame Retarder three and a half grams; in such a way that the total weight of the coating in grams will be a total of eight and a half grams.

Effect of additives Zinc Stearate (Powder). Product used as antigrumo, generally used in plastics to give greater fluidity in the process eminate the adherence in the lines of the processes.

Tristearate (Powder). Product that helps to release more easily the expander gas contained in the polystyrene, since it causes a micro perforation effect on the already softened particles in the expansion and molding process. (Short process cycles) Monostearate (Powder). Product that serves as a vehicle to tristearate, in addition to acting as antigrumo and helps the fusion of molded particles. (Appearance, texture, brightness) Micronized silicon oxide (hydrophilic silica powder). Product that protects the polystyrene particles from the aggressive contact of the temperature, fluidity in the pre-expansion process, dry and shiny particles.

Flame retardant (liquid). Product that leaves a film in the polystyrene particles without affecting its processing properties, since this product acts chemically only when it comes into contact with fire, absorbing oxygen and thus eHminando the flame; Any of the flame retardant formulations listed below may be used: First Formulation: For every 100 units of flame retardant; 18 units of ammonium sulfate; 18,175 units of ammonium phosphate; 5 units of sodium sulfate; 12 catalase units; 0.025 units of ethylenediaminetetraacetic acid (EDTA); 15 units of formalin; 51 units of Water.

Second Formulation: For every 100 units of flame retardant; 15 units of ammonium sulfate; 10 units of ammonium phosphate; 10 units of sodium sulfate; 5 units of melamine; 2 units of formaldehyde; 58 units of Water.

Third Formulation: For every 100 units of flame retardant; 15 units of ammonium sulfate; 10 units of ammonium phosphate; 10 units of sodium sulfate; 10 units of formaldehyde; 58 units of Water.

Preparation of the Coating.

The additives are weighed: Zinc stearate, gbcerine tnesetearate, glycerin monostearate and silicon oxide (hydrophilic silica) and mixed to form a single one. Weigh the flame retardant The quantities will depend on the amount of EPS to be coated and the particle size Application of the additives to the polystyrene particles 1. - The amount of polystyrene to be coated is weighed and placed in a mixer (concrete mixer) 2 - Flame Retardant is added and stirred for a minute or until an appearance of dry polystyrene fluidity is obtained. 3. Add the previously prepared mixture of additives and stir for a minute and a half.

After this coating operation the polystyrene material is ready for the process of transformation in finished articles of expanded polystyrene passes mainly in three stages: Ia Stage: Pre-expansion The raw material is heated in special machines called pre-expanders, with water vapor at temperatures between approx. 80 and 110 ° C. Depending on the temperature and the time of exposure, the apparent density of the material decreases of about 630 kg / m3 at densities ranging between 10 - 30 g. / m3. In the pre-expansion process, the compact pearls of the raw material are turned into cellular plastic beads with small closed cells containing air inside. 2nd Stage: Intermediate rest and stabilization. When the newly expanded particles cool down, an internal vacuum is created that must be compensated by the penetration of air by diffusion. In this way, the beads achieve greater mechanical stability and improve their expansion capacity, which is advantageous for the next stage of transformation. This process takes place during the intermediate rest of the pre-expanded material in ventilated silos. At the same time the pearls are dried. 3rd Stage: final expansion and molding. In this stage the pre-expanded and stabilized pearls are transported to molds where water vapor is again communicated to them and the pearls are welded together. In this way you can obtain large blocks (which are subsequently machined in the desired shapes such as plates, vaults, cylinders, etc ..) or products shaped with their final finish. Which are guaranteed that they do not represent any risk to human animal and environmental health.

Claims (2)

1. CLAIMS Having described my invention in a sufficient and clear manner, I consider as a novelty and therefore reclassify as my exclusive property, what is contained in the following clauses: 1. External coating with flame retardant applicable to expandable polystyrene characterized by containing stearate zinc, glycerin tristearate, glycerin monostearate, silicon oxide (silica hydrophilic) and flame retardant that is applied by a concrete type mixer to polystyrene particles, this coating is also characterized for not containing substances harmful to the environment and Numanian health such as HBCD or some other halogenated compound, in addition to improving the performance of the particles during their transformation process in finished articles of expanded polystyrene.
2. 2. Flame retardant as claimed in the previous clause characterized by containing formaldehyde, sodium sulfate, ammonium phosphate, ammonium sulfate, mel amine, formalin, ethylenediaminetetraacetic acid (EDTA) and water, which can be applied as a coating to any type of plastic or textile.