Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J11/00—Recovery or working-up of waste materials
  • C08J11/04—Recovery or working-up of waste materials of polymers
  • C08J11/06—Recovery or working-up of waste materials of polymers without chemical reactions
  • C08J11/08—Recovery or working-up of waste materials of polymers without chemical reactions using selective solvents for polymer components
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D125/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Coating compositions based on derivatives of such polymers
  • C09D125/02—Homopolymers or copolymers of hydrocarbons
  • C09D125/04—Homopolymers or copolymers of styrene
  • C09D125/06—Polystyrene
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J125/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Adhesives based on derivatives of such polymers
  • C09J125/02—Homopolymers or copolymers of hydrocarbons
  • C09J125/04—Homopolymers or copolymers of styrene
  • C09J125/06—Polystyrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2325/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Derivatives of such polymers
  • C08J2325/02—Homopolymers or copolymers of hydrocarbons
  • C08J2325/04—Homopolymers or copolymers of styrene
  • C08J2325/06—Polystyrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/05—Alcohols; Metal alcoholates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/10—Esters; Ether-esters
  • C08K5/12—Esters; Ether-esters of cyclic polycarboxylic acids
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

• the present invention relates to a method for dissolving expanded polystyrene (EPS), allowing the recycling of waste based on this material.
• EPS expanded polystyrene
• This process calls for the use of two types of solvents: a so-called initial solvent, making it possible to destructure the polymer and a so-called complementary solvent, making it possible to obtain said polymer in the form of a true solution.
• the invention also relates to a true EPS-based solution, capable of being obtained by said method, and which can be used in various applications such as the formulation of adhesive, mastic, varnish sealant, resins, paint or lacquer.
• the magma is obtained by treating EPS with the aid of a treatment solution comprising a major proportion of a solvent such as acetone, a minor proportion of a non-fatty lubricant, such as glycerol, which gives a non-sticky surface finish, and, if necessary, alcohol in sufficient quantity to bind the solvent and the lubricant.
• the magma thus formed has a reduced volume compared to the treated EPS and a non-sticky consistency making it easy to transport and handle.
• the process for obtaining magma described in international application WO 99/07776 is simple and effective.
• the magma obtained according to this process can be used in conventional injection, extrusion or molding processes in the plastics industry, as a semi-finished material pasty.
• this magma tends to dissociate into two phases: the first, on the surface, is a mixture, generally transparent, of liquids, called supernatant; and the second, below the surface, is a mass of condensed, opaque and undissolved material whose microscopic appearance is similar to a gel of high viscosity and whose physical properties are characteristic of a heterogeneous system.
• the term “gel” is understood here to mean a molecular structure in which the molecules form a three-dimensional network by strong electrostatic interactions (ionic or Van der Walls bond) or by crosslinking, and which results from the coagulation of a colloidal solution. .
• These different phases are, in general, hardly miscible, even if mechanical mixing work is carried out.
• the gel which contains polystyrene and represents the recoverable part of the magma, assumes an inhomogeneous appearance due to the state of constant equilibrium which exists between the solvent and the gelled polystyrene.
• This inhomogeneity can make its industrial transformation difficult into products such as adhesives, paints, varnishes or lacquers.
• to prepare these products it is important to be able to fractionate the magma as many times as necessary without observing any variation in its composition or in that of the products formed.
• the inventors have sought to solve this problem in order to provide a product for recycling EPS, which remains homogeneous over time and which can be used to prepare products such as adhesives, paints, varnishes or lacquers.
• this relates to a process for dissolving the EPS, characterized in that: i) the EPS is brought into contact with at least one initial solvent making it possible to pass the EPS from a solid state expanded to that of a gel; and ii) contacting said gel with at least one additional solvent, distinct from the initial solvent, allowing the solubilization of said gel so as to obtain a true solution.
• the initial solvent and the additional solvent can, depending on the invention intervene in the process in the order indicated or simultaneously.
• true solution is meant a homogeneous dispersion of molecules in a solvent.
• the true solution is not colloidal, unlike gel, which is a type of colloid in which a liquid contains a solid forming a fine network, extending continuously. Depending on the balance that is established between the solvent and the solid, one of the phases of the other may come in excess. In the case of a true solution, on the contrary, the solid phase disappears and is found diluted when an excess of solvent is added.
• the solubility of polystyrene in a solvent is explained by the neutralization of the association forces between the macromolecular chains which ensure the cohesion of the polymer.
• a solvent can thus be characterized by its solubility parameter, which is a measure of its internal energy density of cohesion allowing it to maintain in cohesion molecules in the liquid phase.
• the solubility parameters of the solvents are determined from the heat of vaporization and the molar volumes of the said solvents by the formula of HILDEBRAND, according to the following equation: or :
• HV is the latent heat of vaporization (cal)
• T is the temperature in ° K
• V is the molecular volume (in cm 3 ) Its unit of measurement is usually expressed in (cal / cm 3 ) 1/2 .
• Each solvent is characterized by a specific value of ⁇ , which may vary slightly depending on the experimental data from which it is calculated. The values mentioned below are taken from the following work: Engineering techniques, treated plastics and composites (1997), polymers in solution, Perrin, P. and Hourdet, D.
• An initial solvent and a complementary solvent according to l The invention have different solubility parameters.
• An initial solvent according to the invention is a solvent whose parameter solubility is greater than the PES solubility parameter. Generally the initial solvent has a solubility parameter greater than 9.5 (cal / cm 3 ) 1/2 .
• the solubility parameter of the initial solvent is in the range 9.6 to 11.0.
• a solvent is also called a latent solvent or diluent; it alone does not allow the PSE to be completely dissolved.
• the solvents used are preferably organic solvents resulting from the refining / recycling of petroleum products or products of plant origin, or else produced by biotechnological processes.
• the solvents reported in Table 1 below can be used as the initial solvent within the meaning of the invention. Table 1
• the preferred initial solvents are butyronitrile, isophorone, n-butyl lactate, methylisobutylcarbinol, chloroethylene, ethyl-2-hexanol, methylene chloride, cyclohexanone and, more particularly, acetone.
• An initial solvent of the invention is preferably miscible with water. The inventors have observed that the effectiveness of the process according to the invention is conditioned by the amount of residual water present on the surface of the EPS or absorbed by the EPS. It is estimated that the EPS has the capacity to absorb from 5 to 50 g of water per m 2 of contact surface.
• the method for dissolving the EPS described above comprises a prior step according to which the EPS is washed with an initial solvent solution containing water, for example, an acetone solution. , ethanol or propanol or any other initial solvent of the invention.
• an initial solvent solution containing water for example, an acetone solution. , ethanol or propanol or any other initial solvent of the invention.
• An initial solvent of the invention is therefore preferably a water-miscible solvent making it possible to prepare an aqueous solution of said solvent for washing the EPS, such as acetone.
• the preliminary washing solution of the EPS is preferably an acetone solution containing from 5 to 40% water, more preferably 10 to 30%.
• Such a true solution has many advantages, among which one can cite a lower flammability, a low toxicity and a physicochemical stability of at least two years in suitable barrels.
• step i) of the solubilization process consisting in bringing the EPS into contact with at least one initial solvent, is carried out in the presence of an anhydrous salt making it possible to trap the absorbed residual water by the PES or present on the surface of the PSE.
• the anhydrous salt is of the calcium sulphate type.
• the anhydrous salt can be immersed directly in the solvent in order to dehydrate it, especially when a solution of solvent and water has been previously used for washing the EPS, or it can be contained in cartridges through which have circulates the solvent used.
• This second possibility allows the recycling of the solvent, but also that of the anhydrous salt contained in the cartridge, because the cartridge can be changed and the salt that it contains dehydrated.
• 1 to 10% of anhydrous salt is added to the solvent, preferably 5 to 10%.
• the amount of water collected is of the order of 0.1 to 0.4 g of water per gram of anhydrous salt.
• a complementary solvent suitable for the present invention preferably lies in the range of ⁇ varying from 8.5 (cal / cm 3 ) 1 2 to 9.5 (cal / cm 3 ) 1 2 , more preferably between 8.7 (ca ! / cm 3 ) 1/2 and 9.3 (cal / cm 3 ) 1/2 .
• the additional solvent is preferably chosen from ketones comprising at least 3 carbon atoms, such as methyl ethyl ketone (EK), halogenated aliphatic compounds, such as trichloroethane, organic esters, such as ethyl acetate, or aromatic alcohols, such as phenylcarbinol.
• EK methyl ethyl ketone
• halogenated aliphatic compounds such as trichloroethane
• organic esters such as ethyl acetate
• aromatic alcohols such as phenylcarbinol.
• the additional solvents make it possible to obtain good homogeneity and satisfactory physical stability of the true solution according to the invention.
• the physicochemical characteristics of the solvents used in the context of the process of the invention are chosen so as to comply with regulatory or legislative, health and safety requirements. Thus, they do not present any toxicity or harmfulness incompatible with the technical applications envisaged.
• the most suitable additional solvents are: cyclohexamine, ethyl acetate, butyric acid, chloroform, mesityl oxide, methyl ethyl ketone, 1-chlorobutane, amyl acetate, l n-butyl acetate, methylal, methylisoamyl ketone, methyl isobutyl ketone, propyl acetate, diethyl ketone, ethylbenzene and xylene.
• ethyl acetate is preferred.
• the initial solvent generally represents between 10% and 70%, of preferably between 30% and 70% of the volume of the final true solution, and the amount of additional solvent represents between 10% and 70%, preferably between 10% and 50% of the volume of said final true solution.
• the proportion of additional solvent represents between 1% and 30%, preferably between 15% and 30% of the volume of the initial solvent; more generally, the volume ratio between initial solvent (s) and complementary solvent (s) is greater than 1.
• the amount of EPS used for the invention is usually between approximately 0.2 and 1 kg per liter of initial solvent, and preferably between 0.5 and 1 kg.
• the process of the invention involves acetone as the initial solvent and ethyl acetate as the additional solvent.
• the present invention also relates to a composition allowing the solubilization of the EPS, capable of being implemented for the purposes of the process of the invention.
• This composition comprises: an initial solvent enabling the EPS to pass from an expanded solid state to that of a gel; at least one complementary solvent distinct from the initial solvent, allowing the complete solubilization of said gel so as to obtain a true solution.
• the nature, quantities and proportions of each of the components present in this composition are as defined above for the purposes of carrying out the method according to the invention.
• the invention also consists of a true solution capable of being obtained by the method of the invention.
• This true solution is characterized in that it contains: polystyrene; an initial solvent enabling the EPS to pass from an expanded solid state to that of a gel; at least one complementary solvent distinct from the initial solvent, allowing the complete solubilization of said gel so as to obtain a true solution.
• 1 kg of true solution preferably comprises between 0.2 and 0.8 kg of PSE, more preferably, between 0.3 and 0.6 kg of PSE.
• the true solution may comprise additives, in particular a plasticizer such as those mentioned below, preferably in a proportion of between 5% and 20% by volume relative to the total volume and more preferably between 10% and 15% by volume per compared to the total volume.
• the true solution may also contain a tackifying agent, such as rosin, in a proportion which preferably varies between 10% and 20% by volume relative to the total volume.
• a true solution according to the invention can be used to prepare different products, which constitute another object of the invention. These products may consist of paint, sealant, sealant, varnish, resin, paint or lacquer or an adhesive. To prepare such products, the true solution of the invention is used, to which one or more additives such as a dye, a pigment, a tackifying agent such as rosin, a cohesive agent, such as a alcohol such as ethanol, a filler to increase the volume or a plasticizer, which may be required to impart the desired flexibility.
• additives such as a dye, a pigment, a tackifying agent such as rosin, a cohesive agent, such as a alcohol such as ethanol, a filler to increase the volume or a plasticizer, which may be required to impart the desired flexibility.
• the preferred plasticizers belong to the following product classes: dialkylphthalates, diarylphthalates, dialkylarylphthalates, triaryl- phosphates, triarylalkylphosphat.es and trialkylphosphates. Examples of products of these classes which may be suitable are mentioned in Table 3 below: Table 3
• Dioctyl phthalate is a preferred plasticizer.
• the present invention also relates to the use of the true solution according to the invention for the preparation of a solid, pasty or liquid composite article.
• These articles prepared from the true solution can consist of pasty or liquid products such as adhesives, in particular for wood and paper, varnishes, coatings, seals, paints and lacquers as well as solid products consisting in particular of agglomerated particle boards.
• the liquid or pasty article may consist of a peelable product for the temporary protection of windows, hydrophobic varnishes for roofing tiles, temporary flexible joints for buildings, new adhesives.
• An adhesive according to the invention may comprise a mixture of several true solutions obtained according to the method of the invention, or a true solution with an appropriate additional organic solvent.
• An adhesive according to the invention can also contain anti-UV agents.
• the true solution can also be used to regenerate or synthesize a polymer or copolymer based on styrene in an expanded or unexpanded form.
• the examples presented below illustrate the invention.
• EXAMPLE 1 Preparation of the EPS for its chemical treatment
• Used cases of EPS which have been used for the refrigerated transport of foodstuffs (ex: fish) were recovered with a view to their transformation by the solubilization process of the invention.
• the boxes have been stripped of heterogeneous elements that may surround them such as paper, fasteners or plastic packaging, then passed with a water jet so as to remove organic impurities and other encrustations.
• the residual water on the surface of the EPS or absorbed by the EPS locally makes the action of the initial solvent ineffective during the chemical transformation of the EPS. It was undertaken, as shown in Table 4 below, washing tests and rinsing of the boxes prepared above with an acetone solution in which the percentage of water was varied.
• the densification time is around 18 seconds.
• the densification time increases to 64 seconds. If rinsed, this same EPS washed with hard water with an acetone solution containing 5% water, the densification time is reduced to 29 seconds. It therefore appears that a preliminary washing step with an acetone solution containing water makes it possible to treat wet or soiled recovery EPS, without significantly hampering the solubilization procedure which will follow.
• the gel is in the form of a two-phase body characterized by the existence of a first phase consisting of a transparent mixture of liquids, called supernatant, and a second phase consisting of an opaque condensed material , without real cohesion.
• a true solution was prepared in accordance with the invention using the gel formed in point 1 / above, to which was added either methyl ethyl ketone (MEK) or acetate d ethyl in proportions such that a homogeneous solution is obtained.
• MEK methyl ethyl ketone
• the true solutions obtained are used in the examples below.
• the open time designates the maximum duration after coating during which the gluing is effective.
• the ease of coating is dependent on the fluidity and the homogeneity of the adhesive.
• the open limit time corresponds to the disappearance by evaporation of a percentage of solvent such that the film loses its tackifying properties (tackiness), which means that it no longer develops any interaction with the substrate. that it should stick.
• tackiness tackifying properties
• EXAMPLE 3 Mechanical properties of the yray solution
• the same test was carried out using a vinyl adhesive marketed under the brand RAKOLL ® 6XL-3 / F-Neu. The results of these two tensile tests at 1 mm / min " 1 on a test piece in pine are shown in Table 9.
• EXAMPLE 4 Addition of plasticizing agents and tackifying resins to the yray solution
• the dioctylphthalate (DOP) was tested as an additive for a true solution obtained from a gel according to Example 2 to which added 12% ethyl acetate.
• DOP is in the form of a liquid, the boiling point of which is 365 ° C and the solidification point of which is -50 ° C.
• the percentage of DOP in the true solution was varied.
• the procedure for testing the mechanical properties of the adhesive obtained is the same as that set out in Example 3.
• the mechanical parameters obtained for the different formulations comprising a variable% of DOP, are given in Table 10, below. .
• EXAMPLE 6 formulations of products made from yray solution.
• the true solution used to prepare the products described below comprises 85% by volume of gel as defined in Example 2 and 15% by volume of MEK.
• Hexolit® AP 422 (Clariant); 21% charge (ex: talc or chalk);
• halogen-free flame retardant particle board A particle board is obtained by mixing: 13% of true solution; 36% wood particles;

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Paints Or Removers (AREA)
• Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)

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• 2003
  • 2003-12-31 FR FR0315621A patent/FR2864544B1/fr not_active Expired - Fee Related
• 2004
  • 2004-12-30 JP JP2006546267A patent/JP2007518851A/ja active Pending
  • 2004-12-30 WO PCT/FR2004/003416 patent/WO2005073303A1/fr active Application Filing
  • 2004-12-30 CN CNA2004800422347A patent/CN1922250A/zh active Pending
  • 2004-12-30 EP EP04817619A patent/EP1713855A1/de not_active Withdrawn
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