Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G8/00—Condensation polymers of aldehydes or ketones with phenols only
  • C08G8/04—Condensation polymers of aldehydes or ketones with phenols only of aldehydes

Definitions

• New phenoplast-type resins obtained from phenolic compounds and macromolecular hardeners carrying aldehyde functions
• the field of the present invention is that of the use of a polymer carrying aldehyde functions as a phenol hardener to obtain phenoplast type resins.
• the present invention more particularly relates to the use of a polymer carrying aldehyde functions, and not the use of formaldehyde, for the crosslinking of phenolic compounds.
• the polymer carrying aldehyde functions, described in the present invention is obtained by polymerization of acrolein or by oxidation of a polyol.
• the invention thus relates to a phenolic resin, intended to be used massively or in a sizing composition for mineral or vegetable fibers. This resin results from the condensation, in the presence of a basic catalyst, of a polymer carrying aldehyde functions, phenolic compounds, amine and urea.
• the elaboration of a macromolecular compound bearing aldehyde functions is intended to overcome the use of molecular compounds with aldehyde function to reduce the volatility and toxicity of the aldehyde hardener.
• Phenoplasts are thermosetting materials obtained by polycondensation of a phenol and an aldehyde with removal of water and formation of a three-dimensional network. Phenol and formaldehyde are by far the most commonly used basic products, but some substituted phenols (cresol, resorcinol, etc.) can lead to particular resins.
• the Belgian Leo Baekeland conducted a systematic study of the polycondensation of phenol and formalin in relation to the pH and the molar ratio of the two reagents. He had the merit of modifying the properties of the condensate obtained, generally designated by the name of resin, by the addition of fillers and to foresee the uses thereof.
• phenoplasts are used by many industries in the form of resins (liquids, solutions and solids), molding materials, semi-finished products or composites. Applications in areas requiring good temperature stability, satisfactory fire behavior and low smoke emissions tend to develop, for example those composites in transport.
• Phenolic resins are well known for their use in the preparation of binders for glass fiber products, such as thermal and acoustic insulators, reinforcing glass fiber mats and printed circuit boards.
• US-A-3,932,334 discloses phenol-formaldehyde resoles which are simultaneously soluble in water and heat-curable, as well as binding systems based on these resols to be used to bind glass fibers to produce products such as insulating webs.
• other components such as other resins, monomers and additives are also added in addition to the water-soluble phenol-formaldehyde resin.
• Substantial proportions of nitrogen resins such as urea-formaldehyde and melamine-formaldehyde resins, and / or monomers such as urea, melamine and dicyandiamide, which are condensable with phenol-formaldehyde resins, may be added.
• a heat input volatilises the aqueous solvent and hardens the binder.
• These resins are obtained by condensation of phenol and formaldehyde, in the presence of a basic catalyst, in a formaldehyde / phenol molar ratio generally greater than 1 so as to promote the reaction between phenol and formaldehyde and to reduce the phenol content. residual in the resin. The residual content of formaldehyde and phenol in the resin remains high.
• Formaldehyde is thus an example of a substance of very high concern on the trade union list of priority substances in the REACh Regulation. It is mainly used for the manufacture of various types of resins (urea-, phenol- and melamine-formaldehyde) for the wood and paper sector, in the production of plastics, coating materials and in the plastics industry. textile finish. It is also used as a disinfectant and preservative in many applications.
• Global production of formaldehyde is about 21 million tons per year. Occupational exposures to formaldehyde therefore concern a wide variety of trades and industries - more than one million European workers are exposed to formaldehyde, including 200,000 in France.
• Formaldehyde is classified as a carcinogen of category 1 (carcinogenic to humans) by IARC (International Agency for Research on Cancer) and remains a Category 3 carcinogen with the risk phrase R40 at the European level.
• IARC International Agency for Research on Cancer
• Category 3 carcinogen with the risk phrase R40 at the European level.
• phenoplast resins be made from hardeners free of free formaldehyde or released during processing or use.
• EP0148050 discloses adding to the resin a sufficient amount of urea which reacts with free formaldehyde to form urea-formaldehyde condensates to reduce the amount of residual formaldehyde.
• the resin obtained contains phenol-formaldehyde condensates and urea-formaldehyde, has a free formaldehyde and free phenol content, expressed as total liquid weight, less than or equal to 3% and 0.5%, respectively, and has a water dilutability of at least 1000%. If the amount of residual phenol is acceptable, however, the amount of residual formaldehyde is too high to meet current regulatory constraints.
• US5030507 discloses a formaldehyde-free copolymer binder prepared from an emulsion of (meth) acrylic acid, styrene, acrylonitrile or vinyl acetate and an isocyanate.
• US6426121 contemplates the use of polyaldehyde hardener but actually only describes the use of telechelic dialdehyde, glyoxal and glutaraldehyde. But these two compounds are toxic or sensitizing.
• US Pat. No. 5,032,330 relates to a process for producing binders based on tannins without formaldehyde but with silica SiO 2 as coupling agent.
• US 6043350 relates to a process for producing binders based on tannins and paraformaldehyde and ammonium salts.
• EP0896008 relates to the binder composition containing pine bark and / or pecan tannins, paraformaldehyde and an ammonium salt of a weak acid.
• the formulations serve in particular as a binder for particle boards with high transverse tensile strength, good water resistance and low formaldehyde emission.
• US3254038 relates to a process for producing binders based on tannins, phenolic resin and an alkali metal hydroxide.
• Patent EP0544927 relates to a process for producing an adhesive composition comprising an isocyanate, a phenol-formaldehyde resin and a tannin. This composition is useful for the manufacture of plywood used outdoors.
• (k): The patent EP0648807 relates to the preparation of binders based on tannins and weakly acid coumpounds. These new binders are high temperature curable and compatible with cellulosic materials. They are suitable for the manufacture of wood-based materials such as particle board.
• (I): EP0639608 relates tannin-based thermosetting binders and a substance that releases formaldehyde under the action of heat. They are intended for cellulosic materials.
• (m): US2590760 relates to the production of resins based on tannin, sulfuric acid, acetone and potassium cyanide.
• US 4045386 relates to a formulation of binders based on an alkaline solution of bark containing tannins and an aldehyde.
• WO058843 relates to a formulation of binders based on a tannin, an amine compound (urea, monomethylol urea or dimethylol urea), an aldehyde (formaldehyde, paraformaldehyde or acetaldehyde).
• This object is achieved by the present invention which relates to the use of a macromolecular hardener bearing aldehyde functions in the production of phenolic resins with phenolic compounds.
• This macromolecular hardener carrying aldehyde functional groups is obtained, without the use of formaldehyde, by polymerization of acrolein or by controlled oxidation of a polyol, of natural origin or of synthesis. Quite unexpectedly, given the reactivity of the aldehydes, it has been found that macromolecular hardeners carrying aldehyde functions are likely to react much faster than other aldehydes.
• the polymer bearing aldehyde functional groups used as a hardener for phenolic compounds can be obtained in two ways: the polymerization of acrolein or the controlled oxidation of a polyol.
• Acrolein can be obtained by catalytic reduction of glycerol, a natural compound derived from oleaginous biomass. We have therefore polymerized acrolein to synthesize a poly (acrolein) bearing aldehyde reactive functions.
• Acrolein is a very reactive monomer that can polymerize anionically, cationically or radically 1 "The characteristics of the polymers synthesized by these different methods are very variable. The radical polymerization mobilizes exclusively the vinyl function by addition 1 -2, while ionic polymerizations occur mainly by the 3-4 addition to the carbonyl group, the third possibility of addition 1 -4 is less frequently encountered, these sequences are summarized in Scheme 1.
• the ionic polymerization of acrolein mainly mobilizes the carbonyl function, but the additions on the vinyl function and on the two functional groups also occur. Because of the spacing between the pendant aldehyde functions, condensation does not occur, solubility problems do not arise and the polymers, shown in Scheme 2, are soluble in water and organic solvents. It should be noted that the ratio m / n can be modified, in particular by varying the reaction temperature, the polarity of the solvent or the strength of the base.
• the starting oligomer can also be derived from renewable resources. Indeed, there are many access routes to polyols from biomass (oil, glycerol ). It is therefore a question of preparing polyols (2 to 20 hydroxyl groups) or of using natural polyols and of oxidizing them in a controlled manner to obtain aldehydes. ox
• polystyrene resin poly(allyl alcohol), poly (hydroxyethyl acrylate), polyethers (hydroxyethylvinylether up to hydroxybutylvinylether).
• polyethers such as ⁇ - ⁇ dihydroxypolyethers (polyglycerol, polyethylene glycol) can also be used.
• the oxidation of the polyol is carried out in water at 0 ° C. with an oxidant.
• the polymer obtained is soluble in water and has pendant aldehyde functions.
• the oxidation is most often carried out in an aqueous medium at room temperature with only 1 mol% (or less) of TEMPO in the presence of hypohalite (eg NaOCl) as cocatalyst and requires relatively short reaction times.
• hypohalite eg NaOCl
• phenolic compounds can be of synthetic or natural origin.
• the invention also relates to the following reagents: natural phenolic compounds, which are generally subdivided into simple phenols, phenolic acids (benzoic or cinnamic acid derivatives) and coumarins, into naphthoquinones, into stilbenoids (two 2C-linked C6 rings) , in flavonoids, isoflavonoids and anthocyanins (C6-C3-C6 structure) and in polymerized forms: lignans, lignins, condensed tannins and hydrolysable tannins.
• These basic carbon skeletons are derived from the secondary metabolism of plants, developed by the shikimate pathway. These are molecules containing at least one benzene ring and hydroxyl groups.
• Polymerized forms of the phenolic compounds may be depolymerized prior to use.
• the condensed tannins or proanthocyanidins
• the condensed tannins are depolymerized hot in an alcoholic medium in the presence of acid and a nucleophilic reagent ( x Xl x " Xl " XIV ).
• This nucleophilic reagent reacts on the higher units and extension units, which have been released as carbocations by acid-catalyzed rupture of the interflavanic bonds (Scheme 4).
• the nucleophilic reagent is a compound having a thiol function (such as, for example, oc-thiol toluene, thioglycolic acid, cysteine or cysteamine) is a monoaromatic phenolic compound such as phloroglucinol or resorcinol.
• a thiol function such as, for example, oc-thiol toluene, thioglycolic acid, cysteine or cysteamine
• a monoaromatic phenolic compound such as phloroglucinol or resorcinol.
• One of the inventive foundations of these new phenoplast resins is to use a polymer carrying reactive aldehyde functions as a hardener.
• the polymer corresponds to a macromolecular chain with a degree of polymerization greater than two, carrying at least two aldehyde functions.
• Another remarkable advantage of the selected pathway is that it does not use formaldehyde.
• the polymer obtained was characterized by steric exclusion chromatography in tetrahydrofuran THF using a polymethyl methacrylate PMMA calibration.
• the mixture is brought to 45 ° with stirring, then is regularly introduced in 30 minutes, maintaining the temperature at 45 q C, 2.6 g of 50% aqueous solution of sodium hydroxide (ie 1 1 mol OH - per 100 moles of initial phenol).
• the temperature is then raised regularly from 45 to 70% over 30 minutes and maintained at 70% for 80 minutes until the phenol conversion is 93%.
• the resin is in the appearance of a clear aqueous composition having a dilutability in water at 20 C q, infinite after more than 8 days.
• the free phenol content is 0.8%.
• the resin does not contain free formaldehyde.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Phenolic Resins Or Amino Resins (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (17)

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• 2009
  • 2009-11-20 FR FR0905594A patent/FR2952937B1/fr active Active
• 2010
  • 2010-11-19 WO PCT/FR2010/052465 patent/WO2011061456A1/fr not_active Ceased
  • 2010-11-19 EP EP10799087.1A patent/EP2501735B1/fr active Active
  • 2010-11-19 JP JP2012539392A patent/JP5814250B2/ja active Active
  • 2010-11-19 US US13/510,624 patent/US9040650B2/en active Active
• 2015
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