Patent Application
20230043804
The present invention is related to a reactive mixture comprising a Flame, Smoke and/or Toxicity (FST) retardant composition for making polyisocyanurate (PIR) and/or polyurethane (PUR) comprising foams.
More in particular, the present invention relates to an FST reducing composition comprising at least one compound having at least one ethylenically unsaturated moiety and optionally a radical initiator.
Halogen containing additives have been traditionally used as fire-retardants in organic resins. That is, the additive compounds contain either fluorine, chlorine or bromine. Brominated resins, which are the most common, are strong oxidizers. When exposed to heat, the weak bonds between the bromine and the rest of the resin's atomic structure cleaves and forms bromine radicals which interfere with extremely exothermic oxidation reactions and consequently inhibits the flame. While it is this reaction that gives brominated resins their fire-retardant properties, the bromine that is removed by this reaction then reacts with hydrogen to form hydrogen bromide (HBr). If the brominated resin is exposed to more and/or hotter flames, HBr density can increase. The resulting smoke is considerably more toxic than smoke from nonhalogenated resins.
In rigid polyurethane (PU) foams, for example, TCPP (trichloro propyl phosphate) is widely used. In many PU applications there have recently been restrictions proposed by countries such as Canada for uses in the furniture and bedding applications. Similarly, efforts are ongoing by the U.S. Environmental Protection Agency (EPA). The US Consumer Product Safety Commission (CPSC) is evaluating the potential regulation or even considers banning organo-chlorinated substances as fire retardants. The European Chemicals Agency (ECHA) has opened a public consultation in view of a restriction of TCEP, TCPP and TDCP in PU flexible foam for children articles and residential furniture and it could be broadened to other applications. Further, there is an increasing pressure on flame retardants by promoting “flame retardant free articles”. In California, for example, there is a push for fire retardant free insulation boards.
Seen the recent developments there is a need to develop new solutions that not only improve the flame retardance and flame resistance of polyisocyanurate (PIR) and/or polyurethane (PUR) comprising materials but also reduce the smoke and toxicity. These alternative solutions and/or compounds should not rely on TCPP or organo-halogen substances and should be suitable for use as additives in the reactive mixture used for making polyisocyanurate (PIR) and/or polyurethane (PUR) comprising materials and which do not have a negative impact on the properties of the final obtained PIR and/or PUR comprising material. Said compounds are herein referred to as Flame, Smoke and Toxicity (FST) reducing compounds.
The goal of the invention is to provide a Flame, Smoke and/or Toxicity (FST) retardant composition for use in a reactive mixture for making polyisocyanurate (PIR) and/or polyurethane (PUR) comprising materials thereby avoiding or at least minimizing the use of state of the art organo halogen fire retardants and further improving the fire retardancy in said materials when exposed to fire.
The goal is achieved by adding the Flame, Smoke and/or Toxicity (FST) retardant composition of the invention to a reactive mixture used to make the PIR/PUR comprising materials.
Surprisingly we have found that certain ethylenically unsaturated compounds optionally in the presence of a radical initiator can be used as additives in PIR/PUR comprising materials to reduce the Flame, Smoke and Toxicity generation from said PIR/PUR comprising materials when exposed to fire.
In the context of the present invention the following terms have the following meaning:
The present invention will be described with respect to particular embodiments.
It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, steps or components as referred to, but does not preclude the presence or addition of one or more other features, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.
Throughout this specification, reference to “one embodiment” or “an embodiment” are made. Such references indicate that a particular feature, described in relation to the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, though they could. Furthermore, the particular features or characteristics may be combined in any suitable manner in one or more embodiments, as would be apparent to one of ordinary skill in the art.
It is to be understood that although preferred embodiments and/or materials have been discussed for providing embodiments according to the present invention, various modifications or changes may be made without departing from the scope and spirit of this invention.
The present invention provides a Flame, Smoke and/or Toxicity (FST) retardant composition for use in reactive mixtures for making polyisocyanurate and/or polyurethane (PIR/PUR) comprising material having improved Flame, Smoke and/or Toxicity (FST) retardancy thereby avoiding or at least minimizing the use of state of the art organo halogen fire retardants.
It has been surprisingly observed that the addition of well-defined and selected compounds having ethylenically unsaturated moieties are very suitable as Flame, Smoke and/or Toxicity (FST) retardant compounds in a PIR/PUR comprising material.
According to the invention, these well-defined compounds are added as a Flame, Smoke and/or Toxicity (FST) retardant composition to a reactive mixture for making a PIR/PUR comprising material.
The invention therefore discloses a well-defined class of compounds having ethylenically unsaturated moieties that will act as Flame, Smoke and/or Toxicity (FST) retardant compounds in a PIR/PUR comprising material when exposed to fire. This well-defined class of compounds is chosen such that these compounds having ethylenically unsaturated moieties will maintain—after the process of making the PIR/PUR material—at least 10 wt % of non-polymerized ethylenically unsaturated moieties based on the total weight of all compounds originating from said compounds having at least one ethylenically unsaturated moiety in the PIR/PUR comprising material. This implies that after the process of making the PIR/PUR comprising material, at least 10 wt % of the total amount of compounds having ethylenically unsaturated moieties added still have non-polymerized ethylenically unsaturated moieties.
The well-defined class of compounds having ethylenically unsaturated moieties are selected such that after the process of making the PIR/PUR comprising material, at least 10 wt %, preferably 10 wt % up to 90 wt %, more preferably 20 wt % up to 80 wt % and more preferably 30 wt % up to 70 wt % of the total amount of compounds having ethylenically unsaturated moieties added have non-polymerized ethylenically unsaturated moieties.
The Fire, Smoke and Toxicity retardant (FST) composition (also referred to herein shortly as Fire retardant composition) according to the invention for use in a reactive mixture for making a polyisocyanurate and/or polyurethane (PIR/PUR) comprising material is comprising:
The invention therefor discloses a reactive mixture for making a polyisocyanurate and/or polyurethane (PIR/PUR) comprising material, said reactive mixture comprising:
According to embodiments, the onset temperature for radical polymerization (Tonset) of the combination of the ethylenically unsaturated compound and the radical initiator is 2° C. up to 40° C., preferably 5° C. up to 30° C. and more preferably 5° C. up to 15° C. lower than the maximum reaction temperature achieved during the process for making the PIR/PUR material (reaction exotherm (Treaction)).
According to embodiments, the Fire retardant (FST) composition according to the invention comprises predominantly compounds having at least one ethylenically unsaturated moiety and having a number average equivalent weight<160 g/mol, preferably <120 g/mol.
According to embodiments, the Fire retardant (FST) composition according to the invention comprises at least 75 wt %, preferably at least 85 wt %, more preferably at least 90 wt % of compounds having at least one ethylenically unsaturated moiety and having a number average equivalent weight<160 g/mol, preferably <120 g/mol based on the total weight of the FST composition.
The well-defined class of compounds having ethylenically unsaturated moieties according to the invention preferably have an onset temperature for radical polymerization (Tonset) of the ethylenically unsaturated compound which is preferably 2° C. up to 40° C. lower than the maximum reaction temperature achieved during the process for making the PIR/PUR comprising material (reaction exotherm (Treaction)).
In case a radical initiator is used in addition to the compounds having ethylenically unsaturated moieties, the onset temperature for radical polymerization (Tonset) of the ethylenically unsaturated compound in the presence of the radical initiator (if present) is preferably 2° C. up to 40° C. lower than the maximum reaction temperature achieved during the process for making the PIR/PUR comprising material (reaction exotherm (Treaction)).
According to embodiments, the onset temperature for radical polymerization (Tonset) of the compounds having ethylenically unsaturated moieties with or without the radical initiator is preferably 2° C. up to 40° C., more preferably 5° C. up to 30° C. and most preferably 5° C. up to 15° C. lower than the maximum reaction temperature achieved during the process for making the PIR/PUR material (reaction exotherm (Treaction)). The onset temperature for radical polymerization (Tonset) of the compounds having ethylenically unsaturated moieties with or without the radical initiator may be 5° C.-10° C., 10° C.-15° C., 15° C.-20° C., 20° C.-25° C., 25° C.-30° C., 30° C.-35° C. lower than the maximum reaction temperature achieved during the process for making the PIR/PUR material.
According to embodiments, the compounds having at least one ethylenically unsaturated moiety comprise at least 1 ethylenically unsaturated moiety, preferably 2 up to 8 ethylenically unsaturated moieties.
According to embodiments, the compound having at least one ethylenically unsaturated moiety is a monomeric compound.
According to embodiments, the compounds having at least one ethylenically unsaturated moiety is selected from an acrylate, methacrylate, acrylic acid, methacrylic acid allyl alcohol and/or maleic acid and derivatives or mixtures thereof.
According to embodiments, the compounds having at least one ethylenically unsaturated moiety is selected from pentaerythritol tri-acrylate (PETA), pentaerythritol tetra-acrylate (PETRA), ethylene glycol diacrylate (EGDA), hydroxyethyl acrylate (HEA), diethylene glycol diacrylate (DEGDA), hydroxyethyl methacrylate (HEMA), ethylene glycol dimethacrylate (EGDMA) and diethylene glycol dimethacrylate (DEGDMA) and mixtures thereof.
According to embodiments, the radical initiator compound is selected from benzoyl peroxide, t-butyl peroxybenzoate (Luperox® P), di-t-butyl peroxide (Luperox® DI), tert-butyl-hydroxyperoxide (Luperox® TBH 70X) and mixtures thereof. A radical initiator which is active at too low temperatures (e.g. too close to room temperature) is to be avoided as it will likely result in poor foam flow on top of handling safety issues.
According to a preferred embodiment, the compound having at least one ethylenically unsaturated moiety is selected from PETRA (Penta Erythritol Tetra Acrylate, see formula I) which is a tetrafunctional acrylate without reactive OH groups and having a molecular weight of 352 g/mol (equivalent molecular weight of 88 g/eq).
According to another preferred embodiment, the compound having at least one ethylenically unsaturated moiety is selected from PETRA (PentaErythritol TetraAcrylate, see formula I) and the radical initiator used in combination with PETRA is selected from Luperox® DI (tert-Butyl peroxide, see formula II) with a 10 h half-life temperature of 121° C. or Luperox® P (t-butyl peroxybenzoate, see formula III) with a 10 h half-life temperature of 103° C.
According to a preferred embodiment, the compound having at least one ethylenically unsaturated moiety is further comprising at least one isocyanate reactive moiety. During the process of making the PIR/PUR comprising material the isocyanate reactive moieties may react with the isocyanate groups in the polyisocyanate compounds and the compound having at least one ethylenically unsaturated moiety will be incorporated (cross-linked) to the PIR/PUR matrix of the PIR/PUR comprising material.
According to embodiments, the compound having at least one ethylenically unsaturated moiety has a boiling point under atmospheric pressure higher than 150° C., preferably higher than 200° C.
According to embodiments, the amount of Fire retardant (FST) composition in the reactive mixture is such that the amount of compounds having at least one ethylenically unsaturated moiety in the reactive mixture is at least 2 wt % based on the total weight of all ingredients in the reactive mixture.
According to embodiments, the amount of compound having at least one ethylenically unsaturated moiety in the reactive mixture is in the range 2 wt % up to 30 wt %, preferably in the range 2 wt % up to 20 wt %, more preferably in the range 2 wt % up to 15 wt % calculated on the total weight of the reactive mixture.
According to embodiments, the amount of radical initiator compound(s) in the reactive mixture is in the range 0.01 wt % up to 1 wt %, preferably in the range 0.03 wt % up to 0.5 wt % calculated on the total weight of the reactive mixture.
According to embodiments, the amount of compounds having ethylenically unsaturated moieties according to the invention added to a reactive mixture used to make a PIR/PUR comprising material is in the range 2 wt % up to 30 wt %, preferably 2 wt % up to 20 wt %, more preferably 2 wt % up to 15 wt % based on the total weight of the reactive mixture used to make the PIR/PUR comprising material. Examples of preferred amounts of compounds having ethylenically unsaturated moieties added to a reactive mixture are 8 wt %, 9 wt %, 10 wt %, 11 wt % and 12 wt % based on the total weight of the reactive mixture used to make the PIR/PUR material.
According to embodiments, the amount of compounds having ethylenically unsaturated moieties according to the invention added to a reactive mixture used to make a PIR/PUR material is in the range 2 wt % up to 30 wt % based on the total weight of the reactive mixture and the PIR/PUR comprising material made using that reactive mixture comprises 0.2 wt % up to 27 wt % of compounds having at least one non-polymerized ethylenically unsaturated moiety based on the total weight of the PIR/PUR comprising material thereby taking into account that after the process of making the PIR/PUR comprising material 10 wt % up to 90 wt % of the total amount of compounds having ethylenically unsaturated moieties added will have non-polymerized ethylenically unsaturated moieties.
According to embodiments, the amount of compounds having ethylenically unsaturated moieties according to the invention added to a reactive mixture used to make a PIR/PUR comprising material is in the range 2 wt % up to 30 wt % based on the total weight of the reactive mixture and the PIR/PUR comprising material made using that reactive mixture comprises 0.4 wt % up to 24 wt % of compounds having at least one non-polymerized ethylenically unsaturated moiety based on the total weight of the PIR/PUR comprising material thereby taking into account that after the process of making the PIR/PUR comprising material, 20 wt % up to 80 wt % of the total amount of compounds having ethylenically unsaturated moieties added will have non-polymerized ethylenically unsaturated moieties.
According to embodiments, the amount of compounds having ethylenically unsaturated moieties according to the invention added to a reactive mixture used to make a PIR/PUR comprising material is in the range 2 wt % up to 30 wt % based on the total weight of the reactive mixture and the PIR/PUR comprising material made using that reactive mixture comprises 0.6 wt % up to 21 wt % of compounds having at least one non-polymerized ethylenically unsaturated moiety based on the total weight of the PIR/PUR comprising material thereby taking into account that after the process of making the PIR/PUR comprising material, 30 wt % up to 70 wt % of the total amount of compounds having ethylenically unsaturated moieties added will have non-polymerized ethylenically unsaturated moieties.
According to embodiments, the amount of compounds having ethylenically unsaturated moieties according to the invention added to a reactive mixture used to make a PIR/PUR comprising material is in the range 2 wt % up to 30 wt %, preferably in the range 2 wt % up to 20 wt %, more preferably in the range 2 wt % up to 15 wt % based on the total weight of the reactive mixture and the PIR/PUR comprising material made using that reactive mixture comprises 0.2 wt % up to 27 wt %, preferably 0.2 wt % up to 18 wt % and more preferably 0.2 wt % up to 13.5 wt % of compounds having at least one non-polymerized ethylenically unsaturated moiety based on the total weight of the PIR/PUR comprising material thereby taking into account that after the process of making the PIR/PUR comprising material, 10 wt % up to 90 wt % of the total amount of compounds having ethylenically unsaturated moieties added will have non-polymerized ethylenically unsaturated moieties.
According to embodiments, the polyisocyanate compounds according to the invention are selected from organic polyisocyanate compounds containing a plurality of isocyanate groups including aliphatic isocyanates such as hexamethylene diisocyanate and more preferably aromatic isocyanates such as m- and p-phenylene diisocyanate, tolylene-2,4- and 2,6-diisocyanates, diphenylmethane-4,4′-diisocyanate, chlorophenylene-2,4-diisocyanate, naphthylene-1,5-diisocyanate, diphenylene-4,4′-diisocyanate, 4,4′-diisocyanate-3,3′-dimethyldiphenyl, 3-methyldiphenylmethane-4,4′-diisocyanate and diphenyl ether diisocyanate, cycloaliphatic diisocyanates such as cyclohexane-2,4- and 2,3-diisocyanates, 1-methyl cyclohexyl-2,4- and 2,6-diisocyanates and mixtures thereof and bis-(isocyanatocyclohexyl-)methane and triisocyanates such as 2,4,6-triisocyanatotoluene and 2,4,4′-triisocyanatodiphenyl ether.
According to embodiments, the polyisocyanate compounds may be selected from mixtures of polyisocyanates. For example a mixture of tolylene diisocyanate isomers such as the commercially available mixtures of 2,4- and 2,6- isomers and also the mixture of di- and higher poly-isocyanates produced by phosgenation of aniline/formaldehyde condensates. Such mixtures are well-known in the art and include the crude phosgenation products containing mixtures of methylene bridged polyphenyl polyisocyanates, including diisocyanate, triisocyanate and higher polyisocyanates together with any phosgenation by-products.
Preferred polyisocyanate compositions of the present invention are those wherein the polyisocyanate is an aromatic diisocyanate or polyisocyanate of higher functionality in particular crude mixtures of methylene bridged polyphenyl polyisocyanates containing diisocyanates, triisocyanate and higher functionality polyisocyanates. Methylene bridged polyphenyl polyisocyanates (e.g. Methylene diphenyl diisocyanate, abbreviated as MDI) are well known in the art and have the generic formula I wherein n is one or more and in the case of the crude mixtures represents an average of more than one. They are prepared by phosgenation of corresponding mixtures of polyamines obtained by condensation of aniline and formaldehyde.
Other suitable polyisocyanate compounds may include isocyanate ended prepolymers made by reaction of an excess of a diisocyanate or higher functionality polyisocyanate with a hydroxyl ended polyester or hydroxyl ended polyether and products obtained by reacting an excess of diisocyanate or higher functionality polyisocyanate with a monomeric polyol or mixture of monomeric polyols such as ethylene glycol, trimethylol propane or butane-diol. One preferred class of isocyanate-ended prepolymers are the isocyanate ended prepolymers of the crude mixtures of methylene bridged polyphenyl polyisocyanates containing diisocyanates, triisocyanates and higher functionality polyisocyanates.
According to embodiments, the polyisocyanate compounds are selected from a toluene diisocyanate, a methylene diphenyl diisocyanate or a polyisocyanate composition comprising a methylene diphenyl diisocyanate or a mixture of such polyisocyanates.
According to embodiments, the one or more isocyanate reactive compounds include any of those known in the art for the preparation of polyisocyanurate and/or polyurethane comprising rigid foams. Of particular importance for the preparation of rigid foams are polyols and polyol mixtures having average OH values of from 50 to 1000 mg KOH/g, especially from 150 to 700 mg KOH/g, and hydroxyl (OH) functionalities of from 2 to 8, especially from 3 to 8. Suitable polyols have been fully described in the prior art and include polyether-based polyols which are reaction products of alkylene oxides, for example ethylene oxide and/or propylene oxide, with initiators containing from 2 to 8 active hydrogen atoms per molecule. Suitable initiators include: polyols, for example glycerol, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol and sucrose; polyamines, for example ethylene diamine, tolylene diamine (TDA), diaminodiphenylmethane (DADPM) and polymethylene polyphenylene polyamines; and aminoalcohols, for example ethanolamine and diethanolamine; and mixtures of such initiators. Other suitable polyols include polyester based polyols obtained by the condensation of appropriate proportions of glycols and higher functionality polyols with dicarboxylic or polycarboxylic acids. Still further suitable polymeric polyols include hydroxyl terminated polythioethers, polyamides, polyesteramides, polycarbonates, polyacetals, polyolefins and polysiloxanes.
According to embodiments, the PIR/PUR comprising material is a foamed material and the blowing agent may be selected from isobutene, dimethyl ether, water, methylene chloride, acetone, chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydrofluoroolefins (HFOs) and hydrocarbons such as pentane. The amount of blowing agent used can vary based on, for example, the intended use and application of the foam product and the desired foam stiffness and density. The blowing agent may be present in amounts from 0.5 to 60, more preferably from 1 to 45 parts by weight (pbw) per hundred weight parts isocyanate-reactive compounds (polyol).
According to embodiments, the PIR/PUR comprising material is a foamed material and the blowing agent comprises/contains water and the amount of water is preferably limited to amounts up to 15 pbw.
According to embodiments, the catalyst compound should be present in the reactive mixture in a catalytically effective amount, preferably the catalyst compound is present in amounts such that the number of catalyst equivalents over the number of isocyanate equivalents ranges from 0.001 to 0.4, preferably in an amount from 0.01 to 0.26, or from 0.01 to 0.24, or from 0.02 to 0.2.
According to embodiments, one or more polyurethane catalyst compounds suitable for use herein include, but are not limited to, metal salt catalysts, such as organotins, and amine compounds, such as triethylenediamine (TEDA), N-methylimidazole, 1,2-dimethylimidazole, N-methylmorpholine, N-ethylmorpholine, triethylamine, N,N′-dimethylpiperazine, 1,3,5-tris(dimethylaminopropyl)hexahydrotriazine, 2,4,6-tris(dimethylaminomethyl)phenol, N-methyldicyclohexylamine, pentamethyldipropylene triamine, N-methyl-N′-(2-dimethylamino)-ethyl-piperazine, tributylamine, pentamethyldiethylenetriamine, hexamethyltriethylenetetramine, heptamethyltetraethylenepentamine, dimethylaminocyclohexylamine, pentamethyldipropylene-triamine, triethanolamine, dimethylethanolamine, bis(dimethylaminoethyl)ether, tris(3-dimethylamino)propylamine, or its acid blocked derivatives, and the like, as well as any mixture thereof. The catalyst compound should be present in the reactive composition in a catalytically effective amount.
According to embodiments, one or more polyisocyanurate catalyst compounds (trimerization catalysts) suitable for use herein include but are not limited to quaternary ammonium hydroxides and salts, alkali metal and alkaline earth metal hydroxides, alkoxides and carboxylates, for example potassium acetate and potassium 2-ethylhexoate, certain tertiary amines and non-basic metal carboxylates. The catalyst compound should be present in the reactive composition in a catalytically effective amount.
According to embodiments, additionally state of the art fire retardant compounds such as triethylene phosphate or expandable graphite may be added to the reactive mixture used to make the PIR/PUR comprising material.
There are many different orders of adding and mixing the ingredients to form the PIR/PUR comprising material. One of skill in the art would realize that varying the order of addition of the compounds falls within the scope of the present invention.
According to embodiments, the Fire retardant (FST) composition may be added to the reactive mixture as a separate stream apart from the isocyanate composition and apart from the isocyanate-reactive composition.
The quantities of the one or more polyisocyanate compounds and the one or more isocyanate reactive compounds in the reactive mixture will depend upon the nature of the PIR/PUR comprising material to be produced and can be readily determined by those skilled in the art.
According to embodiments, the PIR/PUR comprising material made using the reactive mixture comprising the fire retardant (FST) composition of the invention is a polyisocyanurate (PIR) comprising foam, preferably a polyisocyanurate (PIR) comprising rigid foam made using a reactive mixture having an isocyanate index of 180 or higher, more preferably at an isocyanate index higher than 250 and the catalyst compound used in the reactive mixture is selected from at least one trimerisation catalyst.
According to embodiments, the PIR/PUR comprising material made using the reactive mixture comprising the fire retardant (FST) composition of the invention is a polyurethane (PUR) comprising foam, preferably a polyurethane (PUR) comprising flexible or semi-flexible foam made using a reactive mixture having an isocyanate index in the range 80-180, more preferably at an isocyanate index in the range 90-150 and the catalyst compound is selected from at least one polyurethane catalyst.
According to embodiments, the PIR/PUR comprising material using the reactive mixture comprising the fire retardant (FST) composition of the invention is a PIR/PUR comprising coating or adhesive.
According to embodiments, the PIR/PUR comprising material made using the reactive mixture comprising the fire retardant (FST) composition of the invention is a thermoplastic polyurethane (TPU) elastomer.
According to embodiments, the PIR/PUR comprising material made using the reactive mixture comprising the fire retardant (FST) composition of the invention is a PIR/PUR comprising foam with an apparent density<200 kg/m3 measured according to ISO 845 and having an open cell content below 50 wt %, preferably below 30 wt %, more preferably below 20 wt % by volume calculated on the total volume of the foam and measured according to ASTM D6226-10 (Open-cell Content by Pycnometer).
According to embodiments, the PIR/PUR comprising material made using the fire retardant (FST) composition of the invention may be used in thermal insulation, acoustic insulation and/or in structural panels such as construction thermal insulation foams or appliance thermal insulation foams in e.g. insulation panels.
Chemicals Used:
Fabrication of Polyurethane (PUR) Foams
Polyurethane foams were produced under free rise conditions by mixing under high shear with a Heidolph Mixer (˜2500 rpm) for 5 s the polyol blend (prepared beforehand, including all chemicals listed in the tables except the isocyanate) and the Isocyanate. A thermocouple with a diameter of 1.5 mm was placed at the middle of the foaming mold, 5 cm from the bottom to record the maximum exotherm temperature of the foaming process (Treaction) for the PUR formulations without added ethylenically unsaturated compounds (comparative examples 1 & 2). All PUR foams were stored in the fume hood overnight before being cut and characterized.
Synthesis of MDI-HEA & MDI-PETA
MDI was placed in a three-neck round flask equipped with a mechanical stirrer and nitrogen purge and 3 ppm thionyl chloride was added as trimerization inhibitor. The flask was heated at 70° C. in an oil bath and ethylenically unsaturated compounds comprising iso-reactive groups (HEA & PETA) were added dropwise in 30 minutes. The content of the flask was kept at 70° C. for 1 hour and the product was cooled to room temperature and stored in a closed container.
Kleinbrenner Test (B2 Test)
The Kleinbrenner test is used to compare the fire retardance (FR) performance of the different samples where a small flame is placed for 15 seconds against the bottom edge of the foam sample according to EN ISO 11925-2. A piece of foam (see 2 in FIG. 1) measuring 19 cm×9 cm×2.5 cm is cut. The test takes place inside a test chamber where the test specimen is mounted vertically. Once the foam has been placed in the metal holder (see 1 in FIG. 1), a 2 cm flame is placed at a 45° angle (see A in FIG. 1) at the bottom of the foam to ignite it.
The flame is kept there for 15 seconds to observe if and how high the foam burns. In order to compare FR performance of different systems, the Kleinbrenner test was used and foam samples were weighted before and after the test to determine mass loss percentage as an indicator of FR performance. Lower mass loss indicates better flame-retardant performance.
Determination of Onset of Polymerization (Tonset) of the Ethylenically Unsaturated Compounds Using DSC
In order to determine the onset of polymerization (Tonset) of the ethylenically unsaturated compounds, constant heating rate differential scanning calorimetry (DSC) were conducted. DSC investigations were performed using a Q2000 TA instrument. Ethylenically unsaturated compounds were premixed with the radical initiator (if applicable) and then 3-5 mg samples were sealed in hermetic aluminium pans and were heated from 0° C. to 280° C. at 10° C./min heating rate.
Determination of Conversion Ratio (α) of the Ethylenically Unsaturated Compounds Using DSC:
In order to determine the amount of un-reacted ethylenically unsaturated compounds (also referred to herein as compounds having non-polymerized ethylenically unsaturated moieties) in the PUR foams, isothermal differential scanning calorimetry (DSC) were conducted. DSC investigations were performed using a Q2000 TA instrument. 3 mg (±5%) ground samples were sealed in hermetic aluminium pans and were heated to 70° C. at 60° C./min heating rate and kept isothermally for 15 seconds. Then the temperature of the DSC furnace was equilibrated at 230° C. and kept isothermal for 20 minutes. The positive heat flow values are numerically integrated to estimate the total residual exotherm. The conversion ratios were calculated using equation 1:
Where α is the conversion ratio of the ethylenically unsaturated compounds (EUMs), REs is residual exotherm of the sample, REref is the residual exotherm of the reference foam (same formulation without the added ethylenically unsaturated compounds (EUMs)), CEUMs is the wt. % of the ethylenically unsaturated compounds (EUMs and REUMs is the residual exotherm of neat ethylenically unsaturated compounds (EUMs) plus 1 wt % Luperox® Di.
A conversion ratio (α) of 60% means that 40% of the ethylenically unsaturated compounds are non-polymerized ethylenically unsaturated compounds based on the total amount of ethylenically unsaturated compounds added to the reactive composition.
Table 1 summarizes the reactive compositions used and amounts of ingredients used in parts by weight (pbw) to fabricate the examples 1-12 according to the invention and comparative example 1 as well as Kleinbrener (B2) mass loss percentages, THR (Total Heat Release), PHRR (Peak Heat Release Rate) and TSP (Total Smoke Production) of the cone calorimetry tests, Treaction of the base formulation (comparative example 1) and Tonset of the ethylenically unsaturated compounds (EUMs) plus initiator if applicable.
Table 2 summarizes the reactive compositions used and amounts of ingredients used in parts by weight (pbw) to fabricate the examples 13-25 according to the invention and comparative example 1 as well as Kleinbrener (B2) mass loss percentages, Treaction of the base formulation (comparative example 1) and Tonset of the ethylenically unsaturated compounds plus initiator if applicable.
Table 3 summarizes the reactive compositions used and amounts of ingredients used in parts by weight (pbw) to fabricate examples 26 and 27 according to the invention and comparative example 3 as well as Kleinbrener (B2) mass loss percentages, Treaction of the base formulation (comparative example 2) and Tonset of the ethylenically unsaturated compounds plus initiator if applicable.
From Table 1 it is clear that all investigated acrylates (examples 1-12) reduce the mass loss in B2 compared to comparative example 1, both in presence and absence of thermal initiators. In the case of PETRA where various loads of radical initiator were tested (examples 1-4) and conversion ratio (α) were evaluated, the best result (lowest mass loss in B2 test) were herein obtained in the formulation in which the Tonset was 5° C. lower than the Treaction (0.1% Luperox® Di) with conversion ratio equal to ca. 59% (meaning that there is 41% of non-polymerized PETRA left based on the total amount of PETRA added to the reactive mixture). For all other acrylates used here (examples 5-12), adding 0.1% Luperox® Di reduced the mass loss of B2. Cone calorimetry results also show significant improvement in term of total smoke production (TSP) and peak heat release rate (PHRR).
From Table 2 it is clear that all investigated ethylenically unsaturated compounds in presence of 0.1% Luperox® Di, reduce the mass loss for B2, while in the case of TATA,—which in absence of radical initiator, has a significantly higher Tonset compared to the Treaction (216° C. vs. 130° C.)—it only improves the flame retardant performance in presence of Luperox® Di which reduces the Tonset to 136° C. which is closer to the Trenton (130° C.).
Table 3 shows that by replacing succinic anhydride (SA) with maleic anhydride (MA),—which has the similar structure as SA plus an ethylenically unsaturation—mass loss of B2 reduces from 17% for the comparative example 2 to ca. 9% for the example 26. Also, adding the thermal initiator, Luperox® Di, further reduces the mass loss to ca. 8% for the example 27.
| Number | Date | Country | Kind |
|---|---|---|---|
| 19219225.0 | Dec 2019 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/087586 | 12/22/2020 | WO |
