WO2005007721A1

WO2005007721A1 - Prepolymer mixture for the production of polyurethane foam in aerosol container, with the low content of isocyanate monomer

Info

Publication number: WO2005007721A1
Application number: PCT/PL2004/000047
Authority: WO
Inventors: Zbigniew Resler; Tomasz Pawlus
Original assignee: Orion Sp. Z O.O.
Priority date: 2003-07-21
Filing date: 2004-06-22
Publication date: 2005-01-27
Also published as: PL361365A1

Abstract

The prepolymer mixture for the production of polyurethane foam in the aerosol container with the low content of isocyanate monomer, consisting of polyurethane prepolymer with the content of NCO groups amounting to 4% to 15% by weight, known auxiliary substances, blowing agent and flame retardants. The mixture is characterized by the content of polyurethane prepolymer based on 4,4'-diphenylmethane diisocyanate or/and 2,4-diphenylmethane diisocyanate, that is also called MDI, with the content of isocyanate monomer below 0,1 % by weight or below 0,3% by weight in terms of prepolymer component.

Description

Prepolymer Mixture for the Production of Polyurethane Foam in Aerosol Container, with the Low Content of Isocyanate Monomer.

The subject of invention is the prepolymer mixture for the production of polyurethane foam in the aerosol container, with the low content of isocyanate monomer. The prepolymer mixture after the invention serves the production of polyurethane foams that are used for the filling of gaps and empty spaces. The main domain of application is the assembly and filling of gapsbetween the windows or doors and the wall, filling of pipe penetrations and other applications in the building engineering and other technical branches. There are known the one-component polyurethane foams that are also called the IK foams. These originate during the use by the release of prepolymer mixture from the aerosol container with the help of propellant gas. The IK foams with the density of 10-30 g/1, hardened under the influence of air moisture can be afterwards worked mechanically. The two-component polyurethane foams are also called the 2K foams. In this case for the hardening of prepolymer mixture the second component containing the hydroxyl group should be added directly before the production of foam. The density of 2K foams amounts to 10-100 g/1. There is also possible the transitory form between the IK and 2K foams. It is produced by the addition of component containing the hydroxyl groups to the prepolymer before the release, but the quantity of additive is insufficient to react with all isocyanate groups. The density of this foam, known as 1,5K foam, amounts to 10-60g/l. The prepolymer mixtures for the production o^f polyurethane foams contain the prepolymer component with the minimum content of NCO reactive groups. The prepolymer is the polymer with the appropriate viscosity, containing the terminal NCO groups. The mixture contains large quantities of isocyanate monomer. The proper isocyanates are for example tolylene diisocyanate called TDI, hexane 1,6-diisocyanate called HDI, isophorone diisocyanate called IPDI, or 4,4'- diphenylmethane diisocyanate called MDI, that is used not only in the form of raw material, but also in the form of pure isomers 2,4 and 4,4' or in the form of their mixture. Also both isomers of TDI can be used separately or in the mixture. For the production of prepolymer the isocyanates are subjected to the reaction with the poly ethers, polyesters or polyalcohols containing the hydroxyl groups, but one should take care of the proper viscosity of prepolymer. The polyurethane prepolymers that can be used for the production of polyurethane foams in the aerosol containers have the residual content of non-reacted isocyanate monomer, amounting up to 40%. This residual content depends on the production conditions. The isocyanate monomers in spite of their low volatility are dangerous considering their toxicity and there is an obligation to mark their presence. The monomer isocyanate groups are highly reactive and in living organisms their irritating and toxic action can be observed. In the case of release of prepolymer mixtures with carrier gases from the aerosol containers there is a danger, especially when non- professionally used, that the aerosol will be produced. This may result in skin and airways contact with the isocyanate monomer. It is the undesirable effect. But it should be emphasised that the polyurethane foams have proven highly correct. Apart from the widely known good insulating properties these foams have some more favourable properties that introduced their application to many useful purposes. These properties are, among others, exceptionally easy handling, fast hardening, good adhesion to the existing base, good characteristics of complete filling and foaming and even the good tolerance of living organisms in relation to the hardened product. In fact the ready polyurethane foams can be classified as the non-toxic products. There is a lot of measures that reduce the toxicity of traditional foaming prepolymer mixtures in the aerosol containers, in particular by the selection of specific isocyanates to the production of prepolymers and by the reduction of monomer fraction in the prepolymer mixtures. Globally the application these measures was quite successful, but it does not solve the above mentioned problem of admission, because the mitigated mixtures of this type still contain the isocyanate monomer. Therefore it would be desirable to have at our disposal the prepolymer mixtures producing the foams with the properties of traditional polyurethane foams, but without the monomer isocyanate groups in the prepolymer. Apart from this there should be the possibility to release such prepolymer mixtures of the traditional aerosol containers, that means without the necessity to change the production and dosage technology. If the hardening of foams is realised by means of water contained in the atmospheric air or added, then during the reaction with isocyanate groups there is released CO2 conditioning or supporting the foam formation process. According to the needs the foam formation process can be supported or realised by means of carrier gases. As the carrier gases there are currently used mostly the fluoride hydrocarbons remaining in room temperature in the gaseous state, hydrocarbons or/and dimethyl ether, as well as CO2, N2 or N2O. The prepolymer mixtures for the production of polyurethane foams in the aerosol containers consist of many components. First it is the proper prepolymer that is produced of one isocyanate and polyalcohol during the release. The prepolymer in the past and at present contains the reactive isocyanate groups that react with the reticulating component or water and form the polymer having the foaming properties. Moreover these prepolymer mixtures contain the additives such as for example the flame retardants, cell-stabilizers, plasticizers, agents for the control of viscosity or other important properties and the catalysts. These additives mostly do not react with the isocyanate groups of prepolymer, but there are also some exceptions here. In such cases these additives can become the product component by reaction without loosing their function. We can here mention the polyalcohols containing the halogen groups that are used for the production of prepolymers and have the fϊreproofing properties. The subject of invention is most approximated by „The Prepolymer Mixture for the Production of Insulating Polyurethane Foams" that is consistent with the Polish Patent Description No 175824. The prepolymer mixture consists of the prepolymer component containing at least one polyurethane prepolymer, produced as a result of the reaction of polyisocyanates with the compounds containing the hydroxyl groups, with the content of NCO groups amounting to 4% to 20% by weight, known auxiliary substances and blowing agent. This mixture is characterised by the content of polyurethane prepolymer based on hexamethylene-l,6-diisocyanate, tolylene diisocyanate, or isophorone diisocyanate or their mixtures with the other polyisocyanates, and the content of isocyanate monomer amounts to less than 2% by weight in terms of prepolymer component. The essence of invention is the prepolymer mixture for the production of polyurethane foam in the aerosol container, with the low content of isocyanate monomer, consisting of polyurethane prepolymer with the content of NCO groups amounting to 4% to 15% by weight, known auxiliary substances, blowing agent and flame retardants. The mixture is characterised by the content of polyurethane prepolymer based on 4,4'- diphenylmethane diisocyanate or/and 2,4- diphenylmethane diisocyanate, that is also called MDI, with the content of isocyanate monomer below 0,1% by weight or below 0,3% by weight in terms of prepolymer component. The mixture can contain 4,4'- diphenylmethane diisocyanate with the content of isocyanate monomer below 0,3%» by weight, or the polyurethane polymer based on 2,4- diphenylmethane diisocyanate with the content of isocyanate monomer below 0,1% by weight in terms of prepolymer component, or based on 2,4- diphenylmethane diisocyanate with the content of isocyanate monomer below 0,3% by weight. The mixture can also contain the polyurethane prepolymer based on the mixture of isomers of 4,4'- and 2,4- diphenylmethane diisocyanate with the isocyanate monomer content below 0,3 % by weight, or the polyurethane prepolymer acquired from the mixture of diphenylmethane diisocyanate with the content of isocyanate monomer below 0,3% by weight and polyurethane prepolymer based on diphenylmethane diisocyanate and PPG-type polyol (polypropylene glycol) with the molecular weight of 450 - 1000 and with the content of isocyanate monomer below 0,1% by weight, or the polyurethane prepolymer acquired from the mixture of diphenylmethane diisocyanate with the content of isocyanate monomer below 0,3% by weight and polyurethane prepolymer based on diphenylmethane diisocyanate and polyether polyol with the molecular weight of 450 - 1000 and with the content of isocyanate monomer below 0, 1 % by weight, or the polyurethane prepolymer acquired from the mixture of diphenylmethane diisocyanate with the content of isocyanate monomer below 0,3% by weight and polyurethane prepolymer based on diphenylmethane diisocyanate and polyester polyol with the molecular weight of 400 - 1000 and with the content of isocyanate monomer below 0,1% by weight, or the mixture of diphenylmethane diisocyanate with the content of isocyanate monomer below 0,3% by weight and hexane 1,6-diisocyanate HDI in form of dimer or trimer. To achieve the objective according to the invention, that means to acquire the polymer mixture with the content of isocyanate monomer below 0,1%» by weight, because this value allows, according to the valid regulations, to classify the product as non-dangerous for the living organisms, there was used the polyurethane prepolymer with the content of monomeric MDI below 0,1% by weight. There was also applied the demonomerised polymeric diphenylmethane diisocyanate with the monomer content below 0,3% by weight. These substances were acquired by the distilling off the isocyanate monomer. The viscosity of prepolymer with the content of monomeric isocyanate below 0,1% by weight amounts to 5000-50000 mPas (50°C) when the content of NCO groups amounts to 6% to 9% by weight. It should be mentioned here that the viscosity vary depending on the use of diphenylmethane diisocyanate isomer (2,4 or 4,4') and on the used polyether polyol. The lowest viscosity was obtained when the 2,4 isomer of diphenylmethane diisocyanate and polyether with the molecular weight of 1000 were used. The viscosity of demonomerised polymeric diphenylmethane diisocyanate amounts to 3000 mPas (50°C) when the content of NCO groups amounts to 29% by weight and the content of isocyanate monomer below 0,3% by weight. According to the invention, in order to release the prepolymer mixture from the aerosol container, the prepolymer mixture contains the propellant components, for example the fluoride hydrocarbons, hydrocarbons or/and ethers that boil at low temperatures. In particular there are preferred the fluoride hydrocarbons R134a and R152a, pure hydrocarbons, propane, butane and isobutane, as well as dimethyl ether. C0₂ or N₂ can also be present there as the propellant components. There is possible any arrangement of these gases. In the recipes for the aerosol containers there are preferred the contents of propellant gas amounting to 5% by weight to 40% by weight in relation to the whole prepolymer mixture. The gas content, that under the existing pressure conditions can not condense, should be calculated to obtain the pressure of 6 to 10 bar according to the valid rules for the aerosol containers. According to the invention the prepolymer mixture contains the ordinary additives for this sphere of application, such as for example the flame retardants, controllers of cell structure, foam stabilizers, viscosity controllers and plasticizer. As the flame retardants there can be used the well-known in this branch the phosphorus- containing compounds, in particular the phosphates, for example the triethyl phosphate called also TEP or trichloropropyl phosphate called TCPP. These compounds are at the same time the softening and viscosity-controlling properties that is especially important in the use of prepolymer components having the high viscosity. In particular there are preferred the arrangements of phosphates on the one hand and polyester polyols on the other one. These compounds allow to produce the B2-class foams according to DIN 4102. The other flame retardants that can be mentioned here are the halogenised polyester polyalcohols and polyether polyalcohols, for example the attainable brominated polyether polyalcohol. This compound is at the same time the component of polyalcohol used for the production of prepolymer. As the controllers of cell structure there are used the ordinary compounds based on the silicones. The stabilizing agents are the ordinary silicon stabilizers. It is purposeful to add the catalyst to the consistent with the invention prepolymer mixture in order to support the reticulation reaction. As the catalytic agents there can be used the amine compounds, such as triethylenediamine, tetramethyliminodipropylamine and dimorpholinoether. Other suitable catalytic agents are based on the organic or inorganic compounds of heavy metals. For the 1,5K and 2K foams the catalyst with the reticulating agent are stored separately from the prepolymer mixture, or in the reticulating agent tube that is released to activate the prepolymer mixture. Water is used as the reticulating agent. As the catalyst there can be used the above mentioned compounds. Next the invention refers to the application of above mentioned prepolymer mixtures to the formation of foams produced of these foam materials as well as the aerosol containers of IK, 1,5K and 2K type, containing these mentioned prepolymer mixtures, possibly with one or some more, separate components. The mixture according to the invention is shown in the example of realisation:

Prepolymer: MDI prepolymer with the NCO content of 6,5% by weight produced by the reaction of 4,4'- diphenylmethane diisocyanate with the polypropylene glycol with the molecular weight of 900 g/mol and the reduction of excessive monomeric isocyanate below the level of 0,1% by weight. Polymeric MDI: demonomerised polymeric diphenylmethane diisocyanate with the monomer content below 0,3% by weight. Polyol: polyester polyol with the molecular weight of 400 - 800 g/mol. Plasticizer: triethyl phosphate or trichloropropyl phosphate. HDI: hexane 1,6-diisocyanate in form of dimer or trimer. Reactive flame retardants: brominated polyether polyol. Stabilizer: silicone foam stabilizer. Catalyst: amine catalyst, organic or inorganic compound of heavy metals. Propellant gas: mixture of propellant gases R134a, propane, butane, isobutane and dimethyl ether. The prepolymer is placed in the aerosol container together with all additives. Next the valve is crimped and the content is gassed with the mixture of propellant gases and the whole container is shaken until the propellant gases are fully mixed with the prepolymer. The aerosol container gets warm because of inside reactions. After the room temperature is achieved we should shake the container and open the dosage valve. After the examinations the content of isocyanate monomer in the received foams is less than 0,1% by weight. The parameters of received foams do not differ significantly from the known products containing more isocyanate monomer. Only the dust dry time and pre-treatment time are 30% longer in relation to the known products. The resistance parameters of acquired foams, such as tearing strength and elongation strength. The foams made in accordance with the presented examples have the medium- to fine-cell structure and are more elastic than the products known on the market. All these parameters cause that the obtained foams in the aerosol containers, with the content of isocyanate monomer below 0,1% by weight can easy replace the current products that considering their content of monomeric isocyanate are more dangerous and harmful, and in this connection have to be marked as the harmful substances. The after-mentioned table shows the other examples of realisation in accordance with the invention.

Claims

1. The prepolymer mixture for the production of polyurethane foam in the aerosol container with the low content of isocyanate monomer, consisting of polyurethane prepolymer with the content of NCO groups amounting to 4% to 15% by weight, known auxiliary substances, blowing agent and flame retardants that is characterized by the content of polyurethane prepolymer based on 4,4'- diphenylmethane diisocyanate or/and 2,4- diphenylmethane diisocyanate, that is also called MDI, with the content of isocyanate monomer below 0,1% by weight or below 0,3% by weight in terms of prepolymer component.

2. The prepolymer mixture as claimed in Claiml characterized by the fact that it is produced with the use of 4,4'- diphenylmethane diisocyanate, that is also called MDI, with the content of isocyanate monomer below 0,3% by weight.

3. The prepolymer mixture as claimed in Claiml characterized by the fact that it contains the polyurethane prepolymer based on 2,4- diphenylmethane diisocyanate, that is also called MDI, with the content of isocyanate monomer below 0,1% by weight in terms of prepolymer component.

4. The prepolymer mixture as claimed in Claiml characterized by the fact that it is produced with the use of 2,4- diphenylmethane diisocyanate, that is also called MDI, with the content of isocyanate monomer below 0,3% by weight.

5. The prepolymer mixture as claimed in Claiml characterized by the fact that it contains the polyurethane prepolymer based on the mixture of 4,4'- and 2,4- diphenylmethane diisocyanate with the content of isocyanate monomer below 0,3% by weight in terms of prepolymer component.

6. The prepolymer mixture as claimed in Claiml characterized by the fact that it is produced with the use of isomer mixture of 4,4'- and 2,4- diphenylmethane diisocyanate, that is also called MDI, with the content of isocyanate monomer below 0,3% by weight.

7. The prepolymer mixture as claimed in Claiml characterized by the fact that it contains the polyurethane prepolymer acquired from the mixture of diphenylmethane diisocyanate with the content of isocyanate monomer below 0,3%o by weight and polyurethane prepolymer based on diphenylmethane diisocyanate and PPG-type polyol (polypropylene glycol) with the molecular weight of 450 - 1000 and with the content of isocyanate monomer below 0,1%) by weight.

8. The prepolymer mixture as claimed in Claiml characterized by the fact that it contains the polyurethane prepolymer acquired from the mixture of diphenylmethane diisocyanate with the content of isocyanate monomer below 0,3%) by weight and polyurethane prepolymer based on diphenylmethane diisocyanate and polyether polyol with the molecular weight of 450 - 1000 and with the content of isocyanate monomer below 0,1% by weight.

9. The prepolymer mixture as claimed in Claiml characterized by the fact that it contains the polyurethane prepolymer acquired from the mixture of diphenylmethane diisocyanate with the content of isocyanate monomer below 0,3%o by weight and polyurethane prepolymer based on diphenylmethane diisocyanate and polyester polyol with the molecular weight of 400 - 1000 and with the content of isocyanate monomer below 0,1% by weight.

10. The prepolymer mixture as claimed in Claiml characterized by the fact that it is produced with the use of the mixture of diphenylmethane diisocyanate with the content of isocyanate monomer below 0,3% by weight and hexane- 1,6- diisocyanate, that is also called HDI, in form of dimer or trimer.