Foam manufacturing

Abstract

The present invention relates to a method for producing a foam, such as a foam insulation board, comprising the steps of: (i) providing foam reactants that react to form a foam; (ii) providing a blowing agent; (iii) expanding the foam reactants with the blowing agent to form a foam having gas cells defined therein during reaction of the foam reactants and having the blowing agent trapped within the gas cells; and (iv) recovering the blowing agent that is not trapped within the foam. Further, an apparatus for producing the foam is disclosed. The recovered blowing agent can be recycled / reused.

Description

[Technical field]

[0001] The present invention relates to a method for producing a foam, such as an insulating foam used for thermal insulation. Of particular interest is an insulating foam board. A method for the continuous production of the foam is also of interest. [Background technology]

[0002] The manufacture of foam boards or laminates is a well known process. They are typically produced as a continuous foam on a manufacturing line. The continuous form is cut to the desired length. Facers etc. may be applied during production. Generally reactants are mixed to form a foam. A blowing agent is used to expand the foam. The blowing agent becomes trapped within the foam, typically within the closed cells within the foam.

[0003] In such processes, it is desirable to maximize efficiency in production. For example, waste should be as little as possible and the foam produced must meet certain quality control standards. Given the bulk of the board that can be produced, any waste / material savings can be substantial. Summary of the Invention [Problem to be solved by the invention]

[0004] It is therefore desirable to provide a manufacturing method that minimizes waste in manufacturing. [Means for solving the problem]

[0005] In accordance with the present invention, there is provided a method for producing a foam, such as a foam insulation board, comprising the steps of: (i) providing foam reactants which react to form a foam; (ii) providing a blowing agent; (iii) using the blowing agent to expand the foam reactants during reaction of the foam reactants to form a foam having gas cells defined therein and the blowing agent trapped within the gas cells; and (iv) recovering the blowing agent not trapped within the foam.

[0006] The amount of blowing agent recovered can be quite substantial and can result in substantial savings. Also, said recovered blowing agent can be recycled and reused. For example, there is the potential for continuous recycling of blowing agent, such that blowing agent recovered from an earlier run can be used again in a later run. In this way, blowing agent losses are minimized and efficiency is increased.

[0007] Preferably, recovering the blowing agent comprises recovering the blowing agent as a gas. A blowing agent that is a liquid at or near room temperature is in a gaseous state when used to expand the foam. For example, the reaction of reactants to form the foam may occur in a heated enclosure.

[0008] Preferably, recovering the blowing agent comprises recovering the blowing agent as part of the gas mixture. Even if a single component blowing agent is used, it may not be possible to recover only the blowing agent. For example, water vapor and / or air may also be recovered.

[0009] Thus, the method of the present invention may further comprise the step of separating the blowing agent from the recovered mixture. Optionally, the blowing agent is recovered as a mixture with water vapor. In this case, the blowing agent may be separated from the water vapor, for example, when the blowing agent and water are in liquid form. Preferably, the blowing agent and water in liquid form are immiscible and therefore can be separated by gravity. For example, the mixture may be sent to a decanter, where it is fractionated into an aqueous fraction and an organic fraction.

[0010] It is desirable to reuse the recovered blowing agent in the production of foams, e.g., it is desirable to continually recover and continually reuse the blowing agent, and therefore the method of the present invention desirably further comprises the step of reusing the recovered blowing agent in the production of foams.

[0011] In the process of the present invention, the recovered blowing agent can be continuously reused in the production of foams by the methods described herein.

[0012] The blowing agent desirably comprises at least one of a hydrocarbon, a halogenated hydrocarbon, a hydrofluoroolefin, a chlorinated hydrofluoroolefin, or a combination thereof. Binary and ternary combinations of blowing agents are preferred.

[0013] The blowing agent may be comprised of a hydrocarbon such as a C3-C6 hydrocarbon, for example butane, for example isobutane, and / or pentane, preferably isopentane, or combinations thereof.

[0014] The blowing agent may additionally or alternatively be comprised of an unsaturated C3-C6 hydrocarbon, for example a butene, or a pentene, such as isopentene, or a combination thereof.

[0015] The blowing agent may additionally or alternatively comprise a hydrofluoroolefin (HFO).

[0016] The blowing agent may be comprised of a chlorinated hydrofluoroolefin, such as 1-chloro-3,3,3-trifluoropropene (1233zd) or 1-chloro-2,3,3,3-tetrafluoropropene (1224yd), or a combination thereof.

[0017] The blowing agent may additionally or alternatively comprise a halogenated hydrocarbon such as isopropyl chloride.

[0018] The blowing agent may be a mixture of at least two different blowing agents, for example, the blowing agent may be a mixture of a hydrocarbon and a hydrofluoroolefin and / or a chlorinated hydrofluoroolefin.

[0019] The blowing agent may be a mixture of hydrocarbons and halogenated hydrocarbons.

[0020] Preferably, if the blowing agent is a mixture, the blowing agent that is not trapped within the foam is a mixture. Preferably, the method of the present invention recovers (and reuses) the mixture in the same proportions as the blowing agents were mixed for use in the method of the present invention. This means that the blowing agent mixture can be used again without any need for remixing.

[0021] For example, the blowing agent may be an azeotrope of at least two blowing agents. If the blowing agent is an azeotrope, it can be regenerated by condensing (or allowing to condense) it at a given temperature. Azeotropes are generally easier to regenerate in the same ratios in which they were mixed.

[0022] The method of the present invention can be utilized to produce any foam, particularly insulation including polyurethane (PU), polyisocyanurate (PIR), polystyrene (including expanded polystyrene (EPS) and extruded polystyrene (XPS)), and phenolic foams.

[0023] The process of the present invention is particularly suitable when a hydrofluoroolefin is present as the blowing agent.

[0024] For example, the blowing agent may be composed of pentane and especially isopentane and at least one hydrofluoroolefin, such as 1233zd. The blowing agent may be a binary mixture thereof.

[0025] Desirably, the foam reactants are materials that react to form a phenolic foam. For example, the foam reactants can include a phenolic resin. The phenolic resin can have a weight average molecular weight of about 700 to about 2000, and / or the phenolic resin can have a number average molecular weight of about 330 to about 800, such as about 350 to about 700.

[0026] The phenolic resin may have a molar ratio of phenolic groups to aldehyde groups in the range of about 1:1 to about 1:3, preferably about 1:1.5 to about 1:2.3.

[0027] The water content of the foam reactants, which are optionally phenolic foam reactants, may range from about 5 wt % to 12 wt %, such as 6 wt % to 10 wt %, based on the total weight of the foamable composition formed by mixing the foam reactants.

[0028] Desirably, the phenolic resin has a moisture content ranging from about 10 wt % to about 14 wt %.

[0029] Preferably, the phenolic resin has a viscosity of from about 2,500 mPa·s to about 18,000 mPa·s when measured at 25° C., such as from about 2,500 mPa·s to about 16,000 mPa·s when measured at 25° C., such as from about 4,000 mPa·s to about 8,000 mPa·s when measured at 25° C.

[0030] The blowing agent may be used in the process of the present invention in an amount of about 1 to about 20 parts by weight per 100 parts by weight of the resin, e.g., a phenolic resin, which forms part of the foam reactants.

[0031] The blowing agent is typically an organic blowing agent, and the step of recovering the blowing agent not trapped within the foam includes: (i) recovering a mixture of the organic blowing agent and moisture evolved during the production of the foam, and allowing the blowing agent and moisture to condense or cooling (optionally by passing through a heat exchanger) to condense the blowing agent and moisture; (ii) transferring the mixture of organic blowing agent and water into a reservoir, optionally a decanter; (iii) fractionating or allowing the mixture to be fractionated into an aqueous fraction and an organic fraction, optionally by decanting; (iv) recovering the organic fraction. It may consist of the steps.

[0032] The water fraction may be subjected to water polishing and / or air stripping processes, which purifies the recovered water so that it may be reused in the method of the present invention or in other methods altogether.

[0033] The recovered blowing agent can be metered, for example by passing it through a metering pump, before being reused, for example, in the process for producing the foam of the present invention. Metering allows the amount of recycled blowing agent to be calculated so that it can be returned to the process of production according to the present invention in a desired / calculated amount.

[0034] The recovered blowing agent may be subjected to compositional analysis to confirm its composition. For example, if a mixture of blowing agents is used, the compositional ratios of said mixture may be analyzed. Additionally or alternatively, the purity of the blowing agent may be analyzed to determine, for example, whether any residual moisture is present. This may be used to determine whether the blowing agent is suitable for reuse or requires further processing, such as purification, before reuse.

[0035] The recovered blowing agent can be passed through a heat exchanger to achieve and / or maintain a target temperature, typically a constant temperature. Preferably, the recovered blowing agent is passed through a heat exchanger to maintain a temperature below about 25°C, such as below about 20°C, such as below about 17°C. The appropriate temperature can be selected based on the characteristics of the blowing agent used. For example, a heat exchanger can be used to provide / maintain a temperature below the boiling point of the blowing agent used to ensure that the blowing agent remains in a liquid state. As a specific example, if the blowing agent used is E-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd(E)), which has a boiling point of 18.3°C, a heat exchanger can be used to provide / maintain a temperature below 17°C.

[0036] Although it is desirable to recover the blowing agent mixture in the ratio in which it was mixed, this may not be possible. In such cases, the mix ratio can be adjusted before the blowing agent is reused. For example, one blowing agent component can be added in an amount sufficient to restore the blowing agent mixture to the desired ratio. The necessary adjustment can be determined by the results of a compositional analysis of the recovered blowing agent. Suitably, the results of the compositional analysis of the recovered blowing agent are communicated to a metering pump or dispenser that adds one or more components in amounts according to the determined composition. In this way, compensation can be made to ensure that the recycled blowing agent is not specifically different from the blowing agent that was not recycled.

[0037] The foam reactants can be mixed in a heated enclosure. For example, formation of the foam product can occur in a heated oven. The manufacturing system can consist of upper and lower conveyor belts that run through the oven.

[0038] The foam reactants can be mixed on a conveyor system having upper and lower belts. The foam reactants can be discharged onto a conveyor system having upper and lower belts that enter a heated oven, for example at 50 to 100° C., for example, for about 2 to 15 minutes. The foam board thus formed can then be cut to the desired length.

[0039] The method of the present invention may be used to produce a foam comprising at least one facing. Suitably, the method of the present invention may be used to produce a foam comprising a board having an upper surface and a lower surface, at least one surface of the board being provided with a facing. Desirably, the facing is provided on both the top and bottom surfaces of the board.

[0040] One or more of the facings are pre-drilled. Desirably, at least one of the facings can be constructed from a substantially gas impermeable material. The facings can comprise metal foil, such as aluminum foil. The facings can be laminates, such as metal foil laminated onto glass tissue or metal foil laminated onto kraft paper. The facers can be paper, glass tissue, or any other type.

[0041] If at least one facing is used, the foam reactant can be placed on the base facing. Optionally, an upper facing can be placed on top of the foam reactant to form a "sandwich" which can then be guided into a heated oven, for example at 50 to 100° C., for example, about 2 to 15 minutes. The foam board thus formed can then be cut to the desired length.

[0042] Further according to the present invention there is provided a foam, such as a foam insulation board, produced by the method described herein. The foam, which may be a foam insulation board, has the following properties: (a) Approximately 10kg / m 3to about 100 kg / m 3 density; (b) a closed cell content of at least 85% as measured in accordance with standard ASTM D6226; (c) a FIGRA value of 150 W / s or less (preferably 125 W / s or less, 120 W / s or less, or 110 W / s or less, or 100 W / s or less, or 95 W / s or less, or 90 W / s or less, or 85 W / s or less) when measured in accordance with the European Standard EN 13823; 0.2MJ ; (d) a compressive strength in the range of about 95 kPa to about 200 kPa, measured in accordance with European Standard EN826; (e) A FIGRA output of 80 W / s or less when measured in accordance with European Standard EN13823. 0.4MJ ; (f) a thermal conductivity of less than or equal to 0.020 W / m·K, suitably less than or equal to 0.018 W / m·K, preferably less than or equal to 0.0175 W / m·K, or less than or equal to 0.0170 W / m·K, or less than or equal to 0.0165 W / m·K, or less than or equal to 0.0162 W / m·K, when measured at an average temperature of 10°C in accordance with European Standard EN 13166:2012; (g) a limiting oxygen index, measured according to standard ISO 4589-2, of 34% or more, preferably 35% or more, suitably 36% or more, for example 37% or more; (h) a stable moisture content of 3% to 5% by weight when measured in accordance with European Standard EN 1249:1998 at a temperature of (23 ± 2) °C and a relative humidity of (50 ± 5)%; The present invention may have one or more of the following:

[0043] Further in accordance with the present invention there is provided an apparatus for producing a foam comprising a dispenser for dispensing foam reactants, a dispenser for dispensing a blowing agent, a reactor (such as an oven having a conveyor belt) in which the foam reactants may react to form a foam having gas cells defined therein and the blowing agent trapped within the gas cells, and a collector for recovering the blowing agent not trapped within the foam, optionally as part of a mixture.

[0044] It will be appreciated that any of the methods of the present invention may be carried out using such an apparatus.

[0045] The apparatus of the present invention may further include a reuse system for reusing any of the blowing agent not trapped within the foam, which may take the form of a continuous production apparatus for continually reusing any of the blowing agent not trapped within the foam.

[0046] The apparatus according to the invention may further comprise at least one condenser or heat exchanger for cooling the blowing agent that is not trapped within the foam and is recovered. If the blowing agent is recovered as a gas, the apparatus may comprise a condenser for condensing the blowing agent and / or a heat exchanger for maintaining the blowing agent below its boiling point.

[0047] The apparatus according to the invention may further comprise a reservoir for recovered blowing agent (and optionally any other components from which the blowing agent is recovered). Suitably, the apparatus comprises a decanter. If the blowing agent is recovered as part of a mixture, the apparatus desirably comprises a decanter which can be used to fractionate the mixture into an organic fraction and an aqueous fraction. Additionally or alternatively, the apparatus may comprise another means for separating the blowing agent from the mixture, for example a distillation apparatus. It will be appreciated that this may be done as well if the blowing agent is a mixture and it is desired to separate the components of the mixture from each other.

[0048] The apparatus according to the invention may further comprise at least one analytical instrument for analysing the composition of said recovered blowing agent, optionally as part of a mixture. Preferably, said at least one analytical instrument comprises a sampler, such as an autosampler, for taking a sample of said recovered blowing agent to be analysed.

[0049] The device according to the invention may further comprise at least one pump. Preferably, it comprises at least one metering pump. Desirably, it comprises at least one metering pump in communication with an analytical instrument for analyzing the composition of the recovered blowing agent. [Brief description of the drawings]

[0050] [Figure 1] FIG. 1 is a simplified diagram illustrating a method for producing a foam, such as a foam insulation board, comprising the steps of: (i) providing foam reactants that react to form a foam; (ii) providing a blowing agent; (iii) expanding the foam reactants with the blowing agent to form a foam having gas cells defined therein during reaction of the foam reactants and having the blowing agent trapped within the gas cells; and (iv) recovering the blowing agent that is not trapped within the foam. [Diagram 2] FIG. 2 is a flow diagram illustrating how the method of the present invention can be used to reclaim residual blowing agent from a foam manufacturing process. [Diagram 3] FIG. 3 is a simplified diagram illustrating steps that can be taken for the blowing agent that is not trapped within the blowing agent to be reused in a second foam production step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0052] The expression "at least one X selected from the group consisting of A, B, C and combinations thereof" is defined such that X includes "at least one A" or "at least one B" or "at least one C" or "at least one A in combination with at least one B" or "at least one A in combination with at least one C" or "at least one B in combination with at least one C" or "at least one A in combination with at least one B and at least one C".

[0053] The term "blowing agent" is defined as a propellant used to blow a foamable composition to form a foam. For example, a blowing agent can be used to blow / expand a resin to form a foam.

[0054] A simplified representation of the method according to the present invention is shown in Figure 1. The process comprises providing 100 a foam reactant, providing 102 a blowing agent, and expanding 104 the foam reactant with the blowing agent during reaction of the foam reactant. This reaction and expansion process 104 forms a foam 106 having gas cells defined therein and the blowing agent trapped within the gas cells, and recovering 108 the blowing agent not trapped within the foam.

[0055] Figure 2 shows how the blowing agent regenerated by the method of the present invention can be reused. The foam reactants and blowing agent are subjected to a foam production process 200 during which the blowing agent not trapped within the foam is recovered as part of a gas mixture 202. The gas mixture is cooled 204 to condense the blowing agent and any water vapor recovered therewith. The blowing agent and moisture are then separated 206. The composition of the recovered blowing agent is analyzed 208 and the recovered blowing agent is then reused 210 in further foam production processes.

[0056] An example of a process that may be performed on the recovered blowing agent for reuse in a second foam production process is shown in FIG. 3. The foam reactants and blowing agent are subjected to a foam production process 300. The blowing agent that is not trapped within the foam is removed as part of a gas mixture 302 in a vessel 304. The gas mixture is passed through a condenser 306 to condense the blowing agent and any trapped water vapor, and then sent to a decanter 308. In the decanter 308, the mixture is fractionated into an aqueous fraction 310, which constitutes the blowing agent, and an organic fraction 312. Optionally, the aqueous fraction 310 is removed and subjected to a water polishing or air stripping process. The organic fraction 312 is passed through a pump 316, which pumps it through a heat exchanger 318 and into a vessel 320. The organic components that make up the blowing agent then undergo compositional analysis 322 to determine its composition before being introduced via metering pump 324 to further the foam production process 326 .

[0057] Blowing agent that is not trapped within the foam can be collected in a number of suitable ways depending on the foam production process. For example, an extraction hood can be placed in / on the equipment in which the foam is made. Such an extraction hood can use an exhaust fan to draw the gas mixture of air and volatile organic solvents, including the blowing agent, from the vicinity of the foam production process, optionally into a collection vessel.

[0058] The blowing agent can be collected in a gas mixture, which can then be cooled to condense the blowing agent, for example, the gas mixture can be passed through a condenser and the condensate can then be collected as a liquid.

[0059] The blowing agent may be recovered as a mixture with water vapor. Again, such a mixture may be cooled, for example by passing through a condenser, to condense the blowing agent. This may be done at a temperature at which the blowing agent condenses and may be recovered as a liquid, but the water vapor remains in a gaseous state. Alternatively, the mixture may be cooled to a temperature at which both the blowing agent and water vapor condense and may be recovered as a liquid.

[0060] If the blowing agent is recovered in a gas mixture, it can then be separated from the mixture. As an example, if the blowing agent is recovered as part of a mixture with water vapor, the mixture can be fed into a decanter which will separate it into an aqueous and an organic fraction. The mixture can be fed to the decanter as a liquid after passing through a condenser. Alternatively, the mixture can be fed to the decanter as a gas and then cooled in situ to condense the mixture, at which stage it can be separated into an organic and an aqueous fraction.

[0061] Most common blowing agents are immiscible with water, and therefore the recovered blowing agent-water mixture will naturally separate into an organic fraction and an aqueous fraction, for example after being fed into a decanter. Both fractions can then be easily removed separately, for example through a plug at the bottom of the decanter (if the organic fraction is more concentrated than the aqueous fraction) or through a pump. However, if the blowing agent is miscible with water, it can be separated from the mixture using other methods known in the art, for example by distillation.

[0062] The organic fraction of the blowing agent recovered can be removed from the mixture and passed through a heat exchanger. For example, a pump can be installed to pump the organic fraction from the decanter through a heat exchanger into a further vessel. The heat exchanger can be used to keep the organic fraction of the blowing agent recovered at a constant temperature. The appropriate temperature can be selected based on the characteristics of the blowing agent used. For example, the heat exchanger can be used to maintain a temperature below the boiling point of the blowing agent used, so that the blowing agent remains in a liquid state. As a specific example, if the blowing agent is E-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd(E)) and has a boiling point of 18.3°C, a heat exchanger can be used to maintain a temperature below 17°C.

[0063] The organic fraction of recovered blowing agent may be subjected to some type of compositional analysis prior to reuse in further foam manufacturing processes, which may include measurement or determination of the components present and their densities, concentrations, or any other properties that may be measured by analytical means known in the art.

[0064] Compositional analysis can be performed on the organic fraction of recovered blowing agent while it is in the liquid phase, for example after passing through a condenser or through a heat exchanger that maintains the temperature below its boiling point. Alternatively, compositional analysis can be performed on the organic fraction of recovered blowing agent while it is in the gas phase.

[0065] The compositional analysis of the recovered blowing agent organic fraction can be carried out using any analytical method or instrument known to those skilled in the art. For example, the compositional analysis can be carried out using IR spectroscopy, NIR spectroscopy, or Raman spectroscopy. Alternatively, density and / or mass flow meters can be used.

[0066] Compositional analysis of the organic fraction of recovered blowing agent can be performed using analytical equipment in an in-line or online process that allows for continuous analysis of the stream without the need for separate sampling. Alternatively, samples of the fraction can be taken, either manually or by an automated process, and the analysis performed offline.

[0067] The recovered organic fraction of the blowing agent can be reused as a blowing agent in the production of foams. The recovered crude organic fraction of the blowing agent can be reused as a blowing agent in the production of foams, whether or not it has first been subjected to compositional analysis. Alternatively, the recovered organic fraction of the blowing agent can be mixed with at least one other component prior to use as a blowing agent in the production of foams.

[0068] If the composition of the organic fraction of recovered blowing agent is known, e.g., has been subjected to a compositional analysis, it can be mixed with at least one other component in an amount or ratio determined by the composition. This can be done automatically, e.g., the device used for the compositional analysis can be in communication with yet another device, e.g., a metering pump, which can be used to add the further component or components in an amount determined based on the output of the compositional analysis.

[0069] The at least one other component can be added to a vessel already containing the organic fraction of the recovered blowing agent. Alternatively, the organic fraction of the recovered blowing agent can be added to a vessel already containing the at least one other component. Alternatively, the at least one other component and the organic fraction of the recovered blowing agent can be introduced into a vessel simultaneously.

[0070] The at least one other ingredient and the organic fraction of the recovered blowing agent can be mixed or combined prior to being introduced into the foam production process, or alternatively, the at least one other ingredient and the organic fraction of the recovered blowing agent can be added directly and simultaneously to the foam production process.

[0071] The method of the present invention can be applied to the production of any foam. For example, the method is suitable for the production of polyisocyanurate foams, polyurethane foams, and phenolic foams, among others. The type of foam produced by the method of the present invention can be determined by the selection of foam reactants.

[0072] When the method is used to produce a phenolic foam, the foam reactant used may be a foamable phenolic composition.

[0073] Similarly, the recovered blowing agent can be reused in the production of any foam, for example, the recovered blowing agent may be suitable for the production of polyisocyanurate foams, polyurethane foams, and phenolic foams, among others.

[0074] The apparatus of the present invention can be used to produce any foam, such as polyisocyanurate foams, polyurethane foams, and phenolic foams, among others.

[0075] As used herein in relation to the present invention, the terms "comprises / comprising" and "having / including" are used to specify the presence of stated features, integers, steps or components, but do not exclude the presence or addition of one or more other features, integers, steps, components or sets thereof.

[0076] It is understood that certain features of the invention which are, for clarity, described in the context of separate embodiments, may also be provided in a single embodiment in combination. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

Claims

1. A method for manufacturing a foam such as a foam insulation board, comprising: (i) providing a foam reactant for reacting to form the foam; (ii) providing a blowing agent; (iii) during the reaction of the foam reactant, using the blowing agent to expand the foam reactant to form a foam in which air bubbles are defined and the blowing agent is trapped in the air bubbles; and (iv) recovering the blowing agent not trapped in the foam.

2. The method according to claim 1, wherein the step of recovering the blowing agent comprises recovering the blowing agent as a gas.

3. The method according to claim 1, wherein the step of recovering the blowing agent comprises recovering the blowing agent in the gas mixture as a mixture with, for example, water vapor.

4. The method according to claim 3, further comprising separating the blowing agent from the mixture.

5. The method according to claim 1, further comprising reusing the recovered blowing agent in the manufacture of the foam.

6. The method according to claim 1, wherein the recovered blowing agent is continuously reused in the manufacture of the foam by the method according to claim 1.

7. The blowing agent comprises at least one of a hydrocarbon, a halogenated hydrocarbon, a hydrofluoroolefin, a chlorinated hydrofluoroolefin, or a combination thereof, and / or the blowing agent comprises a hydrocarbon such as a C3-C6 hydrocarbon such as butane, such as isobutane, and / or preferably pentane such as isopentane, or a combination thereof. The method according to claim 1.

8. wherein the blowing agent is an unsaturated C ３ -C ６ hydrocarbon, such as butene, or pentene such as isopentene, or a combination thereof, according to the method of claim 1.

9. The method according to claim 1, wherein the blowing agent comprises a hydrofluoroolefin (HFO).

10. The blowing agent comprises a chlorinated hydrofluoroolefin, such as 1-chloro-3,3,3-trifluoropropene (1233zd) or 1-chloro-2,3,3,3-tetrafluoropropene (1224yd) or a combination thereof, and / or the blowing agent comprises a halogenated hydrocarbon such as isopropyl chloride. The method according to claim 1.

11. The method according to claim 1, wherein the blowing agent is a mixture of at least two different blowing agents, preferably an azeotropic mixture of at least two blowing agents.

12. The method according to claim 11, wherein the blowing agent is a mixture of a hydrocarbon and a hydrofluoroolefin and / or a chlorinated hydrofluoroolefin, or the blowing agent is a mixture of a hydrocarbon and a halogenated hydrocarbon.

13. The foam reactant is a substance that undergoes a reaction to form a phenolic foam, and optionally, the foam reactant contains a phenolic resin, and the phenolic resin has the following properties: a. A weight average molecular weight of from about 700 to about 2000; b. A number average molecular weight of from about 330 to about 800, such as from about 350 to about 700; c. A molar ratio of phenolic groups to aldehyde groups in the range of from about 1:1 to about 1:3, such as from about 1:1.5 to about 1:2.3; d. A water content in the range of from about 10 wt% to about 14 wt%; e. A viscosity of from about 2,500 mPa·s to about 18,000 mPa·s when measured at 25°C, such as from about 2,500 mPa·s to about 16,000 mPa·s when measured at 25°C, or such as from about 4,000 mPa·s to about 8,000 mPa·s when measured at 25°C. The method according to claim 1, having any one or more of the above.

14. The water content of the foam reactant, which is optionally a phenolic foam reactant, is in the range of from about 5 wt% to about 12 wt%, such as from 6 wt% to 10 wt%, based on the total weight of the foamable composition formed by mixing the foam reactants. The method according to claim 1.

15. The method according to claim 1, wherein the blowing agent is present in an amount of from about 1 to about 20 parts by weight per 100 parts by weight of the resin, such as a phenolic resin, which forms part of the foam reactant.

16. The blowing agent is an organic blowing agent, and the step of recovering the blowing agent not trapped in the foam comprises: (i) recovering a mixture of the organic blowing agent and water released during the production of the foam, and cooling and condensing the blowing agent and water by making them condensable or optionally passing them through a heat exchanger; (ii) transferring the mixture of the organic blowing agent and water into a reservoir, which is optionally a decanter; (iii) fractionating or making fractionable the mixture into a water fraction and an organic fraction by optionally decanting. (iv) Optionally, cooling the organic fraction by passing it, optionally, through a heat exchanger to a temperature below about 25 °C, for example below about 20 °C, for example below about 17 °C, (v) Recovering the organic fraction, The method according to claim 1, comprising the steps.

17. The method according to claim 1, wherein the recovered blowing agent is metered, for example by passing it through a metering pump, before being reused, for example, within the method for producing the foam described in claim 1.

18. The method according to claim 1, wherein the reactants are mixed in a heated enclosure and / or the reactants are mixed on a conveyor system having upper and lower belts.

19. An apparatus for producing a foam, comprising: (i) A dispenser for dispensing a foam reactant; (ii) A dispenser for dispensing a blowing agent; (iii) An instrument in which the foam reactant can react to form a foam in which bubbles are defined and the blowing agent is trapped within the bubbles; (iv) A recovery device for recovering the blowing agent not trapped in the foam, optionally as a portion of the mixture; (v) Optionally, a reuse system for reusing the recovered blowing agent not trapped in the foam; The apparatus consisting of.

20. A reuse system for reusing the recovered blowing agent not trapped in the foam, comprising a continuous production apparatus for continuously reusing the recovered blowing agent not trapped in the foam, and optionally further comprising: a. A condenser or heat exchanger for cooling the recovered blowing agent, optionally as a portion of the mixture; b. A reservoir, optionally a decanter, for fractionating the mixture consisting of the recovered blowing agent into an aqueous fraction and an organic fraction; c. At least one analytical instrument for analyzing the composition of the recovered blowing agent, optionally as a portion of the mixture; The apparatus according to claim 19, comprising at least one of the above.

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