Field

[0001] The present invention relates to an insulation product of the type used for thermal insulation. It also relates to a method of manufacturing an insulation product and also any temperature controlled enclosure such as: a building, a cold store, a refrigerator, a vehicle having a temperature controlled area, a container, for example a refrigerated container, comprising the insulation product.

Background

[0002] It is known to provide many types of insulation products. These include foam boards, which may have different facers, vacuum insulation panels (VIPs) which can be encapsulated in a foam, and materials that form an insulating body such as injectable foams, flowable forms including particulate matter than be blown into wall cavities etc. [0003] For the most part such insulation products see a degradation in insulation performance over time. For example, foams may lose blowing agent from closed cells as it gradually replaced with air. Accordingly, the thermal conductivity (lambda value) increases overtime representing a decrease in the insulation performance of the product (aged lambda value). [0004] In an ideal situation, there would be no loss of insulation performance of time.

[0005] In the case of foams, polyurethane (PUR) foams; polyisocyanurate (PIR) foams polystyrene foams (XPS and EPS) and phenolic foams are all well-known and used in various end-use applications.

[0006] Often times foam products are provided with one or more facers. For example, it is common to provide facers on opposing sides of a foam board. Gas permeable or gas impermeable facers may be utilised. Furthermore, it is also known to provide facers which are gas permeable which are formed from a gas impermeable material that has been perforated to create pores. For those products where the facer forms a gas tight barrier, loss of blowing agent may be reduced due to the presence of the facer. However, in most cases the facer is chosen based on the end use application. For example, metallic foil facers may be chosen to improve emissivity values. Other facers may be chosen for their appearance, while other facers may be chosen for the function they will fulfil when in use. It will be noted that phenolic foams cannot be provided with gas tight facers due to the fact that the reaction which forms the phenolic foam releases water and the water needs to be removed during curing/drying. Accordingly, for phenolic foams gas permeable facers and/or perforated facers of the type described above, such as perforated metallic facers (e.g. laminate facers comprising an aluminium layer) have been utilised. [0007] Generally speaking, phenolic foams tend to have the best insulation performance over time. In other words, the thermal conductivity tends to be the most stable (stable lambda). Even though phenolic foams tend to have the best insulation performance over time, the thermal conductivity of all foams, including phenolic foams, does tend to disimprove somewhat due to the ingress of air (replacing blowing agent) as described above.

[0008] Accordingly, the thermal conductivity (lambda value) of all foams tends to move upwards over time. This is often referred to as“lambda drift”. In simplistic terms it is very desirable to have“stable lambda” over a long period of time representing a stable thermal conductivity rather than having“lambda drift” where the thermal conductivity increases over time.

[0009] Lambda drift is the generally the product of two concurrent diffusion processes. Air diffusion into the closed cells through the polymer matrix, and diffusion of blowing agent out of the closed cells. Of the two diffusion processes, the diffusion of air into the closed cells occurs more quickly, than the diffusion of blowing agent from the closed cells. The rate of diffusion of blowing agent from the closed-cells will depend on the nature of the blowing agent and the polymer matrix.

[0010] It is generally accepted that the thermal conductivity of foams is dependent on the type of cells formed in the foam, and the nature of the blowing agent retained therein. Blowing agent retention is higher in closed cells. The matrix forming the walls of closed cells, forms a barrier to air ingress into the cell and also to blowing agent egress from the cell. Accordingly, a foam with more closed cells will exhibit a better thermal performance over time. For example, for a given foam material (with the same blowing agent), a foam having a closed cell content of 90% or higher will have both a better initial and aged thermal performance than the same foam (and same blowing agent) where the closed cell content is for example 70%.

[0011] A VIP on the other hand generally comprises a single panel of insulation material, an insulation core, formed typically of fumed silica, mineral fibre or other microporous material, which may or may not contain infra-red opacifiers, the core wrapped in a flexible gas-tight envelope to which a vacuum is applied before sealing. VIPs may also be formed from insulation cores formed from porous/open cell foams. Having a porous/open cell core allows the air that is present in the core to be removed upon application of a vacuum. In general, the more porous/open cells that are present, the easier it is to remove air from the core. As a general rule the more air that is removed the better the thermal conductivity value from an insulation point of view because of course the closer the VIP can be to a perfect vacuum the better its insulation properties. And of course the easier it is to remove that air, the less energy is required to achieve a desired stable vacuum pressure within the envelope of the VIP. [0012] VIPs too may gradually lose vacuum, due to ingress of air. And of course, with a loss of vacuum comes loss of thermal insulation properties. Furthermore, if the envelope of a VIP is compromised, for example if the envelope is punctured, the thermal conductivity value increases substantially immediately as air enters the envelope and finds its way into the core. [0013] Accordingly, it remains desirable to provide insulation products which exhibit good initial thermal insulation properties and which maintain that performance over time. Furthermore, it remains desirable that such insulation products have good fire performance characteristics.

Summary of the Invention

[0014] In one aspect, the present invention provides an insulation product comprising: (i) a foam insulation core, said foam insulation core having a plurality of closed cells and a plurality of open cells, said closed cells comprising a blowing agent, said foam insulation core having a closed cell content of at least 70% as determined in accordance with ASTM D6226; and

(ii) an envelope defining an enclosed space, and arranged to envelop the foam insulation core, and to maintain an applied vacuum within the envelope; wherein an atmosphere held within one or more open cells of the foam insulation core and/or within one or more voids of the foam insulation core has a reduced pressure relative to atmospheric pressure, said atmosphere held within said one or more open cells and/or said one or more voids of the foam insulation core being maintained in the range of from 150 mbar to 800 mbar by the envelope. [0015] Suitably, the atmosphere held within open cells of the foam insulation core may be maintained in the range of from 150 mbar to 700 mbar by the envelope, such as from 200 mbar to 650 mbar. Preferably, the atmosphere held within open cells of the foam insulation core may be maintained in the range of from 200 mbar to 500 mbar by the envelope, for example from 200 mbar to 300 mbar, suitably the atmosphere held within open cells of the foam insulation core may be maintained in the range of from 220 mbar to 280 mbar. Advantageously, the atmosphere held within the open cells of the foam which is maintained by the envelope, is significantly higher in pressure than the internal atmosphere in a VIP. Thus the panels of the present invention may be considered “partially” evacuated. By maintaining the internal gas pressure which is held by the envelope in the open cells of the foam in the range of from 150 mbar to 800 mbar, preferably from 200 mbar to 500 mbar, the concentration of air/moisture surrounding the closed cells of the foam is very low, therefore air/moisture ingress from open cells into the closed cells of the foam over time is significantly reduced, in comparison to a corresponding foam panel which has not been enveloped and“partially” evacuated. [0016] The foam insulation core may comprise a thermoset foam. For example, the foam insulation core may comprise a phenolic foam, a polyisocyanurate foam or a polyurethane foam.

[0017] The foam insulation core may comprise a thermoplastic foam. For example, the foam insulation core may comprise a polyolefin foam, wherein the polyolefin may be formed from monovinyl aromatic compounds of the formula Ar-CHCH2 wherein Ar is an aromatic hydrocarbon radical of benzene type compounds. For example, the thermoplastic foam may be a polystyrene foam. Other examples of suitable thermoplastic foams include foams formed from polyolefins such as polyethylene, ethylene copolymers, polypropylene and polyethyleneterephthalate. The thermoplastic foam may be an extruded foam.

[0018] The envelope may comprise a metallised film. Suitably, the envelope comprises a metallised polymer film, such as a metallised polyester film. The metallised polyester film, may for example comprise a metallised polyethyleneterephthalate (PET) film. The envelope may comprise one or more metallised films. The envelope may comprise an aluminium foil combined with a metallised film. The envelope may comprise an outer protective layer, for example an outer protective layer formed from polypropylene or nylon for enhanced mechanical durability. [0019] The envelope may have a moisture vapour transmission rate (MVTR) of 0.1 g/m ² .day or less, when measured in accordance with ASTM F1249-90, preferably the MVTR is 0.01 g/m ² .day or less, more preferably the MVTR is 0.005 g/m ² .day or less. For example, the envelope may have an MVTR of from about 0.1 g/m ² .day to about 0.001 g/m ² .day, suitably from 0.05 g/m ² .day to 0.005 g/m ² .day, such as from 0.03 g/m ² .day to 0.007 g/m ² .day when measured in accordance with ASTM F1249-90 (measured at 38°C with 100% relative humidity).

[0020] Advantageously, the envelope forms a barrier to moisture ingress, into the insulation product, thereby reducing moisture ingress into the closed cells of the foam insulation core. This in turn enhances the aged thermal performance of the insulation product.

[0021] The envelope may have an oxygen transmission rate (OTR) of 0.005 cc/m ² .day or less when measured in accordance with ASTM D3985, preferably the OTR is 0.0005 cc/m ² .day or less, more preferably the OTR is 0.0001 or less. For example, the envelope may have an OTR of from 0.005 cc/m ² .day to 0.0001 cc/m ² .day, suitably the OTR may be 0.001 cc/m ² .day to 0.0001 cc/m ² .day, such as from 0.0005 cc/m ² .day to 0.0001 cc/m ² .day when measured in accordance with ASTM D3985 (measured at 23°C with 50% relative humidity).

[0022] Advantageously, the envelope forms a barrier to air ingress, into the insulation product, thereby reducing air ingress into the closed cells of the foam insulation core. This in turn enhances the aged thermal performance of the insulation product.

[0023] Advantageously, the insulation products according to the invention may have an aged thermal conductivity of 0.025 W/m.K or less. For example, the insulation products according to the invention may have an aged thermal conductivity of 0.022 W/m.K or less, such as 0.020 W/m.K or less, or 0.18 W/m.K or less or 0.016 W/m.K or less. Suitably, the insulation products according to the invention may have an aged thermal conductivity of from 0.014 to 0.022 W/m.K. [0024] The foam insulation core may comprise a gas permeable facer on at least one major surface thereof, e.g. on an upper surface, or on a lower surface thereof. The foam insulation core may comprise a gas permeable facer on both major surfaces i.e. on the upper surface and on the lower surface. The facer may for example be formed of glass fibre, glass wool, kraft paper, organic fibre mats and/or laminates thereof. Alternatively, the facer may be a formed from a perforated gas impermeable material, for example, the facer may be a perforated aluminium foil, or a perforated aluminium composite material, such as a perforated laminate facer comprising one or more aluminium layers and one or more polymer layers, for example the facer may comprise a perforated metalised polyethylene terephthalate film. [0025] Suitably, the foam insulation product may comprise a getter. For example the getter may comprise calcium oxide or zeolite. Suitably the getter is a mixture of calcium oxide and zeolite.

[0026] In another aspect, the present invention provides a process for manufacturing an insulation product as described herein comprising the following steps: (i) providing a foam insulation core, said foam insulation core having a plurality of closed cells and a plurality of open cells, said closed cells comprising a blowing agent, said foam insulation core having a closed cell content of at least 70% as determined in accordance with ASTM D6226;

(ii) enveloping said foam insulation core in a gas tight envelope; (iii) applying a reduced pressure to evacuate the envelope and

(iv) hermetically sealing the envelope.

[0027] Suitably, a reduced pressure of 150 to 450 mBar is applied to evacuate the envelope for a period of from 30 to 600 seconds. For example, the vacuum may be applied for a period of from 60 to 300 seconds, preferably, the vacuum may be applied for a period of from 60 to 180 seconds. [0028] Advantageously, the insulation product as disclosed herein has superior aged thermal performance in comparison to a foam panel which has not been enveloped and exposed to vacuum as provided in the method of the present invention.

[0029] Advantageously, the insulation product as disclosed herein may be used in applications where the product may be exposed to moisture. For example, the insulation product may be used in an inverted roof structure. The insulation product may be used in areas where exposure to moisture may occur without a significant impact on the lifetime or a thermal insulating performance of the insulation product.

[0030] Furthermore, the insulation product of the present invention may be used as an alternative to VIPs. As outlined above, if the envelope of a VIP is compromised e.g. punctured, the thermal conductivity value increases substantially immediately as air enters the envelope. However, in an analogous situation whereby the envelope of the insulation product of the present invention is punctured, the insulation performance of the product is less deleteriously impacted since the foam insulation core comprises a blowing agent having a low thermal conductivity.

[0031] A further advantage of the present insulation product is that relative to other insulation products, the presence of the gas tight envelope ensures practically no blowing agent is released from the product into the atmosphere.

Brief Description of the Drawings

[0032] Embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings in which:

[0033] Figure 1 is a cut-away perspective view of an insulation product according to the present invention. [0034] Figure 2 is a schematic of the envelope lift off procedure for determining the pressure in the open cells of the foam insulation product which is held by the envelope.

Definitions [0035] The phrase“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”.

[0036] The phrase Ύ may be selected from A, B, C and combinations thereof” implies Y may be A, or B, or C, or A+B, or A+C, or B+C, or A+B+C.

[0037] The term“blowing agent” is defined as the propelling agent employed to blow the foamable composition for forming a foam. For example, a blowing agent may be employed to blow a resin to form a foam.

Description

[0038] As outlined above, the present invention provides an insulation product comprising: (i) a foam insulation core, said foam insulation core having a plurality of closed cells and a plurality of open cells, said closed cells comprising a blowing agent, said foam insulation core having a closed cell content of at least 70% as determined in accordance with ASTM D6226; and (ii) an envelope defining an enclosed space, and arranged to envelop the foam insulation core, and to maintain an applied vacuum within the envelope; wherein an atmosphere held within one or more open cells of the foam insulation core and/or within one or more voids of the foam insulation core has a reduced pressure relative to atmospheric pressure, said atmosphere held within said one or more open cells and/or said one or more voids of the foam insulation core being maintained in the range of from 150 mbar to 800 mbar by the envelope.

[0039] The atmosphere held within all of the open cells of the foam insulation core may have a reduced pressure relative to atmospheric pressure.

[0040] The atmosphere held within all of the voids of the foam may have a reduced pressure relative to atmospheric pressure.

[0041] The atmosphere held within the one or more or all of the open cells of the foam insulation core may have a reduced pressure relative to the pressure within the closed cells of the foam. [0042] The atmosphere held within the one or more or all of the voids of the foam insulation core may have a reduced pressure relative to the pressure within the closed cells of the foam.

[0043] The foam insulation product may comprise a getter. For example the getter may comprise calcium oxide or zeolite. Suitably the getter is a mixture of calcium oxide and zeolite. Other suitable getters will be known to the person skilled in the art, for example those described in European Patent Application Publication No. EP2752397 to Lee.

[0044] The insulation product may be an insulation panel, for example, the insulation panel may be parallelepiped in shape. [0045] The foam insulation core may be a thermoset foam or a thermoplastic foam. Preferably, the foam insulation core is a thermoset foam, for example, the foam insulation core may be a phenolic foam, a polyurethane foam or a polyisocyanurate foam. More preferably, the foam insulation core is a phenolic foam. The person skilled in the art is familiar with methods for forming such foam insulation cores. [0046] Optionally, the foam insulation core is substantially parallelepiped in shape. For example, the foam insulation core may be cuboid. Preferably, the foam insulation core comprises an upper surface a lower surface and sides. However, the person skilled in the art will appreciate that the foam insulation core may be alternative shapes, for example, the foam insulation core may be in the shape of a pipe section, such as substantially C-shaped or U-shaped.

[0047] A phenolic foam insulation core may be formed by foaming and curing a phenolic resin composition that comprises, for example, a phenolic resin, a surfactant, a blowing agent and a curing catalyst. Any of the methods well known in the art, such as those described in US Patent Publication No. 4444912 to Carlson, or those described in International Patent Application Publication No. W02007029221 to Coppock, each of which is incorporated herein by reference, may be employed to form a foam insulation core for use in the present invention.

[0048] A preferred type of phenolic resin which may be employed in the manufacture of a phenolic foam for use as a foam insulation core in the present invention is a resole resin. Such resole resin can be obtained from the chemical reaction of phenol or a phenol based compound such as cresol, xylenol, para-alkylphenol, para- phenylphenol, resorcinol, and the like with an aldehyde such as formaldehyde, furfural, acetaldehyde and the like using a catalytic amount of alkali such as sodium hydroxide, potassium hydroxide, calcium hydroxide, or an aliphatic amine such as trimethylamine, or triethylamine. These types of chemical constituent are commonly used in standard resole resin production, but the invention is not limited to phenolic foams manufactured from phenol resins formed from only those chemicals listed here.

[0049] The molar ratio of phenol groups to aldehyde groups is in the range from 1 :1 to 1 :3, suitably from 1 :1.5 to 1 :2.5, and more suitably from 1 :1.6 to 1 :2.3. As the molar ratio of phenol to aldehyde groups decreases foams have increased residual formaldehyde. [0050] A preferred weight average molecular weight suitable for the phenolic resin is from 700 to 2,000, such as from 700 to 1600.

[0051] The number average molecular weight is suitably from 330 to 1 ,000, and preferably from 350 to 800, such as from 350 to 700.

[0052] Suitably, the weight average molecular weight may be from 700 to 1600, and the number average molecular weight is at least 350.

[0053] The water content of the phenolic resin may be from about 3 wt% to about 20 wt%, such as from about 5 wt% to about 18 wt%, suitably from about 6 wt% to about 16 wt%, more suitably, from about 1 1 wt% to about 15 wt% based on the total weight of the phenolic resin, and as determined by Karl Fisher analysis. [0054] The phenolic resin preferably has a free formaldehyde content of less than

3 wt% based on the total weight of the phenolic resin composition, such as a free formaldehyde content of less than 2 wt% based on the total weight of the phenolic resin. The phenolic resin may comprise a free formaldehyde content of from about 0.5 wt% to about 2 wt% based on the total weight of the phenolic resin. [0055] The phenolic resin may have a viscosity of 250 mPa-s or more and 50000 mPa-s or less at 40°C. Suitably, the phenolic resin may have a viscosity of 250 mPa-s or more and 30000 mPa-s or less at 40°C. The viscosity of the phenol resin is preferably 1500 mPa-s or more and 30000 mPa-s or less at 40°C. Suitably, the viscosity of the phenol resin is 1500 mPa-s or more and 15000 mPa-s or less at 40°C, such as 1800 mPa-s or more and 12000 mPa-s or less at 40°C. Block phenolic foams may for example be formed using a phenolic resin having a viscosity of 250 mPa-s or more to 10000 mPa-s or less at 40°C. Laminate phenolic foams may for example be formed using a phenolic resin having a viscosity in the range of from 1500 mPa-s or more and 30000 mPa-s or less at 40°C, suitably 1800 mPa-s or more and 12000 mPa-s or less at 40°C.

[0056] The phenolic resin composition comprises a surfactant. As the surfactant, those commonly used for manufacturing phenol resin foams can be used. As the surfactant, among these, nonionic surfactants are effective. For example, alkylene oxides, which are copolymers of ethylene oxide and propylene oxide, condensation products of alkylene oxide and castor oil, condensation products of alkylene oxide and alkylphenol such as nonylphenol and dodecylphenol, polyoxyethylene alkyl ethers of 14- 22 carbon atoms in the alkyl ether moiety, and additionally fatty acid esters such as polyoxyethylene fatty acid esters, silicone compounds such as polydimethylsiloxane, and polyalcohols are preferable. These surfactants may be used singly or two or more of these may be used in combination.

[0057] The amount of surfactant used is not particularly limited, but is suitably used in the range of 0.5 to 8 parts by mass based on 100 parts by mass of the phenol resin. For example, the surfactant may be present in an amount of 1 to 6 parts by weight per 100 parts by weight of phenolic resin. Suitably, the surfactant is present in an amount of from 1.5 to 4.5 parts by weight per 100 parts by weigh of phenolic resin.

[0058] Preferably the surfactant is a castor oil-ethylene oxide adduct wherein more than 5 moles but less than 60 moles of ethylene oxide are added per 1 mole of castor oil. For example the surfactant may be a castor oil-ethylene oxide adduct wherein more than 20 moles but less than 40 moles of ethylene oxide are added per 1 mole of castor oil. Alternative surfactants include but are not limited to alkylene oxide / alkyl phenol condensates (nonyl phenol and dodecyl phenol), silicone compounds such as dimethyl siloxane and commercial surfactants such as DC 193. [0059] The acid catalyst may comprise an aryl sulfonic acid. Suitably, the acid catalyst comprises at least one of benzenesulfonic acid, para-toluene sulfonic acid, xylene sulfonic acid, naphthalene sulfonic acid, ethylbenzene sulfonic acid and phenol sulfonic acid.

[0060] Inorganic acids such as sulfuric acid may also be used. Block phenolic foams for example may be formed using phosphoric acid, sulfuric acid, aryl sulfonic acid may or combinations thereof as the acid catalyst. [0061] Phosphoric acid can be used with organic sulfonic acids, such as with aryl sulfonic acids to regulate reactivity and enhance fire performance.

[0062] Preferably, the acid catalyst may comprise para-toluene sulfonic acid and xylene sulfonic acid. [0063] The acid catalyst may be present in an amount of 5 to 25 parts by weight per 100 parts by weight of phenolic resin. Suitably, the acid catalyst is present in an amount of from about 10 to 20 parts by weight per 100 parts by weight of phenolic resin.

[0064] The blowing agent may comprise any suitable blowing agent. In choosing the blowing agent, it must be remembered that the thermal conductivity of the phenolic foam is directly related to the thermal conductivity of the blowing agent entrapped in the foam i.e. the blowing agent trapped in the closed cells of the foam. Preferably, the blowing agents employed in the manufacture of the foam insulation cores of the present invention have low thermal conductivity and low environmental impact. Preferably, the blowing agents have low global warming potential low ozone depletion potential. Preferably, the blowing agents have good fire retardancy properties. More details of suitable blowing agents for the foam insulation cores employed in the present invention are provided below.

[0065] Optionally, the phenolic resin composition may comprise one or more of each of a plasticiser, an inorganic filler, a flame retardant, a toughener, a formaldehyde scavenger or mixtures thereof.

[0066] Optionally, the phenolic resin composition comprises one or more plasticisers. The plasticiser may be present in an amount of 0.1 to 10 parts by weight per 100 parts by weight of phenolic resin, suitably the plasticiser is present in an amount of from about 2 to 5 parts by weight per 100 parts by weight of phenolic resin. [0067] The plasticiser may be a polyester polyol that is a reaction product of a polybasic carboxylic acid and a polyhydric alcohol. The polybasic carboxylic acid may be at least one acid selected from a dibasic to a tetrabasic carboxylic acid and combinations thereof. The polyhydric alcohol may be selected from a dihydric, trihydric, tetrahydric, a pentahydric alcohol and combinations thereof. The plasticiser could also be a glycol such as ethylene glycol or a polyether polyol.

[0068] The polybasic carboxylic acid used to synthesise the polyester polyol comprises at least one acid selected from the group consisting of: phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2, 3-dicarboxylic acid, naphthalene-1 ,4- dicarboxylic acid, napththalene-2,6-dicarboxylic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, cyclohexane-1 ,2-dicarboxylic acid, cyclohexane-1 ,3- dicarboxylic acid, and cyclohexane-1 ,4-dicarboxylic acid and combinations thereof. Preferably the polybasic carboxylic acid used to synthesise the polyester polyol comprises one or more of phthalic acid, isophthalic acid, and terephthalic acid.

[0069] The polyhydric alcohol used to synthesise the polyester polyol comprises at least one alcohol selected from the group consisting of: ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1 ,4-butane diol, 1 ,5-pentane diol, 1 ,6- hexane diol, neopentyl glycol, 1 ,2-cyclohexane dimethanol, 1 ,3-cyclohexane dimethanol, 1 ,4-cyclohexane dimethanol, and combinations thereof. Preferably the polyhydric alcohol used to synthesise the polyester polyol comprises one or more of diethylene glycol, propylene glycol, dipropylene glycol, 1 ,4-butane diol.

[0070] Optionally, the phenolic foam may comprise one or more inorganic fillers. Suitably, the inorganic filler comprises at least one of a metal oxide such as aluminium oxide or zinc oxide, a metal powder such as zinc powder, or a metal hydroxide such as aluminium hydroxide, magnesium hydroxide, or a metal carbonate such as calcium carbonate, magnesium carbonate, barium carbonate, or zinc carbonate.

[0071] The inorganic filler may be present in an amount of 0.1 to 20 parts by weight per 100 parts by weight of phenolic resin, suitably the inorganic filler is present in an amount of 1 to 10 parts by weight per 100 parts by weight of phenolic resin.

[0072] Suitably, the inorganic filler comprises a metal hydroxide or metal carbonate having an ionic equilibrium solubility (Ksp) less than 10 ⁸ when measured at 25°C. [0073] The metal carbonate may be calcium carbonate or magnesium carbonate.

Suitably, the metal carbonate has an average particle size of 100 - 300 pm, preferably 150 - 200 pm. Suitably the inorganic filler comprises calcium carbonate having an average particle size of from about 120 pm to about 200 pm and an ionic equilibrium solubility (Ksp) of less than 10 ⁸ when measured at 25°C. [0074] The phenolic foam may have a pH of from about 2 to about 8, suitably, of from about 2 to about 6. The phenolic foam may have a pH of 4 or more. [0075] Optionally, the phenolic foam insulation core may comprise a flame retardant. Suitably, the flame retardant may be present in an amount of from about 1 to about 10 parts by weight per hundred parts by weight of the phenolic resin. Optionally, the flame retardant is a liquid organophosphorus compounds, such as but not limited to triethyl phosphate, diphenyl phosphite, diethyl ethyl phosphonate and solid phosphorus based materials such as ammonium polyphosphate, and red phosphorus. Flame retardants such as aluminium trihydrate, zinc borate and halogenated flame retardants can also be used.

[0076] The phenolic foam may comprise a toughening agent. A toughening agent is an organic modifier for co-reacting with the phenolic resin, which toughens i.e. reduces brittleness of the phenolic foam. The toughening agent may be at least one member selected from the group consisting of urea, dicyandiamide and melamine and combinations thereof.

[0077] The toughening agent may be present in an amount of from 1 to 10 parts by weight per 100 parts by weight of the phenolic resin.

[0078] The toughening agent may be urea and be present in about 5 parts by weight per 100 parts by weight of the phenolic resin.

[0079] The blowing agent preferably has low global warming impact and low ozone depletion characteristics and imparts good fire performance properties (i.e. fire retardancy or fire resistance properties) to foams made therewith.

[0080] As outlined above, the foam insulation core of the present invention may be a polyurethane or isocyanurate foam. Such foams may be formed by adding a blowing agent composition to a foamable composition, and reacting the foamable composition under the conditions effective to form a foam or cellular structure that is well known in the art. For example, any of the methods well known in the art for forming polyurethane and polyisocyanurate foams may be employed to form a polyurethane or polyisocyanurate foam insulation core for use in the present invention. For example, the methods described in“Polyurethane Chemistry and Technology,” Volumes I and II, Saunders and Frisch, 1962, John Wiley and Sons, New York, NY, which is incorporated herein by reference, may be used or adapted for use in the manufacture of foam insulation cores of the present invention. In general, such preferred methods comprise preparing polyurethane or polyisocyanurate foams by combining an isocyanate, a polyol or mixture of polyols, a blowing agent, or mixture of blowing agents, and other materials such as catalysts, surfactants and optionally flame retardants, colourants or other additives.

[0081] It is convenient in many applications to provide the components for polyurethane or polyisocyanurate foams in pre-blended formulations. Generally, the foam formulation is pre-blended into two components. The isocyanate and optionally certain additives such as surfactants and blowing agents comprise the first component, commonly referred to as the "A" component. The polyol or polyol mixture, surfactant, catalysts, blowing agents, flame retardant, and other isocyanate reactive components comprise the second component, commonly referred to as the "B" component Accordingly, polyurethane or polyisocyanurate foams are readily prepared by bringing together the A and B side components either by hand mix for small preparations and, preferably, machine mix techniques to form blocks, slabs, laminates, pour-in-place panels and the like. Optionally, other ingredients such as fire retardants, colorants, co- blowing agents, and even other polyols can be added as one or more additional streams to the mix head or reaction site. Most preferably, however, they are all incorporated into one B-component as described above.

[0082] With respect to thermoplastic foams which may be used as the foam insulation core in the insulation product of the present invention, the preferred methods of manufacture generally comprise introducing a blowing agent into a thermoplastic material, preferably a thermoplastic polymer such as polyolefin for example polystyrene, and then subjecting the thermoplastic material to conditions effective to cause foaming. Suitably, the step of introducing the blowing agent into the thermoplastic material may comprise introducing the blowing agent into a screw extruder containing the thermoplastic, and the step of causing foaming may comprise lowering the pressure on the thermoplastic material and thereby causing expansion of the blowing agent and contributing to the foaming of the material.

[0083] It will be appreciated by those skilled in the art, that a thermoplastic insulation foam core for use in the present invention may be formed by any prior art methods for forming thermoplastic insulation foams. For example, a thermoplastic insulation foam core, may be formed from a polyolefin foam, such as a polystyrene foam. Such polyolefin foams may be formed by expanding a blowing agent in a composition suitable for forming a polyolefin foam. For example, a polystyrene foam may be formed by expanding a blowing agent in a composition suitable for forming a polystyrene foam. Suitably, a thermoplastic foam, such as a polystyrene foam, may be formed by extrusion. Any of the methods well known in the art for forming thermoplastic foams may be employed to form a thermoplastic form insulation core for use in the present invention. For example, the methods described in International Patent Application Publication No. W02008118627 to Vo, which is incorporated herein by reference, may be used or adapted for use in the manufacture of foam insulation cores of the present invention.

[0084] The blowing agent used to form the foam insulation core of the present invention may comprise any suitable blowing agent (also called foaming agent). Suitably, the blowing agent comprises at least one member of the group consisting of: a halogenated hydroolefin, a hydrocarbon, a chlorinated hydrocarbon and combinations thereof. The blowing agent may optionally include a co-blowing agent.

[0085] Suitably, the blowing agent comprises a halogenated hydroolefin.

[0086] The halogenated hydroolefin may have the formula:

Wherein each R is independently Cl, F, Br, I or H R’ is (CR2) _n Y,

Y is CRF ₂ , and n is 0, 1 , 2, or 3, preferably 0 or 1.

[0087] Preferably, Y is CF3, n is 0 or 1 and at least one of the remaining R is F. Preferably no Br is present. [0088] The halogenated hydroolefin may for example be at least one olefin, such as a hydrofluoroolefin selected from the group consisting of: hexafluoropropene, 2- fluoropropene, 1-fluoropropene, 1 ,1-difluoropropene, 3,3-difluoropropene, 3,3,3- trifluoropropene, 2,3,3-trifluoropropene, 1 ,3,3,3-tetrafluoropropene, 1 , 1 ,3,3- tetrafluoropropene, 1 ,2,3,3, 3-pentafluoropropene, 4,4,4-trifluoro-1-butene, 3, 4,4,4- tetrafluoro-1 -butene, 1 ,1 ,3,3,3-pentafluoro-2-methyl-1-propene, octafluoro-1 -butene, octafluoro-2-butene, 2,3,3,4,4,4-hexafluoro-1-butene, 1 ,1 ,1 ,4,4,4-hexafluoro-2-butene, 1 ,1 ,1 ,2,4,4,4-heptafluoro-2-butene, 3-fluoropropene, 2,3-difluoropropene, 1 ,1 ,3- trifluoropropene, 1 ,3,3-trifluoropropene, 1 ,1 ,2-trifluoropropene, 1-fluorobutene, 2- fluorobutene, 2-fluoro-2-butene, 1 , 1 -difluoro-1 -butene, 3, 3-difluoro-1 -butene, 3,4,4- trifluoro-1 -butene, 2,3,3-trifluoro-1-butene, 1 ,1 , 3, 3-tetrafluoro-1 -butene, 1 , 4,4,4- tetrafluoro-1 -butene, 3,3,4,4-tetrafluoro-1-butene, 4, 4-difluoro-1 -butene, 1 ,1 ,1 -trifluoro- 2-butene, 2,4,4,4-tetrafluoro-1-butene, 1 ,1 ,1 ,2-tetrafluoro-2-butene, 1 ,1 ,4,4,4- pentafluoro-1 -butene, 2,3,3,4,4-pentafluoro-1 -butene, 1 ,2,3,3,4,4,4-heptafluoro-1 - butene, 1 ,1 ,2,3, 4,4,4-heptafluoro-1 -butene, and 1 ,3,3,3-tetrafluoro-2-(trifluoromethyl)- propene and combinations thereof.

[0089] Additionally or alternatively, the halogenated hydroolefin may be at least one olefin selected from the group consisting of 1-chloro-3,3,3-trifluoropropene and 2- chloro-3,3,3-trifluoropropene and combinations thereof.

[0090] Suitably, the halogenated hydroolefin is at least one olefin selected from the group consisting of 1-chloro-3,3,3-trifluoropropene, 1 ,3,3,3-tetrafluoropropene, 2,3,3,3-tetrafluoropropene, 1 ,1 ,1 ,4,4,4-hexafluoro-2-butene, and combinations thereof. [0091] Advantageously, foams produced using halogenated hydroolefins as blowing agents demonstrate excellent thermal performance and have low global warming impact and low ozone depletion.

[0092] The blowing agent may comprise a hydrocarbon, for example, the blowing agent may comprise an aliphatic hydrocarbon containing from 3 to 7 carbon atoms. Suitably, the blowing agent may comprise a least one aliphatic hydrocarbon containing 3 to 7 carbon atoms selected from the group consisting of propane, butane, pentane, hexane, heptane, isomers thereof and combinations thereof. The blowing agent may comprise mixtures of hydrocarbons.

[0093] Suitably, the blowing agent may comprise at least one compound selected from the group consisting of propane, butane, isobutane, pentane, isopentane, cyclopentane, hexane, cyclohexane, isohexane, neohexane, heptane, isoheptane, cycloheptane and combinations thereof.

[0094] The blowing agent may comprise a blend of a halogenated hydroolefin and an aliphatic hydrocarbon containing from 3 to 7 carbon atoms. [0095] Optionally, said blowing agent may comprise the halogenated hydroolefin in at least 60 wt% based on the total weight of the blowing agent, preferably at least 70 wt% based on the total weight of the blowing agent, more preferably at least 80 wt% based on the total weight of the blowing agent, even more preferably at least 85 wt% based on the total weight of the blowing agent.

[0096] Suitably, the aliphatic hydrocarbon containing from 3 to 7 carbon atoms in the aforesaid blend will be present in an amount of from 1 to 40 wt% based on the total weight of the blowing agent. Preferably, in an amount of at least 5 wt% based on the total weight of the blowing agent. More preferably in an amount of at least 10 wt% based on the total weight of the blowing agent, even more preferably in an amount of at least 15 wt% based on the total weight of the blowing agent, such as in an amount of at least 20 wt% based on the total weight of the blowing agent. [0097] Suitably, the blowing agent may comprise a blend of 1-chloro-3,3,3- trifluoropropene and one or more of propane, butane, pentane, hexane, heptane and isomers thereof.

[0098] For example the blowing agent may comprise a blend of 1-chloro-3,3,3- trifluoropropene and at least one pentane, such as isopentane. The 1-chloro-3,3,3- trifluoropropene may be present in at least 60 wt% based on the total weight of the blowing agent, such as in an amount of at least: 70 wt%, or 75 wt%, or 80 wt%, or 85 wt% or 90 wt% or 95 wt%. The pentane (such as isopentane) may be present in up to 40 wt% based on the total weight of the blowing agent, such as in an amount of up to: 35 wt%, or 30 wt% or 25 wt% or 20 wt% or 15 wt% or 10 wt%, or 5 wt% based on the total weight of the blowing agent.

[0099] Suitably the blowing agent comprises a blend of 1-chloro-3,3,3- trifluoropropene and at least one pentane, such as isopentane, in a weight ratio of 60:40 to 95:5, preferably in a weight ratio of 75:25 to 95:5.

[00100] Advantageously, foams produced using 1-chloro-3,3,3-trifluoropropene and isopentane as provided above demonstrate excellent thermal insulation performance, excellent flame retardancy and have low global warming potential.

[00101] Alternatively, the blowing agent may comprise a blend of a halogenated hydroolefin and a chlorinated aliphatic hydrocarbon containing 2 to 5 carbon atoms.

[00102] It has been found that a blend of chlorinated aliphatic hydrocarbon containing 2 to 5 carbon atoms, such as isopropyl chloride, and low boiling hydrocarbon can be used as a blowing agent for phenolic foam. The foams produced are essentially free of cellular defects, and give stable low thermal conductivity values. Such foams are used as insulation products for buildings and transport.

[00103] The blowing agent may comprise a chlorinated aliphatic hydrocarbon having from 2 to 5 carbon atoms. Suitably, said chlorinated aliphatic hydrocarbon having from 2 to 5 carbon atoms is at least one compound selected from the group consisting of dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, isopentyl chloride and combinations thereof.

[00104] Isopropyl chloride (2-chloropropane) can be selected for its favourable environmental characteristics. Isopropyl chloride (2-chloropropane) has been reported as having no global warming potential or ozone depletion characteristics (according to United States Environmental Protection Agency, 40 CFR Part 82. FLR-6718-2 Protection of Stratospheric Ozone. Section II Listing of Acceptable Substitutes, B Foam Blowing lb, 2-chloropropane).

[00105] When the blowing agent comprises a blend of halogenated hydroolefin and a chlorinated aliphatic hydrocarbon containing from 2 to 5 carbon atoms, suitably such a blend may comprise at least 60 wt% halogenated hydroolefin, more suitably at least 75 wt%, even more suitably, at least 85 wt% halogenated hydroolefin based on the total weight of the blowing agent. Suitably, the halogenated hydroolefin is selected from 1 - chloro-3,3,3-trifluoropropene, 1 ,3,3,3-tetrafluoropropene, 2,3,3,3-tetrafluoropropene, 1 ,1 ,1 ,4,4,4-hexafluoro-2-butene or combinations thereof. Preferably, the halogenated hydroolefin may be 1 -chloro-3,3,3-trifluoropropene.

[00106] A blend of halogenated hydroolefin and a chlorinated aliphatic hydrocarbon containing from 2 to 5 carbon atoms, suitably comprises from 5 to 40 wt% chlorinated aliphatic hydrocarbon containing from 2 to 5 carbon atoms, more suitably from 10 to 30 wt%, even more suitably, from 10 to 20 wt% chlorinated aliphatic hydrocarbon containing from 2 to 5 carbon atoms based on the total weight of the blowing agent. Suitably, the chlorinated aliphatic hydrocarbon containing 2 to 5 carbon atoms is at least one compound selected from the group consisting of dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, isopentyl chloride and combinations thereof. More suitably, the chlorinated aliphatic hydrocarbon containing 2 to 5 carbon atoms is isopropyl chloride.

[00107] A blend of halogenated hydroolefin and a chlorinated aliphatic hydrocarbon containing from 2 to 5 carbon atoms, may for example comprise 1 -chloro-3,3,3- trifluoropropene and isopropyl chloride. The 1-chloro-3,3,3-trifluoropropene may be present in at least 60 wt% based on the total weight of the blowing agent, such as in an amount of at least: 70 wt%, or 75 wt%, or 80 wt%, or 85 wt% or 90 wt% or 95 wt%. The isopropyl chloride may be present in up to 40 wt% based on the total weight of the blowing agent, such as in an amount of: 35 wt%, or 30 wt% or 25 wt% or 20 wt% or 15 wt% or 10 wt%, or 5 wt% based on the total weight of the blowing agent.

[00108] Alternatively, the blowing agent may comprise a blend (i.e. a mixture) of an aliphatic hydrocarbon containing 3 to 7 carbon atoms and a chlorinated aliphatic hydrocarbon containing from 2 to 5 carbon atoms. [00109] Optionally, said blowing agent may comprise a chlorinated aliphatic hydrocarbon containing from 2 to 5 carbon atoms in at least 60 wt% based on the total weight of the blowing agent, preferably at least 70 wt% based on the total weight of the blowing agent, more preferably at least 75 wt% based on the total weight of the blowing agent, even more preferably at least 80 wt% based on the total weight of the blowing agent.

[00110] Suitably, the aliphatic containing from 3 to 7 carbon atoms in the aforesaid blend will be present in an amount of from 1 to 40 wt% based on the total weight of the blowing agent. Preferably, in an amount of at least 5 wt% based on the total weight of the blowing agent. More preferably in an amount of at least 10 wt%, such as at least 15 wt% based on the total weight of the blowing agent, even more preferably in an amount of at least 20 wt% based on the total weight of the blowing agent.

[00111] The weight ratio of the chlorinated aliphatic hydrocarbon containing from 2 to 5 carbon atoms to the aliphatic hydrocarbon containing from 3 to 7 carbon atoms may be from 99:1 to 60:40. [00112] Suitably, the blowing agent may comprise a blend of isopropyl chloride and one or more compounds of propane, butane, pentane, hexane, heptane and isomers thereof. For example the blowing agent may comprise a blend of isopropyl chloride and at least one pentane, such as isopentane. The isopropyl chloride may be present in at least 60 wt% based on the total weight of the blowing agent, such as in an amount of at least: 70 wt%, or 75 wt%, or 80 wt%, or 85 wt% or 90 wt% or 95 wt%. The pentane (such as isopentane) may be present in up to 40 wt% based on the total weight of the blowing agent, such as in an amount of: 35 wt%, or 30 wt% or 25 wt% or 20 wt% or 15 wt% or 10 wt%, or 5 wt% based on the total weight of the blowing agent. [00113] Suitably the blowing agent comprises a blend of isopropyl chloride and at least one pentane, such as isopentane, in a weight ratio of 75:25 to 95:5.

[00114] Hydrocarbons such as isopentane and isobutane have low potential for global warming and do not deplete the ozone layer of the Earth. [00115] In addition to for example comprising a blowing agent such as a halogenated hydroolefin, a hydrocarbon, and/or a chlorinated hydrocarbon, the foam insulation core may also comprise a co-blowing agent.

[00116] A wide range of co-blowing agents may be used in accordance with the present invention. The blowing agent compositions may include one or more HFCs as co-blowing agents, such as one or more C1-C4 HFCs. For example, with respect to HFCs, the blowing agent compositions may include one or more of difluoromethane (HFC-32), fluoroethane (HFC-161 ), difluoroethane (HFC-152), trifluoroethane (HFC- 143), tetrafluoroethane (HFC-134), pentafluoroethane (HFC-125), pentafluoropropane (HFC-245), hexafluoropropane (HFC-236), heptafluoropropane (HFC-227ea), pentafluorobutane (HFC-365), hexafluorobutane (HFC-356) and all isomers of all such HFCs. Of course other materials, such as water, CO2, CFCs (such as trichlorofluoromethane (CFC-1 1 ) and dichlorodifluoromethane (CFC-12)), hydrochlorocarbons (HCCs such as dichloroethylene (preferably trans- dichloroethylene), ethyl chloride and chloropropane), HCFCs, C1-C5 alcohols (e.g. ethanol and/or propanol and/or butanol), C1-C4 aldehydes, C1-C4 ketones, C1-C4 ethers (including ethers (such as dimethyl ether and diethyl ether), diethers (such as dimethoxy methane and diethoxy methane)), and methyl formate including combinations of any of these may be included, although such components are contemplated to be not preferred in many embodiments due to negative environmental impact. [00117] Suitably, any co-blowing agent is added in such an amount that does not impair characteristics or physical properties of the foam insulation cores of the present invention. A preferred amount of the substance to be added is 0.1 to 10 % by weight, and more preferred is 0.5 to 1.5 % by weight of total amount of blowing agent in the foam insulation core. [00118] The amount of the blowing agent used in the present invention is from 1 to

20 parts by weight relative to 100 parts by weight of phenolic resin, more preferably from

5 to 15 parts, such as from 6 to 14 parts by weight per 100 parts by weight of phenolic resin. [00119] The foam insulation core may have a density of 10 kg/m ³ or more and 100 kg/m ³ or less, suitably 15 kg/m ³ or more and 70 kg/m ³ or less, more suitably 15 kg/m ³ or more and 60 kg/m ³ or less, still more suitably 15 kg/m ³ or more and 50 kg/m ³ or less. Preferably, the foam insulation core has a density of from about 20 kg/m ³ to about 45 kg/m ³ . When the density of the foam insulation core is lower than 10 kg/m ³ , the strength of the phenolic resin matrix in the core is low and evacuation of the envelope occurs having the foam insulation core enveloped therein, may lead to partial collapse of the insulation core. When the density of the foam insulation core significantly exceeds 100 kg/m ³ , thermal conduction through the phenolic resin matrix of the foam increases, and the thermal performance of the insulation product tends to be reduced.

[00120] Within the foam insulation core, the average cell diameter may be 40 pm or more and 300 pm or less, such as 50 pm or more and 250 pm or less. Suitably, the average cell diameter may be from 50 pm to 200 pm, or from 60 pm to 180 pm or less. When the average cell diameter is excessively large, gas convection in the cells and heat insulation by the cell membranes become reduced, and thus, the initial thermal insulation performance tends to deteriorate. In contrast, when the average cell diameter is excessively small, each cell membrane becomes thinner, and thus, the compression strength tends to be reduced.

[00121] The closed cell content of the foam insulation core is at least 70%. Preferably the closed cell content of the foam insulation core is at least 75%, such as at least 85%, such as at least 90%. The closed cell content of the foam insulation core may be 70% or more to 99.8% or less. For example, the closed cell content of the foam insulation core may be 75% or more, such as 80% or more, suitably 85% or more. Suitably, the closed cell content is 99.8% or less, such as 95% or less, suitably, 90% or less. When the closed cell content is below 70% the thermal performance of the foam insulation core is reduced. When the close cell content of the foam insulation core is very high, for example greater than 95%, the thermal insulation performance of the foam is improved, however, the evacuation time to form the insulation product of the invention is increased substantially. [00122] The inventors have found that the insulation product of the present invention has significantly improved long term thermal performance over conventional foam boards. By enveloping a conventional foam insulation board having a closed cell content of at least 70%, in a gas tight envelope and partially evacuating the envelope as specified herein, and hermetically sealing said envelope, an insulation product having significantly improved long term thermal performance is provided.

[00123] The envelope is a gas tight envelope, such as those employed in the manufacture of VIPs. [00124] Suitably, the envelope is a metallised film. For example, the envelope may be constructed of a metallised film formed from a polymer film coated with one or more metallised layers. The envelope may comprise a laminate formed from a plurality of layers of polymer films. For example, the envelope may be constructed from a metallised polyethylene terephthalate (PET) material. Metallised films may be formed by applying a metal layer by a metal deposition technique on the desired film. Metallised layers are typically of the order of nanometers in thickness. For example a metallised layer may be of the order of 10 nm to 50 nm thick, such as from 10 to 30 nm thick. A metallised film (which comprises a polymer film coated with typically one or more metallised layers) is often of the order of 5 to 20 microns in thickness, for example 8 to 18 microns in thickness. This is the thickness of the one or more polymer films and the one or more metallised layers taken together. Often the metal used in the metallised layers is aluminium.

[00125] As outlined above metallised film for example metallised PET can be used to create an envelope for the insulation product of the present invention. The metallised PET film, comprises a film of polyethylene terephthalate coated with at least one thin layer of metal (i.e. a metallised layer). To create a material suitable for forming an envelope, a number of layers each layer being a metallised film, such as a PET metallised film of the type described above, can be used to create the envelope. In such cases the metallised film is formed as a laminate. The metallised layers may be attached to an inner envelope layer of for example polyethylene (PE). Other suitable inner envelope inner layers include low density polyethylene (LDPE) e.g. linear low density polyethylene (LLDPE), and ultra-high molecular weight polyethylene (UHMWPE); polypropylene and ethylenevinyl alcohol (EVOH), polyvinylidene chloride (PVDC); thermoplastic urethanes; including combinations thereof including copolymers and blends thereof.

[00126] In any event, the material forming the envelope is wrapped around the foam insulation core and the envelope is then sealed to itself. This may be done by the application of heat to hermetically heat seal the envelope. The envelope may be formed from one or more film sections, for example the envelope may be formed from two film sections. The sections of the envelope to be sealed may be heated for example by heating jaws. When the envelope comprises for example two film sections, said sections may be connected by spaced-apart sealing flaps. Said sealing flaps may be arranged at a major surface of the insulation product. Said sealing flaps may be folded against a major surface in the same direction or in opposite directions - for example in a direction pointing towards each other, or in a direction pointing away from each other.

[00127] Once the foam insulation core is enveloped in the envelope, a vacuum is then applied and the position on the envelope where the vacuum is applied is finally sealed also to form a vacuum retaining envelope. The insulation product may be formed by applying a reduced pressure of 150 to 450 mBar to evacuate the envelope. For example, a reduced pressure of from 200 to 300 mBar may be applied. The reduced pressure (i.e. vacuum) may be applied for a period of from 30 to 600 seconds, such as from 60 to 300 seconds, preferably from 60 to 180 seconds. [00128] The envelope is subsequently sealed to ensure an atmosphere held within one or more open cells and/or within one or more voids of the foam insulation core has a reduced pressure relative to atmospheric pressure and relative to pressure within the closed cells, said atmosphere held within said one or more open cells and/or said one or more voids of the foam insulation core being maintained in the range of from 150 mbar to 800 mbar by the envelope.

Properties

[00129] The Suitable testing methods for measuring the physical properties of phenolic foam are described below. (i) Foam Density:

This was measured according to BS EN 1602:2013 - Thermal insulating products for building applications - Determination of the apparent density.

(ii) Thermal Conductivity:

A foam test piece of length 300 mm and width 300 mm was placed between a high temperature plate at 20°C and a low temperature plate at 0°C in a thermal conductivity test instrument (LaserComp Type FOX314/ASF, Inventech Benelux BV). The thermal conductivity (TC) of the test pieces was measured according to EN 12667:“Thermal performance of building materials and products - Determination of thermal resistance by means of guarded hot plate and heat flow meter methods, Products of high and medium thermal resistance”.

(iii) Thermal Conductivity after Accelerated Ageing:

This was measured using European Standard BS EN 13166:2012 -“Thermal insulation products for buildings - Factory made products of phenolic foam (PF)” - Specification Annex C section.4.2.3. The thermal conductivity is measured after exposing foam samples for 25 weeks at 70°C and stabilisation to constant weight at 23°C and 50% relative humidity. This thermal ageing serves to provide an estimated thermal conductivity for a time period of 25 years at ambient temperature.

Phenolic Foam (laminated)

This was measured using European Standard BS EN 13166:2012+A2:2016 -“Thermal insulation products for buildings - Factory made products of phenolic foam (PF)” - Specification Annex C section 4.2.2 Ageing conditions. Heat ageing at 70 °C: The test sample shall be aged for (175 ± 5) days at (70 ± 2) °C and then conditioned at (23 ± 2) °C and (50 ± 5) % relative humidity to constant weight as defined in EN 12429. This thermal ageing serves to provide an estimated thermal conductivity for a time period of 25 years at ambient temperature.

Phenolic Foam (Block)

This was measured using European Standard BS EN 14314:2015 -“Thermal insulation products for building equipment and industrial installations - Factory made phenolic foam (PF) products - Specification Annex B section B.4.1.2.1.1 Ageing at 70 °C. The test sample shall be aged for (175 ± 5) days at (70 ± 2) °C and then conditioned at (23 ± 2) °C and (50 ± 5) % relative humidity to constant weight as defined in EN 12429. This thermal ageing serves to provide an estimated thermal conductivity for a time period of 25 years at ambient temperature.

The thermal conductivity of an insulation product according to the invention having a foam insulation core comprising a phenolic foam is preferably 0.025 W/m.K or less.

Polvurethane/Polvisocvanurate Foam (laminated)

This was measured using European Standard BS EN 13165:2012+A2:2016 - Thermal insulation products for buildings - Factory made rigid polyurethane foam (PU) products - Specification Annex C section 4.2 Measurement of the accelerated aged value of thermal conductivity. The full product, including any facings, shall be tested. The area dimensions of the product sample shall not be less than those specified in Table A.1 of EN 12667:2001 which correspond to the product thickness, or shall be equal to the product dimensions. For products with diffusion tight facings, the maximum size of the product sample shall be 800 mm * 800 mm. The measured accelerated aged value of thermal conductivity shall be derived from the aged thermal resistance obtained after subjecting the product sample to the accelerated ageing treatment. The ageing treatment shall begin not earlier than one day after manufacture and preferably not later than 50 days after manufacture. Store the product sample at (70 ± 2) °C for (175 ± 5) days. Prepare the test specimen for thermal resistance measurement in accordance with annex C section 2. Measure the thermal resistance of the test specimen in accordance with EN 12667, EN 12939 and 5.3.2. Calculate and report the measured accelerated aged thermal conductivity value to the nearest 0.0001 W/(m.K).

Polvurethane/Polvisocvanurate Foam (block)

This was measured using European Standard BS EN 14308:2015. Thermal insulation products for building equipment and industrial installations - Factory made rigid polyurethane foam (PUR) and polyisocyanurate foam (PIR) products - Specification. The thermal conductivity is measured according annex C section 5.2: Measurement of the accelerated aged value of thermal conductivity. The full product, including any facings, shall be tested. The area dimensions of the product sample shall not be less than those specified in Table A.1 of EN 12667:2001 which correspond to the product thickness, or shall be equal to the product dimensions. For products with diffusion tight facings the maximum size of the product sample shall be 800 mm * 800 mm. The measured accelerated aged value of thermal conductivity shall be derived from the aged thermal resistance obtained after subjecting the product sample to the accelerated ageing treatment. This ageing treatment shall begin not earlier than one day after manufacture and preferably not later than 50 days after manufacture. Store the product sample at (70 ± 2) °C for (175 ± 5) days. Prepare the test specimen for thermal resistance measurement in accordance with C.2. Measure the thermal resistance of the test specimens in accordance with EN 12667 and EN 12939 and 5.3.2. Calculate and report the measured accelerated aged thermal conductivity value to the nearest 0,000 1 W/(m K).

The thermal conductivity of an insulation product according to the invention having a foam insulation core comprising a polyurethane or polyisocyanurate foam is preferably 0.025 W/m.K or less.

Polystyrene (EPS)

This was measured using European Standard BS EN 13163:2012. Thermal insulation products for buildings - Factory made expanded polystyrene (EPS) products - Specification. The Thermal conductivity is measured according to section 5.3.2 Thermal resistance and thermal conductivity Thermal resistance and thermal conductivity shall be determined in accordance with EN 12667 or EN 12939 for thick products and under the following conditions: at a mean temperature of (10 ± 0,3) °C; after conditioning in accordance with 5.2; Thermal resistance and thermal conductivity shall be determined directly at measured thickness.

Polystyrene (XPS)

This was measured using European Standard BS EN 13164:2012+A1 :2015. Thermal insulation products for buildings - Factory made extruded polystyrene foam (XPS) products - Specification Annex C section 3 Procedure for XPS foam for use with diffusion tight facing on both sides. Ageing procedure: the full size board (non-sliced) without the facings was stored at (23 ± 2) °C and (50 ± 5) % relative humidity for a time period of 60 days after production. Then a test specimen was cut with the dimensions of 500 mm x 500 mm and measure the thermal conductivity in accordance with EN 12667 or EN 12939 for thick products and under the following conditions:

— at a mean temperature of (10 ± 0,3) °C; — after conditioning in accordance with 5.2;

— taking into account the effect of aging according to Annex C. and with 5.3.2.

The thermal conductivity of an insulation product according to the invention having a foam insulation core comprising a polystyrene foam is preferably 0.025 W/m.K or less.

(iv) JDH : The pH was determined according to the standard BS EN 13468.

(v) Closed cell Content:

The closed cell content may be determined using gas pycnometry. Suitably, closed cell content may be determined according to ASTM D6226 test method.

(vi) Friability: Friability is measured according test method ASTM C421 - 08(2014).

(vii) Average cell diameter A piece of foam was roughly cut measuring approximately 20 mm x 10 mm. from one coated surface to the other. From this piece the surfaces were trimmed with a razor blade to approximately 8 mm square. The foam was then snapped sharply to reveal a clean surface and the majority of the sample was removed to leave a thin (-1 mm) slice. The slice was fixed onto an aluminium sample stub using a double sided conducting sticky tab.

The samples were then given a thin (-2.5 Angstroms) conducting coat of gold/palladium using a Bio-Rad SC500 sputter coater. The reason for coating the sample is (a) to add a conducting surface to carry the electron charge away and (b) to increase the density to give a more intense image. At the magnifications involved in this study the effect of the coating is negligible.

The samples were imaged using an FEI XL30 ESEM FEG Scanning Electron Microscope under the following conditions: 10kV accelerating voltage, working distance -10mm, spot size 4, and Secondary Electron Detector. Images were saved at the following magnifications x350, x1200 and x5000 and saved as .tiff files to disc. The images at x350 show the general size distribution of the cells and higher magnifications at x1200 and x5000 show the nature of the cell surfaces.

Images acquired at x350 magnification for both samples typically show a size range of -100 to 200 microns. In the preparation of the foam samples for evaluation by electron microscopy, the manual snapping of the foam sample - to create a surface to examine - can induce some damage at the cell walls.

The images collected at x1200 and x5000 magnification are substantially free of defects and holes.

(viii) Viscosity The viscosity of a resin employed in the manufacture of a foam insulation core of the present invention may be determined by methods known to the person skilled in the art for example with a Brookfield viscometer, for example a Brookfield RTV Viscometer having a #2 spindle at 20 rpm and at a specified temperature.

(ix) Internal Pressure in the open cells of the insulation product The internal pressure within the open cells of the insulation product may be determined using an envelope lift-off procedure. The panel is placed in a vacuum chamber and the pressure in the chamber is diminished until the envelope lifts off the foam insulation core surface. This can be recorded visually or by using photo electric sensors. The point at which the envelope lifts off the foam insulation core indicates the point at which the pressure in the vacuum chamber is lower than that in the open cells of the insulation product. A schematic of the envelope lift off procedure is shown in Figure 2.

EXAMPLES Example 1

[00130] Foam Core A was formed in accordance with the method described in Example 1 of W02007029221 , except the blowing agent employed was an 80:20 (by weight) blend of isopropyl chloride and isopentane.

[00131] The resulting foam has an initial thermal conductivity of 19.6 W/m.K, a density of 28 kg/m ³ , a compressive strength of 130 kPa and a closed cell content of 99%.

Foams made in accordance with example 1 , were employed to form insulation products in accordance with the present invention labelled insulation product A in Table 1 below.

[00132] The foam of Example 1 was wrapped in a gas tight envelope, comprising a metallised PET film, and a vacuum of 200 mbarwas applied fora period of 180 seconds and the envelope was hermetically sealed, to provide a foam insulation product according to the present invention, e.g. foam insulation

Example 2 Phenolic Resin B [00133] The phenolic resin employed is commercially available liquid phenol- formaldehyde resin supplied by Sumitomo Bakelite under the trade name R330U. This resin has a viscosity of 7000 to 14000 cP at 25°C, a weight average molecular weight of 700 to 2000, and a pH of 6.5 to 7.5. R330U resin contains from 2 wt% to 4 wt% free phenol and less than 1 wt% free formaldehyde based on the total weight of the resin. R330U resin has a water content of 11 to 14 wt% (measured by Karl Fisher analysis) based on the total weight of the resin. R330U resin contains 3 to 5 wt% plasticiser and 2 to 5 wt% surfactant as previously described herein, based on the total weight of the resin. R330U has a number average molecular weight of from 330 to 700.

[00134] 100 parts by weight of Resin B was mixed with 12 parts by weight of blowing agent comprising 85:15 (wt ratio) of 1233zd and isopentane. To this mixture was added 22 parts by weight of Naxcat XT92 acid catalyst and at a temperature of 17°C. The mixture was applied to a moving facing.

[00135] A second facing is applied to the rising foamable phenol resin composition applied to the first facing and the foam sandwich formed was introduced into a first oven having a slat-type double conveyor heated to 78 °C. The foam residence time in the conveyor was at least 3 minutes, the foam sandwich is cut to a desired length and the resulting cut length of foam was then post cured for a period of 12 hours at 70°C.

[00136] The resulting foam has an initial thermal conductivity of 0.0168 W/m.K, a density of 27 kg/m ³ , a compressive strength of 140 kPa and a closed cell content of 99%. [00137] Foams made in accordance with example 2 (foam core B), were employed to form insulation products in accordance with the present invention labelled insulation product B in Table 1 below.

[00138] The foam of Example 2 was wrapped in a gas tight envelope, comprising a metallised PET film, and a vacuum of 200 mbarwas applied fora period of 180 seconds and the envelope was hermetically sealed, to provide a foam insulation product according to the present invention, e.g. foam insulation

[00139] Figure 1 shows a cut-away perspective view of an insulation product (1 ) according to the present invention. The insulation product comprises a foam insulation core (101 ), having an upper surface (102) a lower surface (103) and sides (104). The internal structure of the foam insulation core is depicted (201 ) in Figure 1. The foam insulation core comprises a plurality of closed cells (202) and a plurality of open cells (203). A blowing agent is retained within the closed cells (202). The foam insulation core (101 ) shown in Figure 1 , is a phenolic foam, though the skilled person will appreciate that other foam insulation cores may be employed. The phenolic foam insulation core (101 ) has a density of 27 kg/m ³ , a closed cell content of 99%, a compressive strength of

140 kPa, and an initial thermal conductivity of 0.0168 W/rn-K. The blowing agent retained within the closed cells of the phenolic insulation core comprises 1-chloro-3,3,3- trifluoropropene and isopentane.

[00140] The phenolic foam insulation core was formed by foaming and curing a phenolic resin composition that comprises, a phenolic resin, a surfactant, a blowing agent and a curing catalyst.

[00141] An envelope (301 ) envelops the foam insulation core. The envelope comprises a metallised PET film. As shown in the enlarged view (401 ) the envelope comprises three metallised films (402). Each metallised film (402) is a metallised plastic layer of for example metallised PET. Suitably, metallised polypropylene (PP) or metallised EVOH (ethyl vinyl alcohol) may also be employed. The metallised films (402) are attached to an envelope inner layer (403). The envelope inner layer (403) is typically a thermoplastic polymer, such as polyethylene. Suitable alternatives include low density polyethylene (LDPE) e.g. linear low density polyethylene (LLDPE), and ultra-high molecular weight polyethylene (UHMWPE); polypropylene and ethylenevinyl alcohol (EVOH), polyvinylidene chloride (PVDC); thermoplastic urethanes; including combinations thereof including copolymers and blends thereof.

[00142] The blowing agent retained within the closed cells exerts an outward pressure on the internal walls of the closed cells. The initial pressure in the closed cells is higher than the pressure in the open cells and/or voids which is maintained by the envelope. Over time an equilibrium between the pressure in the closed and open cells may be reached.

[00143] The atmosphere held within one or more of the open cells (203) and/or within one or more voids (204) of the foam insulation core (101 ) has a reduced pressure relative to atmospheric pressure, said atmosphere held within said one or more open cells and/or said one or more voids of the foam insulation core being maintained in the range of from 150 mbar to 800 mbar by the envelope (301 ). Preferably, the atmosphere held within the one or more open cells and/or the one or more voids of the foam insulation core is in the range of from 200 mbar to 500 mbar. Table 1

[00144] The words“comprises/comprising” and the words“having/including” when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[00145] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. 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 sub-combination.