PHENOLIC FOAM AND METHOD OF MANUFACTURE THEREOF

Abstract

A phenolic foam and method for manufacturing same are described herein. The foam is formed from a foamable phenolic resin composition, and a blowing agent, the phenolic foam comprising 1 to 5% by weight of red phosphorus based on the weight of the phenolic foam wherein said phenolic foam has a density of from 10 kg/m.sup.3 to 100 kg/m.sup.3, a closed cell content of at least 85% as determined in accordance with ASTM D6226 and wherein said foam has a FIGRA.sub.0.2 MJ of 120 W/s or less, when measured according to EN13823 and a thermal conductivity of 0.023 W/m.K or less, at 10° C., in accordance with EN 13166:2012. The foam has excellent thermal insulation performance and excellent fire performance.

Claims

1-37. (canceled)

38. A phenolic foam formed from a foamable phenolic resin composition, and a blowing agent, the phenolic foam comprising 1 to 5% by weight of red phosphorus based on the weight of the phenolic foam, the phenolic foam has a density of from 10 kg/m.sup.3 to 100 kg/m.sup.3, a closed cell content of at least 85% as determined in accordance with ASTM D6226 and the foam has a FIGRA.sub.0.2 MJ of 120 W/s or less, when measured according to EN13823 and a thermal conductivity of 0.023 W/m.K or less, at 10° C., in accordance with EN 13166:2012.

39. The phenolic foam according to claim 38, wherein the phenolic foam comprises 2 to 5% by weight of red phosphorus based on the weight of the phenolic foam.

40. The phenolic foam according to claim 38, wherein the blowing agent comprises at least one of the following: at least one saturated or unsaturated C.sub.3-C.sub.6 hydrocarbon; at least one saturated or unsaturated C.sub.3-C.sub.6 compound that is substituted at least once by one or more of fluorine and chlorine for example isopropyl chloride.

41. The phenolic foam according to claim 38, wherein the blowing agent comprises at least one of: (i) isopropyl chloride or (ii) a saturated C.sub.3-C.sub.6 hydrocarbon such as pentane for example isopentane; or (iii) a blend of isopropyl chloride and a saturated C.sub.3-C.sub.6 hydrocarbon such as pentane for example isopentane.

42. The phenolic foam according to claim 38, wherein the foam has a FIGRA.sub.0.2 MJ of 110 W/s or less, for example 100 W/s or less, such as 90 W/s or less when measured according to EN13823.

43. The phenolic foam according to claim 38, wherein the blowing agent comprises at least one of hydrofluoroolefin or chlorinated hydrofluoroolefin.

44. The phenolic foam according to claim 43 wherein the blowing agent further comprises at least one of the following: at least one saturated or unsaturated C.sub.3-C.sub.6 hydrocarbon; at least one saturated or unsaturated C.sub.3-C.sub.6 compound that is substituted at least once by one or more of fluorine and chlorine atoms for example isopropyl chloride.

45. The phenolic foam according to claim 43, wherein the blowing agent comprises a blend of at least one of hydrofluoroolefin or chlorinated hydrofluoroolefin with a C.sub.3-C.sub.6 hydrocarbon such as pentane for example isopentane.

46. The phenolic foam according to claim 38, wherein the foam has a FIGRA.sub.0.2 MJ of 100 W/s or less, for example 90 W/s or less, such as 80 W/s or less, such as 70W/s or less when measured according to EN13823.

47. The phenolic foam according to claim 38, wherein the red phosphorus is in micronized form.

48. The phenolic foam according to claim 38, wherein the red phosphorous is in particulate form with a number average particle size in the range from 0.1 μm to 25 μm, for example 0.25 μm to 15 μm, such as 0.5 μm to 10 μm.

49. The phenolic foam according to claim 38, wherein the foam has a total heat release of 7.5 MJ or less, such as 7.0 MJ or less, or 6.5 MJ or less, or 6.25 MJ or less, or 6.0 MJ or less, or 5.75 MJ or less, or 5.5 MJ or less, or 5.25 MJ or less, or 5.15 MJ or less, or 5.0 MJ or less, or 4.8 MJ or less, or 4.6 MJ or less, or 4.4 MJ or less, when measured according to EN13823.

50. The phenolic foam according to claim 38, wherein the cells of the foam have an average cell diameter in the range of from 50 to 250 μm, suitably in the range of from 80 to 180 μm.

51. The phenolic foam according to claim 38, wherein said foam has a thermal conductivity of 0.020 W/mK or less, suitably of 0.018 W/mK or less, preferably 0.0175 W/mK or less, or 0.0170 W/mK or less, or 0.0165 W/mK or less, 0.0162 W/mK or less when measured at a mean temperature of 10° C., in accordance with EN 13166:2012.

52. The phenolic foam according to claim 38, wherein the foam having a limiting oxygen index of 34% or more, optionally 35% or more, suitably 36% or more, such as 37% or more as determined in accordance with ISO 4589-2.

53. The phenolic foam according to claim 38, wherein the foam has a stable moisture content of from 3% to 8%, for example 3% to 5%, by weight when determined at (23±2)° C. and a relative humidity of (50±5)% in accordance with EN1249:1998.

54. The phenolic foam according to claim 43, wherein the at least one chlorinated hydrofluoroolefin is selected from 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) and 1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd).

55. The phenolic foam according to claim 43, wherein the at least one hydrofluoroolefin comprises 1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz).

56. The phenolic foam according to claim 38, wherein the hydrocarbon comprises at least one butane, suitably isobutane, and/or at least one pentane, for example isopentane.

57. A phenolic foam formed by foaming and curing a phenolic resin foamable composition comprising a phenolic resin, a surfactant, an acid catalyst, a blowing agent, and 1 to 5% by weight of red phosphorus based on the weight of the phenolic foam, the phenolic foam has a density of from 10 kg/m.sup.3 to 100 kg/m.sup.3, a closed cell content of at least 85% as determined in accordance with ASTM D6226 and the foam has a FIGRA.sub.0.2 MJ of 120 W/s or less (such as 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 according to EN13823 and the phenolic foam has a thermal conductivity of 0.023 W/m.K or less, at 10° C., in accordance with EN 13166:2012.

58. The phenolic foam according to claim 57, wherein the at least one chlorinated hydrofluoroolefin is selected from 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) and 1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd).

59. The phenolic foam according to any claim 57, wherein the at least one hydrofluoroolefin comprises 1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz).

60. The phenolic foam according to claim 57, wherein the at least one C.sub.3-C.sub.6 hydrocarbon comprises at least one butane, suitably isobutane, and/or at least one pentane, optionally isopentane.

61. The phenolic foam according to claim 38, wherein the phenolic resin composition comprises a phenolic resin that has a weight average molecular weight of from about 700 to about 2000, and/or wherein the phenolic resin has a number average molecular weight of from about 330 to about 800, such as from about 350 to about 700.

62. The phenolic foam according to claim 38, wherein the phenolic resin has a molar ratio of phenol groups to aldehyde groups in the range of from about 1:1 to about 1:3, suitably from about 1:1.5 to about 1:2.3.

63. The phenolic foam according to claim 38, wherein the phenolic resin has a viscosity of from about 2,500 mPa.Math.s to about 18,000 mPa.Math.s when measured at 25° C., such as from about 2500 mPa.Math.s to about 16,000 mPa.Math.s when measured at 25° C. for example from about 4,000 mPa.Math.s to about 8,000 mPa.Math.s when measured at 25° C.

64. The phenolic foam according to claim 38, 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 phenolic resin.

65. The phenolic foam according to claim 38, wherein the foam has a density from 34.5 kg/m.sup.3 to 40 kg/m.sup.3; such as from 35 kg/m.sup.3 to 39 kg/m.sup.3, for example from 36 kg/m.sup.3 to 38 kg/m.sup.3.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0109] FIG. 1 shows a scanning electron micrograph of a closed cell phenolic foam.

[0110] FIG. 2 shows heat development as a function of time in a real fire situation

[0111] FIG. 3 is a schematic of the SBI test set-up of EN13823.

[0112] FIG. 4 shows the impact of temperature on the thermal conductivity (lambda λ value) of phenolic foams blown with three different weight ratio blends of 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) and isopentane.

[0113] FIG. 5 is a representative SEM image of a phenolic foam with red phosphorus particles dispersed therein and having the number average particle size set out above and present in the amount stated above. This foam is the same as that of Example 3 below.

DEFINITIONS

[0114] 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”.

[0115] The phrase “Y 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.

[0116] 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/expand a resin to form a foam.

Properties

[0117] Suitable testing methods for measuring the physical properties of phenolic foam are described below. [0118] (i) Foam Density: [0119] This was measured according to BS EN 1602:2013—Thermal insulating products for building applications—Determination of the apparent density. [0120] (ii) Thermal Conductivity of the Foam: [0121] 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”. [0122] (iii) Thermal Conductivity of the Foam after Accelerated Ageing: [0123] 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 period of 25 years at ambient temperature. Alternatively, aged thermal conductivity may be measured after exposing foam samples for 2 weeks at 110° C. and stabilisation to constant weight at 23° C. and 50% relative humidity. [0124] (iv) pH [0125] The pH was determined according to the standard BS EN 13468. [0126] (v) Closed cell Content: [0127] The closed cell content may be determined using gas pycnometry. Suitably, closed cell content may be determined according to ASTM D6226 test method. [0128] (vi) Foam Friability: [0129] Friability is measured according to test method ASTM C421-08(2014). [0130] (vii) Imaging Foam [0131] A piece of foam was roughly cut measuring approximately 20 mm×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 most of the sample was removed to leave a thin (˜1 mm) slice. [0132] The slice was fixed onto an aluminium sample stub using a double sided conducting sticky tab. [0133] 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. [0134] The samples were imaged using an FEI XL30 ESEM FEG Scanning Electron Microscope under the following conditions: 10 kV accelerating voltage, working distance ˜10 mm, spot size 4, and Secondary Electron Detector. Images were saved at the following magnifications ×350, ×1200 and ×5000 and saved as .tiff files to disc. The images at ×350 show the general size distribution of the cells and higher magnifications at ×1200 and ×5000 show the nature of the cell surfaces. [0135] Images acquired at ×350 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. [0136] The images collected at ×1200 and ×5000 magnification are substantially free of defects and holes. [0137] (viii) Average Cell Diameter [0138] A flat section of foam is obtained by slicing through the middle section of the thickness of the foam board in a direction running parallel to the top and bottom faces of a foam board. A 50-fold enlarged photocopy is taken of the cut cross section of the foam. Four straight lines of length 9 cm are drawn on to the photocopy. The number of cells present on every line is counted and the average number cell number determined according to JIS K6402 test method. The average cell diameter is taken as 1800 μm divided by this average number. [0139] (ix) Resin Viscosity [0140] The viscosity of a resin employed in the manufacture of a foam of the present invention may be determined by methods known to the person skilled in the art for example using a Brookfield viscometer (model DV-II+Pro) with a controlled temperature water bath, maintaining the sample temperature at 25° C., with spindle number S29 rotating at 20 rpm or appropriate rotation speed and spindle type or suitable test temperature to maintain an acceptable mid-range torque for viscosity reading accuracy. [0141] (x) % Water Content of Phenolic Resin

[0142] To dehydrated methanol (manufactured by Honeywell Speciality Chemicals), the phenol resin was dissolved in the range of 25% by mass to 75% by mass. The water content of the phenol resin was calculated from the water amount measured for this solution. The instrument used for measurement was a Metrohm 870 KF Titrino Plus. For the measurement of the water amount, Hydranal™ Composite 5, manufactured by Honeywell Speciality Chemicals was used as the Karl-Fischer reagent, and Hydranal™ Methanol Rapid, manufactured by Honeywell Speciality Chemicals, was used for the Karl-Fischer titration. For measurement of the titre of the Karl-Fischer reagent, Hydranal™ Water Standard 10.0, manufactured by Honeywell Speciality Chemicals, was used. The water amount measured was determined by method KFT IPol, and the titre of the Karl-Fischer reagent was determined by method Titer IPol, set in the apparatus. [0143] (xi) Phosphorus Content in Phenolic Foam [0144] The concentration of phosphorus in phenolic foam can be determined by any suitable analytical method. One method for determining the concentration of phosphorus in phenolic foam is the use of inductively coupled plasma optical emission spectrometry (ICP-OES). The procedure for determining the concentration of phosphorus with ICP-OES is as follows: [0145] Prior to use, all glass and plasticware was acid washed in 1.5M hydrochloric acid overnight before being rinsed with MilliQ (grade 1 deionised water). All reagents were Primar Plus Trace Metal Grade (Fisher Scientific). A shredded foam sample was dried in an oven for 1 hr at 70° C. before being cooled in a desiccator. 0.1 g (+/−0.01 g) of foam was weighed out into a 55 ml Teflon microwave digestion tube. To the tube, 4.5 ml of 68% nitric acid, 1 ml of 37% hydrochloric acid and 0.5 ml of 30% hydrogen peroxide were added and the sample was allowed to react for 10 minutes and for the effervescence to subside. Replicates of the sample and a procedural blank, consisting of the above reagents and no foam, were processed in parallel. The tubes were sealed with a PTFE pressure seal, capped and transferred to a CEM Mars 5 digestion microwave system fitted with a sample carousel. The microwave digester was heated to 190° C. over 10 minutes and held at 190° C. for a further 15 minutes before being allowed to cool to room temperature. The digested sample was transferred into a 15 ml centrifuge tube and a 1 ml aliquot was subsequently diluted with 4 ml of MilliQ water to achieve a solution of 20% acid concentration. An aliquot of this solution was then diluted down to 2% acidity and filtered through a 0.45 μm surfactant-free cellulose acetate filter. The filtered sample was run for phosphorus on a Thermo ICAP Duo ICP 6300 ICP-OES elemental analyser. The instrument was calibrated using a seven-point calibration in the range 0.5-20 mg/l. [0146] Instrument precision was measured by 3 injections of the same sample and the relative standard was found to be 0.244% of the mean. All samples were blank-corrected and the results were as follows:

TABLE-US-00001 TABLE A % Phosphorus in Cured Total P conc. % Phosphorus by Phenol Foam Results (mg/g) weight in foam Table 6 Examples 1 & 2 Foam Sample (i) 28.629 2.8629 Table 6 Examples 1 & 2 Foam Sample (ii) 27.607 2.7607 Table 6 Examples 1 & 2 Foam Sample (iii) 28.984 2.8984 Mean concentration 28.407 2.8407 [0147] (xii) Fire Performance of the Foam

[0148] A schematic of the SBI test set-up of EN13823 is shown in FIG. 3. The test samples consist of two walls (formed of the material to be tested) mounted to form a vertical 90° corner. The dimensions of the walls are as follows: [0149] Short wall—1.5 m high by 0.5 m long [0150] Long wall—1.5 m high by 1.0 m long

[0151] A propane burner is positioned in the base of the corner formed by the specimen, with a horizontal separation of 40 mm between the edge of the burner and the lower edge of the specimen.

[0152] The rate of air flow extraction is set at 0.6 m.sup.3/s. A sampling probe is installed in the extraction duct, to measure the concentration of CO.sub.x and O.sub.2 of the fire effluent gases passing through. The rate of heat release is continuously calculated by means of the Oxygen Consumption Method. The obscuration of light caused by the smoke in the fire effluent passing through the exhaust duct is determined by a white light lamp and photocell system.

[0153] At the outset of the test procedure, baseline data (e.g. temperature at various points in the test set-up) are recorded for three minutes. The burner is then ignited and a 30 kW flame impinges upon the test specimen for 21 minutes. The performance of the specimen is evaluated over a period of 20 minutes.

[0154] Fire growth rate (FIGRA) indices are defined as the maximum of the quotient of the average heat release as a function of time:

[00001]$\mathrm{FIGRA}=\left(1000\right)\times \max .Math.\frac{{\mathrm{HRR}}_{\mathrm{av}}\left(t\right)}{\left(t-300\right)}$ [0155] FIGRA is the fire growth rate index, in watts per second; [0156] HRRav(t) is the average of heat release rate for HRR(t) in kilowatts; [0157] HRR(t) is the heat release rate of the specimen at time t, in kilowatts; [0158] Max. [a(t)] is the maximum of a(t) within the given time period [0159] NOTE: Consequently, specimens with an HRRav value of not more than 3 kW during the total test period or a THR value of not more than 0.2 MJ over the total test period, have a FIGRA.sub.0.2 MJ equal to zero. Specimens with an HRR.sub.av value of not more than 3 kW during the total test period or a THR value of not more than 0.4 MJ over the total test period, have a FIGRA.sub.0.4 MJ equal to zero.

[0160] The quotient is calculated only for that part of the exposure period in which threshold levels for HRR.sub.av and THR have been exceeded. If one or both threshold values of a FIGRA index are not exceeded during the exposure period, that FIGRA index is equal to zero. Two different THR-threshold values are used, resulting in FIGRA.sub.0.2 MJ and FIGRA.sub.0.4 MJ. The moments in time that the threshold values are exceeded are defined as: [0161] (a) First moment after t=300 s at which HRR.sub.av>3 kW [0162] (b) First moment after t=300 sat which THR>0.2 MJ and/or THR>0.4 MJ

[0163] The total heat release (THR) is measured over the first 10 minutes (THR.sub.600 s) after ignition of the burner.

[0164] EN13823 defines smoke growth rate index (SMOGRA) as the maximum of the quotient for the average smoke production rate as a function of time. The quotient is calculated only for that part of the exposure period in which threshold levels of average smoke production rate SPR.sub.av and total smoke production rate TSP have been exceeded. If one or both threshold values are not exceeded during the exposure period, SMOGRA is equal to zero.

[00002]$\mathrm{SMOGRA}=\left(10000\right)\times \max .Math.\frac{{\mathrm{SPR}}_{\mathrm{av}}\left(t\right)}{\left(t-300\right)}$ [0165] SMOGRA is the smoke growth rate index in square metres per square second; [0166] SPR.sub.av(t) is the average smoke production rate SPR(t) of the specimen in square metres per second; [0167] SPR(t) is the smoke production rate of the specimen, in square metres per second; [0168] max. [a(t)] is the maximum of a(t) within the given time period; [0169] TSP(t) is the total smoke production of the specimen in the first 600 s of the exposure period within 300 s≤t≤900 s (m2). [0170] Note: Consequently, specimens with a SPR.sub.av value of not more than 0.1 m.sup.2/s during the total test period or a TSP value of not more than 6 m.sup.2 over the total test period have a SMOGRA value equal to zero.

[0171] The moments in time that the threshold values are exceeded are defined as: [0172] (a) First moment after t=300 s at which SPR.sub.av>0.1 m.sup.2/s [0173] (b) When “t” is between 300 s to 1500 s, TSP(t)>6 m.sup.2

[0174] The SMOGRA index is determined during the full duration of the test. The total smoke production TSP.sub.600 is measured over the first 10 minutes after burner ignition (i.e. between 300 and 900 seconds).

[0175] As outlined above, the SBI test is comparable to a waste-paper basket on fire in the corner of a room.

[0176] Examples of the fire performance of different commercial available foam insulation materials tested according EN13823 is given in Table 1.

TABLE-US-00002 TABLE 1 EN 11925-2 Burner EN13823 (test performed with impinges Com- Declared foam core, no facings) on foam pressive Blowing Lambda FIGRA FIGRA for 15 FOAM Strength Agent Value (0.2 MJ) (0.4 MJ) THR SMOGRA TSP seconds Euro- TYPE (kPa) Used (W/m .Math. K) (W/s) (W/s) (MJ) (m.sup.2/s.sup.2) (m.sup.2) (mm) class XPS (high 700 unknown 0.035 to <150 E compressive 0.037 strength) XPS (low 200 unknown 0.033 to >150 F compressive 0.037 strength) PIR (1) 150 Cyclo- 0.022 697 298 4.75 61 62 <150 D pentane/ isopentane PIR (2) 150 Cyclo- 0.022 736 348 5.36 47 67 <150 D pentane/ isopentane PIR (3) 150 HCFO- 0.019 1102 815 5.20 46 46 <150 E 1233zd(Z) Phenolic 100 Isopropyl 0.020 232 128 4.4 1 40 <150 C chloride/ isopentane Note: To test the fire performance of the foam core, the facer is removed and the surface is sanded to remove any remaining facer materials, which can influence the test. The boards are mounted in line with the test standard EN 15715 to the incombustible substrate prior to testing.

[0177] Before the test on the foam core, the foam sample is conditioned at 23° C. 50% Relative Humidity in accordance with EN13823 and then the facer was peeled from the foam surface as carefully as possible. Any remaining facer is removed carefully by sanding with a very fine abrasive paper.

[0178] Phenolic foams typically have the best fire rating of any foam insulation products. The fire retardancy of a foam will be impacted by the nature of the blowing agent used to expand the foam and which is retained within the cells of the foam. As discussed above, the thermal insulating performance of a foam also depends significantly on the blowing agent, and the thermal conductivity thereof. Chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs) represent a class of blowing agent with the highly desirable combination of low thermal conductivity and excellent fire performance. However, the use of such blowing agents is being phased out due to their negative environmental impact, in particular, their high ozone depletion potential and high global warming potential. Hydrocarbon blowing agents, which have low environmental impact, have been employed as a replacement blowing agent for CFCs and HFCs but hydrocarbons are inherently higher in thermal conductivity than CFCs or HFCs and they are also flammable. Over the last 10 years, hydrofluoroolefins and chlorinated hydrofluoroolefins have emerged as a class of blowing agent with a combination of low thermal conductivity, good fire performance and low environmental impact.

[0179] Hydrofluoroolefins (HFOs) and hydrochlorofluoroolefins (HCFOs) are unsaturated short-chain haloolefins, which have been introduced as alternatives to saturated hydrofluorocarbons (HFCs) as foam blowing agents, due to their ultra-low GWP (Global Warming Potential) and zero ODP (Ozone Depletion Potential).

[0180] With the introduction of HFOs (hydrofluoro olefins), and hydrochlorofluoroolefins (HCFOs), a range of blowing agents is now available to improve fire performance. A key advantage of these particular blowing agents is their low thermal conductivity in the gas phase and favourable environmental performance.

[0181] HCFOs are also preferred as a blowing agent, due to their low thermal conductivity in the gas phase and their compatible solubility with phenolic resins.

[0182] HFOs tend to have slightly higher thermal conductivity values in the gas phase than HCFOs.

[0183] Table 2 below gives an overview of the main blowing agents referred to in this patent.

TABLE-US-00003 TABLE 2 Thermal Con- solu- vapour ductivity bility MW pressure (W/m .Math. K) dipole in Commercial name/ (g/ BP (bar, at moment water Flam- IUPAC name mol) ° C. 20° C.) 25° C. (D) (g/kg) mability ODP GW Hydro(chloro) fluoroolefins HCFO-1224yd(Z) 148 14 1.51* 12.2 0.34 none 0 <1 (Z)-1-Chloro-2,3,3, 3,-Tetrafluoro-propene HFO-1336mzz(Z) 164 33 0.72 10.7 3.19 3.8 none 0 5 cis-1,1,1,4,4,4- hexafluoro-2-butene HFO-1336mzz(E) 164 7.5 2 11.5 0 7 (E)-1,1,1,4,4,4- Hexafluoro-2-butene HCFO-1233zd(E) 131 19 1.06 10.5 1.44 1.9 none 0 5 trans-1-chloro-3,3, 3-trifluoropropene HFO-1234ze(E) 114 −19 4.9 13 1.44 0.037 none 0 6 trans-1,3,3,3- tetrafluoro-propene HFO-1234yf 114 −30 6.1 14 2.54 0.2 yes 0 4 2,3,3,3-tetrafluoro- propene Perfluorochemicals Perfluoro(4-methyl- 300 49 0.355 none 0 2-pentene) Perfluoro(4-methyl- 2-pentene) Perfluoropropene 150 −28 6.3 0 none 0 0.25 Hexafluoro-propene Perfluoroethylene 100 −76.3 32.4 yes 0 0.02 Tetrafluoro-ethene Perfluoro-1,3-butadiene 162 6 0.8 0 yes 0 0.03 Hexafluoro-1,3-butadiene Perfluorocyclo-hexene 262 52 0 Decafluoro-cyclohexene Perfluorobenzene 186 80.1 0.11 high 0 Hexafluorobenzene CFC-11 137 23.7 0.883 8.2 4.1 1.1 none 1 475 trichlorofluoromethane hydrochloro- fluorocarbons HCFC-141b 117 32.2 0.69 9.8 4.32 4 none 0.1 725 1,1-dichloro-1- fluoroethane Hydrofluorocarbons HFC-134a 102 −26.2 4.826 12 2.06 1.5 none 0 143 1,1,1,2-tetrafluoroethane HFC-143a 84 −47.6 >10 2.34 0.76 yes 0 447 1,1,1-trifluoroethane HFC-245fa 134 15.3 1.227 12.2 1.57 7.18 none 0 103 1,1,1,3,3-penta- fluoropropane HFC-152a 66 −24.7 5.13 18.2 2.26 0.29 yes 0 124 1,1-difluoroethane Hydrocarbons Isopentane 72 27.8 0.99 14.5 0 0 yes 0 5 Methylbutane Cyclopentane 70 49.3 0.338 12 0 0 yes 0 <0.1 Cyclopentane Isobutane 58 −12 3.1 14.3 0 0.05 yes 0 3 Methylpropane n-pentane 72 36 0.648 14.4 0.01 0 yes 0 <15 n-Pentane n-hexane 86 68.5 0.18 23.4 0 0.01 yes 0 3 n-Hexane Neohexane 86 49.7 0.37 18 0 0 yes 0 2,2-Dimethylbutane Diisopropyl 86 57.9 0.26 18.8 0 0 yes 0 2,3-Dimethylbutane indicates data missing or illegible when filed

[0184] When considering what blowing agent to use when manufacturing a foam, the end use application of the foam must be taken into consideration, and in general, the properties of the blowing agent must align with the end use application. Important properties of a given blowing agent which may be considered during the selection process include: the thermal conductivity in the gas phase, the boiling point, compatibility with the chemical matrix, flammability, toxicity and price.

[0185] One of the most important criteria is the thermal conductivity (or lambda) of each blowing agent component (comp). A simple model to estimate the insulation value of a binary gas mixture containing component A and component B is:

[00003]${\lambda }_{\mathrm{mix}}=0.5*\frac{{\lambda }_{\mathrm{compA}}*{\lambda }_{\mathrm{compB}}}{{\lambda }_{\mathrm{compA}}*X_{\mathrm{compB}}+{\lambda }_{\mathrm{compB}}{X}_{\mathrm{compA}}}+0.5*\left({\lambda }_{\mathrm{compA}}*X_{\mathrm{compA}}+{\lambda }_{\mathrm{compB}}{X}_{\mathrm{compB}}\right)$

where: [0186] λ.sub.mix is the thermal conductivity of the mixture of the blowing agent components A and B [0187] λ.sub.comp A is the thermal conductivity of blowing agent component A [0188] λ.sub.comp B is the thermal conductivity of blowing agent component B [0189] λ.sub.comp A is weight fraction of component A in the blowing agent mixture [0190] λ.sub.comp B is weight fraction of component B in the blowing agent mixture.

[0191] This model can also be used to estimate the thermal conductivities of more complex blowing agent mixtures by initially calculating the thermal conductivity of two components in a blend of blowing agents and then employing the λ.sub.mix for the binary blend as a lambda input value for the mixture of the binary blend with a third blowing agent.

[0192] The cell gas inside a foam cell can start to condense when the foam temperature is at or below the boiling point of the blowing agent. The standard average temperature (T.sub.mean) for lambda measurement of a foam according to the European standard EN 12667 for example is 10° C. In the heat flow meter, the temperature settings of the plates are 10° C. above and below this T.sub.mean. The point at which the cell gas starts to condense will have an important impact on the thermal conductivity of the product.

[0193] FIG. 4 shows the impact of the temperature on the thermal conductivity of phenolic foams blown with three different weight ratio blends of 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) and isopentane.

[0194] Blowing agents are generally selected to try to avoid condensation above 10° C. in order to prevent condensation in the cells of the foam when in use. Condensation causes a reduction in insulation performance.

[0195] Blowing agents can also be categorized in terms of flammability. ISO817 classifies blowing agents in terms of their flammability.

TABLE-US-00004 TABLE 3 Class Category Examples 1 Non-flammable HFO-1336mzz(Z) HCFO-1233zd(E) 2L Low flammability HFO-1234yf HCFO-1234ze(E) HFC-32 2 Flammable HFC-152a 3 High flammability Propane isomers Butane isomers Pentane isomers Isopropyl chloride

[0196] There are several main parameters that characterize the level of flammability (1, 2L, 2, and 3) of a blowing agent including the burning velocity (BV), the upper and lower flammability limits (UFL and LFL), the minimum ignition energy (MIE), and the heat of combustion (HOC): [0197] 1) BV, burning velocity: is the speed at which a flame propagates. [0198] 2) LFL, lower flammability limit: is the minimum concentration of a gas or vapour that is capable of propagating a flame within a homogenous mixture of that gas or vapour and air. [0199] 3) UFL, upper flammability limit: is the maximum concentration of a gas or vapour that is capable of propagating a flame within a homogenous mixture of that gas or vapour and air. [0200] 4) MIE, minimum ignition energy: indicates how much energy must be in an ignition source (e.g. spark or naked flame) to initiate ignition of a gas or vapour. [0201] 5) HOC, heat of combustion: is the energy released as heat when a specific amount of a substance undergoes complete combustion under standard conditions.

[0202] A class 3 blowing agent, will have an LFL which is significantly lower and a BV which is significantly higher than those of a class 2L blowing agent. The use of HCFOs and HFOs as blowing agents in phenolic foam should therefore facilitate the manufacture of insulation products having excellent fire performance. The present inventors have found that surprisingly this is not the case.

[0203] The present inventors prepared and investigated the fire performance and thermal conductivity of various blowing agents in phenolic foam with red phosphorus pre-dispersed in the foamable phenolic resin mix and found particular blowing agents which may be used to form thermal insulating phenolic foam having surprisingly excellent thermal conductivity values and fire performance. This effect is observed is for various blowing agents as described herein and in particular in relation to ternary blends of blowing agents described herein.

Resin Preparations

Resin A Preparation

[0204] To a reaction vessel was added on a weight basis (pbw=parts by weight) 50.0 pbw phenol, 1 to 4 pbw water and 0.9±0.2 pbw of 50% potassium hydroxide at 20° C. The temperature was raised to 70 to 76° C. and 35±2 pbw of 91% paraformaldehyde was added slowly over 1 to 3 hours to dissipate the heat of the reaction exotherm. The temperature was then raised to, and maintained in the range of from 82 to 85° C. until the viscosity of the resin reached 7,500 mPa.Math.s+/−1500 mPa.Math.s. Cooling was commenced whilst adding 0.3 pbw of 90% formic acid to neutralize pH. When the temperature has reduced to below 60° C., the following items were sequentially added: 2 to 6 pbw polyester polyol plasticiser, and 3 to 6 pbw of urea. When urea has dissolved then 2 to 5 pbw of ethoxylated castor oil (surfactant) are mixed in at 30 to 40° C. The resulting phenolic resin composition Resin A contained 10 to 13 wt. % water, less than 4 wt. % free phenol, and less than 1 wt. % free formaldehyde.

Resin P Preparation

[0205] To a reaction vessel was added on a weight basis (pbw=parts by weight) 50.0 pbw phenol, 1 to 4 pbw water and 0.9±0.2 pbw of 50% potassium hydroxide at 20° C. The temperature was raised to 70 to 76° C. and 35±2 pbw of 91% paraformaldehyde was added slowly over 1 to 3 hours to dissipate the heat of the reaction exotherm. The temperature was then raised to, and maintained in the range of from 82 to 85° C. until the viscosity of the resin reached 7,500 mPa.Math.s+/−1500 mPa.Math.s. Cooling was commenced whilst adding 0.3 pbw of 90% formic acid to neutralize pH. When the temperature reached 70+/−3° C., water was vacuum distilled to give a water content of 7.9 to 8.4% as measured by Karl Fisher analysis. When the temperature is below 60° C., the following items were sequentially added: 2 to 6 pbw polyester polyol plasticiser, and 3 to 6 pbw of urea. When urea has dissolved then add 7.6+/−1.5 parts of 50%+/−2% aqueous solution of red phosphorus and mix until uniformly dispersed. Then 2 to 5 pbw of ethoxylated castor oil (surfactant) are mixed in at 30° C. to 40° C. The resulting phenolic resin composition, Resin P, has 10 to 13 wt. % water content, less than 4 wt. % free phenol, and less than 1 wt. % free formaldehyde.

[0206] Phenolic Foam Preparation

[0207] A general procedure for the manufacture of phenolic foam boards is described in Comparative Example (CE) 1 below

COMPARATIVE EXAMPLE 1 (CE 1)

Blowing Agent (BA) is Isopropyl Chloride:Isopentane (iPC:iP 80+/−5:20+/−5 by weight)

[0208] To 110+/−5 pbw of Resin A at 15° C. to 19° C. was added with mixing at 300+/−100 rpm 5+/−2 pbw of calcium carbonate powder until calcium carbonate is uniformly dispersed. The said blended resin mix is pumped to a high speed mixer where 9+/−3 pbw of iPC:iP blowing agent at 1 to 3° C. and 20+/−3 pbw of 2:1 weight ratio toluene sulfonic acid:xylene sulfonic acid catalyst at 8 to 15° C. is quickly mixed into the resin blend. High speed mixing at 1000 to 4000 rpm is used to achieve intimate mixing so that a foamable composition is produced. Then said foaming resin composition was discharged to a suitable facing such as non-woven glass mat at a predetermined foamable resin flow rate to give the desired final foam cured density, such as 35 kg/m.sup.3, at the desired foam thickness such as 20 to 150 mm. Then the foamable mixture is carried by a moving horizontal conveyor belt into a conventional slat-type double conveyor foam lamination machine. The oven may have a uniform temperature such as 70° C. or may include several different temperature zones. Just before entering the foam lamination machine, a top facing is then introduced on to the foaming resin composition. The moving foam material passes through the heated oven press where the rising foam is pressurised at 40 to 50 kPa at a fixed gap to give the required foam board thickness. The foam expansion and initial curing in the oven press is for between 4 and 15 minutes. The partially cured foam that exits from the lamination machine is cut to a required length. The foam board is then placed in a secondary oven at 70° C. to 90° C. until fully cured. Table 4 gives details of a foam board manufactured using such a method.

COMPARATIVE EXAMPLE 6 (CE 6)

Blowing Agent (BA) is Isopropyl Chloride:Isopentane (iPC:iP 80+/−5:20+/−5 by Weight) Containing Half the Amount of Red Phosphorus that was Used in Resin P in Examples Ex1 to Ex6 Identified as Resin “P/2)”

[0209]

TABLE-US-00005 TABLE 4 CE 1 CE 6 IPC:IP (80:20) IPC:IP (80:20) Phenolic Resin “A” 111 0 Phenolic Resin “P/2” 0 111 Acid Catalyst 21 21 isopropyl chloride 7.6 6.8 isopentane 1.9 1.7 Sample thickness (mm) 84 100 Initial lambda (W/m .Math. K) 0.0182 110° C. aged 2 weeks lambda 0.0189 (W/m .Math. K) Foam density Kg/m.sup.3 35.8 Foam stable water content % 3.7 Compressive strength at first 120 crack (kPa) FIGRA 0.2 MJ (W/s) 232 132 FIGRA 0.4 MJ (W/s) 128 THR t = 600 s (MJ) 4.4 3.1 SMOGRA (m.sup.2/s.sup.2) 1 10.1 TSP t = 600 s (m.sup.2) 40 71 EuroClass Cs2d0 Cs2d0

COMPARATIVE EXAMPLE 2 (CE2)

Blowing Agent is HCFO-1233zd (E)

[0210] Here the same procedure as was used as outlined in Comparative Example 1 except the blowing agent was changed to 14.8 parts by weight of HCFO-1233zd (E) blowing agent at 1 to 3° C. The foam board produced had a density of 35.6 kg/m.sup.3.

COMPARATIVE EXAMPLE 3 (CE3)

Blowing Agent is HCFO-1233zd(E):IP (70:30)

[0211] Same as CE2 except the blowing agent is 8.47 pbw of HCFO-1233zd(E) and 3.63 pbw of isopentane.

COMPARATIVE EXAMPLE 4 (CE4)

Blowing Agent is HCFO-1233zd(E):HFO-1336mzz (Z) (95:5)

[0212] Same as CE2 except that the blowing agent is 13.18 pbw HCFO-1233zd(E) and 0.76 pbw HFO-1336mzz (Z).

COMPARATIVE EXAMPLE 5 (CE5)

Blowing Agent is HCFO-1233zd (E):HFO-1336mzz (Z):Isopentane (65:5:30)

[0213] Same as CE2 except that the blowing agent is 7.5 pbw of HCFO-1233zd(E), 0.58 pbw of HFO-1366mzz (Z) and 3.47 pbw of isopentane.

TABLE-US-00006 TABLE 5 CE3 CE4 CE5 CE2 HCFO: HCFO: HCFO: HCFO HC HFO HFO:HC (100) (70:30) (95:5) (65:5:30) Phenolic Resin A (pbw) 111 111 111 111 Acid Catalyst (pbw) 21 21 21 21 HCFO-1233zd E (pbw) 14.8 8.47 14.4 7.5 HFO-1366mzz (pbw) 0 0 0.76 0.58 isopentane (pbw) 0 3.63 0 3.47 Sample thickness (mm) 84 84 84 84 Initial lambda (W/m .Math. K) 0.0160 0.0176 0.0159 0.0177 110° C. aged 2 weeks 0.0168 0.0189 0.0166 0.0187 lambda (W/m .Math. K) Foam density Kg/m.sup.3 36.6 36.2 36.5 35.9 Foam stable water 3.8 3.7 4.1 4.2 content % Compressive strength 112 135 119 135 first crack (kPa) FIGRA 0.2 MJ (W/s) 394 237 272 157 FIGRA 0.4 MJ (W/s) 394 237 272 85 THR t = 600 s (MJ) 15.64 16.06 17.72 4.65 SMOGRA (m.sup.2/s.sup.2) 30.3 16.3 19.9 4.1 TSP t = 600 s (m.sup.2) 112 88 114 55 EuroClass Ds2d0 Cs2d0 Ds2d0 Cs2d0

EXAMPLE 1 (EX1)

Blowing Agent is HCFO-1233zd (E) IP (95:5) by Weight

[0214] Same as CE2 except that the resin used was Resin P and the blowing agent was 13.8 parts of HCFO-1233zd (E), and 0.73 parts of isopentane.

EXAMPLE 2 (EX2)

Blowing Agent is HCFO-1233zd (E):IP (95:5) by Weight

[0215] Same as Ex1 to assess the reproducibility of the SBI fire testing. So the blowing agent was 13.8 pbw of HCFO-1233zd (E), and 0.73 pbw of isopentane.

EXAMPLE 3 (EX3)

Blowing Agent is Isopropyl Chloride, iPC:IP (80:20) by Weight

[0216] Same as Ex 1 except that the blowing agent was 6.8 pbw of isopropyl chloride) and 1.7 pbw of isopentane.

EXAMPLE 4 (EX4)

Blowing Agent is Isopropyl Chloride, iPC:IP (80:20) by Weight

[0217] Same as Ex 1 except that the blowing agent was 6.8 pbw of isopropyl chloride) and 1.7 pbw of isopentane.

EXAMPLE 5 (EX 5)

Blowing Agent is Isopropyl Chloride, iPC:IP (80:20) by Weight

[0218] Same as Ex 1 except that the blowing agent was 6.8 pbw of isopropyl chloride) and 1.7 pbw of isopentane.

EXAMPLE 6 (EX 6)

Blowing Agent is Isopropyl Chloride, iPC:IP (80:20) by Weight

[0219] Same as Ex 1 except that the blowing agent was 7.9 pbw of isopropyl chloride) and 2.0 pbw of isopentane.

TABLE-US-00007 TABLE 6 Ex1 Ex2 HCFO1233zd: HCFO1233zd: Ex3 Ex4 Ex5 Ex6 iP iP iPC:iP iPC:iP iPC:iP iPC:iP (95:5) (95:5) (80:20) (80:20) (80:20) (80:20) Phenolic Resin “P” (pbw) 111 111 111 111 111 111 Acid Catalyst (pbw) 21.7 21.7 21.5 21.5 21.5 21.5 HCFO-1233zd E (pbw) 13.8 13.8 0 0 0 0 IPC (isopropyl chloride) 0 0 6.8 6.8 6.8 7.9 (pbw) HC (isopentane) (pbw) 0.73 0.73 1.7 1.7 1.7 2.0 Sample thickness (mm) 100 100 100 100 100 40 Initial lambda (W/m .Math. K) 0.0165 0.0162 0.0184 0.0179 0.0181 0.0181 110° C. aged 2 weeks 0.0176 0.0173 0.0197 0.0198 0.0196 0.0197 lambda (W/m .Math. K) Foam density Kg/m.sup.3 36.5 36.5 41.4 36.6 37.4 Foam stable water 4.2 4.2 content % Compressive strength 112 112 124 113 109 first crack (kPa) FIGRA 0.2 MJ (W/s) 68.3 68.0 52.2 83.3 85.0 84.6 FIGRA 0.4 MJ (W/s) 30.6 35.3 26.6 39.8 46.1 56.1 THR t = 600 s (MJ) 2.14 2.04 2.07 2.40 2.47 2.83 SMOGRA (m.sup.2 + s.sup.2) 13.4 12.00 9.27 4.46 3.64 9.08 TSP t = 600 s (m.sup.2) 98.8 93.8 81.4 55.8 52.9 87.5 EuroClass Bs2d0 Bs2d0 Bs2d0 Bs2d0 Bs2d0 Bs2d0

Discussion of Comparative Examples and Examples

[0220] The physical properties and fire performance of the foams in the comparative examples and examples are illustrated in Tables 4, 5 and 6.

[0221] The blowing agent in CE1 is a blend of isopropyl chloride and isopentane, in an 80:20 weight ratio blend by weight. CE1 exhibits desirable initial and aged thermal conductivity values, and the fire performance classifies the foam of CE1 as a Euroclass C product. CE6 is the same chemical composition as CE1 except that half the weight of red phosphorus has been introduced into the foamable phenolic resin compared to Ex 1 to Ex6 inclusive. This results in half the weight of red phosphorus in the cured foam. In the cured foam there is a substantial reduction in the FIGRA 0.2 MJ value, though not enough to achieve a Euroclass B fire rating.

[0222] The blowing agent in CE2 is entirely HCFO-1233zd (a non-flammable class 1 blowing agent in accordance with ISO817). The initial and aged thermal conductivity of CE2 are excellent, however, the fire performance results of CE2 are inferior to values expected for when a non-flammable blowing agent is used. High FIGRA 0.2 MJ and FIGRA 0.4 MJ values were observed when a foam board of CE2 was assessed in BS EN 13823. Accordingly, despite the use of a non-flammable blowing agent, the fire performance of CE2 is worse than that of CE1 which comprises flammable isopentane and flammable isopropyl chloride. CE2 is classified as a Euroclass D fire growth rate product with Class “C2” smoke emissions and “d0” no dripping observed.

[0223] CE3 comprises a blowing agent blend of HCFO-1233zd and isopentane, and exhibits desirable performance for initial and aged thermal conductivity values, and an improvement in fire performance in comparison to CE2. However, despite this improvement CE3 is classified as a Euroclass C product rather than Euroclass B.

[0224] CE4 comprises a blowing agent blend of HCFO-1233zd and HFO-1336mzz. HFO-1336mzz is also classified as a non-flammable Class 1 blowing agent in accordance with ISO 817. The initial and aged thermal conductivity values of CE4 are excellent. Despite having 2 non-flammable blowing agents, the FIGRA 0.2 MJ and FIGRA 0.4 MJ values are surprisingly greater than those observed for CE3 that contains flammable isopentane.

[0225] CE5 comprises a ternary blowing agent blend of HCFO-1233zd, HFO-1336mzz and isopentane. Despite the inclusion of highly flammable isopentane, the desired low initial and low aged thermal conductivity values remain almost constant but significantly, there is a dramatic improvement in the fire performance, albeit the FIGRA 0.2 MJ value remains above 150 W/s. (Euroclass C)

[0226] In contrast, Examples E1 to E6 demonstrate that a FIGRA 0.2 MJ value of less than 150 W/s can be achieved when a specific ternary blend of a chlorinated hydrofluoroolefin, a hydrofluoroolefin and a hydrocarbon is employed in the phenolic foamable chemical blend along with 2 to 5 parts by weight of micronized, (0.5 to 10 μm particle size), red phosphorus based on 100 parts by weight of cured phenolic foam which results in foam insulation products having excellent fire resistance properties, and low smoke emissions defined by FIGRA (0.2 MJ threshold)<150 W/s and SMOGRA<20 m.sup.2/s.sup.2. Indeed, each of Examples E1 to E6 demonstrate a FIGRA 0.2 MJ value of less than 120 W/s, and so are classified as having a desirable Euroclass B fire performance rating. This is achieved without deleteriously impacting the low thermal conductivity of the foam. The invention concerns stable insulation performance (<0.023 W/m.K), and a high closed foam cell content, (>85%).

[0227] The blowing agent used to form the phenolic foams of the invention may comprise at least one chlorinated hydrofluoroolefin, or at least one hydrofluoroolefin or at least one alkyl halide or at least one chlorinated alkene present and at least one C.sub.3-C.sub.6 hydrocarbon and combinations thereof. The at least one chlorinated hydrofluoroolefin or at least one alkyl halide or at least one chlorinated alkene or combinations thereof is desirably present in an amount of from about 62 wt. % to 95 wt. % based on the total weight of the blowing agent. The hydrofluoroolefin is desirably present in an amount of from about 5 to 15 wt. % based on the total weight of the blowing agent. The at least one C.sub.3-C.sub.6 hydrocarbon is desirably present in an amount of from 4 to 25 wt. % based on the total weight of the blowing agent.

[0228] As evidenced by comparing CE1 without red phosphorus in the foam, to CE6, which has half the optimum amount as is present in “Resin P”, there is a substantial improvement in the FIGRA 0.2 MJ value obtained for CE6 despite the presence of highly flammable isopropyl chloride and isopentane being present in the phenolic foam. However, with this reduced amount of red phosphorus present in the foam only Euroclass C is achieved. To achieve Euroclass B, the red phosphorus weight amount in foam needs to be in the range used in Examples 1 to 6 derived from “Resin P”. If excessive amounts of red phosphorus are added, beyond 5 parts by weight of red phosphorus in 100 parts by weight of cured foam, then the SMOGRA values will increase and there is a risk that low stable thermal conductivity will be compromised with time. The proposed range for the amount of red phosphorus, 2 to 5 parts with particle size 0.5 to 10 μm to be present in 100 parts by weight of cured phenolic foam and the particle size ensures the requirement for stable thermal conductivity and improved fire resistance. If too much red phosphorus is added to the foamable resin mix, then there are possible foam manufacturing issues when mixing due to the excessive high chemical blend viscosity. Historically improved foam fire resistance has been achieved by the presence of organic or inorganic phosphorus compounds in the foam. The concentration of phosphorus per unit weight is higher in red phosphorus that in other organic or inorganic phosphorus containing compounds. To obtain 2 to 5 parts by weight of phosphorus per 100 parts of cured phenolic foam would require much higher loadings of these other phosphorus compounds. Such higher additions would plasticise foam cells if the organophosphorus compound was a liquid or could damage foam cells during the mechanical foam mixing process if the organophosphorus compound is a solid. The adverse effect on the insulation foam is undesirable higher thermal conductivity

[0229] For example, ammonium polyphosphate particles at 5 parts/100 parts of uncured phenolic resin raises initial and aged foam lambda. Table 7 below shows the unit weight of elemental phosphorus is higher than other phosphorus based compounds permitting less flame retardant to be needed in the cured foam and so thermal conductivity is not compromised.

TABLE-US-00008 TABLE 7 % Elemental Physical Molecular Chemical Name Chemical Structure Phosphorus Form Weight 50% Aqueous Red P 50.0 Dispersion 31 Phosphorus Diphenyl Phosphine (C6H5)2—PH 16.6 Liquid 186.2 Diphenyl Phosphine Oxide (C6H5)2—P(H)═O 15.3 Solid 202.2 Diphenyl Phosphate (C6H5O)2—P(OH)═O 12.4 Solid 250.2 Diphenyl Phosphite (C6H5O)2—P(H)═O 13.3 Liquid 234 Diethyl Phosphite (C2H5O)2—P(H)═O 22.4 Liquid 138.1 Triphenyl Phosphine (C6H5)3—P 11.8 Solid 262.3 Triphenyl Phosphine Oxide (C6H5)3—P═O 11.1 Solid 278.3 Triphenyl Phosphate (C6H5O)3—P═O 9.5 Solid 326.3 Triphenyl Phosphite (C6H5O)3—P 10 Liquid 310 Triethyl Phosphine oxide (C2H5)3—P═O 23.1 Solid 134.2 Triethyl Phosphate (TEP) (C2H5O)3—P═O 17.0 Liquid 182.2 Triethyl Phosphite (C2H5O)3—P 18.6 Liquid 166.2 Diethyl ethyl phosphonate (C2H5O)2—P═O 15.3 Liquid 202 DEEP | C2H5 Tris (2-chloropropyl) (Cl—CH2CH—O)3— 9.5 Liquid 327.6 phosphate P(CH3)═O TCPP TMCP 9.4 Liquid Chlorinated phosphate ester Ammonium Polyphosphate —(NH4PO3)n- 31.5 Solid n > 1000 Ammonium Phosphate NH4H2PO4 26.9 Solid 115

[0230] Typically 2 to 5 parts by weight of red phosphorus per 100 parts by weight of cured phenolic foam are needed to obtain Euroclass Class B foam insulation products with an appropriate blowing agent blend and surfactant type.

[0231] However, if the amount of hydrocarbon exceeds about 25 wt. % of the blowing agent composition, the fire performance of the foam could be negatively impacted, and the attainment of a Euroclass B foam is not possible. Furthermore, as evidenced by CE2 and CE4, if less than about 5 wt. % hydrocarbon is present, the fire performance is also deleteriously impacted.

[0232] If less than about 3 wt. % hydrofluoroolefin is present, the fire performance of the product declines, and if greater than about 20 wt. % hydrofluoroolefin is present, the thermal conductivity of the foam product increases.

[0233] Accordingly, optimal thermal insulation performance and fire performance is achieved, when the blowing agent comprises the aforementioned ternary blend.

[0234] In the foams of the invention the % friability is below 30% for example below 25% as measured according to test method ASTM C421-08(2014).

[0235] A further desirable aspect of the invention is that the presence of 2 to 5% by weight of micronized (for example 0.5 to 10 μm particle size) red phosphorus flame retardant present in 100 parts by weight of cured phenolic foam results in phenolic foam insulation products having reduced formaldehyde emissions from phenolic foam articles by 30 to 60% as measured by EN717-1/EN16516/ISO16000-11. Table 8 below shows the formaldehyde scavenging effect of red phosphorus present in phenolic foam regardless of blowing agent type.

TABLE-US-00009 TABLE 8 Test Loading Formaldehyde Phenolic Blowing Chamber Factor Emission Sample Details Resin Agents Size (m.sup.2/m.sup.3) (μg/m.sup.3) 100 mm Phenolic Resin 80:20 by 1 m.sup.3 1.0 98 Foam Board with “P” weight 25 μm perforated foil- iPC:iP glass mat facings 80 mm Phenolic Foam Resin 80:20 by 1 m.sup.3 1.0 200 Board with 25 μm “A” weight perforated foil-glass iPC:iP mat facings 110 mm Phenolic Resin 80:20 by 1 m.sup.3 1.0 170 Foam Board with “A” weight 25 μm perforated foil- iPC:iP glass mat facings 100 mm Phenolic Resin HCFO1233zd: 1 m.sup.3 1.0 24 Foam Board with “P” iP 25 μm perforated foil- (85:15) glass mat facings 90 mm Phenolic Foam Resin HCFO1233zd: 1 m.sup.3 1.0 160 Board with 25 μm “A” iP perforated foil glass (85:15) mat facings

[0236] As outlined above, the at least one chlorinated hydrofluoroolefin is present in an amount of from about 65 wt. % to about 92 wt. % based on the total weight of the blowing agent used to form the phenolic foam of the present invention. Preferably, the chlorinated hydrofluoroolefin is present in an amount of from about 72 wt. % to about 92 wt. % based on the total weight of the blowing agent. More preferably, the chlorinated hydrofluoroolefin is present in an amount of from about 72 wt. % to about 88 wt. % based on the total weight of the blowing agent, even more preferably the chlorinated hydrofluoroolefin is present in an amount from about 72 wt. % to about 82 wt. % based on the total weight of the blowing agent.

[0237] The at least one hydrofluoroolefin is present in an amount of from about 5 wt. % to about 20 wt. % based on the total weight of the blowing agent used to form the phenolic foam of the present invention. Preferably, the hydrofluoroolefin is present in an amount of from about 5 wt. % to about 15 wt. %, such as from about 8 wt. % to about 14 wt. % based on the total weight of the blowing agent.

[0238] The C.sub.3-C.sub.6 hydrocarbon is present in an amount of from about 4 wt. % to about 25 wt. % based on the total weight of the blowing agent used to form the phenolic foam of the present invention. Preferably, the C.sub.3-C.sub.6 hydrocarbon is present in an amount of from about 5 wt. % to about 20 wt. %, such as from about 8 wt. % to about 18 wt. % based on the total weight of the blowing agent.

[0239] Suitably, the chlorinated hydrofluoroolefin is selected from HCFO-1233zd and HCFO-1224yd.

[0240] The chlorinated hydrofluoroolefin may be HCFO-1233zd-(E) and/or HCFO-1233zd-(Z). For example, the 1233zd may be at least 90 wt. % of the E-isomer (HCFO-1233zd-(E)), such as at least 95 wt. % of the E-isomer (HCFO-1233zd-(E)).

[0241] The hydrofluoroolefin is suitably HFO-1336mzz. The HFO-1336mzz may be HFO-1336mzz-(Z) and/or HFO-1336mzz-(E). For example, the HFO-1336mzz may be at least 90 wt. % of the Z-isomer (HFO-1336mzz-(Z)), such as at least 95 wt. % of the Z-isomer (HFO-1336mzz-(Z)).

[0242] Suitably, the C.sub.3-C.sub.6 hydrocarbon is a propane, butane, pentane, hexane or isomer thereof. More suitably, the C.sub.3-C.sub.6 hydrocarbon comprises a butane and/or a pentane. Preferably, the butane comprises isobutane. Preferably, the pentane comprises isopentane.

[0243] Advantageously, each of the foams of Examples 1 to 6 demonstrate stable low thermal conductivity over extended time and temperature exposure, and excellent fire performance. Each of the foams of examples 1 to 6 are Euroclass B products.

[0244] 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.

[0245] 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.