COMPOSITIONS FOR PRODUCING FOAMED MATERIALS

Abstract

The invention relates to a composition for the production of foams based on phenolic resin, use thereof, and a process for the production of the composition. For provision of a composition for the production of foams based on phenolic resin, where the said composition delivers improved reaction to fire with, in essence, no alteration of further important foam properties, it is proposed that the composition comprises an alkoxylated novolak, wherein the novolak is produced using phenol, cresol and/or xylenol.

Claims

1. A composition for the production of foams based on phenolic resin comprising an alkoxylated novolak, wherein the novolak is produced using phenol, cresol, xylenol, and combinations thereof.

2. The composition of claim 1, wherein the degree of alkoxylation of the alkoxylated novolak comprises from 5 to 100%.

3. The composition of claim 1, wherein the alkoxylated novolak comprises an ethoxylated novolak, a propoxylated novolak, or both.

4. The composition of claim 3, wherein the alkoxylated novolak comprises a binary mixture of ethoxylated novolak and propoxylated novolak.

5. The composition of claim 1, wherein the alkoxylated novolak comprises a co-condensate obtained from reaction of at least two different alkoxylating agents with at least one novolak.

6. The composition of claim 1, wherein the novolak comprises a polyalkoxylated novolak.

7. The composition of claim 1, wherein the alkoxylated novolak comprises from 5 to 50% by weight based on the weight of the condensate used of a phenolic compound and formaldehyde.

8. The composition of claim 1, further comprising components selected from the group consisting of additives, surfactants, emulsifiers, plastifying agents, solvents, hardeners, blowing agents, and combinations thereof.

9. The process of claim 10, wherein the alkoxylated novolak is used in a form dissolved in a solvent or solvent mixture.

10. A process for the production of a composition for the production of foams according to claim 1, based on phenolic resin, comprising at least the following steps: a) producing a condensate via condensation of at least one phenolic compound and formaldehyde in a molar ratio of from 1:1.0 to 1:3.0 with the aid of a basic catalyst and optionally addition of further added substances, b) distilling the condensate produced in a), c) adding an alkoxylated novolak and addition of, and optionally further added substances before and/or after distillation.

11. A process for the production of a composition for the production of foams according to claim 1, based on phenolic resin, comprising at least the following step: producing a condensate made of at least one phenolic compound, and formaldehyde, and of an alkoxylated novolak with the aid of a basic catalyst and optionally addition of further added substances, where the phenolic compound and formaldehyde are present in a molar ratio of from 1:1.0 to 1:3.0.

12. The process of claim 11, wherein the alkoxylated novolak is used in a form dissolved in a solvent or solvent mixture.

13. The process of claim 9, wherein the solvent or solvent mixture comprises triethyl phosphate, diethylene glycol, or both.

14. The process of claim 12, wherein the solvent or solvent mixture comprises triethyl phosphate, diethylene glycol, or both.

Description

[0042] The invention will be explained in more detail with reference to an embodiment: [0043] a.) Production of the ethoxylated novolak [0044] 1. 126.21 g of phenol are charged as solid into a reactor and melted at temperatures of from 55 to 60° c. [0045] 2. 0.374 g of oxalic acid dihydrate and 0.374 g of water are then added, with stirring, and the reaction mixture is heated to from 100° c. to 110° c. 32.257 g of 45% formalin are then added over a period of 1 h at from 100° C. to 110° C., whereupon reaction continued for 3 h at reflux. The novolak was distilled in order to reduce free phenol content (<0.1%) and water content. [0046] 3. For the ethoxylation of the resultant novolak, 0.174 g of potassium carbonate was directly added at from 170 to 180° C. into the resin, and mixed into the material. 58.714 g of ethylene carbonate are fed into the mixture over a period of 5 h at from 175 to 180° C. Carbon dioxide is liberated. The feed time can optionally be increased as far as 8 h, in accordance with the technical capability of discharging carbon dioxide. [0047] 4. For the continued reaction, the temperature is maintained at from 175° C. to 180° C. for 1 h, or else optionally for longer, until no further carbon dioxide is produced and the reaction has been concluded. [0048] 5. The reaction mixture is cooled to 150° C., and 0.347 g of salicylic acid is added. [0049] 6. Once the product has been further cooled (100° C.), it can be drawn off.

[0050] Data for the ethoxylated novolak:

[0051] Melting range: 25+/−IO OC

[0052] Cone-on-plate viscosity at 1000 C: 300±200 mPa*s

[0053] Water content by Karl Fischer method: max. 0.30%

[0054] Molar mass (Mn) by vapor pressure osmometry.: 485 f 50 g/mol

[0055] Degree of alkoxylation (GC-MS, sil): >95% [0056] b.) Production of a polyethoxylated novolak [0057] 1000 g of a novolak with a Mn of 270 g/mol was melted at 95° C., and 4.2 g of a 100% KOH solution, and 8.4 g of water, were added. The water was removed by distillation in vacuum at from 100 to 120° C. [0058] In a temperature range from 140° C. to 150° C., taking account of the exothermicity, 2181 g of ethylene oxide (5 mol) were slowly added, and for the continued reaction the temperature was maintained at from 150° C. to 160° C. The resultant product was cooled to 800 C and neutralized with 6.7 g of lactic acid.

[0059] Data for the polyethoxylated novolak:

[0060] Viscosity at 25° C.: 2240 mPa*s

[0061] Water content: max. 0.24%

[0062] Density at 20° C.: 1.16 g/ml [0063] c) Production of the phenol-formaldehyde condensate/alkoxylated novolak (foam resin) composition

[0064] The foam resin was produced by mixing, in a laboratory reactor with stirrer, 100 g of phenol with 108.5 g of formaldehyde (45% aqueous solution) and 3.6 g of KOH (5 0% aqueous solution). This solution is heated to 960 C, with stirring. The reaction mixture was cooled to 45° C. in the reaction vessel, and an appropriate quantity of non-alkoxylated novolak (Comparative Examples in Table 1) and of alkoxylated novolak (inventive embodiments in Tables 2 to 4) was admixed, and the mixture was homogenized with stirring. The percentage of non-alkoxylated novolak and alkoxylated novolak refers to the weight of the phenolformaldehyde-condensate (foam resin). Water was then removed by distillation under reduced pressure. [0065] d) Production of the foam

[0066] The following were added in succession, with stirring, to 354.4 g of the foam resin produced in c): 15.1 g of ethoxylated castor oil and 29.6 g of a blowing agent mixture consisting of 85% by weight of isopentane and 15% by weight of cyclopentane. Finally, 48.0 g of hardener consisting of 80% by weight of phenolsulfonic acid and 20% by weight of phosphoric acid (75%) were stirred into the mixture.

[0067] The reaction mixture was immediately transferred into a wooden mould preheated to 60° C., securely closed by a screw-threaded wooden lid. The mould was placed into an oven controlled to a temperature of 60° C. After one hour, the foaming process had concluded, and the foam could be demoulded. The foam was then post-cured at 600 C in the oven for 24 hours.

[0068] Friability was calculated by determining the loss of mass from a premoulded foam cube (edge length 25 mm), placed in a wooden cube (edge length 200 mm) with lid rotating at a speed of 60 rpm (12 determinations).

[0069] Closed cell content was measured in accordance with “EN ISO 4590—Rigid cellular plastics—Determination of the volume percentage of open cells and of closed cells”, and the lambda values (X-value) were determined in accordance with ISO 8301—“Thermal insulation—Determination of steady-state thermal resistance and related properties—Heat flow meter apparatus”.

[0070] Reaction to fire was assessed by measuring the spall rate and the flame resistance by holding the flame of a Bunsen burner at a distance of 10 cm from a sample of which the weight had previously been determined. After at most 5 min, the flame was removed and the weight of the spalled material was again determined. The percentage weight difference is the spall rate. If the flame penetrated the entire material before expiry of the time of 5 min, the relevant time has been stated (flame resistance) and the quantity of spalled material before that juncture has been used to calculate the spall rate. Longer time it takes for the flame to travel through the sample (improved flame resistance) and lower spall rate are measures of improved reaction to fire (fire performance). All samples were self-extinguishing and generated no smoke.

TABLE-US-00001 TABLE 1 Non-alkoxylated novolak Without Quantity [g]/[%] novolak 11.9/7.2 25.1/13.8 39.8/20.9 Properties (I) (Il) (Ill) (IV) Foam resin Water content [%] 17.0 18.1 15.5 16.7 Free HCHO 0.6 0.5 0.5 0.5 content [%] Free phenol 6.3 5.5 5.7 4.9 content [%] Viscosity at 2560 2600 3200 2640 25° C. [mPa*s] Foam Density [kg/m.sup.3] 33.6 34.5 34.0 32.1 Closed-cell 96.6 95.9 95.8 89.8 content [%] Friability [%] 34.8 32.1 31.6 23.5 Λ-value 24.1 29.6 35.8 35.8 [mW/m*K] Spall rate [%] 12.0 10.3 1.3 0.15 Flame resistance 2:47 min 2:13 min 3:54 min 5:00 min

TABLE-US-00002 TABLE 2 Degree of ethoxylation of ethoxylated novolak 100% 80% Quantity [g]/[%] Quantity [g]/[%] 11.9/6.9 25.1/13.0 39.8/18.7 11.9/6.6 25.1/12.8 39.8/19.0 Properties (V) (VI) (VIl) (VIll) (IX) (X) Foam resin Water content [%] 16.2 17.2 15.9 16.5 16.2 14.9 Free HCHO 0.6 0.5 0.5 0.6 0.6 0.5 content [%] Free phenol 5.3 5.1 4.8 5.4 4.8 4.5 content [%] Viscosity at 2720 2000 3040 2360 2880 4320 25° C. [mPa*s] Foam Density [kg/m.sup.3] 35.3 34.3 34.7 35.2 35.6 35.9 Closed cell content 94.1 92.7 93.2 94.1 91.8 94.5 Friability [%] 37.5 38.0 36.0 36.8 32.9 24.7 Λ-value 24.9 24.8 25.7 24.2 24.2 24.0 [mW/m*K] Spall rate [%] 9.2 2.2 <0.1 10.9 3.5 <0.1 Flame resistance 3:15 min 5:00 min 5:00 min 2:27 min 5:00 min 5:00 min

TABLE-US-00003 TABLE 3 Degree of ethoxylation of ethoxylated novolak 50% 30% Quantity [g]/[%] Quantity [g]/[%] 11.9/6.7 25.1/12.8 39.8/18.8 11.9/6.8 25.1/13.0 39.8/18.7 Properties (XI) (XII) (Xlll) (XIV) (XV) (XVI) Foam resin Water content [%] 16.6 16.3 16.0 16.8 15.9 17.0 Free HCHO 0.6 0.5 0.5 0.6 0.5 0.5 content [%] Free phenol 5.3 5.0 4.6 5.1 4.9 4.5 content [%] Viscosity at 3200 3520 3840 2520 3040 3520 25° C. [mPa*s] Foam Density [kg/m.sup.3] 37.6 39.3 36.2 37.2 38.2 36.0 Closed cell content 92.5 93.8 94.4 92.7 93.1 93.6 [%] Friability [%] 31.4 29.2 23.2 34.5 30.6 23.6 Λ- value 23.9 23.4 23.7 24.5 23.4 26.8 [mW/m*K] Spall rate [%] 7.0 0.5 <0.1 11.1 0.1 <0.1 Flame resistance 3:05 min 5:00 min 5:00 min 2:30 min 5:00 min 5:00 min

TABLE-US-00004 TABLE 4 Propoxylated novolak (degree of propoxylation 100%) Quantity [g]/[%] 39.8/18.7 Properties (XVII) Foam resin Water content [%] 15.7 Free HCHO 0.51 content [%] Free phenol 4.4 content [%] Viscosity at 6400 25° C. [mPa*s] Foam Density [kg/m.sup.3] 39.4 Closed cell content [%] 93.46 Friability [%] 37.5 Λ- value 24.1 [mW/m*K] Spall rate [%] <0.1 Flame resistance >5:00 min

[0071] Tables 1 through 4 illustrates the effect of introducing non-alkoxylated novolak and alkoxylated novolak at three different concentrations relative to the phenolic resole (without a novolak—sample (1)). The samples include both ethoxylated and propoxylated novolaks

[0072] (XVII), wherein ethoxylated novolaks with varying degree of ethoxylation from 100%, 80%, 50% and 30% were used. Each table lists the critical properties of the foam such as reaction to fire as indicated by spall rate and flame resistance (time it takes to penetrate), thermal conductivity (A-value) and friability.

[0073] Table 1 shows that addition of non-alkoxylated novolaks also improves reaction to fire compared to the sample (1) (without novolak). However, this is accompanied by increased thermal conductivity that indicates poor thermal resistance, which is undesirable. For example, increasing the concentration of the novolak from 7.2% (II) to 13.8% (III) further reduced the spall rate and increased flame resistance. However, the A-value increased significantly from 29.6 to 35.8 mW/m*K.

[0074] On the contrary, introduction of the alkoxylated novolaks (Tables 2, 3 and 4) resulted in significant improvements to reaction to fire as evidenced by reduction in spall rate and high flame resistance without decreasing the thermal insulation property. These results are somewhat unexpected because introduction of an aliphatic chain by alkoxylating is typically expected to reduce flame resistance. Even more unexpected result is the improvement to reaction to fire achieved through the incorporation of propoxylated novolak which contains an additional methyl group per alkoxylation unit compared to ethoxylated novolak. Another feature that distinguishes the alkoxylated novolaks from non-alkoxylated novolaks is the level of improvements to reaction to fire that can be achieved. The lowest reduction in spall rate achieved through the non-alkoxylated novolak was 0.15% (IV—at 20.9% non-alkoxylated novolak). Samples containing a similar proportion of alkoxylated novolacs (VII, X, XIII, XVI) had a spall rate of <0.1%. The use of alkoxylated novolaks in phenolic resin-based foams thus brings more significant improvements in fire performance than the use of non-alkoxylated novolaks.

[0075] In Tables 2 and 3, it has been proved according to the invention that use of alkoxylated novolaks with increasing proportion by weight in the phenolic resin (samples: (V) to (VII); (VIII) to (X); (Xl) to (Xlii); (XIV) to (XVI)) brought about improved reaction to fire with unchanged low thermal conductivity. This phenomenon was apparent even at a degree of alkoxylation as low as 30% (samples (XIV) to (XVI)).

[0076] Best results were achieved through the addition of ethoxylated novolak with a degree of ethoxylation of 50% at ca.19% concentration (XIII). This resulted in a foam that had the lowest spall rate of <0.1%, superior flame resistance of 5 minutes, lowest friability of 23.2% while retaining or improving the thermal insulation performance compared to the control foam (1). Thus, in comparison to the control foam (1), foam (XIII) exhibits >99% reduction in spall rate, 80% increase in flame resistance and a 33.3% improvement in friability.