JPH0549703B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a phenol foam that has excellent flame resistance, no corrosion of metals that come into contact with the foam, a high closed cell ratio, and excellent heat insulation performance. Conventionally, phenol foam has attracted attention as a non-combustible heat insulating material due to its superior flame resistance and non-combustibility compared to polystyrene-based thermoplastic resin foam or polyurethane-based rigid foam. It's here. However, the nonflammability of conventional phenol foams is not sufficient. For example, when evaluating nonflammability using the JISA1321 method, the foam cracks and deformation is large, and its performance as a quasi-noncombustible material is poor. does not have. In addition, since acid catalysts are used to cure the resin in the production of phenol foam, these acid catalysts are used in the foam, so these acid catalysts remain in the foam and when insulation is applied, metals that come into contact with the foam may be It also has the disadvantage of corrosion, and conventional phenol foam has a closed cell ratio of zero or at most 50.
The insulation performance was also poor. On the other hand, research has been conducted to improve these drawbacks of phenol forms, such as the US patent
No. 3298973 describes a method using a mixture of boric acid and an organic hydroxy acid compound as a catalyst;
No. 52168 discloses a method of adding a non-volatile amine compound, and JP-A-55-82133 discloses a method of adding an inorganic filler. However, even if flame resistance is improved by these methods, the insulation performance, which is an important property for insulation materials, is not improved.
In addition, the corrosion resistance to metals is the same as that of conventional products, and it has not yet been put into practical use. The present invention relates to a method for producing an excellent phenol foam that improves these drawbacks of phenol foam, has excellent flame resistance, has a closed cell ratio of 80% or more, has excellent heat insulation performance, and is free from corrosion of metals. That is, the present invention provides a method for producing a foam by mixing a resol type phenolic resin with an epoxy compound acid catalyst and a blowing agent, wherein the epoxy compound is a compound represented by the general formula [], (However, n is an integer of 1 or more) In the orthogonal coordinates consisting of the X axis defined by the amount of epoxy compound added and the Y axis defined by the amount of acid catalyst added, coordinate point A (0.060, 0.0475),
B (0.079, 0.0550), C (0.150, 0.070), D (0.060
，
0.0355) A method for producing phenol foam with excellent flame resistance, characterized by foaming a composition within the range surrounded by The amount of acid catalyst (Y) expressed in [ ] is mol/100g of phenolic resin. ] Y = Acid catalyst addition amount + 0.047 (1-R) ...Formula (where R is the reaction activity index of the resol type phenolic resin) It is a U.S. patent to add an epoxy compound to a phenolic resin to improve its physical properties. No. 3298973, Japanese Patent Publication No. 1983
Although it is also described in No. 82133, there are no examples of the epoxy compound used in the present invention, and even if the above-mentioned known technology is applied by changing only the epoxy compound, the object of the present invention cannot be achieved. The epoxy compound used in the present invention is represented by the general formula [], and examples thereof include glycerin diglycidyl ether, diglycerin diglycidyl ether, triglycerin diglycidyl ether, and mixtures thereof. The amount added is 0.060 to 0.150 mol per 100 grams of resol type phenolic resin, and if the amount is less than 0.060 mol, flame resistance, closed cell ratio, and heat insulation performance will not be improved, which is not preferable. Furthermore, if the amount is more than 0.150 mol, the cells in the resulting foam will become significantly larger and the closed cell ratio will also decrease, which is not preferable. Furthermore, the amount of epoxy compound added varies depending on the reaction activity of the resol type phenol resin used and the amount of catalyst added. ) in Cartesian coordinates (Fig. 1) with Y axis as coordinate point A
(0.060, 0.0475), B (0.079, 0.0550), C (0.150
，
0.070), D(0.060, 0.0355) is important. Acid catalyst amount (Y) = Acid catalyst addition amount + 0.047 (1-R) ... [Formula] [In the formula, acid catalyst addition amount; mol/100g Phenol resin R: Reaction activity index of resol type phenolic resin 100
Mix 20 g of a foaming agent (trichlorotrifluoroethane) and 9 g of p-toluenesulfonic acid with g resol type phenolic resin, foam and cure in an atmosphere of 60°C, and time (t minutes) until the foam solidifies (touch with finger). Find the value indicated by the dimension. ] R = 20/t Even if the amount added is within the range of 0.060 to 0.150 mol, if more epoxy compound is added than the amount determined by line segment CD in Figure 1, the curing of the resol type phenolic resin will be significant. This is not preferable because the foam may shrink after foaming or may not foam properly. Also, line segments AB and
If the amount is less than BC, the closed cell ratio will be significantly lowered, resulting in a substantially open cell foam, the insulation performance will not be improved, and the foam will be extremely corrosive to metals, which is unfavorable. The reason for using the value specified by the formula for the amount of acid catalyst used in the present invention is that unless the reactivity of the phenolic resin and the reactivity of the epoxy compound to be used are balanced, the excellent foam aimed at in the present invention will not be obtained. This is because they cannot be obtained. Conventionally, the higher the reactivity of the phenolic resin (the larger R), the less acid catalyst is required for its curing reaction, so even in the production of foams, compositions based on this stoichiometry have always been used. However, in the present invention, it was discovered that the viscoelasticity of the phenolic resin composition becomes suitable for foaming within the range of the amount of acid catalyst which has an inverse relationship to this, and the present invention has been completed. The reasons for the specific effects of the epoxy compound used in the present invention are not clear at present, but include its compatibility with resol type phenolic resin due to its specific chemical structure, reaction curing characteristics during the foaming process of the resin mixture, and resin viscosity at that time. , elastic properties, resin morphology properties, etc. are within the range suitable for foaming, suppressing damage to the cell membrane during foaming, achieving a closed cell ratio of 80% or more, and extremely reducing the amount of residual acid catalyst in the foam. In addition, a chemical structure is formed within the cured phenolic resin structure that reduces dimensional shrinkage when the foam burns and carbonizes, increases the mechanical strength of the generated carbide, and reduces the afterflame of the carbide. it is conceivable that. The resol type phenolic resin used in the present invention is a liquid phenolic resin obtained by a polycondensation reaction of phenol and formaldehyde, and is manufactured by a known manufacturing method. Liquid resol-type resins can be used as appropriate, but from the viewpoint of operability in manufacturing the foam, the viscosity at 25°C must be 200°C.
~300,000 centipoise and a water content of 10% by weight or less is preferred. As the acid catalyst used in the present invention, conventionally known acids such as organic carboxylic acids, organic sulfonic acids, and inorganic acids are used. For example, oxalic acid, formic acid, para-toluene sulfonic acid, xylene sulfonic acid, phenolic acid, phosphoric acid, boric acid, etc. are used, and para-toluene sulfonic acid and xylene sulfonic acid are particularly useful because of their high foaming rate and foam hardening rate. These acid catalysts can be used alone or in a mixture, but if they are mixed, the sum of the acid catalyst addition amounts (Y) in the formula [] calculated for each component acid is within the scope of the present invention. Use at various mixing ratios. The blowing agent used in the present invention is a volatile organic compound with a low boiling point. Preferably the boiling point is -40℃~
A 95° C. polyhalogenated saturated fluorocarbon, a halogenated hydrocarbon, a hydrocarbon, or a mixture thereof, and a halogenated fluorohydrocarbon is particularly preferred since it improves the heat insulation performance. Examples of blowing agents used are chloroform, methyl chloride, trichlorofluoromethane, methyl chloride, trichlorofluoroethane, tetrafluoromethane, 1,1,2-trichloro-1,
2,2-trifluoroethane, monochlorodifluoromethane, dichlorodifluoromethane, 1,1
-dichloro-1,2,2,2-tetrafluoroethane, 1,2-dichloro-1,1,2,2-tetrafluoroethane, 1,1,1-trichloro-
2,2,2-trifluoroethane, 1,2-difluoroethane, 1,1,1,2-tetrachloro-
2,2-difluoroethane or a mixture thereof. The phenol foam of the present invention can be produced by conventionally known methods, such as a method in which a resin composition, a blowing agent, and a curing catalyst are uniformly kneaded, injected into a mold, and foamed and cured; During foaming, glass fiber woven fabric is applied to the surface of the foam.
A method of manufacturing a composite panel by supplying reinforcing material such as kraft paper or metal-laminated kraft paper can be applied. The foam evaluation method used in the present invention will be described below. 1 Density Measured according to JIS A 9514. 2 Closed cell ratio Measured by the air pycnometer method described in ASTM D2856. 3 Non-flammability test Evaluation was made under test conditions equivalent to flame retardant class 2 as described in JIS A 1321 method. Evaluation Good: Passed as a second class flame retardant material. Poor: Cracks and deformation exceeding the allowable value occurred in the test sample. 4 Acid content of water extract Dry the foam sample at 70℃ until it reaches a constant weight, crush it, accurately weigh 1.0 g, and add 20 ml of distilled water.
Extract by shaking for 30 minutes at 25℃ and extract using Whatman
It was filtered through 1PS paper, and 5 ml of the solution was titrated with a 0.01N aqueous sodium hydroxide solution using a phenolphthalein indicator to determine the amount (mol) of acid remaining per gram of foam. 5 Corrosion test A blasted cold-rolled steel plate was sandwiched between form samples (length 100 x width 100 x thickness 20 mm), and 25
After being left in an atmosphere of 65% RH for one month, the test steel plate was taken out and the state of corrosion on its surface was observed and evaluated. Evaluation: Good... Rust is observed on the edges, but there is no change in the surface of the steel plate. Severe corrosion: Rust is observed on both sides of the steel plate. Example 1 15 grams of trichloromonofluoromethane and 0.06 mole of glycerin diglycidyl ether were added to 100 grams of liquid resol type phenolic resin (viscosity at 25° C. 5 poise, reactivity index R = 0.50), mixed uniformly, and para-toluene sulfone was added. Add 2.75 g of a 75% aqueous solution of acid and mix uniformly with a high-speed stirrer.
The mixture was poured into a square mold with sides of 200 mm and foamed. The foam was then left in a dryer at 70°C for 20 minutes to complete curing. (Experiment No. 1) The physical properties of the obtained foam were: density 40Kg/m ² , closed cell ratio 82%, thermal conductivity 0.0160 (0°C) Kcal/m・
At hr°C, it exhibited excellent flame resistance with an afterflame time of 20 (seconds), a smoke generation coefficient of 15, a temperature time area of 3 (°C minutes), and no cracking or deformation. Further, the amount of residual acid in the foam was 4 x 10 ^-5 mol/g, and corrosion evaluation using a steel plate brought into contact with the foam also showed good results. Example 2 Foaming was carried out in the same manner as in Example 1 except that the amount of glycerin diglycidyl ether and the amount of para-toluic acid aqueous solution added were changed to the amounts shown in Table 1. The physical properties of the obtained foam are shown in Table 1. (Experiment Nos. 2, 3 and 4) Comparative Examples 1 and 2 Foaming was carried out in the same manner as in Example 1 except that the amount of glycerin diglycidyl ether was changed to 0.05 mol. (Experiment No. 5) In addition, in Example 2, Experiment No. 2 and No. 4, the amount of glycerin diglycidyl ether was 0.05, respectively.
Foaming was carried out in the same manner except that the amount was changed to 0.16 mol and 0.16 mol. (Experiment Nos. 6 and 7) The physical properties of the obtained foams are shown in Table 1. The foam of Experiment No. 7 had a large cavity in the center, and the bubbles were large (5 mm or more) and irregular, giving it a poor appearance.

[Table] Example 3 Foaming was carried out in the same manner as in Example 1, except that the amounts of glycerin diglycidyl ether and paratoluene aqueous solution were changed to 0.06 mol and 5.5 g; 0.079 mol and 7.2 g, respectively. The results are shown in Table 2, Experiment Nos. 8 and 9. Example 4 20 grams of 1,1,2-trichloro-1,2,2-trifluoroethane per 100 grams of liquid resol type phenolic resin (viscosity at 25°C 300 poise, reactivity index R=1.0) 0.06 grams of 1,1,2-trichloro-1,2,2-trifluoroethane 9.76 g of a 75% aqueous solution of para-toluenesulfonic acid was added and mixed uniformly using a high-speed stirrer, and the mixture was poured into a square mold with sides of 200 mm and foamed. The foam was then left in a dryer at 70°C for 20 minutes to complete curing. (Experiment No. 10) The physical properties of the obtained foam were as shown in Table 2, No. 8. (Afterflame time 20 seconds, smoke coefficient 12 temperature time area 3℃, no cracks or deformation observed) Also, the amount of glycerin diglycidyl ether and the amount of paratoluenesulfonic acid aqueous solution added were 0.0795 mol and 11.5 mol, respectively. Foaming was carried out in the same manner except that the amount was changed to 0.10 mol and 13.5 grams. The physical properties of the obtained foam are shown in Table 2, Experiment Nos. 11 and 12. Comparative Example 3 Foaming was carried out in the same manner as in Example 1 except that the amounts of glycerin diglycidyl ether and para-toluene sulfonic acid aqueous solution were changed to those shown in Experiment Nos. 13, 14, 15, and 16 in Table 2. . In Experiments No. 13 and 15, the foam hardened slowly at 70°C.
Curing was completed by heating in a constant temperature room for 2 hours. Comparative Example 4 In Example 4, the amounts of glycerin diglycidyl ether and para-toluene sulfonic acid aqueous solution were changed to those shown in Experiment Nos. 17 and 18 in Table 2.
Foaming was carried out in the same manner. In Experiment No. 17, the foam hardened slowly and was completed by heating in a constant temperature room at 70°C for 1 hour.

[Table] Experiment No. 9 in Table 2 (Example 3, reaction activity R of phenolic resin = 0.5), Experiment No. 11 (Example 4, reaction activity R of phenol resin = 1.0), and Experiment No. 17 (Comparative example 4, reaction activity R = 1.0 of phenolic resin) When using resins with different reaction activities, add the same amount of acid catalyst or a reduced amount of catalyst depending on the increase in reaction activity. However, it is not possible to obtain a foam with a high closed cell ratio, and it is clear that it is important to adjust the amount of addition so that Y expressed in the formula is within the same level range. A comprehensive evaluation of the results in Tables 1 and 2 shows that the foam has a low density, a closed cell ratio of 80% or more, and a good nonflammability test (low smoke coefficient, small temperature-time area). , short afterflame time, no cracks or deformation), low residual acid content, near neutrality, and non-corrosive to metals are marked with an ○, and those with poor performance in any one are marked with an x. The amount of epoxy compound added is
Figure 2 shows the results plotted on orthogonal coordinates with the amount of acid catalyst added (Y) as the Y axis. From Figure 2, coordinate points A (0.060, 0.0475), B
(0.079, 0.0550), C (0.150, 0.070), D (0.060,
Foamed with a composition within the range of 0.0355) has excellent performance, and even when using phenolic resins with different reactivity, excellent foamed products can be produced by foamed with a composition within the above range. It is clear that it will be done. Example 5 20 grams of 1,1,2-trichloro-1,2,2-trifluoroethane diglycerin diglycidyl ether per 100 grams of liquid resol type phenolic resin (viscosity at 25°C 300 poise, reactivity index R=1.0) 0.08 mol was added and mixed uniformly, and 4.9 g (0.05 mol) of orthophosphoric acid was added and mixed uniformly with a high-speed stirrer to foam. The foam was then left in a dryer at 70°C for 20 minutes to complete curing. The obtained foam has a density of 35Kg/m ² and a closed cell ratio.
81%, afterflame time 22 (seconds), smoke generation coefficient 10, temperature time area 2 (°C minutes), and had excellent flame resistance with no cracks or deformation. In addition, the amount of residual acid in the foam was 1.5 x 10 ^-4 mol/g, which gave good results in the corrosion evaluation. Comparative Example 5 Add 15 grams of trichloromonofluoromethane to 100 grams of liquid resol type phenolic resin (viscosity at 25°C, 300 poise, reactivity index R = 1.0), add 12 grams of a 75% aqueous solution of para-toluenesulfonic acid, and stir at high speed. The mixture was mixed uniformly using a machine and foamed. Then, it was left in a dryer at 70°C for 20 minutes to complete curing. The physical properties of the obtained foam are: density 40Kg/m ³ , closed cell ratio 0%, thermal conductivity 0.035 (0°C) Kcal/m・
At hr℃, afterflame time 35 (seconds), smoke generation coefficient 10, temperature time area 2 (℃, minutes), cracks and deformation are large, after the test,
The foam sample was very brittle and powdered. or,
The amount of residual acid in the foam was 5.0 x 10 ^-4 mol/g, and even in a corrosion test using a steel plate in contact with the foam, corrosion occurred on the entire surface, and corrosion progressed inside the steel plate, making it brittle. Comparative Example 6 Foaming was carried out in the same manner as in Example 4 except that 0.06 mol of glycerin diglycidyl ether was replaced with 0.06 mol of bisphenol A diglycidyl ether, and a foam with a density of 33 Kg/m ³ and a closed cell ratio of 74% was obtained. Obtained. As a result of testing the nonflammability of this product, the afterflame time was 33
seconds, smoke generation coefficient 35, temperature time area 20℃ minutes, a crack with a width of 1/5 of the thickness of the test piece appeared on the surface of the test piece, and the deformation was significant after the test, and the residue was brittle and powdered. It was easy.

[Brief explanation of drawings]

FIG. 1 is a diagram showing coordinate points of orthogonal coordinates described in the claims. FIG. 2 is an analysis diagram of an example/comparative example, which is the basis of FIG. 1.

Claims (1)

[Claims] 1. A method for producing a foam by mixing a resol type phenolic resin with an epoxy compound, an acid catalyst, and a blowing agent, wherein the epoxy compound is a compound represented by the general formula [ ], [] Formula (where n is an integer of 1 or more) In the orthogonal coordinates consisting of the X axis defined by the amount of epoxy compound added and the Y axis defined by the amount of acid catalyst added, coordinate point A (0.060, 0.0475) ，
B (0.079, 0.0550), C (0.150, 0.070), D (0.060
，
0.0355) A method for producing phenol foam with excellent flame resistance, characterized by foaming a composition within the range surrounded by The amount of acid catalyst (Y) expressed in [ ] is mol/100g of phenolic resin. ] Y = Acid catalyst addition amount + 0.047 (1-R) ...Formula (wherein, R is the reaction activity index of the resol type phenolic resin) 2 Claims in which the blowing agent is a volatile organic compound with a low boiling point The manufacturing method according to item 1. 3. The manufacturing method according to claim 1, wherein the epoxy compound [ ] is glycerin diglycidyl ether. 4. The production method according to claim 1, wherein the acid catalyst is P-toluenesulfonic acid and/or xylenesulfonic acid.