JPH11140217A - Phenolic foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phenolic foam containing a hydrocarbon as a blowing agent, having an excellent adiabatic performance, excellent mechanical strengths such as compression strength and improved brittleness, and compatible with global environments. SOLUTION: This phenolic foam contains a 4-6C saturated hydrocarbon as a blowing agent, has a closed cell rate of >=80%, an average cell diameter of 10-400 μm and a thermal conductivity of <=0.025 kcal/mhr deg.C. The phenolic foam further contains at least one kind of fluoroether expressed by the formula [(a) is 0,1,2 or 3; (b) is 3-(a); (m) and (n) are each a natural number] in an amount of 0.01-5 wt.% in the phenolic foam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenol foam for heat insulation suitable as various building materials.

[0002]

2. Description of the Related Art Phenol foam is widely used as a building material because of its excellent flame retardancy, heat resistance, low smoke generation, dimensional stability, solvent resistance and workability among organic resin foams. in use. Generally, a phenol foam is produced by uniformly mixing a resol resin obtained by condensing phenol and formalin with an alkaline catalyst, a foaming agent, a surfactant, a curing catalyst, and other additives to foam.

[0003] Conventional phenol foams include trichlorotrifluoroethane (CFC-113) as a blowing agent,
Halogenated hydrocarbons such as trichloromonofluoromethane (CFC-11), dichlorotrifluoroethane (HCFC-123), and dichlorofluoroethane (HCFC-141b) and derivatives thereof have been used. These halogenated hydrocarbons and their derivatives as foaming agents are excellent in safety at the time of production, and have the advantage that the thermal conductivity of the resulting foam can be lowered because the gas itself has low thermal conductivity. Had. However, at present, CF
Substances containing chlorine atoms, such as C-113 and CFC-11,
It has been shown that they degrade stratospheric ozone and cause destruction of the ozone layer, and these substances have become a global issue as a cause of environmental destruction at the global level, and their production and use The amount has become regulated worldwide. Further, 1,1,1,2-tetrafluoroethane (HFC-134a) and 1,1-difluoroethane (HFC-152a), which are chlorine-free fluorocarbons having an ozone depletion potential of 0, are also global warming. Due to the relatively large coefficient, use is being restricted in Europe, and hydrocarbons such as pentane have attracted attention.

[0004] Conventionally, it has been known to use hydrocarbons such as normal pentane and cyclopentane as blowing agents for phenol foam, but these hydrocarbons do not destroy the ozone layer and cause global warming. Although the coefficient is excellent in that the coefficient is relatively small, the average foam diameter of the foam is larger than the halogenated hydrocarbon, and the thermal conductivity of the gas itself is low, so that good heat insulating performance cannot be obtained. However, there are practical problems such as poor mechanical strength such as compressive strength.

On the other hand, Japanese Patent Publication No. 4-503829 discloses a phenol foam having a low thermal conductivity by mixing a specific fluoroalkane (hereinafter referred to as PFA) with an alkane or cycloalkane and using it as a blowing agent. However, since the fluoroalkane also has a relatively large global warming potential like the above-mentioned fluorohydrocarbons, there is a concern that its use may be restricted.

[0006] In Japanese Patent Application Laid-Open No. 3-231941, phenol foam is produced by using a specific polyfluoroether as a foaming agent. Further, in JP-A-4-202242, a phenol foam is produced by using a specific fluorinated ether as a main component of a blowing agent. The specific polyfluoroethers and specific fluorinated ethers used in JP-A-3-231941 and JP-A-4-202242 have low thermal conductivity of the gas itself and low global warming potential. Although relatively small, the present inventors have found that when these ethers are used as a foaming agent, the resulting phenol foam has a large cell diameter, the rigidity of the resin forming the foam decreases, and the compressive strength of the foam against the density of the foam decreases. It has been found that there is a problem that the value is relatively small.

[0007]

SUMMARY OF THE INVENTION The present invention can solve the above problems of the conventional phenol foam. That is, an object of the present invention is to provide a phenol foam which is a hydrocarbon foaming agent, has excellent heat insulating performance, has excellent mechanical strength such as compressive strength, has improved brittleness, and is more suitable for the global environment. And

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found out the existence of a phenol foam which can achieve the object of the present invention, and have completed the present invention. That is, the present invention provides: The blowing agent is a saturated hydrocarbon having 4 to 6 carbon atoms,
The closed cell ratio is 80% or more, and the average cell diameter is 10 μm or more4
00 μm or less, thermal conductivity of 0.025 kcal / mhr
C. or less, wherein the phenol foam is obtained by adding at least one fluoroether represented by the following general formula (1) to the phenol foam in an amount of 0.0
A phenol foam containing 1 to 5% by weight;

[0009]

Embedded image

In the formula (1), a is 0, 1, 2, 3 and b is 3-a, m and n are natural numbers. 2. The phenol foam according to the above 1, wherein the density is 10 kg / m ³ or more and 70 kg / m ³ or less, the brittleness is 30% or less, and the compressive strength satisfies the relationship of the formula (2) with respect to the density. 2. Phenol foam, compressive strength [kg / cm ² ] ≧ density [kg / m ³ ] × 0.1164-2.5 (2) The blowing agent is a saturated hydrocarbon having 4 to 6 carbon atoms containing at least one fluoroether represented by the general formula (1) in an amount of 0.2 to 20% by weight based on the blowing agent. 3. The phenol foam according to the above 1 or 2.

Hereinafter, the present invention will be described in detail. The phenol foam of the present invention needs to have a closed cell rate of 80% or more. It is more preferably at least 85%, further preferably at least 90%. If the closed cell ratio is less than 80%, not only the foaming agent of the phenol foam may be replaced by air but the heat insulation performance may deteriorate significantly with time, but also the surface brittleness of the foam may increase and the mechanical practical performance may increase. May not be satisfied.

The average cell diameter of the phenol foam in the present invention is from 10 μm to 400 μm, more preferably from 20 μm to 200 μm. When the average cell diameter is less than 10 μm, there is a limit to the thickness of the cell wall, so that the foam density inevitably increases, and as a result, the heat transfer ratio of the resin part in the foam increases, and the heat insulation performance of the phenol foam increases. May be insufficient. On the other hand, when the cell diameter exceeds 400 μm, heat conduction by radiation increases, and the heat insulating performance of the foam decreases.

The phenol foam of the present invention uses an alkane or cycloalkane having 4 to 6 carbon atoms as a blowing agent. Specifically, normal butane, isobutane, normal pentane, isopentane, cyclopentane, neopentane, normal hexane, isohexane,
Examples thereof include 2,2-dimethylbutane, 2,3-dimethylbutane, and cyclohexane. Furthermore, among them, normal butane, isobutane, normal pentane,
Butanes such as isopentane, cyclopentane and neopentane or pentanes are particularly suitable for the present invention. In the present invention, two or more of these hydrocarbons may be used in combination. Examples of mixing include normal pentane and normal butane, isobutane and isopentane, normal butane and isopentane, isobutane and normal pentane,
There is a mixture of cyclopentane and normal butane, and a mixture of cyclopentane and isobutane. In addition, a low-boiling substance such as nitrogen, helium, argon, or air can be used as a foaming core dissolved in a foaming agent.

The amount of the foaming agent used in the present invention may be appropriately determined depending on the desired density of the foam, foaming conditions and the like.
The amount is preferably 0 parts by weight, more preferably 5 to 20 parts by weight. The fluoroether of the present invention is a fluoroether having both a perfluoropropyl ether structure and a fluoromethylene structure in the molecule. For example, Galden HT-70, which is a perfluoropolyether manufactured by Audimont Corporation, Galden (Galden) HT-55 or the like can be preferably used.

The amount of the fluoroether of the present invention is from 0.01% by weight to 5% by weight based on the phenol foam.
And more preferably 0.05 to 3% by weight.
It is. If the amount of the fluoroether is less than 0.01% by weight, a high closed cell rate cannot be obtained. On the other hand, when the amount of the fluoroether exceeds 5% by weight, not only is the production cost increased, which is economically disadvantageous, but also the specific fluoroether is liquefied in the bubbles to lower the heat insulation performance, and the rigidity of the resin is reduced. There is a concern that this will decrease.

When the fluoroether of the present invention is used alone as a foaming agent, the fluoroether is rapidly separated from the resin phase during foaming, and a foam is not obtained, and the phenol resin is agglomerated. Was. This is because the fluoroether of the present invention is disclosed in
This is because, unlike the specific polyfluoroethers and the specific fluorinated ethers used in JP-A-31941 and JP-A-4-202242, they do not have a foaming function as a foaming agent.

In the present invention, by using a hydrocarbon as a foaming agent and coexisting with a fluoroether at the time of foaming, the cell diameter of the phenol foam is reduced, and at the same time a high closed cell rate is obtained, thereby significantly improving the heat insulating performance. It will improve. The phenol foam according to the present invention comprises
Although the blowing agent is a hydrocarbon, the thermal conductivity is 0.025.
kcal / mhr ° C. or less, and has excellent heat insulating performance. More preferable thermal conductivity is 0.020 kcal / mh.
r ° C. or less.

Further, the fluoro compound according to the present invention has a shorter life in the air and a relatively lower global warming potential than perfluoroalkanes because oxygen is present in the molecule, and is therefore suitable for protecting the global environment. It has the great advantage of being compatible. The density of the phenol foam of the present invention can be selected as desired from foaming conditions such as the ratio of a foaming agent and the oven temperature during curing, but is preferably 10 kg / m ³ or more and 70 kg / m ³ or less, more preferably Is 20kg
/ M ³ or more and 50 kg / m ³ or less. Density is 10kg /
If it is less than m ³ , the mechanical strength such as the compressive strength will be low, and it will be easily broken during handling, and the surface brittleness will also increase. Conversely, if the density exceeds 70 kg / m ³ , the heat transfer of the resin portion increases, and the heat insulation performance may decrease.

The phenol foam according to the present invention also has improved brittleness and compressive strength compared to conventional phenol foam. Although the reason for this is not clear, the coexistence of the fluoroether with the blowing agent at the time of foaming causes foaming to occur more uniformly and at a more favorable timing, thereby reducing the cell diameter of the resulting phenol foam and reducing these compounds. Is presumed to make the resin structure itself that forms the bubbles stronger. The phenol foam of the present invention has a brittleness of 30% or less, more preferably 20% or less, in the above-mentioned density range according to a measuring method described later. If the brittleness exceeds 30%, there is a problem that not only the resin powder whose surface of the foam is shaved increases and the workability at the time of construction is lowered, but also that the product is easily damaged at the time of handling such as transportation and construction. Not practically preferable.

The compressive strength of the phenol foam of the present invention preferably satisfies the relationship of the above formula (2) with respect to the density. The phenol foam according to the present invention is remarkably improved also in that the phenol foam has a higher compressive strength with respect to density as compared with the foam described in JP-A-4-202242. The brittleness and the compressive strength are closely related to the closed cell ratio, the average cell diameter, the density of the phenol foam and the strength of the resin itself, and are particularly highly dependent on the density.

In the phenol foam using a hydrocarbon as a blowing agent as in the present invention, the presence of the fluoroether reduces the average cell diameter as compared with the conventional phenol foam, further improves the strength of the resin, and reduces the compression against the density. It is considered that the balance between strength and brittleness is the root of forming a phenol foam having an excellent balance. next,
The method for producing a phenol foam according to the present invention will be described.

The resole resin, which is a resin raw material, is prepared by using phenol and formalin as raw materials at 40 ° C. with an alkali catalyst.
From 100 to 100 ° C. for polymerization. This resole resin may be used by adding various modifiers such as urea, amines, amides, epoxy compounds, monosaccharides, starches, poval resins, furan resins, polyvinyl alcohol, lactones and the like. . In the case of urea modification, urea may be added at the time of resole resin polymerization, or urea previously methylolated with an alkali catalyst may be mixed with the resole resin. The resole resin composition is used at an appropriate viscosity by adjusting the amount of water.
The preferred viscosity of the resin composition varies depending on the foaming conditions.
The viscosity at ° C is preferably from 1,000 to 50,000 cps, more preferably from 2,000 to 30,000 cps.

A resol resin composition adjusted to an appropriate viscosity, a foaming agent, a specific fluoroether, a surfactant,
The foaming composition can be obtained by introducing the curing catalyst into the mixer and mixing it uniformly. At that time, the surfactant may be previously mixed with the resin and introduced into the mixer, or these may be separately introduced into the mixer. In the present invention, the method of introducing a specific fluoroether is not particularly limited,
For example, a method in which a specific fluoroether is mixed with a resin in advance and introduced into the mixer with the resin, a method in which the resin is introduced into the mixer with the curing catalyst, a method in which the resin is introduced together with the blowing agent, or a method in which the resin is introduced alone into the mixer Any method is acceptable.

However, a method in which a specific fluoroether is mixed with a foaming agent in advance and introduced into the mixer together with the foaming agent is more preferable since the expected effect is exhibited even in a relatively small amount. When a specific fluoroether is previously mixed with the blowing agent, the ratio of the specific fluoroether to the blowing agent may be from 0.2% by weight to 20% by weight. When mixed with a blowing agent, if the amount of the specific fluoroether is less than 0.2% by weight with respect to the blowing agent, no effect will be exhibited.
If it exceeds 0% by weight, there is a concern that the heat insulation performance and mechanical strength of the phenol foam may be reduced. It is more preferably from 0.5% to 15% by weight, particularly preferably from 1% to 10% by weight. In addition, if the curing catalyst is previously mixed with the resole resin, the curing reaction proceeds before foaming and a good foam cannot be obtained. Therefore, it is desirable to mix the resole resin and the curing catalyst with a mixer. The foamable composition obtained by mixing with a mixer is poured into a mold or the like, and the foaming and curing is completed by heat treatment, whereby the phenol foam of the present invention can be obtained.

In the present invention, as a curing catalyst for foaming and curing, aromatic sulfonic acids such as toluene sulfonic acid, xylene sulfonic acid, benzene sulfonic acid, phenol sulfonic acid, styrene sulfonic acid, naphthalene sulfonic acid or the like may be used alone or in combination. These can be mixed and used. Further, resorcinol, cresol, saligenin (o-methylolphenol), p-methylolphenol, etc. may be added as a curing aid. Further, these curing catalysts may be diluted with a solvent such as diethylene glycol or ethylene glycol.

The surfactant used in the present invention may be a usual one used for producing phenol foam. Among them, nonionic surfactants are effective, for example, alkylene oxide, which is a copolymer of ethylene oxide and propylene oxide, a condensate of alkylene oxide and castor oil, or alkylene oxide and nonylphenol, such as dodecylphenol Specific examples thereof include condensation products with a suitable alkylphenol, fatty acid esters such as polyoxyethylene fatty acid esters, silicone-based compounds such as polydimethylsiloxane, and polyalcohols. These surfactants may be used alone or in combination of two or more. The amount of use is not particularly limited, but in the present invention, it is more effective to use it in the range of 0.3 to 10 parts by weight per 100 parts by weight of the resole resin.

Next, a method for evaluating the structure, structure and properties of the phenol foam in the present invention will be described. The closed cell ratio of the phenol foam was measured as follows. A cylindrical sample of 35 to 36 mm in diameter, cut through a phenol foam with a cork borer, was placed at a height of 30 to 4 mm.
The sample volume is cut to 0 mm, and the sample volume is measured by a standard use method of an air comparison specific gravity meter 1000 (manufactured by Tokyo Science). ASTM D is a value obtained by subtracting the volume of the cell wall calculated from the sample weight and the resin density from the sample volume and dividing by the apparent volume calculated from the outer size of the sample.
It was measured according to 2856. In the present invention, the density of the phenol resin was 1.27 g / cm ³ .

The average cell diameter of the phenol foam in the present invention is defined as the average value of the number of cells crossed by four straight lines of 9 cm length on a 50-fold enlarged photograph of the cross section of the foam, and 1800 μm. The value is divided by JIS K64
It is an average value calculated from the number of cells measured according to No. 02. Thermal conductivity is phenol foam sample 200mm
It was measured at a square, a low temperature plate of 5 ° C. and a high temperature plate of 35 ° C. according to the flat plate heat flow method of JIS A1412. The density is a value obtained by measuring a weight and an apparent volume by removing a face material and a siding material from a phenol foam of 20 cm square as a sample, and was measured according to JIS K7222.

As a test piece for the brittle test, 12 cubes each having a side of 25 ± 1.5 mm were cut out so as to include a molded skin or face material on one face, and used as a sample. However, when the thickness of the foam was less than 25 mm, the thickness of the test piece was the thickness of the foam. Room temperature dried specific gravity 0.65, one side 19 ± 0.
24 x 8 mm oak cubes and 12 test pieces can be sealed to prevent dust from coming out of the box.
Place in a 97 mm oak wooden box and spin 600 ± 3 at a rate of 60 ± 2 revolutions per minute. After the rotation is completed, the contents of the box are transferred to a net having a nominal size of 9.5 mm, sieved to remove small pieces, the weight of the remaining test piece is measured, and the reduction rate from the weight of the test piece before the test is calculated. Is brittle, JIS A
9511.

The compressive strength was measured according to JIS K7220 with a specified strain of 0.05. Confirmation of the content of the blowing agent and the specific fluoroether in the phenol foam can be performed as follows. Standard temperature condition 3 specified in JIS K 7100 for a test piece of 50 × 50 × thickness mm
After maintaining in a class (temperature 23 ± 5 ° C.) and standard humidity state class 3 (relative humidity 40 to 70%) for 16 hours or more, the surface agent is removed and the weight is precisely weighed. The test piece is pulverized with a solvent selected from pyridine, toluene, DMF, or the like in an airtight container, and a blowing agent and a specific fluoroether are extracted and quantified by gas chromatography or liquid chromatography. If necessary, the components separated by gas chromatography may be introduced into a mass spectrometer to confirm the molecular structure. Alternatively, LC-IR (liquid chromatography-infrared absorption spectrometer)
May be used to continuously identify the extracted components.

[0031]

Now, the present invention will be described in further detail with reference to Examples and Comparative Examples. (A) Synthesis of resole resin In a reactor, 5000 g of 37% formalin (Wako Pure Chemical Industries, special grade reagent) and 3,000 g of 99% phenol (Wako Pure Chemical Co., special grade reagent) were charged, and the propeller rotating stirrer was used. Stir and adjust the temperature of the liquid inside the reactor to 40 ° C with a temperature controller.
Adjust to Next, 60 g of a 50% aqueous sodium hydroxide solution was added, and the reaction solution was heated from 40 ° C. to 85 ° C.
Hold for 0 minutes. Thereafter, the reaction solution is cooled to 5 ° C.
This is designated as resol resin A-1.

On the other hand, 37% formalin 10
80 g, 1000 g of water and 78 g of a 50% aqueous sodium hydroxide solution were added thereto, and urea (special grade reagent, Wako Pure Chemical Industries, Ltd.) 16
Then, the mixture was stirred with a propeller rotary stirrer, and the temperature inside the reactor was adjusted to 40 ° C. with a temperature controller. Next, the reaction solution was heated from 50 ° C. to 70 ° C.
Hold for minutes. This is referred to as methylol urea U. Next, 1350 of methylol urea U was added to the resole resin A-1.
g, and the solution temperature was raised to 60 ° C. and maintained for 1 hour.
The reaction was then cooled to 30 ° C. and neutralized with a 50% aqueous solution of paratoluenesulfonic acid monohydrate until the pH reached 6. The reaction solution was dehydrated at 60 ° C., and the viscosity was measured. The viscosity at 40 ° C. was 6,700 cps. This is designated as resol resin A.

(B) Synthesis of Resol Resin A reactor was charged with 4350 g of 37% formalin and 3000 g of 99% phenol, and stirred with a propeller rotating stirrer, and the temperature inside the reactor was adjusted to 50 ° C. with a temperature controller. I do. Then, a 50% aqueous sodium hydroxide solution was added to 60
g was added, and the reaction solution was kept at 50 to 55 ° C. for 20 minutes. Thereafter, the temperature was raised to 85 ° C., and was maintained for 115 minutes after the temperature reached 85 ° C. Thereafter, the reaction solution was cooled to 30 ° C. and neutralized with a 50% aqueous solution of paratoluenesulfonic acid monohydrate until the pH reached 6. This reaction solution is
After dehydration treatment at ℃, the viscosity was measured at 40 ℃ was 5800 cps. This is designated as resol resin B.

[0034]

Example 1 Paintad 32 (a surfactant manufactured by Dow Corning Asia Co., Ltd.) was dissolved in resole resin A at a ratio of 3.5 g to 100 g of resole resin. This resole resin mixture, isopentane as a foaming agent (manufactured by Wako Pure Chemical Industries, Ltd., purity: 99% or more) 96.7% by weight, Galden HT-70 (manufactured by Ausimond Co., Ltd.) 3% by weight, nitrogen 0.3 % By weight of a mixture and 60% by weight of paratoluenesulfonic acid monohydrate as a curing catalyst
A mixture of (Wako Pure Chemical Co., purity 95% or more) and diethylene glycol 40% by weight (Wako Pure Chemical Co., purity 98% or more), respectively, 100 parts by weight of a resin mixture, 7 parts by weight of a foaming agent, and 13 parts by weight of a curing catalyst Parts to a pin mixer equipped with a temperature control jacket. The mixture coming out of the mixer was poured into a formwork on which Spunbond E1040 (non-woven fabric manufactured by Asahi Kasei Kogyo Co., Ltd.) was spread, placed in an oven at 80 ° C., and kept for 5 hours to produce a phenol foam.

[0035]

Example 2 The blowing agent was changed to a mixture of 79.7% by weight of isopentane, 7020.0% by weight of Galden HT-702 and 0.3% by weight of nitrogen, and the amount of the blowing agent was changed to 8.5 parts by weight. A phenol foam was produced in exactly the same manner as in Example 1 except for the above.

[0036]

Example 3 Galden (Gal) was added to a resole resin mixture.
den) HT-70 was dissolved in 5% by weight based on the resin mixture, and phenol was used in the same manner as in Example 1 except that the mixture was changed to a mixture of 99.7% by weight of isopentane and 0.3% by weight of nitrogen as a blowing agent. Made foam.

[0037]

Example 4 Phenol foam was prepared in exactly the same manner as in Example 1, except that the blowing agent was changed to a mixture of 99.5% by weight of isopentane, 700.2% by weight of Galden HT-70% by weight and 0.3% by weight of nitrogen. Was manufactured.

[0038]

EXAMPLE 5 Resol resin A was changed to resol resin B, and 93.7% by weight of isopentane, 7% by weight of Galden HT-707 and 0.3% of nitrogen were used as blowing agents.
A phenol foam was produced in exactly the same manner as in Example 1 except that the mixture was changed to a weight% mixture.

[0039]

Example 6 Normal pentane (manufactured by Wako Pure Chemical Industries, special grade reagent) was used at 89.7% by weight of a blowing agent, and Galden (Galde) was used.
n) except that the mixture was changed to a mixture of 10% by weight of HT-70 and 0.3% by weight of nitrogen and the amount of the blowing agent was changed to 7.7 parts by weight.
A phenol foam was produced in exactly the same manner as in Example 1.

[0040]

Example 7 The blowing agent was changed to a mixture of 97.7% by weight of normal butane (purity of 99% or more, manufactured by SK Sangyo Co., Ltd.), 2% by weight of Galden HT-70, and 0.3% by weight of nitrogen. A phenol foam was produced in exactly the same manner as in Example 1 except that the amount of the foaming agent was changed to 5 parts by weight.

[0041]

Example 8 98.7% by weight of isobutane (manufactured by SK Sangyo Co., Ltd., purity: 99% or more) and Galden (G
alden) HT-70 1% by weight, nitrogen 0.3% by weight
And a phenol foam was produced in exactly the same manner as in Example 1 except that the amount of the blowing agent was changed to 5 parts by weight.

[0042]

EXAMPLE 9 96.7% by weight of isopentane, Galden HT-553% by weight, and 0.1% of nitrogen were used as blowing agents.
A phenol foam was produced in exactly the same manner as in Example 1, except that the mixture was changed to a mixture of 3% by weight.

[0043]

Example 10 Except that the amount of the foaming agent was changed to 13 parts by weight,
A phenol foam was produced in exactly the same manner as in Example 1.

[0044]

Comparative Example 1 Galden (Gal) was added to a resole resin mixture.
den) HT-70 was dissolved in 15% by weight based on the resin mixture, and phenol was prepared in the same manner as in Example 1 except that a mixture of 99.7% by weight of isopentane and 0.3% by weight of nitrogen was used as a blowing agent. Made foam.

[0045]

Comparative Example 2 A phenol foam was produced in exactly the same manner as in Example 1 except that the blowing agent was changed to a mixture of 99.7% by weight of isopentane and 0.3% by weight of nitrogen.

[0046]

Comparative Example 3 Phenol foam was prepared in exactly the same manner as in Example 1 except that the blowing agent was changed to a mixture of 99.6% by weight of isopentane, 700.1% by weight of Galden HT-70% and 0.3% by weight of nitrogen. Was manufactured.

[0047]

Comparative Example 4 A phenol foam was prepared in the same manner as in Example 1 except that the blowing agent was changed to a mixture of 99.7% by weight of isopentane and 0.3% by weight of nitrogen, and the amount of the blowing agent was changed to 13 parts by weight. Manufactured.

[0048]

Comparative Example 5 A phenol foam was prepared in the same manner as in Example 1 except that the resol resin A was changed to the resol resin B and the blowing agent was changed to a mixture of 99.7% by weight of isopentane and 0.3% by weight of nitrogen. Manufactured. The raw resin, closed cell ratio, average cell diameter, thermal conductivity, fluoroether content in the foam, density, brittleness and compressive strength of the phenol foam samples obtained in the above Examples and Comparative Examples are summarized in Table 1. Shown.

[0049]

[Table 1]

[0050]

The phenol foam according to the present invention has excellent heat insulating performance, excellent mechanical strength such as compressive strength,
The surface brittleness is significantly improved. Since the foam according to the present invention uses a blowing agent having a low global warming coefficient without fear of destruction of the ozone layer, it is suitable as a building insulation material more suitable for the global environment.

Claims (3)

[Claims] The foaming agent is a saturated hydrocarbon having 4 to 6 carbon atoms, the closed cell ratio is 80% or more, and the average cell diameter is 10 μm.
m to 400 μm, thermal conductivity is 0.025 kcal
/ Mhr ° C or lower, characterized in that the phenol foam contains at least one fluoroether represented by the following general formula (1) in an amount of 0.01 to 5% by weight based on the phenol foam. Phenol foam. Embedded image In the formula (1), a is 0, 1, 2, 3 and b is 3-
a and m and n are natural numbers. 2. A phenol foam having a density of 10 kg /
2. The phenol foam according to claim 1, wherein the phenolic foam has an m ³ or more and 70 kg / m ³ or less, the brittleness is 30% or less, and the compressive strength satisfies the relationship of the formula (2) with respect to the density. Compressive strength [kg / cm ² ] ≧ density [kg / m ³ ] × 0.1164-2.5 (2) 3. A blowing agent comprising at least one fluoroether represented by the above general formula (1) in an amount of 0.1 to 1.0 parts with respect to the blowing agent.
The phenol foam according to claim 1 or 2, which is a saturated hydrocarbon having 4 to 6 carbon atoms containing 2 to 20% by weight.