JPH11140216A - Phenolic resin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phenolic resin 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 resin foam contains a low boiling point 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 resin foam further contains a high boiling point aliphatic hydrocarbon and/or an aliphatic hydrocarbon in a total amount of 0.01-10 wt.%. The blowing agent is preferably a 4-6C saturated hydrocarbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-insulating phenolic resin foam suitable as various building materials.

[0002]

2. Description of the Related Art Phenolic resin foams are excellent in flame retardancy, heat resistance, low smoke generation, dimensional stability, solvent resistance and workability among organic resin foams. Widely used. In general, a phenolic resin 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 phenolic resin foams use trichlorotrifluoroethane (CFC-11) as a blowing agent.
3), trichloromonofluoromethane (CFC-1)
1), dichlorotrifluoroethane (HCFC-12
3), dichlorofluoroethane (HCFC-141b)
Halogenated hydrocarbons 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, it has been revealed that substances containing chlorine atoms, such as CFC-113 and CFC-11, decompose stratospheric ozone and cause destruction of the ozone layer. The cause of environmental destruction has become a global problem, and their production and use have been regulated worldwide. In addition, 1,1, which is a fluorohydrocarbon having an ozone destruction coefficient of 0 containing no chlorine.
1,2-tetrafluoroethane (HFC-134a),
Since 1,1-difluoroethane (HFC-152a) and the like also have a relatively large global warming potential, their use is being restricted in Europe, and hydrocarbons such as pentane have been attracting attention.

[0004] Conventionally, it has been known to use hydrocarbons such as normal pentane and cyclopentane as blowing agents for phenolic resin foams. However, these hydrocarbons do not destroy the ozone layer, and do not cause global warming. Although the conversion coefficient is also relatively small, the foam has a larger average cell diameter than the halogenated hydrocarbons, and the heat conductivity of the gas itself is low.
In addition, there are practical problems such as a weak cell wall and insufficient mechanical strength such as compressive strength. On the other hand, special publication Hei 4
In JP-A-503829, a phenolic resin foam having a low thermal conductivity is produced by mixing a specific fluoroalkane (hereinafter referred to as PFA) with an alkane or a cycloalkane and using it as a foaming agent. Because of its relatively high global warming potential, similar to fluorocarbons, there are concerns about restrictions on use.

[0005]

SUMMARY OF THE INVENTION The present invention can solve the above-mentioned problems of the conventional phenol resin foam. That is, the present invention provides a phenolic resin foam that is a hydrocarbon blowing agent, has excellent heat insulating performance, and has excellent mechanical strength such as compressive strength, has improved brittleness, and is more suitable for the global environment. Make it an issue.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found out the existence of a phenolic resin 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 hydrocarbon having a low boiling point and a closed cell ratio of 80
% Or more, an average cell diameter of 10 μm or more and 400 μm or less, and a thermal conductivity of 0.025 kcal / mhr ° C. or less, wherein the phenol resin foam is a high-boiling aliphatic hydrocarbon or a high-boiling alicyclic resin. 1. A phenolic resin foam characterized in that it contains 0.01 to 10% by weight of a hydrocarbon or a mixture thereof based on the phenolic resin foam. 2. The phenolic resin foam according to the above 1, wherein the blowing agent is a saturated hydrocarbon having 4 to 6 carbon atoms. Density is 10 kg / m ³ or more and 70 kg / m ³ or less, brittleness is 30% or less, and compressive strength is 0.5 kg / cm ^2.
3. The phenolic resin foam according to the above item 1 or 2, wherein The blowing agent is a low-boiling hydrocarbon containing 0.2 to 50% by weight, based on the blowing agent, of a high-boiling aliphatic hydrocarbon or a high-boiling alicyclic hydrocarbon or a mixture thereof. The phenolic resin foam according to the above 1, 2, or 3.

Hereinafter, the present invention will be described in detail. The phenolic resin 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%. When the closed cell ratio is less than 80%, the foaming agent of the phenolic resin foam is replaced with air, and not only the heat insulation performance may be significantly reduced with time, but also the surface brittleness of the foam may increase to make it practically usable. There is a concern that performance will not be satisfied.

The average cell diameter of the phenolic resin 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 portion in the foam increases, and the heat insulation of the phenol resin foam increases. Performance 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 phenolic resin foam of the present invention uses a low-boiling hydrocarbon as a blowing agent. That is, as the blowing agent, a cyclic or chain alkane, alkene, or alkyne having 3 to 7 carbon atoms can be preferably used. Further, from the viewpoints of chemical stability and thermal conductivity, an alkane or cycloalkane having 4 to 6 carbon atoms is more preferable. In particular,
Normal butane, isobutane, normal pentane, isopentane, cyclopentane, neopentane, normal hexane, isohexane, 2,2-dimethylbutane, 2,
Examples thereof include 3-dimethylbutane and cyclohexane. Among them, butanes such as normal butane and isobutane, and pentanes such as normal pentane, isopentane, cyclopentane and neopentane are particularly suitable for the present invention.

In the present invention, two or more of these hydrocarbons can be used in combination. Examples of mixing include normal pentane and normal butane, isobutane and isopentane, normal butane and isopentane, isobutane and normal pentane, cyclopentane and normal butane,
There is a mixture of cyclopentane and isobutane. Further, 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, but is usually preferably 2 to 40 parts by weight based on 100 parts by weight of the resin. Preferably it is 3 to 20 parts by weight.

In the present invention, the high-boiling aliphatic hydrocarbon or the high-boiling alicyclic hydrocarbon or a mixture thereof is
It is preferable that the normal boiling point at one atmosphere is 150 ° C. or higher and the hydrocarbon is mainly an alkane structure or a cycloalkane structure, specifically, solid paraffin, liquid paraffin, mineral spirit, low molecular weight polyethylene, Examples include low molecular weight polypropylene.
Solid paraffin is also called paraffin wax and has 1 carbon atom.
It is distributed in the range of 6 to 60 and mainly consists of normal paraffin, but many contain isoparaffin and naphthene,
Usually, the melting point changes from 35 ° C. to about 80 ° C. Liquid paraffin is a hydrocarbon oil whose pour point is usually -20 ° C or higher and a relatively light lubricating oil fraction, for example, a spindle oil fraction, is highly refined by washing with sulfuric acid. Ingredients. Mineral spirit is also called petroleum spirit and is defined in Japanese Industrial Standard K2201 (Industrial Gasoline Standard) No. 4.

The amount of the high-boiling aliphatic hydrocarbon or high-boiling alicyclic hydrocarbon or a mixture thereof according to the present invention is from 0.01% by weight to 10% by weight based on the phenolic resin foam.
% By weight, more preferably from 0.05% by weight to 5% by weight.
% By weight. If the amount of the high-boiling aliphatic hydrocarbon or high-boiling alicyclic hydrocarbon or a mixture thereof is less than 0.01% by weight, a high closed cell rate cannot be obtained. Also,
When the weight exceeds 10% by weight, the high-boiling aliphatic hydrocarbon or the high-boiling alicyclic hydrocarbon or a mixture thereof is liquefied in the air bubbles to lower the heat insulation performance or the rigidity of the resin. Is concerned about

[0013] The present invention is to reduce the bubbles of the phenolic resin foam by the presence of a high-boiling aliphatic hydrocarbon or a high-boiling alicyclic hydrocarbon or a mixture thereof at the time of foaming, while at the same time having a high closed cell rate and None, thereby significantly improving the thermal insulation performance of the phenolic foam. The phenolic resin foam according to the present invention has a thermal conductivity of 0.0 while the blowing agent is a hydrocarbon.
It is 25 kcal / mhr ° C or less, and has excellent heat insulating performance. More preferred thermal conductivity in the present invention is 0.0
It is 20 kcal / mhr ° C or less.

The high-boiling aliphatic hydrocarbons or high-boiling alicyclic hydrocarbons or mixtures thereof of the present invention do not vaporize at room temperature and thus do not affect global warming and are suitable for protecting the global environment. Have the advantages. The density of the phenolic resin foam according to the present invention, the proportion of the blowing agent,
A desired value may be selected depending on foaming conditions such as oven temperature during curing, but is preferably 10 kg / m ³ or more and 70 kg.
/ M ³ or less, more preferably 20 kg / m ³ or more and 50 kg / m ³ or less. When the density is less than 10 kg / m ³ , the mechanical strength such as the compressive strength is reduced, the material is easily broken during handling, and the surface brittleness is increased. Conversely, the density is 7
If it exceeds 0 kg / m ³ , the heat transfer of the resin portion may increase and the heat insulation performance may decrease.

The phenolic resin foam according to the present invention has significantly improved brittleness and compressive strength as compared with conventional phenolic resin foams. The reason for this is not clear,
When the high-boiling aliphatic hydrocarbon or the high-boiling alicyclic hydrocarbon or a mixture thereof coexists with the foaming agent at the time of foaming, foaming occurs more uniformly at a more favorable timing, and as a result, the resulting phenol is obtained. It is presumed that as the cell diameter of the resin foam becomes smaller, these compounds further strengthen the structure of the resin itself forming the cells. In the above-mentioned density range, the phenolic resin foam of the present invention has a brittleness of 30% or less, more preferably 20% or less, according to a measuring method described later. When the brittleness exceeds 30%, the foam surface is shaved in practical use, and the generation of resin powder increases, and not only the workability during construction decreases, but also
There is a problem that the product is easily damaged during handling such as transportation and construction, which is not preferable in practical use.

The compressive strength of the phenolic resin foam of the present invention is 0.5 kg / cm ² or more, more preferably 1.0 kg / cm ² or more. Compressive strength 0.5kg
When it is less than / cm ² , not only is it easy to break during construction or the like, but also its use in practical use is limited due to its low mechanical strength. The brittleness and compressive strength are closely related to the closed cell ratio, average cell diameter, density of the phenolic resin foam and the strength of the resin itself, and are particularly dependent on the density. In a phenolic resin foam using a hydrocarbon as a blowing agent as in the present invention, the presence of a high-boiling aliphatic hydrocarbon or a high-boiling alicyclic hydrocarbon or a mixture thereof is more average than that of a conventional phenol resin foam. This is considered to be the root of forming a phenolic resin foam having a small cell diameter, further improving the strength of the resin, and having an excellent balance of compressive strength and brittleness with respect to density.

Next, a method for producing a phenolic resin foam according to the present invention will be described. The resole resin as a resin raw material is obtained by heating and polymerizing phenol and formalin as raw materials in a temperature range of 40 ° C. to 100 ° C. with an alkali catalyst. This resole resin includes urea, amines, amides, epoxy compounds, monosaccharides, starches,
Various modifiers such as poval resin, furan resin, polyvinyl alcohol and lactones may be added for use. 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.
00 cps, preferably 2000 to 300
More preferably, it is 00 cps.

A resol resin composition adjusted to an appropriate viscosity, a blowing agent, a high-boiling aliphatic hydrocarbon or a high-boiling alicyclic hydrocarbon or a mixture thereof, a surfactant, and a curing catalyst are mixed in a mixer. It can be introduced and uniformly mixed to obtain a foamable composition. 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 high-boiling aliphatic hydrocarbon or a high-boiling alicyclic hydrocarbon or a mixture thereof into a mixer is not particularly limited. Any of a method of introducing into a mixer with a resin, a method of introducing into a mixer with a curing catalyst, a method of introducing with a foaming agent, and a method of introducing alone into a mixer may be used.

However, it is more preferable to mix the foaming agent with the foaming agent in advance and introduce it into the mixer together with the foaming agent, since the desired effect is exhibited even with a relatively small amount. In the present invention, the proportion of the high-boiling aliphatic hydrocarbon or high-boiling alicyclic hydrocarbon or a mixture thereof to the blowing agent is as follows:
What is necessary is just to be 0.2 to 50 weight%. If the amount of the high-boiling aliphatic hydrocarbon or the high-boiling alicyclic hydrocarbon or a mixture thereof is less than 0.2% by weight, no effect is obtained. There is a concern that the thermal insulation performance and mechanical strength of the foam may be reduced. The amount of high boiling hydrocarbons relative to the blowing agent is more preferably from 0.5% to 20% by weight, particularly preferably from 1% to 10% by weight.

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 hardening is completed by a heat treatment, whereby a phenol resin foam can be obtained.

In the present invention, an aromatic sulfonic acid such as toluene sulfonic acid, xylene sulfonic acid, benzene sulfonic acid, phenol sulfonic acid, styrene sulfonic acid, naphthalene sulfonic acid or the like is used alone or as a curing catalyst for foaming and curing. More than one kind 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 before use.

The surfactant used in the present invention may be a usual one used for producing a phenolic resin 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 Condensation products with various alkylphenols, and further fatty acid esters such as polyoxyethylene fatty acid esters,
Specific examples include silicone compounds such as polydimethylsiloxane, polyalcohols, and the like. These surfactants may be used alone or in combination of two or more. There is no particular limitation on the amount used, but in the present invention, it is effective to use 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 phenolic resin foam according to the present invention will be described. The closed cell ratio of the phenol resin foam was measured as follows. A cylinder sample of 35 to 36 mm in diameter cut through a phenolic resin foam with a cork borer is cut to a height of 30 to 40 mm, and an air comparison specific gravity meter 10
The sample volume is measured according to the standard use method of Model 00 (manufactured by Tokyo Science). 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 dimensions of the sample,
It was measured according to STM D2856. In the present invention, the density of the phenol resin was 1.27 g / cm ³ . The average cell diameter of the phenolic resin foam in the present invention is defined as a straight line having a length of 9 cm on a 50-fold enlarged photograph of the cross section of the foam.
In this drawing, the average number of bubbles crossed by each straight line is 1800
The value obtained by dividing μm is an average value calculated from the number of cells measured according to JIS K6402.

Thermal conductivity was measured according to JIS at 200 mm square of phenolic resin foam sample, 5 ° C for low temperature plate and 35 ° C for high temperature plate.
It measured according to the plate heat flow meter method of A1412. The density is 2
A phenolic resin foam of 0 cm square was used as a sample, and the weight and apparent volume were measured by removing the face material and the siding material of the sample, and were 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. The confirmation of the foaming agent, the high-boiling aliphatic hydrocarbon or the high-boiling alicyclic hydrocarbon in the phenol resin foam can be performed as follows. 50
A test piece of × 50 × thickness mm is kept in a standard temperature state class 3 (temperature 23 ± 5 ° C.) and a standard humidity state class 3 (relative humidity 40 to 70%) specified in JIS K 7100 for 16 hours or more, and then the surface is measured. Remove the agent and weigh accurately. The test piece is pulverized with a solvent selected from pyridine or toluene or DMF or the like in an airtight container to extract a blowing agent and a high-boiling aliphatic hydrocarbon or a high-boiling alicyclic hydrocarbon or a mixture thereof. Gas chromatography or
Quantify by liquid chromatography. If necessary, the extracted component may be continuously identified by LC-IR (liquid chromatography-infrared absorption spectrometer). Alternatively, the extracted components may be separated and collected by liquid chromatography for collection, and the extracted components may be identified by measuring the IR spectrum or NMR spectrum of each component. The molecular structure of the low-boiling blowing agent or the like may be confirmed by introducing a component separated by gas chromatography into a mass spectrometer.

[0027]

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 was added to another reactor.
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 liquid 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 Resole Resin A reactor was charged with 4350 g of 37% formalin and 3000 g of 99% phenol, and stirred with a propeller rotary 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 was kept at 50 ° C 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.

[0030]

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, 94.7% by weight of isopentane (manufactured by Wako Pure Chemical Industries, purity: 99% or more) as a foaming agent, and 5% by weight of paraffin (manufactured by Wako Pure Chemical Industries, melting point: 44 ° C. to 46 ° C., primary reagent) %, 0.3% by weight of nitrogen 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 mold frame laid with Spunbond E1040 (non-woven fabric manufactured by Asahi Chemical Industry Co., Ltd.), placed in an oven at 80 ° C. and kept for 5 hours to produce a phenolic resin foam.

[0031]

Example 2 Example 1 except that the blowing agent was changed to a mixture of 79.7% by weight of isopentane, 20.0% by weight of paraffin, and 0.3% by weight of nitrogen, and the amount of the blowing agent was changed to 8.5 parts by weight. A phenolic resin foam was produced in exactly the same manner as described above.

[0032]

Example 3 Example 1 was repeated except that paraffin was dissolved in a resole resin mixture in an amount of 5% by weight based on the resin mixture, and that a mixture of 99.7% by weight of isopentane and 0.3% by weight of nitrogen was used as a blowing agent. A phenolic resin foam was produced in exactly the same way.

[0033]

Example 4 A phenolic resin foam was produced 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, 0.2% by weight of paraffin and 0.3% by weight of nitrogen.

[0034]

Example 5 The procedure was the same 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 92.7% by weight of isopentane, 7% by weight of paraffin, and 0.3% by weight of nitrogen. To produce a phenolic resin foam.

[0035]

Example 6 The blowing agent was changed to a mixture of 89.7% by weight of normal pentane (a special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.), 10% by weight of paraffin, and 0.3% by weight of nitrogen, and the amount of the blowing agent was changed to 7.7. A phenol resin foam was produced in exactly the same manner as in Example 1 except that the amount was changed to parts by weight.

[0036]

Example 7 The foaming 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 paraffin, and 0.3% by weight of nitrogen. A phenol resin foam was produced in exactly the same manner as in Example 1 except that the amount was changed to parts by weight.

[0037]

Example 8 The blowing agent was changed to a mixture of 98.7% by weight of isobutane (SK Corporation, purity: 99% or more), 1% by weight of paraffin, and 0.3% by weight of nitrogen, and the amount of the blowing agent was 5 parts by weight. A phenol resin foam was produced in exactly the same manner as in Example 1 except that the phenolic resin foam was changed.

[0038]

Example 9 The procedure was the same as in Example 1 except that the blowing agent was changed to a mixture of 94.7% by weight of isopentane, 5% by weight of liquid paraffin (a first-class reagent manufactured by Wako Pure Chemical Industries, Ltd.) and 0.3% by weight of nitrogen. To produce a phenolic resin foam.

[0039]

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

[0040]

Comparative Example 1 Example 1 was repeated except that paraffin was dissolved in a resole resin mixture at 15% by weight based on the resin mixture, and a mixture of 99.7% by weight of isopentane and 0.3% by weight of nitrogen was used as a blowing agent. A phenolic resin foam was produced in exactly the same way.

[0041]

Comparative Example 2 A phenol resin 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.

[0042]

Comparative Example 3 A phenolic resin foam was produced 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, 0.1% by weight of paraffin and 0.3% by weight of nitrogen.

[0043]

Comparative Example 4 A phenol resin 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.

[0044]

Comparative Example 5 A phenolic resin foam was prepared in exactly 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. In addition, the raw material resin of the phenolic resin foam sample obtained in the above Examples and Comparative Examples, closed cell ratio, average cell diameter, thermal conductivity,
Table 1 summarizes the high boiling point hydrocarbon content, density, brittleness, and compressive strength in the phenolic resin foam.

[0045]

[Table 1]

[0046]

The phenolic resin foam according to the present invention has excellent heat insulating performance, excellent mechanical strength such as compressive strength, and remarkably improved surface brittleness. 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 (4)

[Claims] The foaming agent is a hydrocarbon having a low boiling point, a closed cell ratio of 80% or more, and an average cell diameter of 10 μm to 400 μm.
A phenolic resin foam having a thermal conductivity of not more than 0.025 kcal / mhr ° C, wherein the phenolic resin foam comprises a high-boiling aliphatic hydrocarbon, a high-boiling alicyclic hydrocarbon, or a mixture thereof. A phenolic resin foam containing 0.01 to 10% by weight based on the foam. 2. The foaming agent according to claim 1, wherein the foaming agent has 4 to 6 carbon atoms.
The phenolic resin foam according to claim 1, which is a saturated hydrocarbon. 3. The density is 10 kg / m ³ or more and 70 kg / m ^3.
Or less, brittleness is 30% or less, and compressive strength is 0.5 k
g / cm ² or more.
The phenolic resin foam as described. 4. The blowing agent is a low-boiling hydrocarbon containing from 0.2 to 50% by weight, based on the blowing agent, of a high-boiling aliphatic hydrocarbon or a high-boiling alicyclic hydrocarbon or a mixture thereof. The phenolic resin foam according to claim 1, 2 or 3, wherein: