JP2016180103A - Phenolic resin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phenolic resin foam which has improved heat insulation properties.SOLUTION: There is provided a phenolic resin foam containing a phenol resin, a foaming agent and a surfactant, where an average cell diameter is 100 μm or less, a density is 10-100 kg/mand a pH is 3 or more and less than 7, the foaming agent contains hydrocarbon and halogenated unsaturated hydrocarbon, and a mass ratio between the hydrocarbon and the halogenated unsaturated hydrocarbon is 9.5:0.5 to 5:5.SELECTED DRAWING: None

Description

  The present invention relates to a phenol resin foam.

The phenol resin foam is excellent in flame retardancy, heat resistance, chemical resistance, corrosion resistance, and the like, and thus has been adopted in various fields as a heat insulating material. For example, in the building field, a phenol resin foam wallboard is employed as a synthetic resin building material, particularly a wallboard interior material.
The phenol resin foam is usually produced by foaming and curing a foamable phenol resin composition containing a phenol resin, a foaming agent, an acid catalyst (curing agent), a surfactant and the like. The phenol resin foam thus produced has closed cells, and the closed cells contain a gas generated from the blowing agent.
Known foaming agents used for phenolic resin foams include hydrocarbons such as butane and pentane (for example, Patent Document 1), and fluorinated unsaturated hydrocarbons such as difluoropropene (for example, Patent Document 2). .

Japanese Patent No. 3813062 Special table 2008-546892 gazette

However, the phenol resin foam is required to further improve the heat insulation.
Then, this invention aims at the phenol resin foam which has the more excellent heat insulation.

In general, halogenated unsaturated hydrocarbons such as fluorinated unsaturated hydrocarbons have lower thermal conductivity than hydrocarbons. For this reason, it was anticipated that the heat insulation property of a phenol resin foam could be improved by using a halogenated unsaturated hydrocarbon as a foaming agent.
However, as a result of investigations by the present inventors, it was not possible to sufficiently foam the foamable phenolic resin composition simply by using a halogenated unsaturated hydrocarbon as a foaming agent.
As a result of further intensive studies, the present inventors have found that when a hydrocarbon and a halogenated unsaturated hydrocarbon are used in combination, the foamable phenol resin composition can be sufficiently foamed and the heat insulation of the phenol resin foam can be further improved. As a result, the present invention has been found.

The present invention has the following aspects.
[1] A phenol resin foam comprising a phenol resin, a foaming agent, and a surfactant,
The average cell diameter is 100 μm or less,
The density is 10 to 100 kg / m ³ ,
pH is 3 or more and less than 7,
The blowing agent has both a hydrocarbon and a halogenated unsaturated hydrocarbon,
The phenol resin foam whose mass ratio of the said hydrocarbon and the said halogenated unsaturated hydrocarbon is hydrocarbon: halogenated unsaturated hydrocarbon = 9.5: 0.5-5: 5.
[2] The phenol resin foam according to [1], wherein the surfactant is at least one surfactant selected from the group consisting of a castor oil alkylene oxide adduct and a silicone surfactant.

  According to the phenol resin foam of this invention, it has the more excellent heat insulation.

The phenol resin foam of the present invention is obtained by foaming and curing a foamable phenol resin composition containing a phenol resin, a foaming agent, an acid catalyst, and a surfactant.
The foamable phenol resin composition may further contain other components other than the phenol resin, the foaming agent, the acid catalyst, and the surfactant, as necessary, as long as the effects of the present invention are not impaired.

(Phenolic resin)
As the phenol resin, a resol type resin is used.
The resol type phenol resin is a phenol resin obtained by reacting a phenol compound and an aldehyde in the presence of an alkali catalyst.
Examples of the phenol compound include phenol, cresol, xylenol, paraalkylphenol, paraphenylphenol, resorcinol, and modified products thereof.
Examples of aldehydes include formaldehyde, paraformaldehyde, furfural, and acetaldehyde.
Examples of the alkali catalyst include sodium hydroxide, potassium hydroxide, calcium hydroxide, aliphatic amine (trimethylamine, triethylamine, etc.) and the like. However, the phenol compound, the aldehyde, and the alkali catalyst are not limited to those described above.
The ratio of a phenol compound and an aldehyde is not specifically limited. Preferably, the molar ratio of phenol compound: aldehyde is 1: 1 to 1: 3, more preferably 1: 1.3 to 1: 2.5.

(Foaming agent)
The blowing agent has both a hydrocarbon and a halogenated unsaturated hydrocarbon.
By using a hydrocarbon and a halogenated unsaturated hydrocarbon together as a foaming agent, the average cell diameter of closed cells in the phenol resin foam is smaller than when only hydrocarbons are used, and the resulting foam is The thermal conductivity is also lowered, and a product with excellent heat insulation is obtained.

As a hydrocarbon, a well-known thing can be used as a foaming agent, and a thing with a boiling point of -20-100 degreeC is used suitably.
The hydrocarbon preferably has a cyclic molecular structure having 4 to 6 carbon atoms or a chain molecular structure having 4 to 6 carbon atoms. For example, isobutane, normal butane, cyclobutane, normal pentane, isopentane, cyclopentane, neopentane. Etc. These hydrocarbons may be used alone or in combination of two or more. These hydrocarbons can ensure excellent heat insulation performance in a wide temperature range from a low temperature region (for example, a heat insulating material for a freezer at about −80 ° C.) to a high temperature region (for example, a heat insulating material for a heating body of about 200 ° C.), It is relatively inexpensive and economically advantageous.

The halogenated unsaturated hydrocarbon has a double bond and a halogen atom in the molecule.
Examples of the halogenated unsaturated hydrocarbon include fluorinated hydrocarbon, chlorinated hydrocarbon, chlorinated fluorinated hydrocarbon, brominated fluorinated unsaturated hydrocarbon, iodinated fluorinated unsaturated hydrocarbon, and the like.
As a halogenated unsaturated hydrocarbon, a well-known thing can be used as a foaming agent, and a thing with a boiling point of -28-80 degreeC is mentioned typically.
The thermal conductivity of the halogenated unsaturated hydrocarbon is preferably 0.013 W / m · K or less, and more preferably 0.011 W / m · K or less.
2-6 are preferable and, as for carbon number of a halogenated unsaturated hydrocarbon, 2-5 are more preferable.

As the halogenated unsaturated hydrocarbon, those known as blowing agents can be used, and fluorinated unsaturated hydrocarbons and chlorinated unsaturated hydrocarbons having a double bond and a halogen atom in the molecule. Brominated fluorinated unsaturated hydrocarbons and the like. Among them, as the halogenated unsaturated hydrocarbon, those having a fluorine atom such as fluorinated unsaturated hydrocarbon and chlorinated fluorinated unsaturated hydrocarbon are preferable. The halogenated unsaturated hydrocarbon may be one in which all of hydrogen is substituted with halogen, or one in which a part of hydrogen is substituted with halogen.
These halogenated unsaturated hydrocarbons may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the fluorinated unsaturated hydrocarbon include hydrofluoroolefins (hereinafter also referred to as “HFO”) having fluorine and a double bond in the molecule. Examples of HFO include 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO-1234ze) (E and Z isomers), 1,1 , 1,4,4,4-hexafluoro-2-butene (HFO1336mzz) (E and Z isomers) (manufactured by SynQuest Laboratories, product number: 1300-3-Z6), etc. Disclosed in (1).
These fluorinated unsaturated hydrocarbons may be used alone or in combination of two or more.

Chlorinated fluorinated unsaturated hydrocarbons include 1,2-dichloro-1,2-difluoroethene (E and Z isomers), 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) ( E and Z isomers) (HoneyWell, trade name: SOLSTICE
LBA), 1-chloro-2,3,3-trifluoropropene (HCFO-1233yd) (E and Z isomers), 1-chloro-1,3,3-trifluoropropene (HCFO-1233zb) (E and Z isomer), 2-chloro-1,3,3-trifluoropropene (HCFO-1233xe) (E and Z isomers), 2-chloro-2,2,3-trifluoropropene (HCFO-1233xc), 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) (manufactured by SynQuest Laboratories, product number: 1300-7-09), 3-chloro-1,2,3-trifluoropropene (HCFO- 1233ye) (E and Z isomers), 3-chloro-1,1,2-trifluoropropene (HCFO-1233yc), 3 , 3-dichloro-3-fluoropropene, 1,2-dichloro-3,3,3-trifluoropropene (HCFO-1223xd) (E and Z isomers), 2-chloro-1,1,1,4 4,4-hexafluoro-2-butene (E and Z isomers), 2-chloro-1,1,1,3,4,4,4-heptafluoro-2-butene (E and Z variants), etc. Is mentioned.
These chlorinated fluorinated unsaturated hydrocarbons may be used alone or in combination of two or more.

  The content of the foaming agent in the foamable phenol resin composition is preferably 1 to 20 parts by mass, more preferably 3 to 15 parts by mass, and still more preferably 5 to 12 parts by mass per 100 parts by mass of the phenol resin. If it is less than the said lower limit, the foaming degree of a foamable phenol resin composition may become inadequate, and there exists a possibility that the heat insulation of a phenol resin foam may fall. If the value exceeds the upper limit, the foaming phenol resin composition may be excessively foamed and the strength of the phenol resin foam may be reduced.

  The mass ratio of hydrocarbon to halogenated unsaturated hydrocarbon in the blowing agent is hydrocarbon: halogenated unsaturated hydrocarbon = 9.5: 0.5 to 5: 5, 9: 1 to 6: 4 being Preferably, 9: 1 to 7: 3 are more preferable. When the proportion of the halogenated unsaturated hydrocarbon is equal to or higher than the lower limit, the heat insulating property of the phenol resin foam can be further improved. If the ratio of the halogenated unsaturated hydrocarbon is not more than the above upper limit value, the foamable phenol resin composition can be sufficiently foamed. Since halogenated unsaturated hydrocarbons are highly compatible with phenolic resins, when the proportion of halogenated unsaturated hydrocarbons exceeds the above upper limit, the viscosity of the phenolic resin composition decreases and foaming of the phenolic resin composition does not occur. It will be enough.

  When the foaming agent is a mixture of two or more foaming agents, the composition (mass ratio) of the foaming agent contained in the foamable phenol resin composition is the composition of the foaming agent contained in the foam-cured phenol resin foam. The compositions of the two or more halogenated hydrocarbons contained in the phenol resin foam can be confirmed by, for example, the following solvent extraction method.

Solvent extraction method:
Using a standard gas of halogenated hydrocarbon, the retention time under the following measurement conditions with a gas chromatograph-mass spectrometer (GC / MS) is obtained in advance. Next, 1.6 g of a phenol resin foam sample from which the upper and lower face materials have been peeled is taken into a glass container for grinding, and 80 mL of tetrahydrofuran (THF) is added. After crushing the sample so that it is immersed in the solvent, it is pulverized and extracted for 1 minute and 30 seconds with a homogenizer, the extract is filtered with a membrane filter having a pore size of 0.45 μm, and the filtrate is subjected to GC / MS. The type of halogenated unsaturated hydrocarbon is identified from the retention time and mass spectrum determined in advance. In addition, other types of halogenated hydrocarbons are identified by retention time and mass spectrum. The detection sensitivity of each blowing agent component is measured with a standard gas, and the composition (mass ratio) is calculated from the detection area area and detection sensitivity of each gas component obtained by the GC / MS.
GC / MS measurement conditions Column used: DB-5ms (Agilent Technology) 60m, inner diameter 0.25mm, film thickness 1μm
Column temperature: 40 ° C (10 minutes)-10 ° C / min-200 ° C
Inlet temperature: 200 ° C
Interface temperature: 230 ° C
Carrier gas: He 1.0 mL / min Split ratio: 20: 1
Measuring method: scanning method m / Z = 11 to 550

(Acid catalyst)
The acid catalyst is used to initiate the polymerization of the phenolic resin.
Examples of the acid catalyst include organic acids such as benzenesulfonic acid, ethylbenzenesulfonic acid, paratoluenesulfonic acid, xylenesulfonic acid, naphthalenesulfonic acid, and phenolsulfonic acid, and inorganic acids such as sulfuric acid and phosphoric acid. These acid catalysts may be used singly or in combination of two or more.

  The content of the acid catalyst in the foamable phenol resin composition is preferably 5 to 30 parts by mass, more preferably 8 to 25 parts by mass, and still more preferably 10 to 20 parts by mass per 100 parts by mass of the phenol resin.

(Surfactant)
The surfactant contributes to the refinement of the cell diameter (cell diameter).
The surfactant is not particularly limited, and those known as foam stabilizers can be used. For example, castor oil alkylene oxide adduct, silicone surfactant, polyoxyethylene sorbitan fatty acid ester and the like can be mentioned. These surfactants may be used singly or in combination of two or more.
The surfactant preferably contains one or both of a castor oil alkylene oxide adduct and a silicone-based surfactant because it is easy to form bubbles having a small cell diameter, and has a lower thermal conductivity and flame retardancy. It is more preferable that a silicone-based surfactant is included in that it can be made higher.

The alkylene oxide in the castor oil alkylene oxide adduct is preferably an alkylene oxide having 2 to 4 carbon atoms, more preferably ethylene oxide (hereinafter abbreviated as “EO”) or propylene oxide (hereinafter abbreviated as “PO”). Preferably, EO is more preferable. The alkylene oxide added to the castor oil may be one type or two or more types.
As the castor oil alkylene oxide adduct, castor oil EO adduct and castor oil PO adduct are preferable.

  The number of moles of alkylene oxide added in the castor oil alkylene oxide adduct is preferably more than 20 moles and less than 60 moles, more preferably 21 to 40 moles per mole of castor oil. In such a castor oil alkylene oxide adduct, a polyoxyalkylene group (polyoxyethylene group or the like) formed by a hydrophobic group mainly composed of a long-chain hydrocarbon group of castor oil and a predetermined addition mole of alkylene oxide (EO or the like) The hydrophilic group mainly composed of is arranged in a well-balanced manner in the molecule and exhibits a good surface activity. For this reason, the bubble diameter of a phenol resin foam becomes small. Moreover, a softness | flexibility is provided to the cell wall of a phenol resin foam, and generation | occurrence | production of a crack is prevented.

Examples of the silicone surfactant include a copolymer of dimethylpolysiloxane and polyether, and an organopolysiloxane compound such as octamethylcyclotetrasiloxane. Among them, a copolymer of dimethylpolysiloxane and polyether is preferable in that more uniform and finer bubbles can be obtained.
The structure of the copolymer of dimethylpolysiloxane and polyether is not particularly limited. For example, an ABA type in which polyether chains are bonded to both ends of the siloxane chain, and a plurality of siloxane chains and a plurality of polyether chains are alternated. (AB) n-type bonded to, branched type in which a polyether chain is bonded to each end of a branched siloxane chain, and a polyether chain bonded to the siloxane chain as a side group (group bonded to a portion other than the terminal) A pendant type etc. are mentioned.

Examples of the copolymer of dimethylpolysiloxane and polyether include dimethylpolysiloxane-polyoxyalkylene copolymer.
As for carbon number of the oxyalkylene group in polyoxyalkylene, 2 or 3 is preferable. The oxyalkylene group constituting the polyoxyalkylene may be one type or two or more types.
Specific examples of the dimethylpolysiloxane-polyoxyalkylene copolymer include dimethylpolysiloxane-polyoxyethylene copolymer, dimethylpolysiloxane-polyoxypropylene copolymer, dimethylpolysiloxane-polyoxyethylene-polyoxypropylene copolymer. A polymer etc. are mentioned.

  As the copolymer of dimethylpolysiloxane and polyether, those having a polyether chain whose terminal is -OR (wherein R is a hydrogen atom or an alkyl group) are preferred, and the thermal conductivity is more favorable. In view of reduction, it is particularly preferable that R is a hydrogen atom.

The content of the surfactant in the foamable phenol resin composition is preferably 1 to 10 parts by mass and more preferably 2 to 5 parts by mass per 100 parts by mass of the phenol resin. If the content of the surfactant is not less than the above lower limit value, the bubble diameter tends to be uniform and fine. If it is below the said upper limit, the water absorption of a phenol resin foam will become low and manufacturing cost will also be suppressed.
In the foamable phenol resin composition, the mass ratio represented by the foaming agent: surfactant is preferably, for example, 1: 1 to 6: 1. If the mass ratio of the foaming agent and the surfactant is within the above range, the foaming agent can be uniformly dispersed in the phenol resin to form fine bubbles. If the ratio of the foaming agent is less than the above lower limit, the content of the foaming agent in the foamable phenol resin composition becomes too small, and foaming of the foamable phenol resin composition may be insufficient. When the ratio of the foaming agent exceeds the above upper limit, the amount of the surfactant becomes too small, and the dispersibility of the foaming agent in the foamable phenol resin composition may be lowered.

  About the kind of surfactant contained in the phenol resin foam, gas chromatograph-mass spectrometer (GC / MS), liquid chromatograph-mass spectrometer (LC / MS), etc. are selected according to the kind. In particular, for silicone surfactants, the presence or absence of silicone surfactants is confirmed by confirming the presence or absence of Si (silicon) by inductively coupled plasma emission spectroscopy (ICP emission spectroscopy). And the concentration can be calculated.

<Measurement of phenol resin foam by ICP emission spectroscopy>
About 0.02 to 0.05 g of a sample is taken from a central portion in the thickness direction of the phenol resin foam in a platinum crucible, and the mass of the detailed sample is precisely weighed. Next, 0.5 g ± 0.1 g of sodium carbonate was added to the platinum crucible containing the sample and melted under the following ashing and melting conditions. After cooling the melt, the melt in the platinum crucible is dissolved in pure water, transferred to a 50 ml volumetric flask, and made up to 50 ml with pure water to prepare a sample solution.
The sample solution is measured under the following ICP measurement conditions, and the Si content in the sample solution is calculated from the calibration curve.
And the density | concentration (microgram / g) of Si in a phenol resin foam was computed from the following formula.
[Si concentration in phenol resin foam (μg / g) = Si concentration in sample solution (μg / mL) × 50 (mL) / mass of accurately weighed sample (g)]
<Ashing / melting procedure>
The platinum crucible containing the sample is heated for about 15 minutes in a muffle furnace set at 350 ° C. and dried. Next, the muffle furnace is heated to 650 ° C. and heated for about 3 hours, further heated to 800 ° C. and heated for about 1 hour to ash the sample. Next, the muffle furnace is heated to 910 ° C. and heated for about 1 hour to melt the sample and sodium carbonate.
<ICP measurement conditions>
Measuring device: SII nanotechnology SPS5100
Measuring element: Si (wavelength: 288.158 nm)
High frequency output: 1.2 kW
Carrier gas flow rate: 0.9 L / min
Plasma flow rate: 15 L / min
Auxiliary flow rate: 1.5 L / min
<How to create a calibration curve>
Dilute pure water only blank (0ppm) and standard solution for calibration curve (product name: silicon standard solution manufactured by Wako Pure Chemical Industries, Ltd.) as standard sample to 0.5ppm, 2ppm, 20ppm, 50ppm Adjust to obtain the Si wavelength peak intensity. The concentration and peak intensity of the blank and the standard sample are plotted to obtain an approximate curve (straight line or quadratic curve) by the least square method, and this is used as a calibration curve for quantification.

  If the Si concentration (μg / g) in the sample of the phenol resin foam thus measured is 100 μg / g (100 ppm) or more, it can be determined that the silicone-based surfactant is contained. The Si concentration (μg / g) to be measured depends on the amount and type of the silicone surfactant used, but is preferably such an amount that the Si concentration is 100 μg / g or more and 3000 or less.

(Other ingredients)
The foamable phenol resin composition may contain components (arbitrary components) other than the phenol resin, the foaming agent, the acid catalyst, and the surfactant. Examples of optional components include a foam nucleating agent, urea, a filler (filler), a plasticizer, a crosslinking agent, an organic solvent, an amino group-containing organic compound, and a colorant.

Examples of the foam nucleating agent include low-boiling substances such as nitrogen, helium, argon, and air. By using the foam nucleating agent, the bubbles in the phenol resin foam can be made more uniform and fine.
The content of the foam nucleating agent in the foamable phenolic resin composition is preferably 0.05 to 5 mol% with respect to the foaming agent.
However, the foam nucleating agent is usually dispersed in advance in the foaming agent and blended in the foamable phenolic resin composition. In order to disperse the foam nucleating agent in the foaming agent, it is necessary to inject the foam nucleating agent into the foaming agent under a pressurized condition, and the manufacturing process becomes complicated. Since the present invention can form uniform and fine bubbles without using a foam nucleating agent, it does not require equipment or a complicated process for dispersing the foam nucleating agent in the foaming agent, and easily produces a phenol resin foam. it can.

  Urea is used as a formaldehyde catcher agent that traps formaldehyde when foaming a foamable phenolic resin composition to produce a foam.

As the filler, an inorganic filler is preferable in that a phenol resin foam having low thermal conductivity and acidity and improved fire resistance can be obtained.
Examples of the inorganic filler include metal hydroxides and oxides of metals such as aluminum hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, aluminum oxide, zinc oxide, titanium oxide, and antimony oxide, and metal powders such as zinc; Metal carbonates such as calcium, magnesium carbonate, barium carbonate, zinc carbonate; alkali metal hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate; alkaline earth metal hydrogen carbonates such as calcium hydrogen carbonate and magnesium hydrogen carbonate; sulfuric acid Examples include calcium, barium sulfate, calcium silicate, mica, talc, bentonite, zeolite, silica gel, and the like. However, when a strong acid is used as the acid catalyst, it is necessary to add the metal powder and carbonate within a range that does not affect the adjustment of pot life. These inorganic fillers may be used alone or in combination of two or more.

  The content of the filler in the foamable phenolic resin composition is preferably such that the pH is 3 or more and less than 7, more preferably 4 or more and less than 6, and most preferably 5 or more and less than 6. For example, the content of the filler is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, further preferably 3 to 15 parts by mass, and more preferably 5 to 10 parts by mass per 100 parts by mass of the phenol resin. Particularly preferred. If content of a filler is less than the said lower limit, pH of a phenol resin foam will become low. When the pH is lowered, the acidity increases, so that the material in contact with the phenol resin foam may be corroded. When the filler content exceeds the above upper limit value or the pH is 7 or more, the curing reaction by the acid catalyst is remarkably inhibited, and the productivity may be lowered.

Moreover, you may neutralize the residual acidic content of a phenol resin foam by making the shape | molded phenol resin foam cure in the atmosphere of an alkaline volatile matter.
The curing atmosphere needs to be an atmosphere of alkaline volatiles. The alkaline volatiles are not particularly limited as long as they are alkaline volatiles, and examples thereof include alkanolamine and ammonia. Ammonia is preferred for cost and safety reasons.
The concentration of the alkaline volatiles atmosphere is preferably 3% by mass or more as the initial concentration, although it depends on the type of the alkaline volatiles. If it is 3% by mass or less, the effect of curing may not be sufficiently observed, which is not preferable.
In such an atmosphere, the curing is preferably performed so that the pH is 3 or more and less than 7, more preferably 4 or more and less than 6, and most preferably 5 or more and less than 6. When the pH is 7 or more, the phenol resin foam or face material has an ammonia odor, which is not preferable.
Specifically, as an example, 30 foams with a width of 910 mm, a length of 1820 mm, and a thickness of 20 mm are stacked in a curing chamber with a volume of 7.5 m ³ with a 30 mm spacer interposed therebetween, and 25% ammonia water The preferred concentration can be achieved (8.8% by weight as the initial concentration) by sealing together about 2 L together in a separate container.

  The filler also functions as a protective agent that captures hydrogen fluoride. It is known that the halogenated unsaturated hydrocarbon used as the blowing agent generates hydrogen fluoride by decomposition or contains hydrogen fluoride used as a raw material for its production as an impurity (see Table 2014). 511930). This hydrogen fluoride reacts with the siloxane bond constituting the hydrophobic part of the silicone-based surfactant to reduce the surface active action. Then, the said filler may be added to a foamable phenol resin composition as a protective agent.

(Method for producing foamable phenolic resin composition)
The foamable phenol resin composition is prepared by mixing a phenol resin, a foaming agent, an acid catalyst, a surfactant, and optional components as necessary.
The order of mixing the respective components is not particularly limited. For example, a surfactant and, if necessary, optional components are added to and mixed with a phenol resin, and a foaming agent and an acid catalyst are added to the resulting mixture. A foamable phenolic resin composition is prepared by supplying to a mixer and stirring.

(Method for producing phenolic resin foam)
The phenolic resin foam of the present invention can be produced by foaming and curing the foamable phenolic resin composition.
A phenol resin foam is manufactured by a well-known manufacturing method. For example, the foamable phenol resin composition can be put into an arbitrary mold and the foamable phenol resin composition in the mold can be heated at 30 to 95 ° C. to produce a phenol resin foam.

When producing a phenolic resin foam by foam molding, a face material may be provided.
The face material is not particularly limited, and is at least one selected from a glass fiber nonwoven fabric, a spunbond nonwoven fabric, an aluminum foil-clad nonwoven fabric, a metal plate, a metal foil, a plywood, a calcium silicate plate, a gypsum board, and a wood cement board. Is preferred.
The face material may be provided on one side of the phenol resin foam or may be provided on both sides. When provided on both sides, each face material may be the same or different.
As a method of providing a face material when producing a phenolic resin foam, for example, a face material is disposed on a conveyor belt that continuously runs, and a foamable phenol resin composition is discharged onto the face material, on which the face material is disposed. After laminating other face materials, a method of foaming by passing through a heating furnace can be mentioned. Thereby, the phenol resin foam with a face material which face material laminated | stacked on both surfaces of the sheet-like phenol resin foam is obtained.
After the foam molding, the face material may be provided by being bonded to the phenol resin foam using an adhesive.

In the phenol resin foam of the present invention, a plurality of bubbles are formed, the bubble wall is substantially free of pores, and at least some of the plurality of bubbles are closed cells that are not in communication with each other. It has become. In the closed cells, hydrocarbon gas and halogenated unsaturated hydrocarbon gas used as a blowing agent are held. The closed cell ratio is usually 85% or more, and more preferably 90% or more.
The closed cell ratio is measured according to JIS K7138-2006.

  The average cell diameter in the phenol resin foam of the present invention is 100 μm or less, preferably 80 μm or less, and more preferably 70 μm or less. 40 μm or more is preferable, and 50 μm or more is more preferable. When the average cell diameter is 100 μm or less, convection and radiation within the cell are suppressed, the thermal conductivity of the phenol resin foam is lowered, and the heat insulation of the phenol resin foam can be further improved.

  The average cell diameter of the phenol resin foam is the type of foaming agent and the ratio of phenol and formaldehyde in the synthesis of the resole resin, the amount of curing agent (resin curing rate, degree of crosslinking, elongation viscosity after crosslinking); It is adjusted depending on the type of surfactant, foaming conditions (heating temperature, heating time, etc.) and the like. For example, if the mass ratio of hydrocarbon to halogenated unsaturated hydrocarbon is within the range of the present invention, the average cell diameter can be reduced and a foam having low thermal conductivity can be obtained.

The density of the phenol resin foam is not particularly limited, but 10 to 100 kg / ^{m 3,} preferably ^{20~40kg / m 3, 25~35kg / m} 3 and more preferably. If it is more than the said lower limit, it will be easy to aim at the further improvement of the intensity | strength of a phenol resin foam, and if it is below the said upper limit, it will be easy to aim at the further improvement of the heat insulation of a phenol resin foam.
The brittleness (JIS A 9511: 2003) of the phenol resin foam is preferably 20% or less, more preferably 10 to 18%.

The pH of the phenol resin foam is 3 or more and less than 7, preferably 4 or more and less than 7, and more preferably 5 or more and less than 7.
The pH is measured by the following method. A phenol resin foam is pulverized in a mortar to 250 μm (60 mesh) or less to prepare a sample. Weigh 0.5 g of sample into a 200 mL Erlenmeyer flask with a stopper. Add 100 mL of pure water to a conical stoppered Erlenmeyer flask and seal tightly. Using a magnetic stirrer, the inside of the conical stoppered flask is stirred at 23 ° C. ± 5 ° C. for 7 days to obtain a sample solution. The pH of the obtained sample solution is measured with a pH meter, and the value is defined as pH.

The thermal conductivity of the phenol resin foam is preferably 0.022 W / m · K or less, more preferably 0.021 W / m · K or less, and further preferably 0.020 W / m · K or less. If the thermal conductivity is 0.022 W / m · K or less, even if the thickness of the foam is reduced, the heat insulating property is excellent, so that the heat insulating material layer can be made thinner. In addition, as thickness of a heat insulating material, 20 mm or more and 160 mm or less are preferable.
The average cell diameter and closed cell ratio contribute greatly to the thermal conductivity of the phenol resin foam, but the type and composition of the foaming agent; the ratio of phenol to formalin in the synthesis of the resole resin, the amount of curing agent (resin content) Curing speed, degree of crosslinking, elongation viscosity after crosslinking) can be adjusted according to the type of surfactant. For example, as described above, the smaller the average cell diameter, the lower the thermal conductivity of the phenol resin foam. Further, when the surfactant is a silicone-based surfactant, particularly one having a polyether chain having a —OH end, the thermal conductivity tends to be lower than when other surfactants are used.

  As above-mentioned, the phenol resin foam of this embodiment is excellent by heat insulation by using a specific foaming agent. For this reason, the phenol resin foam of this embodiment is particularly useful as a heat insulating material for buildings that require high heat insulating properties such as apartment houses, built houses, and warehouses.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

(Measuring method)
The measuring methods used in Examples and Comparative Examples described later are shown below.
<Average bubble diameter>
A test piece was cut out from approximately the center in the thickness direction of the phenol resin foam. The cut surface in the thickness direction of the test piece was photographed at 50 times magnification. Four straight lines 9 cm in length were drawn on the photographed image. At this time, a straight line was drawn so as to avoid voids (voids of 2 mm 2 or more). The number of bubbles crossed by each straight line (the number of cells measured according to JIS K6400-1: 2004) was counted for each straight line, and the average value per straight line was obtained. 1800 μm was divided by the average value of the number of bubbles, and the obtained value was defined as the average cell diameter.

<Density>
It measured according to JIS A 9511: 2009.

<PH>
A phenol resin foam was pulverized to 250 μm (60 mesh) or less in a mortar to prepare a sample. 0.5 g of sample was weighed into a 200 mL conical stoppered flask. 100 mL of pure water was added to a conical stoppered Erlenmeyer flask and sealed. Using a magnetic stirrer, the inside of the conical stoppered Erlenmeyer flask was stirred at 23 ° C. ± 5 ° C. for 7 days to prepare a sample solution. The pH of the obtained sample solution was measured with a pH meter, and the value was defined as pH.

<Thermal conductivity>
Based on JIS A 9511: 2009, the thermal conductivity of the phenol resin foam was measured. The same sample was measured twice and the average value was obtained.

(Examples 1-9, Comparative Examples 1-7)
100 parts by mass of liquid resol type phenolic resin (Asahi Organic Materials Co., Ltd., trade name: PF-339) and surfactant (silicone surfactant, “Part No. SH193” manufactured by Toray Dow Corning, polyether chain Terminal: -OH) 4 parts by mass and formaldehyde catcher agent (urea) 4 parts by mass were mixed and allowed to stand at 20 ° C for 8 hours.
108 parts by mass of the obtained mixture, 10.5 parts by mass of a foaming agent having the composition shown in Table 1, and 15.0 parts by mass of an acid catalyst (a mixture of paratoluenesulfonic acid and xylenesulfonic acid) were mixed to obtain a foamable phenol. A resin composition was prepared.
This foamable phenolic resin composition was placed in a 300 mm × 300 mm × 45 mm mold and heated for 300 seconds in a dryer at 70 ° C. for foam molding. Thereafter, the molded product was taken out from the mold, put into a dryer at 85 ° C., cured for 5 hours, and cured to produce a phenol resin foam.
The phenol resin foam obtained above was raised from the floor of the curing warehouse with a 30 mm spacer sandwiched between the bottoms of the foam, and was cured for 24 hours while maintaining the temperature at 40 ° C. or higher. At this time, about 2 L of ammonia water (25%) was sealed in a curing container together with the one put in an individual container.
In the table, “HC” represents a hydrocarbon, and “AH” represents a halogenated unsaturated hydrocarbon.

(Example 10)
A phenolic resin was used in the same manner as in Example 6 except that the end of the polyether chain was -OR (wherein R is an alkyl group) ("Product No. SF2936F" manufactured by Toray Dow Corning). A foam was made.

(Example 11)
A phenol resin foam was produced in the same manner as in Example 6 except that the silicone surfactant was castor oil EO adduct (added mole number: 34).

  About the phenol resin foam of each example, the average bubble diameter and thermal conductivity were measured. However, in Comparative Examples 4 to 7, foaming was insufficient and the molded product was not filled in the mold. For this reason, about Comparative Examples 4-7, thermal conductivity, an average bubble diameter, and pH were not measured. The results are shown in Table 1.

As shown in the above results, in Examples 1 to 11 to which the present invention was applied, the foamable phenol resin composition was sufficiently foamed, and the average cell diameter was as fine as 100 μm or less. In Examples 1 to 11, the thermal conductivity was 0.022 W / m · K or less.
Comparative Examples 1 to 3 using a foaming agent containing only hydrocarbons had a thermal conductivity of more than 0.022 W / m · K.
In Comparative Examples 4 to 7 in which the ratio of the halogenated unsaturated hydrocarbon exceeds the upper limit of the present invention, foaming was insufficient.
From these results, it was confirmed that by applying the present invention, a phenol resin foam having low thermal conductivity (that is, more excellent in heat insulation) can be obtained.

Claims (2)

A phenolic resin foam containing a phenolic resin, a foaming agent, and a surfactant,
The average cell diameter is 100 μm or less,
The density is 10 to 100 kg / m ³ ,
pH is 3 or more and less than 7,
The blowing agent has both a hydrocarbon and a halogenated unsaturated hydrocarbon,
The phenol resin foam whose mass ratio of the said hydrocarbon and the said halogenated unsaturated hydrocarbon is hydrocarbon: halogenated unsaturated hydrocarbon = 9.5: 0.5-5: 5.   The phenol resin foam according to claim 1, wherein the surfactant is at least one surfactant selected from the group consisting of a castor oil alkylene oxide adduct and a silicone surfactant.