JP6791643B2 - Phenolic resin foam - Google Patents

Description

The present invention relates to phenolic resin foams.

Phenolic resin foams are used in various fields as heat insulating materials because they are excellent in flame retardancy, heat resistance, chemical resistance, corrosion resistance and the like. For example, in the construction field, phenolic resin foam wallboards are used as synthetic resin building materials, especially wallboard interior materials.
The phenolic resin foam is usually produced by foaming and curing a foamable phenolic resin composition containing a phenolic resin, a foaming agent, an acid catalyst (curing agent), a surfactant and the like. The phenolic resin foam produced in this manner has closed cells, and the closed cells contain gas generated from the foaming agent.
As the foaming agent used for the phenolic resin foam, hydrocarbons such as butane and pentane (for example, Patent Document 1), fluorinated unsaturated hydrocarbons such as difluoropropene (for example, Patent Document 2) and the like are known. ..

Japanese Patent No. 3813062 Japanese Patent Publication No. 2008-546892

However, the phenolic resin foam is required to have further improved heat insulating properties.
Therefore, an object of the present invention is a phenolic resin foam having better heat insulating properties.

In general, halogenated unsaturated hydrocarbons such as fluorinated unsaturated hydrocarbons have a lower thermal conductivity than hydrocarbons. Therefore, it was expected that the heat insulating property of the phenolic resin foam could be improved by using halongened unsaturated hydrocarbon as a foaming agent.
However, as a result of studies by the present inventors, it was not possible to sufficiently foam the effervescent phenolic resin composition even if the halogenated unsaturated hydrocarbon was simply used as the foaming agent.
As a result of further diligent studies, the present inventors can sufficiently foam the effervescent phenolic resin composition and further enhance the heat insulating property of the phenolic resin foam when the hydrocarbon and the halogenated unsaturated hydrocarbon are used in combination. We found the above findings and came up with the present invention.

The present invention has the following aspects.
[1] 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 ,
The pH is 3 or more and less than 7,
The foaming agent contains both hydrocarbons and halogenated unsaturated hydrocarbons.
A phenolic resin foam having a mass ratio of the hydrocarbon to the halogenated unsaturated hydrocarbon of hydrocarbon: halogenated unsaturated hydrocarbon = 9.5: 0.5 to 5: 5.
[2] The phenolic 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-based surfactant.

According to the phenolic resin foam of the present invention, it has better heat insulating properties.

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

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

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

As the hydrocarbon, a known foaming agent can be used, and a hydrocarbon having a boiling point of -20 to 100 ° C. is preferably used.
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, and for example, isobutane, normal butane, cyclobutane, normal pentane, isopentane, cyclopentane, neopentane. And so on. These hydrocarbons may be used alone or in combination of two or more. These hydrocarbons can ensure excellent heat insulating performance in a wide temperature range from a low temperature range (for example, a heat insulating material for a freezer at about -80 ° C) to a high temperature range (for example, a heat insulating material for a heating body at about 200 ° C). It is relatively inexpensive and economically advantageous.

Halogenated unsaturated hydrocarbons have double bonds and halogen atoms in the molecule.
Examples of the halogenated unsaturated hydrocarbon include fluorinated hydrocarbons, chlorinated hydrocarbons, chlorinated fluorinated hydrocarbons, brominated fluorinated unsaturated hydrocarbons, and iodide fluorinated unsaturated hydrocarbons.
As the halogenated unsaturated hydrocarbon, a known foaming agent can be used, and typically has a boiling point of −28 to 80 ° C.
The thermal conductivity of the halogenated unsaturated hydrocarbon is preferably 0.013 W / m · K or less, more preferably 0.011 W / m · K or less.
The halogenated unsaturated hydrocarbon preferably has 2 to 6 carbon atoms, more preferably 2 to 5 carbon atoms.

As the halogenated unsaturated hydrocarbon, a known foaming agent can be used, and a fluorinated unsaturated hydrocarbon having a double bond and a halogen atom in the molecule and a chlorinated fluorinated unsaturated hydrocarbon , Brominated fluorinated unsaturated hydrocarbons and the like, and among them, as the halogenated unsaturated hydrocarbons, those having a fluorine atom such as fluorinated unsaturated hydrocarbons and chlorinated fluorinated unsaturated hydrocarbons are preferable. The halogenated unsaturated hydrocarbon may be one in which all of hydrogen is substituted with halogen, or one in which part of hydrogen is substituted with halogen.
These halogenated unsaturated hydrocarbons may be used alone or in combination of two or more.

Examples of the fluorinated unsaturated hydrocarbon include hydrofluoroolefins having a fluorine and a double bond in the molecule (hereinafter, also referred to as “HFO”). Examples of the 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., Japanese Patent Publication No. 2009-513812 The ones disclosed in.
These fluorinated unsaturated hydrocarbons may be used alone or in combination of two or more.

Examples of chlorinated fluorinated unsaturated hydrocarbons include 1,2-dichloro-1,2-difluoroethane (E and Z isomers) and 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) (HCFO-1233zd). E and Z isomers) (manufactured by 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), and 2 −Chloro-1,1,1,3,4,4,4-heptafluoro-2-butene (E and Z isomers) and the like can be 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 effervescent phenol resin composition is preferably 1 to 20 parts by mass, more preferably 3 to 15 parts by mass, and even more preferably 5 to 12 parts by mass per 100 parts by mass of the phenol resin. If it is less than the above lower limit, the degree of foaming of the foamable phenolic resin composition may be insufficient, and the heat insulating property of the phenolic resin foam may be lowered. If it exceeds the above upper limit, the degree of foaming of the effervescent phenolic resin composition may be too high, and the strength of the phenolic resin foam may decrease.

The mass ratio of hydrocarbons to halogenated unsaturated hydrocarbons in the foaming agent is hydrocarbon: halogenated unsaturated hydrocarbons = 9.5: 0.5 to 5: 5, and 9: 1 to 6: 4. Preferably, 9: 1 to 7: 3 is more preferable. When the ratio of the halogenated unsaturated hydrocarbon is at least the above lower limit value, the heat insulating property of the phenolic resin foam can be further enhanced. When the ratio of the halogenated unsaturated hydrocarbon is not more than the above upper limit value, the effervescent phenol resin composition can be sufficiently foamed. Since the halogenated unsaturated hydrocarbon has high compatibility with the phenol resin, if the ratio of the halogenated unsaturated hydrocarbon exceeds the above upper limit, the viscosity of the phenol resin composition decreases and the foaming of the phenol resin composition does not occur. Will be enough.

When the foaming agent is a mixture of two or more kinds of 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 composition of two or more types of halogenated hydrocarbons contained in the phenolic resin foam can be confirmed, for example, by the following solvent extraction method.

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

(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 alone or in combination of two or more.

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

(Surfactant)
Surfactants contribute to the miniaturization of bubble diameter (cell diameter).
The surfactant is not particularly limited, and known surfactants and the like can be used. For example, castor oil alkylene oxide adduct, silicone-based surfactant, polyoxyethylene sorbitan fatty acid ester and the like can be mentioned. These surfactants may be used alone or in combination of two or more.
The surfactant preferably contains one or both of the castor oil alkylene oxide adduct and the silicone-based surfactant in that it easily forms bubbles having a small bubble diameter, has a lower thermal conductivity, and is flame-retardant. It is more preferable to include a silicone-based surfactant in that the amount can be increased.

As the alkylene oxide in the castor oil alkylene oxide adduct, alkylene oxide having 2 to 4 carbon atoms is preferable, and ethylene oxide (hereinafter, abbreviated as “EO”) and propylene oxide (hereinafter, abbreviated as “PO”) are more preferable. Preferably, EO is even more preferred. The alkylene oxide added to castor oil may be one kind or two or more kinds.
As the castor oil alkylene oxide adduct, a castor oil EO adduct and a 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 mol and less than 60 mol, more preferably 21 to 40 mol, per 1 mol of castor oil. In such a castor oil alkylene oxide adduct, a polyoxyalkylene group (polyoxyethylene group, etc.) formed by a hydrophobic group mainly composed of a long-chain hydrocarbon group of castor oil and a predetermined addition molar alkylene oxide (EO, etc.) Hydrophilic groups mainly composed of ethylene are arranged in a well-balanced manner in the molecule, and good surface activity is exhibited. Therefore, the bubble diameter of the phenolic resin foam becomes small. In addition, flexibility is imparted to the cell wall of the phenolic resin foam to prevent the occurrence of cracks.

Examples of the silicone-based surfactant include a copolymer of dimethylpolysiloxane and polyether, and an organopolysiloxane-based compound such as octamethylcyclotetrasiloxane. Of these, 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, and for example, ABA type in which a polyether chain is bonded to both ends of a siloxane chain, a plurality of siloxane chains and a plurality of polyether chains are alternated. (AB) n-type bonded to siloxane chain, branched type with a polyether chain bonded to each end of the branched siloxane chain, and a polyether chain bonded to the siloxane chain as a side group (a group bonded to a portion other than the terminal). Examples include a pendant type.

Examples of the copolymer of dimethylpolysiloxane and polyether include a dimethylpolysiloxane-polyoxyalkylene copolymer.
The number of carbon atoms of the oxyalkylene group in the polyoxyalkylene is preferably 2 or 3. The oxyalkylene group constituting the polyoxyalkylene may be one kind or two or more kinds.
Specific examples of the dimethylpolysiloxane-polyoxyalkylene copolymer include a dimethylpolysiloxane-polyoxyethylene copolymer, a dimethylpolysiloxane-polyoxypropylene copolymer, and a dimethylpolysiloxane-polyoxyethylene-polyoxypropylene copolymer. Examples include polymers.

The copolymer of dimethylpolysiloxane and polyether is preferably one having a polyether chain having a terminal -OR (in the formula, R is a hydrogen atom or an alkyl group), and has a higher thermal conductivity. It is particularly preferable that R is a hydrogen atom in that it can be lowered.

The content of the surfactant in the effervescent phenolic resin composition is preferably 1 to 10 parts by mass, more preferably 2 to 5 parts by mass, per 100 parts by mass of the phenol resin. When the content of the surfactant is at least the above lower limit value, the bubble diameter tends to be uniform and fine. If it is not more than the above upper limit, the water absorption of the phenolic resin foam is low, and the manufacturing cost can be suppressed.
In the effervescent phenolic resin composition, the mass ratio represented by the foaming agent: surfactant is preferably, for example, 1: 1 to 6: 1. When 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 may be too small, and the foaming of the foamable phenol resin composition may be insufficient. If the ratio of the foaming agent exceeds the above upper limit, the amount of the surfactant may be too small and the dispersibility of the foaming agent in the foamable phenol resin composition may be lowered.

For the type of surfactant contained in the phenol resin foam, select a gas chromatograph-mass spectrometer (GC / MS), a liquid chromatograph-mass spectrometer (LC / MS), etc. according to the type. However, in particular, for silicone-based surfactants, it is confirmed whether or not silicone-based surfactants are contained by confirming the presence or absence of Si (silicon) by inductively coupled plasma emission spectrometry (ICP emission spectrometry). And the concentration can be calculated.

<Measurement of phenolic resin foam by ICP emission spectroscopy>
Approximately 0.02 to 0.05 g of a sample is collected in a platinum crucible from the central portion of the phenolic resin foam in the thickness direction, 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 the mixture was thawed under the following incineration / melting conditions. After cooling the melt, the melt in the platinum crucible is dissolved in pure water and transferred to a 50 ml volumetric flask, and the volume is adjusted to 50 ml using pure water to prepare a sample solution.
This sample solution is used for measurement under the following ICP measurement conditions, and the Si content in the sample solution is calculated from the calibration curve.
Then, the concentration of Si (μg / g) in the phenolic resin foam was calculated from the following formula.
[Concentration of Si in phenol resin foam (μg / g) = Concentration of Si in sample solution (μg / mL) x 50 (mL) / Mass of precisely weighed sample (g)]
<Procedure for incineration / melting>
The platinum crucible containing the sample is heated in a muffle furnace set at 350 ° C. for about 15 minutes and dried. Next, the muffle furnace is heated to 650 ° C. and heated for about 3 hours, and further heated to 800 ° C. and heated for about 1 hour to incinerate 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: 1.2kW
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>
A blank of pure water only (0 ppm) and a standard solution for calibration curves (product name: silica standard solution manufactured by Wako Pure Chemical Industries, Ltd.) are diluted to 0.5 ppm, 2 ppm, 20 ppm, and 50 ppm. Adjust to obtain the wavelength peak intensity of Si. The concentration and peak intensity of the blank and standard sample are plotted to obtain an approximate curve (straight line or quadratic curve) by the least squares method, and this is used as a calibration curve for quantification.

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

(Other ingredients)
The effervescent phenolic resin composition may contain components (arbitrary components) other than the phenolic resin, the effervescent agent, the acid catalyst and the surfactant. Examples of the optional component include foaming nucleating agent, urea, filler (filler), plasticizer, cross-linking agent, organic solvent, amino group-containing organic compound, colorant and the like.

Examples of the effervescent nucleating agent include low boiling point substances such as nitrogen, helium, argon, and air. By using the foam nucleating agent, the bubbles in the phenolic resin foam can be made more uniform and fine.
The content of the foaming nucleating agent in the effervescent phenolic resin composition is preferably 0.05 to 5 mol% with respect to the effervescent agent.
However, the foaming nucleating agent is usually dispersed in the foaming agent in advance and blended in the foaming phenol resin composition. In order to disperse the foaming nucleating agent in the foaming agent, it is necessary to inject the foaming nucleating agent into the foaming agent under pressurized conditions, which complicates the manufacturing process. Since the present invention can form uniform and fine bubbles without using a foaming nucleating agent, a phenolic resin foam can be easily produced without the need for equipment for dispersing the foaming nucleating agent in the foaming agent or complicated steps. it can.

Urea is used as a formaldehyde catcher agent that traps formaldehyde when foam-molding an effervescent phenolic resin composition to produce a foam.

As the filler, an inorganic filler is preferable in that a phenolic resin foam having low thermal conductivity and acidity and improved fire resistance can be obtained.
Examples of the inorganic filler include 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; carbon dioxide. 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 thereof include calcium, barium sulfate, calcium silicate, mica, talc, bentonite, zeolite, silica gel and the like. However, when a strong acid is used as an acid catalyst, metal powder and carbonate must be added 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 effervescent phenolic resin composition is preferably an amount having a pH of 3 or more and less than 7, more preferably an amount of 4 or more and less than 6, and most preferably an amount of 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 5 to 10 parts by mass per 100 parts by mass of the phenol resin. Especially preferable. If the content of the filler is less than the above lower limit, the pH of the phenolic resin foam becomes low. When the pH is low, the acidity increases, so that the material in contact with the phenolic resin foam may corrode. If the content of the filler exceeds the above upper limit value or the pH is 7 or more, the curing reaction by the acid catalyst may be significantly inhibited and the productivity may be lowered.

Further, the residual acidic content of the phenolic resin foam may be neutralized by curing the molded phenolic resin foam in an atmosphere of an alkaline volatile substance.
The curing atmosphere needs to be an alkaline volatile atmosphere. The alkaline volatile substance is not particularly limited as long as it is an alkaline volatile substance, and examples thereof include alkanolamine and ammonia. Ammonia is preferable for cost and safety reasons.
The concentration of the atmosphere of the alkaline volatile matter depends on the type of the alkaline volatile matter, but the initial concentration is preferably 3% by mass or more. If it is 3% by mass or less, the curing effect may not be sufficiently observed, which is not preferable.
In such an atmosphere, 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 phenolic resin foam and the face material have an ammonia odor, which is not preferable.
Specifically, as an example, in the curing chamber volume 7.5 m ^3, stacked pinching width 910 mm, length 1820Mm, the foam 30 sheets of thickness 20 mm, while the 30mm spacers, 25% aqueous ammonia A preferred concentration can be achieved (initial concentration: 8.8% by weight) by sealing with about 2 L in individual containers.

The filler also functions as a protective agent for capturing hydrogen fluoride. It is known that the halogenated unsaturated hydrocarbon used as a foaming agent generates hydrogen fluoride by decomposition and contains hydrogen fluoride used as a raw material for its production as an impurity (Special Table 2014-). 511930). This hydrogen fluoride reacts with the siloxane bond constituting the hydrophobic portion of the silicone-based surfactant to reduce the surface-active action. Therefore, the filler may be added to the effervescent phenolic resin composition as a protective agent.

(Manufacturing method of effervescent phenolic resin composition)
The effervescent phenolic resin composition is prepared by mixing a phenolic resin, a foaming agent, an acid catalyst, a surfactant and, if necessary, any component.
The mixing order of each component is not particularly limited, but for example, a surfactant and an optional component are added to the phenol resin and mixed, and a foaming agent and an acid catalyst are added to the obtained mixture to obtain this composition. Feed to a mixer and stir to prepare an effervescent phenolic resin composition.

(Manufacturing method of phenolic resin foam)
The phenolic resin foam of the present invention can be produced by foaming and curing the foamable phenolic resin composition.
The phenolic resin foam is produced by a known production method. For example, a phenolic resin foam can be produced by placing the foamable phenolic resin composition in an arbitrary mold and heating the foamable phenolic resin composition in the mold at 30 to 95 ° C.

When the phenolic resin foam is produced by foam molding, a face material may be provided.
The face material is not particularly limited, and is at least one selected from glass fiber non-woven fabric, spunbonded non-woven fabric, aluminum foil-clad non-woven fabric, metal plate, metal foil, plywood, calcium silicate board, gypsum board and wood-based cement board. Is preferable.
The face material may be provided on one side of the phenolic resin foam or 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 phenol resin foam, for example, a face material is arranged on a conveyor belt that runs continuously, a foamable phenol resin composition is discharged on the face material, and the foamable phenol resin composition is discharged on the face material. Examples thereof include a method in which other face materials are laminated and then passed through a heating furnace for foam molding. As a result, a phenolic resin foam with a face material in which face materials are laminated on both sides of the sheet-shaped phenol resin foam can be obtained.
The face material may be provided by being bonded to the phenol resin foam using an adhesive after foam molding.

A plurality of bubbles are formed in the phenolic resin foam of the present invention, there are substantially no pores in the cell wall, and at least a part of the plurality of bubbles is closed cells that are not communicated with each other. It has become. The hydrocarbon used as the foaming agent and the halogenated unsaturated hydrocarbon gas are held in the closed cells. The closed cell ratio is usually 85% or more, more preferably 90% or more.
The closed cell ratio is measured according to JIS K7138-2006.

The average cell diameter in the phenolic 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 in the bubbles are suppressed, the thermal conductivity of the phenolic resin foam is lowered, and the heat insulating property of the phenolic resin foam can be further improved.

The average cell diameter of the phenolic resin foam is the type and composition of the foaming agent, the ratio of phenol to formaldehyde when synthesizing the resole resin, the amount of the curing agent (curing rate of the resin, degree of cross-linking, elongation viscosity after cross-linking); It is adjusted according to the type of surfactant, foaming conditions (heating temperature, heating time, etc.), etc. For example, if the mass ratio of the hydrocarbon to the halogenated unsaturated hydrocarbon is within the range of the present invention, the average cell diameter can be reduced and a foam having a 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. When it is at least the above lower limit value, it is easy to further improve the strength of the phenol resin foam, and when it is at least the above upper limit value, it is easy to further improve the heat insulating property of the phenol resin foam.
The brittleness of the phenolic resin foam (JIS A 9511: 2003) is preferably 20% or less, more preferably 10 to 18%.

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

The thermal conductivity of the phenolic resin foam is preferably 0.022 W / m · K or less, more preferably 0.021 W / m · K or less, and even more preferably 0.020 W / m · K or less. When the thermal conductivity is 0.022 W / m · K or less, the heat insulating property is excellent even if the thickness of the foam is reduced, so that the layer of the heat insulating material can be thinned. The thickness of the heat insulating material is preferably 20 mm or more and 160 mm or less.
The average cell size and closed cell ratio greatly contribute to the thermal conductivity of the phenolic resin foam, but the type and composition of the foaming agent; the ratio of phenol to formalin when synthesizing the resole resin, and the amount of the curing agent (of the resin). Curing rate, degree of cross-linking, elongation viscosity after cross-linking); can be adjusted by the type of surfactant and the like. For example, as described above, the smaller the average cell diameter, the lower the thermal conductivity of the phenolic resin foam tends to be. Further, when the surfactant is a silicone-based surfactant, particularly one having a polyether chain having a −OH terminal, the thermal conductivity tends to be lower than when other surfactants are used.

As described above, the phenolic resin foam of the present embodiment is more excellent in heat insulating property by using a specific foaming agent. Therefore, the phenolic resin foam of the present embodiment is particularly useful as a heat insulating material for buildings such as apartment houses, built houses, and warehouses, which require high heat insulating properties.

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

(Measuring method)
The measurement methods used in Examples and Comparative Examples described later are shown below.
<Average cell diameter>
A test piece was cut out from approximately the center of the phenolic resin foam in the thickness direction. The cut surface in the thickness direction of the test piece was photographed at a magnification of 50 times. Four straight lines with a length of 9 cm were drawn on the captured image. At this time, a straight line was drawn so as to avoid voids (voids of 2 mm2 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 taken as the average cell diameter.

<Density>
Measured according to JIS A 9511: 2009.

<pH>
The phenolic resin foam was pulverized in a mortar to 250 μm (60 mesh) or less to prepare a sample. 0.5 g of the sample was weighed into a 200 mL Erlenmeyer flask with a stopper. 100 mL of pure water was added to an Erlenmeyer flask with a stopper, and the flask was sealed. Using a magnetic stirrer, the inside of the Erlenmeyer flask with a stopper 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 taken as pH.

<Thermal conductivity>
The thermal conductivity of the phenolic resin foam was measured according to JIS A 9511: 2009. The same sample was measured twice, and the average value was calculated.

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

(Example 10)
Phenolic resin in the same manner as in Example 6 except that the end of the polyether chain of the silicone-based surfactant was -OR (in the formula, R is an alkyl group) ("Product No. SF2936F" manufactured by Toray Dow Corning Co., Ltd.). A foam was prepared.

(Example 11)
A phenolic resin foam was produced in the same manner as in Example 6 except that the silicone-based surfactant was castor oil EO adduct (additional number of moles 34).

The average cell diameter and thermal conductivity of the phenolic resin foams of each example were measured. However, in Comparative Examples 4 to 7, the foaming was insufficient and the molded product was not filled in the mold. Therefore, in Comparative Examples 4 to 7, the thermal conductivity, the average cell diameter and the 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 effervescent phenolic resin composition was sufficiently foamed and the average cell diameter was 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 exceeded the upper limit of the present invention, foaming was insufficient.
From these results, it was confirmed that by applying the present invention, a phenolic resin foam having a low thermal conductivity (that is, having better heat insulating properties) can be obtained.

Claims (3)

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 ,
The pH is 3.9 or more and less than 7,
The foaming agent contains both hydrocarbons and halogenated unsaturated hydrocarbons.
The halogenated unsaturated hydrocarbon is selected from the group consisting of 1,1,1,4,4,4-hexafluoro-2-butene (E and Z isomers) and chlorinated fluorinated unsaturated hydrocarbons. At least one species
A phenolic resin foam having a mass ratio of the hydrocarbon to the halogenated unsaturated hydrocarbon of hydrocarbon: halogenated unsaturated hydrocarbon = 9.5: 0.5 to 5: 5. The hydrocarbon is at least one selected from the group consisting of isobutane, normal butane, cyclobutane, normal pentane, isopentane, cyclopentane, and neopentane.
The halogenated unsaturated hydrocarbons are 1,1,1,4,4,4-hexafluoro-2-butene (E and Z isomers) and 1,2-dichloro-1,2-difluoroethane (E and). Z isomer), 1-chloro-3,3,3-trifluoropropene (E and Z isomers), 1-chloro-2,3,3-trifluoropropene (E and Z isomers), 1-chloro -1,3,3-trifluoropropene (E and Z isomers), 2-chloro-1,3,3-trifluoropropene (E and Z isomers), 2-chloro-2,2,3-tri Fluoropropene, 2-chloro-3,3,3-trifluoropropene, 3-chloro-1,2,3-trifluoropropene (E and Z isomers), 3-chloro-1,1,2-trifluoro Propen, 3,3-dichloro-3-fluoropropene, 1,2-dichloro-3,3,3-trifluoropropene (E and Z isomers), 2-chloro-1,1,1,4,4 Group consisting of 4-hexafluoro-2-butene (E and Z isomers) and 2-chloro-1,1,1,3,4,5,4-heptafluoro-2-butene (E and Z isomers) The phenolic resin foam according to claim 1, which is at least one selected from. The phenolic resin foam according to claim 1 or 2, wherein the surfactant is at least one surfactant selected from the group consisting of a castor oil alkylene oxide adduct and a silicone-based surfactant.