JP7071821B2 - Phenol resin foam - Google Patents

Description

The present invention relates to a phenolic resin foam.

Phenol 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, a phenol resin foam wall board is used as a synthetic resin building material, particularly a wall board 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) and the like. The phenolic resin foam thus produced has closed cells, and the closed cells contain gas generated from the foaming agent.
It has been proposed to use a mixture of 2-chloropropane, which is a chlorinated aliphatic hydrocarbon, and isopentane, which is an aliphatic hydrocarbon, as a foaming agent for the phenolic resin foam. A phenolic resin foam using such a mixture as a foaming agent is said to have essentially no bubble defects and exhibit stable and low thermal conductivity (see Patent Document 1).
It has also been proposed to use a halogenated unsaturated hydrocarbon having a zero ozone depletion potential, a small warming coefficient, and a low thermal conductivity as a foaming agent for a phenolic resin foam (see Patent Document 2). ..

Japanese Patent No. 4939784 Japanese Patent No. 5688487

The heat insulating material made of phenolic resin foam may be installed in an environment that tends to be humid, such as the foundation of a building, and even if the atmospheric humidity rises, the amount of water absorbed by the heat insulating material does not increase and the performance is stable. It is required to do.
An object of the present invention is to provide a phenolic resin foam having less water absorption when the atmospheric humidity rises.

The present inventors have increased the water absorption of the phenolic resin foam when a saturated hydrocarbon having a halogen atom or an unsaturated hydrocarbon is used as compared with the case where an aliphatic hydrocarbon (alkane) is used as a foaming agent. I found it easy.
Then, paying attention to the equilibrium water content of the phenolic resin foam at room temperature, it was found that when the equilibrium water content is low, the inflow and outflow (moisture absorption and desorption) of water in the phenolic resin foam is small, and the present invention has been made.

The present invention has the following aspects.
<1> Containing a phenol resin and a halogenated hydrocarbon, the density is 15 to 50 kg / m ³ , the average cell diameter is 50 to 200 μm, the closed cell ratio is 85% or more, the temperature is 23 ° C, and the relative humidity is 50%. A phenolic resin foam having an equilibrium water content of 6% by mass or less.
<2> The phenolic resin foam of <1>, wherein the difference between the wet water content at a temperature of 23 ° C. and a relative humidity of 90% and the equilibrium water content at a temperature of 23 ° C. and a relative humidity of 50% is 2% by mass or less.
<3> The phenolic resin foam of <1> or <2> containing isopropyl chloride as the halogenated saturated hydrocarbon.
<4> The halogenated unsaturated hydrocarbon contains one or both of 1,1,1,4,4,4-hexafluoro-2-butene and 1-chloro-3,3,3-trifluoropropene. The phenolic resin foam according to any one of <1> to <3>.

According to the present invention, a phenol resin foam having less water absorption when the atmospheric humidity rises can be obtained.

The phenolic resin foam of the present invention contains a cured phenolic resin and a foaming agent. The foaming agent contains a halogenated hydrocarbon.
The phenolic resin foam of the present invention can be obtained by a method including foaming and curing a foamable phenolic resin composition containing a phenolic resin, a foaming agent, and an acid catalyst.
In the case of so-called in-foundation heat insulation in which a heat insulating material is installed inside the foundation of a building, since there is no ventilation hole for discharging moisture, the humidity generated from the foundation becomes a problem of deterioration of heat insulating performance. Since the phenolic resin foam of the present invention has a low equilibrium water content and low moisture absorption and desorption, the thermal conductivity is unlikely to decrease even in a humid environment such as the foundation of a building.
When the phenolic resin foam of the present invention is installed on the foundation of a building, it can be provided on both the vertical and horizontal portions of the indoor side of the foundation having a substantially L-shaped cross section, and the inner surface of the foundation and the phenolic resin foam can be provided. It is installed so that it comes into contact with the face material.

<Phenol resin>
As the phenol resin, a resol type is preferable.
The resole-type phenol resin is a phenol resin obtained by reacting a phenol 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 alkaline catalyst are not limited to the above.
The ratio of the phenol compound and 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.

The weight average molecular weight Mw determined by gel permeation chromatography of a phenol resin is usually 400 to 3000, preferably 700 to 2000. When the weight average molecular weight Mw is smaller than 400, the closed cell ratio tends to decrease, which tends to lead to a decrease in compressive strength and a decrease in long-term performance of thermal conductivity. In addition, a foam having many voids and a large average bubble diameter is likely to be formed. When the weight average molecular weight Mw is larger than 3000, the viscosity of the phenol resin raw material and the phenol resin composition becomes too high, so that a large amount of foaming agent is required to obtain the required foaming ratio. If there is a lot of foaming agent, it is not economical.

<Effervescent agent>
The foaming agent contains halogenated hydrocarbons. Further, saturated hydrocarbons may be contained. Halogenated hydrocarbons can be roughly classified into halogenated saturated hydrocarbons and halogenated unsaturated hydrocarbons.
[Halogenated unsaturated hydrocarbon]
Examples of halogenated unsaturated hydrocarbons include fluorinated unsaturated hydrocarbons, chlorinated unsaturated hydrocarbons, chlorinated fluorinated unsaturated hydrocarbons, brominated fluorinated unsaturated hydrocarbons, and iodide fluorinated unsaturated hydrocarbons. Can be mentioned. The halogenated unsaturated hydrocarbon may be one in which all hydrogen atoms are substituted with halogen atoms, or a part of hydrogen atoms may be substituted with halogen atoms.
As the halogenated unsaturated hydrocarbon, those having a fluorine atom such as a fluorinated unsaturated hydrocarbon and a chlorinated unsaturated hydrocarbon are preferable.
These halogenated unsaturated hydrocarbons may be used alone or in combination of two or more.

Examples of the chlorinated fluorinated unsaturated hydrocarbon include those containing a chlorine atom, a fluorine atom and a carbon-carbon double bond in the molecule, and examples thereof include 1,2-dichloro-1,2-difluoroethene (E and). Z isomer), 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) (E and Z isomer) (eg, 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 isomers), 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) (eg, SynQuest Laboratories, product number: 1300-7-09), 3-chloro-1,2,3-trifluoropropene (HCFO-1233ye) (E and Z isomers). Body), 3-chloro-1,1,2-trifluoropropene (HCFO-1233yc), 3,3-dichloro-3-fluoropropene, 1,2-dichloro-3,3,3-trifluoropropene (HFO) -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 1,3,4,4,4-heptafluoro-2-butene (E and Z isomers) and the like can be mentioned.
Those containing a hydrogen atom, a chlorine atom, a fluorine atom and a carbon-carbon double bond (HCFO) in the molecule are more preferable.

Examples of the fluorinated unsaturated hydrocarbon include hydrofluoroolefins (hereinafter, also referred to as “HFO”) containing a hydrogen atom, a fluorine atom, and a carbon-carbon double bond in the molecule, and examples thereof include 2, 3, and 3. , 3-Tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO-1234ze) (E and Z isomers), 1,1,1,4,4,4-Hexafluoro Examples thereof are those disclosed in Japanese Patent Publication No. 2009-513812 such as -2-butene (HFO1336mzz) (E and Z isomers) (for example, manufactured by SynQuest Laboratories, product number: 1300-3-Z6).

The halogenated unsaturated hydrocarbon contained in the foaming agent is advantageous in that it has a small ozone depletion potential (ODP) and a global warming potential (GWP) and has a small impact on the environment. As the halogenated unsaturated hydrocarbon, a chlorinated fluorinated unsaturated hydrocarbon or a fluorinated unsaturated hydrocarbon is preferable.

[Halogenated saturated hydrocarbon]
As the halogenated saturated hydrocarbon, a known foaming agent can be used, and examples thereof include fluorinated saturated hydrocarbons and chlorinated saturated hydrocarbons. The halogenated saturated hydrocarbon may be one in which all the hydrogen atoms are substituted with halogen atoms, or the hydrogen atoms may be partially substituted with halogen atoms.
The halogenated saturated hydrocarbon may be used alone or in combination of two or more.

The chlorinated saturated hydrocarbon preferably has 2 to 5 carbon atoms. Chlorinated aliphatic hydrocarbons are more preferred. Examples thereof include dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, isopentyl chloride and the like.
Among the above, isopropyl chloride (also known as 2-chloropropane) is preferable because it has a low ozone depletion potential and is excellent in environmental compatibility.

The fluorinated saturated hydrocarbon preferably has 1 to 5 carbon atoms. For example, difluoromethane (HFC32), 1,1,1,2,2-pentafluoroethane (HFC125), 1,1,1-trifluoroethane (HFC143a), 1,1,2,2-tetrafluoroethane ( HFC134), 1,1,1,2-tetrafluoroethane (HFC134a), 1,1-difluoroethane (HFC152a), 1,1,1,2,3,3,3-heptafluoropropane (HFC227ea), 1, 1,1,3,3-pentafluopropane (HFC245fa), 1,1,1,3,3-pentafluobtan (HFC365mfc) and 1,1,1,2,2,3,4,5,5 , 5-Decafluoropentane (HFC4310mee) and other hydrofluorocarbons.

[Saturated hydrocarbons]
The saturated hydrocarbon preferably has 3 to 7 carbon atoms. Examples thereof include butane, isobutane, pentane, isopentane, cyclopentane, hexane, heptane and the like.

The foaming agent may further contain other foaming agents other than the above-mentioned halogenated unsaturated hydrocarbons, halogenated saturated hydrocarbons, and saturated hydrocarbons, if necessary. Other effervescent agents include low boiling point gases such as nitrogen, argon, carbon dioxide, air; sodium hydrogencarbonate, sodium carbonate, calcium carbonate, magnesium carbonate, azodicarboxylic acid amide, azobisisobutyronitrile, azodicarboxylic acid barium. , N, N'-dinitrosopentamethylenetetramine, p, p'-oxybisbenzenesulfonylhydrazide, trihydrazinotriazine and other chemical foaming agents; porous solid materials and the like.

The content of the foaming agent in the phenol resin foam (or foamable phenol resin composition) is preferably 1 to 25 parts by mass, more preferably 3 to 15 parts by mass, and 5 to 11 parts by mass per 100 parts by mass of the phenol resin. Phenol is more preferred.
The proportion of the halogenated hydrocarbon in 100 parts by mass of the foaming agent is preferably, for example, 20 parts by mass or more, and more preferably 30 parts by mass or more. It may be 100 parts by mass.

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. It is almost the same. The composition of two or more kinds of foaming agents 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 unsaturated hydrocarbon, halogenated saturated hydrocarbon, or saturated hydrocarbon in advance, the holding time under the following measurement conditions on a gas chromatograph-mass spectrometer (GC / MS) is determined. Next, 1.6 g of a sample of the 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 hydrocarbon is identified from the retention time and mass spectrum obtained in advance. The detection sensitivity of the foaming agent component 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
Measurement method: Scanning method m / Z = 11 to 550

<Additives>
(Acid catalyst)
The acid catalyst is included in the effervescent phenolic resin composition to cure 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 phenol resin composition is preferably 5 to 30 parts by mass, more preferably 8 to 25 parts by mass, still more preferably 10 to 20 parts by mass, per 100 parts by mass of the phenol resin.

(Surfactant)
It is preferable to include a surfactant in the effervescent phenol resin composition. Surfactants contribute to the miniaturization of bubble diameter (cell diameter).
The surfactant is not particularly limited, and known defoaming agents and the like can be used. For example, castor oil alkylene oxide adduct, silicone-based surfactant, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl ether and the like can be mentioned. These surfactants may be used alone or in combination of two or more.
It is preferable to use a surfactant having an HLB of 8 to 18. When the HLB of the surfactant is within the above range, it is easy to obtain a phenol resin foam having less water absorption when the atmospheric humidity rises. The HLB of the surfactant is more preferably 10 to 14. When a plurality of types of surfactants are mixed and used, the HLB is a weighted average of the HLBs of each component.
When the phenol resin foam contains a surfactant, the content of the surfactant in the foamable phenol resin composition is preferably 1 to 8 parts by mass per 100 parts by mass of the phenol resin, more preferably 3 to 5 parts by mass. preferable. When the content of the surfactant is not less than the lower limit of the above range, the bubble diameter tends to be uniformly reduced, and when it is not more than the upper limit, a phenol resin foam having less water absorption when the atmospheric humidity rises can be obtained. Cheap.

The surfactant used in the present invention can detect and quantify the content in the phenolic resin foam from a relatively low concentration to a high concentration by analysis by the following measuring devices.

The first measuring device is a matrix-assisted laser desorption / ionization-time-of-flight mass spectrometer (MALDI-TOF / MS). In the analysis by this device, the mixture of the matrix and the measurement sample is irradiated with laser light, and the sample molecules are ionized through the matrix. Because of the soft ionization, it is possible to ionize the sample molecules without decomposing them. The feature is that even tall molecules can be measured.

The next measuring device is NMR. This device is a measuring device using nuclear magnetic resonance, and the position of the peak (chemical shift) measured by the chemical environment of the nuclear species is different, so that the structure of the substance to be measured can be specified. Further, since the molar ratio can be quantified from the integral value of the peak, the surfactant used in the present invention can be quantified by using the internal standard method.

In order to analyze the surfactant in the phenol resin foam, it is first necessary to extract the surfactant from the phenol resin foam. For example, a phenolic resin foam is cut to a certain size, mashed with a pestle or mortar, and used as a fine powder using a Soxley extractor. About 1 gram of fine powder is used for about 8 hours, and the solvent is chloroform. Extract. The amount of the extract can be determined by drying the extracted material and measuring the weight. The dried product is measured by MALDI-TOF / MS. At this time, a sodium iodide / acetone solution can be used as the ionization aid, and a disanol / chloroform solution can be used as the matrix.
For example, when measuring a polyoxyethylene stearyl ether having an alkyl group C18 with HLB = 17.6, the most frequent peak appears near 2010 and the peak interval is detected at about 44. From this detection state, the presence of polyoxyethylene alkyl ether and the abundance can be estimated from the height (strength) of the peak.

Further, using the same dried sample as above, dissolve in a deuterated chloroform solvent, and use dimethyl sulfoxide as an internal standard substance by NMR, for example, from the peak intensities appearing at 2.6 PPM and 3.6 PPM at 400 MHz. Identify the amount of polyoxyethylene alkyl ether in the dry sample. When the above-mentioned polyoxyethylene stearyl ether having an alkyl group C18 having HLB = 17.6 is measured from the phenol resin foam, components other than the surfactant are also extracted in the soxley extraction, so that a known sample is used. , The amount of the surfactant added and the amount of the surfactant in the Soxley extract are determined in the foam using a calibration curve. By measuring in this way, it is possible to measure the amount of the surfactant present in the phenol resin foam with high accuracy even if the content in the sample is extremely small.

(Other ingredients)
As other components, those known as additives for the phenolic resin foam can be added to the effervescent phenolic resin composition, for example, urea, a plasticizer, a filler, a flame retardant (for example, a phosphorus-based flame retardant), and the like. Examples thereof include a cross-linking agent, an organic solvent, an amino group-containing organic compound, and a colorant.

<Manufacturing method>
The effervescent phenol resin composition can be prepared by mixing each of the above components.
The mixing order of each component is not particularly limited, but for example, a surfactant or other components are added to a phenol resin as necessary to mix the whole, and a foaming agent and an acid catalyst are added to this mixture to form this composition. The effervescent phenol resin composition can be prepared by supplying the above to a mixer and stirring the mixture.

The phenolic resin foam of the present invention can be produced by foaming and curing the foamable phenolic resin composition.
The phenol resin foam can be produced by a known method. For example, a phenolic resin foam is produced by heating a foaming phenol resin composition in a heating furnace to foam and cure it (foaming / curing step), and then curing and drying it in a dryer (curing / drying step). A method of performing a curing / drying step is performed with a discharge device, a foam molding device arranged on the downstream side of the discharge device to perform a foaming / curing step, and a cutting device arranged on the downstream side of the foam molding device. A manufacturing system equipped with a curing cabinet is used.
The discharge device includes a mixing unit for mixing raw materials such as phenol resin, and a plurality of nozzles arranged along a direction orthogonal to the flow direction for discharging the mixed raw materials (foamable phenol resin composition). To prepare for.
The foam molding apparatus includes a frame portion and heating means. The frame portion includes conveyors (lower conveyor, upper conveyor, left side conveyor, right side conveyor) arranged vertically and horizontally so as to form a space corresponding to the cross-sectional shape of the phenol resin foam. The lower and upper conveyors regulate vertical foaming, and the left and right conveyors regulate left and right foaming. The effervescent phenolic resin composition that passes through the frame portion is heated, foamed, and cured by the heating means. Examples of such a foam molding apparatus include those described in JP-A-2000-218635.
It should be noted that a through hole may be formed in each conveyor to serve as a moisture escape route capable of releasing the moisture generated during curing to the outside.

In this manufacturing system, first, the first face material is continuously supplied between the discharge device and the foam molding device. The effervescent phenolic resin composition is ejected from a plurality of nozzles onto the first face material by the ejection device. A second face material is placed on it, introduced into the frame portion of the foam molding apparatus, and heated at 30 to 95 ° C. As a result, the effervescent phenol resin composition is foamed and cured between the first face material and the second face material, and a phenol resin foam is formed. This phenol resin foam is derived from a foam molding device and cut to an arbitrary length by a cutting device. As a result, a phenol resin foam having a first face material provided on one surface and a second face material provided on the other surface can be obtained.

Subsequently, the cut phenol resin foam is stored in a curing chamber, and a curing / drying step is performed.
The curing / drying process is performed by adjusting the temperature and time in the curing chamber. In the range of heating temperature of 80 ° C. or higher and 90 ° C. or lower, it is preferable to carry out for 4.5 hours or more and 12 hours or less. Further, in the range where the heating temperature is 91 ° C. or higher and 120 ° C. or lower, it is preferable to carry out the heating for 1 hour or more and less than 4.5 hours.
By curing and drying within the above temperature and time range, it is possible to prevent the bubble diameter from becoming coarse and the closed cell ratio from decreasing, and to reduce the equilibrium moisture content.

<Face material>
When the phenol resin foam is produced by foam molding, a face material may be provided. The face material and the foam layer are bonded to each other without passing through an adhesive layer, and are directly bonded to the face material by the bonding force of the phenol resin itself constituting the foam layer.
The face material is not particularly limited, and is not particularly limited. At least one selected from boards, metal foils, plywood, calcium silicate boards, gypsum boards and wood-based cement boards is suitable, and in particular, glass fiber mixed paper, glass fiber non-woven paper, and synthetic fiber non-woven paper are industrially distributed. It is easy to obtain and preferable because of the large amount. Among them, the synthetic fiber nonwoven fabric is preferable because it is possible to control the texture and fluffing of the surface layer of the nonwoven fabric by changing the heat fusion point pattern between the fibers by embossing heating rolls in manufacturing, and it is easy to handle. Further, when the face material is a synthetic fiber non-woven fabric, it is possible to suppress the shrinkage of the face material and the occurrence of wrinkles due to the water content in the foamable phenol resin composition and the water generated during the condensation of the phenol resin. Further, since the face material made of the synthetic fiber non-woven fabric itself has lower water absorption than the face material containing cellulose fibers and the like, the water absorption amount of the phenol resin foam can be further reduced.

The face material may be provided on one side of the phenolic 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 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 onto the face material. Examples thereof include a method of laminating other face materials and then passing them through a heating furnace for foam molding. As a result, a phenol 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 sticking it to a phenol resin foam using an adhesive after foam molding.

The texture of the face material is not particularly limited, but when a synthetic fiber non-woven fabric is used, the texture is preferably 15 g / m ² or more and 200 g / m ² or less, and 15 g / m ² or more and 150 g / m ² or less. More preferably, it is more preferably 15 g / m ² or more and 100 g / m ² or less, particularly preferably 20 g / m ² or more and 80 g / m ² or less, and 20 g / m ² or more and 60 g / m ² or less. Most preferably.
When glass fiber mixed paper is used, the grain size is preferably 30 g / m ² or more and 300 g / m ² or less, more preferably 50 g / m ² or more and 250 g / m ² or less, and 60 g / m ² or more. It is more preferably 200 g / m ² or less, and particularly preferably 70 g / m ² or more and 150 g / m ² or less.
When a glass fiber non-woven fabric is used, the texture is preferably 15 g / m ² or more and 300 g / m ² or less, more preferably 20 g / m ² or more and 200 g / m ² or less, and 30 g / m ² or more and 150 g. It is more preferably / m ² or less.
When the basis weight is at least the above lower limit value, the effervescent phenol resin composition does not easily seep out to the surface of the face material. When the basis weight is not more than the above upper limit value, the adhesiveness between the foam and the face material can be enhanced. As a result, the face material is less likely to peel off from the foam, and the surface can be made more beautiful. In addition, it becomes easy to follow the transport equipment such as a conveyor, and it becomes easy to increase the productivity of the phenol resin foam. In particular, when the foaming agent contains a halogenated hydrocarbon, the viscosity of the foamable phenol resin composition is lowered by containing the foaming agent. When the viscosity of the composition is low, the composition is likely to seep into the face material, and the composition is likely to seep out onto the surface of the face material. Therefore, the basis weight of the face material should be at least the above lower limit. It is possible to prevent the composition from exuding.

The thickness of the face material is not particularly limited, but is preferably 0.06 to 1.00 mm, more preferably 0.10 to 0.50 mm. When the thickness of the face material is at least the above lower limit value, the exudation of the face material to the surface is likely to be suppressed. When the thickness of the face material is not more than the upper limit value, the handleability of the face material is improved.

When the face material is a synthetic fiber non-woven fabric, examples of the material of the synthetic fiber non-woven fabric include synthetic resins such as polyester, polypropylene, nylon, and polyethylene. Polyester, polypropylene and nylon are preferred. One of these synthetic resins may be used alone, or two or more thereof may be used in combination.
The fiber diameter of the synthetic fiber of the synthetic fiber nonwoven fabric is preferably 0.5 to 4.0 denier, more preferably 1.5 to 3.0 denier.
When the fiber diameter of the synthetic fiber is not more than the upper limit value, it is easy to suppress the exudation of the face material to the surface.
When the fiber diameter of the synthetic fiber is at least the above lower limit value, the handleability of the synthetic fiber is improved and the non-woven fabric is easily manufactured.

When the face material is a synthetic fiber non-woven fabric, it is preferable that a so-called emboss (thermocompression bonding fixing portion) having an uneven shape is formed. By using the embossed face material, the adhesiveness between the face material and the foamable resin composition is further enhanced.
The embossing pattern (pattern) is not particularly limited, and examples thereof include a minus pattern, a point pattern, and a texture pattern. A textured pattern or a minus pattern is preferable because the uneven shape due to embossing is large and the adhesiveness to the foam layer can be further enhanced.
To emboss the synthetic fiber non-woven fabric, for example, by using a known spunbond method, the crimped fiber web developed under the cooling conditions directly under the spun is partially thermocompression bonded with a thermal embossing roll, or latent winding. It is manufactured by crimping a crimped fiber web by heat treatment and partially thermocompression bonding with a thermal embossing roll.

In the thermocompression bonding fixing portion formed during embossing, the area per thermocompression bonding fixing portion is preferably 0.05 mm ² or more and 5.0 mm ² or less, and more preferably 0.07 mm ² or more and 3.0 mm ² or less. .. By using the face material within this range, the adhesiveness between the foamable resin composition and the face material can be improved while suppressing the exudation of the foamable resin composition by the thermocompression bonding fixing portion. When the area is less than 0.05 mm ² , the fibers are less bonded to each other, the physical strength such as frictional strength is low, and the foamable resin composition tends to exude. When the area exceeds 5.0 mm ² , thermocompression bonding is performed. The area of the fixed portion is large, the texture is hard, and the adhesiveness between the foamed resin layer and the fibers of the face material is poor. Further, the air permeability may be low, the curing time may be long, and the closed cell ratio may be lowered.

The minimum distance between the thermocompression bonding fixing portions is preferably 0.05 mm or more and 5 mm or less, and more preferably 0.08 mm or more and 2 mm or less. By using the face material within this range, it is possible to improve the adhesiveness between the foamed resin layer and the face material while suppressing the exudation of the phenol resin. When the minimum spacing is less than 0.05 mm, there are many thermocompression-bonded fixing portions, the texture is hard, and the adhesiveness between the foam layer and the fibers of the face material tends to be poor. When it exceeds 5 mm, the bonds between the fibers are small, the physical strength such as frictional strength is low, and the foamable resin composition easily exudes. Further, it is preferable that the thermocompression bonding fixing portions are evenly distributed on the entire surface of the non-woven fabric surface.

The thermocompression bonding fixed part density is 5 pieces / cm ² or more and 150 pieces / cm ² or less, more preferably 5 pieces / cm ² or more and 50 pieces / cm ² or less, and 5 pieces / cm ² or more and 30 pieces / cm ² or less. More preferred. The thermocompression bonding fixed portion density means the number of thermocompression bonding fixing portions per unit area, and is expressed by the following equation (s).
Thermocompression bonding fixed part density (pieces / cm ² ) = [Number of thermocompression bonding fixing parts (pieces)] / "[Surface area of face material (cm ² )] ... (s)
When the thermocompression bonding fixed partial density is at least the above lower limit value, the exudation of the foamable resin composition can be satisfactorily suppressed. When the thermocompression bonding fixed partial density is not more than the above upper limit value, the adhesiveness between the foamed resin layer and the face material can be further improved, and the water absorption amount can be lowered. Further, when the thermocompression bonding fixed partial density is not more than the above upper limit value, the air permeability can be increased and the curing time can be shortened. In addition, low thermal conductivity can be maintained for a longer period of time.

<Physical characteristics>
[density]
The density of the phenolic resin foam of the present invention is 15 to 50 kg / m ³ , preferably 20 to 40 kg / m ³ , and more preferably 25 to 35 kg / m ³ . When it is at least the above lower limit value, it is easy to further improve the compressive 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 density is adjusted by the type and composition of the foaming agent, the type of the surfactant, the foaming conditions (heating temperature, heating time, etc.) and the like.
The method for measuring the density will be described later.

[Average bubble diameter (cell diameter)]
The average cell diameter of the phenolic resin foam of the present invention is 50 to 200 μm, preferably 50 to 150 μm, and more preferably 50 μm to 100 μm. When the average cell diameter is within the above range, the heat insulating property of the phenol resin foam can be further enhanced.
The average cell diameter is adjusted by a combination of the type or composition of the foaming agent, the type of the surfactant, the foaming conditions (heating temperature, heating time, etc.) and the like.
The method for measuring the average bubble diameter will be described later.

[Closed cell ratio]
The closed cell ratio of the phenolic resin foam of the present invention is, for example, 85% or more, preferably 90% or more, more preferably 95% or more, and may be 100%. When the closed cell ratio is at least the above lower limit value, the heat insulating property of the phenol resin foam can be further enhanced.
The closed cell ratio is adjusted by a combination of the type or composition of the foaming agent, the type of the surfactant, the foaming conditions (heating temperature, heating time, etc.) and the like.
The method for measuring the closed cell ratio will be described later.

[Equilibrium moisture content]
The phenolic resin foam of the present invention has an equilibrium water content of 6% by mass or less at a temperature of 23 ° C. and a relative humidity of 50%, preferably 5.5% by mass or less, and more preferably 5% by mass or less. The lower the equilibrium water content, the less the moisture absorption and desorption in the phenol resin foam, and the less water absorption when the atmospheric humidity rises, the less the phenol resin foam can be obtained.
When the conditions of the curing / drying step are constant, the equilibrium water content can be adjusted by the type and amount of the surfactant added.
The method for measuring the equilibrium water content will be described later.

[Wet water content / water content difference]
As an index of the water absorption of the phenolic resin foam when the atmospheric humidity rises, the difference between the wet moisture content at a temperature of 23 ° C and a relative humidity of 90% and the equilibrium moisture content at a temperature of 23 ° C and a relative humidity of 50% (book). In the specification, simply "water content difference") can be used. The smaller the difference in water content, the smaller the amount of water absorbed due to the increase in atmospheric humidity.
The method for measuring the wet water content will be described later.
The wet water content of the phenolic resin foam of the present invention is preferably 8% by mass or less, more preferably 7.5% by mass or less, still more preferably 7% by mass or less. The lower the wet moisture content, the less water is absorbed when the humidity rises, and the more stable the performance is.
The difference in water content of the phenolic resin foam of the present invention is a value obtained by subtracting the equilibrium water content from the wet water content. The difference in water content is preferably 2% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1% by mass or less. The lower the wet moisture content, the less water is absorbed when the humidity rises, and the more stable the performance is.

<Mechanism of action>
According to the present invention, even if the foaming agent contains a halogenated hydrocarbon, a phenol resin foam having less water absorption when the atmospheric humidity rises can be obtained. The reason why the water absorption of the phenolic resin foam is more likely to increase when a halogenated hydrocarbon is used than when an aliphatic hydrocarbon (alkane) is used as a foaming agent is considered as follows.
Since the halogenated hydrocarbon has a high polarity and is highly compatible with the phenol resin, the phenol resin is likely to be plasticized if the foaming agent contains the halogenated hydrocarbon. When the phenol resin is plasticized, it is difficult to form a strong bubble wall in the phenol resin foam, so that the foaming agent in the bubbles tends to easily replace the air. Such a phenol resin foam tends to contain water under wet conditions, and the amount of water absorption of the foam increases, which causes a decrease in performance.
Further, as shown in Examples described later, by changing the type of the surfactant, the equilibrium water content at room temperature can be lowered, and the water absorption amount (water content difference) when the atmospheric humidity rises can be obtained. It can be made smaller. It is considered that the reason is that the action of the surfactant in the effervescent phenol resin composition changes the solubility of the halogenated hydrocarbon in the phenol resin, and the plasticization of the phenol resin can be suppressed.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
<Measurement method>
The method for measuring the physical properties of the phenolic resin foam is as follows.
[density]
The density is measured according to JIS A 9511: 2009, and the density of the phenolic resin foam is measured.

[Average bubble diameter (cell diameter)]
A test piece is 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 is photographed at a magnification of 50 times. Draw four straight lines with a length of 9 cm on the captured image. At this time, draw a straight line 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 K640-1: 2004) is counted for each straight line, and the average value per straight line is obtained. Divide 1800 μm by the average value of the number of bubbles, and use the obtained value as the average bubble diameter.
[Closed cell ratio]
The closed cell ratio of the phenolic resin foam is measured according to JIS K7138-2006.

[Equilibrium moisture content]
The obtained phenol resin foam with face material was cut into 200 mm in the width direction and 200 mm in the length direction, and then left for 7 days in an atmosphere having a temperature of 23 ° C. and a relative humidity of 50%. Let it be m ₀ . The phenol resin foam is placed in an oven at 104 ° C. and the mass 48 hours later is set to m ₁ , and the equilibrium water content (unit: mass%) is determined by the following formula (1).
Equilibrium water content = (m ₀ − m ₁ ) / m ₀ × 100… (1)

[Wet moisture content]
The obtained phenolic resin foam with a face material was cut into a width direction of 200 mm and a length direction of 200 mm, and then left in an atmosphere having a temperature of 23 ° C. and a relative humidity of 50% for 7 days, and then having a temperature of 23 ° C. and a relative humidity of 90. The mass of the phenol formaldehyde foam left in the atmosphere of% for 7 days is defined as the initial mass _k0 . The phenol resin foam is put into an oven at 104 ° C., the mass after 48 hours is k ₁ , and the wet water content (unit: mass%) is determined by the following formula (2).
Wet moisture content = (k ₀ -k ₁ ) / k ₀ x 100 ... (2)

Table 1 shows the foaming agents used in the following Examples and Comparative Examples. The following surfactants were used.
Surfactant (1): Castor oil fatty acid PEG ester (Ito Oil Chemicals, Inc. "SURFRIC AQ-250"), HLB = 11.
Surfactant (2): Silicone-based surfactant (Shinetsu Silicone Co., Ltd. "KF-615A"), HLB = 10.
Surfactant (3): Silicone-based surfactant (Toray Dow Corning "SF-2945F"), HLB = 13.
Surfactant (4): Fluorine-based surfactant (AGC Seimi Chemical Co., Ltd. "Surflon s-243"), HLB = 15.
Surfactant (5): Alkyl ether-based surfactant (Nikko Chemicals, Inc. "NIKKOL BB-20"), HLB = 16.5
Surfactant (6): Fatty acid ester-based surfactant (Nikko Chemicals, Inc. "NIKKOL MYS-40MV"), HLB = 17.5
Surfactant (7): Silicone-based surfactant (Toray Dow Corning "SH-193"), HLB = 19.
<Examples 1-8, 11, 12>
Examples 1, 3 to 5 are Examples, Examples 2, 6 to 8 are Reference Examples, and Examples 11 and 12 are Comparative Examples. Table 2 shows the types of foaming agents (A to H in Table 1), the types of surfactants ((1) to (7) above), and the amount added in each example (the same applies hereinafter).

A phenolic resin foam was produced by the following method.
A surfactant is added to 100 parts by mass of a liquid resol type phenol resin (manufactured by Asahi Organic Materials Industry Co., Ltd., trade name: PF-339), and 4 parts by mass of urea is added as a formaldehyde catcher and mixed, and the mixture is mixed at 20 ° C. It was left for 8 hours.
A foaming agent was added to the mixture thus obtained, 16 parts by mass of a mixture of paratoluene sulfonic acid and xylene sulfonic acid was added as an acid catalyst, and the mixture was stirred and mixed to prepare an effervescent phenolic resin composition. ..
This effervescent phenolic resin composition is continuously run on a first face material (material: glass fiber mixed papermaking, grain: 80 g / m ² ), and the running direction of the first face material (hereinafter, length). It was ejected from 18 nozzles arranged at equal intervals in the direction perpendicular to the vertical direction (also referred to as the width direction) (hereinafter, also referred to as the width direction). A second face material of the same material as the first face material was layered on top of it. The uncured material in which the foamable phenol resin composition layer is sandwiched between the upper surface of the first face material and the lower surface of the second face material is introduced into a slat type double conveyor and heated at 70 ° C. for 300 seconds. After foam molding (foaming / curing step) and drying in a curing chamber at 80 ° C. for 5 hours (curing / drying step), the phenol resin is cut into 1820 mm in the width direction and 910 mm in the length direction, and has a thickness of 45 mm. A foam was produced.
By the above method, the density, the average bubble diameter, the closed cell ratio, the equilibrium moisture content, and the wet moisture content were measured, respectively, and the difference in moisture content was determined. The results are shown in Table 2 (the same applies hereinafter).

<Example 9>
Example 9 is a reference example . A phenolic resin foam was produced by the following method.
An effervescent phenolic resin composition was prepared in the same manner as in Example 1.
This effervescent phenolic resin composition is placed on a first face material (material: polyester non-woven fabric, texture: 20 g / m ² , thermocompression bonding fixed partial density: 8 pieces / cm ² ) that runs continuously. It was ejected from 18 nozzles arranged at equal intervals in the width direction of the face material. A second face material of the same material as the first face material was layered on top of it. The uncured material in which the foamable phenol resin composition layer is sandwiched between the upper surface of the first face material and the lower surface of the second face material is introduced into a slat type double conveyor and heated at 70 ° C. for 300 seconds. After foam molding (foaming / curing step) and drying in a curing chamber at 95 ° C. for 2 hours (curing / drying step), the phenol resin is cut into 1820 mm in the width direction and 910 mm in the length direction, and has a thickness of 45 mm. A foam was produced.

<Example 10>
Example 10 is a reference example . A phenolic resin foam was produced by the following method.
In Example 10, a phenolic resin foam with a face material was produced by the same method as in Example 9 except that the curing and drying steps were dried at 110 ° C. for 3 hours.

As shown in the results of Table 2, in Examples 1 to 10 in which the equilibrium water content was 6% by mass or less, a phenol resin foam having a small difference in water content and less water absorption due to an increase in atmospheric humidity was obtained. The physical characteristics of the phenolic resin foam were also good.
On the other hand, the phenolic resin foams obtained in Examples 11 and 12 having an equilibrium water content of more than 6% by mass had a large difference in water content and absorbed a large amount of water due to an increase in the humidity of the atmosphere.

Claims (4)

It contains a phenolic resin, a surfactant, and a foaming agent containing halogenated hydrocarbons and saturated hydrocarbons .
The content of the halogenated hydrocarbon is 30 parts by mass or more with respect to 100 parts by mass of the foaming agent.
The HLB of the surfactant is 10 to 14,
The density is 15 to 50 kg / m ³ , the average bubble diameter is 50 to 150 μm, the closed cell ratio is 90 % or more, the equilibrium water content at a temperature of 23 ° C. and a relative humidity of 50% is 6% by mass or less, and the temperature. A phenolic resin foam having a difference of 2% by mass or less between a wet moisture content at a temperature of 23 ° C. and a relative humidity of 90% and an equilibrium moisture content at a temperature of 23 ° C. and a relative humidity of 50% . The phenolic resin foam according to claim 1 , wherein the halogenated hydrocarbon contains isopropyl chloride as a halogenated saturated hydrocarbon. The halogenated hydrocarbon is one or both of 1,1,1,4,4,4-hexafluoro-2-butene and 1-chloro-3,3,3-trifluoropropene as halogenated unsaturated hydrocarbons. The phenolic resin foam according to claim 1 or 2 , which comprises. The phenolic resin foam according to any one of claims 1 to 3, wherein the saturated hydrocarbon has 3 to 7 carbon atoms .