JP2018095872A - Phenol resin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phenol resin foam which prevents adhesion of chips.SOLUTION: A phenol resin foam contains a phenol resin and halogenated unsaturated hydrocarbon, and has a density of 15-50 kg/m, an average cell diameter of 200 μm or less, a closed cell ratio of 80% or more and surface resistivity of 1×10Ω/sq. or less.SELECTED DRAWING: None

Description

  The present invention relates to a phenolic 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 construction field, a phenol resin foam is employed as a heat insulating material for synthetic resin building materials, particularly wallboards.
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 phenol resin foam thus produced has closed cells, and the closed cells contain a gas generated from the blowing 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 blowing agent for the phenol resin foam. A phenol resin foam using such a mixture as a foaming agent is essentially free from bubble defects and is said to exhibit stable and low thermal conductivity (see Patent Document 1).

Japanese Patent No. 4939784

According to the knowledge of the present inventors, when constructing a phenol resin foam, fine chips generated when cut are likely to adhere to the phenol resin foam and are difficult to clean.
An object of this invention is to provide the phenol resin foam which a chip does not adhere easily.

  The inventors focused on the surface resistivity of the phenol resin foam. If the surface resistivity is reduced, it becomes difficult to be charged with static electricity, and chip adhesion can be suppressed.

The present invention has the following aspects.
<1> A phenol resin and a halogenated unsaturated hydrocarbon are contained, the density is 15 to 50 kg / m ³ , the average cell diameter is 200 μm or less, the closed cell rate is 80% or more, and the surface resistivity is 1 × 10 ^12. A phenolic resin foam that is Ω / □ or less.
<2> The phenol resin foam according to <1>, wherein the equilibrium water content is 3 to 10% by mass.

  According to the present invention, it is possible to obtain a phenol resin foam to which chips do not easily adhere.

The phenol resin foam of the present invention contains a cured phenol resin and a foaming agent containing a halogenated unsaturated hydrocarbon.
The phenol resin foam of the present invention can be obtained by a method including foaming and curing a foamable phenol resin composition containing a phenol resin, a foaming agent containing a halogenated unsaturated hydrocarbon, and an acid catalyst. .

<Phenolic resin>
As the phenol resin, a resol type resin is preferable.
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 use ratio of the phenol compound and the aldehyde is not particularly limited. Preferably, the molar ratio of phenol compound: aldehyde is 1: 1 to 1: 3, more preferably 1: 1.3 to 1: 2.5.

  The weight average molecular weight Mw calculated | required by the gel permeation chromatography of a phenol resin is 400-3000 normally, Preferably it is 700-2000. If the weight average molecular weight Mw is less than 400, the closed cell ratio tends to decrease, which tends to cause a decrease in compressive strength and a decrease in long-term performance of thermal conductivity. In addition, a foam having a large number of voids and a large average cell diameter is easily 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 many foaming agents are required to obtain the necessary foaming ratio. When there are many foaming agents, it is not economical.

<Foaming agent>
The blowing agent includes a halogenated unsaturated hydrocarbon. Halogenated unsaturated hydrocarbons include fluorinated unsaturated hydrocarbons, chlorinated unsaturated hydrocarbons, chlorinated fluorinated unsaturated hydrocarbons, brominated fluorinated unsaturated hydrocarbons, iodinated fluorinated unsaturated hydrocarbons, etc. Is mentioned. The halogenated unsaturated hydrocarbon may be one in which all of the hydrogen atoms are substituted with halogen atoms, or one in which some of the hydrogen atoms are substituted with halogen atoms.
As a halogenated unsaturated hydrocarbon, what has a fluorine atom, such as a fluorinated unsaturated hydrocarbon and a chlorinated fluorinated unsaturated hydrocarbon, is preferable.
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 chlorinated fluorinated unsaturated hydrocarbon include those containing a chlorine atom, a fluorine atom and a carbon-carbon double bond in the molecule, such as 1,2-dichloro-1,2-difluoroethene (E and Z isomer), 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd) (E and Z isomers) (for example, 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-123) 3xc), 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) (eg, SynQuest Laboratories, product number: 1300-7-09), 3-chloro-1,2,3-tri Fluoropropene (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 (HFO-1223xd) (E and Z isomers), 2-chloro-1,1,1,4,4,4-hexafluoro-2-butene (E and Z isomers) And 2-chloro-1,1,1,3,4,4,4-heptafluoro-2-butene (E and Z variants) and the like.
More preferred are those containing a hydrogen atom, a chlorine atom, a fluorine atom and a carbon-carbon double bond (HCFO) in the molecule.

  Examples of the fluorinated unsaturated hydrocarbon include hydrofluoroolefin (hereinafter, also referred to as “HFO”) containing a hydrogen atom, a fluorine atom, and a carbon-carbon double bond in the molecule. , 3-tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO-1234ze) (E and Z isomers), 1,1,1,4,4,4-hexafluoro And 2-butene (HFO1336mzz) (E and Z isomers) (for example, SynQuest Laboratories, product number: 1300-3-Z6) and the like are disclosed in JP-T-2009-513812.

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

The blowing agent preferably further contains chlorinated saturated hydrocarbon or saturated hydrocarbon from the viewpoint of lowering the production cost.
As the chlorinated saturated hydrocarbon, those having 2 to 5 carbon atoms are preferable. More preferred are chlorinated aliphatic hydrocarbons. Examples include dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, isopentyl chloride and the like.
Among these, isopropyl chloride (also known as 2-chloropropane) is preferable because it has a low ozone depletion coefficient and is excellent in environmental compatibility.

  As the saturated hydrocarbon, those having 3 to 7 carbon atoms are preferable. For example, butane, isobutane, pentane, isopentane, cyclopentane, hexane, heptane, etc.).

  The foaming agent may further contain other foaming agents other than the above-mentioned halogenated unsaturated hydrocarbon, chlorinated saturated hydrocarbon, and saturated hydrocarbon as necessary. Other blowing agents include: fluorinated saturated hydrocarbons; low boiling point gases such as nitrogen, argon, carbon dioxide, air; sodium bicarbonate, sodium carbonate, calcium carbonate, magnesium carbonate, azodicarboxylic amide, azobisisobutyro Examples thereof include chemical foaming agents such as nitrile, barium azodicarboxylate, N, N′-dinitrosopentamethylenetetramine, p, p′-oxybisbenzenesulfonylhydrazide, trihydrazinotriazine; 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 weight, more preferably 3 to 15 parts by weight, and more preferably 5 to 11 parts by weight per 100 parts by weight of the phenol resin. Part is more preferred.
The proportion of halogenated unsaturated hydrocarbon in 100 parts by mass of the blowing agent is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and most preferably 50 parts by mass or more. 100 mass parts may be sufficient.

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 phenolic resin composition is the same as the composition of the foaming agent contained in the foam-cured phenol resin foam. It is almost coincident. The composition of the two or more foaming agents contained in the phenol resin foam can be confirmed, for example, by 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 retention time under the following measurement conditions with a gas chromatograph-mass spectrometer (GC / MS) is determined. 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 hydrocarbon is identified from the retention time and mass spectrum determined in advance. 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

<Additives>
(Acid catalyst)
The acid catalyst is contained in the foamable phenol resin composition in order to cure the phenol 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 individually by 1 type, and may be used in combination of 2 or more type.
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)
A surfactant may be contained in the foamable phenol resin composition. 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 alone or in combination of two or more.
It is preferable to use a surfactant having an HLB (Hydrophilic-Lipophilic Balance, also referred to as hydrophilic / lipophilic balance) of 8 to 18. When the HLB of the surfactant is within the above range, a phenol resin foam with little water absorption when the atmospheric humidity rises can be easily obtained. As for HLB of surfactant, 10-14 are more preferable. HLB in the case of using a mixture of a plurality of surfactants is a weighted average of the HLB 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 10 parts by mass, more preferably 2 to 5 parts by mass per 100 parts by mass of the phenol resin. preferable. If the content of the surfactant is not less than the lower limit of the above range, the cell diameter tends to be uniformly small, and if it is not more than the upper limit, the water absorption of the phenol resin foam is low and the production cost can be suppressed. .

  The surfactant used in the present invention is capable of detecting and quantifying the content in the phenol resin foam from a relatively low concentration to a high concentration by analysis with a measuring device described below.

  The first measuring device is a matrix-assisted laser desorption ionization-time-of-flight mass spectrometer (MALDI-TOF / MS). The analysis by this device is a soft ionization that irradiates the mixture of the matrix and measurement sample with laser light and ionizes the sample molecules through the matrix, so that the sample molecules can be ionized without being decomposed. The feature is that even high molecules can be measured.

  The next measuring apparatus is NMR. This apparatus is a measurement apparatus using nuclear magnetic resonance, and the position of a peak (chemical shift) measured depending on the chemical environment of the nuclide is different, so that the structure of the measurement substance can be specified. Further, since the molar ratio can be quantified from the integrated value of the peak, the surfactant used in the present invention can be quantified using an 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 phenol resin foam is cut out to a certain size, crushed with a pestle or mortar, and then used as a fine powder, using a Soxhlet extractor, about 1 gram of fine powder for about 8 hours, and the solvent in chloroform. Extract. The amount of the extract can be determined by drying the extract and measuring the weight. The dried product is measured with MALDI-TOF / MS. At this time, a sodium iodide / acetone solution can be used as an ionization aid, and a disulanol / chloroform solution can be used as a matrix.
For example, when measuring polyoxyethylene stearyl ether of alkyl group C18 with HLB = 17.6, the most frequent peak appears in the vicinity of 2010, and the peak interval is detected at about 44. Based on this detection state, the abundance can be estimated by the presence of polyoxyethylene alkyl ether and the height (strength) of the peak.

  Also, using the same dry sample as above, dissolving with deuterated chloroform solvent, and using dimethyl sulfoxide as an internal standard substance by NMR, for example, from 400 ppm and peak intensity appearing at 3.6 PPM at 400 MHz, Identify the amount of polyoxyethylene alkyl ether in the dried sample. When measuring the above-mentioned polyoxyethylene stearyl ether of alkyl group C18 with HLB = 17.6 from the phenol resin foam, components other than the surfactant are also extracted in Soxhlet extraction. The amount in the foam is determined using a calibration curve for the amount of surfactant added and the amount of surfactant in the Soxhlet extract. By measuring in this way, even if the content in the sample is extremely small, the amount of the surfactant present in the phenol resin foam can be measured with high accuracy.

(Other ingredients)
As other components, known additives for phenolic resin foams can be added to the foamable phenolic resin composition, such as urea, plasticizers, fillers, flame retardants (eg phosphorus-based flame retardants), Examples include a crosslinking agent, an organic solvent, an amino group-containing organic compound, a colorant, and a neutralizing agent.

<Manufacturing method>
The foamable phenol resin composition can be prepared by mixing the above-described components.
The mixing order of each component is not particularly limited. For example, a surfactant and other components are added to a phenol resin as necessary, and the whole is mixed, and a foaming agent and an acid catalyst are added to the mixture. Is supplied to a mixer and stirred to prepare a foamable phenolic resin composition.

The foamed phenolic resin composition 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, the foamable phenol resin composition is heated in a heating furnace to be foamed and cured (foaming / curing process), and further cured and dried in a dryer (post-curing / drying process) to obtain a phenol resin foam. The manufacturing method is preferred.

When producing a phenolic resin foam by foam molding, a face material may be provided.
The face material is not particularly limited, glass paper, glass fiber woven fabric, glass fiber nonwoven fabric, glass fiber mixed paper, kraft paper, synthetic fiber nonwoven fabric composed of fibers such as polyester, polypropylene, nylon, spunbond nonwoven fabric, At least one selected from aluminum foil-clad nonwoven fabric, aluminum foil-clad kraft paper, metal plate, metal foil, plywood, calcium silicate plate, gypsum board, and wood-based cement plate is preferred, and in particular, glass fiber mixed paper, Glass fiber nonwoven fabrics and synthetic fiber nonwoven fabrics are preferred because they are industrially available and easy to obtain. Among these, synthetic fiber nonwoven fabrics are preferable in that the texture and fluffing of the nonwoven fabric surface layer can be controlled by changing the heat fusion point pattern between the fibers with an embossed heating roll in production, and are easy to handle. Moreover, when the face material is a synthetic fiber nonwoven fabric, it is possible to suppress the occurrence of wrinkles due to shrinkage or the like of the face material due to moisture in the foamable phenolic resin composition or water generated during the condensation of the phenol resin.
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.

Basis weight of the surface material is not particularly limited, when using a synthetic fiber nonwoven fabric, the basis weight that is preferably, 15 g / ^{m 2} or more 150 g / ^{m 2} or less is 15 g / ^{m 2} or more 200 g / ^{m 2} or less it is more preferable, further preferably 15 g / ^{m 2} or more 100 g / ^{m 2} or less, particularly preferably at 20 g / ^{m 2} or more 80 g / ^{m 2} or less, 20 g / ^{m 2} or more 60 g / ^{m 2} or less Most preferably it is.
When glass fiber mixed paper is used, the basis weight 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. More preferably, it is 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 nonwoven fabric is used, the basis weight 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 more preferably 30 g / m ² or more and 150 g. / M ² or less is more preferable.
If the basis weight is equal to or more than the above lower limit value, the foamable phenolic resin composition is difficult to ooze on the surface of the face material. When the basis weight is not more than the above upper limit value, the adhesion between the foam and the face material can be enhanced. Thereby, a face material becomes difficult to peel from a foam, and the surface can be made beautiful. In addition, it becomes easy to follow a conveying device such as a conveyor, and it is easy to increase the productivity of the phenol resin foam. In particular, when the blowing agent contains a halogenated saturated hydrocarbon, a fluorinated unsaturated hydrocarbon (HFO), a chlorinated fluorinated unsaturated hydrocarbon, and cyclopentane, the foaming phenol resin composition can be obtained by containing the blowing agent. Viscosity decreases. When the viscosity of the composition is low, the composition is likely to ooze into the face material, and the composition is likely to ooze out to the surface of the face material. Thus, the composition can be prevented from oozing out.

When the face material is a glass fiber mixed paper, the content of the glass fiber relative to the basis weight of the face material is preferably 10% by mass to 90% by mass, and more preferably 30% by mass to 70% by mass. If the glass fiber content is equal to or higher than the lower limit, the flame retardancy of the phenolic resin foam plate can be further improved. When the glass fiber content is not more than the above upper limit, the peel strength between the phenolic resin foam plate and the face material can be sufficiently increased.
The remaining main component of the glass fiber mixed paper is cellulose fiber, and may further contain a binder, an inorganic filler, a colorant and the like.

When the face material is a synthetic fiber nonwoven fabric, it is preferable that so-called embossed (thermocompression-fixed portion) having a concavo-convex shape is formed. By using the face material on which the emboss is formed, the adhesion 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 from the viewpoint that the uneven shape by embossing is large and the adhesion to the foamed layer can be further improved.
In order to emboss the synthetic fiber nonwoven fabric, for example, by using a known spunbond method, a crimped long fiber web developed under cooling conditions immediately below the spinning nozzle is partially thermocompression bonded with a hot embossing roll, or It is produced by crimping the stretched fiber web by heat treatment and partially thermocompression bonding with a hot embossing roll.

In the heat crimped portion formed during embossing, the area per thermocompression fixing section 1 point is preferably 0.05 mm ² or more 5.0 mm ² or less, more preferably 0.07 mm ² or more 3.0 mm ² or less . By using the face material within this range, the adhesion between the foamable resin composition and the face material can be improved while suppressing the exudation of the foamable resin composition by the thermocompression-fixed portion. If the area is less than 0.05 mm ^2, less bonding between the fibers, the physical strength such as frictional strength tends to easily put bleeding less foamable resin composition, if it exceeds 5.0 mm ^2, the thermocompression bonding The area of the fixed part is large, the texture is hard, and the adhesiveness between the foamed resin layer and the fibers of the face material deteriorates. Furthermore, the Frazier permeability described later may be lowered, and the curing time may be prolonged, or the closed cell ratio may be reduced.
In general, the thermocompression-fixed portion can be easily found by visual observation or an optical microscope. The area of each thermocompression fixing portion can be measured by the following method.

<Ratio of the total area of fiber fixing parts>
An image obtained by enlarging the surface of the nonwoven fabric 10 times with an optical microscope was obtained. Using image processing software (trade name “Photoshop (registered trademark)”, manufactured by Adobe Systems Incorporated), the total area of the thermocompression-fixed portion included in a 100 mm long and 100 mm wide square (unit area) on the nonwoven fabric surface Was measured.

  The minimum distance between the thermocompression-fixed 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, the adhesion between the foamed resin layer and the face material can be improved while suppressing the seepage of the phenol resin. When the minimum distance is less than 0.05 mm, there are many thermocompression-fixed 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, there are few coupling | bonding of fibers, physical strength, such as friction strength, is low, and a foaming resin composition tends to ooze out. Moreover, it is preferable that the thermocompression-fixing part is evenly distributed over the entire surface of the nonwoven fabric surface.

Thermocompression fixed part density of 5 / cm ² or more 150 / cm ² or less, more preferably 5 / cm ² or more 50 / cm ² or less, is 5 / cm ² or more 30 / cm ² or less Further preferred. The thermocompression-fixed part density means the number of thermocompression-fixed parts per unit area and is represented by the following formula (s).
Thermocompression-fixed part density (pieces / cm ² ) = [Number of thermocompression-fixed parts (pieces)] / ”[Surface area (cm ² )] (s)
If the thermocompression-fixed partial density is not less than the above lower limit value, the exudation of the foamable resin composition can be satisfactorily suppressed. If the thermocompression-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 amount of water absorption can be reduced. Moreover, if the thermocompression-fixed partial density is not more than the above upper limit value, the Frazier air permeability described later can be increased, and the curing time can be shortened. Moreover, low thermal conductivity can be maintained over a longer period.

The fragile air permeability of the face material is preferably 60 cm ³ / cm ² · sec or more and 900 cm ³ / cm ² · sec or less, and preferably 100 cm ³ / cm ² · sec or more and 700 cm ³ / cm ² · sec or less. More preferably, it is particularly preferably 200 cm ³ / cm ² · sec or more and 500 cm ³ / cm ² · sec or less.
If the fragile air permeability of the face material is less than 60 cm ³ / cm ² · sec, the curing time in the curing process becomes longer, or the moisture generated in the curing process remains in the foamed layer, and the remaining moisture remains in the curing process When removed, it may become a pore and the closed cell ratio may be reduced.
A face material whose fragile air permeability of the face material exceeds 900 cm ³ / cm ² · sec has a remarkably small basis weight or a remarkably small thermocompression-fixed portion density. For this reason, the phenol resin composition discharged on the face material oozes out from the face material in the process of foaming and curing, and the manufacturing equipment is soiled. Further, moisture from the outside easily reaches the foamed layer, and the amount of water absorption increases.
The Frazier air permeability is a value calculated by measuring the amount of air passing through the face material using a Frazier type tester according to JIS L 1096, and is measured for the face material before being laminated on the foam layer. The

<Physical properties>
[density]
The density of the phenolic foam of the present invention is a 15~50kg / ^{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 compressive 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 density is adjusted by the type and composition of the foaming agent, the type of surfactant, foaming conditions (heating temperature, heating time, etc.), and the like.
A method for measuring the density will be described later.

[Average bubble diameter (cell diameter)]
The average cell diameter of the phenol resin foam of the present invention is 200 μm or less, preferably 50 μm to 200 μm, more preferably 50 μm to 150 μm, further preferably 50 μm to 120 μm, and most 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 surfactant, the foaming conditions (heating temperature, heating time, etc.) and the like.
A method for measuring the average bubble diameter will be described later.

[Closed cell ratio]
The closed cell ratio of the phenol resin foam of the present invention is 80% or more, preferably 85% or more, more preferably 90% or more, and may be 100%. When the closed cell ratio is equal to or higher than the lower limit, the heat insulating property of the phenol resin foam can be further improved.
The closed cell ratio is adjusted by a combination of the type or composition of the foaming agent, the type of surfactant, the foaming conditions (heating temperature, heating time, etc.) and the like.
A method for measuring the closed cell ratio will be described later.

[Surface resistivity]
The surface resistivity of the phenol resin foam of the present invention is 1 × 10 ¹² Ω / □ or less, preferably 1 × 10 ¹¹ Ω / □ or less, and more preferably 1 × 10 ¹⁰ Ω / □ or less. When the surface resistivity is less than or equal to the upper limit of the above range, chips are less likely to adhere, and the adhesion of chips is suppressed as the surface resistivity is lower. The lower limit of the surface resistivity is not particularly limited, but is preferably 1 × 10 ⁴ Ω / □ or more and more preferably 1 × 10 ⁵ Ω / □ or more in order to achieve a good balance with other physical properties.
The surface resistivity tends to decrease as the content of halogenated unsaturated hydrocarbon in the blowing agent increases. It is considered that the fact that the halogenated unsaturated hydrocarbon has polarity contributes to a decrease in surface resistivity.
A method for measuring the surface resistivity will be described later.

[Equilibrium moisture content]
The equilibrium water content of the phenol resin foam of the present invention is preferably 3 to 10% by mass, more preferably 3 to 8% by mass, and still more preferably 4 to 7% by mass. When the equilibrium moisture content is not less than the lower limit of the above range, a low surface resistivity can be easily obtained, and when it is not more than the upper limit, the heat insulation can be further improved. A method for measuring the equilibrium moisture content will be described later.

The equilibrium water content of the phenol resin foam can be adjusted by the conditions of the post-curing / drying process.
The post-curing / drying step is performed by adjusting the temperature and time in the curing furnace. When the heating temperature is in the range of 80 ° C. or higher and 90 ° C. or lower, it is preferably performed for 4.5 hours or longer and 12 hours or shorter. Moreover, it is preferable to carry out for 1 hour or more and less than 4.5 hours in the range whose heating temperature is 91 degreeC or more and 120 degrees C or less.
If it is less than the above lower limit value, it is in an undried state (drying is not sufficient), and post-curing is not completed. Gets worse. On the other hand, when the above upper limit is exceeded, heat drying proceeds too much, and not only does the bubbles burst and the closed cell rate decreases, but the equilibrium moisture content becomes too low, so that chips are generated when the phenol resin foam is cut. Cheap.
At this time, the structure of the hot air curing furnace is not particularly limited, and may be a single structure or a composite structure. A hot air curing furnace may be used as the curing furnace. In this case, the wind speed of the hot air is not particularly limited, but is usually 0.5 m / second or more, preferably 1 m / second or more. If this wind speed is less than 0.5 m / sec, it takes too much time for the post-curing treatment, resulting in poor productivity and difficulty in obtaining a phenol resin foam having predetermined physical properties.

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.
<Measurement method>
The measuring method of the physical property of a phenol resin foam is as follows.
[density]
A density measures the density of a phenol resin foam according to JIS A 9511: 2009.

[Average bubble diameter (cell diameter)]
A test piece is cut out from approximately the center in the thickness direction of the phenol resin foam. Photograph the cut surface in the thickness direction of the specimen at 50 times magnification. Draw four straight lines with a length of 9 cm on the captured image. At this time, a straight line is 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) is counted for each straight line, and the average value per straight line is obtained. 1800 μm is divided by the average value of the number of bubbles, and the obtained value is defined as the average bubble size.
[Closed cell ratio]
According to JIS K7138-2006, the closed cell ratio of the phenol resin foam is measured.
[Thermal conductivity]
The thermal conductivity is measured according to JIS A 1412-2.

[Surface resistivity]
The phenol resin foam is cut parallel to the thickness direction. The cutting position is 5 cm or more inside from the end face parallel to the thickness direction of the phenol resin foam. The surface resistivity of the cut surface immediately after cutting is measured using a surface resistivity meter (product name: Hiresta UP MCP-HT450, manufactured by Mitsubishi Chemical Corporation) at an applied voltage of 100V. However, when the surface resistivity is 1 × 10 ¹² Ω / □ or more, the applied voltage is measured at 1000V.

[Equilibrium 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 the mass of the phenol resin foam left in an atmosphere at a temperature of 23 ° C. and a relative humidity of 50% for 14 days was an initial mass. Let _m0 . The phenol resin foam is put into an oven at 104 ° C., the mass after 48 hours is defined as m _1, and the equilibrium water content (unit: mass%) is determined by the following formula (1).
Equilibrium moisture content = (m ₀ −m ₁ ) / m ₀ × 100 (1)

<Examples 1-7, Comparative Examples 1-5>
Using the foaming agents shown in Tables 1 and 2, phenol resin foams were produced by the following method. Tables 1 and 2 show the amount of the foaming agent used in each example with respect to 100 parts by mass of the phenol resin.
To 100 parts by mass of liquid resol type phenolic resin (Asahi Organic Materials Co., Ltd., trade name: PF-339), 4.5 parts by mass of castor oil EO adduct (30 addition moles, HLB = 11) as a surfactant, As a formaldehyde catcher agent, 4 parts by mass of urea was added and mixed, and allowed to stand at 20 ° C. for 8 hours.
The foaming agent shown in Tables 1 and 2 is added to 108.5 parts by mass of the mixture thus obtained, and 16 parts by mass of a mixture of paratoluenesulfonic acid and xylenesulfonic acid is added as an acid catalyst, followed by stirring and mixing. Thus, a foamable phenol resin composition was prepared.
A first face material (material: polyester nonwoven fabric, basis weight: 30 g / m ² , thermocompression-fixed partial density: 8 pieces / cm ² , fragile air permeability: 300 cm ³ 18 lines / cm ² · sec) at equal intervals in the direction perpendicular to the traveling direction (hereinafter also referred to as the length direction) of the first face material (hereinafter also referred to as the width direction). Ejected from the nozzle. A second face material (material: polyester nonwoven fabric) was stacked thereon. An uncured product in a state where the foamable phenol resin composition layer was sandwiched between the upper surface of the first face material and the lower surface of the second face material was formed.
The uncured product was foamed by heating at 70 ° C. for 300 seconds (foaming / curing step), and post-cured and dried at the heating temperature and time shown in Tables 1 and 2 (post-curing and drying step). Then, it cut | disconnected in the width direction 1820mm and the length direction 910mm, and manufactured the phenol resin foam with a face material of thickness 45mm.
The density, average cell diameter, closed cell rate, thermal conductivity, equilibrium moisture content, and surface resistivity level were measured by the above methods. The results are shown in Tables 1 and 2 (hereinafter the same).

<Examples 8 and 9>
Phenol with face material in the same manner as in Example 1 except that an alkyl ether surfactant (manufactured by Nikko Chemicals, product name “NIKKOL BB-20”, HLB = 16.5) was used as the surfactant. A resin foam was produced.

  As shown in the results of Tables 1 and 2, Examples 1 to 9 can reduce the surface resistivity as compared with Comparative Examples 1 to 5, and the physical properties of the phenolic resin foam such as thermal conductivity are also improved. It was good.

Claims (2)

It contains a phenolic resin and a halogenated unsaturated hydrocarbon, has a density of 15 to 50 kg / m ³ , an average cell diameter of 200 μm or less, a closed cell ratio of 80% or more, and a surface resistivity of 1 × 10 ¹² Ω / □. The phenol resin foam which is the following.   The phenol resin foam of Claim 1 whose equilibrium moisture content is 3-10 mass%.