JP2018095866A - Phenolic resin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phenolic resin foam having reduced water absorption when the atmospheric humidity rises.SOLUTION: A phenolic resin foam contains a phenolic resin and a halogenated hydrocarbon, with a density of 15-50 kg/m, an average cell diameter of 50-200 μm, a closed-cell ratio of 85% or more, and an equilibrium moisture content at temperature 23°C and relative humidity 50% of 6 mass% 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 building field, a phenol resin foam wallboard is employed as a synthetic resin building material, particularly a wallboard interior material.
The phenol resin foam is usually produced by foaming and curing a foamable phenol resin composition containing a phenol resin, a foaming agent, an acid catalyst (curing agent) 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).
It has also been proposed to use a halogenated unsaturated hydrocarbon having a zero ozone depletion coefficient, a small warming coefficient, and a low thermal conductivity as a foaming agent for a phenol resin foam (see Patent Document 2). .

Japanese Patent No. 4939784 Japanese Patent No. 5688487

Thermal insulation made of phenolic resin foam may be installed in an environment that tends to be humid, such as the base of a building, and even if the atmospheric humidity rises, the amount of water absorption of the thermal insulation does not increase and performance is stable. It is required to do.
An object of this invention is to provide the phenol resin foam with little water absorption when atmospheric humidity rises.

The present inventors have increased the water absorption amount of the phenol resin foam when a saturated hydrocarbon or an unsaturated hydrocarbon having a halogen atom is used, 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 moisture content at normal temperature of the phenol resin foam, it was found that when the equilibrium moisture content is low, there is little moisture inflow (absorption and desorption) in the phenol resin foam.

The present invention has the following aspects.
<1> A phenol resin and a halogenated hydrocarbon are contained, the density is 15 to 50 kg / m ³ , the average cell diameter is 50 to 200 μm, the closed cell rate 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 phenol resin foam according to <1>, wherein a difference 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% is 2% by mass or less.
<3> The phenol resin foam according to <1> or <2>, which contains isopropyl chloride as the halogenated saturated hydrocarbon.
<4> including one or both of 1,1,1,4,4,4-hexafluoro-2-butene and 1-chloro-3,3,3-trifluoropropene as the halogenated unsaturated hydrocarbon, The phenol resin foam according to any one of <1> to <3>.

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

The phenolic resin foam of the present invention includes a cured phenolic resin and a foaming agent. The blowing agent includes a halogenated 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, and an acid catalyst.
In the case of so-called heat insulation in the foundation where a heat insulating material is installed inside the foundation of the building, the moisture generated from the foundation becomes a problem of deterioration of the heat insulation performance in particular because it does not have a vent for exhausting moisture. Since the phenol resin foam of the invention has a low equilibrium moisture 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, the cross section can be provided on both the vertical part and the horizontal part on the indoor side of the substantially L-shaped foundation. It is installed so that the face material comes into contact.

<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 hydrocarbon. Further, it may contain a saturated hydrocarbon. Halogenated hydrocarbons can be broadly classified into halogenated saturated hydrocarbons and halogenated unsaturated hydrocarbons.
[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.

[Halogenated saturated hydrocarbon]
As a halogenated saturated hydrocarbon, a well-known thing can be used as a foaming agent, For example, fluorinated saturated hydrocarbon, chlorinated saturated hydrocarbon, etc. are mentioned. The halogenated saturated 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.
A halogenated saturated hydrocarbon may be used individually by 1 type, and may be used in combination of 2 or more type.

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 fluorinated saturated hydrocarbon, those having 1 to 5 carbon atoms are preferable. 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-pentafluoropropane (HFC245fa), 1,1,1,3,3-pentafluofane (HFC365mfc) and 1,1,1,2,2,3,4,5,5 , 5-decafluoropentane (HFC4310mee) and the like.

[Saturated hydrocarbon]
As the saturated hydrocarbon, those having 3 to 7 carbon atoms are preferable. Examples include butane, isobutane, pentane, isopentane, cyclopentane, hexane, heptane and the like.

  The blowing agent may further contain other blowing agents other than the above-mentioned halogenated unsaturated hydrocarbon, halogenated saturated hydrocarbon, and saturated hydrocarbon, if necessary. Other blowing agents include low boiling point gases such as nitrogen, argon, carbon dioxide and air; sodium bicarbonate, sodium carbonate, calcium carbonate, magnesium carbonate, azodicarboxylic acid amide, azobisisobutyronitrile, barium azodicarboxylate , N, N′-dinitrosopentamethylenetetramine, p, p′-oxybisbenzenesulfonyl hydrazide, chemical foaming agent such as 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 hydrocarbon in 100 parts by mass of the blowing agent is preferably, for example, 20 parts by mass or more, and more preferably 30 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)
It is preferable to include a surfactant 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, 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 8-18. 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 8 parts by mass, more preferably 3 to 5 parts by mass per 100 parts by mass of the phenol resin. preferable. If the surfactant content is not less than the lower limit of the above range, the bubble diameter tends to be uniformly small, and if it is not more than the upper limit, a phenol resin foam with less water absorption when the atmospheric humidity is increased can be obtained. Cheap.

  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 thereof include a crosslinking agent, an organic solvent, an amino group-containing organic compound, and a coloring 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, a foamed phenol resin composition is produced by heating and foaming and curing in a heating furnace (foaming / curing process), and further curing and drying in a dryer (curing / drying process). A discharge device, a foam molding device that is disposed downstream of the discharge device and performs a foaming / curing process, a cutting device disposed downstream of the foam molding device, and a curing / drying process. A manufacturing system including 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 material (foamable phenol resin composition). Is provided.
The foam molding apparatus includes a frame portion and heating means. A frame part is provided with the conveyor (a lower conveyor, an upper conveyor, a left conveyor, a right conveyor) arrange | positioned up and down, right and left so that the space corresponding to the cross-sectional shape of a phenol resin foam may be formed. Foaming in the vertical direction is regulated by the lower conveyor and the upper conveyor, and foaming in the horizontal direction is regulated by the left conveyor and the right conveyor. The foamable phenol resin composition passing through the frame portion is heated by the heating means, and is foamed and cured. Examples of the foam molding apparatus include those described in JP 2000-218635 A.
In addition, it is good also as an escape route of the water | moisture content which opens a through-hole in each conveyor and can discharge | release the water | moisture content generated during hardening outside.

  In this manufacturing system, first, the first face material is continuously supplied between the discharge device and the foam molding device. A foaming phenol resin composition is discharged onto the first face material from a plurality of nozzles by a discharge device. A second face material is placed thereon, introduced into the frame part of the foam molding apparatus, and heated at 30 to 95 ° C. Thereby, a foamable phenol resin composition foams and hardens | cures between a 1st face material and a 2nd face material, and a phenol resin foam is formed. This phenol resin foam is led out from the foam molding apparatus and cut into an arbitrary length by a cutting apparatus. Thereby, the 1st face material is provided in one surface, and the phenol resin foam by which the 2nd face material was provided in the other surface is obtained.

Subsequently, the cut phenol resin foam is stored in a curing box, and a curing / drying process is performed.
The curing / drying process is performed by adjusting the temperature and time in the curing chamber. 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.
By performing curing and drying within the above temperature and time range, it is possible to prevent coarsening of the bubble diameter and a decrease in the closed cell ratio, and to lower the equilibrium moisture content.

<Face material>
When producing a phenolic resin foam by foam molding, a face material may be provided. The face material and the foam layer are bonded together without an adhesive layer, and are directly joined to the face material by the joining force of the phenol resin itself constituting the foam layer.
The face material is not particularly limited, and glass paper, glass fiber woven fabric, glass fiber nonwoven fabric, glass fiber mixed paper, kraft paper, synthetic fiber nonwoven fabric, spunbond nonwoven fabric, aluminum foil tension nonwoven fabric, aluminum foil tension kraft paper, metal At least one selected from a board, a metal foil, a plywood board, a calcium silicate board, a gypsum board, and a wood cement board is suitable. In particular, a glass fiber mixed paper, a glass fiber nonwoven fabric, and a synthetic fiber nonwoven fabric are industrially distributed. Since the amount is large, it is easy to obtain and preferable. 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. Furthermore, since the face material made of a synthetic fiber nonwoven fabric is lower in water absorption than the face material containing cellulose fibers, the water absorption of the phenol resin foam can be further reduced.

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.
In addition, you may provide a face material by bonding together with a phenol resin foam using an adhesive agent after foam molding.

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 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 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.

  Although the thickness of a face material is not specifically limited, 0.06-1.00 mm is preferable and 0.10-0.50 mm is more preferable. When the thickness of the face material is equal to or more than the lower limit value, it is easy to suppress the bleeding of the face material to the surface. When the thickness of the face material is not more than the above upper limit value, the handleability of the face material is more excellent.

When the face material is a synthetic fiber nonwoven fabric, examples of the material of the synthetic fiber nonwoven 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.
Moreover, the fiber diameter of the synthetic fiber of the synthetic fiber nonwoven fabric is preferably 0.5 to 4.0 denier, and more preferably 1.5 to 3.0 denier.
When the fiber diameter of the synthetic fiber is equal to or less than the upper limit value, it is easy to suppress oozing to the surface of the face material.
When the fiber diameter of the synthetic fiber is equal to or greater than the lower limit, the handleability of the synthetic fiber is improved and it is easy to produce a nonwoven fabric.

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. Further, the air permeability may be lowered, the curing time may be increased, and the closed cell ratio may be reduced.

  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, the air permeability can be increased and the curing time can be shortened. Moreover, low thermal conductivity can be maintained over a longer period.

<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 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 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, for example, 85% or more, preferably 90% or more, more preferably 95% 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.

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

[Wet moisture content / moisture content difference]
As an index of the water absorption amount of the phenol resin foam when the atmospheric humidity is increased, 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% (this In the specification, it may be simply referred to as “moisture content difference”). It means that the smaller the moisture content difference, the smaller the amount of water absorption due to the increase in atmospheric humidity.
A method for measuring the wet moisture content will be described later.
The phenolic resin foam of the present invention has a wet moisture content of preferably 8% by mass or less, more preferably 7.5% by mass or less, and even more preferably 7% by mass or less. The lower the moisture content, the lower the water absorption when the humidity increases, and the better the performance stability.
The difference in moisture content of the phenol resin foam of the present invention is a value obtained by subtracting the equilibrium moisture content from the wet moisture content. The water content difference is preferably 2% by mass or less, more preferably 1.5% by mass or less, and further preferably 1% by mass or less. The lower the moisture content, the lower the water absorption when the humidity increases, and the better the performance stability.

<Action mechanism>
According to the present invention, even if the foaming agent contains a halogenated hydrocarbon, a phenol resin foam with less water absorption when the atmospheric humidity is increased can be obtained. The reason why the amount of water absorption of the phenol resin foam is likely to increase when a halogenated hydrocarbon is used rather than when an aliphatic hydrocarbon (alkane) is used as the blowing agent is considered as follows.
Since the halogenated hydrocarbon has high polarity and high compatibility with the phenol resin, the phenol resin is easily plasticized when the blowing agent contains the halogenated hydrocarbon. When the phenol resin is plasticized, a strong cell wall is not easily formed in the phenol resin foam, so that the foaming agent in the cells tends to be easily replaced with air. Such a phenol resin foam is likely to contain moisture under wet conditions, and the amount of water absorption of the foam increases, resulting in performance degradation.
Also, as shown in the examples described later, by changing the type of surfactant, the equilibrium moisture content at room temperature can be lowered, and the amount of water absorption (moisture content difference) when the atmospheric humidity rises. Can be small. The reason is considered to be that the solubility of the halogenated hydrocarbon in the phenol resin is changed by the action of the surfactant in the foamable phenol resin composition, and the plasticization of the phenol resin can be suppressed.

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.

[Equilibrium moisture content]
After 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, the mass of the phenol resin foam left in an atmosphere at a temperature of 23 ° C. and a relative humidity of 50% for 7 days was an initial mass. Let _m0 . The phenol resin foam is put into an oven at 104 ° C., and 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)

[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 allowed to stand for 7 days in an atmosphere at a temperature of 23 ° C. and a relative humidity of 50%. The mass of the phenol resin foam left in a 7% atmosphere for 7 days is defined as the initial mass k ₀ . The phenol resin foam is put into an oven at 104 ° C., and the mass after 48 hours is defined as k _1, and the wet moisture content (unit: mass%) is determined by the following formula (2).
Wet moisture content = (k ₀ −k ₁ ) / k ₀ × 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 Co., Ltd. “SURFRIC AQ-250”), HLB = 11.
Surfactant (2): Silicone surfactant (Shin-Etsu Silicone “KF-615A”), HLB = 10.
Surfactant (3): Silicone surfactant (Toray Dow Corning “SF-2945F”), HLB = 13.
Surfactant (4): Fluorosurfactant (AGC Seimi Chemical Co., “Surflon s-243”), HLB = 15.
Surfactant (5): Alkyl ether surfactant (Nikko Chemicals "NIKKOL BB-20"), HLB = 16.5
Surfactant (6): Fatty acid ester surfactant (Nikko Chemicals “NIKKOL MYS-40MV”), HLB = 17.5
Surfactant (7): Silicone surfactant (Toray Dow Corning “SH-193”), HLB = 19.
<Examples 1-8, 11, 12>
Examples 1 to 8 are examples, and examples 11 and 12 are comparative examples. The types of foaming agents used in each example (A to H in Table 1), the types of surfactants (above (1) to (7)) and the amount added are shown in Table 2 (the same applies hereinafter).

A phenol resin foam was produced by the following method.
A surfactant is added to 100 parts by mass of a liquid resol type phenolic resin (trade name: PF-339, manufactured by Asahi Organic Materials Co., Ltd.), and further 4 parts by mass of urea is added as a formaldehyde catcher agent and mixed. Left for 8 hours.
A foaming agent was added to the mixture thus obtained, 16 parts by mass of a mixture of p-toluenesulfonic acid and xylenesulfonic acid was added as an acid catalyst, and the mixture was stirred and mixed to prepare a foamable phenol resin composition. .
The foamable phenolic resin composition is continuously run on the first face material (material: glass fiber mixed paper, basis weight: 80 g / m ² ) running on the first face material (hereinafter referred to as “long”). The nozzles were ejected from 18 nozzles arranged at equal intervals in the vertical direction (hereinafter also referred to as the width direction). A second face material made of the same material as the first face material was stacked thereon. The uncured product in a state where 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 process) and drying at 80 ° C. for 5 hours in a curing chamber (curing / drying process), the resin is cut into a width direction of 1820 mm and a length direction of 910 mm, and a phenol resin with a face material having a thickness of 45 mm A foam was produced.
The density, average cell diameter, closed cell content, equilibrium water content, and wet water content were measured by the above methods, and the water content difference was determined. The results are shown in Table 2 (hereinafter the same).

<Example 9>
Example 9 is an example. A phenol resin foam was produced by the following method.
A foamable phenol resin composition was prepared in the same manner as in Example 1.
The foamable phenolic resin composition is continuously formed on the first face material (material: polyester nonwoven fabric, basis weight: 20 g / m ² , thermocompression-fixed partial density: 8 / cm ² ). The nozzles were ejected from 18 nozzles arranged at equal intervals in the width direction of the face material. A second face material made of the same material as the first face material was stacked thereon. The uncured product in a state where 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 process) and drying at 95 ° C. for 2 hours in a curing chamber (curing / drying process), the resin is cut into a width direction of 1820 mm and a length direction of 910 mm, and a phenol resin with a face material having a thickness of 45 mm A foam was produced.

<Example 10>
Example 10 is an example. A phenol resin foam was produced by the following method.
In Example 10, a phenol resin foam with a face material was produced in the same manner 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 moisture content was 6% by mass or less, a phenol resin foam having a small moisture content difference and less water absorption due to an increase in atmospheric humidity was obtained. The physical properties of the phenol resin foam were also good.
On the other hand, the phenol resin foams obtained in Examples 11 and 12 having an equilibrium moisture content exceeding 6% by mass had a large moisture content difference and a large amount of water absorption due to an increase in atmospheric humidity.

Claims (4)

Contains a phenolic resin and halogenated hydrocarbon, has a density of 15-50 kg / m ³ , an average cell diameter of 50-200 μm, a closed cell ratio of 85% or more, an equilibrium water content at a temperature of 23 ° C. and a relative humidity of 50%. A phenol resin foam in which is 6 mass% or less.   The phenol resin foam according to claim 1, wherein a difference 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% is 2 mass% or less.   The phenol resin foam according to claim 1 or 2, comprising isopropyl chloride as the halogenated saturated hydrocarbon.   The halogenated unsaturated hydrocarbon comprises one or both of 1,1,1,4,4,4-hexafluoro-2-butene and 1-chloro-3,3,3-trifluoropropene. The phenol resin foam as described in any one of -3.