JP7045169B2 - Phenol resin foam laminated board and its manufacturing method - Google Patents

Description

The present invention relates to a phenolic resin foam laminated board and a method for producing the same.

Among the organic resin foam laminates, the acid-curable phenol resin foam laminate made from resole-type phenol resin is particularly flame-retardant, heat-resistant, low-smoke, dimensional stability, solvent-resistant, and processed. Due to its excellent properties, it is widely used as various building materials such as exterior wall materials such as metal siding, inner wall materials such as partition panels, ceiling materials, fireproof doors, and shutters.

However, in the phenol resin foam laminated board, the inside of the foam tends to discolor as the days pass from the manufacturing date, and when the phenol resin foam laminated board of different manufacturing dates is cut out at the construction site and used together, the color difference on the cut surface There was a problem that the appearance was spoiled.

The mechanism of color change of the resol-type phenol resin over time is complicated, and it is known that, for example, dimethylol diphenoquinone produced by oxidative condensation of methylolated phenol in the resol-type phenol resin can be a factor. .. As a means for suppressing such a change in color with time, a method of modifying a phenolic hydroxyl group of a phenol resin with another substituent (Patent Document 1) and an antioxidant (for example, the substance described in Patent Documents 2 and 3). Is mentioned), and a method of adding is known.

However, when these methods are applied to the method for producing a resol-type phenol resin foam laminated board, there may be problems in physical properties such as deterioration of closed cell ratio, compressive strength, and brittleness due to poor curing reaction. Another problem is that manufacturing difficulties increase, such as harsher reaction conditions and an increase in the number of processes.

Japanese Unexamined Patent Publication No. 2004-269756 JP 2001-192373 Japanese Patent Application Laid-Open No. 10-81876

An object of the present invention is to provide a phenol resin foam laminated board in which the change in color inside the foam with time is improved without causing the above-mentioned problems.

In the present invention, in order to solve the above problems, the oxygen concentration in the synthesis step, the neutralization retention step, and the pre-foaming step in the manufacturing process of the phenolic resin foam laminated board is reduced to a specific amount or less. , It was found that the time-dependent change of the color inside the foam can be suppressed.

That is, the present invention provides the following [1] to [3].
[1]
It is a phenol resin foam laminated board in which face materials are arranged on at least the upper and lower surfaces of the phenol resin foam, and the phenol resin foam has a density of 10 kg / m ³ or more and 70 kg / m ³ or less and a closed cell ratio of 80. % Or more, and the color value X (L1 *, A1 *, B1 *) of the cut surface of the phenolic resin foam and the color value Y (L2) of the cut surface of the phenolic resin foam cut after heating at 100 ° C. for 24 hours. *, A2 *, B2 *) and color difference ΔE = {(L2 * -L1 *) ² + (A2 * -A1 *) ² + (B2 * -B1 *) ² } ^1/2 is 20.0 or less A phenolic resin foam laminated board characterized by being present.
[2]
The phenol resin foam laminate according to [1], wherein the phenol resin foam contains at least one selected from the group consisting of chlorinated hydrofluoroolefins and non-chlorinated hydrofluoroolefins.
[3]
A method for producing a phenol resin foam laminated board, wherein the oxygen concentration in each of the following steps (I) to (III) is 5% by volume or less.
(I) Synthesis step of synthesizing phenol resin using phenols and formaldehydes (II) Effervescence in the kneading step from the time when the pH of the phenol resin produced by the synthesis step is neutralized to 7.5 or less. Neutralization retention step of storing the phenol resin until the time when all the raw materials constituting the phenol resin composition are added (III) The lower surface of the effervescent phenol resin composition is distributed and widened by a plurality of discharge nozzles. Pre-foaming process of discharging onto the material and covering with the top material

According to the present invention, it is possible to obtain a phenol resin foam laminated board in which the color inside the foam does not easily change with time.

Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments.

The phenol resin foam laminate in the present embodiment is provided on at least the upper and lower surfaces of the phenol resin foam, which is present in a state in which a large number of bubbles are dispersed in the phenol resin formed by the curing reaction, and the phenol resin foam. It is equipped with a face material that has been removed. Further, the phenolic resin foam laminated board of the present embodiment has a small change in color over time inside the foam, and there is no color difference even when the phenolic resin foam laminated boards of different manufacturing dates are used in combination, and the appearance is apparent. It doesn't matter. Further, the phenolic resin foam laminated board of the present embodiment has a high closed cell ratio and has excellent long-term heat insulating performance. In addition, the phenolic resin foam laminated board of the present embodiment has excellent mechanical strength and can be suitably used for heat insulating applications. The thickness direction in the present embodiment refers to the dimension of the shortest side of the three sides of the foam laminated board. The thickness direction in the present embodiment is usually the direction in which the foamable phenol resin composition on the lower surface material foams and grows during the production of the foam laminate, and the thickness of the phenol resin foam laminate in the present embodiment is , 20 mm or more is targeted.

Further, the phenol resin foam laminated board is used for various purposes by using it alone or by joining it with an external member. Examples of the external member include a board-shaped material, a sheet-shaped / film-shaped material, and the like. Board-like materials include ordinary plywood, structural plywood, particle board, OSB, and other wood-based boards, as well as wood wool cement board, wood piece cement board, gypsum board, flexible board, medium density fiber board, and calcium silicate board. , Magnesium silicate plate, volcanic vitreous multi-layer plate and the like are suitable. The sheet-like and film-like materials include polyester non-woven fabric, polypropylene non-woven fabric, inorganic-filled glass fiber non-woven fabric, glass fiber non-woven fabric, paper, calcium carbonate paper, polyethylene-processed paper, polyethylene film, plastic moisture-proof film, asphalt waterproof paper, and aluminum. Foil (with or without holes) or the like is suitable.

The density of the phenol resin foam of the phenol resin foam laminate of the present embodiment is 10 kg / m ³ or more and 70 kg / m ³ or less, preferably 15 kg / m ³ or more and 50 kg / m ³ or less, more preferably 20 kg / m 3. It is m ³ or more and 40 kg / m ³ or less. When the density is 10 kg / m ³ or more, the decrease in mechanical strength such as the compressive strength in the thickness direction is suppressed, and the foam is less likely to be damaged during handling. In addition, the amount of air diffused into the phenol resin foam is reduced, and the change in color inside the foam with time can be suppressed. When the density is 70 kg / m ³ or less, there is no possibility that the heat transfer of the resin portion will increase and the heat insulating performance will deteriorate. The density of the phenolic resin foam can be adjusted to a desired value mainly by changing the ratio of the foaming agent and the curing conditions.

The closed cell ratio of the phenolic resin foam of the present embodiment is 80% or more, more preferably 90% or more. When the closed cell ratio is 80% or more, the replacement of the foaming agent in the phenol resin foam with air is suppressed, and the deterioration of the heat insulating performance can be suppressed. In addition, the amount of air replaced from the communicating bubbles is reduced, and the change in color inside the foam with time can be suppressed. The closed cell ratio of the phenolic resin foam can be adjusted to a desired value by changing, for example, the amount of the foam nucleating agent added, the curing conditions, and the like.

The average cell diameter of the phenolic resin foam of the present embodiment is preferably 20 μm or more and 200 μm or less, and more preferably 40 μm or more and 150 μm or less. When the average bubble diameter is 20 μm or more, the thickness of the bubble wall is kept within a certain range, the density increase due to the thickening of the bubble wall is suppressed, and as a result, the heat transfer of the resin portion is increased and the heat insulating performance is improved. It can be prevented from decreasing. Further, when the average bubble diameter is 200 μm or less, heat conduction due to radiation is not increased, and deterioration of heat insulating performance can be prevented. The average cell diameter of the phenolic resin foam can be adjusted to a desired value by changing, for example, the amount of the foam nucleating agent added, the curing conditions, and the like.

The color difference ΔE of the cut surface of the phenolic resin foam of the present embodiment before and after heat treatment at 100 ° C. for 24 hours is 20.0 or less, more preferably 16.0 or less, still more preferably 14.0 or less. Is. When the color difference ΔE is 20.0 or less, it is possible to suppress the time-dependent change in the color inside the foam of the phenol resin foam laminated plate. The method for evaluating the color difference ΔE will be specifically described in Examples described later.

The phenolic resin foam of the present embodiment is produced from an effervescent phenolic resin composition containing, for example, a phenolic resin, a surfactant, a foaming agent, a foaming nucleating agent, and an acidic curing agent. The effervescent phenol resin composition may optionally contain components other than the above.

A particularly important point in the method for producing the phenol resin foam laminated plate of the present embodiment is to prevent oxygen from being mixed into the phenol resin or the foamable phenol resin composition during the production. When the amount of oxygen mixed in the phenol resin or the foamable phenol resin composition is large, the amount of oxygen mixed in the phenol resin foam of the produced phenol resin foam laminate becomes large. The oxygen causes oxidative condensation of the methylolated phenol in the phenol resin foam over time, and the color change inside the foam becomes large with time. As will be described later, the method for producing a phenolic resin foam laminated plate of the present embodiment includes at least a synthesis step, a neutralization holding step, a kneading step, a pre-foaming step, a preforming step, and a main molding step. As a result of diligent studies, it was found that by reducing the oxygen concentration at least in the synthesis step, the neutralization retention step, and the pre-foaming step, the time-dependent change in the color inside the foam of the phenol resin foam laminated plate can be suppressed.

The means for reducing the oxygen concentration in each manufacturing process in the method for manufacturing a phenolic resin foam laminate of the present embodiment is not particularly limited, but for example, the inside of the apparatus used in each manufacturing process is replaced with a gas other than oxygen. The method can be mentioned. In this case, the type of gas used is preferably an inert gas such as nitrogen or argon from the viewpoint of explosion proof.

The oxygen concentration in the synthesis step, the neutralization retention step, and the pre-foaming step of the method for producing the phenolic resin foam laminate of the present embodiment is 5% or less, preferably 3% or less, more preferably 2% or less, and particularly. It is preferably 1% or less. When the oxygen concentration is 5% or less, the amount of oxygen mixed in the phenol resin or the effervescent phenol resin composition can be reduced in each step. The method for evaluating the oxygen concentration in each step will be specifically described in Examples described later.

(Synthesis process)
The method for producing a phenol resin foam laminated board of the present embodiment includes at least a synthesis step of synthesizing a phenol resin using phenols and formaldehydes.

As the phenol resin, a resol type phenol resin synthesized by an alkali metal hydroxide or an alkaline earth metal hydroxide is used. A resol-type phenol resin is synthesized by heating a phenol and an aldehyde as raw materials in a temperature range of 40 to 100 ° C. with an alkaline catalyst. Further, if necessary, an additive such as urea may be added during or after the synthesis of the resol type phenol resin. When adding urea, it is more preferable to mix urea that has been methylolated with an alkaline catalyst in advance with the resol type phenol resin.

The starting molar ratio of phenols to aldehydes during the synthesis of the phenolic resin is preferably in the range of 1: 1 to 1: 4.5, more preferably in the range of 1: 1.5 to 1: 2.5. ..

Here, the phenols preferably used in the synthesis of the phenolic resin in the present embodiment are phenol itself and other phenols, and examples of other phenols include resorcinol, catechol, o-, and m-. And p-cresol, xylenols, ethylphenols, p-tert butylphenol and the like. Also, dinuclear phenols can be used.

Further, the aldehydes may be any compound that can be an aldehyde source, and it is preferable to use formaldehyde itself, other aldehydes or derivatives thereof as the aldehydes. Examples of other aldehydes include glyoxal, acetaldehyde, chloral, furfural, benzaldehyde and the like.

Examples of the additive added to the phenol resin include dicyandiamide and melamine in addition to the above-mentioned urea.

The equipment used in the synthesis step of the present embodiment has a function of reducing the oxygen concentration of various raw materials used for the synthesis of the phenol resin and the gas portion in contact with the phenol resin in the synthesis step. The means is not particularly limited, but for example, a gas outlet is provided in the upper part of the equipment, a gas inlet is provided in the lower part of the equipment, and an internal oxygen is discharged by allowing a gas other than oxygen to flow from the lower part into the equipment. There is a structure that makes it possible to expel more.

(Neutralization retention process)
In the method for producing the phenolic resin foam laminated plate of the present embodiment, the foaming phenolic resin composition is formed in the kneading step described later from the time when the pH becomes 7.5 or less by adding an acid to the phenolic resin produced in the synthesis step. It includes at least a neutralization retention step of storing the phenolic resin until the time when all the raw materials constituting the product are added.

The acid added to the phenolic resin in the neutralization retention step is optional, for example, toluene sulfonic acid, xylene sulfonic acid, phenol sulfonic acid, substituted phenol sulfonic acid, xylenol sulfonic acid, substituted xylenol sulfonic acid, dodecylbenzene sulfonic acid, Examples include benzenesulfonic acid, naphthalenesulfonic acid, and hydrates thereof. The amount of the acid added varies depending on the type, and when paratoluenesulfonic acid monohydrate is used, it is 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the reaction solution at the completion of the synthesis step. It is preferable to have.

The pH of the phenol resin during the neutralization retention step is 5.0 or more and 7.5 or less.

The temperature of the phenol resin in the neutralization retention step is preferably 70 ° C. or lower.

The end point of the neutralization retention step is the time when all the raw materials constituting the effervescent phenol resin composition are added in the kneading step described later.

The duration of the neutralization retention step is preferably 10 days or less, more preferably 7 days or less, still more preferably 5 days or less. When the period of the holding step is 10 days or less, the amount of oxygen mixed in the phenol resin can be reduced.

The equipment used in the neutralization retention step of the present embodiment has a function of reducing the oxygen concentration of the gas portion in contact with the phenol resin during storage in the neutralization retention step. The means is not particularly limited, but for example, a gas outlet is provided in the upper part of the equipment, a gas inlet is provided in the lower part of the equipment, and an internal oxygen is discharged by allowing a gas other than oxygen to flow from the lower part into the equipment. There is a structure that makes it possible to expel more.

In the neutralization retention step of the present embodiment, a dehydration step of evaporating the water content in the phenol resin by vacuum dehydration may be provided, if necessary, for the purpose of adjusting the water content of the synthesized phenol resin. The temperature of the phenol resin in the dehydration step is preferably 70 ° C. or lower from the viewpoint of suppressing the oxidation of the phenol resin.

(Kneading process)
In the method for producing a phenol resin foam laminated board of the present embodiment, a phenol resin that has undergone a synthesis step and a neutralization retention step is kneaded with a surfactant, an acidic curing agent, a foaming agent, and a foam nucleating agent to form a foaming phenol resin. It comprises at least a kneading step to obtain the composition. The surfactant, foaming agent and foaming nucleating agent contained in the effervescent phenol resin composition may be added in advance to the phenol resin or may be added at the same time as the acidic curing agent. Further, it is more preferable that the oxygen concentration in the equipment used in the kneading step is low.

As the surfactant, those generally used for producing phenolic resin foams can be used, but among them, nonionic surfactants are effective, for example, alkylene which is a copolymer of ethylene oxide and propylene oxide. Oxides, condensates of alkylene oxides and castor oil, condensation products of alkylene oxides with alkylphenols such as nonylphenol and dodecylphenol, polyoxyethylene alkyl ethers with 14 to 22 carbon atoms in the alkyl ether moiety, and more. Fatty ester such as polyoxyethylene fatty acid ester, silicone compound such as polydimethylsiloxane, polyalcohol and the like are preferable. These surfactants may be used alone or in combination of two or more. The amount used is not particularly limited, but is preferably used in the range of 0.3 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the phenol resin.

The foaming agent is not particularly limited, but it is preferable to use hydrocarbons (HCs), hydrofluorocarbons (HFCs), chlorinated hydrofluoroolefins, non-chlorinated hydrofluoroolefins, chlorinated hydrocarbons and the like. From the viewpoint of preventing the destruction of the ozone layer, it is preferable to use hydrocarbons, hydrofluorocarbons and the like. In particular, it is more preferable to use hydrocarbons because of their small global warming potential. Further, from the viewpoint of further improving the heat insulating performance of the phenol resin foam laminated board, it is preferable to contain at least one selected from the group consisting of chlorinated hydrofluoroolefins and non-chlorinated hydrofluoroolefins.

As the hydrocarbon, cyclic or chain-shaped alkanes, alkanes, and alkynes having 3 to 7 carbon atoms are preferable, and specifically, normalbutane, isobutane, cyclobutane, normalpentane, isopentane, cyclopentane, neopentane, normal hexane, and the like. Examples thereof include isohexane, 2,2-dimethylbutane, 2,3-dimethylbutane, cyclohexane, and the like. Among them, normal pentane, isopentane, cyclopentane, neopentane pentane and normal butane, isobutane, cyclobutane butane are preferably used. Examples of the hydrofluorocarbon include hydrofluoropropene, hydrochlorofluoropropene, hydrobromofluoropropene, hydrofluorobutene, hydrochlorofluorobutene, hydrobromofluorobutene, hydrofluoroethane, hydrochlorofluoroethane, and hydrobromofluoroethane. Can be mentioned.

Specific examples of the chlorinated hydrofluoroolefin include 1-chloro-3,3,3-trifluoropropene (for example, manufactured by Honeywell Japan Co., Ltd., product name: Solstice ™ LBA). Specific examples of the non-chlorinated hydrofluoroolefin include 1,3,3,3-tetrafluoro-1-propene (for example, manufactured by Honeywell Japan Co., Ltd., product name: Solstice ™ 1234ze), 2 , 3,3,3-Tetrafluoro-1-propene, 1,1,1,4,4,4-hexafluoro-2-butene and the like.

Here, the content ratio of the chlorinated hydrofluoroolefin and the non-chlorinated hydrofluoroolefin in the foaming agent is preferably 30% by mass or more in order to exhibit the desired heat insulating performance without increasing the environmental load. , 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more.

As the chlorinated hydrocarbon, a linear or branched chlorinated aliphatic hydrocarbon having 2 to 5 carbon atoms can be used. The number of bonded chlorine atoms is not limited, but is preferably 1 to 4, and examples of the chlorinated aliphatic hydrocarbon include dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, and pentyl. Examples include chloride and isopentyl chloride. Of these, propyl chloride and isopropyl chloride, which are chloropropanes, are more preferably used.

These foaming agents may be used alone or in combination of two or more, and may be arbitrarily selected.

The amount of the foaming agent used varies depending on the type of foaming agent, compatibility with the phenol resin, and loss in the foaming / curing process, but is 3.0 parts by mass or more and 11.5% by mass with respect to 100 parts by mass of the phenol resin. The amount is preferably 4.0 parts by mass or more and 9.5 parts by mass or less. When the amount of the foaming agent with respect to the phenol resin is 3.0 parts by mass or more, the density does not become too high, which is preferable. Further, when the amount of the foaming agent with respect to the phenol resin is 11.5 parts by mass or less, the density does not become too low, which is preferable.

As the foaming nucleating agent, a low boiling point substance having a boiling point of 50 ° C. or higher lower than that of the foaming agent, such as nitrogen, helium, argon, and air, can be added. In addition, as a solid foam nucleating agent, aluminum hydroxide powder, aluminum oxide powder, calcium carbonate powder, talc, clay (kaolin), silica stone powder, silica sand, mica, calcium silicate powder, wallastnite, glass powder, glass Inorganic powders such as beads, fly ash, silica fume, gypsum powder, hosand, slag powder, alumina cement and Portoland cement, and organic powders such as crushed powder of phenol resin foam can also be added. These may be used alone or in combination of two or more.

The amount of the foaming nucleating agent added to the foaming agent is preferably 0.1% by mass or more and 0.4% by mass or less, preferably 0.2% by mass or more and 0.4% by mass, assuming that the amount of the foaming agent is 100% by mass. The following is more preferable. If the amount of the foam nucleating agent added is less than 0.1% by mass, non-uniform foaming tends to occur and the average cell diameter becomes too large, which is not preferable. Further, when the addition amount of the effervescent nucleating agent is more than 0.4% by mass, the effervescent phenol resin composition is too foamed, so that the effervescent phenol resin composition does not easily permeate into the face material, and the face material becomes difficult. It is not preferable because it easily peels off from the phenol resin foam.

The acidic curing agent may be any acidic curing agent capable of curing the effervescent phenol resin composition, and contains an organic acid as an acid component. As the organic acid, aryl sulfonic acid or an anhydride thereof is preferable. Examples of the aryl sulfonic acid and its anhydride include toluene sulfonic acid, xylene sulfonic acid, phenol sulfonic acid, substituted phenol sulfonic acid, xylenol sulfonic acid, substituted xylenol sulfonic acid, dodecylbenzene sulfonic acid, benzene sulfonic acid, naphthalene sulfonic acid and the like. And their anhydrides are mentioned, and these may be used alone or in combination of two or more. In this embodiment, resorcinol, cresol, saligenin (o-methylolphenol), p-methylolphenol and the like may be added as a curing aid. Further, these curing agents may be diluted with a solvent such as ethylene glycol and diethylene glycol.

The amount of the acidic curing agent used varies depending on the type, and when a mixture of 60% by mass of paratoluenesulfonic acid monohydrate and 40% by mass of diethylene glycol is used, a total of 100 of the phenol resin and the surfactant. It is preferably used in an amount of 8 parts by mass or more and 20 parts by mass or less, and more preferably 10 parts by mass or more and 15 parts by mass or less with respect to parts by mass.

(Pre-foaming process, pre-molding process, main molding process)
In the method for producing a phenol resin foam laminated plate of the present embodiment, after the resol synthesis step, the neutralization holding step, and the kneading step, the foamable phenol resin composition is distributed and widened by a plurality of ejection nozzles and traveled. A pre-foaming step of discharging onto the bottom surface material and covering with the top surface material, a preforming step of leveling and molding the foamable phenol resin composition coated with the upper and lower surface materials from the vertical direction, and foaming and foaming after the preforming step. It includes at least the main molding step of forming into a plate shape while advancing the curing.

As the face material arranged on at least the upper and lower surfaces of the phenol resin foam, a flexible face material (flexible face material) is used. The flexible surface materials used include non-woven fabrics and woven fabrics whose main components are polyester, polypropylene, nylon, etc., kraft paper, glass fiber mixed paper, calcium hydroxide paper, aluminum hydroxide paper, magnesium silicate paper, etc. Papers, non-woven fabrics of inorganic fibers such as non-woven fabrics of glass fibers, and the like are preferable, and these may be mixed (or laminated) and used. Above all, when the face material is peeled off from the obtained phenol resin foam laminated board and only the base material is used, inexpensive papers that can be discarded after the peeling are preferable. These facing materials are usually provided in the form of rolls. Further, as the flexible surface material, a material kneaded with an additive such as a flame retardant may be used. The method of adhering the face material to the phenol resin foam is not particularly limited, and the adhesive force of the phenol resin foam when it is thermally cured on the surface of the face material or an adhesive such as epoxy resin is used. It doesn't matter what you do.

The pre-foaming step is from the time when the foaming phenol resin composition discharged by the nozzle comes into contact with the traveling lower surface material to just before the foaming phenol resin composition is leveled when viewed from the vertical direction in the preforming step. Say the point in time. The number of discharge nozzles used to discharge the foamable phenol resin composition in the pre-foaming step is preferably 40 / m or less, more preferably 30 / m or less, still more preferably 20. / M, particularly preferably 15 lines / m or less. When the number of discharge nozzles per unit discharge width is 40 / m or less, the thickness of the strip-shaped foamable phenol resin composition (hereinafter referred to as "bead") discharged onto the lower surface material running from each nozzle. Is not too thin, so that the contact area between the effervescent phenol resin composition and oxygen can be reduced, and the amount of oxygen mixed in the effervescent phenol resin composition can be reduced.

Further, when a highly polar substance such as a chlorinated hydrofluoroolefin or a non-chlorinated hydrofluoroolefin is used as the foaming agent, due to the high compatibility of these foaming agents with the phenol resin, in the pre-foaming step. The effervescent phenolic resin composition tends to decrease in viscosity. When the effervescent phenol resin composition has a low viscosity, the initial foaming of the effervescent phenol resin composition tends to be delayed, and as a result, the volume of the resin composition decreases and the contact area with oxygen increases. Oxygen is likely to be mixed in the effervescent phenol resin composition. For these reasons, when highly polar substances such as chlorinated hydrofluoroolefins and non-chlorinated hydrofluoroolefins are used as foaming agents, reducing the oxygen concentration in the pre-foaming step is the color inside the foam. It is important for producing a phenol resin foam laminated board that suppresses the change with time.

The equipment used in the pre-foaming step of the present embodiment has a function of reducing the oxygen concentration of the gas portion to which the foaming phenol resin composition comes into contact in the pre-foaming step. The means thereof is not particularly limited, but for example, the entire pre-foaming process equipment (the lower surface material, the upper surface material portion, and the discharging portion of the foamable phenol resin composition running in the pre-foaming process) is sealed with an acrylic plate or the like, and the means thereof is sealed. A structure that has a gas outlet at the top of the enclosed space and a gas inlet at the bottom, allowing gas other than oxygen to flow from the bottom into the space to expel internal oxygen from the outlet. , Can be mentioned.

In the preforming step, various methods depending on the manufacturing purpose, such as a method using a slat type double conveyor, a method using a metal roll or a steel plate, and a method using a plurality of these in combination, can be mentioned. Of these, for example, in the case of molding using a slat type double conveyor, the effervescent phenol resin composition coated with the upper and lower facing materials is continuously guided into the slat type double conveyor and then heated while being heated. It can be foamed and cured while being adjusted to a predetermined thickness by applying pressure from the vertical direction, and can be formed into a plate shape.

In this forming step, a method using an endless steel belt type double conveyor, a slat type double conveyor, a roll or the like can be mentioned. Further, the residence time of this molding step is preferably 5 minutes or more and 2 hours or less because it is the main step of performing the foaming and curing reaction. When the residence time is 5 minutes or more, foaming and curing can be sufficiently promoted. Further, when the foaming and curing of the effervescent phenol resin composition is completed to some extent, the characteristics of the obtained phenol resin foam laminated board hardly change. Therefore, if the residence time is within 2 hours, the production efficiency of the phenol resin foam laminated board can be improved.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

First, a method for preparing the phenolic resins A to F used in Examples and Comparative Examples will be described.

(Preparation of phenolic resins A to F)
<Synthesis process>
In advance, a gas outlet is provided in the upper part of the reactor so that the internal pressure of the reactor does not rise, and then nitrogen gas (purity) from the lower part of the reactor until the oxygen concentration in the reactor reaches the value shown in Table 1. 99.9% by volume or more) was circulated inside and replaced. Next, 3500 kg of 52% by mass formaldehyde aqueous solution (52% by mass formalin) and 2510 kg of 99% by mass phenol (including water as impurities) were charged in the reactor, stirred by a propeller rotary stirrer, and inside the reactor by a temperature controller. The liquid temperature was adjusted to 40 ° C. Then, the temperature was raised while adding a 50% by mass sodium hydroxide aqueous solution to carry out the reaction. When the Ostwald viscosity reached 60 centistokes (60 × 10-6 m ² / s, measured value at 25 ° C.), the reaction solution was cooled and 570 kg of urea (corresponding to 15 mol% of the amount of formaldehyde charged) was added. ..

<Neutralization retention process>
Next, after providing a gas discharge port in the upper part of the holding tank in advance so that the internal pressure of the holding tank does not rise, nitrogen is added from the lower part of the holding tank until the oxygen concentration in the holding tank reaches the value shown in Table 1. Gas (purity; 99.9% by volume or more) was circulated inside and replaced. Then, the reaction solution prepared in the synthesis step was transferred from the reactor to the holding tank. Then, after cooling the reaction solution to 30 ° C., the pH was neutralized to 6.3 with a 50% by mass aqueous solution of p-toluenesulfonic acid monohydrate. This liquid was immediately dehydrated at 60 ° C. by a vacuum dehydrator, and the water content and the viscosity at 40 ° C. were measured. As a result, the water content was 7.8% by mass and the viscosity was 21000 mPa · s. The liquid thus obtained was kept at a temperature of 1 ° C. for 4 days.

Next, a method for producing the phenolic resin foam laminated board in Examples and Comparative Examples will be described.

(Examples 1 to 13, Comparative Examples 1 to 7)
<Kneading process>
For 100 parts by mass of each phenol resin, 3.0 parts by mass of a block copolymer of ethylene oxide-propylene oxide (manufactured by BASF, Pluronic F-127) as a surfactant, and 6 foaming agents having the compositions shown in Table 2. 8.8 parts by mass, 0.3% by mass of nitrogen as a foaming nucleating agent was added to the foaming agent, and 13 parts by mass of a mixture of 80% by mass of xylene sulfonic acid and 20% by mass of diethylene glycol was added as an acidic curing agent. The effervescent phenolic resin composition was supplied to the mixing head of the mixer.

<Pre-foaming process>
Next, in order to prevent the internal pressure of the pre-foaming process equipment sealed with an acrylic plate from rising in advance, a gas discharge port is provided at the top of the sealed space, and the oxygen concentration in the pre-foaming process equipment is shown in the table. Nitrogen gas (purity; 99.9% by volume or more) was circulated inside from the bottom of the closed space until the value shown in 2 was obtained, and the mixture was replaced. After that, the effervescent phenol resin composition kneaded with the mixing head is placed on the moving lower surface material through the multi-port piping at a flow rate of 40 kg / hr so that the total width of the discharge portion of the effervescent phenol resin composition is 1000 mm. Discharged. The distribution unit has 32 nozzles at the tip and is designed so that the mixed effervescent phenolic resin composition is uniformly distributed. As the upper and lower surface materials, glass fiber mixed paper (weight: 140 g / m ² ) or Eltus E05030 (weight: 30 g / m ² ), which is a polyester non-woven fabric manufactured by Asahi Kasei Corporation, is used as shown in Table 2. did.

<Pre-molding process, main molding process>
In order to prevent the internal pressure of the slat type double conveyor used in the main molding process from rising in advance, a gas discharge port is provided at the top of the conveyor, and the oxygen concentration in the main molding process equipment is the value shown in Table 2. Until then, nitrogen gas (purity; 99.9% by volume or more) was circulated and replaced in the conveyor. Next, through the previous step, the foamable phenol resin composition coated with the upper and lower surface materials was preformed from above the upper surface material with a free roller. The height of the free roller was adjusted to a position that was 2/3 of the thickness of the bead immediately after ejection (height in the direction perpendicular to the traveling direction of the face material). After that, it was sandwiched between the upper and lower facing materials, introduced into a slat type double conveyor heated to 83 ° C, cured with a residence time of 20 minutes (main molding step), and then cured in an oven at 110 ° C for 3 hours. Then, a phenol resin foam laminated board having a thickness of 50 mm was obtained. In the slat type double conveyor, the slat type double conveyor was formed into a plate shape by applying appropriate pressure from above and below through the face material.

Each evaluation item in Examples and Comparative Examples was measured by the following method.

(1) Oxygen concentration For the synthesis process, neutralization retention process, pre-foaming process, and main molding process, an oxygen concentration detector (GBL-OX-AX manufactured by Ichinenjiko Co., Ltd.) is installed at the gas outlet provided at the top of the equipment. Then, the oxygen concentration was measured.

(2) Moisture content The water content in the phenol resin was measured using a Karl Fischer Moisture Meter MKA-510 (manufactured by Kyoto Electronics Manufacturing Co., Ltd.).

(3) Viscosity Using a rotational viscometer (manufactured by Toki Sangyo Co., Ltd., R-100 type, rotor part is 3 ° x R-14), the measured value after stabilizing at 40 ° C for 3 minutes is the phenol resin. The viscosity was used.

(4) A phenol resin foam laminated board having a density of 20 cm square was used as a sample, and after removing the face material from this sample, the mass and the apparent volume were measured and determined according to JIS K7222.

(5) Closed cell ratio Measured according to ASTM-D-2856. Specifically, after removing the face material from the phenolic resin foam laminate, a cylindrical sample with a diameter of 35 mm to 36 mm is hollowed out with a cork borer, trimmed to a height of 40 mm or less, and then an air comparative hydrometer. The sample volume was measured by the standard usage method of a meter (manufactured by Tokyo Science Co., Ltd., type 1,000). The value obtained by subtracting the volume of the wall (part other than bubbles and voids) calculated from the sample mass and the density of the phenol resin from the sample volume divided by the apparent volume calculated from the outer dimensions of the sample is divided by the phenol resin. The closed cell ratio of the foam was used. Here, the density of the phenol resin was set to 1.3 kg / L.

(6) Average bubble diameter The average bubble diameter was measured by the following method with reference to the method described in JIS K6402. A 50-fold magnified photograph of the cut surface of the test piece obtained by cutting the center of the phenolic resin foam laminated plate in the thickness direction parallel to the front and back surfaces was taken, and a 9 cm avoiding voids was taken on the obtained photograph. Draw four straight lines of the length (corresponding to 1,800 μm in the actual foam cross section), calculate the number of cells measured according to the number of bubbles crossed by each straight line, and use the average value of them. The value obtained by dividing 1800 μm was taken as the average bubble diameter.

(7) A phenol resin foam laminated board having a color difference of 10 cm square was used as a sample, and a sample 1 having a thickness of 2 cm was cut out from the central portion in the thickness direction to obtain a sample 1 having a thickness of 10 cm × 10 cm × 2 cm. The average value X (L1 *, A1 *, B1 *) of the color values of the two cut surfaces (10 cm × 10 cm) cut out at this time was measured using a color difference meter (CR-410, manufactured by Konica Minolta). did. Next, Sample 1 was placed in an oven heated to 100 ° C. for 24 hours. Then, the sample 1 was taken out from the oven and further cut at the center in the thickness direction to obtain the sample 2 and the sample 3. The average value Y (L2 *, A2 *, B2 *) of the color values of each cut surface (10 cm × 10 cm, one surface each from sample 2 and sample 3) cut at this time is used as the above-mentioned color difference meter. Measured using. Then, from the color values X and Y, the color difference ΔE = {(L2 * -L1 *) ² + (A2 * -A1 *) ² + (B2 * -B1 *) ² } ^1/2 was calculated.

Claims (3)

It is a phenol resin foam laminated board in which face materials are arranged on at least the upper and lower surfaces of the phenol resin foam, and the phenol resin foam has a density of 10 kg / m ³ or more and 70 kg / m ³ or less and a closed cell ratio of 80. % Or more, and the color value X (L1 *, A1 *, B1 *) of the cut surface of the phenolic resin foam and the color value Y (L2) of the cut surface of the phenolic resin foam cut after heating at 100 ° C. for 24 hours. *, A2 *, B2 *) and color difference ΔE = {(L2 * -L1 *) ² + (A2 * -A1 *) ² + (B2 * -B1 *) ² } ^1/2 is 20.0 or less A phenolic resin foam laminated board characterized by being present. The phenol resin foam laminate according to claim 1, wherein the phenol resin foam contains at least one selected from the group consisting of chlorinated hydrofluoroolefins and non-chlorinated hydrofluoroolefins. A method for producing a phenol resin foam laminated board, wherein the oxygen concentration in each of the following steps (I) to (III) is 5% by volume or less.
(I) Synthesis step of synthesizing phenol resin using phenols and formaldehydes (II) Effervescence in the kneading step from the time when the pH of the phenol resin produced by the synthesis step is neutralized to 7.5 or less. Neutralization retention step of storing the phenol resin until the time when all the raw materials constituting the phenol resin composition are added (III) The lower surface of the effervescent phenol resin composition is distributed and widened by a plurality of discharge nozzles. Pre-foaming process of discharging onto the material and covering with the top material