JPH10139862A - Production of epoxy resin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for epoxy resin foam production which can give a flame retardant, high stiffness and dense epoxy resin foam by foaming and curing at a room temperature. SOLUTION: In this epoxy resin foam production process, a mixture of the following components A-F in the following proportion is foam-cured: A: 100 pts.wt. of an epoxy resin bearing 2 or more epoxy groups in the molecule; B: 5-200 pts.wt. of an aldehyde condensation resin; C: 10-300 pts.wt. of a flame retardant, at least one selected from metal hydroxide and metal oxide hydrate; D: 1-50 pts.wt. of a foaming agent; E: 0.01-10 pts.wt. of a foam stabilizer; F: at least one of phosphoric acid selected from ortho-phosphoric acid, polyphosphoric acid and phenylphosphonic acid in such an amount that the ratio of the number of hydroxyl groups in phosphoric acid to the number of epoxy groups in the epoxy resin becomes 0.4-1.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing an epoxy resin foam, and more particularly, to a method for producing a highly rigid and dense epoxy resin foam having flame retardancy at room temperature. The present invention relates to a method for producing an epoxy resin-based foam obtainable by foaming and curing.

[0002]

2. Description of the Related Art Conventionally, various resin foams have been used as heat insulating materials or lightweight members. Among them, polyurethane resin foams, phenol resin foams, and urea resin foams are widely used as thermosetting foams. However, in order to improve the heat resistance and mechanical properties of these resin foams, those obtained by adding a flame retardant to these resin foams are known.

[0003] In particular, phenolic resins are highly flame-retardant among thermosetting resins, and examples of phenolic resin foams obtained by adding an inorganic compound to them to improve mechanical properties, flame retardancy, and the like are given as examples. Many are known.

For example, Japanese Unexamined Patent Publication (Kokai) No. 61-176638 discloses that a resol type phenol resin having a methylol index of 0.7 or less, boric acid, aluminum hydroxide and / or magnesium hydroxide, an acidic curing agent and a foaming agent are mixed. A method for producing a quasi-incombustible organic foam material by foaming and curing this mixture has been disclosed, and a method for producing a phenol resin foam similar thereto has been disclosed in JP-A-61-268733.
JP-A-61-275335 and JP-A-62-89
It is also disclosed in JP-A-740.

Japanese Patent Application Laid-Open No. 63-137936 discloses that a high-concentration slurry containing a liquid acid-curable thermosetting resin, a liquid additive such as a foaming agent and a curing agent, and a liquid resin is used. There is disclosed a method for producing a foam in which a solid additive such as an inorganic powder is mixed and foam-cured.

[0006] Japanese Patent Application Laid-Open No. 2-182415 discloses that
Resol phenolic resin, surfactant, average particle size is 5
Disclosed is a non-combustible resin foamed building material containing aluminum hydroxide, a foaming agent, a curing agent, and the like containing at least a part of 0 μm or more.

Further, Japanese Patent Application Laid-Open No. 6-80814 discloses that
An acid-curable phenolic resin, by heating and foaming and curing a composition mixture containing aluminum hydroxide, a foam stabilizer, a foaming agent and a curing agent as essential components, whose pH has been previously adjusted to 6.5 to 7.4 with a weakly acidic substance. A method for producing a phenolic resin foam is disclosed.

On the other hand, epoxy resins which are excellent in adhesiveness to other materials, heat resistance, chemical resistance, dimensional stability and mechanical strength are also improved in mechanical properties and flame retardancy by adding inorganic compounds. Several examples of enhanced epoxy resin foams are known.

For example, JP-A-64-11138 discloses a method for producing a resin foam by mixing a synthetic resin such as an epoxy resin, a curing agent, and an inorganic oxide and / or an inorganic hydroxide. I have.

[0010] Also, JP-A-1-197553 discloses that
It is disclosed that an epoxy resin foam can be obtained at room temperature by using a composition comprising an epoxy resin, an amine-based curing agent, a curing accelerator, and an inorganic filler.

Japanese Patent Application Laid-Open No. 4-178440 discloses that
An epoxy resin composition for a flame-retardant lightweight composite material containing an epoxy resin, micro hollow spheres, a foaming agent, a flame retardant, a curing agent, and a curing accelerator is disclosed.

Further, JP-A-4-266940 discloses an epoxy resin composition for a composite material containing an epoxy resin, fine hollow spheres, a foaming agent, a flame retardant and an aromatic diamine.

As described above, various types of resin foams are widely used as heat insulating materials and lightweight members. Among them, building materials represented by heat insulating materials, core materials of sandwich panels and outer wall panels, etc. When it is used as, it is desired that the building material has flame retardancy and fire resistance. Therefore, various resin foams for these applications are preferably flame retardant or have fire resistance.

[0014]

However, although phenolic resin foams are flame-retardant, they have high friability,
Lack of adhesion to other materials such as steel plate and wood may cause a problem of peeling after construction.

The resol-type phenol resin uses an organic acid such as p-toluenesulfonic acid as a curing catalyst, but since the organic acid remains in the foam, it causes corrosion of the contacting metal and discoloration of the wood. And therefore,
As shown in the prior art (for example, see Japanese Patent Application Laid-Open No. 58-120644), the remaining organic acid is reacted with an epoxy resin and collected to modify the foam to remain. It is necessary to prevent the influence of the organic acid on other materials.

Further, since the resole type phenol resin releases formaldehyde during the foaming and curing process, there is a case where there is a problem that the working environment is impaired by the odor.

On the other hand, epoxy resin foams utilizing the properties of the resin itself as described above are used as jointing agents, lightweight members for automobiles and the like, building materials, and the like. The resin foam used for building materials such as the core material of the outer wall panel is desired to be flame retardant or have fire resistance. If a flame retardant or an inorganic filler is added to increase the flame retardancy, a resin foam having no disadvantages of the phenol resin foam may be provided.

However, fiber reinforced plastics (F
Unlike the case where a flame retardant or inorganic filler is added to a molded article such as RP), in the case of a resin foam, a large amount is added, although it depends on the quality and particle size of the flame retardant or inorganic filler to be added. In such a case, the flowability of the resin during foaming is reduced and the moldability into a predetermined shape is deteriorated, or the size and distribution of bubbles after foaming become uneven and the mechanical strength of the foam is reduced. Or the thermal conductivity increases and the heat insulation decreases,
There was a problem that the amount of addition was restricted, resulting in insufficient flame retardancy.

Specifically, the amount of the flame retardant or the inorganic filler is generally in the range of 20 to 40 parts by weight with respect to 100 parts by weight of the epoxy resin, and the upper limit is about equal parts by weight with respect to the epoxy resin. As a result, there is a problem that the flame retardancy and the fire resistance become insufficient.

The present invention solves the above-mentioned drawbacks of the prior art, and makes it possible to obtain a highly rigid and dense epoxy resin foam having flame retardancy by foam hardening at room temperature. The object of the present invention is to provide a method for producing a suitable epoxy resin foam.

[0021]

Means for Solving the Problems In order to achieve the above object, the construction of the method for producing an epoxy resin foam employed by the present invention comprises the following components A to D and F or F 'in the following amounts. The mixture is foamed and hardened at a specific ratio. A: epoxy resin having two or more epoxy groups in the molecule: 100 parts by weight B: aldehyde-based condensable resin: 5 to 200 parts by weight C: selected from metal hydroxides and metal oxide hydrates At least one flame retardant: 10 to 300 parts by weight D: foaming agent: 1 to 50 parts by weight E: foam stabilizer: 0.01 to 10 parts by weight F: phosphoric acid, polyphosphoric acid and phenyl At least one phosphoric acid selected from phosphonic acids: an amount such that the ratio of the number of hydroxyl groups of the phosphoric acids to the number of epoxy groups of the epoxy resin is 0.4 to 1.0, or F ′: phosphoric acid , At least one phosphoric acid selected from polyphosphoric acid and phenylphosphonic acid, and at least one phosphoric acid compound selected from phosphate and phosphate having a hydroxyl group bonded to a phosphorus atom. Quantity ratio of the object.. The number of epoxy groups of the epoxy resin the total number of hydroxyl groups of phosphoric acids and phosphate compounds in said mixture is 0.4 to 1.0

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to specific examples.

The epoxy resin in the present invention is a compound having two or more epoxy groups in a molecule, and is a compound which can be cured by reacting with a curing agent for an epoxy resin. It is a compound also called a main agent or a polyepoxide.

As the epoxy resin, a compound having a glycidyl group as an epoxy group is preferred, and a glycidyl ether epoxy resin is particularly preferred, but is not limited thereto. For example, a cycloaliphatic epoxy resin, glycidyl ester Epoxy resin, heterocyclic aliphatic epoxy resin, etc. (These epoxy resins are oligomer-based
May be used), or
One of these epoxy resins may be selected, or two or more thereof may be used in combination.

The epoxy resin is preferably a liquid at ordinary temperature in view of the ease of mixing with a flame retardant and the fluidity during foaming. Examples of such an epoxy resin include bisphenol A diglycidyl. Glycidyl ether epoxy resins such as ether, bisphenol F diglycidyl ether, resorcin diglycidyl ether, phenol novolak polyglycidyl ether, cresol novolak polyglycidyl ether; glycidyl ester epoxy resins such as hexahydrophthalic acid glycidyl ester and dimer acid glycidyl ester Linear aliphatic epoxy resins and cycloaliphatic epoxy resins.

The aldehyde-based condensable resin in the present invention is a compound which crosslinks and cures by condensing a methylol group in the molecule by heating or the like. For example, a resol type phenol having one or more methylol groups in the molecule Resins or amino resins can be mentioned.

The resole type phenol resin includes:
For example, a compound in which formaldehyde is added by 1 to 3 moles to 1 mole of a phenol such as phenol, cresol, xylenol, and resorcinol can be exemplified. In addition, a resin in which the number of nuclei is increased by precondensing a resol-type phenol resin can be used without any problem if it is in the B-stage state.

Examples of the amino resin include urea, melamine, benzoguanamine, acetoguanamine,
Compounds obtained by adding 1 to 3 mol of formaldehyde to 1 mol of glycouril, spirologamine and the like can be mentioned.

However, even if the amino resin is a compound in which formaldehyde is added to urea or the like and then the methylol group is etherified, for example, a compound such as hexamethoxymethylated melamine, etc. The curing reaction may not easily proceed with the heat of reaction due to the reaction with acids, and methanol generated from hexamethoxymethylated melamine or the like in the course of the curing reaction may adversely affect the foaming state of the foam, It is preferable to avoid using an amino resin having a methylol group etherified.

The liquid aldehyde-based condensable resin contains an organic solvent or water as a solvent.
When this solvent has an adverse effect on the foaming state of the foam,
Since water may hinder the reaction of the epoxy resin, it is preferable to use a solid or powdered aldehyde-based condensable resin containing no organic solvent or water.

In the present invention, the aldehyde-based condensable resin is used in an amount of 5 to 200 parts by weight per 100 parts by weight of the epoxy resin.
Although it is used in the range of parts by weight, in order to prevent water generated in the course of the condensation curing reaction of the aldehyde-based condensable resin from adversely affecting the foaming state of the foam, 30 parts by weight is required.
More preferably, it is used in the range of 100 parts by weight.

When the amount of the aldehyde-based condensable resin is 5
When the amount is less than 10 parts by weight, the effect of improving the flame retardancy of the foam by adding the aldehyde-based condensable resin is insufficient. The effect of improving the properties is not so large relative to the added amount, and rather, the fluidity of the epoxy resin or the like at the time of foaming may be reduced, and a foam having a desired size may not be obtained.

Examples of the flame retardant in the present invention include metal hydroxides such as aluminum hydroxide, calcium hydroxide, zirconium hydroxide, cerium hydroxide, and magnesium hydroxide, and calcium aluminate, montmorillonite and heidi. Light, hectorite, saponite,
Talc, pyrophyllite, vermiculite, mica, at least one selected from metal oxide hydrates including clay minerals such as dawsonite,
Among these, it is preferable to use aluminum hydroxide because of its large endothermic effect. Further, the flame retardant may be subjected to a surface treatment with stearic acid, a silane coupling agent or the like in order to improve the dispersibility in the epoxy resin.

In the present invention, the flame retardant is used in the range of 10 to 300 parts by weight with respect to 100 parts by weight of the epoxy resin. The moldability, flame retardancy, fire resistance and mechanical properties of the obtained foam are obtained. 30 from the viewpoint of balance of target strength
More preferably, it is used in the range of 250 parts by weight.

If the amount of the flame retardant is less than 10 parts by weight, the flame retardancy and fire resistance of the foam cannot be improved. Not only cannot the foam of a predetermined shape be obtained due to a decrease in the fluidity of the mixture at the time, but also the density of the foam increases, the weight increases, and the heat insulation performance decreases due to the destruction of the cells of the foam. It causes embrittlement.

Further, the flame retardant has an average particle diameter of 1 to 3.
The thickness is preferably 5 μm from the viewpoint of easy kneading to the resin and uniform dispersion in the foam.
More preferably, it is 100 μm.

If the average particle size of the flame retardant is less than 1 μm, the bulk may be increased and the handling properties and the kneading to the resin may be poor. If the average particle size exceeds 300 μm, The bulk specific gravity increases, and depending on the specific gravity difference with the resin or the like, sedimentation is likely to occur, and it may be difficult to uniformly disperse the foam in the foam (the above-mentioned average particle diameter in the present invention refers to a sedimentation balance method). Alternatively, it means the value of D50 measured by dry sieve analysis (50% value of the cumulative distribution).

Examples of the foaming agent in the present invention include known ones such as halogenated hydrocarbons and hydrocarbons. Among them, halogenated hydrocarbons having a boiling point of 0 to 100 ° C. are preferable. In particular, halogenated hydrocarbons that are liquid at room temperature are preferred. These foaming agents can be used alone or as a mixture of two or more.

Examples of the halogenated hydrocarbons include chlorinated hydrocarbons such as methylene chloride and trichloroethylene; 2,2-dichloro-1,1,1-trifluoroethane (HCFC123); -1-fluoroethane (HCFC141b), 1,1-dichloro-2,2,3,3,3-pentafluoropropane (HC
FC225ca), 1,3-dichloro-1,1,2,2
2,3-pentanefluoropropane (HCFC225c
b) chlorinated fluorinated hydrocarbons such as 1,1,1,2,2
3,3-hexafluoropropane (HFC236e
a) and fluorinated hydrocarbons such as 1,1,1,3,3-pentafluoropropane (HFC245fa).

In the present invention, the foaming agent is used in an amount of 1 to 50 parts by weight with respect to 100 parts by weight of the epoxy resin. If it exceeds, the number of open cells increases, the closed cell rate decreases, and the rigidity and heat insulation of the foam decrease.

Further, since the expansion ratio and density of the foam are changed by increasing or decreasing the amount of the foaming agent used, the amount of the foaming agent is adjusted so that the foam density required according to the use of the foam is obtained. Adjustment is preferred.

Examples of the foam stabilizer in the present invention include known ones used in the production of various resin foams such as polyurethane resin foam and phenol resin foam.

As the foam stabilizer, a surfactant is preferred, and more preferably, the surfactant is a nonionic surfactant. These foam stabilizers may be used alone or in combination of two or more.

Examples of the nonionic surfactant which can be used as the foam stabilizer as described above include sorbitan esters such as sorbitan monostearate, sorbitan monooleate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monooleate. Polyethylene glycol esters such as polyethylene glycol monostearate, polyethylene glycol monosoleate, polyethylene glycol distearate, and polyethylene glycol dioleate; polyoxyethylene alkyl ethers other than those described above; polyoxyethylene alkyl esters; polyoxyethylene Alkylphenyl ethers; polyoxyethylene alkylphenyl esters, dimethylpolysiloxane polyoxyalkylene copolymers, etc. It can gel.

In the present invention, the foam stabilizer is used in an amount of 0.01 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the epoxy resin. If the amount is less than 01 parts by weight, the effect of uniformizing the size and distribution of the bubbles after foaming is lacking. If the amount is more than 10 parts by weight, it acts as a plasticizer and lowers the rigidity of the foam.

The phosphoric acid in the present invention comprises at least one selected from phosphoric acid, polyphosphoric acid and phenylphosphonic acid. The phosphoric acid reacts with the epoxy resin to form a skeleton of a resin foam. At the same time
It is also a component that imparts flame retardancy to the resin foam.

Among the above phosphoric acids, phosphoric acid is not particularly limited.
%, 85%, or 89%.

As for polyphosphoric acid, various grades of polyphosphoric acid are commercially available depending on the content of P ₂ O ₅ .
It can be used without particular limitation, and there is no limitation on phenylphosphonic acid.

As the phosphoric acids, at least one of phosphoric acid, polyphosphoric acid and phenylphosphonic acid may be used, but two or more of them may be used. still,
Since phenylphosphonic acid among the above is a solid, it is preferable to use it in combination with phosphoric acid or polyphosphoric acid, which is a liquid, in order to easily flow during foaming and curing.

It is considered that the above-mentioned phosphoric acid reacts with the epoxy group of the epoxy resin and is taken into the molecular skeleton of the epoxy resin. Therefore, the phosphoric acid is obtained by controlling the amount of the phosphoric acid to an appropriate amount. Phosphoric acids can be prevented from remaining as free acids in the resulting foam. Therefore, by controlling in such a manner, even when the resin foam of the present invention is bonded to other materials such as metal and wood, for example, a neutralizing agent for preventing corrosion to metal and discoloration to wood is required. do not do.

On the other hand, since phosphoric acid reacts rapidly with the epoxy group of the epoxy resin, as described later, both can react by simply mixing to form a foam. However, in some cases, the calorific value due to a rapid reaction with an epoxy group becomes too large, and foaming (vaporization) occurs at once depending on the type of a foaming agent, so that a dense foam may not be formed. In such a case, at least one type of phosphoric acid selected from a phosphate having a hydroxyl group bonded to a phosphorus atom and a phosphoric acid ester is used together with the phosphoric acid in order to control the reaction and suppress the heat generation. It is preferable to use a compound (hereinafter, sometimes simply referred to as a phosphoric acid compound) in combination.

In the present invention, by using the above phosphoric acid compound in combination, the reaction with the epoxy group is controlled so that the calorific value is suppressed, and a good foam can be produced. Since it is also a component that imparts flame retardancy to the resin foam, even if it is used in a relatively large amount with respect to the phosphoric acids, there is little risk of lowering the flame retardancy of the obtained resin foam.

In the above phosphoric acid compound, at least one hydroxyl group bonded to a phosphorus atom is required to react with the epoxy group of the epoxy resin. At least one of them may be used, but two or more of them may be used.

Examples of the phosphate include ammonium dihydrogen phosphate, diammonium hydrogen phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, and phosphoric acid. Examples thereof include calcium dihydrogen, calcium monohydrogen phosphate, aluminum dihydrogen phosphate, and dialuminum hydrogen phosphate. Examples of the phosphate include monomethyl phosphate, dimethyl phosphate, monoethyl phosphate, diethyl phosphate, propyl phosphate, isopropyl phosphate, and butyl phosphate.
, Lauryl phosphate, stearyl phosphate,
Examples thereof include 2-ethylhexyl phosphate and isodecyl phosphate.

Further, since the above-mentioned phosphoric acids also function as a curing catalyst for the aldehyde-based condensable resin, there is no need to heat the aldehyde-based condensable resin for curing.

In the present invention, the phosphoric acid is used in such an amount that the ratio of the number of hydroxyl groups of the phosphoric acid to the number of epoxy groups of the epoxy resin is 0.4 to 1.0. When the amount used is less than 0.4 in the above ratio, the heat of reaction generated by the reaction with the epoxy resin is small, the foaming (vaporization) of the foaming agent becomes insufficient, and the foam having a desired foaming ratio is obtained. Is difficult to obtain. When the amount of the phosphoric acid exceeds 1.0 in the above ratio, the phosphoric acid often becomes excessive, and the ratio of remaining as a free acid in the foam increases. In this case, The foamed state of the foam deteriorates, and when the foam comes into contact with metal or wood, the risk of corrosion or discoloration of the foam increases.

The amount of phosphoric acid used depends on the purpose of the foam,
It is preferable to adjust to a more appropriate amount depending on the production method and production conditions, etc., and from the workability during foaming, the uniformity of the mechanical strength and heat insulation of the foam, the above ratio is 0.4 to 0.8. It is more preferable to use an amount that results in

When the above phosphoric acid compound is used in combination,
The total amount of the phosphoric acid and the phosphoric acid compound is such that the ratio of the total number of hydroxyl groups of the phosphoric acid and the phosphoric acid compound to the number of epoxy groups of the epoxy resin is 0.4 to 1.0.

The amount of the phosphoric acid compound to be used with respect to the phosphoric acid can be selected in accordance with the use of the foam, the production method, the production conditions, and the like in the same manner as described above. It can be adjusted appropriately so as to obtain the curing time.

Although not particularly limited, the ratio of phosphoric acid to the total of phosphoric acid and phosphoric acid compound is 40%.
If the amount of phosphoric acid is too small, the reactivity with the epoxy resin may be insufficient. When a solid phosphoric acid compound is used, it is preferable to use it in combination with a liquid phosphoric acid, polyphosphoric acid, or the like in order to easily flow during foaming and curing.

In the present invention, the ratio of the number of hydroxyl groups of the phosphoric acid to the number of epoxy groups of the epoxy resin means a value obtained by dividing the number of hydroxyl groups of the phosphoric acid by the number of epoxy groups of the epoxy resin. The number of epoxy groups in the epoxy resin is the value obtained by dividing the amount of the epoxy resin used by the epoxy equivalent of the epoxy resin, and when two or more epoxy resins are used, the use of each epoxy resin It means the total value of the values obtained by dividing the amount by the epoxy equivalent of each epoxy resin, and the number of hydroxyl groups of the phosphoric acid is the value obtained by dividing the amount of the phosphoric acid used by the hydroxyl equivalent of the phosphoric acid. When two or more types of phosphoric acids are used, the total value of the values obtained by dividing the amount of each phosphoric acid used by the hydroxyl equivalent of each phosphoric acid is used, and the phosphoric acid and the phosphoric acid compound are used in combination. If it is also the same.

Here, the epoxy equivalent is a value obtained by dividing the average molecular weight of the epoxy resin by the number of epoxy groups per molecule, and the hydroxyl equivalent is the formula weight of phosphoric acid or phosphoric acid compound bonded to phosphorus atom. This is a value obtained by dividing by the number of hydroxyl groups obtained.

In the method for producing an epoxy resin foam of the present invention, in addition to the above-mentioned flame retardants, fillers and pigments are used for the purpose of adjusting the fluidity and the like at the time of foaming hardening and economical effects. These may be used by mixing them with an epoxy resin or the like according to a standard method.

Since a mixture containing an epoxy resin and phosphoric acid or the like usually reacts at normal temperature, in the method for producing an epoxy resin foam of the present invention, the epoxy resin is mixed with a phosphoric acid or a phosphoric acid and a phosphoric acid compound. It is preferable to mix the mixture (hereinafter sometimes simply referred to as phosphoric acid or the like) at room temperature to form a reactive mixture. However, when the epoxy resin is a liquid having a high viscosity, the epoxy resin and the phosphoric acid And the like can be performed under heating.

The above-mentioned aldehyde-based condensable resin, flame retardant,
The foaming agent and the foam stabilizer can be mixed with these at the same time when they are mixed, but at least one of the two is mixed with an aldehyde-based condensable resin, a flame retardant, a foaming agent or a foam stabilizer in advance. When pre-mixed, it is mixed with an epoxy resin-containing component to form a pre-mixture because of the ease of mixing, and the pre-mixture is mixed with a component containing phosphoric acid and the like to react. It is preferable to use a mixture of the same.

In particular, since the flame retardant is a powder, it is preferable to mix it with a component containing an epoxy resin in advance in order to improve the fluidity of the mixture during foaming and dispersion in the foam. These mixing can be performed using a kneader, a mixing roll, a Henschel mixer or the like.

Epoxy resin, aldehyde-based condensable resin,
A reactive mixture containing a flame retardant, a foaming agent, a foam stabilizer, phosphoric acid, and the like can start the reaction at room temperature, and the reaction proceeds while generating heat, and foams due to the vaporization of the foaming agent. It cures to form an epoxy resin foam, and as a device for mixing and discharging and injecting such a component, a multi-component mixer generally used in the production of polyurethane resin foam and the like is used. It is preferred to use a mixing device referred to as

As a method of molding the epoxy resin foam obtained by the present invention into a desired shape, a method of injection foaming in which the raw material components are injected into a mold of a desired size and shape while mixing and foaming and curing are performed. Or a slab foaming method or the like in which the raw material components are mixed and flowed on a flat surface, and before the mixture is cured, the surface of the mixture during foaming and curing is scraped to a predetermined thickness by a doctor blade or the like, and the mixture is cured. Can be.

The epoxy resin foam obtained according to the present invention can be used for the same applications as conventional resin foams. For example, the foam obtained by the slab foaming method is cut out into a desired shape by cutting out a foamed body, and it can be used for applications such as a plate-shaped heat insulating material used for a building such as a house such as a housing such as an underfloor heat insulating material. Also, it can be used for a heat insulating material by foaming between an inner wall and an outer wall of a building such as a refrigerated warehouse by an injection foaming method. It can also be used as a core material for doors and sandwich panels. Furthermore, a composite material such as synthetic wood can be obtained by impregnating a mixture of the above-mentioned raw materials with a reinforcing fiber such as a glass fiber and foaming and hardening the mixture.

[0070]

The mixture of the epoxy resin and phosphoric acid reacts rapidly at room temperature to generate heat. By utilizing the heat of reaction for vaporizing the foaming agent, the mixture of the epoxy resin and phosphoric acid can be used. The mixture can be easily and quickly cured at room temperature without heating to obtain an epoxy resin foam.

Further, since phosphoric acids and the like react and are taken into the resin skeleton constituting the epoxy resin foam,
Phosphoric acid and the like function in the same manner as the reactive flame retardant, and an epoxy resin foam having high flame retardancy can be obtained.

Further, by combining an aldehyde-based condensable resin having low flammability among organic materials and an epoxy resin, the flame retardancy of the foam can be further enhanced.

The metal hydroxide or metal oxide hydrate added as a flame retardant not only enhances the flame retardancy of the foam, but also functions as an inorganic filler to provide dimensional stability and heat resistance of the foam. Deformability is also improved.

Further, since a part of the flame retardant reacts with phosphoric acid or the like and is taken into the resin skeleton constituting the epoxy resin foam, the flame retardant remaining without being taken in with the resin containing the flame retardant And a greater amount of flame retardant can be uniformly dispersed in the foam without destroying the cells as compared with conventional resin foams. When the sandwich panel is exposed to a flame, for example, when the temperature of the foam reaches 200 to 500 ° C., dehydration or crystallization water is removed. Since the heat is absorbed by releasing the heat, the temperature rise of the panel and the heat transfer to the opposite surface can be suppressed.

Further, phosphoric acids and the like incorporated in the resin skeleton constituting the epoxy resin foam act as a dehydration and carbonization accelerator when exposed to the above-mentioned high temperature, and the It promotes the release of water and forms a heat insulating layer of carbonized cells, so that the shape and heat insulating properties of the foam are maintained even after exposure to high temperatures.

[0076]

The present invention will be described in more detail with reference to the following examples.

Example 1 As an aldehyde condensable resin, 2.2 mol of formaldehyde was added to 100 mol of a phenol novolak polyglycidyl ether epoxy resin having an epoxy equivalent of 175 g / eq and a molecular weight of about 600 per mol of melamine. 50 parts by weight of a powdery amino resin, 1 part by weight of a dimethylpolysiloxane polyoxyalkylene copolymer as a foam stabilizer, and 100 parts by weight of aluminum hydroxide having an average particle diameter of 30 μm as a flame retardant are kneaded in a three-roll mill. Kneading using a mixer, and further, 1,1-dichloro- as a foaming agent.
The X-component obtained by adding 10 parts by weight of 1-fluoroethane was put in a raw material tank of a multi-component mixed foaming machine. next,
85% phosphoric acid for industrial use was used as the Y component and placed in another raw material tank. The X and Y components were fed into the mixing head at a discharge weight ratio of X: Y = 100: 6.7 at a total flow rate of 3 kg / min to discharge the mixture. This corresponds to 0.8 in the ratio of the number of hydroxyl groups of phosphoric acid to the number of epoxy groups of the epoxy resin. When 3750 g of this mixture was immediately placed in a 500 × 500 × 100 mm room-temperature metal frame, foaming started 20 seconds after injection, and foam hardening was completed 2 minutes later.

Example 2 A powdery aldehyde condensable resin was prepared by adding 2.5 mol of formaldehyde to 1 mol of phenol to 100 parts by weight of a bisphenol A diglycidyl ether epoxy resin having an epoxy equivalent of 180 g / eq. Using a three-roll kneader, 20 parts by weight of a resol type phenol resin, 2 parts by weight of polyoxyethylene sorbitan monostearate as a foam stabilizer, and 120 parts by weight of magnesium hydroxide having an average particle diameter of 30 μm as a flame retardant were used. Kneaded, and 1,1-dichloro-2,2,
What added the 3,3,3-pentafluoropropane 20 weight part was made into the X component, and was put into the raw material tank of the multi-component mixing foaming machine. Next, a mixture of industrial 89% phosphoric acid and phenylphosphonic acid at a molar ratio of 1: 1 and a weight ratio of 0.7: 1 was used as a Y component, and was placed in another raw material tank. X, Y
At a discharge weight ratio of X: Y = 100: 11.2.
The mixture was fed into the mixing head at a total flow rate of 3 kg / min to discharge the mixture. This corresponds to a ratio of the number of hydroxyl groups of phosphoric acid and phenylphosphonic acid to the number of epoxy groups of the epoxy resin of 1.0. This mixture 3
When 750 g was immediately placed in a 500 × 500 × 100 mm room temperature metal frame, foaming started 1 minute after injection,
After 5 minutes the foam hardening was complete.

Example 3 Urea 1 was added to 100 parts by weight of a bisphenol A diglycidyl ether epoxy resin having an epoxy equivalent of 180 g / eq.
70 parts by weight of a powdery amino resin as an aldehyde-based condensable resin, 2 parts by weight of formaldehyde, 3 parts by weight of polyoxyethylene sorbitan monostearate as a foam stabilizer, and an average as a flame retardant 80 parts by weight of montmorillonite having a particle diameter of 60 μm is kneaded using a three-roll kneader, and 1,1-
What added 20 parts by weight of dichloro-1-fluoroethane was designated as X component, and the mixture was placed in a raw material tank of a multi-component mixed foaming machine. Next, a mixture of 76% of polyphosphoric acid in terms of P ₂ O ₅ and aluminum dihydrogen phosphate hexahydrate in a molar ratio of 2: 1, and a weight ratio of 1: 1.14 was used as another Y component. Put in the raw material tank. X: Y = 100: 1
With a discharge weight ratio of 3.5, a total of 3 kg for the mixing head
/ Min, and the mixture was discharged. This corresponds to a ratio of the number of hydroxyl groups of polyphosphoric acid and aluminum dihydrogen phosphate hexahydrate to the number of epoxy groups of the epoxy resin of 0.7. Immediately after placing 3750 g of this mixture in a 500 × 500 × 100 mm room temperature metal frame, foaming started 1 minute and 20 seconds after the injection, and foam hardening was completed 5 minutes later.

Comparative Example 1 As an aldehyde condensable resin, 2.2 mol of formaldehyde was added to 100 mol of a phenol novolak polyglycidyl ether epoxy resin having an epoxy equivalent of 175 g / eq and a molecular weight of about 600 to 1 mol of melamine. 20 parts by weight of a powdery amino resin, 2 parts by weight of polyoxyethylene sorbitan monostearate as a foam stabilizer, and 100 parts by weight of aluminum hydroxide having an average particle diameter of 30 μm as a flame retardant were subjected to a three-roll kneader. And kneading the mixture, and further using 1,1-dichloro-2,
What added 20 parts by weight of 2,3,3,3-pentafluoropropane was designated as X component, and was put in a raw material tank of a multi-component mixed foaming machine. Next, a mixture of industrial 89% phosphoric acid and phenylphosphonic acid at a molar ratio of 1: 1 and a weight ratio of 0.7: 1 was placed in another raw material tank as a Y component.
The X and Y components were fed into the mixing head at a discharge weight ratio of X: Y = 100: 7.2 at a total flow rate of 3 kg / min to discharge the mixture. This corresponds to 1.5 in the ratio of the number of hydroxyl groups of phosphoric acid and phenylphosphonic acid to the number of epoxy groups of the epoxy resin. When 3750 g of this mixture was immediately placed in a 500 × 500 × 100 mm room-temperature metal frame, foaming started 30 seconds after injection, and foaming hardening was completed 2 minutes and 30 seconds later. However, the obtained foam had a non-uniform cell size and distribution, and had large cavities inside.

Comparative Example 2 A powdery aldehyde condensable resin was prepared by adding 2.2 mol of formaldehyde to 1 mol of melamine to 100 parts by weight of bisphenol A diglycidyl ether epoxy resin having an epoxy equivalent of 180 g / eq. 80 parts by weight of an amino resin, 1 part by weight of polyoxyethylene sorbitan monostearate as a foam stabilizer, and 350 parts by weight of aluminum hydroxide having an average particle diameter of 30 μm as a flame retardant were kneaded using a three-roll kneader. Further, a mixture obtained by adding 20 parts by weight of 1,1-dichloro-1-fluoroethane as a foaming agent was designated as an X component, and the mixture was placed in a raw material tank of a multi-component mixed foaming machine. Next, 85% phosphoric acid for industrial use was used as the Y component and placed in another raw material tank. X and Y are represented by X: Y
= 100: 3.1, and the mixture was fed into the mixing head at a total flow rate of 3 kg / min to discharge the mixture. This corresponds to 0.8 in the ratio of the number of hydroxyl groups of phosphoric acid to the number of epoxy groups of the epoxy resin. Immediately, 3750 g of this mixture is 500 × 500 × 100 m
When placed in a metal frame at room temperature of m, foaming started 2 minutes and 30 seconds after injection, and foam hardening was completed 8 minutes later. However, the obtained foam was insufficiently foamed and could not have a predetermined size.

Comparative Example 3 100 parts by weight of a powdery resol type phenol resin, 2 parts by weight of a dimethylpolysiloxane polyoxyalkylene copolymer as a foam stabilizer, and aluminum hydroxide having an average particle diameter of 30 μm as a flame retardant 100 parts by weight were kneaded using a three-roll kneader, and 1,1 as a foaming agent was further added.
The mixture obtained by adding 20 parts by weight of dichloro-1-fluoroethane was designated as X component, and the mixture was put in a raw material tank of a multi-component foaming machine. Next, a 60% aqueous solution of phenylphosphonic acid was used as the Y component and placed in another raw material tank. X and Y are represented by X:
At a discharge weight ratio of Y = 100: 15, the mixture was fed into the mixing head at a total flow rate of 3 kg / min to discharge the mixture. 3750 g of this mixture was immediately added to 500 × 500 × 1
When the mixture was poured into a 00 mm metal frame at room temperature and heated to 60 ° C., foaming started 3 minutes and 30 seconds after heating, and foam hardening was completed 10 minutes later.

The physical properties of the foams obtained by the above Examples and Comparative Examples are shown in Table 1 below.

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[Table 1]

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According to the method for producing an epoxy resin foam of the present invention, as shown in the above examples, foaming and curing easily and quickly at room temperature, high heat insulation, high rigidity and dense flame retardancy. Can be obtained.

In the epoxy resin foam obtained by the present invention, phosphoric acid and the like are incorporated in the resin skeleton constituting the foam, and the use of phosphoric acid and the like makes it possible to compare with the prior art. As a result, a larger amount of the flame retardant can be uniformly dispersed in the foam, so that the flame retardancy and the fire resistance are excellent.

Further, in the method for producing an epoxy resin foam of the present invention, a foam having high flame retardancy can be obtained by combining an epoxy resin and an aldehyde condensable resin.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 63/00 C08L 63/00 B

Claims (5)

[Claims] 1. A method for producing an epoxy resin foam, comprising foaming and curing a mixture containing the following components A to F in the following quantitative ratios. A: epoxy resin having two or more epoxy groups in the molecule: 100 parts by weight B: aldehyde-based condensable resin: 5 to 200 parts by weight C: selected from metal hydroxides and metal oxide hydrates At least one type of flame retardant: 10 to 300 parts by weight D: foaming agent: 1 to 50 parts by weight E: foam stabilizer: 0.01 to 10 parts by weight F: phosphoric acid, polyphosphoric acid and phenyl At least one phosphoric acid selected from phosphonic acids: an amount such that the ratio of the number of hydroxyl groups of the phosphoric acids to the number of epoxy groups of the epoxy resin is 0.4 to 1.0. 2. A method for producing an epoxy resin foam, comprising foaming and curing a mixture containing the following components A to F ′ in the following quantitative ratios. A: epoxy resin having two or more epoxy groups in the molecule: 100 parts by weight B: aldehyde-based condensable resin: 5 to 200 parts by weight C: selected from metal hydroxides and metal oxide hydrates At least one flame retardant: 10 to 300 parts by weight D: foaming agent: 1 to 50 parts by weight E: foam stabilizer: 0.01 to 10 parts by weight F ': phosphoric acid, polyphosphoric acid and A mixture of at least one phosphoric acid selected from phenylphosphonic acid, and at least one phosphoric acid compound selected from phosphate and phosphate having a hydroxyl group bonded to a phosphorus atom; phosphoric acids in the mixture; An amount such that the ratio of the total number of hydroxyl groups of the phosphoric acid compound to the number of epoxy groups of the epoxy resin is 0.4 to 1.0. 3. The epoxy resin according to claim 1, wherein the epoxy resin is at least one selected from a glycidyl ether epoxy resin, a glycidyl ester epoxy resin, a linear aliphatic epoxy resin and a cycloaliphatic epoxy resin.
3. The method for producing an epoxy resin-based foam according to item 1. 4. The method for producing an epoxy resin foam according to claim 1, wherein the aldehyde-based condensable resin is in a solid or powder form. 5. The method for producing an epoxy resin foam according to claim 1, wherein the flame retardant has an average particle size of 1 to 300 μm.