JPH1121366A - Production of epoxy resin-based foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process that can give a flame-retardant highly rigid dense epoxy resin foam by expansion and curing at ordinary temperature. SOLUTION: This process comprises foaming and curing a mixture containing 100 pts.wt. liquid reaction product obtained by reacting an epoxy resin having at least two epoxy groups in the molecule with an aldehydic condensible resin and having an epoxy equivalent of 2,000 g/eq or below, 10-300 pts.wt. at least one flame retardant selected among metal hydroxides and metal oxide hydrates, 1-5 pts.wt. blowing agent, 0.01-10 pts.wt. foam stabilizer and at least one phosphoric acid selected among phosphoric acid, polyphosphoric acid and phenylphosphonic acid and used in an amount to give a ratio of the number of the hydroxyl groups of the phosphoric acid to the number of the epoxy groups of the reaction product of 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 a high-concentration slurry of a liquid acid-curable thermosetting resin, a liquid additive such as a foaming agent and a curing agent, and a liquid resin. There is disclosed a method for producing a foam in which a solid additive such as an inorganic powder is mixed and foamed and 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, lightweight members, and the like. Among them, among others, architectural materials represented by heat insulating materials, core materials of sandwich panels and outer wall panels, and the like. When used as a material, since it is desired that the building material has flame retardancy and fire resistance, 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 adhesiveness with other materials such as steel plate and wood, peeling after construction may be a problem, and this is because water generated in the process of foaming and hardening of phenolic resin foam may damage the foam structure Therefore, it is necessary to take some measures to prevent the influence of this water.

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 disadvantages of the prior art, and provides a highly rigid and dense epoxy resin foam having flame retardancy by foam hardening at room temperature. It has been made to provide a possible method for producing an epoxy resin-based 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 E or E 'in the following amounts. The mixture is foamed and hardened at a specific ratio. A: obtained by reacting an epoxy resin having two or more epoxy groups in a molecule with an aldehyde-based condensable resin;
Liquid reaction product having an epoxy equivalent of 2000 g / eq or less: 100 parts by weight B: at least one flame retardant selected from metal hydroxides and metal oxide hydrates: 10 to 300 parts by weight C: foaming Agent: 1 to 50 parts by weight D: foam stabilizer: 0.01 to 10 parts by weight E: at least one phosphoric acid selected from phosphoric acid, polyphosphoric acid and phenylphosphonic acid An amount such that the ratio of the number of hydroxyl groups to the number of epoxy groups in the reaction product is 0.4 to 1.0, or E ′: at least one phosphoric acid selected from phosphoric acid, polyphosphoric acid and phenylphosphonic acid And a mixture of at least one phosphoric acid compound selected from a phosphate having a hydroxyl group bonded to a phosphorus atom and a phosphoric acid ester. Phosphoric acid and phosphoric acid compound in the mixture The amount of the ratio of the total number of hydroxyl groups, to the number of epoxy groups of the reaction product becomes 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, which is a compound which can be cured by reacting with a curing agent for epoxy resin. Or a compound also called polyepoxide or the like.

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, linear aliphatic epoxy resin, etc. (these epoxy resins may be oligomeric)
May be used, and 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 epoxy resin, bisphenol F diglycidyl ether epoxy resin, resorcin diglycidyl ether epoxy resin, phenol novolak polyglycidyl ether epoxy resin, cresol novolac polyglycidyl ether epoxy resin; Glycidyl ester type epoxy resins such as glycidyl phthalate type epoxy resin and glycidyl ester dimer type epoxy resin; 3,4-epoxy-6-methylcyclohexylmethyl carboxylate and 3,4-epoxy It can be exemplified shea cyclohexylmethyl carboxylate cycloaliphatic epoxy resins.

The aldehyde-based condensable resin in the present invention is a compound which crosslinks and cures when a methylol group in the molecule is condensed by heating or the like. For example, a resol having one or more methylol groups in the molecule is used. Phenolic resins or amino resins.

The resole type phenol resin includes:
For example, phenol, cresol, xylenol, 1 mole of phenols such as resorcinol, 1 to 3 moles of a compound obtained by adding formaldehyde can be mentioned,
Further, a resol type phenol resin obtained by precondensing the nucleus by precondensation can be used without any problem if it is in the B-stage state.

Examples of the amino resin include urea, melamine, benzoguanamine, acetoguanamine,
For 1 mol of glycouril, spiroganamin, etc.,
Compounds obtained by adding 1 to 3 mol of formaldehyde can be used.

The liquid aldehyde-based condensable resin contains an organic solvent or water as a solvent.
When obtaining a reaction product of an epoxy resin and an aldehyde-based condensable resin described below, since an organic solvent or water may inhibit the reaction between the two, a solid or powder containing no organic solvent or water may be used. It is preferable to use the aldehyde-based condensable resin of the above.

A liquid reaction product having an epoxy equivalent of 2000 g / eq or less (hereinafter simply referred to as epoxy resin) obtained by reacting an epoxy resin having two or more epoxy groups in a molecule with an aldehyde-based condensable resin. The reaction product (which may be referred to as a reaction product) needs to be capable of further reacting with a phosphoric acid described below, and therefore needs to have an epoxy group. Therefore, in the present invention, this epoxy resin reaction product The epoxy equivalent is 2000
Use a material having a g / eq or less.

The epoxy resin reaction product preferably has an epoxy equivalent of 500 to 1400 g / eq from the viewpoint of the reactivity between the epoxy resin reaction product and phosphoric acids described below.

The epoxy resin reaction product is preferably a liquid having a relatively low viscosity at room temperature in order to be mixed with phosphoric acid and foamed as described later, but is relatively low at room temperature. Even if it has a high viscosity, any liquid that has a relatively low viscosity under heating may be used.

The ratio of the epoxy resin and the aldehyde-based condensable resin to react with each other to obtain the above-mentioned epoxy resin reaction product is based on the ratio of the aldehyde-based condensable resin to 100 parts by weight of the epoxy resin. 100 parts by weight, when the ratio of the aldehyde-based condensable resin to 100 parts by weight of the epoxy resin is less than 1 part by weight,
When the flame retardancy of the obtained foam is inferior, the proportion of the aldehyde-based condensable resin is more than 100 parts by weight. There is a possibility that the epoxy group for reacting with an acid or the like decreases, and the epoxy equivalent does not become 2000 g / eq or less.

In addition, when the proportion of the aldehyde-based condensable resin exceeds 100 parts by weight, gelation or otherwise excessively increase the viscosity of the epoxy resin reaction product when forming a foam. Fluidity is reduced, moldability for molding into a predetermined shape is deteriorated, and a foam having desired dimensions and density may not be obtained.

That is, in view of the flame retardancy of the foam, the reactivity with phosphoric acids, etc., and the ease of controlling the viscosity of the epoxy resin reaction product, the more preferable ratio of both is 100 parts by weight of the epoxy resin. 10 to 100 parts by weight of the aldehyde-based condensable resin.

When a solid aldehyde-based condensable resin is used, the epoxy resin reaction product is heated and melted, then mixed with the epoxy resin, or a liquid aldehyde-based condensable resin is used. In this case, it can be obtained by a method in which the mixture is directly mixed with an epoxy resin and then heated to cause a reaction.

The reaction temperature in the above reaction is 80 to 200.
C. is preferable, and the reaction proceeds sufficiently if the reaction temperature is in this range, and the viscosity of the obtained epoxy resin reaction product does not rise so remarkably that a foam cannot be obtained. In consideration of the fluidity of the epoxy resin reaction product at the time of production, it is preferable to react at a relatively low temperature of 80 to 150 ° C. to obtain a lower viscosity epoxy resin reaction product.

Further, since the epoxy equivalent of the obtained epoxy resin reaction product varies depending on the ratio of the aldehyde-based condensable resin to the epoxy resin, the reaction temperature and the reaction time, the epoxy equivalent is set to 2000 g / eq or less. What is necessary is just to set those conditions suitably.

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 and silicate. Calcium, zinc silicate or at least one metal oxide hydrate selected from clay minerals such as montmorillonite, helilite, wollastonite, willemite, hectorite, saponite, talc, pyrophyllite, vermiculite, mica, dawsonite. Among these, aluminum hydroxide is preferably used because of its high endothermic effect.

In the present invention, the flame retardant is used in an amount of 10 to 300 parts by weight based on 100 parts by weight of the epoxy resin reaction product. From the viewpoint of the balance between properties and mechanical strength, it is more preferable to use 50 to 200 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. The fluidity of the mixture at the time decreases, not only is it impossible to obtain a foam of a predetermined shape, but also the density of the foam increases and the weight increases, and the flame retardancy and The fire resistance cannot be improved, and instead, the heat insulation performance is degraded due to the destruction of the cells of the foam, embrittlement, and poor adhesion to the skin material are caused.

Further, the flame retardant has an average particle diameter of 1 to 3.
The thickness is preferably 00 μm, and more preferably 5 to 100 μm from the viewpoint of easy kneading to the epoxy resin reaction product and uniform dispersion in the foam.

If the average particle size of the above-mentioned flame retardant is less than 1 μm, the bulk becomes high and the handleability and the kneading to the epoxy resin reaction product may be poor, or the flow during foaming may be poor. However, if the average particle diameter exceeds 300 μm, the formation of cells of the foam is hindered, the closed cell ratio decreases, the thermal conductivity increases, and the heat insulating property decreases. sometimes (and the average particle diameter in the present invention means the value of D ₅₀ measured by the sedimentation balance method or a 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 addition, hydrocarbons such as pentane and cyclohexane, and ethers such as petroleum ether and isopropyl ether can also be used as the foaming agent. It is not preferable to use a flammable foaming agent as described above.

In the present invention, the foaming agent is used in an amount of 1 to 50 parts by weight based on 100 parts by weight of the epoxy resin reaction product. If the amount is less than 1 part by weight, foaming becomes insufficient. If it exceeds 50 parts by weight, the number of open cells increases, the closed cell ratio decreases, and the rigidity and heat insulation of the foam decrease.

Further, by increasing or decreasing the amount of the foaming agent used,
Since the expansion ratio and density of the foam change, it is preferable to adjust the amount of the foaming agent so that the foam density required according to the use of the foam or the like is obtained.

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

Among the above foam stabilizers, surfactants are preferable, and more preferably, the surfactants are nonionic surfactants. These foam stabilizers can be used alone or in combination of two or more.

Examples of the nonionic surfactant which can be used as the above-mentioned foam stabilizer include sorbitan monostearate, sorbitan monooleate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate and the like. Sorbitan esters of the following; polyethylene glycol esters such as polyethylene glycol monostearate, polyethylene glycol monooleate, polyethylene glycol distearate, and polyethylene glycol dioleate; polyoxyethylene alkyl ethers other than those described above; polyoxyethylene alkyl esters; Polyoxyethylene alkylphenyl ethers; polyoxyethylene alkylphenyl esters and dimethylpolysiloxane polyoxyalkylene copolymer Mention may be made of the body, and the like.

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 reaction product. If it is less than 0.01 part by weight, the effect of uniformizing the size and distribution of the foam after foaming is lacking, and if it exceeds 10 parts by weight, it acts as a plasticizer and lowers the rigidity of the foam.

The phosphoric acid in the present invention is 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 a component that imparts flame retardancy to the resin foam.

Among the above-mentioned phosphoric acids, phosphoric acid has no particular eyesight.
%, 85%, or 89%.

As for polyphosphoric acid, various grades 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 phosphoric acid reacts with the epoxy group of the reaction product of the epoxy resin and is taken into the molecular skeleton of the epoxy resin. Therefore, the amount of the phosphoric acid is controlled to an appropriate amount. By doing so, it is possible to prevent phosphoric acids from remaining as free acids in the obtained foam, and therefore, by controlling so, the epoxy resin-based foam obtained by the present invention can be made of metal, wood, or the like. Even when bonded to other materials,
For example, there is no need for a neutralizing agent to prevent corrosion on metals and discoloration on wood.

On the other hand, phosphoric acid reacts rapidly with the epoxy group of the epoxy resin reaction product, and as described later, both can react simply by being mixed to form a foam. In some cases, the amount of heat generated by 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 obtained.

If there is a possibility of the above, at least one selected from a phosphate having a hydroxyl group bonded to a phosphorus atom and a phosphate ester, together with the phosphoric acid, in order to control the reaction and suppress the heat generation. It is preferable to use a combination of various phosphoric acid compounds (hereinafter, may be simply referred to as a phosphoric acid compound).

In the present invention, by using the above-mentioned phosphoric acid compound in combination, it is possible to control the reaction with the epoxy group to suppress the heat generation and to produce a good foam. 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-mentioned phosphoric acid compound, at least one hydroxyl group bonded to a phosphorus atom is required to react with an epoxy group of an epoxy resin reaction product.
As the phosphoric acid compound, at least one kind of a phosphate or a phosphoric acid ester may be used, but two or more kinds 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 phosphate. Examples thereof include calcium dihydrogen, calcium monohydrogen phosphate, aluminum dihydrogen phosphate, and dialuminum hydrogen phosphate. Examples of the phosphate ester include monomethyl phosphate, dimethyl phosphate, monoethyl phosphate, and diethyl ester. Examples thereof include phosphate, monopropyl phosphate, monoisopropyl phosphate, monobutyl phosphate, monolauryl phosphate, monostearyl phosphate, mono-2-ethylhexyl phosphate, and monoisodecyl phosphate.

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 reaction product of the epoxy resin is 0.4 to 1.0, When the amount of the phosphoric acid used is less than 0.4 in the above ratio, the reaction heat generated by the reaction with the epoxy resin reaction product is small, and the foaming (vaporization) of the foaming agent becomes insufficient. When it is difficult to obtain a foam having an expansion ratio, and when the amount of phosphoric acid used exceeds 1.0 in the above ratio, phosphoric acid often becomes excessive and free in the foam. The rate of remaining as an acid increases, the foaming state of the foam deteriorates, and when the foam comes into contact with metal or wood, the corrosion or discoloration of the foam increases.

It is preferable that the amount of the phosphoric acid used is further appropriately adjusted depending on the use of the foam, the production method, the production conditions, etc., and the workability at the time of foaming, the mechanical strength of the foam, and the heat insulating property. From the viewpoint of uniformity, it is more preferable to use an amount such that the above ratio becomes 0.4 to 0.8.

When the above-mentioned 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 the hydroxyl groups of the phosphoric acid and the phosphoric acid compound to the number of the epoxy groups of the epoxy resin reaction product is 0.4 to 1.0.
And the amount

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 amount of phosphoric acid and phosphoric acid compound is as follows:
When the amount of phosphoric acids is too small, the reactivity with the epoxy resin reaction product may be insufficient, and when a solid phosphoric acid compound is used, It is preferable to use in combination with phosphoric acid or polyphosphoric acid, which is a liquid, in order to facilitate the foaming and hardening, particularly, the fluidity.

In the present invention, the ratio of the number of hydroxyl groups of the phosphoric acid to the number of epoxy groups of the above-mentioned epoxy resin reaction product refers to the number of hydroxyl groups of the phosphoric acid being the number of epoxy groups of the epoxy resin reaction product. The number of epoxy groups in the epoxy resin reaction product is the value obtained by dividing the amount of the epoxy resin reaction product used by the epoxy equivalent of the epoxy resin reaction product. When the epoxy resin reaction product of the above is used, it means the total value obtained by dividing the amount of each epoxy resin reaction product used by the epoxy equivalent of each epoxy resin reaction product.

Further, the number of hydroxyl groups of the phosphoric acid is a value obtained by dividing the amount of the phosphoric acid used by the hydroxyl equivalent of the phosphoric acid.
When two or more phosphoric acids are used, the total value is the sum of the values obtained by dividing the amount of each phosphoric acid used by the hydroxyl equivalent of each phosphoric acid, and the same applies when phosphoric acids and phosphoric acid compounds are used in combination. It is.

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

In the present invention, in addition to the above flame retardants,
Fillers, pigments, and the like may be used for adjusting the fluidity and the like during foaming hardening and for economical effects, and these can be mixed with an epoxy resin or the like according to a standard method.

The reaction product of the epoxy resin and the mixture containing phosphoric acid and others usually react at room temperature. Therefore, in the method for producing the epoxy resin foam of the present invention, the reaction product of the epoxy resin and the phosphoric acid or phosphorus are used. It is preferable that a mixture of an acid and a phosphoric acid compound (hereinafter, may be simply referred to as phosphoric acid or the like) is mixed at room temperature to form a reactive mixture, but the epoxy resin reaction product is a highly viscous liquid. In such cases, the mixing of the epoxy resin reaction product with phosphoric acid or the like can be performed under heating.

The above-mentioned flame retardant, foaming agent and foam stabilizer can be mixed with these at the same time when the above two are mixed. At least one of the two is mixed with a flame retardant, foaming agent or foam stabilizer. It is also possible to mix in advance, and when mixing in advance, for ease of mixing, mix with a component containing an epoxy resin reaction product to prepare a premix,
By mixing this premix with components containing phosphoric acids, etc.,
Preferably, it is a reactive mixture.

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

The reactive mixture containing the reaction product of the epoxy resin, the flame retardant, the foaming agent, the foam stabilizer, the phosphoric acid, etc. can start the reaction at room temperature, and the reaction proceeds while generating heat. It is foamed by the vaporization of the foaming agent, and is cured by reaction to form an epoxy resin-based foam.As a device for mixing and discharging and injecting the mixture, it is usually used for the production of polyurethane resin foam and the like. It is preferred to use a mixing device called a multi-component mixing foamer, as has been described.

As a method of molding the epoxy resin foam obtained by the present invention into a desired shape, there is a method of injection foaming in which the above-mentioned raw material components are mixed and poured into a mold of a desired size and shape to foam and harden. Method, the above-mentioned raw material components are mixed and flowed on a flat surface, and before the mixture is cured, a slab foaming method or the like is employed in which the surface of the mixture during foaming and curing is scraped to a predetermined thickness with a doctor blade or the like, and the mixture is cured. be able to.

The epoxy resin foam obtained according to the present invention can be used for the same applications as conventional resin foams. For example, a foam obtained by a slab foaming method is cut out to obtain a desired foam. 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 shaped heat insulating material also serving as a formwork, a heat insulating material under the floor, and the like.

Further, it can be foamed between an inner wall and an outer wall of a building such as a refrigerated warehouse by an injection foaming method and used as a heat insulating material, or used as a core material of a door or a sandwich panel. Alternatively, a composite material such as synthetic wood can be obtained by impregnating a mixture of the above-mentioned raw material components into a reinforcing fiber such as a glass fiber and performing foaming and curing.

[0079]

The mixture of the epoxy resin reaction product and phosphoric acid or the like reacts rapidly at room temperature to generate heat. By utilizing this reaction heat for vaporizing the foaming agent,
A mixture of an epoxy resin reaction product and phosphoric acid or the like 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 using an epoxy resin reaction product obtained by reacting an aldehyde-based condensable resin having low flammability among organic materials with an epoxy resin, the flame retardancy of the foam can be further enhanced. it can.

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 improve the dimensional stability of the foam. It also improves heat deformation resistance and the like.

Further, since a part of the flame retardant reacts with phosphoric acid and 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. Using the epoxy resin foam obtained by the above as a core material such as a sandwich panel, when this 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 also act as a dehydration and carbonization accelerator when exposed to the above-mentioned high temperatures, and cause 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.

[0085]

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

Example 1 An aldehyde-based condensable resin was prepared by adding 2.2 mol of formaldehyde to 1 mol of melamine to 100 parts by weight of a phenol novolak polyglycidyl ether-based epoxy resin having an epoxy equivalent of 175 g / eq and a molecular weight of about 600. Was mixed at 100 ° C. for 2 hours, and the epoxy equivalent was about 450 g / eq.
A viscous liquid epoxy resin reaction product was obtained. 2 parts by weight of polyoxyethylene sorbitan monostearate as a foam stabilizer with respect to 100 parts by weight of the reaction product,
And, 50 parts by weight of magnesium hydroxide having an average particle diameter of 30 μm as a flame retardant was added and kneaded using a three-roll kneader, and further, 1,1-dichloro-2 as a foaming agent was added.
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 used as a Y component and placed in another raw material tank.

Each component of X and Y is represented by X: Y = 100: 4.8.
At a discharge weight ratio of 3 kg / min into the mixing head of the multi-component mixing and foaming machine to discharge the reactive mixture. This corresponds to a ratio of the total number of hydroxyl groups of phosphoric acid and phenylphosphonic acid to the number of epoxy groups of the epoxy resin reaction product of 1.0. 3750 g of this reactive mixture is immediately added to 500 × 500 × 100
When placed in a metal frame at room temperature of
Starting at 0 seconds, the foam hardening was completed after 2 minutes and 30 seconds.

Comparative Example 1 An aldehyde condensable resin obtained by adding 2.2 mol of formaldehyde to 1 mol of melamine to 100 parts by weight of a phenol novolak polyglycidyl ether epoxy resin having an epoxy equivalent of 175 g / eq and a molecular weight of about 600 Was mixed at 100 ° C. for 2 hours, and the epoxy equivalent was about 450 g / eq.
A viscous liquid epoxy resin reaction product was obtained. 2 parts by weight of polyoxyethylene sorbitan monostearate as a foam stabilizer with respect to 100 parts by weight of the reaction product,
And, 150 parts by weight of magnesium hydroxide having an average particle diameter of 30 μm as a flame retardant is added, and the mixture is kneaded using a three-roll kneader. Further, 1,1-dichloro-
What added 20 parts by weight of 2,2,3,3,3-pentafluoropropane was designated as X component, and was put in a raw material tank of a multi-component mixing foaming machine. Next, an industrial 89% phosphoric acid and phenylphosphonic acid were mixed in a molar ratio of 1: 1, and a weight ratio of 0.7: 1.
Was mixed as a Y component and placed in another raw material tank.

X: Y = 100: 7.2
At a discharge weight ratio of 3 kg / min into the mixing head of the multi-component mixing and foaming machine to discharge the reactive mixture. This corresponds to a ratio of the total number of hydroxyl groups of phosphoric acid and phenylphosphonic acid to the number of epoxy groups of the above epoxy resin reaction product of 1.5. 3750 g of this reactive mixture is immediately added to 500 × 500 × 100
When placed in a metal frame at room temperature of
Starting at 0 seconds, the foam hardening was completed after 2 minutes and 30 seconds. However, the obtained foam had non-uniform cell size and distribution, and also had large cavities inside.

Comparative Example 2 Dimethylpolysiloxane polyalkylene copolymer 2 as a foam stabilizer was added to 100 parts by weight of a resole type phenol resin.
Parts by weight, and 100 parts by weight of aluminum hydroxide having an average particle diameter of 30 μm as a flame retardant, and kneaded using a three-roll kneader. Further, 1,1-dichloro-1-fluoroethane as a foaming agent is added. The mixture to which 20 parts by weight had been added was designated as X component, and the mixture was placed in a raw material tank of a multi-component mixed foaming machine.
Next, a 60% aqueous solution of phenylphosphonic acid was charged into another raw material tank as a Y component.

The X and Y components were fed into the mixing head of the multi-component mixing and foaming machine at a discharge weight ratio of X: Y = 100: 15 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 in the above Examples and Comparative Examples are shown in Table 1 below.

[0093]

[Table 1]

[0094]

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.

The epoxy resin foam obtained according to the present invention has phosphoric acid and the like 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. By using a reaction product of an epoxy resin and an aldehyde-based condensable resin, a larger amount of the flame retardant can be uniformly dispersed in the foam.
Excellent flame retardancy and fire resistance.

──────────────────────────────────────────────────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 E in the following quantitative ratios. A: obtained by reacting an epoxy resin having two or more epoxy groups in a molecule with an aldehyde-based condensable resin;
Liquid reaction product having an epoxy equivalent of 2000 g / eq or less: 100 parts by weight B: at least one flame retardant selected from metal hydroxides and metal oxide hydrates: 10 to 300 parts by weight C: foaming Agent: 1 to 50 parts by weight D: foam stabilizer: 0.01 to 10 parts by weight E: at least one phosphoric acid selected from phosphoric acid, polyphosphoric acid and phenylphosphonic acid An amount such that the ratio of the number of hydroxyl groups to the number of epoxy groups in the reaction product 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 E ′ in the following quantitative ratios. A: obtained by reacting an epoxy resin having two or more epoxy groups in a molecule with an aldehyde-based condensable resin;
Liquid reaction product having an epoxy equivalent of 2000 g / eq or less: 100 parts by weight B: at least one flame retardant selected from metal hydroxides and metal oxide hydrates: 10 to 300 parts by weight C: foaming Agent: 1 to 50 parts by weight D: foam stabilizer: 0.01 to 10 parts by weight E ': at least one kind of phosphoric acid selected from phosphoric acid, polyphosphoric acid and phenylphosphonic acid, and a phosphorus atom A mixture comprising at least one phosphoric acid compound selected from a phosphate salt and a phosphoric acid ester having a bound hydroxyl group: the total number of the phosphoric acids and the hydroxyl groups of the phosphoric acid compound in the mixture, and the number of epoxy groups of the reaction product The ratio of which is 0.4 to 1.0 with respect to the number of 3. A liquid reaction product having an epoxy equivalent of 2,000 g / eq or less is obtained by reacting 100 parts by weight of an epoxy resin with 1 to 100 parts by weight of an aldehyde-based condensable resin. 3. The method for producing an epoxy resin-based foam according to item 1. 4. The epoxy resin foam according to claim 1, wherein the epoxy resin is at least one selected from a glycidyl ether epoxy resin, a glycidyl ester epoxy resin, and a cycloaliphatic epoxy resin. Manufacturing method. 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.