JPH0781025B2 - Method for producing epoxy foam - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing an epoxy foam, more specifically, a foam having a uniform foaming state and a flexible foam without using a usual foaming agent. A method for manufacturing.

TECHNICAL BACKGROUND OF THE INVENTION AND ITS PROBLEMS Conventionally, as a method for producing an epoxy foam, a gas such as air or a low boiling point compound such as pentane is introduced as a foaming agent into a system composed of an epoxy resin and a curing agent. A method for causing foaming by reacting at room temperature has been known. Also,
A method has also been known in which a foaming agent such as azobisisobutyronitrile or azodicarbonamide is added to a system composed of an epoxy resin and a curing agent, and the mixture is heated to a predetermined temperature to foam.

However, the epoxy foam manufactured by the above-mentioned conventional method has a weak point that it is hard and brittle because the foaming state inside is uneven. Therefore, the conventional epoxy foam has poor mechanical durability, its application range is limited, and it is a major problem that it can not exhibit sufficient functions when used as a metal anticorrosion agent, heat insulating material, shock absorber. There was a point.

Therefore, it has been desired to develop an epoxy foam having a uniform foaming state inside, excellent mechanical properties, and excellent heat resistance and adhesiveness.

OBJECT OF THE INVENTION The present invention is intended to solve the above-mentioned problems, in which the foaming state inside is uniform, and has strong flexibility against compression, bending, or bending, and a metal corrosion inhibitor, An object of the present invention is to provide a method for producing an epoxy foam having high mechanical durability when used as a heat insulating material, a shock absorber and the like.

SUMMARY OF THE INVENTION A method for producing an epoxy foam according to the present invention comprises a polyepoxy compound having two or more epoxy groups in one molecule,
It is characterized in that a carbonate oligomer having a phenolic hydroxyl group at the terminal and a reaction catalyst are reacted at a temperature of 120 ° C to 240 ° C.

In the present invention, the carbonate oligomer serves as a crosslinking component and releases carbon dioxide during the reaction, and this carbon dioxide serves as a foaming agent. For this reason, the foamed product obtained has a uniform foaming state, and is superior in flexibility, heat resistance and adhesiveness as compared with the epoxy foam produced by the conventional production method.

Further, since it is not necessary to newly add a foaming agent in addition to the polyepoxy compound and the carbonate oligomer, the manufacturing process is simplified and it is economical.

Detailed Description of the Invention Regarding the method for producing an epoxy foam according to the present invention,
This will be specifically described.

Polyepoxy compound In the present invention, one of the components for producing an epoxy foam is
As one example, a polyepoxy compound having two or more epoxy groups in one molecule is used.

Specific examples of this polyepoxy compound include epoxy resins obtained from bisphenol A, tetrabromobisphenol A, bisphenol F, bisphenol aldehyde, and epichlorohydrin.

Examples of other useful polyepoxy compounds include polyglycidyl ethers and polyglycidyl esters such as polyphenols, resorcin, hydroquinone, phthalic acid, polyalkylene glycol, and phenol novolac.

These polyepoxy compounds are usually 0.1-0.8% by weight
Of the α-diol that contains the water of
It contains 3 to 20 millimoles in 100 g, that is, about 5 to 15% by weight.

It is considered that such water or α-diols are involved in the reaction during the production reaction of the epoxy foam according to the present invention.

When a polyepoxy compound which is in a dry state and does not contain water and α-diol is used, water or α-diol may be added at the time of mixing with a carbonate oligomer described later.

Carbonate Oligomer In the present invention, a carbonate oligomer having a phenolic hydroxyl group at the end is used as another component for producing an epoxy foam.

Such a carbonate oligomer is usually represented by the following formula.

(In the formula, Ar is a divalent phenol residue of a phenyl group or bisphenyl, and n obtained by ¹³ C NMR analysis is 0.
-20, and the hydroxyl equivalent is 100-2800. ) Such a carbonate oligomer is used in an amount of 1 to 60 parts by weight, preferably 5 to 3 parts by weight, based on 100 parts by weight of the polyepoxy compound.
Used in an amount of 0 parts by weight.

Reaction catalyst Furthermore, 0.05 to 5.0 parts by weight of the reaction catalyst is added to the epoxy resin.

Examples of the reaction catalyst include tertiary amines, imidazoles, onium salts, trialkylphosphines, triarylphosphines and the like. That is, specifically, 2-methylimidazole, imidazoles such as 2-ethyl-4-methylimidazole, choline chloride, onium salts such as tetramethylammonium chlorides, tris (N, N-dimethylaminomethyl) phenol, N, N-benzylmethylamine, 1,8-diazabicyclo (5.4.0) undecene and its derivatives, and tri-N
-Propylphosphine, tri-N-butylphosphine,
Triphenylphosphine or the like is used.

Reaction auxiliaries Adding 0.01 to 1 part by weight of α-diol and water as reaction auxiliaries may result in an increase in the foaming amount of the epoxy foam and may be preferable. Examples of the α-diol include alkylene glycol.

Effective auxiliary agents other than α-diol and water include polyol compounds having adjacent hydroxyl groups such as glycerin.

Other compounding agents As required, calcium carbonate, talc,
Addition of barium sulfate, titanium dioxide, or the like in an amount of 200 parts by weight or less may lead to modification of the epoxy foam produced and may be preferable.

Further, it is preferable to add an acrylic flow regulator and a silicone foam stabilizer together with the polyepoxy compound and the oligomer.

Foaming method The polyepoxy compound, the carbonate oligomer, the reaction catalyst and the like are mixed by rolling within a temperature range of 70 ° C to 130 ° C when the polyepoxy compound and the like are in powder form. Mixing time is within 5 minutes, and immediately after mixing, it is cooled to room temperature. When the polyepoxy compound or the like is liquid, it may be stirred.

The reaction is performed under normal pressure or increased pressure. Reaction temperature is 120
Set the temperature to ℃ to 240 ℃, and perform it for 5 to 40 minutes. In particular, it is preferable to carry out the reaction at a temperature of 140 ° C to 180 ° C for 10 minutes to 30 minutes.

When the polyepoxy compound is a liquid, the base material is coated or impregnated with the mixture of raw materials or poured into a mold,
The raw material mixture is heated to a predetermined temperature together with the base material or the mold to foam. When the polyepoxy compound is a powder, the mixture of the raw materials is electrostatically or fluidly coated on the base material, or fitted into a mold, and the mixture of the raw materials is heated together with the base material or the mold to foam.

As described above, in the present invention, the carbonate oligomer reacts with the epoxy compound by heating, crosslinks and copolymerizes, and releases carbon dioxide. The carbon dioxide generated at this time causes the copolymer to foam during the manufacturing process. In the present invention, since carbon dioxide is released from the oligomer itself which causes copolymerization, the foaming state becomes more uniform as compared with the conventional manufacturing method in which a foaming agent is newly added, and the obtained epoxy foam has flexibility and flexibility. Excellent in mechanical properties.

Further, the density of the epoxy foam obtained by the above-mentioned manufacturing method is different depending on the blending amount of the carbonate oligomer, 0.05
It will be in the range of up to 1.18 g / cm ² . Moreover, the epoxy foam obtained by the present invention has excellent adhesiveness to metal, and when the one adhered to the metal is peeled off, a part of the epoxy foam is destroyed. The epoxy foam obtained in the present invention has a thermal conductivity of 0.01 to 0.5 Kcal / mh ° C and can be used as a heat insulating material.

The foaming rate can be changed by the blending amount of the carbonate oligomer.

EFFECT OF THE INVENTION In the present invention, when an epoxy foam is produced by the reaction of a polyepoxy compound and a carbonate oligomer, the oligomer serves as a crosslinking component of the epoxy compound and a foaming component in the epoxy foam production process, and carbon dioxide To release. Therefore, as compared with the conventional manufacturing method in which a foaming agent is added in addition to the epoxy resin and the curing agent, the foaming state inside the foam is made uniform. Therefore, as compared with the epoxy foam produced by the conventional production method, the epoxy foam produced by the method of the present invention has an effect that hardness and brittleness are improved. That is, the epoxy foam produced by the method of the present invention has excellent heat resistance and adhesiveness, and further has excellent mechanical durability. Therefore, the epoxy foam obtained by the present invention is a damping material, a corrosion inhibitor, a heat insulating material,
It can be used as a shock absorber or an adhesive.

Further, in the manufacturing process of the foam according to the present invention, it is not necessary to add a foaming agent in addition to the polyepoxy compound and the crosslinking agent, so that the manufacturing process can be simplified as compared with the conventional manufacturing method.

Examples will be described below, but the present invention is not limited to these examples.

Example 1 Bisphenol A having an epoxy equivalent of 920 and a softening point of 95 ° C.
Type solid epoxy resin 100 parts by weight, hydroxyl group equivalent 320, softening point 76 ° C, and bisphenol A carbonate oligomer represented by the following [I]: (In the formula [I], the average value of n = 0.62) 30 parts by weight, 0.5 parts by weight of 2-methyl-imidazole as a reaction catalyst, 0.5 parts by weight of an acrylic flow control agent, and a silicone type foam stabilizer. 0.1 part by weight was blended, and the resulting mixture was kneaded with an 8-inch roll heated to 110 ° C. for 3 minutes. Then, after cooling to room temperature, the obtained kneaded product was pulverized to prepare a powdery mixture having a 150 mesh.

The powdery mixture obtained below was foamed by two methods (a) and (b).

(A) 100 cm of the powdery mixture, 10 cm x with a release agent sprinkled
It was filled in a mold container of 10 cm × 5 cm and heated at 150 ° C. for 30 minutes to produce a foamed product having the shape of the mold container.

The epoxy-based foam thus obtained had uniform closed cells, the foam did not break even when compressed, and the flexural load flexural load was 6.0 mm, which was extremely large.

On the other hand, the flexural load of the epoxy foam obtained in Comparative Example 1 (c) described below was 2.6 mm.
Is.

Table 1 shows the measurement results of various physical properties of the epoxy foam obtained as described above.

(B) 0.5m of the powder mixture obtained by sieving above on a 1mm thick iron plate preheated to 130 ° C using an electrostatic coating machine
It is applied to a film thickness of m, and then the coating film at 150 ° C together with the iron plate.
Heated for 15 minutes. As a result, a highly flexible foam coating having a thickness of about 2.5 mm was obtained on the iron plate.

The surface of the obtained foamed coating film was smooth, and the cross-section of the coating film exhibited an extremely uniform foaming state.

Table 2 shows the measurement results of various physical properties of the epoxy foam obtained as described above.

Example 2 Bisphenol A having an epoxy equivalent of 920 and a softening point of 95 ° C.
100 parts by weight of a solid epoxy resin, a hydroxyl equivalent of 653, a softening point of 101 ° C., and a bisphenol A-based carbonate oligomer represented by the above formula [I] (average value of n in the formula [I] = 3.24) An 8-inch heating roll in which 62 parts by weight, 1.0 part by weight of triphenylphosphine as a reaction catalyst, 0.5 part by weight of a flow control agent and 0.1 part by weight of a foam stabilizer were mixed, and the resulting mixture was set at 110 ° C. And kneaded for 2.5 minutes. Then, after kneading, the mixture was immediately cooled to room temperature to prepare a powdery mixture passing through 100 mesh.

The powdery mixture thus obtained was used in Example 1 (a).
It was foamed in the same manner as.

Table 1 shows the results of measurement of various physical properties of the epoxy foam obtained as described above.

Example 3 In Example 2 except that 70 parts by weight of powdered silicon dioxide was further added as a filler to the bisphenol A type solid epoxy resin, carbonate oligomer, triphenylphosphine, flow control agent and foam stabilizer. An epoxy foam was produced in the same manner as in Example 2.

Table 1 shows the results of measurement of various physical properties of the epoxy foam obtained as described above.

Example 4 50 parts by weight of an epoxy resin which is a tetrabromobisphenol A type having an epoxy equivalent of 690 and a brom content of 23% by weight, bisphenol A having an epoxy equivalent of 820 and a softening point of 88 ° C.
30 parts of the same bisphenol A-based carbonate oligomer (average value of n in formula [I] = 0.62) used in Example 1 having 50 parts by weight of epoxy resin of the type, hydroxyl equivalent of 320, and softening point of 76 ° C. Parts by weight, 50 parts by weight of powdered silica dioxide treated with a coupling agent, 3.0 parts by weight of antimony trioxide, 1.0 part by weight of 2-ethyl-4-methylimidazole as a reaction catalyst, and 0.1 part of a silicon-based foam stabilizer. Parts were mixed and kneaded with two 8-inch heating rolls set at 110 ° C. for 3 minutes. After cooling to room temperature, it was pulverized, and this powder was foamed by the method of Example 1 (a).

When the flame retardant V value was measured, the value was 0.

Table 1 shows the results of measurement of various physical properties of the epoxy foam obtained as described above.

Example 5 Epoxy equivalent of 189, 85 parts by weight of liquid bisphenol A type epoxy resin having a viscosity of 130 poise at 25 ° C., 15 parts by weight of reactive diluent (trade name Mitsui Petrochemical R-093), hydroxyl equivalent of 300, 20 parts by weight of a bisphenol A-based carbonate oligomer represented by the above formula [I] having a softening point of 72 ° C. (in the formula [I], the average value of n = 0.46), 2-ethyl-4-methyl as a reaction catalyst. 2 parts by weight of imidazole (trade name: Shikoku Kasei 2E4MZ) and 0.1 part by weight of a silicone type foam stabilizer were added to a beaker and heated to 70 ° C. for dissolution and mixing.

The resulting mixture is a liquid of approximately 10 poise at 70 ° C and is castable. 200g of this mixture heated to 70 ° C
Is poured into a mold of 10 cm x 10 cm x 5 cm preheated to 150 ° C,
It was heated for 40 minutes in an oven set at 150 ° C. As a result, an epoxy foam having a size close to the mold capacity was obtained.

Table 1 shows the results of measurement of various physical properties of the epoxy foam obtained as described above.

Example 6 100 parts by weight of a phthalic acid type liquid epoxy resin having an epoxy equivalent of 193 and a viscosity of 3800 centipoise, a hydroxyl equivalent of 300, and a softening point of 72 ° C. The same bisphenol A-based carbonate oligomer as in Example 5 (formula [I]).
In the beaker, 15 parts by weight of the average value of n = 0.46), 1 part by weight of tris (N, N-dimethylaminomethyl) phenol as a reaction catalyst, and 0.1 part by weight of a silicon-based foam stabilizer were added to a beaker. The mixture was heated to ℃ and dissolved and mixed.

The obtained mixture was a liquid of about 6 poises at 70 ° C., 200 g of the mixture was cast in a mold as in Example 5, and then heated in an oven at 150 ° C. for 40 minutes to foam. .

Table 1 shows the results of measurement of various physical properties of the epoxy foam obtained as described above.

Comparative Example 1 Bisphenol A having an epoxy equivalent of 920 and a softening point of 95 ° C.
100 parts by weight of epoxy resin, 5 parts by weight of dicyandiamide as a cross-linking agent, dinitrosopentamethylenetetramine as a foaming agent /
Urea compound (Brand name Eiwa Kasei Cellular / Cell Paste
5 parts by weight of K5), 1 part by weight of 2-methylimidazole as a reaction catalyst, 0.1 part by weight of a silicon-based foam stabilizer, and 0.5 part by weight of an acrylic flow regulator, and mixed at 110 ° C.
The mixture was kneaded for 3 minutes with an 8-inch roll heated to 1.

After cooling to room temperature, the mixture was pulverized and sieved to prepare a powdery mixture that passed through 150 mesh.

The resulting powdery mixture was foamed by the following two methods (c) and (d).

(C) 100 g of the sieved powder mixture was foamed in the same manner as in Example 1 (a) above.

Table 2 shows the measurement results of various physical properties of the epoxy foam obtained as described above.

(D) On a 1 mm iron plate preheated to 130 ° C, the powdered mixture which has been sieved is applied to a film thickness of 0.35 mm by using an electrostatic coating machine, and then the coating film is applied together with the iron plate at 150 ° C for 15 minutes. Heated. As a result, a foamed coating having a thickness of about 2.5 mm was obtained.

Table 2 shows the measurement results of various physical properties of the epoxy foam obtained as described above.

Comparative Example 2 85 parts by weight of a liquid bisphenol A type epoxy resin having an epoxy equivalent of 189 and a viscosity of 130 poise at 25 ° C., 15 parts by weight of a reactive diluent (trade name Mitsui Petrochemical R-093) as a reaction catalyst. 4 parts by weight of 2-ethyl-4-methylimidazole (trade name: Shikoku Kasei 2E4MZ), 3 parts by weight of azodicarbonamide / urea compound (trade name: Eiwa Kasei Vinylol AC / Cell Paste 101) as a foaming agent, and a silicone-based preparation. 0.1 parts by weight of foam was added to the beaker and mixed.

200 g of the obtained mixture was foamed in a mold preheated to 150 ° C. in the same manner as in Example 5.

Table 1 shows the measurement results of various physical properties of the epoxy foam thus obtained.

Example 7 According to Example 1, except that the content of the carbonate oligomer was 40 parts by weight, 15 parts by weight, and 7.5 parts by weight, three kinds of powders passing through 150 mesh were prepared.

These three types of powder were heated and foamed in the same manner as in Example 1.

The results of measuring the expansion ratio, density, bending strength, bending modulus, compressive strength and thermal conductivity of each foam,
It shows in Table 3 with the result measured about the foam of Example 1 (a).

From this, it is understood that the expansion ratio can be changed by the blending amount of carbonate.

In addition, in order to increase the expansion ratio with 30 parts by weight or more,
-Need a reaction aid such as diol, syrup.

Claims (1)

[Claims] 1. A polyepoxy compound having two or more epoxy groups in one molecule, a carbonate oligomer having a terminal phenolic hydroxyl group, and a reaction catalyst at 120 ° C. to 2 ° C.
A method for producing an epoxy foam, which comprises reacting at a temperature of 40 ° C.