JP3153045B2 - Composite foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel composite foam which is particularly useful as a heat insulating material and also used as a structural material and a soundproofing material.

[0002]

2. Description of the Related Art Phenol, phenol urethane,
Curable resin foams typified by urethane and / or nullate-based and epoxy-based resins are widely used for various heat-insulating applications, like thermoplastic resin foams typified by polystyrene-based and polyethylene-based resins. However, the curable resin foam is brittle and has low mechanical strength, and has a large density difference (generated between the surface layer portion and the core layer portion) caused by voids generated by reaction heat during foaming hardening and foaming pressure. . For this reason, there is a problem that commercialization of a bulky foam is generally difficult, and improvement thereof has been strongly demanded.

In recent years, as the use of non-fluorocarbon insulation materials has been progressing from the viewpoint of global environmental protection, for example, foams made of, for example, carbon dioxide gas have been inevitably reduced, and the heat insulation performance has been further sacrificed. is there.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to maintain the heat resistance and / or flame resistance inherent in a curable resin foam, to have improved heat insulating performance and mechanical strength, and to further improve the surface layer portion. To provide a composite foam having a small density difference between the core and the core layer and containing no voids.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have come to a combination of a foamable curable resin composition and polyvinylidene chloride-based foamed particles, and have further developed this idea. Based on the above, the present invention was completed.

That is, the present invention is a composite foam comprising a cured resin foam structure containing polyvinylidene chloride-based expanded particles.

[0007] The polyvinylidene chloride-based expanded particles (hereinafter simply referred to as “expanded particles”) used in the present invention are:
For example, Japanese Patent Publication No. Sho 63-33781 and Japanese Patent Publication No. Sho 63-3
No. 3,782, JP-A-63-170435, etc., obtained by reacting 10 to 85% by weight of vinylidene chloride monomer with 15 to 90% by weight of another copolymerizable monomer. Amorphous vinylidene chloride-based copolymer resin particles obtained by impregnating a foaming agent and then foaming to a desired expansion ratio are tough foamed particles. As a representative example suitably used in the present invention, Asahi Kasei Cellmore (trade name) commercially available from Kogyo Co., Ltd. may be mentioned. The particle size and expansion ratio of the expanded particles are arbitrarily selected depending on the purpose of use, but generally the particle size is 0.1 to 8 mm, preferably 0.5 to 6 mm, and the expansion ratio is 10%.
の も の 100 times are used. The particle diameter is 0.1
If it is less than mm, the specific surface area increases, so that a large amount of the foamable curable resin composition is required, and it is difficult to reduce the density of the composite foam. Conversely, if it exceeds 8 mm, the uniform mixing of the composition and the foamed particles tends to be impaired. If the expansion ratio is less than 10 times, the density of the composite foam becomes too high, and if it exceeds 100 times, the mechanical strength tends to decrease.

In order to improve the wettability with the foamable curable resin composition, the foamed particles are previously coated with a curable resin such as a phenol resin or an epoxy resin, or an organic solvent such as methylene chloride. It can be used after processing.

The foamable curable resin composition (hereinafter simply referred to as "foamable composition") used in the present invention foams and cures at room temperature and / or under heating to form a cured structure having a cellular structure. together with the those having a foamed particles and properties combined to form a molded article of a fiber base material curing tissue later used as required, in particular off
Enol urethane foamable composition, preferably from the viewpoint of heat resistance and flame resistance, at least a liquid phenol resin and a polyisocyanate compound or a derivative derived therefrom.
Prepolymer-type modified product or Nurate-type modified product
Phenol which is constituted by a combination of a curing agent and blowing agent comprising
A Lumpur urethane foam composition. The blending ratio of the foamable composition and the foamed particles is selected in consideration of the properties and applications required for the composite foam, and thus cannot be unconditionally limited. 90/10
(Weight ratio).

As the liquid phenolic resin, phenols and aldehydes, for example, 1 mole or more of aldehydes per mole of phenols, preferably 1 to 3 moles.
Initial condensation products obtained by reacting in the presence of a reaction catalyst at a molar ratio, specifically resol type, ammonia resol type, novolak resol type and benzyl ether type phenolic resin, or ethylene oxide to these phenolic resins, Alkylene oxides such as propylene oxide, ethylene carbonate, cyclic carbonates such as propylene carbonate, epoxy compounds, melamine compounds, modified phenolic resins obtained by reacting or mixing a guanamine compound, and the like. However, the present invention is not limited to this. Among them, resol type and benzyl ether type phenol resins and modified phenol resins thereof are particularly preferable. Such phenol resins may be used alone or in combination of two or more. Further, if necessary, a novolak type phenol resin can be used in combination.

Examples of the phenols include phenol, alkylphenols such as cresol, xylenol, nonylphenol, pt-butylphenol, polyphenols such as resorcinol and catechol, bisphenol A and bisphenol F. Such as bisphenol, cresol residue, resorcinol residue and bisphenol A residue. On the other hand, examples of aldehydes include formaldehyde such as glyoxal and furfural, as well as formaldehyde such as formalin and paraformaldehyde.
Examples of the reaction catalyst include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, sodium bicarbonate, barium hydroxide, calcium hydroxide, magnesium oxide, ammonia, hexamethylenetetramine, triethylamine, and triethanolamine. And acidic divalent metal salts such as lead naphthenate, zinc acetate, zinc borate and zinc chloride. These phenols, aldehydes and reaction catalysts may be used alone or in combination of two or more.

Further, the curing agent is a compound having a reactive functional group that occurs a curing reaction with a compound or a liquid phenolic resin to accelerate the curing reaction of the liquid phenolic resin itself, as suitable examples, the molecular Polyisocyanate compounds having two or more isocyanate groups therein, such as tolylene diisocyanate (TDI), crude TD
I, aromatic polyisocyanates such as xylylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate (crude MDI), alicyclic polyisocyanates such as isophorone diisocyanate, and fats such as hexamethylene diisocyanate In addition to the group III polyisocyanate, a modified prepolymer having an isocyanate group obtained by reacting a polyisocyanate with a polyol, or a nurate-type modified polyisocyanate may be used. These curing agents may be used alone or in combination of two or more. The amount of the curing agent used varies depending on the curing mode and the type of the curing agent.
Ru 0.5 to 500 parts by weight of Der relative to the weight part.

The foaming agent enhances mechanical strength by promoting filling of voids between the foamed particles and the fibrous base material by the curable resin composition, and forms bubbles in the cured structure to impart heat insulation. . Examples of such blowing agents include pentane, aliphatic hydrocarbons such as hexane, diethyl ether, aliphatic ethers such as diisopropyl ether,
1,1-dichloro-1-fluoroethane (HCFC-1
41b), 1,2-dichloro-2,2,2-trifluoroethane (HCFC-123), halogenated hydrocarbons such as methylene chloride and propyl chloride, perfluorocarbons such as perfluorohexane and perfluoropentane Physical blowing agents represented by, or sodium hydrogen carbonate, sodium carbonate, barium carbonate, calcium carbonate, hydrogen peroxide that chemically generates nitrogen and carbon dioxide,
Chemical blowing agents represented by water, paratoluenesulfonyl hydrazide, 4,4-oxybisbenzenesulfonyl hydrazide, azodicarbonamide, azobisisobutyronitrile, or air, nitrogen, carbon dioxide, butane Gas bodies. These blowing agents
They may be used alone or in combination of two or more. The amount of the foaming agent varies depending on the density of the composite foam and the type of the foaming agent, but is generally 1 to 50 parts by weight based on 100 parts by weight of the liquid phenol resin.

The reinforcing fiber substrate used in connection with the present invention includes aramid fiber, phenol fiber,
Examples thereof include carbon fiber, glass fiber, rock wool fiber, stainless steel fiber, and aluminum fiber. This fiber substrate is
In view of the effect of imparting toughness, the fiber length is preferably 1 to 1
Those having a diameter of 00 mm, more preferably 1 to 70 mm are used. The amount of the fibrous base material used is determined according to the required properties and applications. Generally, the proportion of the composite material in the composite material is preferably in the range of 1 to 30% by weight, and more preferably 5 to 30% by weight.
30% by weight.

Next, a preferred method for producing the composite foam of the present invention will be described. First, a method of mixing the foaming particles and the fiber base material used as necessary with the curing agent, and then adding a liquid phenol resin, a foaming agent and other additives as necessary, or further mixing the foaming particles and the liquid After mixing a phenolic resin, a curing agent, a foaming agent and other additives that are added as necessary, by further adding and mixing a fiber base material, the expanded particles and the fiber base material are coated with an expandable composition. To produce a composite material. At this time, it is preferable to use the foamed particles and the fibrous base material, particularly the foamed particles, by preheating them to a temperature of 130 ° C. or less at which there is no possibility that the foamed particles shrink. When mixing the components, it does not matter whether a batch-type or continuous-type mixer is used, but it is preferable to use a mixer that rotates at a high speed as much as possible. The use of a machine is preferred.

Next, the obtained composite material is immediately poured into a molding frame or a mold (hereinafter, simply referred to as “molding frame or the like”), and is preferably further pressurized to obtain a better filling state. You. However, the degree of pressure filling may be arbitrarily changed according to the form and quality specifications of the molding frame or the like, but preferably the pressure is within the extent that the foamed particles have restorability, for example, 8 kg / cm ² or less. Pressurize with pressure. In the case of integrally molding with the molding frame itself, if an adhesive is applied to the molding frame in advance and pressure is applied, steps such as bonding can be omitted.

The composite material filled in the molding frame or the like in this way has the property of foaming and hardening with self-heating if left at room temperature as it is to form a composite foam. In order to promote the formation, a method of obtaining a composite foam by heating and desirably heating at a temperature of preferably 130 ° C. or lower and under pressure to obtain a composite foam is employed.

The composite foam of the present invention thus obtained is
Has good insulation performance, mechanical strength and heat and flame resistance,
In addition, since it has a small density difference and high quality reliability without voids, it is used as a heat insulating material for ships, buildings, vehicles, etc., as well as structural materials for civil engineering, soundproofing materials, etc. Can also be used widely.

In the production of the composite foam of the present invention, if necessary, various additives such as polysiloxane / oxyalkylene copolymer, polyoxyethylene sorbitan fatty acid ester and castor oil / ethylene oxide adduct Foam stabilizers represented by nonionic surfactants such as triethylenediamine, phenylpropylpyridine, ethylmorpholine, dibutyltin dilaurate, dibutyltin diacetate, lead naphthenate, cobalt naphthenate, potassium acetate, and hexahydrotriazine. Catalyst for promoting a urethane-forming reaction and / or a nullation reaction, γ-aminopropyltriethoxysilane,
In addition to silane coupling agents represented by γ-glycidoxypropyltriethoxysilane, etc., flame retardants represented by aluminum hydroxide, melamine, zinc borate, phosphorus-containing compounds, halogen-containing compounds, reactive diluents, plasticizers Agents, coloring agents and the like can be used.

[0020]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. The density of the composite foam is JIS-A-95.
14. The bending strength complies with ASTM C-203, and the thermal conductivity is Kemtherm QTM- manufactured by Kyoto Electronics Industry Co., Ltd.
It was measured with a D3 type thermal conductivity meter, and the presence or absence of voids was visually determined. Liquid phenolic resins I and II produced according to the following Reference Examples were used as the curable resin.

REFERENCE EXAMPLE 1 300 kg of phenol, 150 kg of 92% by weight paraformaldehyde and 4 kg of lead naphthenate were charged into a reaction vessel equipped with a stirrer, thermometer and reflux condenser, and the mixture was stirred for about one hour. The temperature was raised to the reflux temperature, and the reaction was further performed under reflux for 2.5 hours to obtain a reaction product, to which 180 kg of water was added to prepare a mixture. The mixture was then poured into a jacketed tubular reactor (length / inner diameter = 10
00, from the raw material supply port with a mantle vapor pressure of 3 kg / cm ² )
Water and unreacted monomers are separated and removed by a continuous evaporator (temperature in the can: about 120 ° C, degree of vacuum: about 100 mmHg) connected to the reactor and continuously supplied at a flow rate of 0 kg / Hr. A liquid benzyl ether type phenol resin I of 500 mgKOH / g was obtained.

[0022]

Example 1 600 g of expanded particles (Cellmore, trade name: 50 times, expansion ratio: 50 times, particle size: 2 to 5 mm, manufactured by Asahi Kasei Kogyo Co., Ltd.) in a 30 L super mixer manufactured by Taiyo Casting Machine Co., Ltd.
And foamable composition 60 composed of the composition ratios shown in Table 1.
0 g and mixed at room temperature for 15 seconds to prepare a composite material. Next, the composite material is placed in a mold (25 × 25 × 25).
cm), the upper mold was placed, and the mixture was pressure-filled with a press, and further foam-hardened at room temperature under a pressure of ² kg / cm ² to obtain a phenol-urethane-based composite foam. With respect to this composite foam, the density (surface layer portion and core layer portion), bending strength, and thermal conductivity were measured by the above-described test method. Table 1 shows the results. Also, this composite foam does not contain voids,
In addition, it exhibited excellent self-extinguishing properties even when ignited, and had good heat resistance, such as maintaining its shape even in a carbonized state.

(Example 2) Preparation and physical properties of a phenolurethane-based composite foam in the same manner as in Example 1 except that foamed particles preheated to 50 ° C were used and the molding temperature was set to 50 ° C. Was measured. Table 1 shows the measurement results. In addition, this composite foam did not contain voids, and had excellent self-extinguishing properties and good heat resistance.

(Example 3) In Example 2, foamed particles preheated to 50 ° C (Cellmore, trade name: 35 times, Asahi Kasei Kogyo Co., Ltd., expansion ratio 35 times, particle size 1 to 4 mm) were used. Preparation of a phenol-urethane-based composite foam and measurement of physical properties were performed in the same manner as in Example 2 except that the blending ratio of the foam and the foamable composition was changed to 60/40 (weight ratio). Table 1 shows the measurement results. In addition, this composite foam did not contain voids, and had excellent self-extinguishing properties and good heat resistance.

Example 4 Expanded particles preheated to 50 ° C. in a 30 L supermixer manufactured by Taiyo Casting Machine Co., Ltd. (Cellmore, trade name, manufactured by Asahi Chemical Industry Co., Ltd., expansion ratio 35 times, particle size 1)
４4 mm) 600 g, an expandable composition 600 g having a composition ratio shown in Table 1, and a chopped strand (glass fiber manufactured by Central Glass Co., Ltd., trade name: ESC-25-1675) having a fiber length of 25 mm (120 g) were charged. 15 at room temperature
The composite was prepared by mixing for 2 seconds. Next, after pouring this composite material into a mold (25 × 25 × 25 cm), the upper mold is placed and filled with a press under pressure, and further at 50 ° C. and 2 kg / cm.
^The mixture was foam-cured under the pressure of ² to obtain a phenol-urethane-based composite foam. With respect to this composite foam, the density (surface layer portion and core layer portion), bending strength, and thermal conductivity were measured by the above-described test method. Table 1 shows the results. In the measurement of the bending strength, the test piece does not break immediately after the yield point breakage but shows a different fracture behavior such as gradually decreasing strength.
It was tougher than the composite foam containing no glass fiber. In addition, this composite foam did not contain voids, and had excellent self-extinguishing properties and good heat resistance.

[0027]

(Comparative Example 1) In Example 1, except that a curable resin composition having the composition ratio shown in Table 1 and containing no foaming agent and no foam stabilizer was used and the molding temperature was set to 50 ° C. In the same manner as in Example 1, production of a phenol urethane molded body containing expanded particles and measurement of physical properties were performed. Table 1 shows the measurement results. Also, this composite foam,
It had excellent self-extinguishing properties and good heat resistance.

Comparative Example 2 Each component was charged into a homogenizer manufactured by Tokushu Kika Kogyo Co., Ltd. at the ratio shown in Table 1, and the mixture was added at room temperature.
The foamable composition was prepared by mixing for 0 seconds. Next, the foamable composition in an amount corresponding to a pack ratio of 120% was placed in a mold (2).
(5 × 25 × 25 cm), and the upper mold was clamped and foam-cured in a dryer at a temperature of 50 ° C. to obtain a phenol urethane foam containing no foam particles. With respect to this foam, the density (surface layer portion and core layer portion), flexural strength and thermal conductivity were measured by the above-described test method. Table 1 shows the results. Further, this foam had excellent self-extinguishing properties and good heat resistance, but voids were scattered inside the foam.

As shown in Table 1, the composite foam produced in Example 1 had better flexural strength and lower thermal conductivity than the composite foam produced in Comparative Example 1, so that the cured tissue layer The effect by foaming was confirmed. The composite foam produced in Example 2 has a smaller density difference between the surface layer portion and the core layer portion than the conventional foam containing no foam particles produced in Comparative Example 2, and no voids are observed. From this, it was confirmed that the effect due to the presence of the foamed particles was confirmed, and that it had good bending strength and low thermal conductivity. In addition, it was confirmed that the composite foam in combination with the fiber substrate produced in Example 4 had heat insulation performance and tough mechanical strength that would not hinder practical use.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

As described in detail above, according to the present invention, an industrially useful composite foam having the following effects can be provided.

(1) Since the composite foam of the present invention is composed of foamed particles and a hardened tissue layer having a cellular structure filled so as not to form voids between the foamed particles, the foamed particles and the non-cellular structure A composite foam composed of a hardened tissue layer of
Or, it has improved heat insulating performance and mechanical strength as compared with a conventional foam containing no foam particles, and furthermore, has a strong mechanical strength when used together with a fiber base material.

(2) Since the composite foam of the present invention is produced in a state in which the reaction heat and foaming pressure generated during foam curing and foaming pressure are much milder than the conventional foamable composition containing no foam particles, the density difference (surface layer) (Between the portion and the core layer portion) is small and does not include voids, and has high quality reliability. Moreover, unlike the conventional foam, there is no need to cut and remove the surface layer, and a large amount of waste material is not generated. This not only enables a reduction in cost such as an improvement in product yield and a significant reduction in waste material disposal costs, but also a reduction in waste material. Environmental problems associated with processing can be reduced. Furthermore, commercialization of a large bulky composite foam can be made extremely stable and easy.

Continuation of the front page (56) References JP-A-4-366144 (JP, A) JP-A-64-74236 (JP, A) JP-A-60-125649 (JP, A) JP-A-60-127333 (JP, A) , A) JP-A-63-170435 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 9/00-9/42 C08G 18/00-18/87

Claims (2)

(57) [Claims] 1. A composite foam characterized in that polyvinylidene chloride-based expanded particles are contained in a phenol urethane-based foam structure. 2. The composite foam according to claim 1, wherein a fiber base material is further contained in the phenol urethane foam structure.