JP2002069222A - Foam and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic foam used particularly for a building material, a material for household electrical appliances such as a printer, a sound insulat ing material for automobiles, a material for musical instruments, a sound insulat ing material for a road, or the like, and its manufacturing method. SOLUTION: The plastic foam is produced by subjecting a mixture of two or more resins incompatible with one another and different in solubility in a foaming agent, in a state in which the resins undergo phase separation, to foaming by the foaming agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for foams made of plastic, particularly for construction materials, components of home electric appliances such as printer housings, sound insulation materials of automobiles, components of musical instruments, and sound insulation panels of roads. The present invention relates to a foam and a method for producing the same.

[0002]

2. Description of the Related Art Foams made of plastic are lightweight and have heat insulation, sound insulation and sound absorption properties, and are therefore used for building materials, components of musical instruments, sound insulation panels for roads and the like. In general, sound insulation and sound absorption improve as the continuity of the bubbles formed in the foam increases, but the heat insulation and water resistance decrease. As a method for achieving both excellent sound insulation, sound absorption, heat insulation, and water resistance, for example, a method of introducing particles that resonate with a sound wave and absorb into voids (voids) such as bubbles in a foam. However, there are problems such as complicated steps, high cost, and difficulty in continuous processing. Therefore, with a simple structure, a foam which is excellent in all of sound insulation, sound absorption, and heat insulation and easy to produce has not been obtained.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a foam excellent in heat insulation, sound insulation and sound absorption.

[0004]

The present invention has the following arrangement. (1) A foam obtained by foaming a resin mixture in which two or more resin compositions which are incompatible with each other and have different solubilities in a foaming agent in a phase-separated state are foamed by the foaming agent. . (2) The foam according to (1), wherein at least one of the resin compositions is present in a non-foamed state. (3) foaming a resin mixture in which, among two or more resin compositions incompatible with each other, a resin composition having the highest solubility in a foaming agent and another resin composition mixed in a dispersed state; The foam according to (1) or (2), which is formed by foaming with an agent. (4) A resin mixture in which fine particles comprising at least one resin composition among two or more resin compositions incompatible with each other are mixed in a state of being dispersed in another resin composition. The foam according to any one of (1) to (3), wherein the foam is formed by foaming. (5) The foam according to (4), wherein the resin composition constituting the fine particles is a resin composition that does not foam when a foam is formed. (6) It is composed of two types of resin compositions which are incompatible with each other and have different solubilities with respect to a foaming agent (1).
The foam according to any one of (1) to (5). (7) The solubility S1 of the resin composition in the blowing agent at the same temperature and the same pressure [g-gas /
g-polymer] and S2 [g-gas / gp]
polymer] (g-gas: weight of blowing agent, g-po
lymer: the weight of the resin composition, S1 <S2) is 0.
The foam according to (6), wherein 01 ≦ [S1 / S2] ≦ 0.7. (8) The foam according to (7), wherein the volume ratio of the resin composition having the lower solubility to the foaming agent is 0.1 to 50% before foaming. (9) The foam constituting the foam has a bell-shaped structure in which the unfoamed particles are included, and a part or all of the outer surface of the unfoamed particles is released from the inner wall surface of the bubble and can move independently of the inner wall surface of the bubble. The foam according to any one of (1) to (8), wherein: (10) The volume ratio of the unexpanded particles to the total volume of the cells is 0.1 to 99% (9).
The foam as described. (11) Mixing and dissolving a foaming agent under pressure in a resin mixture in which two or more resin compositions incompatible with each other are mixed in a phase-separated state, then depressurizing or depressurizing, and then heating. The method for producing a foam according to any one of (1) to (10), wherein the foaming agent is vaporized and foamed. (12) A foaming agent is mixed and dissolved in a resin mixture in which two or more resin compositions incompatible with each other are mixed in a phase-separated state under a high-temperature pressurized state, and then depressurized or depressurized to thereby form a foaming agent. The method for producing a foam according to any one of (1) to (10), wherein (13) The method for producing a foam according to (11) or (12), wherein the foaming agent is mixed and dissolved in a supercritical state. (14) A foaming agent is mixed and dissolved in a molded article obtained by molding a resin mixture in which two or more resin compositions incompatible with each other are mixed in a phase separated state. (13) The method for producing a foam according to any one of (13). (15) A desired shape can be obtained by molding a resin mixture in which two or more resin compositions incompatible with each other are mixed in a phase-separated state into a smaller size than a desired shape. (14) The method for producing a foam according to (14), wherein the foaming agent is mixed and dissolved in the molded body after being housed in a mold. (16) A foaming agent is mixed and dissolved in a resin mixture in which two or more types of resin compositions incompatible with each other are mixed in a phase-separated state, and the resin mixture is formed into a mold capable of exhibiting a desired shape. (11) to (1) characterized by being housed and foamed
The method for producing a foam according to any one of 3).

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The foam of the present invention is formed by foaming a resin mixture in which two or more resin compositions which are incompatible with each other and have different solubilities with respect to a foaming agent are mixed in a phase-separated state. Is done. Each composition of the resin composition,
Incompatible with each other, can be mixed in a phase-separated state, is not particularly limited as long as a desired foamed state can appear with a different solubility in a foaming agent as described below, for example, polyethylene, polypropylene, Olefin resins such as ethylene-propylene resin and ethylene-ethylene acrylate resin, polystyrene, butadiene-styrene copolymer, acrylonitrile-styrene copolymer (AS), acrylonitrile-butadiene-styrene copolymer (AB
Styrene resins such as S), cyclic polyolefin resins,
Polyacetal resin such as polyvinyl chloride, polyvinylidene chloride, polybutene, polycarbonate resin, polyoxymethylene resin, polyphenylene oxide, polyvinyl alcohol, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, saturated polyester resin such as polyethylene naphthalate, Non-crystalline polyester resin, biodegradable polyester resin (for example, polycarboxylic acid condensate such as polycaprolactone and polylactic acid, and diol and dicarboxylic acid condensate such as polybutylene succinate), cellulose such as triacetate and diacetate Resin, 6-nylon, 6-
Polyamide resin such as 6-nylon and 12-nylon, polyimide resin, fluorine resin, polysulfone, polyethersulfone, polyarylate, polyetherketone, liquid crystal polymer, ethylene-vinyl acetate copolymer, polyphenylene sulfide, polyetherimide , Polyetheretherketone, and the like. 2 above
The at least one kind of resin composition may be any one of the above-mentioned resins or a mixture of two or more kinds thereof as long as they are incompatible with each other.

The above two or more resin compositions have different solubilities with respect to a foaming agent used in forming a foam. Due to the difference in solubility in the blowing agent,
The desired properties can be satisfied by different types of resin compositions having different foaming states and exhibiting a unique cell structure. Specifically, due to the different solubility in the foaming agent, during foaming, the resin composition having a large solubility in the foaming agent foams in the same manner as a single polymer, while the resin composition having a large solubility in the foaming agent makes the foaming agent more foamable. Since the resin composition absorbs a large amount, the resin composition having a low solubility in the foaming agent has a smaller degree of foaming than the resin composition having a high solubility in the foaming agent, or remains in a state before foaming. When the degree of foaming is greatly different, the foaming of the resin composition having a high solubility in the foaming agent causes peeling at the interface between the resin compositions, and as described later, is constituted by the resin composition having a high solubility in the foaming agent. A structure in which unexpanded particles are included in bubbles, that is, a bell-shaped structure can be formed.

[0007] When the two or more resin compositions are two kinds of resin compositions, their solubility S1 [g-gas / g in a foaming agent at the same temperature and under the same pressure.
-Polymer] and S2 [g-gas / g-po]
lymer] (g-gas: weight of blowing agent, g-pol
ymer: weight of the resin composition, S1 <S2) is 0.0
It is preferable that 1 ≦ [S1 / S2] ≦ 0.7. When the solubility ratio is within the above range, it becomes easy to obtain a bubble structure suitable for each desired property.

[0008] The solubility of the resin composition in the foaming agent may be, for example, a value measured by the following measuring method. The simplest method is a method in which a resin composition is impregnated with a foaming agent in a pressurized state using an autoclave or the like, and the weight of the resin composition measured immediately after depressurization is compared with the weight before impregnation. Further, a method of measuring a change in weight of the resin composition by attaching a magnetic suspension balance to an autoclave, or a method of detecting a pressure change during pressurization may be used.

The types and mixing ratios of the resin composition and the foaming agent described below are selected so that at least one of the two or more resin compositions is present in a state in which it does not foam even after the foam is formed. Good to do. Desired characteristics can be satisfied by at least one of the above two or more resin compositions being present in a non-foamed state even after the foam is formed.

The method for selecting the type of the resin composition is, for example, a method for selecting from the empirical foaming state of the foaming agent for each resin composition, and a method for selecting the foaming agent from carbon dioxide gas. A method using a dipole moment as an index as disclosed in Kaihei 10-036547 can be used. In the selection of the resin composition and the foaming agent, since the resin composition is in a foamed state when a foam is formed, the foaming agent is absorbed in the case of a volatile foaming agent (in the case of a volatile foaming agent). With softening sufficiently under the temperature conditions of foaming,
In addition, it is necessary that the foaming agent or gas generated from the foaming agent during foaming does not simply evaporate and diffuse from the resin composition, but vaporizes in the resin and expands the resin.

The mixing ratio of each resin composition in the above resin mixture is not particularly limited, and is appropriately set according to the desired properties of the foam (for example, lightness). When two types of resin compositions are mixed, the volume ratio of the resin composition having the lower solubility to the foaming agent to the whole resin mixture is preferably 0.1 to 50%, more preferably 5 to 50% before foaming. It is preferable to set it to 30%. By setting the volume ratio of the resin composition having the smaller solubility to the foaming agent in the above range, a structure in which the unfoamed particles are included in the bubbles, that is, a bell-shaped structure can be formed as described later.

The type of the foaming agent used in the present invention is not particularly limited as long as at least one of the above resin compositions can be foamed, and can be selected depending on the type of the resin composition to be used, the desired cell shape, and the like. Conventionally known ones can be used. As a foaming agent, for example, low-molecular-weight olefin-based foaming agents such as propane and butane, chlorofluorocarbon-based foaming agents such as HFC134a, carbon dioxide gas, and inorganic volatile foaming agents such as nitrogen gas;
Decomposable foaming agents such as alkali metal carbonates such as ammonium carbonate and sodium carbonate, alkali metal bicarbonates such as ammonium bicarbonate and sodium bicarbonate, azo compounds, sulfonyl hydrazide compounds, semicarbazide compounds, nitroso compounds and azide compounds. No.

The low-molecular-weight olefin-based blowing agent is suitable especially when the resin composition to be foamed is a polyolefin-based resin or polystyrene. When a low molecular weight olefin-based blowing agent is used, a post-treatment such as exchange of gas components with air is performed after the foaming of the resin mixture. The CFC-based foaming agent is excellent in flame retardancy and heat insulating property retention of the foam due to CFCs enclosed in the cells, and is particularly suitable when the resin composition to be foamed is polystyrene.

The foam of the present invention may contain a foam nucleating agent for promoting foaming. In addition, the foam nucleating agent needs to be added to the resin composition which is in a foamed state when the foam is formed. Preferably, the resin composition is melt-kneaded in advance into a foamed resin composition when the foam is formed. Examples of the foam nucleating agent include inorganic powders such as talc, calcium carbonate, clay, magnesium oxide, zinc oxide, glass, beads, glass powder, titanium oxide, carbon black, and anhydrous silica.

The foam of the present invention may contain, in addition to the above foaming agent, a foam stabilizer such as an organosiloxane or a fluoroalkane ester of an aliphatic carboxylic acid for controlling the diameter of cells before foaming. . These foam stabilizers, like the foam nucleating agent, need to be blended with a resin composition that is in a foamed state when forming a foam, and is preferably a resin composition that is in a foamed state when forming a foam. It is good to be melt-kneaded in advance.

[0016] The foam of the present invention further comprises, in addition to the above components,
Other components such as additives may be contained as long as the effects of the present invention are not impaired.

Further, in the foam of the present invention, the cells constituting the foam contain unexpanded particles, and a part or all of the outer surface of the unexpanded particles is separated from the inner wall of the cell, and the inner wall of the cell is separated from the inner wall of the cell. Preferably, it has a bell-shaped structure that can move independently. The bell-shaped structure is formed by exfoliation at the interface between the resin composition foamed by the foaming agent and the resin composition not foamed, and voids are formed between the inner wall surface of the cells and the surface of the unexpanded particles. The void allows the unexpanded particles to move independently of the inner wall surface of the cell.
Interfacial peeling as described above is more likely to occur because the lower the compatibility between the resin compositions, the greater the interfacial tension. Further, the smaller the solubility of the resin composition to be the unfoamed particles in the foaming agent, the larger the porosity inside the cells. The porosity also depends on the expansion ratio of the foamed resin composition, and generally, the higher the expansion ratio, the higher the porosity. In the foam of the present invention, it is preferable that the volume ratio of the unfoamed particles to the whole cells is 0.1 to 99.9%.

As described above, when the cells constituting the foam have a bell-shaped structure, the diameter of the unexpanded particles is not particularly limited, and can be set according to the desired physical properties of the foam. Since the diameter of the unexpanded particles in the resin mixture before foaming is almost the same as the state of the resin composition that becomes the unexpanded particles, the diameter of the unexpanded particles is the resin that becomes the unexpanded particles in the resin mixture. It can be prepared by controlling the size of the domain of the composition. The method of controlling the size of the domain of the resin composition to be unexpanded particles in the resin mixture includes a method of applying a shearing force to the resin composition to be expanded in the resin mixture in a molten state, and a method of applying each resin composition. And the method of adjusting the compounding ratio of the resin composition. Note that, when the cells constituting the foam have a bell-shaped structure, the dispersion state of the cells is also affected by the state of the resin composition to be unexpanded particles. The method of controlling the size of the domain, such as adjusting the molding conditions, can also adjust the dispersed state of the bubbles.

In the foam of the present invention, the diameter of the cells and the volume ratio of the cells to the total volume of the cells are not particularly limited.

In the method for producing a foam of the present invention, a resin mixture is prepared by mixing two or more resin compositions that are incompatible with each other so as to be in a phase-separated state, and the resin mixture is foamed with a foaming agent. If so, there is no particular limitation.

The dispersion state of the mutually incompatible resin composition in the resin mixture before foaming is not particularly limited, but the resin having the highest solubility in the foaming agent among the two or more kinds of mutually incompatible resin compositions. It is preferable that another resin composition is mixed and dispersed in the composition. The resin composition having the highest solubility in the foaming agent is used as a matrix, and the other resin composition is mixed in a dispersed state in the resin composition, whereby foaming of the matrix with the other resin composition is achieved. The state is different, and the interface between the resin compositions is separated. Further, it is preferable that the fine particles comprising at least one resin composition are in a state of being dispersed in another resin composition. When the fine particles are made of a resin composition that does not foam even after forming a foam, that is, a resin composition having a low solubility in a foaming agent, only the resin composition that is a base around the fine particles during foaming foams, To form a bell-shaped structure in which unexpanded particles are enclosed.

In the case where the fine particles comprising at least one resin composition are dispersed in another resin composition in the resin mixture, the diameter and the dispersion state of the fine particles are not particularly limited, and the desired foaming can be achieved. It can be appropriately set according to the characteristics of the body, the state of the cells correlated therewith, the size of the unfoamed particles and the like. The method for dispersing the fine particles in the other resin composition serving as a base is not particularly limited, and the resin composition for forming the fine particles in the resin composition serving as the base is melt-kneaded, and is solidified into fine particles. A method of dispersing is exemplified.

When a volatile foaming agent is used, the mixing of the resin mixture and the foaming agent is preferably carried out under a pressurized condition, more preferably under a pressurized condition at a supercritical temperature or higher within a range not impairing the action of the present invention. Good to do. When using a volatile foaming agent, the foaming conditions are not particularly limited, and after the resin mixture obtained by mixing the foaming agent in a pressurized state is depressurized or decompressed, the foaming agent is heated to the appropriate temperature to thereby reduce the foaming agent. The resin composition in the resin mixture can be foamed by vaporization (physical foaming). Further, it is preferable that the pressure reduction or pressure reduction for foaming be performed in a short time as much as possible. In the case of a decomposable foaming agent, foaming is possible under conditions such as a temperature at which the foaming agent is decomposed to generate gas (chemical foaming).

When a volatile foaming agent is used, it is preferable that the foaming agent be in a supercritical state when the resin mixture and the foaming agent are mixed. By setting the blowing agent in a supercritical state, the diffusion of the blowing agent into the resin mixture is facilitated, and as a result, the amount of the blowing agent mixed is increased. Note that the supercritical state is a state in which, in the case of carbon dioxide gas, the temperature exceeds all the conditions of 31 ° C. and 72.8 atm.

The method of mixing the resin mixture and the foaming agent and the method of foaming are not particularly limited, and examples thereof include the following. One method is to impregnate a molded product obtained by molding a resin mixture in which two or more resin compositions incompatible with each other are mixed in a phase-separated state with a foaming agent (volatile foaming agent). This is a method of mixing and dissolving, and then foaming under appropriate foaming conditions such as pressure and temperature according to the type of foaming agent.
When a decomposable foaming agent is used, a foam can be produced by mixing a decomposable foaming agent in a molded body in advance and performing heating or the like.

As a method for molding a molded article which has been molded before foaming, an ordinary molding method such as an extrusion method or an injection method can be used according to a desired shape.

In the case where a foaming agent is mixed and dissolved in a preformed article as described above and foamed, the foaming agent may be simply foamed after mixing and dissolving the foaming agent in the molded article. In order to obtain a molded product obtained by molding a resin mixture in which two or more types of resin compositions incompatible with each other are mixed in a phase-separated state to a size smaller than a desired shape, a desired shape is formed. It is preferable to mix and dissolve a foaming agent (volatile foaming agent) in the molded article after storing it in a mold that can be exposed, and then foam the molded article. Specifically, a foaming agent injection / removal port is provided in the mold, and after the molded body is accommodated in the mold, the foaming agent is injected under pressure to mix and dissolve the foaming agent into the molded body. Then, by removing the foaming agent, the inside of the mold is depressurized, and foaming of the resin composition occurs, whereby a foam having the same shape as the mold is obtained. When a decomposable foaming agent is used, the decomposable foaming agent is mixed in the molded body in advance, and after the molded body is housed in a mold, heating and the like are performed to form the same shape as the mold. A foam can be manufactured.

As another method, a foaming agent (volatile) is added to a resin mixture in which two or more resin compositions incompatible with each other are mixed in a phase-separated state in the same manner as in a usual foam injection molding method. Foaming agent) is mixed and dissolved to form a molten state, and the resin mixture is housed in a mold capable of producing a desired shape,
There is also an injection molding method for foaming. When a decomposable foaming agent is used, the resin mixture in which the decomposable foaming agent is mixed in advance is housed in a mold that can similarly exhibit a desired shape, and is melted and foamed to obtain a foam. . In the case of such a manufacturing method, after firing in a molten state,
In the process of cooling and solidifying, it is necessary that the resin compositions do not dissolve each other.

The above-mentioned molding can be carried out by using a generally used extrusion molding apparatus, injection molding apparatus, press molding apparatus and the like. In particular, in order to keep the diameter of the bubbles within the above-described preferable range, Japanese Patent Application Laid-Open No. H8-8512.
9, JP-A-10-024436, JP-A-10-2305
28, using a foam injection molding apparatus.

In any of the above methods, the conditions for mixing and dissolving the foaming agent, such as temperature and pressure, and the foaming conditions are appropriately set according to the type and composition of the resin composition and the foaming agent to be used and the state of the desired foam. You.

In the case of a method in which a foaming agent is mixed and dissolved in a resin mixture and the resin mixture is housed in a mold and foamed, the temperature of the foaming agent mixed and dissolved and the foaming temperature, that is, the temperature of the mold, is: The temperature is preferably equal to or lower than the glass transition temperature of the resin composition which does not expand into particles.

The foam of the present invention is suitable for building materials, components of home electric appliances such as printer housings, sound insulating materials of automobiles, components of musical instruments, sound insulating panels of roads and the like.

[0033]

EXAMPLE 1 A blend of polybutylene terephthalate (PBT) particles dispersed in acrylonitrile-butadiene-styrene copolymer (ABS) (PBT / ABS = 30% by weight /
70% by weight, the PBT particle volume ratio in the blend was 25%, and the blended state is shown in FIG. 1: Novalloy B (manufactured by Daicel Chemical Industries, Ltd.) into a sheet having a thickness of 1 mm by hot pressing and then using an autoclave. 60 ° C, 20M
Carbon dioxide was impregnated with Pa for 1 hour. The weight ratio of the foaming agent to the impregnated sheet was 9.0% by weight. The impregnated sheet was heat-treated in a 70 ° C. warm bath for 1 minute to obtain a foam. The ratio of the solubility of PBT to the solubility of carbon dioxide in ABS is 0.45 (the solubility of PBT / the solubility of ABS), and the expansion ratio of the foam (expansion ratio = resin density / apparent density of the foam) is 2.5. It was twice. When the cell structure of the obtained foam was observed using a scanning electron microscope, as shown in FIG. 2, the PBT particles hardly foamed, and remained as spherical particles having a particle diameter of 2 to 6 μm. A bell-shaped structure around which an ABS foam structure was formed was observed. In the bell-shaped structure, the bubble diameter of the ABS is 2 to 10 μm, and the porosity of the entire bubble is 80 to 10 μm.
95%.

Example 2 30 wt% of polybutylene terephthalate (PBT, manufactured by Polyplastics Co., Ltd., 500 FP) and 70 wt% of polystyrene (PS, manufactured by Toyo Styrol, G340C) were mixed using a 50φ-65φ tandem type foam extruder. Dry blending is performed to prepare a blend in which PBT particles are dispersed in PS (PBT / PS = 30% by weight / 70% by weight, volume ratio of PBT particles in the blend is 25%), and isobutane is mixed and dissolved in the blend. Foaming was performed at 12 ° C. and 12 MPa to obtain a sheet-like foam having a thickness of 5 mm. The weight ratio of blowing agent to blend was 9.0% by weight.
The ratio of the solubility of PBT to the solubility of PS in isobutane is 0.66 (PBT solubility / PS solubility),
The expansion ratio of the foam (expansion ratio = resin density / apparent density of the foam) was 32 times. When the cell structure of the obtained foam was observed using a scanning electron microscope, it was found that PBT
The particles hardly foamed and remained spherical with a particle diameter of 3 to 10 μm, and a bell-shaped structure in which a foamed structure of PS was formed around the particles was observed. Note that PS in the bell-shaped structure
Was 50 to 80 μm, and the porosity of all the bubbles was 95 to 99%. FIG. 3 shows the transmission loss for each frequency as the sound insulation characteristic of the foam.

Comparative Example 1 A blend of polycarbonate resin (PC) particles dispersed in an acrylonitrile-butadiene-styrene copolymer (ABS) (PC / ABS = 70% by weight / 30% by weight, volume ratio of PC particles in the blend: 34) %: Novalloy S,
1m by hot press
After forming into a sheet having a thickness of m, carbon dioxide gas was impregnated at 60 ° C. and 20 MPa for 1 hour using an autoclave. The weight ratio of the foaming agent to the impregnated sheet is 7.0% by weight.
Met. The impregnated sheet was heat-treated in a 70 ° C. warm bath for 1 minute to obtain a foam. The ratio of the solubility of PC to the solubility of ABS in carbon dioxide is 0.76 (P
C / solubility of ABS), and the expansion ratio of the foam (expansion ratio = resin density / apparent density of the foam) is 1.
It was eight times. When the cell structure of the obtained foam was observed using a scanning electron microscope, both PC and ABS were foamed, and no bell-shaped structure was observed. The cell diameter of the foam was 2 to 8 μm.

Comparative Example 2 Polystyrene (PS, manufactured by Toyo Styrol, G340C)
100% by weight of isobutane was mixed and dissolved using a 50φ-65φ tandem type foam extruder, and the mixture was mixed at 95 ° C and 7.5MPa.
A foam molding was performed in a to obtain a sheet-like foam having a thickness of 5 mm. The weight ratio of blowing agent to blend was 10.0% by weight. Expansion ratio of foam (expansion ratio = resin density /
The apparent density of the foam was 35 times. The cell diameter of the obtained foam was 150 to 180 μm. FIG.
The transmission loss for each frequency is shown as the sound insulation property of the foam.

[0037]

The foam of the present invention is excellent in heat insulation, sound insulation and sound absorption. Further, it is easy to manufacture, particularly continuous manufacturing is possible, and is excellent in cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a dispersion state of a resin composition in a resin mixture in which PBT is mixed in ABS in a phase-separated state.

FIG. 2 is a view showing a state where the resin mixture of FIG. 1 is foamed.

FIG. 3 is a view showing a difference in sound insulation characteristics between the foam of Example 2 and the foam of Comparative Example 2.

[Explanation of symbols]

 1 Base (ABS resin) 2 Fine particles (PBT resin) 3 Unexpanded particles 4 Bubbles

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 4F074 AA15 AA56 AA97 AA98 AB00 BA03 BA04 BA06 BA13 BA14 BA15 BA16 BA17 BA18 BA32 BA33 BA36 BA37 BA53 CA22 CA26 CC22X DA32 DA57

Claims (16)

[Claims] 1. A resin mixture in which two or more resin compositions which are incompatible with each other and have different solubilities in a foaming agent are mixed in a phase-separated state, and are foamed by the foaming agent. Foam. 2. The method according to claim 1, wherein at least one of the resin compositions is present in a non-foamed state.
The foam as described. 3. A resin mixture in which, among two or more resin compositions incompatible with each other, a resin composition having the highest solubility in a foaming agent is mixed with another resin composition in a dispersed state. The foam according to claim 1, wherein the foam is foamed with the foaming agent. 4. A resin mixture in which fine particles composed of at least one resin composition are mixed in a state of being dispersed in another resin composition among two or more resin compositions incompatible with each other. The foam according to any one of claims 1 to 3, wherein the foam is foamed with a foaming agent. 5. The foam according to claim 4, wherein the resin composition constituting the fine particles is a resin composition which is present in a non-foamed state when the foam is formed. 6. The foam according to claim 1, comprising two types of resin compositions which are incompatible with each other and have different solubilities in a foaming agent. 7. The solubility S1 [g- of the resin composition in the foaming agent at the same temperature and under the same pressure.
gas / g-polymer] and S2 [g-gas
/ G-polymer] (g-gas: weight of blowing agent,
g-polymer: weight of the resin composition, S1 <S2)
7. The foam according to claim 6, wherein satisfies 0.01 ≦ [S1 / S2] ≦ 0.7. 8. The foam according to claim 7, wherein the volume ratio of the resin composition having the lower solubility to the foaming agent is 0.1 to 50% before foaming. 9. A bell-like shape in which the cells constituting the foam contain unexpanded particles, and a part or all of the outer surface of the unexpanded particles is free from the inner wall surface of the cell and can move independently of the inner wall surface of the cell. The foam according to any one of claims 1 to 8, wherein the foam has a structure. 10. The foam according to claim 9, wherein the volume ratio of the unexpanded particles to the total volume of the cells is 0.1 to 99.9%. 11. A foaming agent is mixed and dissolved in a resin mixture in which two or more resin compositions incompatible with each other in a phase-separated state, and then depressurized or depressurized, and then heated. The method for producing a foam according to any one of claims 1 to 10, wherein the foaming agent is vaporized and foamed. 12. A foaming agent is mixed and dissolved in a resin mixture in which two or more resin compositions incompatible with each other are mixed in a phase-separated state under a high-temperature pressurized state, and then depressurized or reduced in pressure. The method for producing a foam according to any one of claims 1 to 10, wherein the foaming agent is vaporized and foamed. 13. The method for producing a foam according to claim 11, wherein the foaming agent is mixed and dissolved in a supercritical state. 14. A foaming agent is mixed and dissolved in a molded product obtained by molding a resin mixture in which two or more resin compositions incompatible with each other are mixed in a phase-separated state. A method for producing a foam according to any one of items 11 to 13. 15. A molded product obtained by molding a resin mixture in which two or more resin compositions incompatible with each other are mixed in a phase-separated state to a size smaller than a desired shape, to obtain a desired shape. The method for producing a foam according to claim 14, wherein the foaming agent is mixed and dissolved in the molded body after being housed in a mold capable of being taken out. 16. A metal that can form a desired shape by mixing and dissolving a foaming agent in a resin mixture in which two or more resin compositions incompatible with each other are mixed in a phase-separated state. The foam is accommodated in a mold and is foamed.
14. The method for producing a foam according to any one of claims 13 to 13.