Master batch, method for manufacturing master batch, and method for molding foam resin composition

Abstract

To provide a master batch which can foam a high viscosity resin, without requiring a special facility.SOLUTION: A master batch contains a base material resin having a melt flow rate of 5 g / 10 min or more, a chemical foaming agent, and at last one of hollow glass and hollow silica. For example, 1 to 50 pts.mass of the chemical foaming agent, and 1 to 50 pts.mass of at least one of the hollow glass and the hollow silica are contained with respect to 100 pts.mass of the base material resin.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a masterbatch, a method for producing a masterbatch, and a method for molding a foamed resin composition. [Background technology]

[0002] In recent years, the use of resin parts has become widespread in fields such as electronics, machinery, and automobiles. In addition, foaming technology is being used in these resin parts to further reduce their weight and dielectric constant. In low-viscosity resins, it is relatively easy to control the formation and growth of bubbles. On the other hand, in high-viscosity resins, bubbles are less likely to form during molding due to the high viscosity of the resin. For this reason, foaming high-viscosity resins has been more difficult than low-viscosity resins.

[0003] A technique for foam molding of high-viscosity resin is disclosed in, for example, Patent Document 1. In the technique of Patent Document 1, a molding resin in which a supercritical fluid is impregnated is used. Then, this molding resin is injected into a mold. During this molding, foaming occurs. For example, carbon dioxide or nitrogen is used as the supercritical fluid. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-024689 A Summary of the Invention [Problem to be solved by the invention]

[0005] A supercritical fluid is used in the technology of the above-mentioned Patent Document 1. In order to impregnate a resin with such a supercritical fluid, special equipment for confining the high-pressure supercritical fluid is required.

[0006] The present disclosure has been made in consideration of the above problems, and aims to provide a masterbatch or the like that is capable of foaming a high-viscosity resin without requiring special equipment. [Means for solving the problem]

[0007] In order to solve the above problems, the masterbatch of the present disclosure includes a base resin having a melt flow rate of 5 g / 10 min or more, a chemical foaming agent, and at least one of hollow glass and hollow silica.

[0008] In addition, the method for producing a masterbatch of the present disclosure includes melting a base resin having a melt flow rate of 5 g / 10 min or more, adding a chemical foaming agent to the molten base resin, adding at least one of hollow glass or hollow silica to the molten base resin, and kneading the base resin, the chemical foaming agent, and the at least one of hollow glass or hollow silica.

[0009] In addition, the molding method of the foamed resin composition of the present disclosure includes mixing the above-mentioned master batch and pellets of a base resin that serves as a base for molding, dry stirring the mixture, controlling the temperature of the dry-stirred mixture of the master batch and the base resin to a temperature at which the chemical foaming agent foams, and performing molding. Effect of the Invention

[0010] The effect of the present invention is to provide a masterbatch or the like capable of foaming a high-viscosity resin without requiring any special equipment. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing an example of a masterbatch according to the present disclosure. [Diagram 2] 1 is a flow chart illustrating an example of a method for producing a masterbatch according to the present disclosure. [Diagram 3] 1 is a flowchart showing an example of a method for molding a foamed resin composition of the present disclosure. [Figure 4] 1 is a schematic cross-sectional view showing an example of a foamed resin composition according to the present disclosure. FIG. [Diagram 5] 1 is a cross-sectional observation photograph showing an example of a foamed resin composition according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. However, the embodiments described below are limited in a technically preferable manner for carrying out the present disclosure, but the scope of the invention is not limited to the following. Note that the same reference numbers are used for similar components in each drawing, and descriptions thereof may be omitted.

[0013] (First embodiment) Fig. 1 is a schematic diagram showing an example of a master batch 10 of the present disclosure. The master batch 10 includes a base resin 1, a chemical foaming agent 2, and at least one of hollow glass or hollow silica 3. Note that the chemical foaming agent 2 and hollow glass or hollow silica 3 depicted in Fig. 1 are merely schematic. In other words, their sizes and shapes are not limited to those shown in the example of Fig. 1.

[0014] The base resin 1 is a resin with a melt flow rate of 5g / 10min or more. Here, the melt flow rate is an index showing the fluidity of molten plastic. The melt flow rate is measured by a method specified in JIS_K7210. In this measurement, the resin is placed in a cylindrical extrusion type plastometer. Next, the resin is heated and pressurized at a constant temperature. Then, the amount of resin extruded from the opening at the bottom of the container in 10 minutes is measured. This amount of resin is the melt flow rate. In general, the higher the melt flow rate, the lower the viscosity of the resin when melted. Conversely, the lower the melt flow rate, the higher the viscosity of the resin when melted. In the following explanation, a resin with a high melt flow rate when melted is called a low viscosity resin. Also, a resin with a low melt flow rate when melted is called a high viscosity resin. The boundary value is 5g / 10min.

[0015] Specifically, the base resin 1 is, for example, a polystyrene-based resin. The base resin 1 may also be any of polylactic acid-based resin, AS-based resin, ABS-based resin, polypropylene-based resin, and polyamide-based resin. Here, AS is an abbreviation for Acrylonitrile_Styrene. Also, ABS is an abbreviation for Acrylonitrile-butadiene-styrene.

[0016] Various common chemical foaming agents 2 can be used as the chemical foaming agent 2. For example, chemical foaming agents such as sodium bicarbonate, ADCA, and nitrogen are used. Note that ADCA is an abbreviation for Azodicarbonamide.

[0017] The hollow glass or hollow silica 3 is a hollow body having an average particle size of, for example, 0.5 to 200 μm. The difference between hollow glass and hollow silica is the material of the solid portion. The density of hollow glass or hollow silica 3 in a vacuum is, for example, 0.1 to 0.8 g / cm3. In this way, the hollow glass or hollow silica 3 is a hollow body containing air. For this reason, mixing hollow glass or hollow silica 3 makes it possible to reduce the weight and the dielectric constant of the resin.

[0018] The master batch 10 is formed, for example, into a pellet shape. Fig. 2 is a flow chart showing an example of a method for producing the master batch 10 of the present disclosure.

[0019] In the method for producing the master batch 10, a base resin 1 having a melt flow rate of 5 g / 10 min or more, a chemical foaming agent 2, and hollow glass or hollow silica 3 are kneaded together. Specifically, the base resin 1 is first melted (S101). Next, the chemical foaming agent 2 is added to the molten base resin 1 (S102). Also, at least one of hollow glass or hollow silica 3 is added to the molten base resin 1 (S103). The order of S102 and S103 may be reversed. Then, the base resin 1, the chemical foaming agent 2, and at least one of hollow glass or hollow silica 3 are kneaded together (S104). Next, the kneaded resin composition is solidified (S105). At this time, for example, the resin composition is formed into a pellet shape. In this way, the master batch 10 is completed.

[0020] In the present disclosure, the base resin 1 is a low-viscosity resin with a melt flow rate of 5 g / 10 min or more. Therefore, even if the hollow glass or hollow silica 3 is kneaded with the base resin 1, the hollow glass or hollow silica 3 is unlikely to be broken. In contrast, if the base resin 1 is a high-viscosity resin, the hollow glass or hollow silica 3 will be broken during kneading. For these reasons, a low-viscosity resin is used as the base resin 1.

[0021] For example, 1 to 50 parts by mass of chemical foaming agent 2 is mixed with 100 parts by mass of base resin 1. If the amount of chemical foaming agent 2 is less than 1 part by mass, sufficient foaming cannot be obtained. If the amount of chemical foaming agent 2 is 50 parts by mass or more, it becomes difficult to solidify base resin 1. Similarly, 1 to 50 parts by mass of hollow glass or hollow silica 3 is mixed with 100 parts by mass of base resin 1. If the amount of hollow glass or hollow silica 3 is less than 1 part by mass, sufficient voids cannot be obtained. If the amount of hollow glass or hollow silica 3 is 50 parts by mass or more, it becomes difficult to solidify base resin 1.

[0022] The master batch 10 obtained as described above is used, for example, in foam molding using a high-viscosity resin as the base resin. Here, the high-viscosity resin is, for example, a resin having a melt flow rate of less than 5 g / 10 min. Specifically, for example, the base resin is a modified polyphenylene ether resin. Also, for example, the base resin is a polycarbonate resin. Also, for example, the base resin may be a polyacetal resin or a PBT resin. Here, PBT is an abbreviation for Poly_Butylene_Terephtalate. Also, the base resin may contain a plasticizer. And, for example, the plasticizer contains at least one of a phosphoric acid ester, a trimellitic acid ester, and a pyromellitic acid ester.

[0023] FIG. 3 is a flow chart showing an example of a molding method for a foamed resin composition 100 of the present disclosure. FIG. 4 is a schematic cross-sectional view showing an example of the foamed resin composition 100 of the present disclosure. In the production of the foamed resin composition 100, first, a master batch 10 and a base resin are mixed. Here, for example, a pellet-shaped base resin and a pellet-shaped master batch 10 are mixed. Then, the mixture is dry-mixed (S201). In this example, the hollow glass or hollow silica 3 is pelletized by the base resin 1. That is, the hollow glass or hollow silica 3 is protected by the base resin 1. Therefore, the hollow glass or hollow silica 3 is not destroyed during dry mixing.

[0024] Here, for example, 20 to 100 parts by mass of the master batch 10 is mixed with 100 parts by mass of the base resin. If the amount of the master batch 10 is less than 20 parts by mass, sufficient foaming cannot be obtained. If the amount of the master batch 10 is 100 parts by mass or more, the properties of the base resin are impaired.

[0025] In the dry mixing, for example, the rotation of the mixing blade and the supply of air are utilized. By adopting such a method, the master batch 10 is mixed into the base resin so as to be uniformly distributed.

[0026] Next, the temperature of the mixture after the dry mixing is controlled to a temperature at which the chemical foaming agent 2 foams (S202). In general, the temperature is controlled to a high temperature. This causes the base resin and the master batch 10 to melt. This process is carried out, for example, in a molding machine. In this way, the foamed resin composition 100 is produced.

[0027] Next, the molten foamable resin composition 100 is molded (S203). Typical molding methods are injection molding and extrusion molding, but molding may be performed by other molding methods.

[0028] In the above-mentioned molding method of the foamed resin composition 100, the hollow glass or hollow silica 3 is protected by the base resin 1 in the master batch 10. Then, the master batch 10 is mixed into the base resin by dry stirring. Therefore, the hollow glass or hollow silica 3 is not destroyed in the mixing stage. As a result, sufficient foaming is performed in the molten foamed resin composition 100.

[0029] In the foamed resin composition 100 molded by the above molding method, for example, the foamed resin composition 100 has few voids 4 near the surface and many voids 4 inside.

[0030] 4 is a cross-sectional schematic diagram showing an example of a foamed resin composition 100 of the present disclosure. In this example, the foamed resin composition 100 has a first layer 11, a second layer 12, and a third layer 13. The first layer 11 extends from the surface to a first depth. The second layer 12 extends from the inside of the first layer 11 to a second depth. The third layer 13 extends inside the second layer 12.

[0031] In this example, the second layer 12 contains 0.05 to 20 volume % of hollow glass or hollow silica 3. The third layer 13 contains 0.05 to 20 volume % of hollow glass or hollow silica 3. Furthermore, the third layer 13 contains 5 to 97 volume % of voids 4 having a diameter of 5 to 500 μm.

[0032] (Example) Next, an example of the production of the foamed resin composition 100 will be described. The outline of the foamed resin composition 100 of this example is shown in Example 1 of Table 1. The base resin 1 of the master batch 10 is a polystyrene-based resin. The base resin of the foamed resin composition 100 is a modified polyphenylene ether-based resin.

[0033] In the first step of producing the master batch 10, 10% by mass of hollow glass, 10% by mass of a chemical foaming agent, 5% by mass of a plasticizer, and 75% by mass of a polystyrene resin were dry mixed. The mixture was then kneaded at a resin temperature of 180°C using a twin-screw kneader. The kneaded resin was then molded into pellets. In this way, the master batch 10 was produced.

[0034] Next, in the second step of producing the foamed resin composition 100, 20 mass % of the master batch and 80 mass % of the modified polyphenylene ether resin were dry stirred. Thereafter, the foamed resin composition 100 was molded at a resin temperature of 310°C and a mold temperature of 80°C.

[0035] In the above-mentioned manufacturing method, breakage of the hollow glass is suppressed. Also, the hollow glass and the chemical foaming agent 2 are dispersed almost uniformly in the base resin. Then, a foamed resin composition 100 containing fine bubbles having a diameter of 0.15 mm or less was produced. Also, the relative dielectric constant (40 GHz) of the molded body was 2.3, realizing a low dielectric constant. Also, compared with the resin composition of Comparative Example 4, a weight reduction of 89% was realized.

[0036] The cross section of the test piece was observed under an electron microscope to confirm whether or not the hollow glass was broken.

[0037] The dielectric constant was measured by a radio wave measuring device using the free space method. The hollow glass used was Glass Bubbles, the plasticizer was trimellitic acid ester, and the chemical foaming agent was a sodium bicarbonate-based agent. The polystyrene-based resin was polystyrene. The modified polyphenylene ether-based resin was Zylon (registered trademark).

[0038] [Table 1] The hollow glass or hollow silica 3 may be surface-treated. There are no particular limitations on the surface treatment agent, but preferred examples include silane coupling agents such as silane-based, titanium-based, aluminum-based, and zirconium-based silane coupling agents.

[0039] Fig. 5 is a cross-sectional observation photograph showing an example of the foamed resin composition 100 of the present disclosure. Fig. 5 shows the result of cross-sectional observation (digital microscope 50x) of a molded article of an example. The molded article of Example 1 has a first layer (skin layer) including a thermoplastic resin layer in contact with the mold. In addition, a second resin layer is provided inside the first layer. The second resin layer includes a thermoplastic resin layer in which hollow glass is uniformly dispersed. Furthermore, a foamed layer including bubbles, hollow glass, and thermoplastic resin is formed in contact with the second layer.

[0040] In a general method for producing a foamed resin, it is difficult to foam a thermoplastic resin having a high viscosity. However, according to this embodiment, the production of a foamed resin composition 100 using a thermoplastic resin having a high viscosity as a base resin is easily realized. This is because the master batch 10 contains hollow glass or hollow silica 3. In molding the foamed resin composition 100, the hollow glass or hollow silica 3 acts as a core material. This allows fine bubbles to be developed in a nearly uniform state in the base resin. As a result, the molded product can be made lighter and have a lower dielectric constant.

[0041] The above describes the master batch 10 etc. of the present disclosure.

[0042] A master batch 10 of the present disclosure includes a base resin 1, a chemical foaming agent 2, and at least one of hollow glass and hollow silica 3. The base resin 1 is a resin having a melt flow rate of 5 g / 10 min or more.

[0043] In this configuration, at least one of the chemical foaming agent 2 and the hollow glass or hollow silica 3 is confined in the base resin 1. In other words, a master batch 10 with a built-in foaming function is obtained. In other words, since the hollow glass or hollow silica 3 is protected, it is suitable for foaming high-viscosity resins.

[0044] According to one embodiment, the master batch 10 contains 1 to 50 parts by mass of a chemical foaming agent 2 relative to 100 parts by mass of a base resin 1. Also, the master batch 10 contains 1 to 50 parts by mass of at least one of hollow glass and hollow silica 3 relative to 100 parts by mass of a base resin 1.

[0045] In this configuration, a sufficient foaming function is obtained. Also, the base resin 1 can be solidified. If the amount of the chemical foaming agent 2 is less than 1 part by mass, sufficient foaming is not obtained. Also, if the amount of the chemical foaming agent 2 is 50 parts by mass or more, it becomes difficult to solidify the base resin 1. Similarly, if the amount of the hollow glass or hollow silica 3 is less than 1 part by mass, sufficient voids 4 are not obtained. Also, if the amount of the hollow glass or hollow silica 3 is 50 parts by mass or more, it becomes difficult to solidify the base resin 1.

[0046] According to one embodiment, in the master batch 10, the base resin 1 is a polystyrene-based resin.

[0047] Polystyrene resins have a low viscosity, which means that the hollow glass or hollow silica particles 3 are less likely to be destroyed during kneading. In addition, polystyrene resins are easily available.

[0048] According to one embodiment, in the master batch 10, the base resin 1 is any one of a polylactic acid-based resin, an AS-based resin, an ABS-based resin, a polypropylene-based resin, and a polyamide-based resin.

[0049] These resins also have low viscosity. Therefore, the hollow glass or hollow silica 3 is not easily broken during kneading. In addition, they are easily available.

[0050] According to one embodiment, in the master batch 10, the hollow glass or hollow silica 3 has a density of 0.1 to 0.8 g / cm3.

[0051] The use of such hollow glass or hollow silica 3 imparts to the resin a function of forming sufficient foaming.

[0052] According to one embodiment, the hollow glass or hollow silica 3 in the master batch 10 has an average particle size of 0.5 to 200 μm.

[0053] By using hollow glass or hollow silica 3 having a small average particle size as described above, it becomes possible to form bubbles with excellent uniformity.

[0054] According to one embodiment, the chemical foaming agent 2 in the master batch 10 is at least one of a sodium bicarbonate type, an ADCA type, and a nitrogen type.

[0055] The above-mentioned chemical foaming agent 2 has excellent foaming properties and is easily available.

[0056] In addition, in the method for producing a masterbatch of the present disclosure, a base resin 1, a chemical foaming agent 2, and at least one of hollow glass and hollow silica 3 are kneaded together. Specifically, first, the base resin 1 is melted. Next, the chemical foaming agent 2 is added to the molten base resin 1. Also, at least one of hollow glass and hollow silica 3 is added to the molten base resin 1. Then, the base resin 1, the chemical foaming agent 2, and at least one of hollow glass and hollow silica 3 are kneaded together. Here, the melt flow rate of the base resin 1 is 5 g / 10 min or more.

[0057] As described above, by using a base resin having a large melt flow rate, the hollow glass or hollow silica particles 3 are less likely to be broken during kneading.

[0058] In addition, in the molding method of the foamed resin composition of the present disclosure, the master batch 10 and pellets of the base resin are dry-mixed. Here, the base resin is a resin that serves as a base for molding. Then, the temperature of the dry-mixed mixture of the master batch 10 and the base resin is controlled to a temperature at which the chemical foaming agent 2 foams. This forms a foam with good uniformity in the base resin. Then, molding of this foamed resin is performed.

[0059] In the above method, the master batch 10 is dispersed in the base resin while the hollow glass or hollow silica 3 is embedded in the master batch 10. Therefore, the hollow glass or hollow silica 3 is dispersed in the base resin without being destroyed. As a result, it becomes possible to mold the foamed resin composition 100 with good uniform foaming.

[0060] According to one embodiment, in the method for molding the foamed resin composition 100, molding is performed by injection molding.

[0061] Injection molding allows molding into various shapes, so the foamed resin composition 100 can be molded into various shapes.

[0062] According to one embodiment, in the method for molding the foamed resin composition 100, the molding is performed by extrusion molding.

[0063] Extrusion molding allows molding into various shapes, and therefore the foamed resin composition 100 can be molded into various shapes.

[0064] According to one embodiment, in the method for molding the foamed resin composition 100, 20 to 100 parts by mass of the master batch 10 is mixed with 100 parts by mass of the base resin.

[0065] In this configuration, the properties of the base resin are maintained, and it is possible to mold the foamed resin composition 100 with a sufficient amount of foaming.

[0066] According to one embodiment, in the method for molding the foamed resin composition 100, the base resin is a modified polyphenylene ether resin.

[0067] The modified polyphenylene ether resin has a high viscosity. Therefore, it is difficult to directly foam the resin. However, by using the master batch 10 of the present disclosure, foaming can be easily performed. Then, the foamed resin composition 100 including the foaming can be molded.

[0068] According to one embodiment, in the method for molding the foamed resin composition 100, the base resin is a polycarbonate-based resin.

[0069] Polycarbonate-based resins have high viscosity. For this reason, direct foaming is difficult. However, by using the master batch 10 of the present disclosure, foaming is easily formed. Then, it is possible to mold the foamed resin composition 100 including this foaming. The base resin is According to one embodiment, in the method for molding the foamed resin composition 100, the base resin contains a plasticizer. The plasticizer contains at least one of a phosphoric acid ester, a trimellitic acid ester, and a pyromellitic acid ester.

[0070] These plasticizers are capable of imparting excellent plasticity to the base resin.

[0071] According to one embodiment, in the method for molding the foamed resin composition 100, the dry stirring includes rotating a stirring blade and supplying air.

[0072] In the above-mentioned dry mixing, the master batch 10 is mixed with the base resin with good uniformity. During this mixing, the hollow glass or hollow silica particles 3 are unlikely to be broken.

[0073] The foamed resin composition 100 of the present disclosure includes a base resin and voids 4 formed in the base resin. The foamed resin composition 100 includes a first layer 11, a second layer 12, and a third layer 13. The first layer is from the surface to a first depth. The second layer 12 is from the inside of the first layer 11 to a second depth. The second layer 12 includes 0.05 to 20 volume % of hollow glass or hollow silica 3. The third layer includes 0.05 to 20 volume % of hollow glass or hollow silica 3. The third layer includes 5 to 97 volume % of voids 4 having a diameter of 5 to 500 μm.

[0074] In the foamed resin composition 100, the weight and the dielectric constant of the foamed resin composition 100 are reduced without impairing the strength of the base resin.

[0075] The present invention has been described above by taking the above-mentioned embodiment as an exemplary example. However, the present invention is not limited to the above-mentioned embodiment. That is, the present invention can be applied in various aspects that can be understood by a person skilled in the art within the scope of the present invention.

[0076] A part or all of the above-described embodiments can be described as, but is not limited to, the following supplementary notes.

[0077] (Appendix 1) A base resin with a melt flow rate of 5g / 10min or more, A chemical foaming agent; At least one of hollow glass and hollow silica, Including, A masterbatch characterized by:

[0078] (Appendix 2) For 100 parts by weight of the base resin, 1 to 50 parts by weight of the chemical foaming agent; At least one of the hollow glass and hollow silica particles in an amount of 1 to 50 parts by mass; Contains, 2. The masterbatch according to claim 1,

[0079] (Appendix 3) The base resin is a polystyrene resin. 3. The masterbatch according to claim 1 or 2,

[0080] (Appendix 4) The base resin is The resin is any one of polylactic acid resin, AS resin, ABS resin, polypropylene resin, and polyamide resin. 3. The masterbatch according to claim 1 or 2,

[0081] (Appendix 5) The density of the hollow glass or hollow silica is 0.1 to 0.8 g / cm3. 5. The masterbatch according to claim 1,

[0082] (Appendix 6) The hollow glass or hollow silica has an average particle size of 0.5 to 200 μm. 6. The masterbatch according to claim 1,

[0083] (Appendix 7) The chemical foaming agent is At least one of the following: sodium bicarbonate, ADCA, or nitrogen. 7. The masterbatch according to claim 1,

[0084] (Appendix 8) Melt a base resin with a melt flow rate of 5g / 10min or more, A chemical foaming agent is added to the molten base resin; Adding at least one of hollow glass and hollow silica to the molten base resin, kneading the base resin, the chemical foaming agent, and at least one of the hollow glass and the hollow silica; A method for producing a masterbatch comprising the steps of:

[0085] (Appendix 9) The master batch according to any one of Supplementary Notes 1 to 7 is mixed with pellets of a base resin that serves as a base for molding, and the mixture is dry stirred; controlling the temperature of the dry-mixed mixture of the master batch and the base resin to a temperature at which the chemical foaming agent foams; Carry out molding, A method for molding a foamed resin composition comprising the steps of:

[0086] (Appendix 10) The molding It is injection molding, 10. A method for molding a foamed resin composition according to claim 9.

[0087] (Appendix 11) The molding It is extrusion molding, 10. A method for molding a foamed resin composition according to claim 9.

[0088] (Appendix 12) For 100 parts by mass of the base resin, 20 to 100 parts by mass of the master batch is mixed. 12. A method for molding a foamed resin composition according to any one of claims 9 to 11.

[0089] (Appendix 13) The base resin is It is a modified polyphenylene ether resin. 13. A method for molding a foamed resin composition according to any one of claims 9 to 12.

[0090] (Appendix 14) The base resin is It is a polycarbonate resin. 13. A method for molding a foamed resin composition according to any one of claims 9 to 12.

[0091] (Appendix 15) The base resin is The plasticizer contains at least one of a phosphoric acid ester, a trimellitic acid ester, and a pyromellitic acid ester. A method for molding a foamed resin composition according to any one of claims 9 to 14.

[0092] (Appendix 16) The dry mixing comprises: Including rotation of the stirring blade and supply of air, 16. A method for molding a foamed resin composition according to any one of claims 9 to 15.

[0093] (Appendix 17) A foamed resin composition comprising a base resin and voids 4 formed in the base resin, a first layer from the surface to a first depth; a second layer extending from an inner side of the first layer to a second depth; a third layer inside the second layer; and having The second layer comprises: Contains 0.05 to 20 volume percent of hollow glass or hollow silica, The third layer comprises: The hollow glass or hollow silica is contained in an amount of 0.05 to 20% by volume, Contains 5 to 97% by volume of voids 4 having a diameter of 5 to 500 μm; A foamed resin composition comprising: [Explanation of symbols]

[0094] 1 Base resin 2. Chemical foaming agents 3. Hollow glass or hollow silica 4 void 10 Masterbatch 11 First Layer 12 Second Layer 13 The Third Layer 100 Foamed resin composition

Claims

1. A base resin having a melt flow rate of 5 g / 10 min or more; A chemical foaming agent; At least one of hollow glass and hollow silica, Including, A masterbatch characterized by:

2. For 100 parts by weight of the base resin, 1 to 50 parts by weight of the chemical foaming agent; 1 to 50 parts by weight of at least one of hollow glass and hollow silica; Contains, 2. The masterbatch according to claim 1 .

3. The base resin is a polystyrene resin.

3. The masterbatch according to claim 1 or 2.

4. The density of the hollow glass or hollow silica is 0.1 to 0.8 g / cm3; 3. The masterbatch according to claim 1 or 2.

5. A base resin having a melt flow rate of 5 g / 10 min or more is melted, A chemical foaming agent is added to the molten base resin; Adding at least one of hollow glass and hollow silica to the molten base resin, kneading the base resin, the chemical foaming agent, and at least one of the hollow glass and the hollow silica; A method for producing a masterbatch comprising the steps of:

6. The master batch according to claim 1 or 2 is mixed with pellets of a base resin serving as a base for molding, and the mixture is dry stirred, controlling the temperature of the dry-mixed mixture of the master batch and the base resin to a temperature at which the chemical foaming agent foams; Carry out molding, A method for molding a foamed resin composition comprising the steps of:

7. For 100 parts by mass of the base resin, 20 to 100 parts by mass of the master batch is mixed. A method for molding the foamed resin composition according to claim 6.

8. The base resin is It is a modified polyphenylene ether resin. A method for molding the foamed resin composition according to claim 6.

9. The base resin is It is a polycarbonate resin. A method for molding the foamed resin composition according to claim 6.

10. The dry mixing comprises: Including rotation of the stirring blade and supply of air, A method for molding the foamed resin composition according to claim 6.

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