Injection molding method and molding resin composition

Abstract

To provide an injection molding method for obtaining a molded product having a structure in which a core part and a shell part are formed of different resins by one injection molding of a resin composition.SOLUTION: In an injection molding method, a resin composition for molding containing at least two resins having different apparent viscosity at 230°C and at least one compatibility accelerator is used as a raw material for injection molding.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an injection molding method. and Molding resin composition To things Regarding. [Background technology]

[0002] Injection molding is a molding method that uses a mold. A material such as resin is heated and melted, fed into a mold, and then cooled to form the material into a desired shape. Injection molding is used in a wide range of fields because it allows the rapid mass production of articles of desired shapes.

[0003] For example, Patent Document 1 discloses a molded article having excellent impact resistance, which is obtained by injection molding a resin composition containing a styrene-based resin, polylactic acid, and a copolymer of butadiene and an ethylenically unsaturated carboxylate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-199654 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventionally, in order to produce a molded body using different resins to form a core part and a shell part covering the core part, it is not possible to perform the production by a single injection molding, but rather requires multiple steps such as two-color molding or painting. Patent Document 1 does not consider the production of a molded body having a structure having a core part and a shell part.

[0006] The present disclosure has been made in consideration of the above, and an object of the present disclosure is to provide an injection molding method by which a molded article having a structure in which a core portion and a shell portion are formed of different resins can be obtained by injection molding a resin composition in a single run, a molding resin composition used in the method, and a molded article obtained by the method. [Means for solving the problem]

[0007] Specific means for solving the above problems include the following aspects. <1> An injection molding method in which a molding resin composition containing at least two resins having different apparent viscosities at 230°C and at least one compatibilizer is injection molded as a raw material. <2> The resin includes at least two types of resins, a resin A and a resin B, the difference in apparent viscosity between which is the smallest at 230°C is 1000 Pa·s to 50000 Pa·s. <1> 2. The injection molding method according to claim 1 . <3> The apparent viscosity (η A ) to the apparent viscosity (η B ) ratio (η B / η A ) is 0.01 to 0.4. <2> 2. The injection molding method according to claim 1 . <4> The compatibilizer includes a first compatibilizer compatible with the resin A and a second compatibilizer compatible with the resin B. <2> or <3> 2. The injection molding method according to claim 1 . <5> With respect to the total mass of the molding resin composition, the resin A is 40% by mass to 99% by mass, the resin B is 0.1% by mass to 40% by mass, the first compatibilizer is 0.1% by mass to 20% by mass, and the second compatibilizer is 0.1% by mass to 20% by mass. <4> 2. The injection molding method according to claim 1 . <6> The first compatibilizer and the second compatibilizer are both organic compounds. <4> or <5> 2. The injection molding method according to claim 1 . <7> The resin A is a resin containing a structural unit derived from an aromatic hydrocarbon, and the resin B is a resin containing a structural unit derived from an unsaturated aliphatic hydrocarbon. <4> ~ <6> 13. The injection molding method according to claim 12 . <8> the first compatibilizer and the second compatibilizer are copolymers; the content of aromatic hydrocarbon-derived structural units in the first compatibilizer exceeds 50 mass% based on the total structural units of the first compatibilizer; The content of structural units derived from unsaturated aliphatic hydrocarbons in the second compatibilizer is more than 50 mass% based on the total structural units of the second compatibilizer. The above <7> 2. The injection molding method according to claim 1 . <9> At least two resins and at least one compatibilizer, The resin is a molding resin composition comprising at least two types of resins, resin A and resin B, which have the smallest apparent viscosity difference at 230°C between the two types of resins, and the apparent viscosity difference between the two types of resins is 1000 Pa·s to 50000 Pa·s. <10> The apparent viscosity (η A ) to the apparent viscosity (η B ) ratio (η B / η A ) is 0.01 to 0.4. <9> The molding resin composition according to claim 1. <11> The compatibilizer includes a first compatibilizer compatible with the resin A and a second compatibilizer compatible with the resin B. <9> or <10> The molding resin composition according to claim 1. <12> The first compatibilizer and the second compatibilizer are both organic compounds. <11> The molding resin composition according to claim 1. <13> The resin A is a resin containing a structural unit derived from an aromatic hydrocarbon, and the resin B is a resin containing a structural unit derived from an unsaturated aliphatic hydrocarbon. <11> or <12> The molding resin composition according to claim 1. <14> the first compatibilizer and the second compatibilizer are copolymers; the content of aromatic hydrocarbon-derived structural units in the first compatibilizer exceeds 50 mass% based on the total structural units of the first compatibilizer; The content of structural units derived from unsaturated aliphatic hydrocarbons in the second compatibilizer is more than 50 mass% based on the total structural units of the second compatibilizer. The above <13> The molding resin composition according to claim 1. <15> A core portion including a cured product of resin A; A shell portion containing a cured product of resin B and covering at least a part of the core portion; an intermediate portion located between the core portion and the shell portion and including at least one cured product of a compatibilizer; A molded article, wherein the concentrations of the resin A and the resin B each have a distribution that changes continuously from the core portion to the shell portion. <16> The compatibilizer is at least two types. <15> The molded article according to claim 1. <17> The thickness of the shell portion is 300 μm or less. <15> or <16> The molded article according to claim 1. Effect of the Invention

[0008] According to the present disclosure, there are provided an injection molding method for obtaining a molded article having a structure in which a core portion and a shell portion are formed of different resins by injection molding a resin composition once, a molding resin composition used in the method, and a molded article obtained by the method. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic diagram showing the flow of a molten molding resin composition when the molding resin composition is injection molded. [Diagram 2] FIG. 2 is a schematic diagram showing a cross section of a molded body. [Diagram 3] FIG. [Figure 4] 1 is a micrograph showing a cross section of a molded body before and after acetone vapor etching. [Diagram 5] 1 is a micrograph showing a cross section of a molded body before and after acetone vapor etching. [Figure 6] 1 is a micrograph showing the structure of a molded body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of the present disclosure will be described in detail below. However, the present disclosure is not limited to the following embodiment. In the following disclosure, the components (including element steps, etc.) are not essential unless specifically stated. The same applies to numerical values ​​and their ranges, and do not limit the present disclosure. In the present disclosure, the term "step" includes not only a step that is independent of other steps, but also a step that cannot be clearly distinguished from other steps as long as the purpose of the step is achieved. In the present disclosure, a numerical range indicated using "to" includes the numerical values ​​before and after "to" as the lower limit and upper limit, respectively. In the present disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. In the present disclosure, when multiple substances corresponding to each component are present in the composition, the content of each component in the composition means the total content of the multiple substances present in the composition, unless otherwise specified.

[0011] ≪Injection molding method≫ The injection molding method of the present disclosure involves injection molding using as a raw material a molding resin composition containing at least two types of resins having different apparent viscosities at 230°C and at least one type of compatibilizer.

[0012] When a molding resin composition containing at least two types of resins having different apparent viscosities at 230°C and at least one type of compatibilizer is injection molded as a raw material, a molded article having a structure in which the core and shell are formed of different resins can be obtained by injection molding the resin composition once.

[0013] Although the action of the injection molding method of the present disclosure is not clear, it is assumed as follows. FIG. 1 shows a schematic diagram of a molding resin composition containing at least two resins with different apparent viscosities at 230°C, which is melted and injection molded. The molten molding resin composition flows in a mold 5 in the direction 1 in which the molten molding resin composition flows. At this time, according to the principle of fountain flow, the molten low-viscosity resin 3 flows in the mold 5 more quickly than the molten high-viscosity resin 2, and moves quickly to the surface side of the mold 5 along the flow shown by the dotted arrow in FIG. 1. On the other hand, the molten high-viscosity resin 2 flows in the mold 5 later than the molten low-viscosity resin 3, so it is difficult to move to the surface side of the mold and remains in the center of the mold. Then, these resins are naturally cooled by the mold and solidified, and a molded body having a structure having a core part and a shell part as shown in FIG. 2 is formed. At this time, when the high-viscosity resin 2 has a higher viscosity and the difference in apparent viscosity between the high-viscosity resin 2 and the low-viscosity resin 3 is larger, a molded body having a structure having a core part and a shell part is more likely to be formed. Furthermore, since the molding resin composition of the present disclosure contains at least one type of compatibilizer, the presence of the compatibilizer between the at least two types of resins allows the at least two types of resins to adhere to each other without phase separation and to form a single formed body. That is, according to the injection molding method of the present disclosure, a molded article having a structure in which the core portion and the shell portion are formed from different resins can be obtained by a single injection molding of a resin composition. It should be noted that the present disclosure is in no way limited to the above presumed mechanism.

[0014] <Molding resin composition> (resin) In the injection molding method of the present disclosure, the at least two resins having different apparent viscosities at 230 ° C. preferably include resin A and resin B having the smallest apparent viscosity difference at 230 ° C. of 1000 Pa·s to 50000 Pa·s, more preferably resin A and resin B having the smallest apparent viscosity difference at 230 ° C. of 3000 Pa·s to 50000 Pa·s, and even more preferably resin A and resin B having the smallest apparent viscosity difference at 230 ° C. of 5000 Pa·s to 50000 Pa·s. The "two resins having the smallest apparent viscosity difference at 230 ° C. of the at least two resins" can constitute the core or shell in the molded product by having the above-mentioned apparent viscosity difference. In the injection molding method of the present disclosure, for example, when two resins having different apparent viscosities at 230°C are used, the "difference in apparent viscosity at 230°C" refers to the difference in apparent viscosity between the two resins, and the preferred apparent viscosity difference is the same as above. The two resins can each constitute a core portion or a shell portion in the molded product. In the injection molding method of the present disclosure, the "at least two resins having different apparent viscosities at 230° C." does not include the "compatibilizer" described below.

[0015] In the injection molding method of the present disclosure, at least two types of resins having different apparent viscosities at 230°C are selected from the group consisting of resin A and resin B, which have the smallest apparent viscosity difference at 230°C among the at least two types of resins, from the viewpoint that a molded product having a structure in which the core part and the shell part are formed of different resins can be easily obtained by injection molding a resin composition once. A ) to the apparent viscosity (η B ) ratio (η B / η A) is preferably 0.01 to 0.4, more preferably 0.01 to 0.3, and even more preferably 0.01 to 0.2. The "resin A and resin B having the smallest apparent viscosity difference at 230°C among the at least two resins" can respectively constitute the core portion and the shell portion in the molded product by having the above-mentioned apparent viscosity ratio. In the injection molding method of the present disclosure, for example, when two resins having different apparent viscosities at 230° C. are used, the ratio (η B / η A ) is the ratio of the two resins (η B / η A ) and the preferred ratio (η B / η A ) are the same as above, and the two types of resins can each constitute a core portion or a shell portion in the molded product.

[0016] In this disclosure, the apparent viscosity of a resin at 230°C is measured as follows. In detail, the melt volume rate (MVR) is measured based on Appendix C of JIS K7210. Next, the flow value Q (cm 3 / s) is calculated using the MVR value, and the apparent viscosity (Pa s) is calculated.

[0017] The type of the resin is not particularly limited, and may be a homopolymer or a copolymer. When the resin is a copolymer, the resin may be a random copolymer, a block copolymer, or a graft copolymer. The resin is preferably a thermoplastic resin, and may be a thermoplastic elastomer (TPE). Examples of the resin include acrylonitrile-butadiene-styrene copolymer (ABS resin), polystyrene resin (PS resin), polyamide resin (PA resin, such as nylon 6T, nylon 6I, or nylon 9T), polybutylene terephthalate resin (PBT resin), polyethylene terephthalate resin (PET resin), polycarbonate resin (PC resin), polyphenylene sulfide resin (PPS resin), polyphenylene ether resin (PPE resin), polyimide resin (PI resin), polyether ether ketone resin (PEEK resin), liquid crystal polymer resin (LCP resin), high impact polystyrene (HIPS resin), styrene resin, and the like. Examples of suitable resins include styrene butadiene rubber (SBR resin), acrylonitrile-ethylene propylene rubber-styrene copolymer (AES resin), acrylonitrile-acrylic rubber-styrene copolymer (AAS resin), methyl methacrylate-butadiene rubber-styrene copolymer (MBS resin), acrylonitrile-styrene copolymer (AS resin), methyl methacrylate-styrene copolymer (MS resin), polypropylene resin (PP resin), polyethylene resin (PE resin), polymethyl methacrylate resin (PMMA resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), and polyoxymethylene resin (POM resin).

[0018] In the injection molding method of the present disclosure, the types of the at least two resins having different apparent viscosities at 230°C are not particularly limited, but when using two types of resins, Resin A and Resin B, which have the smallest difference in apparent viscosity at 230°C among the at least two resins, it is preferable that Resin A is a resin containing a structural unit derived from an aromatic hydrocarbon, and further, it is preferable that Resin B is a resin containing a structural unit derived from an unsaturated aliphatic hydrocarbon.

[0019] -Resin A- In Resin A of the present disclosure, the type of aromatic hydrocarbon-derived structural unit is not particularly limited, and examples thereof include structural units derived from styrene, α-methylstyrene, (o-, m-, p-)methylstyrene, 1,3-dimethylstyrene, vinylnaphthalene, vinylanthracene, (o-, m-, p-)phthalic acid, bisphenol A, dihalogenated benzenes, xylenol, pyromellitic anhydride, hydroquinone, 4,4'-difluorobenzophenone, ethylene terephthalate, p-hydroxybenzoic acid, and 6-hydroxy-2-naphthoic acid.

[0020] The resin A of the present disclosure may be a homopolymer or a copolymer. When the resin A is a copolymer, the resin A may be a random copolymer, a block copolymer, or a graft copolymer.

[0021] Resin A of the present disclosure is preferably a thermoplastic resin, and may be a thermoplastic elastomer (TPE). Examples of the resin A include acrylonitrile-butadiene-styrene copolymer (ABS resin), polystyrene resin (PS resin), polyamide resin (PA resin, such as nylon 6T, nylon 6I, or nylon 9T), polybutylene terephthalate resin (PBT resin), polyethylene terephthalate resin (PET resin), polycarbonate resin (PC resin), polyphenylene sulfide resin (PPS resin), polyphenylene ether resin (PPE resin), polyimide resin (PI resin), polyether acene (PA) resin, and the like. Examples of such resins include polyether ether ketone resin (PEEK resin), liquid crystal polymer resin (LCP resin), high impact polystyrene (HIPS resin), styrene butadiene rubber (SBR resin), acrylonitrile-ethylene propylene rubber-styrene copolymer (AES resin), acrylonitrile-acrylic rubber-styrene copolymer (AAS resin), methyl methacrylate-butadiene rubber-styrene copolymer (MBS resin), acrylonitrile-styrene copolymer (AS resin), and methyl methacrylate-styrene copolymer (MS resin).

[0022] From the viewpoint of easily obtaining a molded article having a structure in which the core portion and the shell portion are formed of different resins by a single injection molding of the resin composition, the apparent viscosity of the resin A of the present disclosure at 230°C is preferably 2000 Pa·s to 100000 Pa·s, more preferably 5000 Pa·s to 70000 Pa·s, and even more preferably 10000 Pa·s to 50000 Pa·s. Note that in the present disclosure, the apparent viscosity at 230°C is a value calculated based on JIS K7210 Annex C and JIS K7210 Annex JA.8 Results Expression (Formula No. JA.4) as described above.

[0023] The melt flow rate (MFR) of the resin A of the present disclosure is not particularly limited, but from the viewpoint of easily obtaining a molded article having a structure in which the core part and the shell part are formed of different resins by one injection molding of the resin composition, it is preferably 0.01 g / 10 min to 20 g / 10 min, and more preferably 0.01 g / 10 min to 10 g / 10 min. In the present disclosure, the melt flow rate (MFR) is a value measured under conditions of 230°C and a load of 21.18 N in accordance with JIS K7210:1999.

[0024] The tensile strength of the resin A of the present disclosure is not particularly limited, but from the viewpoint of easily obtaining a molded article having a structure in which the core part and the shell part are formed of different resins by a single injection molding of the resin composition, it is preferably 20 MPa to 300 MPa, and more preferably 30 MPa to 300 MPa. In the present disclosure, the tensile strength is a value measured in accordance with ISO527.

[0025] The deflection temperature under load of Resin A of the present disclosure is not particularly limited, but from the viewpoint of easily obtaining a molded article having a structure in which the core part and the shell part are formed of different resins by a single injection molding of a resin composition, the deflection temperature under load is preferably 80° C. to 150° C. at a bending stress of 1.8 MPa, and more preferably 90° C. to 120° C. In the present disclosure, the deflection temperature under load is a value measured in accordance with JIS K7191-1 using the flatwise method at a bending stress of 1.8 MPa.

[0026] -Resin B- In Resin B of the present disclosure, the type of structural unit derived from an unsaturated aliphatic hydrocarbon is not particularly limited, but examples include structural units derived from propylene, ethylene, methyl acrylate, methyl methacrylate, butadiene, and the like.

[0027] Resin B of the present disclosure may be a homopolymer or a copolymer. When Resin B is a copolymer, Resin B may be a random copolymer, a block copolymer, or a graft copolymer.

[0028] Resin B of the present disclosure is preferably a thermoplastic resin, and may be a thermoplastic elastomer (TPE). Examples of resin B include polypropylene resin (PP resin), polyethylene resin (PE resin), polymethyl methacrylate resin (PMMA resin), and acrylonitrile-butadiene-styrene copolymer (ABS resin).

[0029] The apparent viscosity of Resin B of the present disclosure at 230°C is preferably 100 Pa·s to 50,000 Pa·s, and more preferably 100 Pa·s to 10,000 Pa·s, from the viewpoint of easily obtaining a molded article having a structure in which the core and shell are formed of different resins by a single injection molding of the resin composition. Note that in the present disclosure, the apparent viscosity at 230°C is a value calculated based on JIS K7210 Annex C and JIS K7210 Annex JA.8 Results Expression (Formula No. JA.4), as described above.

[0030] The melt flow rate (MFR) of the resin B of the present disclosure is not particularly limited, but is preferably 0.1 g / 10 min to 50 g / 10 min, more preferably 0.5 g / 10 min to 50 g / 10 min, from the viewpoint of easily obtaining a molded article having a structure in which the core part and the shell part are formed of different resins by one injection molding of the resin composition. Note that, in the present disclosure, the melt flow rate (MFR) is a value measured under the conditions of 230° C. and 21.18 N load in accordance with JIS K7210:1999, as described above.

[0031] The tensile strength of the resin B of the present disclosure is not particularly limited, but from the viewpoint of easily obtaining a molded article having a structure in which the core part and the shell part are formed of different resins by one injection molding of the resin composition, it is preferably 1 MPa to 300 MPa, more preferably 1 MPa to 300 MPa. Note that in the present disclosure, the tensile strength is a value measured in accordance with ISO527 as described above.

[0032] (Compatibilizer) The compatibilizer in the molding resin composition used in the injection molding method of the present disclosure preferably contains a first compatibilizer compatible with the resin A and a second compatibilizer compatible with the resin B. In the molding resin composition used in the injection molding method of the present disclosure, by containing the first compatibilizer compatible with the resin A and the second compatibilizer compatible with the resin B, the molded body molded by the injection molding method has a structure in which, from the surface side of the molded body toward the inside side of the molded body, a part mainly containing resin B, a part mainly containing resin B and the second compatibilizer, a part mainly containing the second compatibilizer and the first compatibilizer, a part mainly containing the first compatibilizer and resin A, and a part mainly containing resin A are continuously formed. In this case, the part mainly containing resin B and the second compatibilizer is called the "shell part", the part mainly containing the second compatibilizer and the first compatibilizer is called the "middle part", and the part mainly containing the first compatibilizer and resin A is called the "core part". That is, a molded body having a structure in which the core part and the shell part are formed of different resins can be obtained by injection molding the resin composition once. Note that the concentrations of the resin A, resin B, the first compatibilizer, and the second compatibilizer are all continuously distributed in the molded body, so although they are expressed as "parts" (or "portions") such as the shell part, the middle part, or the core part, there is no interface between the parts (portions). Note that the "portion mainly containing component X" means that the part contains more than 50 mass% of component X.

[0033] In addition, when the molding resin composition contains, for example, resin A, resin B, and the first compatibilizer, but does not contain the second compatibilizer, the molded body molded by the injection molding method has a structure in which, from the surface side of the molded body toward the inside side of the molded body, a part mainly containing resin B, a part mainly containing resin B and the first compatibilizer, a part mainly containing the first compatibilizer, a part mainly containing the first compatibilizer and resin A, and a part mainly containing resin A are successively formed. In this case, the part mainly containing resin B and the first compatibilizer is called the "shell part", the part mainly containing the first compatibilizer is called the "middle part", and the part mainly containing the first compatibilizer and resin A is called the "core part". That is, a molded body having a structure in which the core part and the shell part are formed of different resins is obtained by injection molding of the resin composition once. In addition, since the concentrations of the resin A, resin B, and first compatibilizer are all continuously distributed in the molded body, although they are expressed as "parts" (or "segments") such as the shell part, intermediate part, or core part, there are no interfaces between the parts (parts).

[0034] In addition, when the molding resin composition contains, for example, three or more resins having different apparent viscosities at 230° C., it is preferable to contain four or more compatibilizers. When the molding resin composition contains, for example, four or more resins having different apparent viscosities at 230° C., it is preferable to contain six or more compatibilizers. In other words, it is preferable to design the number of types of resins and the number of types of compatibilizers so that the compatibilizer is interposed between each of the cured products of the resins in a molded product obtained by injection molding the molding resin composition.

[0035] Although the type of the compatibilizer of the present disclosure is not particularly limited, it is preferable that all of the compatibilizers of the present disclosure are organic compounds. For example, it is preferable that both the first compatibilizer and the second compatibilizer of the present disclosure are organic compounds.

[0036] In the injection molding method of the present disclosure, the first compatibilizer and the second compatibilizer are copolymers, and the content of aromatic hydrocarbon-derived structural units in the first compatibilizer is preferably more than 50% by mass relative to the total structural units of the first compatibilizer, and the content of unsaturated aliphatic hydrocarbon-derived structural units in the second compatibilizer is preferably more than 50% by mass relative to the total structural units of the second compatibilizer. From the viewpoint of easily obtaining a molded body having a structure in which the core and shell are formed of different resins by a single injection molding of a resin composition, it is more preferable that the content of aromatic hydrocarbon-derived structural units in the first compatibilizer is more than 60% by mass relative to the total structural units of the first compatibilizer, and the content of unsaturated aliphatic hydrocarbon-derived structural units in the second compatibilizer is more than 60% by mass relative to the total structural units of the second compatibilizer.

[0037] The description of the type of aromatic hydrocarbon-derived structural unit in the first compatibilizer is the same as the description of the type of aromatic hydrocarbon-derived structural unit in the resin A of the present disclosure. The description of the unsaturated aliphatic hydrocarbon-derived structural unit in the second compatibilizer is the same as the description of the type of unsaturated aliphatic hydrocarbon-derived structural unit in the resin B of the present disclosure.

[0038] The first compatibilizer contains a structural unit derived from an aromatic hydrocarbon, and the resin A of the present disclosure contains a structural unit derived from an aromatic hydrocarbon, so that the first compatibilizer and the resin A are more easily compatible with each other. Furthermore, when the content of the structural unit derived from an aromatic hydrocarbon in the first compatibilizer is high relative to the total structural units of the first compatibilizer, the first compatibilizer and the resin A are more easily compatible with each other. Similarly, the second compatibilizer contains a structural unit derived from an unsaturated aliphatic hydrocarbon, and the resin B of the present disclosure contains a structural unit derived from an unsaturated aliphatic hydrocarbon, so that the second compatibilizer and the resin B are more easily compatible with each other. Furthermore, when the content of the structural unit derived from an unsaturated aliphatic hydrocarbon in the second compatibilizer is high relative to the total structural units of the second compatibilizer, the second compatibilizer and the resin B are more easily compatible with each other.

[0039] The compatibilizer may be a reactive compatibilizer or a non-reactive compatibilizer. The reactive compatibilizer is a polymer compound having a reactive group. Examples of the reactive group include a maleic anhydride group, a (meth)acrylic acid having a carboxylic acid, an epoxy (glycidyl) group, and an oxazoline group. In addition, a random copolymer, a block copolymer, or a graft copolymer may be used as the non-reactive compatibilizer to adjust the compatibility. Examples of the non-reactive compatibilizer include a styrene-ethylene-styrene copolymer, a styrene-ethylenebutylene-styrene copolymer, and modified products thereof. More specifically, examples of the compatibilizer include a hydrogenated styrene-based thermoplastic elastomer (SEBS). Examples of the hydrogenated styrene-based thermoplastic elastomer (SEBS) include a polymer obtained by hydrogenating the double bond portion of a block copolymer made of styrene and butadiene.

[0040] (ratio) In the molding resin composition used in the injection molding method of the present disclosure, it is preferable that the resin A is 40% by mass to 99% by mass, the resin B is 0.1% by mass to 40% by mass, the first compatibilizer is 0.1% by mass to 20% by mass, and the second compatibilizer is 0.1% by mass to 20% by mass, based on the total mass of the molding resin composition. From the viewpoint that a molded body having a structure in which the core part and the shell part are formed of different resins can be easily obtained by injection molding the resin composition once, it is more preferable that the resin A is 60% by mass to 98% by mass, the resin B is 1% by mass to 30% by mass, the first compatibilizer is 0.3% by mass to 10% by mass, and the second compatibilizer is 0.3% by mass to 10% by mass, based on the total mass of the molding resin composition.

[0041] (Other Ingredients) The molding resin composition used in the injection molding method of the present disclosure may contain other components within the scope of the present disclosure. The other components may be mixed in advance with the resin A, for example, or may be mixed in advance with the resin B. For example, by mixing the resin B and other components in advance, preparing a molding resin composition, and then injection molding the molding resin composition, a molded body can be produced in which the concentration of the components is high in the shell portion but low in the core portion.

[0042] <Injection molding method> The injection molding method of the present disclosure is not particularly limited. The runner used in the injection molding may be a cold runner system or a hot runner system. The gate used in the injection molding may be a single gate or a multiple gate system.

[0043] The detailed conditions of the injection molding are not particularly limited, but conditions such as molding temperature, nozzle temperature, mold temperature, weighing value, weighing speed, injection speed (IS), injection speed (VP), filling dwell pressure, filling dwell pressure time, cooling time, and injection peak pressure can be appropriately set by a person skilled in the art.

[0044] ≪Resin composition for molding≫ The molding resin composition of the present disclosure includes at least two types of resins and at least one type of compatibilizer, and the resins include resin A and resin B which have the smallest apparent viscosity difference at 230°C between the at least two types of resins and have an apparent viscosity difference of 1000 Pa s to 50000 Pa s.

[0045] As described above, a molded body having a core and a shell is formed from the principle of fountain flow due to the difference in apparent viscosity between resin A and resin B. Furthermore, by including at least one compatibilizer, the at least two resins are bonded to each other without phase separation by the presence of the compatibilizer between the at least two resins, and the at least two resins are bonded to each other to form a single molded body. That is, according to the molding resin composition of the present disclosure, a molded article having a structure in which the core and shell are formed from different resins can be obtained by a single injection molding of the resin composition.

[0046] (resin) In the molding resin composition of the present disclosure, the difference in apparent viscosity between resin A and resin B at 230°C is preferably 1000 Pa·s to 50000 Pa·s, more preferably 3000 Pa·s to 50000 Pa·s, and even more preferably 5000 Pa·s to 50000 Pa·s, from the viewpoint that a molded article having a structure in which the core portion and the shell portion are formed of different resins can be easily obtained by injection molding of the resin composition once. Note that, in the case where, for example, two resins having different apparent viscosities at 230°C are used in the molding resin composition of the present disclosure, the "difference in apparent viscosity at 230°C" is the difference in apparent viscosity between the two resins, and the preferable difference in apparent viscosity is the same as above. In the molding resin composition of the present disclosure, the "at least two types of resins" does not include the "compatibilizer" described below.

[0047] In the molding resin composition of the present disclosure, Resin A and Resin B are each selected from the group consisting of resins having an apparent viscosity at 230° C. (η A ) to the apparent viscosity (η B ) ratio (η B / η A In the molding resin composition of the present disclosure, for example, when two resins having different apparent viscosities at 230° C. are used, the ratio (η B / η A ) is the ratio of the two resins (η B / η A ) and the preferred ratio (η B / η A ) is the same as above.

[0048] In the present disclosure, the apparent viscosity of the resin at 230° C. is calculated based on the results shown in JIS K7210 Appendix C and JIS K7210 Appendix JA.8 (Formula No. JA.4) as described above.

[0049] The type of the resin is not particularly limited, and the description of the resin in the molding resin composition of the present disclosure, including definitions, examples, preferred embodiments, and the like, is the same as the description of the resin in the injection molding method of the present disclosure.

[0050] In the molding resin composition of the present disclosure, the types of resin A and resin B are not particularly limited, but it is preferable that resin A is a resin containing a structural unit derived from an aromatic hydrocarbon, and further, it is preferable that resin B is a resin containing a structural unit derived from an unsaturated aliphatic hydrocarbon.

[0051] -Resin A- The description of resin A in the molding resin composition of the present disclosure, including definitions, examples, preferred embodiments, and the like, is the same as the description of resin A in the injection molding method of the present disclosure.

[0052] -Resin B- The description of Resin B in the molding resin composition of the present disclosure, including definitions, examples, preferred embodiments, and the like, is the same as the description of Resin B in the injection molding method of the present disclosure.

[0053] (Compatibilizer) The description of the compatibilizer in the molding resin composition of the present disclosure, including definitions, examples, preferred embodiments, and the like, is the same as the description of the compatibilizer in the injection molding method of the present disclosure.

[0054] (ratio) The explanation of the ratio in the molding resin composition of the present disclosure, including definitions, examples, preferred embodiments, etc., is the same as the explanation of the ratio in the injection molding method of the present disclosure.

[0055] (Other Ingredients) The explanation of the other components in the molding resin composition of the present disclosure, including definitions, examples, preferred embodiments, and the like, is the same as the explanation of the other components in the injection molding method of the present disclosure.

[0056] <Method for preparing molding resin composition> In the molding resin composition of the present disclosure, the method of preparing the molding resin composition is not particularly limited, and the molding resin composition can be prepared by a known method. For example, various raw materials are mixed in advance using a mixing device such as a mixer type mixer, a V-type blender, and a tumbler type mixer, and the mixture is melt-kneaded to prepare the molding resin composition. The melt-kneading device is also not particularly limited, and examples thereof include a Banbury type mixer, a kneader, a roll, a single-screw extruder, a special single-screw extruder, and a twin-screw extruder.

[0057] The molding resin composition of the present disclosure may be molded into a known form by a known method. For example, the molding resin composition of the present disclosure may be molded into pellets using a pelletizer, or into flakes using a known device, or into pulverized products thereof.

[0058] When the molding resin composition of the present disclosure, or a cured product of the molding resin composition formed into, for example, pellets, is injection molded, a molded article having a core-shell structure can be produced due to the difference in viscosity between Resin A and Resin B.

[0059] <Molded body> The molded article of the present disclosure has a core portion including a cured product of resin A, a shell portion including a cured product of resin B and covering at least a portion of the core portion, and an intermediate portion located between the core portion and the shell portion and including a cured product of at least one kind of compatibilizer, and the concentrations of resin A and resin B each have a distribution that changes continuously from the core portion to the shell portion.

[0060] Fig. 3 is an enlarged view of the area enclosed by the dotted square frame in the cross-sectional view of Fig. 2. As shown in Fig. 3, in the molded product of the present disclosure, the shell portion 4, the intermediate portion 7, and the core portion 6 change in a gradational manner from the surface 8 side of the molded product toward the inside of the molded product.

[0061] In the molded article of the present disclosure, the core portion containing the cured product of resin A may contain the cured product of resin B, that is, resin B may be finely dispersed in the core portion. Furthermore, in the molded article of the present disclosure, the shell portion containing the cured product of resin B may contain the cured product of resin A, that is, resin A may be finely dispersed in the shell portion. In other words, the molded article of the present disclosure may change in a gradational manner from the shell portion to the intermediate portion and then to the core portion.

[0062] In the molded article of the present disclosure, it is preferable that there are at least two types of compatibilizers.

[0063] In the molded product of the present disclosure, the thickness of the shell portion is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less. Conventionally, when a molded product having a core portion and a shell portion is produced by, for example, two-color molding, the thickness of the shell portion becomes 1 mm or more. Compared with conventional molded products having a core portion and a shell portion, the molded product of the present disclosure has a very thin shell portion.

[0064] In the molded article of the present disclosure, the shell portion may cover at least a portion of the core portion, and may cover the entire core portion.

[0065] The cross-sectional structure of the molded article of the present disclosure can be identified, for example, by cutting a thin section from the molded article of the present disclosure with a microtome and observing the thin section with a microscope.

[0066] In the molded article of the present disclosure, the concentrations of the resin A and the resin B each have a distribution that changes continuously from the core portion to the shell portion. More specifically, in the molded article, the concentration of the resin A has a distribution that decreases continuously from the core portion to the shell portion, and the concentration of the resin B has a distribution that increases continuously from the core portion to the shell portion.

[0067] The resin concentration in the molded product of the present disclosure can be determined, for example, by cutting a slice from the molded product of the present disclosure with a microtome and analyzing the slice with infrared spectroscopy (IR). Alternatively, it can be confirmed that the concentrations of resin A and resin B each have a distribution that changes continuously from the core to the shell, for example, by cutting a slice from the molded product of the present disclosure and analyzing the slice with a transmission electron microscope (TEM). EXAMPLES

[0068] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to the following examples as long as it does not deviate from the gist of the disclosure. In addition, unless otherwise specified, "parts" are based on mass. "%" is also based on mass.

[0069] <Examples 1 to 3 and Comparative Examples 1 to 5> (Preparation of test samples) For Examples 1 to 3 and Comparative Examples 1 to 5, resin compositions for injection molding were prepared with the compounding ratios of each component shown in Table 1 below. In detail, using a kneading extruder, each component was kneaded under the conditions of a nozzle temperature of 230°C to 245°C, an intermediate temperature (temperature of the kneading section) of 230°C to 245°C, a hopper temperature of 160°C to 180°C, a screw rotation speed of 60 rpm, and a feed rate of 3.0 g / min to 4.0 g / min to prepare a resin composition for injection molding. Furthermore, the resin composition for injection molding was dried under the conditions of 80°C and 12 hours to prepare pellets of the resin composition for injection molding.

[0070] [Table 1]

[0071] Details of the compounds and abbreviations listed in Table 1 are shown below. ABS(a): Resin A of the present disclosure Acrylonitrile-Butadiene-Styrene Copolymer Apparent viscosity 2500Pa·s MFR (230℃, 21.18N load) 3g / 10min Tensile strength: 51MPa Deflection temperature under load (1.8MPa) 95℃ ABS(b): Resin A of the present disclosure Acrylonitrile-Butadiene-Styrene Copolymer Apparent viscosity 10730Pa·s MFR (230℃, 21.18N load) 0.7g / 10min Tensile strength: 50MPa Deflection temperature under load (1.8MPa) 101℃ PP(a): Resin B of the present disclosure Polypropylene Resin Apparent viscosity 2500Pa·s MFR (230℃, 21.18N load) 3g / 10min Tensile strength: 37MPa Homopolymer PP(b): Resin B of the present disclosure Polypropylene Resin Apparent viscosity 840Pa·s MFR (230℃, 21.18N load) 9g / 10min Tensile strength: 29MPa Copolymer Compatibilizer (a): the first compatibilizer of the present disclosure Hydrogenated styrenic thermoplastic elastomer (SEBS) Styrene / ethylene / butylene mass ratio 67 / 33 Compatibilizer (b): the second compatibilizer of the present disclosure Hydrogenated styrenic thermoplastic elastomer (SEBS) Styrene / ethylene / butylene mass ratio 20 / 80 · Apparent viscosity difference: The difference in apparent viscosity between Resin A and Resin B at 230°C. ·η B / η A : Apparent viscosity of resin A at 230°C (η A ) to the apparent viscosity (η B ) ratio. -: The substance is not blended into the resin composition for injection molding.

[0072] The pellet-shaped resin composition for injection molding was injection molded under the conditions of a molding temperature of 250°C, a nozzle temperature of 250°C, a mold temperature of 70°C, a weighing value of 13.5 mm, a weighing speed of 2 mm, an injection speed (IS) of 30 mm / s, an injection speed (VP) of 5.2 mm, a filling dwell pressure of 90%, a filling dwell time of 15 sec, a cooling time of 15 sec, and an injection peak pressure of 111% to 118%.

[0073] By the injection molding, rectangular test samples having a length of 50 mm, a width of 5 mm, and a thickness of 2 mm were prepared.

[0074] (chloroform immersion) A test piece with a length of 15 mm, a width of 5 mm, and a thickness of 2 mm was cut out from each of the rectangular test samples. Each test piece was immersed in a chloroform solution of 99% by mass or more at 25±5°C for 120 hours. When the test samples of Comparative Example 1 and Comparative Example 2 were immersed in chloroform, the ABS dissolved and the chloroform solution changed from transparent to black. On the other hand, in Comparative Example 5 and Example 3, the ABS did not dissolve and the chloroform solution remained transparent. This is because ABS is easily dissolved in chloroform and PP is difficult to dissolve in chloroform. That is, when the apparent viscosities of resin A and resin B at 230°C are different from each other as in Comparative Example 5 and Example 3, a molded body with a core-shell structure was obtained in which PP is mainly present in the shell and ABS is mainly present in the core.

[0075] (Cross-section acetone vapor etching) After embedding in epoxy resin and polishing the cross-section, the cross-section of each rectangular test sample was observed at approximately the center in the longitudinal direction at 50x or 200x magnification with ring light or incident light. After observation, the test sample was set on a container containing acetone so that the cross-section of the test sample faced the acetone. Care was taken not to directly touch the test sample with acetone, and the test sample was etched with acetone vapor at 25±5°C for 60 seconds. The cross-section was then observed again at 50x or 200x magnification with ring light or incident light. A microscope was used to observe the cross-section. The results of the cross-section observation are shown in Figures 4 and 5. In Figures 4 and 5, the observation results at 200x magnification are enlarged views of the area within the dotted square frame at the upper right of each cross-section observed at 50x magnification.

[0076] When the cross-sections of the test samples before acetone vapor etching were observed, a 100 μm-thick shell portion (a portion mainly containing PP) was confirmed on the surface side of the test samples (i.e., the outer side of the cross-sections of the test samples) in Examples 1 to 3 and Comparative Examples 3 to 5. When the cross sections of the test samples after etching with acetone vapor were observed, differences in color intensity were confirmed between the shell and core parts in Comparative Examples 1, 3, 4, and 5, which did not contain a compatibilizer, and the boundary between the shell and core parts was clear. This is because ABS does not have acetone resistance, so the core part (part mainly containing ABS) was etched by acetone vapor, and the cracks in the ABS appeared white. Furthermore, because PP has acetone resistance, the shell part (part mainly containing PP) was not easily etched by acetone vapor and remained black. On the other hand, in Comparative Example 2 and Examples 1 to 3, in which a compatibilizer was added, the difference in color intensity between the shell and core parts was unclear, and the boundary between the shell and core parts was unclear. This is because the compatibilizer caused PP to be mixed into the core part (part mainly containing ABS), improving the acetone resistance of the core part. Furthermore, in particular in Comparative Examples 1 and 2, an incomplete core-shell structure was formed in which the shell portion (portion mainly containing PP) was too thin, whereas a core-shell structure with a thick shell portion was formed in particular in Comparative Example 5 and Example 3. That is, when the apparent viscosities at 230°C of resin A and resin B were different, a molded product with a core-shell structure was obtained in which PP was mainly present in the shell portion and ABS was mainly present in the core portion.

[0077] From the above, in Examples 1 to 3, it was possible to provide an injection molding method that can obtain a molded article having a structure in which the core and shell are formed of different resins by injection molding a resin composition once, a molding resin composition used in the method, and a molded article obtained by the method. In Examples 1 to 3, two types of compatibilizers (compatibilizer (a) and compatibilizer (b)) are used. The styrene / ethylene-butylene ratio (mass ratio) of the compatibilizer (a) is 67 / 33, which means that the styrene ratio is high, that is, the ratio of structural units derived from aromatic hydrocarbons is high. Therefore, the compatibilizer (a) was easily compatible with ABS, which has structural units derived from aromatic hydrocarbons (styrene). On the other hand, the styrene / ethylene-butylene ratio (mass ratio) of the compatibilizer (b) is 20 / 80, which means that the ethylene-butylene ratio is high, that is, the ratio of structural units derived from unsaturated aliphatic hydrocarbons is high. Therefore, the compatibilizer (b) was easily compatible with PP, which has structural units derived from unsaturated aliphatic hydrocarbons (propylene). In other words, the molded bodies produced in Examples 1 to 3 had a structure, which was successively arranged from the surface side of the molded body toward the interior side of the molded body, a portion mainly containing PP, a portion mainly containing PP and compatibilizer (b), a portion mainly containing compatibilizer (b) and compatibilizer (a), a portion mainly containing compatibilizer (a) and ABS, and a portion mainly containing ABS.

[0078] (Transmission electron microscope (TEM) analysis of molded body) A thin piece was cut out from a test piece having a length of 10 mm, a width of 5 mm, and a thickness of 2 mm, which was prepared under the conditions of Example 3 described above. Using a transmission electron microscope (TEM), the dispersion distribution of resin A and resin B from the core part to the shell part in the test piece was observed. The observation points were four in total (the outermost surface side of the test piece, and depths of about 50 μm, about 100 μm, and about 150 μm from the outermost surface side).

[0079] The observation results are shown in Figure 6. The length of each scale bar shown in the lower right of the figure is 2.0 μm. The phase thought to be an aliphatic hydrocarbon-based material was amorphous, and the size of the phase tended to increase with increasing depth from the outermost surface. Meanwhile, the total amount of aliphatic hydrocarbon-based material in the entire observation field tended to increase from the inner side to the outermost surface. A layer-separated structure (i.e., a core-shell structure) was observed within the phase, and two types of island phases were observed to be dispersed: amorphous island phases with lamellar structures and circular island phases. Furthermore, a portion thought to contain more compatibilizer was observed between the inner side and the outermost surface side compared to the inner side and the outermost surface side. That is, in the test sample (i.e., the molded article of the present disclosure), resin A and resin B each had a distribution that changed continuously from the core portion (inner side) toward the shell portion (outermost surface side). Furthermore, it was confirmed that the test sample had an intermediate portion located between the core portion and the shell portion and containing a relatively large amount of compatibilizer, and was a molded article as shown in Figure 3. It was therefore confirmed that resin A was compatible with the first compatibilizer, and resin B was compatible with the second compatibilizer.

[0080] <Examples 3 to 5 and Comparative Examples 6 and 7> (Preparation of test samples) In addition to the above-mentioned Example 3, further, as Example 4 and Example 5, resin compositions for injection molding were prepared in the same manner as in Examples 1 to 3 and Comparative Examples 1 to 5, with the mixing ratios of each component shown in Table 2 below, and then pellets of the resin compositions for injection molding were produced. As Comparative Examples 6 and 7, resin compositions for injection molding were prepared with the components shown in Table 2 below. Details of the compounds and abbreviations shown in Table 2 are the same as those in Table 1.

[0081] For Examples 3 to 5, the pellets were injection molded from the pellet-shaped resin compositions for injection molding under the conditions shown in Table 2. For Comparative Examples 6 and 7, the resin compositions for injection molding were injection molded under the conditions shown in Table 2. By the above operations, ISO multipurpose test pieces (Test Samples 1 to 6) were each produced.

[0082] [Table 2]

[0083] (Polishing of test specimen) Using test samples 1 to 6, "unpolished test pieces" and "polished test pieces" were prepared. In detail, the "unpolished test pieces" were prepared by using the end (excluding the gate side) of the test sample after the Charpy impact test piece was taken out between the marked lines. In order to prevent chloroform from adhering to and dissolving from the cut surface, the cut surface was sealed with PP(b). On the other hand, the "polished test pieces" were prepared by removing the shell part by polishing one side of the test sample by 1 mm (grain size #120). In addition, the cut surface of the polished test pieces was not sealed.

[0084] (chloroform immersion) 10 ml of chloroform solution of 99% by mass or more was placed in a screw tube bottle (50 ml capacity), and the unpolished test pieces or polished test pieces were immersed with the cut surface facing up for 24 hours at 25±5°C. The condition of each test solution (chloroform solution) and each test piece was observed at regular intervals, and the results are shown in Table 3.

[0085] [Table 3]

[0086] In Table 3, the condition of each test solution (chloroform solution) and each test piece was evaluated on a 5-level scale (5, 4, 3, 2, or 0 points) according to the following criteria. 5 points: The test solution was highly transparent and no black turbidity was observed. 4 points: The test solution was highly transparent, but a slight black turbidity was observed. 3 points: The test solution was not very transparent and was entirely black and turbid. The shape of the test piece was maintained. 2 points: The test solution was dark and turbid, and dissolution was observed to the extent that the test specimen partially lost its shape (swelling is not included). 0 points: The test solution was dark and turbid, and the shape of the test piece was not maintained (swelling is not included).

[0087] In Table 3, "Difference" indicates the difference between the total score for the unpolished test piece and the total score for the polished test piece. "-" indicates that the difference was not calculated.

[0088] In this chloroform immersion test, the presence or absence of chloroform resistance can be confirmed by checking the presence or absence of the core-shell structure of the molded body. For example, in this embodiment, when the molded body has a layer-separated structure (i.e., a core-shell structure), the core part exists on the outermost surface (i.e., the outermost surface is mainly PP, which is difficult to dissolve in chloroform), so the molded body has chloroform resistance. However, when the surface of the molded body having a layer-separated structure is polished and the outermost surface (i.e., PP) is removed, ABS, which is easily dissolved in chloroform, is exposed, so the chloroform resistance of the molded body decreases. Therefore, a molded body with a large difference between the pre-polishing (i.e., "unpolished test piece") and post-polishing (i.e., "polished test piece") was judged to have a layer-separated structure. According to test sample 6 (molded body of ABS alone), the difference between the unpolished test piece and the polished test piece was 4 points, so this was used as the score for the change in resistance to chloroform due to the plate thickness and volume change, and if the difference of the molded body was greater than 4 points, the molded body was judged to have a layer-separated structure (i.e., a core-shell structure).

[0089] That is, in Test Samples 1 to 4, molded bodies having a better core-shell structure were obtained. [Explanation of symbols]

[0090] 1. Flow direction of molten molding resin composition 2. Molten high-viscosity resin 3. Molten low-viscosity resin 4 Shell part 5. Mold 6 Core 7. Middle Section 8 Surface of molded body

Claims

1. An injection molding method comprising injection molding a molding resin composition containing at least two resins having different apparent viscosities at 230°C and at least one compatibilizer, to obtain a molded article having a structure in which a core portion and a shell portion are formed of different resins.

2. The resin includes at least two types of resins, and the difference in apparent viscosity between the two types of resins having the smallest difference in apparent viscosity at 230 ° C. is 1000 Pa s to 50000 Pa s. The injection molding method according to claim 1.

3. The apparent viscosity (η Ａ ) to the apparent viscosity (η Ｂ ) ratio (η Ｂ / Ａ 3. The injection molding method according to claim 2, wherein the ratio of the viscosity of the polymer to the viscosity of the resin is 0.01 to 0.

4.

4. The injection molding method according to claim 2 or 3, wherein the compatibilizer comprises a first compatibilizer compatible with the resin A and a second compatibilizer compatible with the resin B.

5. 5. The injection molding method according to claim 4, wherein, relative to the total mass of the molding resin composition, the resin A is 40% by mass to 99% by mass, the resin B is 0.1% by mass to 40% by mass, the first compatibilizer is 0.1% by mass to 20% by mass, and the second compatibilizer is 0.1% by mass to 20% by mass.

6. The injection molding method according to claim 4 or 5, wherein the first compatibilizer and the second compatibilizer are both organic compounds.

7. The injection molding method according to any one of claims 4 to 6, wherein the resin A is a resin containing a structural unit derived from an aromatic hydrocarbon, and the resin B is a resin containing a structural unit derived from an unsaturated aliphatic hydrocarbon.

8. the first compatibilizer and the second compatibilizer are copolymers; The content of aromatic hydrocarbon-derived structural units in the first compatibilizer exceeds 50 mass% based on the total structural units of the first compatibilizer; The content of structural units derived from unsaturated aliphatic hydrocarbons in the second compatibilizer is more than 50 mass% based on the total structural units of the second compatibilizer. The injection molding method according to claim 7.

9. At least two resins and at least one compatibilizer, The resin includes at least two types of resins, a resin A and a resin B, the difference in apparent viscosity between which is the smallest at 230°C is 1000 Pa·s to 50000 Pa·s, A molding resin composition which can give a molded article having a structure in which a core part and a shell part are formed from different resins.

10. The apparent viscosity (η Ａ ) to the apparent viscosity (η Ｂ ) ratio (η Ｂ / Ａ 10. The molding resin composition according to claim 9, wherein the molar ratio of the molar ratio of the resin composition to the molar ratio of the

11. The molding resin composition according to claim 9 or 10, comprising, as the compatibilizer, a first compatibilizer compatible with the resin A and a second compatibilizer compatible with the resin B.

12. The molding resin composition according to claim 11 , wherein the first compatibilizer and the second compatibilizer are both organic compounds.

13. 13. The molding resin composition according to claim 11, wherein the resin A is a resin containing structural units derived from aromatic hydrocarbons, and the resin B is a resin containing structural units derived from unsaturated aliphatic hydrocarbons.

14. the first compatibilizer and the second compatibilizer are copolymers; The content of aromatic hydrocarbon-derived structural units in the first compatibilizer exceeds 50 mass% based on the total structural units of the first compatibilizer; The content of structural units derived from unsaturated aliphatic hydrocarbons in the second compatibilizer is more than 50 mass% based on the total structural units of the second compatibilizer. The molding resin composition according to claim 13.

15. The molded body is A core portion including a cured product of resin A; A shell portion containing a cured product of resin B and covering at least a part of the core portion; an intermediate portion located between the core portion and the shell portion and including at least one cured product of a compatibilizer; The injection molding method according to claim 1 , wherein the concentrations of the resin A and the resin B each have a distribution that changes continuously from the core portion to the shell portion.

16. 16. The injection molding process of claim 15, wherein the compatibilizer is at least two types.

17. The injection molding method according to claim 15 or 16, wherein the shell portion has a thickness of 300 μm or less.

Images