Resin composition with metallic effect, and impact-resistant component

Abstract

Resin composition with a metallic effect, which is - thermoplastic resin containing polycarbonate, - a glitter material and - contains a hydrogenated styrene-based thermoplastic elastomer with a 300% tensile stress of more than 0 and less than 12.6 MPa.

Description

[Technical field]

[0001] The present invention relates to a metallic-effect resin composition and an impact-resistant member formed therefrom. More particularly, the present invention relates to a metallic-effect resin composition having improved impact resistance. [State of the art]

[0002] Conventionally, as a high gloss resin, a resin coated with a metallic effect material has been prepared by melt-kneading a glitter material containing a metal such as aluminum, glass, mica, or the like, a coloring material, a stabilizer, and the like with a resin base.

[0003] In order to develop an add-on part made of metallic effect material that complies with the legal requirements for vehicle interiors, a resin base material with high impact resistance was selected and colored with the above-mentioned glitter material in such a way as to achieve a metallic effect. However, the problem that arose was that the impact resistance was significantly reduced.

[0004] To solve such problems of reduced impact strength, a known technology is available that consists of using an aluminum pigment with an adherent resin to which a specific resin is bonded (see Patent Literature 1). This technology is disclosed, for example, in DE 603 ​​00 326 T2, but requires special resins such as polymers containing a unit such as carboxylic acids with radically polymerizable double bonds and a unit derived from a monomer with two or more radically polymerizable double bonds. It is also necessary to produce the aluminum pigment with an adherent resin by bonding them to the aluminum pigment. In other words, the technology disclosed in the patent literature requires special resins and a complex process. [Literature list][Patent literature] [Patent Literature 1] JP 2018-123328 A [Patent literature 2] DE 603 ​​00 326 T2 [Summary of the invention][Object of the invention]

[0005] The aim is to produce a resin composition with improved impact resistance and metallic effect color, regardless of the type and appearance of the glitter material. [Means of solving the problem]

[0006] After intensive research efforts, the inventor discovered that a resin composition containing a resin base material, a glitter material, and further a modifying agent made of a specific resin glitter can provide a resin molded product having sufficient impact resistance, the product having a metallic effect coloration due to the glitter material, thus completing the invention.

[0007] That is, the present invention according to claim 1 relates to a metallic effect resin composition comprising a thermoplastic resin containing polycarbonate, a glitter material and a hydrogenated styrene-based thermoplastic elastomer having a 300% tensile stress of more than 0 and less than 12.6 MPa. [Advantageous effects of the invention]

[0008] According to the metallic effect resin composition of the present invention, it is possible to obtain a resin molded product that appears colored due to a glitter material and that is impact-resistant. The metallic effect resin compositions of the present invention are further advantageous in that it is possible to produce resin molded products with metallic effect coloration using any general-purpose glitter materials, without requiring the use of a glitter material of a specific type or appearance. [Embodiment of the invention]

[0009] Embodiments of the present invention will be described below. However, the present invention is not limited to the embodiments described below. [Resin composition with metallic effect]

[0010] The thermoplastic resin is a main component of the resin composition. In this specification, the thermoplastic resin is also referred to as the base resin. The thermoplastic resins include polycarbonate (PC) or blends of polycarbonate (PC) with polypropylene (PP), e.g., homopolypropylene, polymethyl methacrylate (PMMA), polyamide (PA), acrylonitrile-butadiene-styrene copolymer (ABS), acrylonitrile-ethylene-propylene-diene-styrene copolymer (AES), or modified resins thereof. The thermoplastic resin can be appropriately selected by one skilled in the art depending on the applications of the metallic effect resin composition. For example, when the metallic effect resin composition is a structural member for automotive interiors, polycarbonate (PC) is used as the thermoplastic resin according to the present invention.This is because it is desirable for automotive interior components to have a certain degree of rigidity, heat resistance, and light resistance. According to the invention, the thermoplastic resin contains polycarbonate (PC).

[0011] The glitter material is a material that imparts luster to the resin composition according to the present embodiment, and is preferably a material that imparts a metallic color to the resin composition according to the present invention. Aluminum pigments such as aluminum flakes, vapor-deposited aluminum, and colored aluminum can be used as the glitter material.Other pigments include, but are not limited to, luster pigments such as interference mica pigments, white mica pigments, and graphite pigments; metal oxide pigments such as titanium oxide and iron oxide; composite metal oxide pigments such as titanium yellow; color pigments such as carbon black, azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, perylene pigments, perinone pigments, benzimidazolone pigments, isoindoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, indanthrone pigments, dioxane pigments, and indigo pigments; and pigment extenders such as clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, talc, silica, and aluminum oxide white.

[0012] The shape of the glitter material is not particularly limited; for example, it can be valley-shaped or flake-shaped. Regarding the particle size of the glitter material, the average particle size can preferably be 1 to 100 µm, especially 5 to 50 µm, although it is not limited to a specific range of average particle size.

[0013] According to a preferred embodiment, the glitter material is a metal, inorganic flakes with a deposited metal, thermosetting resins with a deposited metal, which can impart a silver metallic effect to the resin composition, and in particular, aluminum glitter material. The aluminum glitter material can be any material containing aluminum pigment. The aluminum pigment can be used as such, or it can be a masterbatch, wherein the aluminum pigment is incorporated into a resin or the like.

[0014] The content of the glitter material in the resin composition can be, for example, 1 to 10 parts by mass, preferably 1 to 5 parts by mass, based on 100 parts by mass of the resin base, regardless of whether the glitter material is an aluminum glitter material or a glitter material consisting primarily of pigments other than aluminum. However, the content of the glitter material is not subject to any specific content range.

[0015] The modifying agent is added to the resin composition according to the present embodiment along with the glitter material to impart impact resistance to the resin molded product obtained from the resin composition. A hydrogenated styrene-based thermoplastic elastomer having a 300% tensile stress of greater than 0 and less than 12.6 MPa is used as the modifying agent. The 300% tensile stress is a property of the modifying agent itself before it is added to the resin composition, and it represents a value measured according to ISO 37.The hydrogenated styrene-based thermoplastic elastomer having such physical properties is considered capable of improving the impact resistance of the resin composition by being present between the resin base and a glitter material such as aluminum pigment in such a way that only the elastomer having a low elastic modulus is deformed when the resin composition undergoes deformation, thus preventing deformation and destruction of the glitter material.

[0016] The 300% tensile stress of the hydrogenated styrene-based thermoplastic elastomer is preferably greater than 0 and at most 8.3 MPa, further preferably greater than 0 and at most 6.0 MPa, even more preferably greater than 0 and at most 4.4 MPa, and most preferably at least 2.5 MPa and at most 4.4 MPa. Such a low-stress elastomer is prone to stress release upon deformation and is less likely to accumulate energy. Therefore, even under the action of severe deformation, it is less likely to be destroyed and can thus contribute to further improving impact resistance.

[0017] The hydrogenated styrene-based thermoplastic elastomer preferably has an elongation at break of more than 460%. The elongation at break is also a property of the modifying agent itself before it is added to the resin composition, and it is again a value measured according to ISO 37. In particular, the elongation at break is at least 490%. The higher the upper limit, the better, and it may, for example, be set at approximately 1500% or less. In the resin composition, it is assumed that breakage of the hydrogenated styrene-based thermoplastic elastomer will also result in breakage of the glitter material. Therefore, an elastomer that exhibits a lower tendency to break when subjected to severe deformation can contribute to further improving impact resistance.

[0018] The hydrogenated styrene-based thermoplastic elastomer is a polymer that satisfies the above-mentioned physical properties and has a repeating unit of hydrogenated styrene. The structural properties of the polymers are not particularly limited; preference is given to those that contain a repeating unit such as ethylene, butylene, and butadiene in addition to styrene.

[0019] The content of the modifying agent in the metallic effect resin composition can be 1 to 10 parts by mass, preferably 1 to 5 parts by mass, based on 100 parts by mass of the resin composition. However, the modifying agent content is not subject to any specific content range.

[0020] However, the resin composition of the present invention may contain other ingredients in addition to the thermoplastic resin (resin base material), the glitter material, and the modifying agent, as long as the properties are not impaired. Other ingredients include, but are not limited to, flame retardants, antioxidants, dispersants, plasticizers, stabilizers, and colorants other than glitter materials. [Method for producing a resin composition]

[0021] A method for producing the resin composition of the present invention is described below. The method for producing the resin composition can be carried out, for example, by dry-mixing the components of the composition, including the respective pellets of the resin base, the glitter material, and the modifying agent, in a single container, followed by melt-kneading and pelletizing the composition using a twin-screw extruder or the like, but there is no limitation to any specific method.

[0022] The metallic effect resin composition according to the present embodiment, as obtained in this manner, is not particularly limited in its form and can be in a flowable or solid form as long as it has the specific composition described in detail above. The metallic effect resin composition exhibits both gloss properties and impact resistance when formed into a solid molded product. [Resin molded product with metallic effect]

[0023] The metallic effect resin composition of the present invention can be molded into a predetermined shape to obtain a metallic effect resin molded product. The molding method is not particularly limited; the pelletized resin composition can be injected into a mold having the desired shape, which may be heated to a desired temperature for molding. Other molding methods such as extrusion, compression molding, injection molding, and blow molding can also be used.

[0024] The metallic effect resin molded product can be used as an impact-resistant member alone or in combination with other components, members, or the like. For example, the impact-resistant member may be a member for automotive interiors. Specific automotive interiors may include, but are not limited to, switch knob panels, navigation device bezels, audio device bezels, gearshift bezels, instrument panel trim, door frame trim, and gauge assemblies. As another example, the impact-resistant member may be one of the components that make up electrical appliances and household items.

[0025] In the metallic effect resin molded product according to the present embodiment, the resin composition has a specific composition, thus exhibiting a desirable appearance attributable to the glitter material and being impact-resistant, and can further find widespread use in various application fields. In particular, in compositions containing a glitter material containing a metal or an inorganic compound and having a particle size of more than several micrometers, or a glitter material containing a brittle resin particle, deterioration in impact resistance has conventionally been a major problem. According to the present embodiment, even resin molded products containing such glitter materials are advantageous in that they provide sufficient impact resistance and a desirable appearance. [Examples]

[0026] The present invention will be described in more detail below with reference to the examples below. However, the present invention is not limited to the examples mentioned below.

[0027] The metallic effect resin compositions of Examples and Comparative Examples were prepared. In both the Examples and Comparative Examples, a polycarbonate resin (product name: Panlite SS2525Z, manufactured by Teijin Ltd.) was used as the thermoplastic resin serving as the resin base material, and an aluminum pigment masterbatch (product name: NHff-A-05CB50, Nagase & Co., Ltd.) was used as the glitter material. The masterbatch used is described below. The resin base material was an acrylonitrile-styrene copolymer, the aluminum content was 50 mass%, and the aluminum was valley-shaped, with the aluminum particle size being 5 μm. The amount of glitter material added is shown in Table 2 below.

[0028] The hydrogenated styrene-based thermoplastic elastomer manufactured by Asahi Kasei Corporation was used as the modifying agent in all of Examples 1 to 5 and Comparative Example 3. Details of the modifying agent used are shown in Table 1. SOE (registered trademark) is a hydrogenated styrene-butadiene copolymer. Tuftec (registered trademark) M Series is a hydrogenated styrene-ethylene-styrene copolymer. Tuftec (registered trademark) H Series is a modified M Series (the model numbers in Examples 4 and 5 are acid modified). Both the elongation at break and the 300% tensile stress are physical properties of the hydrogenated styrene-based thermoplastic elastomer alone before it is added to the resin composition, and they are values ​​measured according to ISO 37.The amount of modifying agent added is listed below in Table 2.

[0029] To prepare the metallic effect resin composition, the polycarbonate resin, aluminum glitter, and modifying agent were blended, and pellets of the resin base, aluminum MB, and modifying agent were dry-blended in a single container. They were then melt-kneaded in a twin-screw extruder (HYPERKTX 30 SHT-HS, manufactured by Kobe Steel, Japan) at a cylinder temperature of 270 to 280 °C, a rotation speed of 200 rpm, and an output rate of 38 kg / h. The strands were subsequently cooled in a water tank, stretched, and pelletized in a pelletizer. Subsequently, resin molded products were obtained by injection molding at a resin temperature of 270 to 280 °C and a mold temperature of 80 °C using a dumbbell-shaped ISO test piece mold with an injection molding machine (FANUC ROBOSHOT S-2000i 100A).The Charpy impact strength of the resin molded product was measured according to ISO 179-1. The fracture modes obtained by the Charpy impact test are listed in Table 2 along with the Charpy impact strength values, with complete fracture indicated by C and partial fracture indicated by P. The compositions of both the examples and the comparative examples exhibited a silver color with a metallic effect due to the aluminum glitter material and did not differ in appearance. [Table 1] Examples / Comparison examples Product name Model number Elongation at break (%) 300% tensile stress (MPa) Example 1 S. O E. (R) S1606 490 3,6 Example 2 Tuftec (R) Series M M1913 600 4,4 Example 3 Tuftec (R) Series M M1943 650 2,9 Example 4 Tuftec (R) Series H H1041 650 3,4 Example 5 Tuftec (R) Series H H1052 700 2,5 Comparison example 3 SOE (R) S1605 460 12,6 [Table 2] Examples Comparison examples 1 2 3 4 5 1 2 3 Glitter material (mass parts) 2 2 2 2 2 2 - 2 Modifying agent (parts by mass) 3 3 3 3 3 - - 3 Charpy impact strength (KJ / M 2 ) 54,0 66,4 62,8 59,5 61,5 10,9 72,0 14,9 Fracture forms P P P P P C P C

[0030] From the results shown in Table 2 above, it was found that the impact resistance can be improved by using a hydrogenated styrene-based thermoplastic elastomer with predetermined physical properties as a modifying agent.

Claims

[1] Resin composition with metallic effect, which is a - thermoplastic resin containing polycarbonate, - a glitter material and - contains a hydrogenated styrene-based thermoplastic elastomer with a 300% tensile stress of more than 0 and less than 12.6 MPa. [2] The resin composition according to claim 1, wherein the 300% tensile stress of the hydrogenated styrene-based thermoplastic elastomer is at least 2.5 MPa and at most 4.4 MPa. [3] The resin composition according to claim 1 or 2, wherein the elongation at break of the hydrogenated styrene-based thermoplastic elastomer is more than 460%. [4] The resin composition according to any one of claims 1 to 3, wherein the glitter material contains an aluminum glitter material. [5] The resin composition according to any one of claims 1 to 4, wherein the amount of the hydrogenated styrene-based thermoplastic elastomer is 1 to 10 parts by mass based on 100 parts by mass of the thermoplastic resin. [6] An impact-resistant member comprising a molded product of the resin composition according to any one of claims 1 to 5. [7] The impact-resistant member according to claim 6, which is a member for automobile interiors.