Resin part for writing implement and writing implement provided with same

Abstract

The purpose of the present invention is to provide a resin part for a writing implement that utilizes a recycled polyolefin resin as a raw material and has certain physical properties. This resin part for a writing implement contains a recycled polyolefin resin composition, the recycled polyolefin resin composition containing 100 parts by mass of a recycled polyolefin resin and 4-10 parts by mass of a compatibilizer. The recycled polyolefin resin contains a polypropylene resin and a polyethylene resin, and the impact strength of the recycled polyolefin resin composition is 3.00 kJ / m2 or more.

Description

Resin parts for writing instruments and writing instruments equipped with them

[0001] The present invention relates to a resin part for a writing instrument and a writing instrument equipped with the same.

[0002] In recent years, as an environmental measure, attention has been focused on the use of post-consumer materials, which are recycled by collecting used products from the market. Recycled polyolefin resin is widely used as this post-consumer material. Writing instruments are one type of resin product that contains many resin parts, and the following writing instruments are known as writing instruments made from polyolefin resin.

[0003] For example, Patent Document 1 discloses a felt-tip pen whose entire components are made of block-type polypropylene resin in order to ensure the strength of the press-fit and mating parts and the hardness of the entire shaft.

[0004] Furthermore, as a compatibilized polyolefin, Patent Document 2 discloses a composition comprising: a) one or more polyethylenes; b) one or more polypropylenes; c) one or more polyolefin elastomers; and d) a crystalline block composite comprising three components: i) a crystalline ethylene-based polymer; ii) a crystalline propylene-based polymer; and iii) a block copolymer having a crystalline ethylene-based block and a crystalline propylene block, wherein the composition of component i) is the same as that of the crystalline ethylene-based block of the block copolymer, and the composition of component ii) is the same as that of the crystalline propylene block of the block copolymer.

[0005] JP 2000-025381 A JP 2019-116638 A

[0006] Recycled polyolefin resin as a post-consumer material is a mixture of various polyolefin resins, containing polypropylene (PP) and polyethylene (PE) in various proportions. Therefore, when recycled polyolefin resin is used as a raw material, it is expected to be difficult to obtain resin parts for writing instruments with consistent physical properties.

[0007] Therefore, an object of the present invention is to provide resin parts for writing instruments that use recycled polyolefin resin as a raw material and have certain physical properties.

[0008] In this study, we investigated a compatibilizer that would make PP and PE compatible, based on the idea that the variation in physical properties of recycled polyolefin resins is due to the incompatibility of PP and PE. We investigated a method for improving the impact strength of recycled polyolefin resin compositions containing a certain amount of compatibilizer. ２ It has been found that by doing the above, it is possible to satisfy the performance requirements for a resin part for a writing instrument.

[0009] The present invention achieves the above object by the following means.

[0010] Aspect 1: A recycled polyolefin resin composition comprising: 100 parts by mass of recycled polyolefin resin; and 4 to 10 parts by mass of a compatibilizer; The recycled polyolefin resin comprises a polypropylene resin and a polyethylene resin; and the recycled polyolefin resin composition has an impact strength of 3.00 kJ / m ２ A resin part for a writing instrument as described above. Aspect 2: The resin part for a writing instrument according to Aspect 1, wherein the compatibilizer comprises an α-olefin copolymer. Aspect 3: The resin part for a writing instrument according to Aspect 1 or 2, wherein the content of the polypropylene resin is 1 to 10 times the content of the polyethylene resin. Aspect 4: A writing instrument comprising the resin part for a writing instrument according to any one of Aspects 1 to 3.

[0011] According to the resin part for a writing instrument of the present invention, a resin part for a writing instrument having certain physical properties can be provided by using recycled polyolefin resin as a raw material.

[0012] Fig. 1 is a schematic diagram for explaining a resin part for a writing instrument of the present invention. Fig. 2 is a schematic diagram for explaining a writing instrument in the present invention. Fig. 3 is a schematic diagram for explaining a clip bending test in the present invention. Fig. 4 is a schematic diagram for explaining an orientation bending test in the present invention.

[0013] Hereinafter, an embodiment of the present invention will be described in detail. Note that the present invention is not limited to the following embodiment, and various modifications can be made within the scope of the gist of the present invention. In addition, in the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted.

[0014] <<Resin Part for Writing Instrument>> The resin part for a writing instrument of the present invention comprises a recycled polyolefin resin composition, wherein the recycled polyolefin resin composition comprises 100 parts by mass of recycled polyolefin resin and 4 to 10 parts by mass of a compatibilizer, the recycled polyolefin resin comprises a polypropylene resin and a polyethylene resin, and the recycled polyolefin resin composition has an impact strength of 3.00 kJ / m ２ That's all.

[0015] According to the resin part for a writing instrument of the present invention, a resin part for a writing instrument having certain physical properties can be provided by using recycled polyolefin resin as a raw material.

[0016] In recycled polyolefin resin compositions containing a predetermined amount of compatibilizer, the polypropylene resin and polyethylene resin contained in the recycled polyolefin resin are compatible with each other, thereby preventing a significant decrease in impact strength. ２ By defining it as above, it can also be applied to resin parts for writing implements, particularly clip parts, which are movable and therefore require mechanical strength and flexibility.

[0017] FIG. 1 is a schematic diagram showing one embodiment of the resin part for a writing instrument of the present invention, but the present invention is not limited to this.

[0018] The resin part 100 for a writing instrument shown in FIG. 1 contains a recycled polyolefin resin composition, and the impact strength of the recycled polyolefin resin composition is 3.00 kJ / m ２ That's all.

[0019] The resin part for a writing instrument of the present invention is not particularly limited, but is preferably a clip part.

[0020] FIG. 2 is a schematic diagram showing one embodiment of a writing implement, but is not limited to this embodiment.

[0021] 2 has, as resin parts, for example, a clip portion 11, a shaft portion 12, and a knock bar portion 13. The resin parts for a writing instrument of the present invention are not particularly limited, but can be used as resin parts of the writing instrument 10, and may be the clip portion 11, the shaft portion 12, and / or the knock bar portion 13, with the clip portion 11 being preferred.

[0022] <Configuration of Recycled Polyolefin Resin Composition> In the resin part for a writing instrument of the present invention, the recycled polyolefin resin composition contains a recycled polyolefin resin and a compatibilizer, and may contain other additives as needed.

[0023] <Recycled Polyolefin Resin> Recycled polyolefin resins include polypropylene resins and polyethylene resins.

[0024] In the present invention, the recycled polyolefin resin is not particularly limited, but from the viewpoint of realizing sustainable development, it is preferable to use a polyolefin resin recovered from waste.

[0025] The polyolefin resin recovered from waste is preferably derived from, for example, post-consumer or pre-consumer materials. Post-consumer materials are defined in JIS Q14021:2000 as materials discarded from households or from commercial, industrial, and other end-user facilities that produce products that can no longer be used for their intended purposes. Pre-consumer materials are defined in JIS Q14021:2000 as materials removed from the waste stream during manufacturing processes.

[0026] (Polypropylene Resin) The polypropylene resin is not particularly limited, but examples thereof include homopolypropylene, random polypropylene, block polypropylene, etc. The polypropylene resin is not particularly limited, but one type may be used alone, or two or more types may be used in combination. When two or more types of polypropylene resins are used in combination, the content of the polypropylene resin is the sum of the respective contents.

[0027] As the homopolypropylene, for example, a polymer of a propylene monomer can be used.

[0028] Examples of random polypropylene include random copolymers of propylene and ethylene, and random copolymers of propylene and an α-olefin having 4 to 20 carbon atoms.

[0029] Examples of the α-olefins include 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Of these, α-olefins having 2 to 8 carbon atoms are preferred, and specifically, ethylene, 1-butene, 3-methyl-1-butene, 1-hexene, and 4-methyl-1-pentene are preferred. One type of α-olefin may be used alone, or two or more types may be used in combination.

[0030] The block polypropylene may be, for example, a polypropylene in which polyethylene is dispersed in homopolypropylene to form a sea-island morphology, but is not limited to this. The block polypropylene may also be, but is not particularly limited to, a mixture of a propylene homopolymer and a propylene-ethylene copolymer.

[0031] (Polyethylene Resin) Examples of polyethylene resins include, but are not limited to, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ultra-high molecular weight polyethylene. Furthermore, the polyethylene resin may include, but is not limited to, both an ethylene homopolymer and a copolymer of ethylene and another monomer copolymerizable with the ethylene (e.g., a binary or tertiary copolymer). The bonding form of the copolymer is, but is not limited to, either random or block. The polyethylene resin is, but is not limited to, one type alone, or two or more types in combination. When two or more types of polyethylene resins are used in combination, the content of the polyethylene resins is the sum of the respective contents.

[0032] Other monomers copolymerizable with ethylene include, but are not limited to, α-olefin compounds, vinyl compounds, non-conjugated polyene compounds, etc. One type of other monomer may be used alone, or two or more types may be used in combination. Examples of the α-olefin compounds include α-olefin compounds having 3 to 20 carbon atoms, such as propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, and 1-tetradecene. Examples of the vinyl compounds include vinylcyclohexene, styrene, and derivatives thereof. Examples of the non-conjugated polyene compounds include 1,5-hexadiene and 1,7-octadiene.

[0033] (Composition of recycled polyolefin resin) The total content of polypropylene resin and polyethylene resin in the recycled olefin resin may be, for example, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, or 100% by mass or less, 99% by mass or less, 95% by mass or less, or 90% by mass or less, where 100% by mass is the total recycled polyolefin resin.

[0034] In the resin part for a writing instrument of the present invention, the content of polypropylene resin is not particularly limited, but may be, for example, 1 time or more, 2 times or more, 3 times or more, 4 times or more, or 5 times or more the content of polyethylene resin, or 10 times or less, or 9 times or less, and is preferably 1 to 10 times the content of polyethylene resin.

[0035] The content of polypropylene resin is not particularly limited, but may be 50 parts by mass or more, 60 parts by mass or more, 70 parts by mass or more, 80 parts by mass or more, or 90 parts by mass or more, or 90 parts by mass or less, 80 parts by mass or less, or 70 parts by mass or less, per 100 parts by mass of recycled polyolefin resin.

[0036] The content of polyethylene resin is not particularly limited, but may be 6 parts by mass or more, 8 parts by mass or more, or 10 parts by mass or more, or 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, or 10 parts by mass or less, per 100 parts by mass of recycled polyolefin resin.

[0037] Recycled polyolefin resins, particularly recycled polyolefin resins recovered from waste, may contain other resins and impurities in addition to the polypropylene resin and polyethylene resin as the main components. The total content of the other resins and impurities other than the main components may be 0% by mass or more, 1% by mass or more, or 5% by mass or more, or 40% by mass or less, 30% by mass or less, 20% by mass or less, or 10% by mass or less, based on 100% by mass of the entire recycled polyolefin resin. The other resins and impurities other than the main components are not particularly limited, but it is preferable that they are not included.

[0038] Resins other than the main component that can be contained in the recycled polyolefin resin are not particularly limited, but examples include general-purpose resins other than polypropylene resin and polyethylene resin, engineering plastics, super engineering plastics, and the like.

[0039] <Compatibilizer> Examples of compatibilizers include, but are not limited to, polyphenylene sulfide resin, cyclic olefin copolymer, α-olefin copolymer, hydrogenated styrene butadiene rubber, etc. The compatibilizer is not particularly limited, but α-olefin copolymer is preferred from the viewpoint of improving the compatibility between polypropylene resin and polyethylene resin. By including the above-mentioned compatibilizer, it is possible to suppress the deterioration of the physical properties of the recycled polyolefin resin compared to, for example, polyolefin resin as a virgin resin. The compatibilizer is not particularly limited, but only one type may be used alone, or two or more types may be used in combination. When two or more types of compatibilizers are used in combination, the content of the compatibilizers is the sum of the respective contents.

[0040] The α-olefin copolymer is a copolymer containing an α-olefin having 3 to 20 carbon atoms, and may be, for example, a copolymer of ethylene and an α-olefin, a copolymer of propylene (1-propylene or 2-propylene) and an α-olefin, or a copolymer of butene (1-butene or 2-butene) and an α-olefin, or more specifically, a copolymer of 1-octene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-decene with ethylene or propylene. For details of the α-olefins, please refer to the description of "(Polypropylene Resin)" above.

[0041] Specific examples of α-olefin copolymers that can be used include TAFMER (A-0550S, A-4090S, DF640, DF810, MP0610, etc.) manufactured by Mitsui Chemicals, and ABSOTMER (EP-1001, EP-1013, etc.) manufactured by Mitsui Chemicals, but are not limited to these.

[0042] (Compatibilizer Content) In the resin part for a writing instrument of the present invention, the content of the compatibilizer contained in the recycled polyolefin resin composition is 4 to 10 parts by mass per 100 parts by mass of the recycled polyolefin resin. The content of the compatibilizer may be 4 parts by mass or more, or 5 parts by mass or more, or may be 10 parts by mass or less, 9 parts by mass or less, 8 parts by mass or less, 7 parts by mass or less, 6 parts by mass or less, or 5 parts by mass or less.

[0043] The total content of the recycled polyolefin resin and the compatibilizer in the recycled polyolefin resin composition may be, for example, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, or 100% by mass or less, 99% by mass or less, 95% by mass or less, or 90% by mass or less, where the entire recycled polyolefin resin composition is 100% by mass.

[0044] <Other Additives> The recycled polyolefin resin composition may contain known additives such as antioxidants, slip agents, neutralizing agents, light stabilizers, antistatic agents, and pigments, as needed.

[0045] (Antioxidant) The antioxidant is not particularly limited, but examples thereof include phenol-based antioxidants, phenol-phosphorus-based antioxidants, and phosphorus-based antioxidants.

[0046] Examples of phenolic antioxidants include, but are not limited to, 2,6-di-t-butyl-4-methylphenol, n-octadecyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate, and tetrakis(methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate))methane.

[0047] Examples of phenol-phosphorus antioxidants include, but are not limited to, 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphepine.

[0048] Examples of phosphorus-based antioxidants include, but are not limited to, tetrakis(2,4-di-t-butylphenyl)-4,4′-biphenylene-di-phosphonite, tris(2,4-di-t-butylphenyl)phosphite, and cyclic neopentanetetraylbis(2,4-t-butylphenylphosphite).

[0049] (Slip Agent, Neutralizing Agent) The slip agent or neutralizing agent is not particularly limited, but examples thereof include aliphatic hydrocarbons, higher fatty acids, higher fatty acid metal salts, fatty acid esters of alcohols, waxes, higher fatty acid amides, silicone oils, rosin, etc. Examples of the slip agent or neutralizing agent include, but are not limited to, stearates, specifically calcium stearate, magnesium stearate, zinc stearate, etc.

[0050] (Light Resistance Stabilizer) The light resistance stabilizer is not particularly limited, but examples thereof include benzotriazole-based light resistance stabilizers and hindered amine-based light resistance stabilizers.

[0051] Examples of the benzotriazole-based light stabilizer include, but are not limited to, 2-(5-methyl-2-hydroxyphenyl)benzotriazole and 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole.

[0052] Examples of the hindered amine light resistance stabilizer include, but are not limited to, bis(2,2,6,6-tetramethyl-4-piperidine) sebacate and poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}].

[0053] (Antistatic Agent) The antistatic agent is not particularly limited, but examples thereof include aluminosilicate, kaolin, clay, natural silica, synthetic silica, silicates, talc, diatomaceous earth, glycerin fatty acid esters, and the like.

[0054] (Pigment) The pigment is not particularly limited, but examples thereof include inorganic pigments, organic pigments, etc. Examples of inorganic pigments include, but are not limited to, titanium oxide, carbon black, and iron oxide pigments. Examples of organic pigments include, but are not limited to, azo pigments, phthalocyanine pigments, and condensed polycyclic pigments.

[0055] The recycled polyolefin resin composition can be produced by applying known methods (e.g., dry blending, masterbatch, extrusion kneading, melt kneading, etc.). For example, the recycled polyolefin resin composition can be easily produced by melt kneading raw materials containing the above-mentioned various components.

[0056] <Physical properties of recycled polyolefin resin composition> In the resin part for a writing instrument of the present invention, the impact strength of the recycled polyolefin resin composition is 3.00 kJ / m ２ The impact strength is 3.00 kJ / m or more. ２ Above, 3.20kJ / m ２ or more, or 3.40 kJ / m ２ or more, 30.0 kJ / m ２ Below, 20.0kJ / m ２ Below, 10.0kJ / m ２ or less, or 5.00 kJ / m ２ It may be the following:

[0057] The impact strength of the recycled polyolefin resin composition can be determined by a Charpy impact test in accordance with JIS K7111-1:2012. The test specimens used for the Charpy impact test can be obtained by injection molding the recycled polyolefin resin composition (melt temperature 200°C, mold temperature 30°C, filling speed 50 mm / s) to a length of 80 mm, width 10 mm, and thickness 4 mm. The test specimens used for the Charpy impact strength test were notched using notch type A with a width of 8 mm. The impact direction for the Charpy impact test was edgewise.

[0058] <Molding of Resin Parts for Writing Instruments> Resin parts for writing instruments can be molded from recycled polyolefin resin compositions by applying known methods. For example, resin parts for writing instruments can be easily molded by injection molding recycled polyolefin resins.

[0059] <Writing Instrument> The writing instrument of the present invention includes the above-described resin part for a writing instrument.

[0060] The writing implement of the present invention uses a recycled polyolefin resin composition as a raw material and can have certain physical properties.

[0061] 2, the writing instrument 10 has, as resin parts, for example, a clip portion 11, a shaft portion 12, and a knock bar portion 13. The writing instrument of the present invention may be provided with the above-mentioned resin parts for a writing instrument in the clip portion 11, the shaft portion 12, and / or the knock bar portion 13. In particular, it is preferable that the clip portion 11 is provided with the resin parts.

[0062] The writing implement of the present invention is not particularly limited, but may be a ballpoint pen or a marking pen.

[0063] (Physical Properties of Writing Instruments: Clip Bending Test) Writing instruments, particularly clip parts, are sometimes required to have good flexibility, although this is not particularly limited. The flexibility of a writing instrument can be determined, for example, by a clip bending test.

[0064] FIG. 3 is a schematic diagram showing one embodiment of the clip bending test, but is not limited to this case.

[0065] First, as shown in FIG. 3A, the end 11a of the clip is lifted and bent away from the axis of the clip. Then, as shown in FIG. 3C, the end 11a of the clip is bent approximately 180° so as to approach the connection 11b between the clip and the clip inner tube. FIG. 3B shows the clip bending test in progress. As shown in FIG. 3C, if the clip does not break upon completion of the clip bending test, it can be determined to have passed. For example, if the above test is performed five times and not a single break occurs, i.e., all five times pass, it can be determined that the clip has good flexibility.

[0066] The present disclosure will be described in more detail with reference to the following examples, but the scope of the present disclosure is not limited to these examples.

[0067] Example 1 Preparation of Recycled Polyolefin Resin Composition A1 Recycled polyolefin resin composition A1 was prepared by extrusion molding (melting temperature 200°C) of 90 parts by mass of polypropylene resin (recycled PP-1) as a post-consumer material, 10 parts by mass of polyethylene resin (recycled PE-1) as a post-consumer material, and α-olefin copolymer (Tafmer DF640 manufactured by Mitsui Chemicals) as a compatibilizer.

[0068] <Preparation of Resin Part B1 for Writing Instrument> The recycled polyolefin resin composition A1 was injection molded (melting temperature 200°C, mold temperature 30°C, filling speed 50 mm / s) to prepare a clip with an inner tube as shown in Figures 1 and 3 as a resin part B1 for a writing instrument.

[0069] <Charpy Impact Strength of Recycled Polyolefin Resin Composition A1> Charpy impact strength test specimens measuring 80 mm in length, 10 mm in width, and 4.0 mm in thickness were prepared using recycled polyolefin resin composition A1 by injection molding (melt temperature 200°C, mold temperature 30°C, filling speed 50 mm / s). The Charpy impact strength test specimens were notched using notch type A with a width of 8 mm. The Charpy impact strength was measured in accordance with JIS K7111:2012. The impact direction in the Charpy impact test was edgewise. The Charpy impact strength of recycled polyolefin resin composition A1 was measured five times, and the average values ​​are shown in Table 1.

[0070] Orientation Bending Test: Using the recycled polyolefin resin composition A1, a square plate type D2 test piece measuring 60 mm in length, 60 mm in width, and 2 mm in thickness according to JIS K7152-3:2006 was prepared by injection molding (melt temperature 200°C, mold temperature 30°C, filling speed 50 mm / s). Loads were applied parallel and perpendicular to the resin flow direction during molding, and the orientation bending test piece was bent 180° under the load to check for fracture. Specifically, as shown in FIG. 4, a load was applied to the orientation bending test piece 21 from a direction 21a parallel to the resin flow direction during molding, and the orientation bending test piece 21 was bent 180° under the load to check for fracture. Similarly, a load was applied from a direction 21b perpendicular to the resin flow direction during molding, and the orientation bending test piece 21 was bent 180° under the load to check for fracture. The orientation bending test was performed five times, and the results are shown in Table 1. The evaluation criteria are as follows: A: No breakage occurred in any of the five tests. B: Breakage occurred at least once in the five tests.

[0071] <Clip Bending Test> As shown in Figures 3(A) to 3(C), the clip end of the resin part B1 for a writing instrument was lifted and the end of the clip was bent 180 degrees to check for breakage. The clip bending test for the resin part B1 for a writing instrument was performed five times, and the results of the clip bending test for the resin part B1 for a writing instrument were as shown in Table 1. The evaluation criteria were as follows: A: No breakage occurred in any of the five tests. B: Breakage occurred one or more times in the five tests.

[0072] Example 2 Preparation of recycled polyolefin resin composition A2 and writing instrument resin part B2, and Charpy impact strength of recycled polyolefin resin composition A2 A recycled polyolefin resin composition A2 was prepared in the same manner as in Example 1, except that a polypropylene resin (recycled PP-2) and a polyethylene resin (recycled PE-2) different from the post-consumer materials used in Example 1 were used, and a writing instrument resin part B2 was produced using the same. The Charpy impact strength of the recycled polyolefin resin composition A2 was measured in the same manner as in Example 1 and was as shown in Table 1.

[0073] Comparative Examples 1 to 5 Preparation of Recycled Polyolefin Resin Compositions a1 to a5 and Writing Instrument Resin Parts b1 to b5, and Charpy Impact Strength of Recycled Polyolefin Resin Compositions a1 to a5 Recycled polyolefin resin compositions a1 to a5 were prepared in the same manner as in Example 1, except that the materials shown in Table 1 were used, and writing instrument resin parts b1 to b5 were used to prepare them. The Charpy impact strength of recycled polyolefin resin compositions a1 to a5 was measured in the same manner as in Example 1, and the measurement results are shown in Table 1.

[0074] <Clip Bending Test and Orientation Bending Test> The clip bending test and orientation bending test were carried out in the same manner as in Example 1, and the evaluation results were as shown in Table 1.

[0075]

[0076] The Charpy impact strength of the recycled polyolefin resin composition is 3.00 kJ / m ２If the above conditions are not met, it is difficult to use the composition as a writing implement, and in particular, the composition breaks in the clip bending test. ２ If the above conditions are not satisfied, even if the resin does not break in the orientation bending test, it will break in the clip bending test, and the results show that it is not suitable for use as a resin part for a writing instrument.

[0077] Although the details are unclear, it is speculated that in recycled polyolefin resin compositions containing a specified amount of compatibilizer, the polypropylene resin and polyethylene resin contained in the recycled polyolefin resin are compatible with each other, thereby preventing a significant decrease in impact strength. ２ By defining it as above, it is presumed that it can also be applied to resin parts for writing instruments, particularly clip parts, which are movable and therefore require mechanical strength and flexibility.

[0078] Although preferred embodiments of the resin part for a writing instrument and the writing instrument of the present invention have been described, those skilled in the art will understand that modifications can be made without departing from the scope of the claims.

[0079] REFERENCE SIGNS LIST 10 Writing implement 11 Clip portion 11a End portion of clip 11b Connection portion between clip and clip inner tube 12 Shaft portion 13 Knock bar portion 21 Test piece for orientation bending test 21a Parallel direction to resin flow direction during molding 21b Perpendicular direction to resin flow direction during molding 100 Resin part for writing implement

Claims

1. A recycled polyolefin resin composition comprising 100 parts by mass of recycled polyolefin resin and 4 to 10 parts by mass of a compatibilizer, wherein the recycled polyolefin resin comprises a polypropylene resin and a polyethylene resin, and the impact strength of the recycled polyolefin resin composition is 3.00 kJ / m ２ That's it for resin parts for writing instruments.

2. The resin part for a writing instrument according to claim 1, wherein the compatibilizer comprises an alpha-olefin copolymer.

3. A resin part for a writing instrument according to claim 1 or 2, wherein the content of the polypropylene resin is 1 to 10 times the content of the polyethylene resin.

4. A writing instrument comprising the resin part for a writing instrument according to any one of claims 1 to 3.

Images