Resin composition, razor handle, and razor

Abstract

To provide a resin composition or the like for a razor handle, capable of maintaining full functionality of a razor, especially a swing type razor while reducing a waste generation amount, CO2 gas emissions, and an environmental load.SOLUTION: Provided is a resin composition used for forming a body of a razor handle provided with a swing mechanism which supports a razor head and has a plate spring. In the resin composition, a first additive containing a plant-derived component and a second additive containing a biodegradable component are blended in a matrix resin, the content ratio of the second additive is 1 to 10 mass%, the melt flow rate is 4 to 6 g / 10 min, and the flexural modulus is 2000 to 2400 MPa.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition for forming the body of a razor handle, a razor handle, and a razor. [Background technology]

[0002] In a typical handheld sharp tool, a razor is primarily composed of a razor head and a handle (also called a holder), and the handle body is usually made of a hard resin, such as high impact polystyrene (HIPS), acrylonitrile-butadiene-styrene copolymer (ABS) resin, or polypropylene (PP), from the viewpoints of workability, grip, strength, etc. (See, for example, Patent Document 1.) After use, this handle body is collected and recycled as a plastic resource, or may be discarded as plastic waste. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-24456 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the "3Rs" have been advocated, a collective term for the three Rs: Reduce, which means using things carefully and reducing waste; Reuse, which means repeatedly using usable items; and Recycle, which means using waste again as a resource.

[0005] Furthermore, the Sustainable Development Goals (SDGs) recently adopted at the United Nations Summit include 17 goals, each with around 10 specific targets (169 in total). One of these goals, "Responsible Consumption and Production," calls for ensuring sustainable production and consumption patterns, and calls for a significant reduction in waste generation. Another goal, "Take concrete action to combat climate change," calls for urgent measures to combat climate change and its effects, and there is an urgent need to curb CO2 gas emissions in order to prevent global warming, which is said to be a major cause of climate change.

[0006] Achieving these goals is a global priority, regardless of the field, and the development of products that meet these needs is being promoted in the razor field as well. A common method for achieving this is, for example, adding plant-derived or biodegradable ingredients to the hard resin that forms the handle. However, if the biodegradable ingredients are added in too small a proportion, biodegradation may not occur effectively, while if the biodegradable ingredients are added in too large a proportion, biodegradation may progress quickly, resulting in insufficient durability as a razor. Furthermore, as described in Patent Document 1, in the case of a swivel razor with a handle equipped with a leaf spring to enable the swivel of the razor head, depending on the proportion of biodegradable ingredients, the leaf spring may become more brittle than the other components. This may result in the leaf spring's performance not being maintained, raising concerns that the swivel razor's functionality may not be fully realized and maintained.

[0007] Therefore, the present disclosure has been made in consideration of these circumstances, and aims to provide a resin composition for forming the body of a razor handle that can fully maintain the functionality of a razor, particularly an oscillating razor, while reducing the amount of waste generated, CO2 gas emissions, and the burden on the environment, a razor handle having such a body, and a razor equipped with such a handle. [Means for solving the problem]

[0008] In order to solve the above problems, the present disclosure provides the following configuration. Note that in the following description, reference numerals and the like in the drawings may be added in parentheses to facilitate understanding of the present disclosure, but the components of the present disclosure are not limited to these specific configurations and should be interpreted broadly to the extent that a person skilled in the art can technically understand them.

[0009] [1] An example of a resin composition according to the present disclosure is for forming a main body (10) of a handle (1) of a razor (100) on which a razor head (2) is supported and which is provided with a swing mechanism (3) having a leaf spring (32). The resin composition contains a base (matrix) resin blended with a first additive containing a plant-derived component and a second additive containing a biodegradable component. The resin composition contains 1 to 10% by mass of the second additive. The resin composition has a melt flow rate of 4 to 6 g / 10 min and a flexural modulus of 2000 to 2400 MPa.

[0010] Here, the "plant-derived component" included in the "first specific component" is biomass derived from organic components produced from starch-containing plants such as corn, sugarcane, and potato. The "biodegradable component" included in the "second specific component" includes at least the "degradable polymer composition" described in Japanese Patent No. 2961138. The content of Japanese Patent No. 2961138 is incorporated herein by reference. This second specific component is decomposed into harmless products by the action of sunlight, ultraviolet light, heat, water, oxygen, enzymes, and / or microorganisms, and is itself biodegradable, for example, by oxidative decomposition. Furthermore, the "melt flow rate" is a value measured under test conditions of 200°C and 5 kg according to a test method conforming to ISO 1133-1. The "flexural modulus" here is a value measured under test conditions of 2 mm / min according to a test method conforming to ISO 178.

[0011] According to this configuration, the resin composition used to form the body 10 of the handle 1 of the razor 100 contains a first additive containing a plant-derived component, thereby reducing the amount of petroleum- or coal-derived resin used and, in turn, CO2 gas emissions. Furthermore, because the resin composition contains a second additive containing a biodegradable component, when the handle 1 is discarded, for example, in soil, a chain reaction occurs due to the oxidative decomposition of the biodegradable component upon exposure to the external environment, resulting in the polymer molecules in the resin composition being broken down into smaller molecules, and the body 10 of the handle 1 is ultimately biodegraded into CO2 and water.

[0012] Furthermore, since the content of the second additive in the resin composition is 1 to 10% by mass, the biodegradable components contained in the second additive are uniformly dispersed in the base resin, resulting in the body (10) of the handle (1) being easily degraded uniformly and preventing excessive shortening of its service life. Furthermore, since the melt flow rate of the resin composition is 4 to 6 g / 10 min, sufficient fluidity is ensured during molding. Furthermore, since the flexural modulus of the resin composition is 2000 to 2400 MPa, excellent spring properties are exhibited in the leaf spring (32) in the swing mechanism (3) of the razor head (2) provided in the body (10) of the handle (1).

[0013] [2] In the above configuration, the base resin may primarily contain recycled resin. This allows for the formation of a handle (1) and a razor (100) with a high utilization rate of recycled materials and a low environmental impact. Furthermore, the recycled resin content in the base resin may be 90% by mass or more. This significantly reduces the material cost of the base resin and sufficiently increases the utilization rate of recycled materials.

[0014] [3] In the above configuration, the base resin may primarily contain a styrene-based resin and / or a propylene-based resin. This allows for the formation of a body 10 of the handle 1 that is excellent in heat resistance, impact resistance, rigidity, moldability, dimensional stability, acid resistance, alkali resistance, and the like. The base resin may also contain 80% by mass or more of the styrene-based resin and / or the propylene-based resin. This makes it easier for the body 10 of the handle 1 to exhibit the various excellent properties of the styrene-based resin and / or the propylene-based resin.

[0015] [4] In the above configuration, the total content of the first and second additives in the resin composition may be 20% by mass or less, which reduces material costs and prevents deterioration in the moldability of the main body 10 of the handle 1 and the physical properties of the base resin.

[0016] [5] More specifically, the content of the first additive in the resin composition may be 1 to 20% by mass. By adjusting the content in this manner, a sufficient plant-derived effect is imparted to the resin composition for forming the body 10 of the handle 1, and the moldability of the body 10 of the handle 1 and the physical properties of the base resin are easily maintained.

[0017] [6] Furthermore, one example of the handle (1) of the razor (100) according to the present disclosure has a main body (10) formed by curing the resin composition described in any one of [1] to [5] above.

[0018] [7] Furthermore, an example of a razor (100) according to the present disclosure includes a handle (1) of the razor (100) described in [6] above, and a razor head (2) supported by a oscillating mechanism (3) having a leaf spring (32) in the handle (1). [Effects of the Invention]

[0019] The resin composition, razor handle (1), and razor (100) according to the present disclosure contain a base resin that is blended with a first additive containing a plant-derived component and a second additive containing a biodegradable component. This allows for reduced CO2 gas emissions through the use of the plant-derived component, and reduced waste generation through the use of the biodegradable component. As a result, the resin composition, razor handle (1), and razor (100) according to the present disclosure promote the 3Rs and SDGs and effectively contribute to achieving these goals. Furthermore, the resin composition according to the present disclosure contains 1 to 10% by mass of the second additive, has a melt flow rate of 4 to 6 g / 10 min, and a flexural modulus of 2000 to 2400 MPa. This allows for effective biodegradation of the razor handle (1), while preventing the biodegradation from progressing too quickly, resulting in sufficient durability for the razor (100). Furthermore, the leaf spring (32) is prevented from becoming excessively more brittle than the other components, and the function of the oscillating razor (100) can be maintained sufficiently. [Brief explanation of the drawings]

[0020] [Figure 1A] 1 is an overall perspective view showing the schematic configuration of an example of a razor according to an embodiment of the present disclosure, viewed from the front and side of the handle. FIG. [Figure 1B] 1 is an overall perspective view of a schematic configuration of an example of a razor according to an embodiment of the present disclosure, viewed from the rear and side of the handle. FIG. [Figure 2A] FIG. 2 is a plan view of the razor shown in FIG. [Figure 2B] FIG. 2 is a bottom view of the razor shown in FIG. [Figure 2C] FIG. 2 is a side cross-sectional view of the razor shown in FIG. [Figure 3] 1 is a photograph showing a state in which molded articles of Examples and Comparative Examples are being prepared for an accelerated deterioration test by ultraviolet irradiation. [Figure 4A] 1 is a graph showing the FT-IR absorption spectrum of molded article S of Example 1 in an accelerated deterioration test by ultraviolet irradiation. [Figure 4B]1 is a graph showing the FT-IR absorption spectrum of molded article S of Example 2 in an accelerated deterioration test by ultraviolet irradiation. [Figure 4C] 1 is a graph showing the FT-IR absorption spectrum of the molded article S of Comparative Example 1 in an accelerated deterioration test by ultraviolet irradiation. [Figure 5A] 10 is a photograph showing a state in which a destructive test is being performed on molded articles of Examples and Comparative Examples after completion of an accelerated deterioration test using ultraviolet light irradiation. [Figure 5B] 10 is a photograph showing a state in which a destructive test is being performed on molded articles of Examples and Comparative Examples after completion of an accelerated deterioration test using ultraviolet light irradiation. [Figure 6] 10 is a graph conceptually showing the change in the degree of deterioration of the main body of the steering wheel relative to the content ratio of the second additive in the resin composition. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment according to an example of the present disclosure will be described with reference to the drawings and the like. However, the embodiment described below is merely an example, and is not intended to exclude various modifications or applications of technologies not explicitly described below. In other words, the example of the present disclosure can be implemented with various modifications within the scope of its spirit. Furthermore, the drawings below are schematic and do not necessarily correspond to actual dimensions, ratios, etc. Furthermore, the embodiments described below are only some embodiments of the present disclosure, and are not all embodiments. Furthermore, other embodiments that can be obtained by a person skilled in the art based on the embodiments of the present disclosure without requiring creative acts are all included in the scope of protection of the present disclosure.

[0022] [Example of razor and handle configuration] 1A and 1B are perspective views showing a schematic configuration of an example of a razor according to an embodiment of the present disclosure, with Fig. 1A being an overall perspective view of the razor as viewed from the front and side of the handle, and Fig. 1B being an overall perspective view of the razor as viewed from the back and side of the handle, and Figs. 2A to 2C being a plan view, a bottom view, and a side cross-sectional view, respectively, of the razor shown in Fig. 1.

[0023] The razor 100 is a swiveling razor having a handle 1 and a razor head 2 attached thereto. The handle 1 is configured so that the user can grip it, and is made of a relatively hard resin. To improve the user's grip and ease of handling, the handle 1 is assembled to a main body 10. The main body 10 is made of a relatively hard resin, and a surface member 20 is made of a suitable relatively soft resin, such as an elastomer resin. Although the main body 10 of the handle 1 does not have a clear boundary, it can be divided into a grip portion 11 extending from its center to its lower end, and a head portion 12 located above the grip portion 11 on the main body 10. The main body 10 of the handle 1 further has a swiveling mechanism 3 including support arms 31, 31 and a leaf spring 32 extending from the head portion 12 toward the razor head 2. The razor head 2 is attached to the front side of the head portion 12 of the main body 10 via the swiveling mechanism 3, and is supported so that the razor head 2 is biased forward and tilts mainly in the vertical direction. The razor head 2 has a blade support portion 21 to which a plurality of blades 22 are attached.

[0024] [Resin composition for forming the body of the razor handle] The resin composition for forming the main body 10 of the handle 1 of the razor 100 according to one embodiment of the present disclosure comprises a base (matrix) resin blended with a first additive containing a plant-derived component and a second additive having a biodegradable component. The resin composition has a melt flow rate (MFR) of 4 to 6 g / 10 min and a flexural modulus of 2000 to 2400 MPa. The total content of the first and second additives in the resin composition is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less.

[0025] <(A) Base resin> The base resin in the resin composition used to form the main body 10 of the handle 1 may be virgin, recycled, or a mixture thereof, but it is more preferable to use a resin that primarily contains recycled resin. In this disclosure, "recycled resin" includes resins reused as plastic materials through material recycling (melting waste plastics and pelletizing them) and resins formed from raw materials that have been chemically recycled (chemically treating waste plastics to produce chemical raw materials) (see, for example, "Basic Knowledge of Plastic Recycling 2021" by the Plastic Waste Management Institute). Furthermore, it is preferable to use resins that are pre-consumer materials conforming to JIS Q14021 and resins that are post-consumer materials conforming to JIS Q14021 as material recycled materials. Furthermore, the recycled resin content of the base resin is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 95% by mass or more.

[0026] The type of base resin is not particularly limited as long as it can be a resin material that can produce a relatively hard molded product for the main body 10 of the handle 1. Furthermore, the recycled resin and the base resin may be the same or different. More specifically, it is more preferable to use a resin that primarily contains a styrene-based resin and / or a propylene-based resin. Examples of "styrene-based resins" include general-purpose polystyrene (GPPS), high-impact polystyrene (HIPS), syndiotactic polystyrene (SPS), and resin compositions containing one or more of these as the main component. Examples of "propylene-based resins" include homopolypropylene, block copolymers of propylene, ethylene, and an appropriate olefin (block polypropylene), random copolymers of propylene, ethylene, and an appropriate olefin (random polypropylene), and resin compositions containing one or more of these as the main component. Furthermore, the content of the styrene-based resin and / or propylene-based resin in the base resin is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more.

[0027] <(B) First additive> As described above, the plant-derived component contained in the first additive in the resin composition used to form the body 10 of the handle 1 includes at least biomass derived from organic components produced from starch-containing plants such as corn, sugarcane, and potato. The content of the first additive in the resin composition used to form the body 10 of the handle 1 is preferably 1 to 20% by mass, more preferably 1 to 10% by mass, and even more preferably 1 to 5% by mass. A specific example of an available first additive is Bio-Nobon (trademark: hereinafter, the term "trademark" will be omitted in this specification and claims).

[0028] <(C) Second Additive> As mentioned above, the biodegradable component contained in the second additive in the resin composition for forming the main body 10 of the handle 1 includes at least the "degradable polymer composition" described in Japanese Patent No. 2961138. This biodegradable component is decomposed into harmless products by the action of sunlight, ultraviolet light, heat, water, oxygen, enzymes, and / or microorganisms, and is itself biodegradable, for example, by oxidative decomposition, and is composed of the following five components: That is, the second specific component is a polymer composition and includes the following components (i) to (v):

[0029] (i) a thermoplastic polymer component formed from long chain carbon-carbon bonds (ii) a directly biodegradable component that is mixed into the thermoplastic polymer component and is decomposed and removed by the action of sunlight, ultraviolet light, heat, water, oxygen, enzymes, and / or microorganisms, thereby increasing the exposure area of ​​the carbon-carbon bonds of the thermoplastic polymer component to the environment; (iii) an oxidizable component selected from fatty acids, fatty acid esters, natural fats, natural or synthetic rubbers, or mixtures thereof, for reacting with and severing exposed carbon-carbon bonds in the thermoplastic polymer component, thereby degrading the thermoplastic polymer component. (iv) a transition metal component that is compatible with the polymer composition and initiates the reaction of the oxidizable component with the thermoplastic polymer component. (v) a non-metallic stabilizing component comprising a hindered phenol that delays the onset of the degradation process of the thermoplastic polymer component;

[0030] When a handle 1 formed from a resin composition containing the second additive is discarded, for example, in soil and exposed to external environments (sunlight, ultraviolet light, heat, water, oxygen, etc.), the biodegradable components of the second additive begin to undergo oxidative decomposition. During this process, C-H bonds in the polymer molecules contained in the biodegradable components are cleaved to generate alkyl radicals (R·), which then react with atmospheric O2. Furthermore, the peroxy radicals (ROO·) generated in this reaction react with the polymer molecules of the resin composition, cleaving C-H bonds within the same or other molecular chains to generate new alkyl radicals (R·) and hydroperoxides (ROOH). Because the dissociation energy of the O--O bond is low, these hydroperoxides (ROOH) readily dissociate into alkoxy radicals (RO·) and hydroxyl radicals (OH·), increasing the radical concentration in the resin composition over time.

[0031] The alkoxy radicals (RO·) generated by these chain reactions easily induce beta-cleavage of polymer molecules, severing the main chain of the polymer molecules and promoting the degradation of their molecular weight and physical properties. Eventually, the body 10 of the handle 1 breaks down into fine particles (microplastics). This process also produces low-molecular-weight carbonyl compounds (aldehydes, ketones, carboxylic acids, esters, peresters, etc.), whose identification and quantification allow us to assess the degree of oxidative decomposition of the polymer molecules. Microorganisms, such as white-rot fungi, present in soil, absorb and digest these finely divided components, ultimately biodegrading the body 10 of the handle 1 into CO₂ and water, and reducing it to nature.

[0032] The content of the second additive in the resin composition for forming the main body 10 of the handle 1 is 1 to 10% by mass, preferably 1 to 5% by mass, and more preferably 1 to 2% by mass. A specific example of an available second additive is Degranovon (trademark: hereinafter, the term "trademark" will be omitted in this specification and claims).

[0033] [Action and effect] The resin composition, razor handle 1, and razor 100 according to the present disclosure having the above-described configurations provide the following advantageous effects.

[0034] (1) The resin composition used to form the body 10 of the handle 1 of the razor 100 contains a first additive containing a plant-derived component, which allows for a reduction in the amount of petroleum- or coal-derived resin used. Therefore, compared to when the base resin of the body 10 of the handle 1 is made solely of petroleum- or coal-derived resin, the amount of CO2 gas emitted upon incineration can be reduced. Thus, the "first additive" is a functional additive (master batch) that imparts a plant-derived effect to the resin composition used to form the body 10 of the handle 1. In other words, it functions as an agent for suppressing CO2 gas emissions from the body 10 of the handle 1.

[0035] (2) By including a second additive containing a biodegradable component in the resin composition used to form the body 10 of the handle 1 of the razor 100, the body 10 of the handle 1 is ultimately biodegraded into CO2 and water, and therefore does not become plastic waste (waste), thereby reducing the amount of waste generated. In this way, the "second specific component" is a functional additive (masterbatch) that imparts biodegradability to the resin composition used to form the body 10 of the handle 1; in other words, it functions as an agent that promotes the natural decomposition of the body 10 of the handle 1.

[0036] (3) For these reasons, the resin composition, the handle 1 of the razor 100, and the razor 100 according to the present disclosure can reduce CO2 gas emissions and waste generation, thereby promoting the 3Rs and SDGs and effectively contributing to achieving those goals.

[0037] (4) Furthermore, because the content of the second additive (e.g., DegraNobon) in the resin composition used to form the body 10 of the handle 1 is 1% by mass or more, the biodegradable components contained in the second additive are easily dispersed uniformly throughout the base resin (preventing uneven distribution), resulting in the body 10 of the handle 1 being uniformly degradable. Furthermore, because the content is 10% by mass or less, the body 10 of the handle 1 is prevented from becoming brittle, which would excessively shorten its service life (the lifespan of the product until it becomes unusable). Additionally, the strength of the leaf spring 32 of the oscillating mechanism 3 in the body 10 of the handle 1 is maintained, making it less likely to break, thereby preventing adverse effects on the use of the razor 100. Furthermore, while suppressing increases in material costs, it is possible to suppress both a decrease in the moldability of the body 10 of the handle 1 and a decrease in the physical properties of the base resin, thereby further improving economic efficiency and more reliably achieving productivity and product performance equivalent to conventional products.

[0038] 6 is a graph conceptually showing the change in the degree of deterioration of the body 10 of the steering wheel 1 relative to the content of Degranobon as the second additive in the resin composition, based on knowledge about Degranobon. In this graph, the dashed line R1 indicates the degree of deterioration corresponding to a service life of the body 10 of the steering wheel 1 of approximately 10 years, and the dashed line R2 indicates the degree of deterioration corresponding to a service life of approximately 2 years.

[0039] The graph in Figure 6 shows that when the content of DegraNobon as the second additive is less than 1% by mass, the ratio of the additive to the base resin becomes excessively large, making it difficult for the biodegradable components contained in DegraNobon to disperse throughout the base resin, resulting in insufficient overall deterioration due to oxidative decomposition of the main body 10 of the steering wheel 1. This graph also suggests that, at first glance, increasing the content of DegraNobon as the second additive from 1% by mass causes a nearly linear increase in deterioration of the main body 10 of the steering wheel 1. However, when the content exceeds 10% by mass, which corresponds to the amount that causes deterioration equivalent to a service life of approximately two years, the effect of the second additive on the base material becomes less pronounced. Considering both cost and performance, a preferred upper limit is 10% by mass. As mentioned above, it is practically preferable to adjust the content of the second additive in the resin composition used to form the main body 10 of the steering wheel 1 within the range of 1 to 10% by mass.

[0040] (5) Furthermore, by adjusting the melt flow rate (MFR) of the resin composition used to form the main body 10 of the steering wheel 1 to 4 to 6 g / 10 min, sufficient fluidity equivalent to that achieved when the resin composition is made solely of virgin material can be achieved during molding, preventing deterioration of the molding processability of the main body 10 of the steering wheel 1. Furthermore, by adjusting the flexural modulus of the resin composition to 2000 to 2400 MPa, the leaf spring 32 of the oscillating mechanism 3 in the main body 10 of the steering wheel 1 can be given properties equivalent to those achieved when the resin composition is made solely of virgin material. As a result, it becomes possible to use existing injection molding molds for virgin materials as they are, which is extremely advantageous from the perspectives of improving economy and versatility.

[0041] (6) Furthermore, by using primarily recycled resin as the base resin, the handle 1 and razor 100 can be formed with a higher recycled material utilization rate and a lower environmental impact than when the base resin of the body 10 of the handle 1 is made solely of virgin materials. This further contributes to the 3Rs. Furthermore, by making the recycled resin content in the base resin preferably 80% by mass or more, the material cost of the base resin can be significantly reduced, making it easier to absorb the cost increase due to the use of additives, and the utilization rate of recycled materials can be sufficiently increased. As a result, economic efficiency can be improved and the environmental impact can be further reduced. Furthermore, by using recycled materials, especially pre-consumer and post-consumer materials (i.e., not including waste materials generated during the product manufacturing process), as the recycled resin, the environmental impact can be more reliably and substantially reduced.

[0042] (7) Furthermore, by using a styrene-based resin and / or a propylene-based resin as the base resin, the main body 10 of the handle 1 can be formed with excellent heat resistance, impact resistance, rigidity, moldability, dimensional stability, acid resistance, alkali resistance, etc., thereby improving product performance. Also, by making the content of the styrene-based resin and / or the propylene-based resin in the base resin preferably 60 mass% or more, there is an advantage in that it becomes easier to express the various properties of the styrene-based resin and / or the propylene-based resin.

[0043] (8) Furthermore, by setting the total content of the first and second additives in the resin composition for forming the main body 10 of the handle 1 of the razor 100 to preferably 30 mass % or less, it is possible to suppress both a decrease in the moldability of the main body 10 of the handle 1 and a decrease in the physical properties of the base resin while suppressing an increase in material costs, thereby improving economic efficiency and achieving productivity and product performance equivalent to conventional methods.

[0044] (9) Furthermore, by adjusting the content of the first additive (such as Bionobon) in the resin composition used to form the body 10 of the handle 1 to preferably 1% by mass or more, the resin composition can be sufficiently endowed with plant-derived effects. Also, by adjusting the content to 20% by mass or less, the moldability of the body 10 of the handle 1 and the physical properties of the base resin can be prevented from deteriorating to an inconvenient level, thereby improving economic efficiency and achieving productivity and product performance during use equivalent to conventional methods. [Example]

[0045] Examples 1 to 7 Resin compositions for forming the main body of a razor handle were prepared by blending a base resin (high-impact polystyrene (virgin material), product number HIPS 622P, manufactured by Shanghai Xujie New Plastic Tech Co., Ltd.) with a first additive (Bio-Nobon, manufactured by Novon Japan Co., Ltd.) and a second additive (Degra-Nobon, manufactured by Novon Japan Co., Ltd.) at various content ratios. The content ratios of each material in each of these resin compositions (all in "mass %") are shown in Table 1 below. As described below, "Example 1" is essentially a comparative example, but is referred to as such for convenience of explanation (as will be explained later).

[0046] [Table 1]

[0047] It was also confirmed that the melt flow rate of each of these resin compositions was within the range of 4 to 6 g / 10 min, and the flexural modulus was within the range of 2000 to 2400 MPa. This resin composition was injection molded using a conventional mold manufactured by the applicant under molding conditions equivalent to those of the conventional molds, to obtain a plurality (three or more) of molded products S for each of Examples 1 to 7, each having the same shape as the main body 10 of the handle 1 described in the above embodiment.

[0048] Example 8 A plurality (three or more) of molded articles S of Example 8 having the same shape as the main body 10 of the handle 1 were obtained in the same manner as Example 2, except that a mixed resin of recycled material (Kinpa Technology Japan, impact-resistant polystyrene (recycled material), product number: CK-61506 HM) and virgin material (the same as the base resin of Example 1) was used as the base resin. The content ratio (recipe) of each material in this base resin was 65% by mass of recycled material and 35% by mass of virgin material. It was also confirmed that the melt flow rate of this resin composition was in the range of 4 to 6 g / 10 min, and the flexural modulus was in the range of 2000 to 2400 MPa.

[0049] (Comparative Example 1) Multiple (three or more) molded products S of Comparative Example 1 having the same shape as the main body 10 of the handle 1 were obtained in the same manner as Example 2, except that the base resin of Example 2 was 100% by mass (i.e., the first additive and the second additive were not blended).

[0050] [Accelerated deterioration test by ultraviolet irradiation] A plurality of molded articles S of each of Examples 1 to 8 and Comparative Example 1 were placed in an accelerated weather resistance tester, a xenon weather meter WM (manufactured by Suga Test Instruments Co., Ltd., model number: S80 HBBR), as shown in the photograph in FIG. 3, and an accelerated deterioration test was carried out under the following conditions by irradiating ultraviolet rays from a xenon lamp Lm with the device closed. Xenon lamp output: 150W / m 2 Black panel temperature: 80℃ Irradiation time: 547 hours (equivalent to 10 years of sunlight at 20°C; see below for a standard guideline)

[0051] The above irradiation time was determined as the time equivalent to "10 years of irradiation with sunlight at 20°C" as follows. First, according to the Arrhenius correlation, one day of irradiation energy at 80°C is equivalent to 64 days of irradiation energy at 20°C. Therefore, first, 10 years (3650 days) of irradiation at 20°C is equivalent to 3650 / 64 ≒ 57 days of irradiation at 80°C. Also, 180W / m 2The xenon lamp output of 180 W / m² is equivalent to approximately three times the output of sunlight. Therefore, 57 days of sunlight exposure at 80°C is equivalent to 180 W / m². 2 This corresponds to 57 / 3 = 19 days (456 hours) of irradiation at 80°C using a xenon lamp. The xenon lamp output under the test conditions was 150W / m 2 Therefore, 180W / m 2 456 hours of irradiation at 80°C with a xenon lamp of 150W / m 2 This corresponds to 456 x 180 / 150 = 547 hours of irradiation with a xenon lamp at 80°C. Just to be sure, let's set an even longer time, 16 years (5,844 days) of sunlight irradiation at 20°C, and from the proportional calculation above, we get 180W / m 2 The irradiation time was set to 875 hours at 80°C using a xenon lamp.

[0052] (Deterioration progression evaluation) In the accelerated deterioration test by ultraviolet irradiation described above, the molded article S was taken out of the accelerated weathering tester xenon weather meter WM before ultraviolet irradiation and after each set period of irradiation, and was measured using a Fourier transform infrared spectrophotometer (manufactured by JASCO Corporation, model number: FT / IR-410). Graphs showing the obtained IR absorption spectra are shown in Figures 4A to 4C. In these graphs, the horizontal axis represents wave number (cm -1 ), and the vertical axis represents transmittance (the inverse of absorptance).

[0053] Figure 4A shows the results for the molded product S of Example 2, where the upper spectral curve shows the results at 0 hours of irradiation (i.e., before UV irradiation; the same applies below), and the lower spectral curve shows the results at 270 hours of irradiation (equivalent to approximately 4.9 years of sunlight irradiation at 20°C). Figure 4B shows the results for the molded product S of Example 8, where the spectral curves show the results at irradiation times of 0, 100, 200, 300, 400, 547, and 875 hours (equivalent to 0 years, approximately 1.8 years, approximately 3.7 years, approximately 5.5 years, approximately 7.3 years, and approximately 10 years of sunlight irradiation at 20°C, respectively) (approximately 16 years of irradiation has been omitted). Figure 4C shows the results for the molded product S of Comparative Example 1, where the UV irradiation times for each spectral curve are the same as those for the molded product S of Example 2 shown in Figure 4B.

[0054] In the graphs shown in these Figures 4A to 4C, the wavenumber (approximately 1700 to 1800 cm) derived from the carbonyl group generated by the radical reaction -1 The magnitude (area) of the peaks near the wavenumber region enclosed by the dashed square in each graph can be used to evaluate the yield of decomposition products in each molded product S, and thus the degree of degradation due to oxidative decomposition. As a result, the following points were discovered.

[0055] (a) Oxidative decomposition occurs in molded article S over time due to ultraviolet irradiation, regardless of the presence or absence of the first and second additives. (b) The peak value and area of ​​the part resulting from the radical reaction were larger in the molded article S (Examples 2 and 8) containing the second additive than in the molded article S (Comparative Example 1) not containing the second additive, and oxidative decomposition in the molded article S progressed more. (c) Oxidative decomposition progresses to the same extent in both molded product S (Example 2) using virgin material as the base resin and molded product S (Example 8) using recycled material.

[0056] (External observation) When the appearance of each molded product S was observed after the accelerated deterioration test using ultraviolet light irradiation was completed, discoloration was observed in all cases, but no changes were observed in the surface properties or external shape. This confirmed that the surface properties and external shape of molded product S were maintained even after the accelerated deterioration test equivalent to 10 years of exposure to sunlight at 20°C.

[0057] (destructive testing) Furthermore, for the molded articles S of Examples 1 to 7 and Comparative Example 1, each molded article S during the accelerated deterioration test was simultaneously removed at the timing of the evaluation of the deterioration progress degree (irradiation time = 0 hour, 100 hours, 200 hours, 300 hours, 400 hours, 547 hours, and 875 hours (corresponding to 0 year, about 1.8 years, about 3.7 years, about 5.5 years, about 7.3 years, about 10 years, and about 16 years of irradiation by sunlight at 20°C, respectively) and subjected to a destructive test. Here, as shown in FIG. 5A, the molded articles S were placed on a desk surface, and both ends t1 and t2 of the molded article S were supported on the desk surface, and the destructive test was performed. A load was applied in the direction indicated by the white arrow to the upper surface of the bent portion of the molded product S, approximately in the boundary region between the grip portion 11 and the head portion 12. The load was increased until the molded product S bent and the lower portion of the bent portion abutted against the table surface. Three specimens were tested for each example. If even one specimen cracked or broke, it was rated "X." If none of the three specimens cracked or broke, it was rated "O." The results are summarized in Table 2 (the molded products S of Comparative Example 1 and Example 8 showed similar results to those of Examples 1 and 2, and are therefore omitted from the table).

[0058] [Table 2]

[0059] As a result, as shown in FIG. 5B, the deteriorated molded article S developed a crack (the area within the dashed white circle in the figure) from the bottom of the bent portion and was destroyed (applied load: approximately 5 kgf). At this time, as the load was applied, whitening occurred at the bottom of the bent portion as shown, and the whitening gradually progressed inward (upward in the figure), eventually propagating to the extent shown in FIG. 5B. The other deteriorated molded articles S also followed a similar course, developing a crack from the bottom of the bent portion as shown and being destroyed (applied load: approximately 5 kgf). On the other hand, unlike the molded articles S of the other examples, the molded articles S of Example 1 and Comparative Example 1 did not develop a crack and did not experience destruction in other areas. The results of these destructive tests and the accelerated aging tests revealed that when exposed to ultraviolet light equivalent to 10 to 16 years of sunlight at 20°C, molded articles S (Examples 2 to 7) containing a predetermined amount of the second additive in the base resin were significantly more susceptible to oxidative decomposition and strength deterioration extending deep into the interior, making the internal structure brittle and more susceptible to fracture, than molded article S (Comparative Example 1) in which the second additive was not contained in the base resin or Example 1 in which a small amount was contained. As mentioned above, while "Example 1" has been referred to as an "Example" for convenience, the results in this case can also be considered substantially a "Comparative Example."

[0060] Furthermore, these results were confirmed to be in excellent agreement with the findings regarding the relationship between the content of the second additive (DegraNobon) and the deterioration of razor handles in Figure 6, which was explained above. In the previous explanation, we inferred that when the content of the second additive exceeds 10% by mass, which corresponds to the amount that causes deterioration equivalent to a useful life of approximately 2 years, product deterioration does not proceed rapidly, but rather that such a possibility is unlikely to occur due to its relationship with the amount of base resin. However, the results in Table 2 above do not necessarily indicate that the degree of deterioration progresses rapidly even when the content of the second additive exceeds 10% by mass, and rather, it can be said that there is doubt as to whether or not the degree of deterioration will saturate at around 10% by mass (however, the effect is not limited to this).

[0061] The above-described embodiments and examples have been described in detail as examples of the present disclosure. However, as mentioned above, the above description merely illustrates an example of the present disclosure in every respect, and various improvements and modifications can be made without departing from the scope of the present disclosure. Furthermore, the above-described embodiments can be configured by partially replacing, deleting, or combining parts. For example, the razor head 2 may be detachably attached to the front side of the head 12 of the main body 10 via its oscillating mechanism 3. Furthermore, a shaving aid or the like may be provided on the handle 1, and the shape of each part may be appropriately modified as long as it has the same function. Furthermore, conventional types of resin may of course be used as the base resin of the main body 10. [Explanation of symbols]

[0062] 1...handle, 2...razor head, 3...oscillating mechanism, 10...main body, 11...grip, 12...head, 20...surface member, 21...blade support portion, 22...blade body, 31...support arm, 32...leaf spring, 100...razor, Lm...xenon lamp, S...molded product, t1, t2...both ends, WM...accelerated weather resistance tester xenon weather meter.

Claims

1. A resin composition for forming a body of a handle of a razor on which a razor head is supported and which is provided with an oscillating mechanism having a leaf spring, comprising: a base resin containing a first additive containing a plant-derived component and a second additive containing a biodegradable component; The content of the second additive is 1 to 10 mass %, A melt flow rate of 4 to 6 g / 10 min. The flexural modulus is 2000 to 2400 MPa. Resin composition.

2. The base resin mainly contains recycled resin, The content of the recycled resin in the base resin is 90% by mass or more. The resin composition according to claim 1.

3. the base resin mainly contains a styrene-based resin and / or a propylene-based resin, The content of the styrene-based resin and / or the propylene-based resin in the base resin is 60% by mass or more. The resin composition according to claim 1 or 2.

4. The total content of the first and second additives is 30% by mass or less. The resin composition according to any one of claims 1 to 3.

5. The content of the first additive is 1 to 20 mass%. The resin composition according to any one of claims 1 to 4.

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