Resin molding and method for manufacturing the same

Abstract

To provide a resin molding which can supply a contained active ingredient to outside for a long period, and a method for manufacturing the same.SOLUTION: A resin molding is composed of a resin component and an oil component, wherein the content ratio of the resin component and the oil content is 1:9 to 9:1 in a weigh ratio, a molecular weight of a resin contained in the resin component is 7×104 to 700×104, the resin molding includes a shell part constituting an outer shell and a core part included in the shell part, the shell part is formed by fusing a part of a surface layer of the resin particles composed of the resin component each other, and connecting it with a gap serving as a flow channel of the oil component, the core part contains a resin component and an oil component, and the oil component contained in the core part passes through the gap provided on the shell part and is oozed out to the surface for a long period.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present application relates to a resin molded product and a method for manufacturing the same. [Background technology]

[0002] In recent years, automation and labor-saving technologies for industrial machinery and machine tools have been developing significantly as an urgent issue due to the decline in the labor force. One of the technologies supporting this development is maintenance-free technology. A representative example of maintenance-free technology is the automation of lubricating oil supply (automatic lubricating oil supply). Generally, automatic lubricating devices are used to automate the lubricating oil supply.

[0003] Meanwhile, it has also been proposed that lubricating oil be automatically supplied by the parts themselves that are incorporated into the machine. Patent Document 1 discloses "a sliding member including a molded body of a composition for a sliding member, which includes a base material containing a resin component, a first lubricant configured to act at the initial stage of sliding, and a second lubricant configured to act after the initial stage of sliding and having a higher viscosity than the first lubricant."

[0004] Patent Document 2 discloses a sliding member made of a resin composition for sliding members which contains, in addition to a synthetic resin as a main component, 1 to 30 mass % of a lubricating oil, 0.25 to 32 mass % of a wood-based filler, 0.65 to 36 mass % of a polyolefin resin, and 0.005 to 6.8 mass % of a compatibilizer as additives.

[0005] In addition to these technologies related to the automation of lubricating oil supply and delivery, there are also known technologies for preventing pests such as mosquitoes and ants from invading indoors and protecting crops from insect damage by slowly releasing and dispersing medicinal ingredients such as certain fragrances, insect repellents, and hormone-like substances into the required atmosphere. These technologies are utilized and commercialized in the form of resin molded products in which medicinal ingredients are kneaded into the resin base material. Among these, simple products include insect repellent rings that can be worn on the wrist or ankle to protect the human body from pests such as mosquitoes and mites for long periods of time.

[0006] Patent Document 3 discloses "a pest repellent leg band in which a natural insect repellent ingredient made from a plant essential oil such as peppermint oil is contained in a constituent material of the leg band made from resin." Here, the method of incorporating the plant essential oil into the resin material in Patent Document 3 is by kneading (mixing) or coating (applying). These techniques have in common that active ingredients such as lubricating oil or insect repellent ingredients contained in the resin molded product are supplied to the outside of the resin molded product, whereby the active ingredients function and produce their effects. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-14891 [Patent Document 2] Japanese Patent Publication No. 2020-26485 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-51564

[0008] However, obtaining the sliding member of Patent Document 1 requires preliminary steps such as supporting the first lubricant, which acts at the initial stage of sliding, on porous particles such as graphite or microencapsulating it in a resin film, resulting in labor-intensive manufacturing. Furthermore, obtaining the sliding member of Patent Document 2 requires three raw materials: a wood-based filler, a polyolefin resin, and a compatibilizer, in addition to a synthetic resin and a lubricating oil, resulting in a problem of relatively high manufacturing costs. Furthermore, the total content of the first lubricant and the second lubricant in the sliding member composition constituting the sliding member of Patent Document 1 is approximately 3.8% by mass to 33% by mass, while the content of the lubricating oil in the sliding member composition constituting the sliding member of Patent Document 2 is 1% by mass to 30% by mass, leaving room for improvement.

[0009] Furthermore, the insect repellent leg band of Patent Document 3 has a relatively short duration of insect repellent effect of about 7 hours (commercially available insect repellent rings have a duration of about 12 hours). Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention aims to provide a resin molded product and a method for manufacturing the same that can supply a contained active ingredient to the outside over a long period of time. More specifically, when the contained active ingredient is a lubricating oil, the object is to provide a resin molded product and a method for manufacturing the same that allows the parts incorporated into the machine to have self-lubricating properties and automatically supply lubricating oil to the machine over a long period of time with a relatively simple configuration. Furthermore, when the contained active ingredient is a fragrance or insect repellent, the object is to provide a resin molded product and a method for manufacturing the same that allows the effects of the active ingredient, such as emitting a fragrance to the surrounding area and protecting the human body and clothing from pests, to be obtained over a longer period of time than in the prior art. [Means for solving the problem]

[0011] A.Resin molded products The resin molded article according to the present application is composed of a resin component and an oil component, and the weight ratio of the resin component to the oil component is 1:9 to 9:1, and the molecular weight of the resin contained in the resin component is 7×10 4 ~700×10 4 The composition is characterized in that it comprises a shell portion constituting an outer shell and a core portion enclosed by the shell portion, and the shell portion is formed by connecting portions of the surface layers of resin particles made of a resin component by fusing together to form voids that serve as flow paths for the oil component, and the core portion contains a resin component and an oil component, and the oil component contained in the core portion seeps out to the surface over a long period of time through the voids provided in the shell portion.

[0012] The specific heat at the melting temperature of the resin particles in the resin molded article according to the present application is preferably 5 J / g·K to 30 J / g·K.

[0013] The average particle size of the resin particles in the resin molded article according to the present application is preferably 1 μm to 200 μm.

[0014] The thickness of the shell of the resin molded product according to the present application is 50 μm to 10 × 10 3 It is preferable that the thickness is μm.

[0015] The resin contained in the resin component of the resin molded article according to the present application is preferably one or more resins selected from the group consisting of polyethylene, polyacetal, polyethylene glycol, and ABS.

[0016] The oil component of the resin molded article according to the present application preferably contains one or more oils selected from the group consisting of paraffin oil, naphthene oil, silicone oil, α-olefin oil, jojoba oil, and olive oil.

[0017] The kinematic viscosity of the oil component constituting the resin molded product according to the present application at 37.8°C to 40°C is 5mm 2 / s~750mm 2 / s is preferred.

[0018] The resin component of the resin molded article according to the present application preferably contains a colorant or pigment.

[0019] The oil component of the resin molded article according to the present application preferably contains one or more selected from the group consisting of antioxidants, corrosion inhibitors, extreme pressure agents, thickeners, fragrances, and insect repellent components.

[0020] B. Manufacturing methods for resin molded products The method for producing a resin molded article according to the present application is a method for producing the above-mentioned resin molded article according to the present application, and is characterized by comprising the following steps 1 to 3. Step 1: Molecular weight 7×10 4 ~700×10 4 Resin particles made of a resin component containing the resin and an oil component are mixed in a weight ratio of 1:9 to 9:1, and the mixture is poured into a mold. Step 2: The molding die containing the resin particles and oil components is heated to 140°C to 360°C and left to stand for 10 seconds to 50 minutes. Step 3: After being left standing, the molding mold is allowed to cool, and the contents are removed from the molding mold to obtain a resin molded product.

[0021] The specific heat at the melting temperature of the resin particles used in the method for producing a resin molded article according to the present application is preferably 5 J / g·K to 30 J / g·K.

[0022] The resin particles used in the method for producing a resin molded article according to the present application preferably have an average particle size of 1 μm to 200 μm.

[0023] The kinematic viscosity of the oil component used in the manufacturing method of the resin molded product according to the present application at 37.8°C to 40°C is 5mm 2 / s~750mm 2 / s is preferred. [Effects of the Invention]

[0024] The present invention provides a resin molded article and a method for manufacturing the same that can supply the active ingredient contained therein to the outside for a long period of time, such as several years. More specifically, when the active ingredient contained therein is a lubricating oil, a self-lubricating resin molded article and a method for manufacturing the same can be provided that can automatically supply lubricating oil to devices such as industrial machinery, machine tools, and power tools for a long period of time, such as one to five years, with a relatively simple configuration. Furthermore, when the active ingredient contained therein is a fragrance or insect repellent, a resin molded article and a method for manufacturing the same can be provided that can provide the effects of the active ingredient, such as emitting a fragrance to the surrounding area and protecting the human body and clothing from pests, for a longer period of time, such as one to three years, compared to conventional techniques. [Brief explanation of the drawings]

[0025] [Figure 1] Graphs (A) and (B) show the specific heat of the resin particles used in the examples near their melting temperatures. [Figure 2] 1 is a graph showing the results of thermal analysis of resin particles used in Examples, performed with a differential scanning calorimeter. [Figure 3] (A) and (B) are optical microscope images of the test piece in the example, (C) and (D) are optical microscope images of the test piece in the example after staining. [Figure 4] (A) and (B) are images of the test piece in the example after staining, observed by an X-ray μCT device. (C) and (D) are images of the shell portion of the test piece in the example after staining, observed by an X-ray μCT device. [Figure 5] FIG. 1 is a pore size distribution diagram of a test piece in an example, measured using an X-ray μCT device. [Figure 6] 1 is a graph showing the pore size distribution of a test piece in an example, measured with an X-ray μCT device. [Figure 7] 1 is a graph showing the results of a tensile strength test of test pieces in Examples. [Figure 8] 1A and 1B are electron microscope images of the shell portion of a test piece in an example in which the oil component was replaced with ethanol. [Figure 9] 1A to 1F are optical microscope images of test pieces in the examples. [Figure 10] Graphs (A) and (B) show the specific heat of the resin particles used in the examples near their melting temperatures. [Figure 11] 1 is a graph showing the results of thermal analysis of resin particles used in Examples, performed with a differential scanning calorimeter. [Figure 12] 1 is a graph showing the specific heat of resin particles used in a comparative example near the melting temperature. [Figure 13] 1 is a graph showing the results of thermal analysis of resin particles used in Comparative Examples, performed with a differential scanning calorimeter. DETAILED DESCRIPTION OF THE INVENTION

[0026] A.Resin molded products The resin molded article according to the present application is composed of a resin component and an oil component, and the weight ratio of the resin component to the oil component is 1:9 to 9:1. The molecular weight of the resin contained in the resin component is 7×104 ~700×10 4 The resin molded article according to the present application comprises a shell portion constituting an outer shell and a core portion enclosed within the shell portion, and the shell portion is formed by connecting resin particles made of a resin component in a state in which the surface layers of the resin particles are partially fused together to form voids that serve as flow paths for the oil component. The core portion contains a resin component and an oil component, and the oil component contained in the core portion seeps out to the surface over a long period of time through the voids in the shell portion.

[0027] (Overall structure) As described above, the resin molded article according to the present application is composed of a resin component and an oil component. Here, the resin component contains a resin with a relatively high molecular weight as a primary component. After extensive research, the present inventors discovered that resin particles composed of such a resin component have a high specific heat capacity near their melting temperature. A mixture of the resin particles and an oil component primarily composed of a base oil (also referred to as a base oil or carrier oil) was placed in a molding mold and heated, resulting in a resin molded article with a core-shell structure (double structure). Further, upon closer observation of the resin molded article, it was found that the shell portion constituting the outer shell was formed by only portions of the surface layer of the resin particles fusing with adjacent resin particles, resulting in three-dimensional connections with voids remaining between the resin particles. Furthermore, a core portion containing the resin component and the oil component was formed inside the shell portion. Various tests using the resin molded article revealed that the resin molded article had excellent self-lubricating properties. Furthermore, oil components containing fragrances or insect repellent ingredients as secondary ingredients have the ability to diffuse the fragrances or insect repellent ingredients to the outside of the resin molded product. Therefore, it can be concluded that the voids between the resin particles in the shell serve as flow paths for the oil component contained in the core, and that the oil component contained in the core encapsulated by the shell oozes (bleeds) through the voids onto the surface of the resin molded product in very small amounts.

[0028] (Ingredients included) The resin component contains a resin with a relatively large molecular weight as a main component. There are no particular limitations on the type of resin contained in the resin component, and examples of usable resins include thermoplastic resins such as polyethylene (PE), polyacetal (POM), polyethylene glycol (PEG), and ABS (a resin made of acrylonitrile, butadiene, and styrene). Resins made of straight-chain hydrocarbons with a molding shrinkage rate of approximately 2% to 6% can also be suitably used. These resins are preferred because they are relatively easy to obtain and inexpensive. It is also preferred that the resin component contain additives such as dyes and pigments as secondary components.

[0029] The oil component primarily contains a base oil such as mineral oil (also called mineral oil), synthetic oil (also called chemically synthesized oil), or vegetable oil. The type of base oil is not particularly limited, and examples of base oils that can be used include paraffin oil (also called liquid paraffin), naphthenic oil, silicone oil, α-olefin oil, jojoba oil, and olive oil. These base oils are preferred because they are relatively easy to obtain and inexpensive. It is also preferable for the oil component to contain additives such as antioxidants, corrosion inhibitors, extreme pressure agents, and thickeners as secondary ingredients. When the base oil contained in the oil component is used primarily as a carrier for transporting active ingredients to the outside of a resin molded article, adding active ingredients such as fragrances and insect repellents as secondary ingredients to the oil component can enhance the effects of the active ingredients when the resin molded article is used. Oil components containing these ingredients function as lubricants or perfume oils.

[0030] When the oil component contains minor components such as antioxidants, corrosion inhibitors, extreme pressure agents, thickeners, fragrances, and insect repellents, the preferred total content of the minor components in the oil component is 0.5 wt% to 8 wt%. A total content of the minor components in the oil component of less than 0.5 wt% is undesirable because the antioxidant and corrosion inhibitor effects of the minor components tend to be insufficient. On the other hand, a total content of the minor components in the oil component of more than 8 wt% results in a relative decrease in the base oil content in the oil component. Therefore, when the resin molded article is used as a part such as a gear or washer incorporated into equipment such as industrial machinery, machine tools, or tools, the oil component does not function well as a lubricant, and the ability to supply lubricant to the equipment tends to decrease, which is undesirable. Furthermore, the base oil in the oil component tends to decrease the ability to transport active ingredients such as fragrances and insect repellents to the outside of the resin molded article, which is undesirable. If the total content of the auxiliary ingredients in the oil component exceeds 8 wt %, and the auxiliary ingredients are fragrances and / or insect repellent ingredients, this is undesirable as it may have unexpected adverse effects on the human body.

[0031] Furthermore, the kinematic viscosity of the oil component at 37.8℃ to 40℃ is 5mm 2 / s~750mm 2 The kinematic viscosity of the oil component at 37.8°C to 40°C is preferably 5mm / s. 2 Even if the kinematic viscosity is less than 750mm / s, the performance of lubricating equipment such as industrial machines, machine tools, and tools, or the performance of transporting active ingredients such as fragrances and insect repellents to the outside of resin molded articles will not be significantly improved, and it tends to be difficult to reproducibly manufacture core-shell structured resin molded articles by molding methods, which is not preferable. 2If the viscosity exceeds 1 / s, the fluidity of the oil component will decrease, which is undesirable because when the resin molded article is used as a part such as a gear or washer incorporated into equipment such as industrial machinery, machine tools, or tools, the ability to supply lubricating oil to the equipment will tend to decrease.Furthermore, the ability of the base oil in the oil component to transport active ingredients such as fragrances and insect repellents to the outside of the resin molded article will tend to decrease, which is undesirable.

[0032] The preferred ratio of the resin component to the oil component in the resin molded product according to the present application is 1:9 to 9:1 by weight. Here, if the ratio of the resin component to the oil component is less than 1 by weight, the thickness of the shell portion constituting the outer shell of the resin molded product becomes too small, reducing the strength and durability of the resin molded product. This tends to make it difficult to use the resin molded product as parts such as gears and washers to be incorporated into equipment such as industrial machinery, machine tools, and tools, or as products such as insect repellent rings containing fragrances and / or insect repellent ingredients, which is undesirable. On the other hand, if the ratio of the resin component to the oil component exceeds 9 by weight, the ratio of the oil component to the resin component becomes relatively less than 1 by weight. Therefore, when the resin molded product is used as parts such as gears and washers to be incorporated into equipment such as industrial machinery, machine tools, and tools, the effect of supplying lubricating oil to the equipment tends to disappear in a relatively short period of time, which is undesirable. Furthermore, if the weight ratio of the resin component to the oil component exceeds 9, the weight ratio of the oil component to the resin component will be relatively less than 1, and if the oil component contains an active ingredient such as a fragrance or an insect repellent as a secondary ingredient, the content of the active ingredient in the oil component will be very small. As a result, the effects of the active ingredient, such as emitting a fragrance to the surrounding area or protecting the human body and clothing from pests, tend to disappear in a relatively short period of time, which is undesirable.

[0033] As described above, the resin component constituting the resin molded article according to the present application contains a resin having a relatively large molecular weight as a main component. The preferred molecular weight of the resin is 7×10 4 ~700×10 4 Here, the molecular weight of the resin is 7 × 10 4If the temperature is less than this, the specific heat capacity of the resin particles composed of the resin component near the melting temperature becomes small. Therefore, when various parts are produced by molding using the resin particles and an oil component mainly composed of a base oil, the entire resin particle melts, and voids that serve as flow paths for the oil component tend to be less likely to form in the shell portion that constitutes the outer shell of the resin molded product. As a result, the oil component contained in the core portion does not ooze out to the surface of the resin molded product, and when the resin molded product is used as a part such as a gear or washer incorporated into equipment such as industrial machinery, machine tools, or tools, the effect of supplying lubricating oil to the equipment tends to be insufficient, which is undesirable. Furthermore, when the oil component contains active ingredients such as fragrances or insect repellents as secondary ingredients, the effects of the active ingredients, such as emitting a fragrance to the surrounding area or protecting the human body and clothing from pests, tend to be significantly ineffective, which is undesirable.

[0034] On the other hand, the molecular weight of the resin is 700 × 10 4 Even if the molecular weight of the resin exceeds 7 × 10, when the resin molded product is used as a part such as a gear or washer to be incorporated into equipment such as industrial machinery, machine tools, or tools, the performance of supplying lubricating oil to the equipment, and when the oil contains active ingredients such as fragrances or insect repellents as secondary ingredients, the performance of the active ingredients such as emitting a fragrance to the surrounding area or protecting the human body and clothing from pests, will not be improved, and problems such as limitations on the types of resin that can be used tend to occur, making it undesirable. 4 ~300×10 4 This is more preferable because the resin material is relatively easy to obtain and inexpensive.

[0035] Furthermore, the specific heat capacity of the resin particles in the resin molded product according to the present application at their melting temperatures is preferably 5 J / g·K to 30 J / g·K. Here, if the specific heat capacity of the resin particles at their melting temperatures is less than 5 J / g·K, the resin particles melt relatively easily when heated. Therefore, when various parts are manufactured by molding using the resin particles and an oil component primarily composed of a base oil, voids that serve as a flow path for the oil component tend to be less likely to form in the shell that constitutes the outer shell of the resin molded product. As a result, the oil component contained in the core does not seep onto the surface of the resin molded product. Therefore, when the resin molded product is used as a part such as a gear or washer incorporated into equipment such as industrial machinery, machine tools, or tools, the effect of supplying lubricating oil to the equipment tends to be insufficient, which is undesirable. Furthermore, when the oil component contains active ingredients such as fragrances or insect repellents as secondary ingredients, the effects of the active ingredients, such as emitting a fragrance or protecting the human body or clothing from pests, tend to be significantly less pronounced, which is undesirable. On the other hand, even if the specific heat at the melting temperature of the resin particles exceeds 30 J / g K, when the resin molded article is used as a part such as a gear or washer to be incorporated into equipment such as industrial machinery, machine tools, or power tools, the performance of supplying lubricating oil to the equipment, or the performance of the active ingredient such as a fragrance or insect repellent contained in the oil component as a secondary ingredient, such as emitting a fragrance to the surrounding area or protecting the human body and clothing from pests, is not improved, and such a condition is not preferable because it tends to cause problems such as limiting the types of resins that can be used.

[0036] The average particle size of the resin particles is preferably 1 μm to 200 μm. If the average particle size of the resin particles is less than 1 μm, the size of the voids formed between adjacent resin particles becomes too small. Therefore, when the resin molded article is used as a part such as a gear or washer incorporated into equipment such as industrial machinery, machine tools, or tools, it tends to be difficult to stably supply lubricating oil to the equipment, which is undesirable. Furthermore, when the oil component contains an active ingredient such as a fragrance or an insect repellent as a secondary ingredient, the base oil in the oil component tends to be difficult to stably transport the active ingredient such as a fragrance or an insect repellent to the outside of the resin molded article, which is undesirable. On the other hand, if the average particle size of the resin particles exceeds 200 μm, the size of the voids formed between adjacent resin particles becomes too large, which reduces the strength and durability of the resin molded article, which tends to be difficult to use as a part such as a gear or washer incorporated into equipment such as industrial machinery, machine tools, or tools, or as a product such as an insect repellent ring containing a fragrance and / or an insect repellent. Furthermore, it is more preferable for the resin particles to have an average particle size of 5 μm to 75 μm, since the size of the voids generated between adjacent resin particles becomes more suitable and the exudation rate of the oil component tends to be easier to control.

[0037] (shell part) The average size of the voids between the resin particles in the shell, which serve as flow paths for the oil component (also referred to as the average void diameter), corresponds to the average particle size of the resin particles. While this average void diameter varies depending on the average particle size of the resin particles, it is preferably 0.3 μm to 60 μm. An average void diameter of less than 0.3 μm is undesirable because it tends to make it difficult to stably supply lubricating oil to the equipment when the resin molded article is used as a part such as a gear or washer incorporated into equipment such as industrial machinery, machine tools, or tools. Furthermore, when the oil component contains active ingredients such as fragrances or insect repellents as secondary ingredients, it tends to make it difficult for the base oil in the oil component to stably transport the active ingredients such as fragrances or insect repellents to the outside of the resin molded article. On the other hand, an average void diameter exceeding 60 μm is undesirable because it reduces the strength and durability of the resin molded article, making it difficult to use the resin molded article as parts such as gears and washers incorporated into industrial machinery, machine tools, and tools, or as products such as insect rings containing fragrances and / or insect repellents. Furthermore, an average void diameter exceeding 60 μm is undesirable because excessive oil components seep onto the surface of the resin molded article, which tends to reduce the lubrication effect of the resin molded article when used as parts such as gears and washers incorporated into industrial machinery, machine tools, and tools, and the effects of the active ingredients, such as providing lubricating oil to the equipment and, when the oil ingredients contain active ingredients such as fragrances or insect repellents as secondary ingredients, emitting a fragrance to the surrounding area and protecting the human body and clothing from pests, within a relatively short period of time. Furthermore, an average void diameter of 0.3 μm to 15 μm is more preferable because it tends to make it easier to control the exudation rate of the oil ingredients.

[0038] The voids in the shell communicate with the outermost layer of the shell to the core contained within the shell, and the oil component contained in the core seeps through the voids in the shell to the surface of the resin molded product over a long period of time. Furthermore, although the shape of the voids in the shell is irregular, the average void diameter is roughly determined according to the average particle size of the resin particles made of the resin component, as described above.

[0039] The thickness of the shell portion of the resin molded product according to the present application is 50 μm to 10 × 10 3 It is preferable that the thickness of the shell portion is less than 50 μm. If the thickness of the shell portion is less than 50 μm, the strength and durability of the resin molded product will decrease, and it will tend to be difficult to use the resin molded product as parts such as gears and washers to be incorporated into equipment such as industrial machines, machine tools, and tools, or as products such as insect repellent rings containing fragrances and / or insect repellent ingredients, which is not preferable. On the other hand, if the thickness of the shell portion is less than 10×10 3 Even if the particle size exceeds 1 μm (1 cm), when the resin molded article is used as a part such as a gear or washer to be incorporated into equipment such as industrial machinery, machine tools, or tools, the performance of stably supplying lubricating oil to the equipment, and when the oil component contains an active ingredient such as a fragrance or an insect repellent as a secondary ingredient, the performance of the active ingredient such as emitting a fragrance to the surroundings or protecting the human body and clothing from pests, tend to be reduced, which is undesirable.

[0040] (Core part) The core portion of the resin molded article according to the present application contains an oil component as a main component and a resin component. The resin component is present within the core portion in the form of particles, fibers, strings, spider webs, or the like. The core portion has a structure in which the resin component within the core portion is bonded to an extent that the resin particles forming the shell portion do not separate and the resin molded article can maintain its shape without deformation, while retaining the fluid oil component. From the viewpoint of improving the strength and durability of the resin molded article, it is preferable that a portion of the resin component be fused to the resin particles of the shell portion or extend from the surface of the resin particles of the shell portion.

[0041] B. Manufacturing methods for resin molded products The method for producing a resin molded article according to the present application is a method for producing the above-mentioned resin molded article according to the present application, and is characterized by comprising the following steps 1 to 3.

[0042] Step 1: Molecular weight 7×10 4 ~700×10 4Resin particles made of a resin component containing the resin and an oil component are mixed in a weight ratio of 1:9 to 9:1, and the mixture is poured into a mold.

[0043] In this step 1, first, resin particles made of a resin component whose main component is a resin having a predetermined molecular weight and an oil component are prepared. These are mixed at a predetermined content ratio and poured into a molding mold. There are no particular restrictions on the type of resin contained in the resin component, and examples of resins that can be used include thermoplastic resins such as polyethylene (PE), polyacetal (POM), polyethylene glycol (PEG), and ABS (a resin made of acrylonitrile, butadiene, and styrene). Resins made of straight-chain hydrocarbons with a molding shrinkage rate of around 2% to 6% can also be used suitably. Furthermore, the resin component can also contain dyes or pigments as secondary components.

[0044] The oil component primarily contains a base oil (also referred to as a carrier oil) such as mineral oil, synthetic oil, or vegetable oil. The type of base oil is not particularly limited, and examples of base oils that can be used include paraffin oil (also referred to as liquid paraffin), naphthenic oil, silicone oil, α-olefin oil, jojoba oil, and olive oil. The oil component may also contain additives such as antioxidants, corrosion inhibitors, extreme pressure agents, and thickeners as secondary components. When the base oil contained in the oil component is primarily used as a carrier to transport active ingredients to the outside of a resin molded article, the oil component can contain active ingredients such as fragrances or insect repellents, thereby enabling the active ingredients to exert their effects when the resin molded article is used. Oil components containing these ingredients function as lubricants or perfume oils.

[0045] When the oil component contains minor components such as antioxidants, corrosion inhibitors, extreme pressure agents, thickeners, fragrances, and insect repellents, the preferred total content of the minor components in the oil component is 0.5 wt% to 8 wt%. A total content of the minor components in the oil component of less than 0.5 wt% is undesirable because the antioxidant and corrosion inhibitor effects of the minor components tend to be insufficient. On the other hand, a total content of the minor components in the oil component of more than 8 wt% results in a relative decrease in the base oil content in the oil component. Therefore, when the resin molded article is used as a part such as a gear or washer incorporated into equipment such as industrial machinery, machine tools, or tools, the oil component does not function well as a lubricant, and the ability to supply lubricant to the equipment tends to decrease, which is undesirable. Furthermore, the base oil in the oil component tends to decrease the ability to transport active ingredients such as fragrances and insect repellents to the outside of the resin molded article, which is undesirable. If the total content of the auxiliary ingredients in the oil component exceeds 8 wt %, and the auxiliary ingredients are fragrances and / or insect repellent ingredients, this is undesirable as it may have unexpected adverse effects on the human body.

[0046] Furthermore, the specific heat at the melting temperature of the resin particles used in the method for producing a resin molded article according to the present application is preferably 5 J / g·K to 30 J / g·K. If the specific heat at the melting temperature of the resin particles is less than 5 J / g·K, the resin particles will easily melt when the mold containing the resin particles and oil component is heated in the subsequent process. Therefore, when various parts or products are produced by molding using the resin particles and an oil component primarily composed of a base oil, voids that serve as a flow path for the oil component tend to be less likely to form in the shell that forms the outer shell of the resin molded article. As a result, the oil component contained in the core does not seep out onto the surface of the resin molded article. Therefore, when the resin molded article is used as a part such as a gear or washer incorporated into equipment such as industrial machinery, machine tools, or tools, the effect of supplying lubricating oil to the equipment tends to be less likely to be obtained, which is undesirable. Furthermore, when the oil component contains active ingredients such as fragrances or insect repellents as secondary ingredients, the effects of the active ingredients, such as emitting a fragrant aroma or protecting the human body or clothing from pests, tend not to be significantly achieved, which is undesirable.On the other hand, even if the specific heat at the melting temperature of the resin particles exceeds 30 J / g·K, when the resin molded product is used as a part such as a gear or washer incorporated into industrial machinery, machine tools, or other equipment, the performance of supplying lubricating oil to the equipment is not improved, and when the oil component contains active ingredients such as fragrances or insect repellents as secondary ingredients, the effects of the active ingredients, such as emitting a fragrant aroma or protecting the human body or clothing from pests, tend not to be improved, and problems such as limitations on the types of resins that can be used tend to occur.

[0047] The average particle size of the resin particles used in step 1 is preferably 1 μm to 200 μm. When the molecular weight of the resin, which is the main component of the resin component constituting the resin particles, is within a predetermined range, when a mixture of the resin particles and an oil component mainly composed of a base oil is placed in a molding mold and heated, only the surface layer of the resin particles melts. A portion of the resin particles then fuses with adjacent resin particles, forming a three-dimensional connection while leaving voids between the resin particles, forming the shell portion that constitutes the outer shell of the resin molded product. Therefore, the average particle size of the resin particles constituting the shell portion is close to the average particle size of the resin particles used as the raw material. Therefore, if the average particle size of the resin particles used as the raw material in step 1 is less than 1 μm, the average particle size of the resin particles constituting the shell portion of the resin molded product will also be less than 1 μm, and the size of the voids between adjacent resin particles in the shell portion will be too small. As a result, when the resin molded product is used as a part such as a gear or washer incorporated into equipment such as industrial machinery, machine tools, or tools, it tends to be difficult to stably supply lubricating oil to the equipment, which is undesirable. Furthermore, when the oil component contains an active ingredient such as a fragrance or an insect repellent as a secondary ingredient, the base oil in the oil component tends to make it difficult to stably transport the active ingredient such as the fragrance or the insect repellent to the outside of the resin molded product, which is not preferable.

[0048] On the other hand, if the average particle size of the resin particles used as the raw material in Step 1 exceeds 200 μm, the average particle size of the resin particles constituting the shell portion of the resin molded article will also increase accordingly, resulting in excessively large voids between adjacent resin particles in the shell portion. As a result, the strength and durability of the resin molded article will decrease, making it difficult to use the resin molded article as parts such as gears and washers incorporated into industrial machinery, machine tools, and other equipment, or as products such as insect repellent rings containing fragrances and / or insect repellent ingredients, which is undesirable. Furthermore, if the average particle size of the resin particles used in Step 1 is 5 μm to 75 μm, the size of the voids between adjacent resin particles in the shell portion will be more suitable, making it easier to control the exudation rate of the oil component, which is more preferable. Furthermore, if the molecular weight of the resin used in Step 1 is less than 7×104 ~300×10 4 This is more preferable because the resin as a raw material can be obtained relatively easily and inexpensively.

[0049] The kinematic viscosity of the oil component used in the manufacturing method of the resin molded product according to the present application at 37.8°C to 40°C is 5mm 2 / s~750mm 2 / s. Here, it is preferable that the kinematic viscosity of the oil component at 37.8°C to 40°C is 5mm 2 If the kinematic viscosity is less than 750 mm / s, it becomes difficult to mix the resin particles and the oil component evenly, and a homogeneous resin molded product tends not to be obtained, which is undesirable. 2 Even if the viscosity exceeds 1 / s, the fluidity of the oil component decreases, which is undesirable because when the resin molded article is used as a part such as a gear or washer incorporated into equipment such as industrial machinery, machine tools, or tools, the ability to supply lubricating oil to the equipment tends to decrease.Furthermore, it is undesirable because the ability of the base oil in the oil component to transport active ingredients such as fragrances and insect repellents to the outside of the resin molded article tends to decrease.

[0050] There are no particular limitations on the method for mixing the resin particles and the oil component and the method for injecting the mixture into the molding die in step 1, and any conventionally known method may be used. For example, the resin particles and the oil component, weighed to a predetermined content ratio, may be introduced into a material inlet of a molding machine, mixed by rotation, stirring, or the like in a material mixing section of the molding machine, and then injected into the recess of the molding die from a material inlet provided in the molding die, such as a metal die having good thermal conductivity such as aluminum alloy or stainless steel.

[0051] Here, when the oil component contains secondary components such as antioxidants, corrosion inhibitors, extreme pressure agents, thickeners, fragrances, and insect repellents, it is preferable to premix the primary base oil and the secondary components. Specifically, for example, the primary and secondary components of the oil component, which are raw materials for the method of manufacturing a resin molded product according to the present application, may be introduced into a material inlet of a molding machine and mixed by rotation, stirring, or other methods in a material mixing section of the molding machine. The resin component may then be introduced into the material inlet and mixed again by rotation, stirring, or other methods in the material mixing section. Using such a method, an oil component in which the secondary components are more uniformly mixed with the primary component can be obtained, and the secondary components can be transported to the exterior of the resin molded product by the primary component, thereby stably performing their functions. Furthermore, if the secondary component is highly volatile, premixing it with the primary component can suppress volatilization of the secondary components from the oil component when a mold containing resin particles and the oil component is heated in the subsequent process. In step 1, it is also preferable to apply a mold release agent to the inner surface of the molding die before injecting the resin particles and oil component into the molding die.

[0052] Step 2: The molding die containing the resin particles and oil components is heated to 140°C to 360°C and left to stand for 10 seconds to 50 minutes.

[0053] In step 2, the molding mold containing the resin particles and oil component injected in step 1 is heated to a predetermined temperature and allowed to stand at that temperature for a predetermined time. The surface layers of the resin particles, whose main component is a resin having the molecular weight specified in step 1, are melted by the heat treatment in step 2, leaving voids between the resin particles, and some of the resin particles are three-dimensionally fused and connected to adjacent resin particles to form a shell portion that constitutes the outer shell of the resin molded product. If the content ratio of the resin particles to the oil component is within the range specified in step 1, the thickness of the shell portion will be suitable from the standpoints of the strength required for using the resin molded product as a mechanical part such as a gear or washer, and the ability to supply lubricating oil to industrial machinery, machine tools, tools, and other equipment. Furthermore, when the oil component contains an active ingredient such as a fragrance or an insect repellent ingredient as a secondary ingredient, the resin molded article is suitable from the viewpoints of the strength required for use as a product such as an insect repellent ring containing the fragrance and / or insect repellent ingredient, and the ability of the base oil in the oil component to stably transport the active ingredient such as the fragrance or insect repellent ingredient to the outside of the resin molded article.

[0054] Here, if the heating temperature of the molding mold into which the resin particles and oil component are injected in step 1 is less than 140°C, the resin particle surfaces will not melt, and molded resin products will tend to be difficult to reproducibly obtain, which is undesirable. On the other hand, if the heating temperature exceeds 360°C, the performance of the resulting molded resin product will not be significantly improved, the production costs will increase, and molded resin products with good appearance will tend to be difficult to obtain, which is undesirable. Furthermore, if the oil component contains a highly volatile minor component, even if the oil component is prepared by pre-mixing the main base oil with the minor component, when the mold containing the resin particles and oil component is heated in step 2, the minor component in the oil component will volatilize, which is undesirable, and the effects of the active ingredient, such as emitting a fragrance to the surrounding area and protecting the human body and clothing from pests, will tend to be reduced, which is undesirable.

[0055] Furthermore, if the molding mold into which the resin particles and oil component have been injected in step 1 is allowed to stand at the predetermined heating temperature for less than 10 seconds, it tends to be difficult to reproducibly produce a homogeneous molded resin product, which is undesirable. On the other hand, if the molding mold into which the resin particles and oil component have been injected in step 1 is allowed to stand at the predetermined heating temperature for more than 50 minutes, the performance of the resulting molded resin product is not significantly improved, and the production process tends to take longer and the production costs tend to increase, which is undesirable. Furthermore, if the molding mold into which the resin particles and oil component have been injected in step 1 is allowed to stand at the predetermined heating temperature for more than 50 minutes, when a highly volatile minor component is contained in the oil component, even if the oil component is prepared by pre-mixing the main base oil with the minor component, the minor component in the oil component will volatilize when the mold containing the resin particles and oil component is heated in step 2, which tends to reduce the effects of the minor component, such as emitting a fragrance to the surrounding area and protecting the human body and clothing from pests, which is undesirable.

[0056] However, even if the heat treatment time in Step 2 is extended to 50 minutes or longer, there is no risk of the voids in the shell of the resin molded product obtained by the manufacturing method of the present application disappearing, as long as the molecular weight of the resin in the resin component constituting the resin particles used as the raw material and / or the corresponding specific heat around the melting temperature of the resin particles are within a predetermined range. If the resin particles used as the raw material have such characteristics, the resin particles will not melt all the way to their centers at the heat treatment temperature specified in Step 2, but only the surface layer. Then, when the resin particles with only the surface layer melted are allowed to cool in the next step, as the resin in the resin component constituting the resin particles shrinks to return to its original shape, some of them will three-dimensionally fuse with adjacent resin particles, leaving voids between them.

[0057] Step 3: The molding die that has been heat-treated in step 2 is allowed to cool, and the contents are removed from the molding die to obtain a resin molded product.

[0058] There are no particular limitations on the method for cooling the molding mold and the method for releasing the contents in step 3, and any conventionally known method may be used. For example, the molding mold that was left standing at a predetermined temperature for a predetermined time in step 2 above is allowed to cool in the atmosphere until it reaches approximately room temperature, and the contents after the heat treatment are removed (released) from the molding mold whose surface has previously been treated with a release agent in step 1 above, thereby obtaining a resin molded product.

[0059] Next, the invention of the present application will be specifically explained by showing examples, but the invention of the present application is not limited to these examples. [Example]

[0060] In this Example 1, first, an average molecular weight of 200 × 10 4 200 g of polyethylene particles (Mipelon XM-220 manufactured by Mitsui Chemicals, Inc.) with an average particle size of 30 μm were added, and the kinematic viscosity at 40°C was 650 mm 2 200 g of a mineral oil-based lubricant (Bonnock TS680 manufactured by ENEOS Corporation) with a viscosity of 1 / s was prepared. Five mg of polyethylene particles were weighed and subjected to thermal analysis using a differential scanning calorimeter (DSC214Polymer manufactured by NETZSCH). The melting temperature of the polyethylene particles was found to be around 135.4°C, and the specific heat near this melting temperature was a large 16.740 J / g·K. The results are shown in Figure 1(A).

[0061] Here, for the purpose of performing a more precise thermal analysis, the heat of fusion of a powder sample made of the polyethylene particles was measured in a degassed state by heating it once. 4Five milligrams of polyethylene particles (Mipelon XM-220, manufactured by Mitsui Chemicals, Inc.) with an average particle size of 30 μm were weighed and placed in a sample container. Using a differential scanning calorimeter (NETZSCH DSC214Polymer), the sample was heated from 25°C to 200°C, then cooled to 25°C, and then heated again to 200°C. The powder sample was degassed and the heat of fusion was measured. As shown in [1] of Figure 2, the heat of fusion of the polyethylene particles was a large 166 J / g. The thermal analysis conditions used were: measurement temperature: 25°C to 200°C; measurement atmosphere: nitrogen flow at a flow rate of 100 ml / min; sample container: Concavus Al pan; and reference material: sapphire. From the results of these thermal analyses, it can be determined that the polyethylene particles used in Example 1 are difficult to melt when subjected to heat treatment in the process of producing a resin molded product.

[0062] Next, 40 g of the polyethylene particles and 60 g of mineral oil-based lubricating oil were weighed out (each weighed so that the weight ratio of resin particle component to oil component was 4:6) and placed in a container and mixed using a commercially available stirrer and stir bar. The mixture was placed into an aluminum alloy mold through the raw material inlet and placed in a commercially available heat treatment device. The temperature was raised from room temperature (25 °C) to 190 °C and held there for 30 minutes, then allowed to cool in the heat treatment device until it returned to room temperature. The mixture was then removed from the mold and two flat plate-shaped resin molded products were obtained, each 1.8 mm thick, 30 mm wide, and 30 mm deep with rounded corners. Further molding was performed under the same conditions to obtain a rectangular resin molded product 1 mm thick, 1 mm wide, and 170 mm long, and a spur gear (parallel axis gear)-shaped resin molded product with a tooth width of 8 mm, a reference circle diameter of 30 mm, a tooth tip circle diameter of 32 mm, 30 teeth, and a shaft hole diameter of 8 mm.

[0063] One of the flat resin molded articles obtained in Example 1 was cut lengthwise to a maximum width of approximately 9.6 mm and a maximum depth of approximately 2 mm to prepare a test piece. Observation under an optical microscope revealed that the resin molded article had a dual structure (core-shell structure) inside. Optical microscope images of the test piece are shown in Figures 3(A) and 3(B). The test piece was then stained with osmium oxide and observed again under an optical microscope. As shown in Figures 3(C) and 3(D), the shell portion constituting the outer shell of the resin molded article was not stained with osmium oxide and remained mostly white. Meanwhile, the core portion inside the shell portion was stained with osmium oxide and mostly discolored black. Therefore, it was determined that the shell portion of the resin molded article obtained in Example 1 was primarily composed of polyethylene, and the core portion was primarily composed of lubricating oil. Here, when the flat resin molded product obtained in Example 1 was cut longitudinally to prepare the test piece, no oil component (mineral oil-based lubricating oil in this Example 1) leaked out of the test piece. Therefore, it can be determined that the core also contains a resin component (polyethylene in this Example 1), and that the resin component keeps the oil component present in the core in a fluid state. The conditions used for staining the sample piece with osmium oxide were a 2 wt% aqueous osmium tetroxide solution, a liquid temperature of 60°C, and an immersion time of 2 hours.

[0064] The stained specimen was further broken down into smaller pieces and observed using an X-ray μCT scanner (μCT50, manufactured by Scanco Medical). The shell, which constitutes the outer shell of the resin molded product, was primarily composed of a collection of particulate matter and had a porous structure. Meanwhile, the core, located inside the shell, had almost no voids and was filled with resin components, which appeared to have shapes such as particles, fibers, strings, and spider webs, as well as oil components. Figures 4A and 4B show XY-axis and 3D images of the stained specimen, taken using the X-ray μCT scanner. Figures 4C and 4D show XY-axis and 3D images of the shell of the stained specimen, taken using the X-ray μCT scanner.

[0065] Next, the other flat-plate-shaped resin molded product obtained in Example 1 was cut longitudinally to a maximum width of approximately 1.5 mm and a maximum depth of approximately 1.3 mm to prepare test specimens. The distribution of voids in the resin molded product was observed using an X-ray μCT scanner (μCT50, SCANCO MEDICAL). The results revealed that numerous voids less than 10 μm in size were present, primarily in the shell portion constituting the outer shell of the resin molded product, with an average void diameter of 4.1 μm. Figure 5 shows a 3D void diameter distribution diagram representing the void distribution, and Figure 6 shows a graphical representation of this diagram. From the results of observation using an optical microscope and an X-ray μCT scanner, it can be determined that the resin molded product obtained in Example 1 has a core-shell structure, with the shell portion constituting the outer shell primarily composed of a resin component, and the core portion enclosed within the shell containing both a resin component and an oil component. It can also be determined that the resin component constituting the shell portion contains voids that could serve as flow paths for the oil component.

[0066] Furthermore, a tensile test was conducted on the rectangular resin molded product obtained in Example 1 using a tension-compression testing machine (Shimadzu Corporation's Autograph AGS-J). The stroke (displacement) until the specimen broke was a large value of approximately 316 mm. Figure 7 shows the results of this tensile test. The conditions for this tensile test were a gripper distance of 100 mm and a measurement speed of 10 mm / min.

[0067] A sliding test was then conducted on the spur gear-shaped resin molded product obtained in Example 1, and the sliding properties of the resin molded product were found to be good. Specifically, the resin molded product of Example 1 was mounted on a shaft connected to a commercially available torque meter and rotated at 250 rpm using a motor equipped with a molybdenum steel spur gear of the same size. The time (endurance time) until the torque meter reading (torque) exceeded 2 Nm after one continuous minute was measured. As a result, the endurance time in the test using the resin molded product of Example 1 was 10,000 hours. As a comparison, a similar test was conducted using a commercially available polyacetal spur gear of the same size, with a mineral oil-based lubricant (Bonnock TS680 manufactured by ENEOS Corporation) applied to the surface. The endurance time in the test was 16 hours. The appearance of the resin molded product after this sliding test was observed, and no defects such as cracks or deformation were observed. Furthermore, the spur gear made of polyacetal used as a comparison had a lot of dirt attached to it after the sliding test, which occurs when the surface is scraped, but almost no such dirt or other adhesions were found on the spur gear (resin molded product) after the sliding test of this Example 1. From the results of these tensile tests and sliding tests, it can be determined that the resin molded product obtained in Example 1 has the strength and good sliding properties (lubricity) required for use as parts such as gears and washers to be incorporated into equipment such as industrial machinery, machine tools, and tools, and has the ability to supply lubricating oil to such equipment for a long period of time. [Example]

[0068] In this Example 2, first, an average molecular weight of 200 × 10 4 200 g of polyethylene particles (Mipelon XM-330 manufactured by Mitsui Chemicals, Inc.) with an average particle size of 65 μm were used. 2200 g of liquid paraffin (Hicol K230, manufactured by Kaneda Co., Ltd.) with a viscosity of approximately 1 / s was prepared. Five mg of these polyethylene particles were weighed and subjected to thermal analysis using a differential scanning calorimeter (DSC214Polymer, manufactured by NETZSCH). The melting temperature of the polyethylene particles was approximately 135.5°C, and the specific heat near this melting temperature was as high as 16.002 J / g·K. The results are shown in Figure 1 (B). Here, for the purpose of performing a more precise thermal analysis, the heat of fusion of a powder sample made of the polyethylene particles was measured in a degassed state by heating it once. The thermal analysis method and conditions for the specific heat and heat of fusion were the same as those in Example 1, and therefore will not be described here. As a result, as shown in Figure 2 [2], the heat of fusion of the polyethylene particles was as high as 166.6 J / g. From these thermal analysis results, it can be determined that the polyethylene particles used in Example 2 are difficult to melt when subjected to heat treatment in the process of producing a resin molded product.

[0069] Next, 50 g of the polyethylene particles and 50 g of liquid paraffin were weighed out (each weighed so that the weight ratio of resin particle component to oil component was 5:5) and placed in a container and mixed using a commercially available stirrer and stir bar. The mixture was then placed into an aluminum alloy mold through the raw material inlet and placed in a commercially available heat treatment device. The temperature was raised from room temperature (25 °C) to 220 °C and held there for 30 minutes, after which it was allowed to cool to room temperature in the heat treatment device. The molded product was then removed from the mold to obtain two flat plate-shaped resin molded products measuring 1.8 mm in thickness, 30 mm in width, and 30 mm in depth with rounded corners. Further molding was performed under the same conditions to obtain a rectangular resin molded product measuring 1 mm in thickness, 1 mm in width, and 170 mm in length, and a spur gear (parallel axis gear)-shaped resin molded product measuring 8 mm in tooth width, 30 mm in reference circle diameter, 32 mm in tooth tip circle diameter, 30 teeth, and 8 mm in shaft hole diameter.

[0070] One of the flat resin molded articles obtained in Example 2 was cut lengthwise to a maximum width of about 9.6 mm and a maximum depth of about 2 mm to prepare a test piece, and when observed under an optical microscope, it was found that the resin molded article had a double structure (core-shell structure) inside, although this is not shown. Here, when the flat resin molded article obtained in Example 2 was cut lengthwise to prepare the test piece, no oil component (liquid paraffin in Example 2) leaked out of the test piece, so it can be determined that the core contains a resin component (polyethylene in Example 2) and that the resin component keeps the oil component present in the core in a fluid state.

[0071] Next, the other flat resin molded article obtained in Example 2 was immersed in 96% n-hexane by mass, and then the oil component contained in the resin molded article was replaced three times under atmospheric pressure with 95% industrial ethanol by volume. Observation of the shell portion of the resin molded article after this replacement treatment using an electron microscope revealed that the shell portion was primarily composed of an aggregate of resin particles with an average particle size of approximately 50 μm. More specifically, as shown in Figures 8(A) and 8(B), the shell portion was composed of an aggregate of resin particles with a relatively uniform particle size. The surface layer of the resin particles was partially melted by heat treatment (the heating step during manufacturing), and adjacent resin particles were partially fused and connected to each other. Furthermore, there were voids between the resin particles that could serve as flow paths for the oil component.

[0072] Next, a tensile test was performed on the rectangular resin molded product obtained in Example 2 using a tension / compression testing machine (Autograph AGS-J, manufactured by Shimadzu Corporation). Although not shown in the figure, the stroke (amount of displacement) until the sample broke was large. The tensile test conditions were the same as those in Example 1.

[0073] Furthermore, when a sliding test was conducted on the spur gear-shaped resin molded product obtained in Example 2, the resin molded product exhibited good sliding properties. Specifically, when a sliding test was conducted on the spur gear-shaped resin molded product using the same method and conditions as in Example 1, the resin molded product of Example 2 exhibited a long durability comparable to that of Example 1. Furthermore, when the appearance of the resin molded product was observed after the sliding test, no defects such as cracks or deformation were observed, and almost no adhesion of dust or other material that occurs when the surface is scraped was observed. From the results of these tensile tests and sliding tests, it can be determined that the resin molded product obtained in Example 2 has the strength and good sliding properties (lubricity) required for use as parts such as gears and washers incorporated into equipment such as industrial machinery, machine tools, and tools, and has the ability to supply lubricating oil to such equipment for a long period of time. [Example]

[0074] In this Example 3, the same raw material as in Example 1 was used, and the average molecular weight was 200 × 10 4 50 g of polyethylene particles (Mipelon XM-220 manufactured by Mitsui Chemicals, Inc.) with an average particle size of 30 μm and a kinematic viscosity of 650 mm at 40°C were used. 2 50 g of a mineral oil-based lubricant (Bonnoc TS680 manufactured by ENEOS Corporation) was weighed into a container (each weighed so that the weight ratio of resin particle component to oil component was 5:5), and then mixed using a commercially available stirrer and stir bar. The mixture was placed into an aluminum alloy mold through the raw material inlet and placed in a commercially available heat treatment device. The temperature was raised from room temperature (25°C) to 190°C and held there for 30 minutes, then allowed to cool in the heat treatment device until it returned to room temperature. The mixture was then removed from the mold to obtain two flat resin molded products with a thickness of 4.6 mm, a width of 30 mm, and a depth of 30 mm and rounded corners. Further molding was performed under the same conditions to obtain a rectangular resin molded product with a thickness of 1 mm, a width of 1 mm, and a length of 170 mm, and a spur gear (parallel axis gear)-shaped resin molded product with a tooth width of 8 mm, a reference circle diameter of 30 mm, a tooth tip circle diameter of 32 mm, 30 teeth, and a shaft hole diameter of 8 mm.

[0075] One of the flat resin molded articles obtained in Example 3 was cut longitudinally to a maximum width of approximately 3.3 mm and a maximum depth of approximately 2 mm to obtain a test piece. Observation under an optical microscope revealed that the resin molded article had a dual structure (core-shell structure) inside. Optical microscope images of the test piece are shown in Figures 9(A) and 9(B). When the flat resin molded article obtained in Example 3 was cut longitudinally to prepare the test piece, no oil component (mineral oil-based lubricating oil in Example 3) leaked from the test piece. This indicates that the core contains a resin component (polyethylene in Example 3), and that the resin component retains the oil component present in the core in a fluid state. Furthermore, using the other flat resin molded article obtained in Example 3, the oil component was replaced with ethanol using the same method and conditions as in Example 2. The shell of the resin molded article was then observed under an electron microscope. Although not shown, the shell was composed of an aggregate of resin particles with a relatively uniform particle size. The surface layers of the resin particles were partially melted by the heat treatment, and adjacent resin particles were partially fused and connected to each other. Furthermore, voids that could serve as flow paths for the oil component were present between the resin particles.

[0076] Next, a tensile test was performed on the rectangular resin molded product obtained in Example 3 using a tension-compression testing machine (Shimadzu Corporation's Autograph AGS-J). The stroke (displacement) until the sample broke was a large value of approximately 384 mm. The results of this tensile test are shown in Figure 7. The tensile test conditions were the same as those in Example 1.

[0077] Furthermore, when a sliding test was conducted on the spur gear-shaped resin molded product obtained in Example 3, the resin molded product exhibited good sliding properties. Specifically, when a sliding test was conducted on the spur gear-shaped resin molded product using the same method and conditions as in Example 1, the resin molded product of Example 3 exhibited a long durability comparable to that of Example 1. Furthermore, when the appearance of the resin molded product was observed after the sliding test, no defects such as cracks or deformation were observed, and almost no adhesion of dust or other material that occurs when the surface is scraped was observed. From the results of these tensile tests and sliding tests, it can be determined that the resin molded product obtained in Example 3 has the strength and good sliding properties (lubricity) required for use as parts such as gears and washers incorporated into equipment such as industrial machinery, machine tools, and tools, and has the ability to supply lubricating oil to such equipment for a long period of time. [Example]

[0078] Example 4 differs from Example 3 only in that the amounts of polyethylene particles and mineral oil-based lubricant were changed to 30 g and 70 g, respectively (the weight ratio of resin particle component to oil component was changed to 3:7). Therefore, the method for producing the resin molded product will not be described here.

[0079] One of the flat resin molded articles obtained in Example 4 was cut longitudinally to a maximum width of approximately 3 mm and a maximum depth of approximately 2 mm to obtain a test piece. Observation under an optical microscope revealed that the resin molded article had a dual structure (core-shell structure) inside. (C) and (D) of Figure 9 show optical microscope images of the test piece. Here, when the flat resin molded article obtained in Example 4 was cut longitudinally to prepare the test piece, no oil component (mineral oil-based lubricating oil in Example 4) leaked out of the test piece. This indicates that the core portion also contains a resin component (polyethylene in Example 4), and that the resin component retains the oil component present in the core portion in a fluid state. Furthermore, using the other flat resin molded article obtained in Example 4, the oil component was replaced with ethanol using the same method and conditions as in Example 2. The shell portion of the resin molded article was then observed under an electron microscope. Although not shown, the shell portion was composed of an aggregate of resin particles with a relatively uniform particle size. The surface layers of the resin particles were partially melted by the heat treatment, and adjacent resin particles were partially fused and connected to each other. Furthermore, voids that could serve as flow paths for the oil component were present between the resin particles.

[0080] Next, a tensile test was performed on the rectangular resin molded product obtained in Example 4 using a tension-compression tester (Shimadzu Corporation's Autograph AGS-J). The stroke (displacement) until the sample broke was a large value of approximately 175 mm. The results of this tensile test are shown in Figure 7. The tensile test conditions were the same as those in Example 1.

[0081] Furthermore, when a sliding test was conducted on the spur gear-shaped resin molded product obtained in Example 4, the resin molded product exhibited good sliding properties. Specifically, when a sliding test was conducted on the spur gear-shaped resin molded product using the same method and conditions as in Example 1, the resin molded product of Example 4 exhibited a long durability comparable to that of Example 1. Furthermore, when the appearance of the resin molded product was observed after the sliding test, no defects such as cracks or deformation were observed, and almost no adhesion of dust or other material that occurs when the surface is scraped was observed. From the results of these tensile tests and sliding tests, it can be determined that the resin molded product obtained in Example 4 has the strength and good sliding properties (lubricity) required for use as parts such as gears and washers incorporated into equipment such as industrial machinery, machine tools, and tools, and has the ability to supply lubricating oil to such equipment for a long period of time. [Example]

[0082] Example 5 differs from Example 3 only in that the amounts of polyethylene particles and mineral oil-based lubricant were changed to 20 g and 80 g, respectively (the weight ratio of resin particle component to oil component was changed to 2:8), and the size of the flat resin molded product was changed to "thickness 1.8 mm, width 30 mm, depth 30 mm." Therefore, a description of the manufacturing method of the resin molded product will be omitted.

[0083] One of the flat resin molded articles obtained in Example 5 was cut longitudinally to a maximum width of approximately 2.8 mm and a maximum depth of approximately 2 mm to obtain a test piece. Observation under an optical microscope revealed that the resin molded article had a dual structure (core-shell structure) inside. (E) and (F) of Figure 9 show optical microscope images of the test piece. Here, when the flat resin molded article obtained in Example 5 was cut longitudinally to prepare the test piece, no oil component (mineral oil-based lubricating oil in Example 5) leaked from the test piece. This indicates that the core contains a resin component (polyethylene in Example 5), and that the resin component retains the oil component present in the core in a fluid state. Furthermore, using the other flat resin molded article obtained in Example 5, the oil component was replaced with ethanol using the same method and conditions as in Example 2. The shell of the resin molded article was then observed under an electron microscope. Although not shown, the shell was composed of an aggregate of resin particles with a relatively uniform particle size. The surface layers of the resin particles were partially melted by the heat treatment, and adjacent resin particles were partially fused and connected to each other. Furthermore, voids that could serve as flow paths for the oil component were present between the resin particles.

[0084] Next, a tensile test was performed on the rectangular resin molded product obtained in Example 5 using a tension-compression testing machine (Shimadzu Corporation's Autograph AGS-J). The stroke (displacement) until the sample broke was a large value of approximately 175 mm. Figure 7 shows the results of this tensile test. The tensile test conditions were the same as those in Example 1.

[0085] Furthermore, when a sliding test was conducted on the spur gear-shaped resin molded product obtained in Example 5, the resin molded product exhibited good sliding properties. Specifically, when a sliding test was conducted on the spur gear-shaped resin molded product using the same method and conditions as in Example 1, the resin molded product of Example 5 exhibited a long durability comparable to that of Example 1. Furthermore, when the appearance of the resin molded product was observed after the sliding test, no defects such as cracks or deformation were observed, and almost no adhesion of dust or other material that occurs when the surface is scraped was observed. From the results of these tensile tests and sliding tests, it can be determined that the resin molded product obtained in Example 5 has the strength and good sliding properties (lubricity) required for use as parts such as gears and washers incorporated into equipment such as industrial machinery, machine tools, and tools, and has the ability to supply lubricating oil to such equipment for a long period of time. [Example]

[0086] In this Example 6, the average molecular weight is 200×10 4 50 g of polyethylene particles (Mipelon XM-220 manufactured by Mitsui Chemicals, Inc.) with an average particle size of 30 μm were used. 2 The only difference from Example 3 is that the test was conducted using 50 g of liquid paraffin (Hicol K230 manufactured by Kaneda Co., Ltd.) with a viscosity of around / s (changing the type of oil component). Therefore, the description of the manufacturing method for the resin molded article will be omitted.

[0087] One of the flat resin molded articles obtained in Example 6 was cut lengthwise to a maximum width of approximately 3 mm and a maximum depth of approximately 2 mm to prepare a test piece. Observation with an optical microscope revealed that the resin molded article had a dual structure (core-shell structure) inside, although not shown. When the flat resin molded article obtained in Example 6 was cut lengthwise to prepare the test piece, no oil component (liquid paraffin in Example 6) leaked from the test piece. This indicates that the core contains a resin component (polyethylene in Example 6), which retains the oil component present in the core in a fluid state. Furthermore, using the other flat resin molded article obtained in Example 6, the oil component was replaced with ethanol using the same method and conditions as in Example 2. The shell of the resin molded article was then observed with an electron microscope. Although not shown, the shell was composed of an aggregate of resin particles with a relatively uniform particle size. The surface layers of the resin particles were partially melted by the heat treatment, and adjacent resin particles were partially fused and connected to each other. Furthermore, voids that could serve as flow paths for the oil component were present between the resin particles.

[0088] Next, a tensile test was performed on the rectangular resin molded product obtained in Example 6 using a tension-compression testing machine (Shimadzu Corporation's Autograph AGS-J). The stroke (displacement) until the sample broke was a large value of approximately 593 mm. The results of this tensile test are shown in Figure 7. The tensile test conditions were the same as those in Example 1.

[0089] Furthermore, when a sliding test was conducted on the spur gear-shaped resin molded product obtained in Example 6, the resin molded product exhibited good sliding properties. Specifically, when a sliding test was conducted on the spur gear-shaped resin molded product using the same method and conditions as in Example 1, the resin molded product of Example 6 exhibited a long durability comparable to that of Example 1. Furthermore, when the appearance of the resin molded product was observed after the sliding test, no defects such as cracks or deformation were observed, and almost no adhesion of dust or other material that occurs when the surface is scraped was observed. From the results of these tensile tests and sliding tests, it can be determined that the resin molded product obtained in Example 6 has the strength and good sliding properties (lubricity) required for use as parts such as gears and washers incorporated into equipment such as industrial machinery, machine tools, and tools, and has the ability to supply lubricating oil to such equipment for a long period of time. [Example]

[0090] In this Example 7, first, an average molecular weight of 8×10 4 200g of polyacetal particles with an average particle size of 40μm and a kinematic viscosity of 650mm at 40℃ 2 200 g of a mineral oil-based lubricant (Bonnock TS680 manufactured by ENEOS Corporation) with a viscosity of 1 / s was prepared. Five mg of these polyacetal particles were weighed and subjected to thermal analysis using a differential scanning calorimeter (DSC214Polymer manufactured by NETZSCH). The melting temperature of the polyacetal particles was found to be around 165.0°C, and the specific heat near this melting temperature was a large 22.496 J / g·K. The results are shown in Figure 10(A).

[0091] Here, for the purpose of performing a more precise thermal analysis, the heat of fusion of a powder sample made of the polyacetal particles was measured in a degassed state by heating it once. 4Five milligrams of polyacetal particles with an average particle size of 40 μm were weighed and placed in a sample container. Using a differential scanning calorimeter (NETZSCH DSC214Polymer), the sample was heated from 25°C to 220°C, then cooled to 25°C, and then heated again to 220°C. The powder sample consisting of the polyacetal particles was degassed and the heat of fusion was measured. As shown in [1] of Figure 11, the heat of fusion of the polyethylene particles was a large 177 J / g. The conditions for these thermal analyses were: measurement temperature 25°C to 220°C, measurement atmosphere nitrogen flow at a flow rate of 100 ml / min, sample container Concavus Al pan, and reference material sapphire. From these thermal analysis results, it can be determined that the polyacetal particles used in Example 7 are difficult to melt when subjected to heat treatment in the process of manufacturing a resin molded product.

[0092] Next, 40 g of the polyacetal particles and 60 g of mineral oil-based lubricating oil were weighed out (each weighed so that the weight ratio of resin particle component to oil component was 4:6) and placed in a container and mixed using a commercially available stirrer and stir bar. The mixture was placed into an aluminum alloy mold through the raw material inlet and placed in a commercially available heat treatment device. The temperature was raised from room temperature (25 °C) to 190 °C and held there for 30 minutes, and then allowed to cool in the heat treatment device until it returned to room temperature. The mixture was then removed from the mold and two flat resin molded products were obtained, each 1.8 mm thick, 30 mm wide, and 30 mm deep with rounded corners. Further molding was performed under the same conditions to obtain a rectangular resin molded product 1 mm thick, 1 mm wide, and 170 mm long, and a spur gear (parallel axis gear)-shaped resin molded product with a tooth width of 8 mm, a reference circle diameter of 30 mm, a tooth tip circle diameter of 32 mm, 30 teeth, and a shaft hole diameter of 8 mm.

[0093] One of the flat resin molded articles obtained in Example 7 was cut lengthwise to a maximum width of approximately 5 mm and a maximum depth of approximately 2 mm to prepare a test piece. Observation under an optical microscope revealed that the resin molded article had a double structure (core-shell structure) inside, although not shown. When the flat resin molded article obtained in Example 7 was cut lengthwise to prepare the test piece, no oil component (mineral oil-based lubricating oil in Example 7) leaked out of the test piece. This indicates that the core contains a resin component (polyacetal in Example 7), and that the resin component retains the oil component present in the core as a fluid. Furthermore, using the other flat resin molded article obtained in Example 7, the oil component was replaced with ethanol using the same method and conditions as in Example 2. The shell of the resin molded article was then observed under an electron microscope. Although not shown, the shell was composed of an aggregate of resin particles with a relatively uniform particle size. The surface layers of the resin particles were partially melted by the heat treatment, and adjacent resin particles were partially fused and connected to each other. Furthermore, voids that could serve as flow paths for the oil component were present between the resin particles.

[0094] Next, a tensile test was performed on the rectangular resin molded product obtained in Example 7 using a tension and compression testing machine (Autograph AGS-J, manufactured by Shimadzu Corporation). Although not shown in the figure, the stroke (amount of displacement) until the sample broke was large. The tensile test conditions were the same as those in Example 1.

[0095] Furthermore, when a sliding test was conducted on the spur gear-shaped resin molded product obtained in Example 7, the resin molded product exhibited good sliding properties. Specifically, when a sliding test was conducted on the spur gear-shaped resin molded product using the same method and conditions as in Example 1, the resin molded product of Example 7 exhibited a long durability comparable to that of Example 1. Furthermore, when the appearance of the resin molded product was observed after the sliding test, no defects such as cracks or deformation were observed, and almost no adhesion of dust or other material that occurs when the surface is scraped was observed. From the results of these tensile tests and sliding tests, it can be determined that the resin molded product obtained in Example 7 has the strength and good sliding properties (lubricity) required for use as parts such as gears and washers incorporated into equipment such as industrial machinery, machine tools, and tools, and has the ability to supply lubricating oil to such equipment for a long period of time. [Example]

[0096] In this Example 8, the average molecular weight is 8×10 4 The average molecular weight was 8 × 10 4 The only difference from Example 7 is that polyacetal particles having an average particle size of 20 μm were used. Therefore, the method and conditions for thermal analysis regarding the specific heat and heat of fusion, and the method for producing the resin molded product will be omitted.

[0097] The polyacetal particles used in Example 8 had a melting temperature of around 163.9°C and a high specific heat of 21.854 J / g·K around the melting temperature. The results are shown in FIG. 10(B). Furthermore, as shown in FIG. 11[2], the polyacetal particles had a high heat of fusion of 193.7 J / g. From these thermal analysis measurement results, it can be determined that the polyacetal particles used in Example 8 are difficult to melt when subjected to heat treatment in the process of producing a resin molded product.

[0098] Next, one of the flat resin molded articles obtained in Example 8 was cut lengthwise to a maximum width of approximately 5 mm and a maximum depth of approximately 2 mm to prepare a test piece. Observation under an optical microscope revealed that the resin molded article had a double structure (core-shell structure) inside, although not shown. When the flat resin molded article obtained in Example 8 was cut lengthwise to prepare the test piece, no oil component (mineral oil-based lubricating oil in Example 8) leaked out of the test piece. This indicates that the core contains a resin component (polyacetal in Example 8), and that the resin component retains the oil component present in the core as a fluid. Furthermore, using the other flat resin molded article obtained in Example 8, the oil component was replaced with ethanol using the same method and conditions as in Example 2. The shell of the resin molded article was then observed under an electron microscope. Although not shown, the shell was composed of an aggregate of resin particles with a relatively uniform particle size. The surface layers of the resin particles were partially melted by the heat treatment, and adjacent resin particles were partially fused and connected to each other. Furthermore, voids that could serve as flow paths for the oil component were present between the resin particles.

[0099] Next, a tensile test was performed on the rectangular resin molded product obtained in Example 8 using a tension-compression testing machine (Autograph AGS-J, manufactured by Shimadzu Corporation). Although not shown in the figure, the stroke (amount of displacement) until the sample broke was large. The tensile test conditions were the same as those in Example 1.

[0100] Furthermore, when a sliding test was conducted on the spur gear-shaped resin molded product obtained in Example 8, the resin molded product exhibited good sliding properties. Specifically, when a sliding test was conducted on the spur gear-shaped resin molded product using the same method and conditions as in Example 1, the resin molded product of Example 8 exhibited a long durability comparable to that of Example 1. Furthermore, when the appearance of the resin molded product was observed after the sliding test, no defects such as cracks or deformation were observed, and almost no adhesion of dust or other material that occurs when the surface is scraped was observed. From the results of these tensile tests and sliding tests, it can be determined that the resin molded product obtained in Example 8 has the strength and good sliding properties (lubricity) required for use as parts such as gears and washers incorporated into equipment such as industrial machinery, machine tools, and tools, and has the ability to supply lubricating oil to such equipment for a long period of time. [Example]

[0101] In Example 9, 3 g of 1-menthol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was first added to a solution having a kinematic viscosity of 13.6 mmHg at 37.8°C. 2 57 g of liquid paraffin (Hicol K230, manufactured by Kaneda Co., Ltd.) with an average molecular weight of about 1 / s was weighed out (each weighed so that the content of the secondary components in the oil component was 5 wt%) and placed in a container, and then mixed using a commercially available stirrer and stir bar. Next, 57 g of liquid paraffin with an average molecular weight of about 1 / s was weighed out (each weighed so that the content of the secondary components in the oil component was 5 wt%) and placed in a container, and then mixed using a commercially available stirrer and stirrer. 4 40 g of polyethylene particles (Mipelon XM-220, manufactured by Mitsui Chemicals, Inc.) with an average particle size of 30 μm were weighed out (weighed so that the weight ratio of resin particle component to oil component was 4:6) and then further mixed using a stirrer and stir bar. The mixture was placed into an aluminum alloy mold through the raw material inlet and placed in a commercially available heat treatment device. The temperature was raised from room temperature (25°C) to 190°C and held there for 2 minutes, then allowed to cool to room temperature in the heat treatment device. The mixture was then removed from the mold to obtain two flat resin molded products measuring 1.8 mm thick, 30 mm wide, and 30 mm deep with rounded corners. Further molding was performed under the same conditions to obtain a circular resin molded product measuring 30 mm in diameter and 7 mm thick.

[0102] One of the flat resin molded articles obtained in Example 9 was cut lengthwise to a maximum width of approximately 5 mm and a maximum depth of approximately 2 mm to prepare a test piece. Observation under an optical microscope revealed that the resin molded article had a dual structure (core-shell structure) inside, although not shown. When the flat resin molded article obtained in Example 9 was cut lengthwise to prepare the test piece, no oil component (a mixture of liquid paraffin and l-menthol in this Example 9) leaked out of the test piece. This indicates that the core contains a resin component (polyethylene in this Example 9), which maintains the oil component present in the core in a fluid state. Furthermore, using the other flat resin molded article obtained in Example 9, the oil component was replaced with ethanol using the same method and conditions as in Example 2. The shell of the resin molded article was then observed under an electron microscope. Although not shown, the shell was composed of an aggregate of resin particles with a relatively uniform particle size. The surface layers of the resin particles were partially melted by the heat treatment, and adjacent resin particles were partially fused and connected to each other. Furthermore, voids that could serve as flow paths for the oil component were present between the resin particles.

[0103] Next, an olfactory sensory test was conducted on a panel of five people using the disk-shaped resin molded article obtained in Example 9. Specifically, the resin molded article obtained in Example 9 was first placed in a glass sample bottle and left to stand in a cool, dark place with the lid open. The odor was then checked every seven days, and the period during which four out of the five people perceived the aroma as fragrant (odor duration) was measured. As a result, the odor duration of the resin molded article of Example 9 was 420 days.

[0104] For comparison, a commercially available diatomaceous earth plate of the same size was prepared, and 3 g of a perfume oil (1-menthol (Fujifilm Wako Pure Chemical Industries, Ltd.) with a kinematic viscosity of 13.6 mm at 37.8°C) prepared in the same manner as in Example 9 was placed on the plate. 257 g of liquid paraffin (Hicol K230 by Kaneda Co., Ltd.) with a temperature of around 1 / s was weighed out and placed in a container, and then mixed using a commercially available stirrer and stir bar. The mixture was then immersed for 3 hours and placed on a stainless steel flat sieve to drain off the oil. The mixture was then placed in a glass sample bottle of the same size as in Example 9 and subjected to an olfactory sensory test under the same conditions as in Example 9. The odor persisted for 70 days. From this olfactory sensory test, it can be determined that the resin molded product of Example 9 has the ability to emit a fragrance into the surrounding area for a long period of time, compared to conventional technology. [Example]

[0105] In Example 10, 2.4 g of dl-camphor (manufactured by Kanto Chemical Co., Ltd.), 0.6 g of dichlorobenzene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and a solution having a kinematic viscosity of 13.6 mmHg at 37.8°C were first used. 2 57 g of liquid paraffin (Hicol K230, manufactured by Kaneda Co., Ltd.) with an average molecular weight of about 1 / s was weighed out (each weighed so that the total content of the minor components in the oil component was 5 wt%) and placed in a container, and then mixed using a commercially available stirrer and stir bar. Next, 57 g of liquid paraffin with an average molecular weight of about 1 / s was weighed out (each weighed so that the total content of the minor components in the oil component was 5 wt%) and placed in a container, and then mixed using a commercially available stirrer and stirrer. 4 40 g of polyethylene particles (Mipelon XM-220, manufactured by Mitsui Chemicals, Inc.) with an average particle size of 30 μm were weighed out (weighed so that the weight ratio of resin particle component to oil component was 4:6) and then further mixed using a stirrer and stir bar. The mixture was placed into an aluminum alloy mold through the raw material inlet and placed in a commercially available heat treatment device. The temperature was raised from room temperature (25°C) to 190°C and held there for 2 minutes, then allowed to cool to room temperature in the heat treatment device. The mixture was then removed from the mold to obtain two flat resin molded products measuring 1.8 mm thick, 30 mm wide, and 30 mm deep with rounded corners. Further molding was performed under the same conditions to obtain a circular resin molded product measuring 30 mm in diameter and 7 mm thick.

[0106] One of the flat resin molded articles obtained in Example 10 was cut lengthwise to a maximum width of approximately 5 mm and a maximum depth of approximately 2 mm to prepare a test piece. Observation with an optical microscope revealed that the resin molded article had a dual structure (core-shell structure) inside, although not shown. When the flat resin molded article obtained in Example 10 was cut lengthwise to prepare the test piece, no oil component (a mixture of liquid paraffin, dl-camphor, and dichlorobenzene in this Example 10) leaked out of the test piece. This indicates that the core contains a resin component (polyethylene in this Example 10), which maintains the oil component present in the core in a fluid state. Furthermore, using the other flat resin molded article obtained in Example 10, the oil component was replaced with ethanol using the same method and conditions as in Example 2. The shell of the resin molded article was then observed with an electron microscope. Although not shown, the shell was composed of an aggregate of resin particles with a relatively uniform particle size. The surface layers of the resin particles were partially melted by the heat treatment, and adjacent resin particles were partially fused and connected to each other. Furthermore, voids that could serve as flow paths for the oil component were present between the resin particles.

[0107] Next, an evaluation test of the insect repellent component release into the ambient air was conducted using the disc-shaped resin molded article obtained in Example 10. Specifically, the resin molded article obtained in Example 10 was first placed in a brown glass sample bottle and left in a cool, dark place with the lid closed. Then, every seven days, the lid was opened and the air in the sample bottle was removed with a gas-tight syringe. The period during which the insect repellent components (dl-camphor and dichlorobenzene) were detected in the air in the sample bottle (the insect repellent component release period) was measured using a commercially available gas chromatograph mass spectrometer. After the measurement, the lid was left open for approximately three hours to allow air to be exchanged in the sample bottle, and then the lid was closed and the bottle was left in a cool, dark place again until the next measurement. As a result, the insect repellent component release period for the resin molded article of Example 10 was 616 days. The conditions for the test to evaluate the dissipation of the insect repellent ingredient into the ambient air were as follows: a capillary column for volatile organic compounds, column temperature held at 40°C for 4 minutes, then heated to 250°C at a rate of 10°C / min and held there for 5 minutes, interface temperature of 250°C, ion source temperature of 220°C, ionization energy of 70 eV, and carrier gas of helium with a flow rate of 1 mL / min.

[0108] For comparison, a commercially available diatomaceous earth plate of the same size was prepared and coated with an oil containing an insect repellent component prepared in the same manner as in Example 10 (2.4 g of dl-camphor (Kanto Chemical Co., Ltd.), 0.6 g of dichlorobenzene (Fujifilm Wako Pure Chemical Industries, Ltd.), and a kinetic viscosity of 13.6 mmHg at 37.8°C). 2 57 g of liquid paraffin (Hicol K230 by Kaneda Co., Ltd.) with a viscosity of about 1 / s was weighed out and placed in a container, and then mixed using a commercially available stirrer and stir bar. The mixture was then immersed for 3 hours in the mixture, placed on a stainless steel flat sieve to drain off the oil, and placed in a brown glass sample bottle of the same size as in Example 10. An evaluation test of the insect repellent component's release into the ambient air was conducted under the same conditions as in Example 10, and the insect repellent component release period was 42 days. From this evaluation test of the insect repellent component's release into the ambient air, it can be determined that the resin molded product of Example 10 has the potential to exert an insect repellent effect on clothing, etc. for a longer period of time than conventional technology. Comparative Example

[0109] In this comparative example, first, the average molecular weight is 6 × 10 4 200g of polyphenylene sulfide (PPS) particles with an average particle size of 40μm and a kinematic viscosity of 650mm at 40℃ 2 200 g of a mineral oil-based lubricant (Bonnock TS680 manufactured by ENEOS Corporation) with a viscosity of 1 / s was prepared. Five mg of the polyphenylene sulfide particles were weighed and subjected to thermal analysis using a differential scanning calorimeter (DSC214Polymer manufactured by NETZSCH). The melting temperature of the polyphenylene sulfide particles was found to be around 264.2°C, and the specific heat around this temperature was a small 3.284 J / g·K. The results are shown in Figure 12.

[0110] Here, for the purpose of performing a more precise thermal analysis, the heat of fusion of a powder sample made of the polyphenylene sulfide particles was measured in a degassed state by heating it once. 4 Five milligrams of polyphenylene sulfide particles with an average particle size of 40 μm were weighed out and placed in a sample container. Using a differential scanning calorimeter (NETZSCH DSC214Polyma), the sample was heated from 25°C to 330°C, then cooled to 25°C, and then heated again to 330°C. The heat of fusion of the powder sample was then measured by degassing the polyphenylene sulfide particles. As shown in Figure 13, the heat of fusion of the polyphenylene sulfide particles was a small value of 28.86 J / g. The conditions for these thermal analyses were: measurement temperature: 25°C to 330°C; measurement atmosphere: nitrogen flow at a flow rate of 100 ml / min; sample container: Concavus Al pan; and reference material: sapphire. From the results of these thermal analyses, it can be determined that the polyphenylene sulfide particles used in this comparative example are easily melted when subjected to heat treatment in the process of producing a resin molded product.

[0111] Next, 40 g of the polyphenylene sulfide particles and 60 g of mineral oil-based lubricating oil were weighed out (each weighed so that the weight ratio of resin particle component to oil component was 4:6) and placed in a container and mixed using a commercially available stirrer and stir bar. The mixture was placed into an aluminum alloy mold through the raw material inlet and placed in a commercially available heat treatment device. The temperature was raised from room temperature (25 °C) to 290 °C and held there for 30 minutes, and then allowed to cool to room temperature in the heat treatment device. The mixture was then removed from the mold to obtain two flat resin molded products with a thickness of 1.8 mm, a width of 30 mm, and a depth of 30 mm and rounded corners. Further molding was performed under the same conditions to obtain a resin molded product in the shape of a spur gear (parallel axis gear) with a tooth width of 8 mm, a reference circle diameter of 30 mm, a tooth tip circle diameter of 32 mm, 30 teeth, and a shaft hole diameter of 8 mm.

[0112] Next, one of the flat resin molded articles obtained in this comparative example was cut longitudinally to a maximum width of approximately 5 mm and a maximum depth of approximately 2 mm to form a test piece. Observation under an optical microscope revealed that the resin molded article had a double structure (core-shell structure) inside, although not shown. When the flat resin molded article obtained in this comparative example was cut longitudinally to create the test piece, no oil component (mineral oil-based lubricating oil in this comparative example) leaked from the test piece. This indicates that the core contains a resin component (polyphenylene sulfide in this comparative example), and that the resin component retains the oil component present in the core as a fluid. Furthermore, using the other flat resin molded article obtained in this comparative example, the oil component was replaced with ethanol using the same method and conditions as in Example 2. The shell of the resin molded article was then observed under an electron microscope. Although not shown, the shell contained almost no voids, and the voids that did exist were very small, with an average void diameter of less than 0.3 μm. In conclusion, most of the polyphenylene sulfide particles used in this comparative example were melted to the inside by heat treatment, forming a membrane-like (or layer-like) shell portion with very small voids remaining in some areas, and there were almost no voids in the shell portion that could serve as stable flow paths for the oil components.

[0113] Furthermore, a sliding test was conducted on the spur gear-shaped resin molded product obtained in this comparative example using the same method and conditions as in Example 1. The durability of the resin molded product of this comparative example was equivalent to that of the polyacetal spur gear used as a comparison in Example 1. Furthermore, when the appearance of the resin molded product after this sliding test was observed, a large amount of debris was found to be attached, which occurs when the surface is scraped, etc. From the results of this sliding test, it can be concluded that the resin molded product obtained in this comparative example does not have the ability to supply lubricating oil for long periods of time to equipment such as industrial machinery, machine tools, and power tools. [Industrial Applicability]

[0114] The invention of the present application can be used in industrial machinery, machine tools, tools, and the like that require periodic supply of lubricating oil. More specifically, it can be suitably used as parts for motors, gearboxes, and bearings in these devices. The invention of the present application can also be suitably used as products such as insect repellent rings containing fragrances and / or insect repellent ingredients that, when worn on the wrist or ankle, emit a fragrant fragrance and provide effects such as protecting the human body from pests. The invention of the present application can also be suitably used as products such as insect repellent sheets that protect clothing from pests.

Claims

1. It is composed of resin and oil components. The weight ratio of the resin component to the oil component is 1:9 to 9:1, The molecular weight of the resin contained in the resin component is 7 × 10 ４ ~700 x 10 ４ and The device has a shell portion that forms an outer shell and a core portion that is enclosed by the shell portion, the shell portion is formed by connecting portions of the surface layers of resin particles made of a resin component by fusing together to form voids that serve as flow paths for the oil component, The core portion contains a resin component and an oil component, The resin molded article is characterized in that the oil component contained in the core portion seeps out to the surface over a long period of time through voids in the shell portion.

2. 2. The resin molded article according to claim 1, wherein the specific heat at the melting temperature of the resin particles is 5 J / g·K to 30 J / g·K.

3. 3. The resin molded product according to claim 1, wherein the resin particles have an average particle size of 1 μm to 200 μm.

4. The thickness of the shell portion is 50 μm to 10×10 ３ 3. The resin molded article according to claim 1, wherein the thickness of the resin molded article is 1 μm.

5. 3. The resin molded product according to claim 1, wherein the resin contained in the resin component is at least one selected from the group consisting of polyethylene, polyacetal, polyethylene glycol, and ABS.

6. 3. The resin molded article according to claim 1, wherein the oil component comprises one or more selected from the group consisting of paraffin oil, naphthenic oil, silicone oil, α-olefin oil, jojoba oil, and olive oil.

7. The kinematic viscosity of the oil component at 37.8°C to 40°C is 5mm ２ / s ~ 750 mm ２ 3. The resin molded article according to claim 1, wherein the tensile strength is 1 / s.

8. 3. The resin molded product according to claim 1, wherein the resin component includes a coloring matter or a pigment.

9. 3. The resin molded article according to claim 1, wherein the oil component comprises at least one selected from the group consisting of an antioxidant, a corrosion inhibitor, an extreme pressure agent, a thickener, a fragrance, and an insect repellent.

10. 2. The method for producing a resin molded product according to claim 1, comprising the following steps 1 to 3: Step 1: Molecular weight 7 x 10 ４ ~700 x 10 ４ Resin particles made of a resin component containing the resin of the above and an oil component are mixed in a weight ratio of 1:9 to 9:1, and the mixture is poured into a mold. Step 2: The molding die containing the resin particles and oil component is heated to 140°C to 360°C and left to stand for 10 seconds to 50 minutes. Step 3: The mold is left to cool after standing, and the contents are removed from the mold to obtain a resin molded product.

11. The method for producing a resin molded product according to claim 10, wherein the specific heat at the melting temperature of the resin particles is 5 J / g·K to 30 J / g·K.

12. The method for producing a resin molded product according to claim 10 or 11, wherein the resin particles have an average particle size of 1 μm to 200 μm.

13. The kinematic viscosity of the oil component at 37.8°C to 40°C is 5mm ２ / s ~ 750 mm ２ The method for producing a resin molded article according to claim 10 or 11, wherein the ratio of the molten metal to the total mass of the resin molded article is 1 / s.

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