Method for manufacturing recycled resin compositions, resin molded products, resin housings, and electronic devices.

Abstract

The object of the present invention is to provide a method for producing a recycled resin composition with excellent impact strength using PCR material as a raw material, a resin molded product formed from the recycled resin composition, a resin housing containing the resin molded product, and an electronic device equipped with the resin housing. [Solution] A method for manufacturing a recycled resin composition, comprising the steps of: controlling the particle size by at least grinding the PCR material; calculating the excess grinding of the PCR material, or calculating the excess shredding of the PCR material by shredding the PCR material; estimating the impact strength of the PCR material from the excess grinding or shredding of the PCR material; and adjusting the impact strength of the recycled resin composition based on the estimated impact strength of the PCR material, wherein the impact strength of the recycled resin composition is adjusted based on correlation information between the excess grinding or shredding of the PCR material and the impact strength of the PCR material, which has been prepared in advance.

Description

[Technical Field]

[0001] This invention relates to a method for producing a recycled resin composition, a resin molded product, a resin housing, and electronic equipment. More specifically, it relates to a method for producing a recycled resin composition with excellent impact strength using PCR material as a raw material. [Background technology]

[0002] Today, from an environmental protection perspective, there is a desire to increase the utilization rate of recycled resin-containing materials that have been used in products such as molded resin products, resin casings, and electronic devices, and then recovered after disposal. Technological innovation and production are being advanced to achieve this. Hereinafter, "recycled resin-containing materials" will also be referred to as "PCR (Post-Consumer Recycled) materials."

[0003] However, it is required that PCR materials not only be environmentally friendly but also that quality be guaranteed. For example, Patent Document 1 discloses a technology for manufacturing a recycled resin composition using PCR materials obtained by crushing molded products made of polycarbonate resin, but there was room for improvement in order to produce a higher quality product. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-245756 [Overview of the project] [Problems that the invention aims to solve]

[0005] The PCR material used as raw material is subjected to processes such as crushing or shredding, followed by the addition of additives, before being used as a recycled resin composition. However, recycled resin compositions made from PCR material tend to have variations in quality, making it difficult to guarantee consistent quality.

[0006] This is thought to be due to the influence of various factors, such as the fact that the grade of resin and additives contained in the PCR material differ from one original material to another, the degree of deterioration due to use and aging is not constant, and the mixing ratio of these materials fluctuates.

[0007] When manufacturing recycled resin compositions using PCR material as a raw material, for example, the PCR material is crushed, then washed, and then mixed with other additives.

[0008] Generally, virgin resin compositions are prepared and used by adding various additives to virgin material to achieve the desired physical properties. The same applies to recycled resin compositions as described above; various additives that have been developed exclusively for virgin material are added during the manufacturing of the recycled resin composition.

[0009] However, in recycled resin compositions, the quality of the raw PCR material fluctuates, and unless the type and amount of additives are adjusted accordingly, it is impossible to consistently achieve the target quality. On the other hand, adding too many additives not only increases unnecessary costs because additives are more expensive than the resin itself, but also leads to adverse effects. This is because there is a common trade-off: increasing toughness with additives decreases rigidity, and increasing flame retardants decreases toughness.

[0010] Based on the above, there are various problems in the production of recycled resin compositions using PCR materials as raw materials, and currently, the production of such recycled resin compositions requires a complex process. This is one of the factors hindering the widespread adoption of recycled resin compositions, along with low quality and quality variability, and is a cause of high costs. Therefore, there is a need to produce high-quality recycled resin compositions using a simpler process.

[0011] This invention has been made in view of the above-mentioned problems and circumstances, and its objective is to provide a method for producing a recycled resin composition with excellent impact strength using PCR material as a raw material, a resin molded product formed from the recycled resin composition, a resin housing containing the resin molded product, and an electronic device equipped with the resin housing. [Means for solving the problem]

[0012] The inventors of the present invention have discovered that the above problems can be solved by easily estimating the impact strength of the PCR material used as a raw material and appropriately adjusting the impact strength of the recycled resin composition based on this estimation, and have arrived at the present invention. In other words, the above-mentioned problems according to the present invention are solved by the following means.

[0013] 1. A method for producing a recycled resin composition, The aforementioned recycled resin composition uses PCR material as a raw material, The PCR material is ground to control the particle size, A step of calculating the excess amount of crushing of the PCR material, or a step of shredding the PCR material and calculating the excess amount of shredding of the PCR material, A step of estimating the impact strength of the PCR material from the degree of excessive crushing or shredding of the PCR material, The process includes a step of adjusting the impact strength of the recycled resin composition based on the estimated impact strength of the PCR material, The impact strength of the recycled resin composition is adjusted based on correlation information between the excess crushing or shredding of the PCR material prepared in advance and the impact strength of the PCR material. A method for producing a recycled resin composition characterized by the above.

[0014] 2. The excess of the crushing or shredding of the PCR material is calculated based on at least one of the following: the particle size of the crushed PCR material or the recovery rate of the crushed or shredded PCR material. A method for producing the recycled resin composition according to paragraph 1, characterized by the above.

[0015] 3. The pulverized material of the PCR material is in the form of flakes. The method for producing a recycled resin composition according to claim 1, characterized in that.

[0016] 4. The shredded material of the PCR material is in the form of pellets. The method for producing a recycled resin composition according to claim 1, characterized in that.

[0017] 5. In the step of adjusting the impact strength of the recycled resin composition, at least an impact modifier is added as an additive, The impact strength in the recycled resin composition is adjusted by the amount of the impact modifier. The method for producing a recycled resin composition according to any one of claims 1 to 4, characterized in that.

[0018] 6. The PCR material contains an ABS resin, In the step of adjusting the impact strength of the recycled resin composition, either at least an impact modifier other than the virgin ABS resin composition or the virgin ABS resin composition is added as an additive. The method for producing a recycled resin composition according to claim 5, characterized in that.

[0019] 7. A resin molded product obtained by molding a recycled resin composition produced by the production method according to claim 5.

[0020] 8. Including the resin molded product according to claim 7. A resin housing, characterized in that.

[0021] 9. An electronic device comprising the resin housing according to claim 8. A resin housing, characterized in that.

Advantages of the Invention

[0022] The present invention provides a method for producing a recycled resin composition with excellent impact strength using PCR material as a raw material, a molded resin product formed from the recycled resin composition, a resin housing containing the molded resin product, and an electronic device equipped with the resin housing. Although the mechanism by which the effects of this invention manifest or the mechanism of action are not yet clear, we speculate as follows.

[0023] As mentioned above, recycled resin compositions are required to be of high quality and manufactured through simpler processes.

[0024] In the manufacturing process of recycled resin compositions, there is generally a step in which the PCR material, which is the raw material, is first crushed into flakes of a certain particle size until they can pass through a screen mesh. Then, the crushed flakes undergo a washing process and a material sorting process based on specific gravity and electrostatic properties, which are set up and adjusted according to the condition of the PCR material, such as contamination and constituent materials, to become highly purified PCR material flakes. These highly purified flakes are further crushed, pelletized after melt-kneading, or have additives added to the crushed product or pellets and then pelletized after melt-kneading to become recycled resin compositions, which are raw materials for molding.

[0025] In the process described above, the lower the impact strength of the PCR material used as raw material, the more likely it is to be excessively pulverized, resulting in the generation of fragments and fine powder that are significantly smaller than the mesh size of the screen mesh and are lost.

[0026] Furthermore, in the manufacturing process of recycled resin compositions, there is a step in which crushed PCR material is melt-kneaded to create strands, and these strands are fed at a constant speed through a high-speed rotating metal blade to be shredded into pellets of a certain shape and size.

[0027] In the process described above, the lower the impact strength of the PCR material used as raw material, the more likely it is that fine powder will be lost during strand shredding. In other words, if a material with a low average impact strength is used, the size distribution of the pulverized material obtained after the same grinding process will be biased towards smaller particles, and more fine powder will be lost after the same grinding and shredding process.

[0028] It is presumed that by using this causal-based correlation, the average impact strength of the PCR material used can be estimated, and the appropriate type and amount of additives can be selected to produce a high-quality recycled resin composition. [Brief explanation of the drawing]

[0029] [Figure 1] Graph showing the relationship between the average mass per coarsely ground flake and impact strength. [Figure 2] Graph showing the relationship between the average mass per coarsely ground flake and impact strength. [Figure 3] Graph showing the relationship between the recovery rate of re-pulverized flakes and impact strength. [Figure 4] Graph showing the relationship between pellet recovery rate and impact strength. [Modes for carrying out the invention]

[0030] The present invention relates to a method for producing a recycled resin composition, wherein the recycled resin composition is made from PCR material, and comprises the steps of: controlling the particle size by at least grinding the PCR material; calculating the excess grinding of the PCR material, or calculating the excess shredding of the PCR material by shredding the PCR material; estimating the impact strength of the PCR material from the excess grinding or shredding of the PCR material; and adjusting the impact strength of the recycled resin composition based on the estimated impact strength of the PCR material, wherein the impact strength of the recycled resin composition is adjusted based on correlation information between the excess grinding or shredding of the PCR material and the impact strength of the PCR material, which has been prepared in advance. This feature is a technical feature common to or corresponding to each of the embodiments (appearances) described below.

[0031] The present invention, its components, and embodiments and models for carrying out the present invention will be described in detail below. In this application, "~" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0032] While the advantages and features provided by one or more embodiments of the present invention will be better understood from the following detailed description and accompanying drawings, these drawings are for illustrative purposes only and are not intended to define any limitations of the present invention.

[0033] 1. Method for producing recycled resin compositions (1.1) Raw materials and additives (PCR material) The raw material for the recycled resin composition according to the present invention is PCR material. As mentioned above, "PCR (Post-Consumer Recycling) material" refers to used resin-containing recycled material.

[0034] There are no particular restrictions on the resin contained in the PCR material, and any resin commonly found in recycled materials may be used. Examples of such resins include acrylonitrile-butadiene-styrene copolymer (ABS resin) and polycarbonate (PC). Other examples include polyethylene (PE), polypropylene (PP), polystyrene (PS), acrylonitrile styrene resin (AS resin), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT).

[0035] PCR materials may be used individually or in combination of multiple types. For example, while ABS resin has moderate impact strength compared to PC, which has high impact strength, it is often sufficient to ensure everyday impact strength, and ABS resin is not expensive, so it is often included in PCR materials. Also, because PC has low fluidity, PCR materials containing both PC and ABS resin as a resin alloy may be used to compensate for this.

[0036] From the viewpoint of reducing carbon emissions, a higher proportion of PCR material in a recycled resin composition is preferable.

[0037] [Impact strength of PCR material] The "impact strength of the PCR material" according to the present invention includes not only the impact strength of the pulverized PCR material, but also the impact strength of the shredded material obtained by processing the pulverized PCR material into strands and then shredding them. Furthermore, if the PCR material according to the present invention has an appropriate particle size before pulverization, the "impact strength of the PCR material" according to the present invention shall include the impact strength of the PCR material before pulverization.

[0038] In this invention, the "impact strength of the PCR material" is, more precisely, the average impact strength measured when a sampled section of the PCR material is molded during pulverization or shredding. This impact strength is obtained from measuring molded pieces that conform to the specifications.

[0039] (Additives) The recycled resin composition according to the present invention may contain additives such as colorants, lubricants, compatibilizers, antioxidants, drip inhibitors, impact modifiers, and ultraviolet absorbers, in addition to the PCR material used as the raw material. Furthermore, as the impact modifier, in addition to additives based on particulate rubber, for example, virgin ABS may be used, thereby improving the impact strength of the recycled resin composition. In addition, one type of additive may be used alone, or two or more types may be used in combination.

[0040] Examples of colorants include inorganic and organic pigments. Examples of lubricants include metal salts of higher fatty acids and higher fatty acid amides. Examples of compatibilizers include random copolymer, graft copolymer, and block polymer compatibilizers. Examples of antioxidants include hindered phenol, sulfur-containing organic compound, and phosphorus-containing organic compound antioxidants. Examples of UV absorbers include benzotriazole, benzophenone, and salicylate UV absorbers.

[0041] From the viewpoint of exerting the effects of adding the additive, the additive content is preferably 0.3% by mass or more, and more preferably 0.5% by mass or more. Furthermore, from the viewpoint of not affecting melt mixing or properties that should not be altered, the additive content is preferably 20% by mass or less, and more preferably 15% by mass or less.

[0042] (1.2) Particle size control process (The grinding process) The PCR material, which is the raw material, is flaked for sorting and washing, and during this process, it is pulverized until it can pass through a screen mesh to achieve a certain particle size. It has been found that the lower the impact strength of the PCR material, the more likely it is to generate fragments and fine powder significantly smaller than the screen mesh size. Since the presence of fine powder makes the product unsuitable, it is removed as material adhering to the inside of the pelletizer or as material that passes through the mesh, which is too small for the pellets to pass through. Hereafter, "pulverized flaked PCR material" will also be simply referred to as "flakes." Also, "flaked pulverized material" will also be referred to as "flaked pulverized material."

[0043] Therefore, if the correlation between the particle size and recovery rate of the flakes in the PCR material and the impact strength when they are molded is obtained in advance, the impact strength of the flakes whose particle size and recovery rate are measured afterward can be estimated without molding. "Particle size of the pulverized material" refers to the number of particles, volume, and mass of the pulverized material, and is a concept that includes their distribution.

[0044] Furthermore, by using the estimated impact strength of the PCR material, it becomes possible to determine the appropriate amount of impact-resistant modifier to achieve an appropriate impact strength for the recycled resin composition.

[0045] (Process of processing into strands and then shredding) The PCR material, which is the raw material, is generally first crushed to a size suitable for melt-mixing, and then fed into a single-screw or twin-screw mixer to be melt-mixed and processed into strands. The PCR material processed into strands is then shredded into pellets using a pelletizer.

[0046] Fine powder is generated during shredding in a pelletizer, and it was found that the lower the impact strength of the PCR material, the more likely fine powder is to be generated. Since the presence of fine powder makes the product unsuitable, it is removed as residue adhering to the inside of the pelletizer or as material that passes through a mesh too small to allow the pellets to pass through. Hereafter, "shredded PCR material that has been pelletized and from which fine powder has been removed" will also be simply referred to as "pellets." Also, "shredded material that has been pelletized" will also be referred to as "shredded material in pellet form."

[0047] Therefore, if the correlation between the pellet recovery rate in the PCR material and the impact strength when it is molded is obtained in advance, it becomes possible to estimate the impact strength of the pellets whose recovery rate is measured afterward without molding them.

[0048] Furthermore, by using the estimated impact strength of the PCR material, it becomes possible to determine the appropriate amount of impact-resistant modifier to achieve an appropriate impact strength for the recycled resin composition.

[0049] (1.3) Process for calculating the excess of crushing or shredding "Excessive crushing or shredding" refers to excess in terms of particle size and recovery rate of crushed material, or recovery rate of shredded material.

[0050] (Value calculated from granularity) In the particle size control process according to the present invention, "particle size" refers to the "particle size of the crushed material." Various values ​​can be calculated from the particle size of the crushed material. Several variations of the values ​​calculated from this particle size are described below.

[0051] Variations include, for example, the total mass of the sampled PCR material, the number of selected flake-like particles from the PCR material, and the average mass of the flake-like particles, which can be determined from these values.

[0052] Other examples include the total mass when a certain number of particles (e.g., 100 particles) are extracted from the aforementioned flake-like crushed material, and the average mass per flake.

[0053] Furthermore, the number of particles obtained when a certain mass (e.g., 20g) of the above-mentioned flake-like pulverized material is measured and extracted can also be cited.

[0054] Furthermore, if the above-mentioned flake-like pulverized material is sorted by a pulverizing screen, the pass-through rate of the pulverized material can be calculated by passing it through a screen with a smaller mesh size (e.g., half the size) than the aforementioned pulverizing screen.

[0055] (Recovery rate) The recovery rate of crushed or shredded material can be calculated using the following formula. In the following formula, "sorting" means "removing fine particles by sieving or similar methods." Formula) Recovery rate of pulverized material [%] = Mass of pulverized material after sorting / Mass of PCR material before pulverization Formula) Recovery rate of shredded material [%] = Mass of shredded material after sorting / Mass of PCR material before shredding or before mixing (which is directly related to shredding)

[0056] (1.4) Process for estimating impact strength The impact strength of the PCR material is estimated based on correlation information between the excess crushing or shredding of the PCR material and the impact strength of the PCR material, which is prepared in advance.

[0057] The values ​​related to the excess grinding or shredding of the PCR material measured for the purpose of creating correlation information in advance are values ​​related to the particle size and recovery rate of the ground material. There are no particular restrictions on the values ​​that indicate the excess grinding or shredding of the PCR material, but they may be values ​​related to mass, size, etc.

[0058] (Methods for measuring and calculating impact strength) The impact strength to be measured for the correlation information to be created in advance can be calculated by preparing notched Charpy impact test specimens in accordance with JIS-K7111-1 (ISO179-1) and performing notched Charpy impact tests on each specimen.

[0059] (Example of correlation information) There are no particular restrictions on the correlation information between the excessive grinding or shredding of the PCR material and the impact strength of the PCR material. For example, a graph showing the relationship between the mass of the pulverized PCR material and the impact strength may be used as correlation information.

[0060] It is preferable to calculate the correlation coefficient in the graph at this time.

[0061] By calculating the correlation coefficient, the strength of the correlation between the mass of the crushed or shredded PCR material and its impact strength can be determined. If the mass of the crushed PCR material and its impact strength show a strong positive correlation, it becomes easy to estimate the impact strength of the PCR material based on the graph.

[0062] (1.5) Process for adjusting impact strength The impact strength of the recycled resin composition according to the present invention is adjusted based on the correlation information described above, which is prepared in advance.

[0063] For example, if the impact strength of the PCR material estimated by the above correlation information is low, the impact strength is adjusted by applying a process that improves the impact strength.

[0064] There are no particular restrictions on the method for adjusting the impact strength of the recycled resin composition, but for example, if the estimated impact strength of the PCR material is low, it is preferable to add an additive such as an impact-resistant modifier to the pulverized or shredded material of the PCR material.

[0065] While commonly known additives can be used, thermoplastic elastomers mainly composed of olefin-derived structural units, such as ethylene propylene diene rubber (EPDM), are preferred.

[0066] Commonly known thermoplastic elastomers include, for example, acrylonitrile-butadiene-styrene copolymer (ABS), methyl methacrylate-butadiene-styrene copolymer (MBS), and styrene-butadiene-styrene copolymer (SBS). Other examples include styrene-ethylene-butylene-styrene block copolymer (SEBS), ethylene-octene copolymer (EOR), and butyl acrylate-methyl methacrylate copolymer.

[0067] Virgin ABS is preferred, and core-shell type particulate additives with an elastomer core are more preferred. This allows for the production of a recycled resin composition that is stable and has excellent impact strength. These may be used individually or in combination of two or more.

[0068] Examples of core-shell type elastomers include a core layer containing a polyorganosiloxane-based rubber component and an acrylic-based rubber component, i.e., a rubber layer containing an aromatic vinyl polymer.

[0069] Polyorganosiloxane-based rubber components are produced by polymerizing organosiloxane monomers. As the organosiloxane, cyclic organosiloxanes with three or more membered rings are used, and those with three to six membered rings are preferably used.

[0070] Examples of such organosiloxanes include hexamethyltricyclosiloxane, octamethylcyclosiloxane, decamethylpentacyclosiloxane, dodecamethylhexacyclosiloxane, trimethyltriphenylsiloxane, tetramethylphenylcyclotetrasiloxane, and octaphenylcyclotetrasiloxane.

[0071] As for the acrylic rubber component, it is preferable to obtain one obtained by polymerizing an alkyl (meth)acrylate ester such as butyl acrylate with a small amount of a crosslinkable monomer such as butylene diacrylate.

[0072] Examples of (meth)acrylic acid esters mentioned above include, in addition to butyl acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, and esters of methacrylic acid such as methyl, ethyl, propyl, butyl, octyl, 2-ethylhexyl, lauryl, and stearyl.

[0073] Examples of crosslinkable monomers include, in addition to butylene diacrylate, vinyl compounds such as butylene dimethacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, butylene glycol diacrylate, butylene glycol dimethacrylate, oligoethylene glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, and trimethylolpropane trimethacrylate, as well as allyl compounds such as allyl acrylate, allyl methacrylate, diallyl malate, diallyl fumarate, diallyl uitanylate, monoallyl malate, monoallyl fumarate, and triallyl cyanurate.

[0074] The above rubber components may also contain conjugated diene compounds, such as butadiene, isoprene, pentadiene, and 2,3-dimethylbutadiene.

[0075] The core layer may be a mixture of the polyorganosiloxane-based rubber component and the acrylic-based rubber component, or a composite rubber obtained by copolymerizing and / or graft polymerizing these can be used. It is also preferable that the composite rubber is a silicone-acrylic composite rubber, in which the polyorganosiloxane-based rubber component and the acrylic-based rubber component are integrated by chemical bonding such as copolymerization and / or graft polymerization.

[0076] The shell layer of a core-shell type elastomer must contain at least an aromatic vinyl polymer. Examples of aromatic vinyl compounds include styrene, α-methylstyrene, methylstyrene, vinylxylene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, fluorostyrene, p-tert-butylstyrene, ethylstyrene, and vinylnaphthalene. Among these, styrene is preferred because it is inexpensive and easy to handle during polymerization.

[0077] Aromatic vinyl polymers may be homopolymers or copolymers. Preferably, the copolymer is obtained by copolymerizing at least one monomer selected from vinyl cyanide monomers, methacrylic acid ester monomers, and acrylic acid ester monomers.

[0078] Examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile.

[0079] Examples of preferred methacrylate monomers include ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, and tertiary butyl methacrylate.

[0080] Examples of preferred acrylic acid ester monomers include methyl acrylate, ethyl acrylate, and butyl acrylate.

[0081] Furthermore, aromatic vinyl polymers can copolymerize with other copolymerizable monomers besides those mentioned above. For example, glycidyl group-containing vinyl monomers can also be copolymerized, and examples of such monomers include glycidyl methacrylate, glycidyl acrylate, vinyl glycidyl ether, allyl glycidyl ether, glycidyl ether of hydroxyalkyl (meth)acrylate, glycidyl ether of polyalkylene glycol (meth)acrylate, and glycidyl itaconate.

[0082] As the shell layer of the core-shell type elastomer, among the above, a copolymer obtained by copolymerizing a styrene monomer with a vinyl cyanide monomer is preferred, and a styrene-acrylonitrile copolymer is particularly preferred.

[0083] In core-shell type elastomers, the core layer and shell layer are usually preferably bonded together by graft bonding. This graft copolymerization is achieved, if necessary, by adding a graft cross-agent that reacts with the shell layer during polymerization of the rubber layer, thereby providing reactive groups to the rubber layer, and then forming the shell layer.

[0084] The graft cross-linking agent is a compound having a vinyl bond, and in the case of acrylic rubber components, it can also be used as the cross-linking monomer mentioned above.

[0085] Polyorganosiloxane-based rubber components use organosiloxanes having vinyl bonds or organosiloxanes having thiols, and preferably (meth)acryloyloxyalkylsiloxanes and vinylsiloxanes, which are organosiloxanes having vinyl bonds.

[0086] Among (meth)acryloyloxyalkylsiloxanes, methacryloyloxyalkylsiloxanes are preferred, and specific examples include β-methacryloyloxyethyl dimethoxymethylsilane, γ-methacryloyloxypropyl methoxydimethylsilane, γ-methacryloyloxypropyl dimethoxymethylsilane, γ-methacryloyloxypropyl trimethoxysilane, γ-methacryloyloxypropyl ethoxydiethoxysilane, γ-methacryloyloxypropyl diethoxymethylsilane, and δ-methacryloyloxybutyl diethoxymethylsilane.

[0087] Examples of vinylsiloxanes include vinylmethyldimethoxysilane and vinyltrimethoxysilane. Examples of mercaptosiloxanes, which are organosiloxanes containing thiols, include γ-mercaptopropyldimethoxymethylsilane, γ-mercaptopropyltrimethoxysilane, and γ-mercaptopropyldiethoxyethylsilane.

[0088] The amounts of impact modifier and virgin ABS are preferably determined based on the estimated impact strength calculation results mentioned above, thereby producing a recycled resin composition with stable and excellent impact strength.

[0089] 2. Resin molded products and electronic equipment The resin molded product according to the present invention is molded using a recycled resin composition and can be used as an exterior or interior component of electronic equipment. Electronic equipment is equipment that includes electronic circuits.

[0090] Such electronic devices include, for example, scanners that read original document images, and photocopiers that print the scanned original images. Other electronic devices include printers and facsimile machines that print image data input from external sources, or multifunction devices that combine these functions. Printers may be, for example, electrophotographic (EP) or inkjet printers.

[0091] Such electronic devices include exterior and interior components as resin molded products formed using the aforementioned recycled resin composition. These exterior and interior components constitute, for example, the housing, and include the exterior housing or a part thereof, as well as the interior housing or a part thereof for housing individual components and materials arranged inside the exterior housing.

[0092] The resin molded products are manufactured by injection molding using recycled resin compositions. [Examples]

[0093] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, the units "parts" or "%" are used, and unless otherwise specified, they represent "parts by mass" or "mass%".

[0094] A. Recycled resin compositions relating to crushed materials (A.1) Creation of prior correlation information regarding crushed material for the purpose of estimating impact strength (Preparation of raw materials) Six lots of recycled ABS resin parts from pachinko machines were collected and designated as PCR materials [1] to [6], and used as raw materials. The mass of PCR materials [1] to [6] was measured before crushing the raw materials.

[0095] (Crush) PCR materials [1] to [6] were coarsely ground using a high-speed uniaxial mill for hard plastics equipped with a general-purpose metal screen mesh to produce coarsely ground flakes. A Φ20 mm screen mesh was used as the metal screen mesh. The coarsely ground flakes of each PCR material produced in this way were designated as coarsely ground flakes [1] to [6]. 5 to 25 g of each coarsely ground flake were sampled, and their mass and number were measured, and the average mass per flake of each coarsely ground flake was calculated.

[0096] Subsequently, each of the selected coarsely ground flakes was weighed and then re-ground in a smaller grinder than the high-speed single-shaft grinder for hard plastics mentioned above to produce re-ground flakes. A Φ4mm metal screen mesh was used for the re-ground process. Furthermore, the flakes were sieved through a 1.7mm mesh to remove fine particles. Most of the fine particles generated at this stage were removed by adhering to the inner wall of the grinder, but further fine particles were removed by sieving through a 1.7mm mesh.

[0097] The re-ground flakes of each PCR material prepared in this manner were designated as re-ground flakes [1] to [6]. The mass of each re-ground flake was then measured.

[0098] (Recovery rate) The recovery rate was calculated based on the following formula. Formula) Recovery rate [%] = Mass of re-ground flakes / Mass of coarsely ground flakes before re-ground

[0099] (Impact strength) Each re-pulverized flake was fed into a molding machine to prepare notched Charpy impact test specimens in accordance with JIS-K7111-1 (ISO 179-1). The test specimens of the recycled resin compositions made from each PCR material prepared in this manner were designated as test specimens [1] to [6]. The impact strength was calculated by performing a notched Charpy impact test on each test specimen.

[0100] Table I below shows the average mass per grain of each coarsely ground flake made from PCR materials [1] to [6], the recovery rate of each re-ground flake, and the impact strength of test specimens formed from each re-ground flake.

[0101] [Table 1]

[0102] (Creation of prior correlation information) [Correlation coefficient between the average weight per coarsely ground flake particle and impact strength] Figure 1 is a graph showing the relationship between the average mass per grain of coarsely ground flake and impact strength, based on the values ​​listed in Table I, where the raw material is PCR material [1] to [6]. In Figure 1, "P4" represents the impact strength value relative to the average weight per grain of coarsely ground flake when the raw material is PCR material [4]. 2 This is the correlation coefficient.

[0103] The correlation coefficient between the average mass per particle of coarsely ground flakes using PCR materials [1] to [6] as raw materials and the impact strength was calculated and found to be 0.9998, indicating a very strong positive correlation.

[0104] Figure 2 is a graph showing the relationship between the average mass per coarsely ground flake and impact strength, excluding those in Figure 1 where the raw material located far away is the PCR material [4], based on the values ​​listed in Table I. Note that in Figure 2, "R 2 This is the correlation coefficient.

[0105] The correlation coefficient between the average mass per coarsely ground flake and the impact strength, using PCR materials [1] to [3], [5], and [6] as raw materials, was calculated to be 0.9796, indicating a very strong positive correlation.

[0106] [Correlation coefficient between the recovery rate of re-ground flakes and impact strength] Figure 3 is a graph showing the relationship between the re-pulverized flake recovery rate and impact strength when the raw material is PCR material [1] to [6], based on the values ​​listed in Table I. Note that in Figure 3, "R 2 This is the correlation coefficient.

[0107] The correlation coefficient between the recovery rate of re-pulverized flakes and impact strength, using PCR materials [1] to [6] as raw materials, was calculated to be 0.8449, indicating a strong positive correlation.

[0108] [Confirmation of impact intensity estimation using correlation information] From the above, it was confirmed that it is possible to estimate the impact strength of the sampled PCR material using the correlation information described above. Furthermore, this makes it possible to estimate the impact strength of the recycled resin composition manufactured using the said PCR material as a raw material.

[0109] (A.2) Adjustment of impact strength of crushed material Excluding the one using PCR material [4] as the raw material, the impact-resistant modifier [a] was added to each of the re-pulverized flakes [1] to [3], [5], and [6] according to the above estimation of impact strength, and the strands prepared by melt-kneading were shredded to produce additive-containing pellets. The additive-containing pellets produced in this way were designated as additive-containing pellets [1a] to [3a], [5a], and [6a].

[0110] As the impact-resistant modifier [a] mentioned above, 5% by mass of "Metablen SX-006" (silicone / acrylic rubber) manufactured by Mitsubishi Chemical Corporation was added to 95% by mass of re-pulverized flakes.

[0111] Furthermore, for those using PCR material [4] as the raw material, the Charpy impact strength was 12 kJ / m 2 For the reasons stated above, it was confirmed that the recycled resin composition had sufficient impact strength, and therefore, no adjustment of impact strength was made by adding an impact-resistant modifier.

[0112] Each additive-containing flake was fed into a molding machine to produce notched Charpy impact test specimens in accordance with the specifications. The test specimens of the recycled resin compositions made from each PCR material produced in this way were designated as additive-containing test specimens [1A] to [3A], [5A], and [6A]. The impact strength of each additive-containing test specimen was calculated by performing notched Charpy impact tests, and the results shown in Table II were obtained.

[0113] From the results in Table II, the recycled resin compositions using PCR materials [1] to [3], [5], and [6] as raw materials achieved a Charpy impact strength of 12 kJ / m² upon addition of an impact modifier. 2It was confirmed that the above constitutes a recycled resin composition.

[0114] [Table 2]

[0115] From the above, it was confirmed that it is possible to produce a recycled resin composition with sufficient impact strength by crushing and shredding the PCR materials [1] to [6], which are the raw materials, and adding an appropriate impact-resistant modifier based on the estimated impact strength and kneading it.

[0116] B. Recycled resin compositions for shredded material (B.1) Creation of prior correlation information regarding shredded material for the purpose of estimating impact strength (Preparation of raw materials) Four types of PCR materials containing ABS resin with different materials were collected. These four types of PCR materials will be referred to as PCR materials [7] to

[10] . PCR material [7] is derived from home appliances manufactured by Company A, and PCR material [8] is derived from small home appliances manufactured by the same company. PCR material [9] is derived from home appliances manufactured by Company B, and PCR material

[10] is derived from pachinko machines manufactured by Company C.

[0117] (Shredded) PCR material [7], PCR material [8], PCR material [9], and PCR material

[10] were pulverized and fed into a twin-screw compounder. The resulting strands were shredded in a pelletizer to produce four types of pellets. Most of the fine powder generated at this time was removed by adhering to the inner wall of the pelletizer, but further fine powder was removed by sieving with a mesh size of 1.7 mm.

[0118] The pellets made from the PCR material [7], PCR material [8], PCR material [9], and PCR material

[10] prepared in this manner were designated as pellets [7] to

[10] .

[0119] (Recovery rate) The recovery rate was calculated based on the following formula. Formula) Recovery rate [%] = Mass of pellets / Mass of strands

[0120] (Impact strength) Each pellet was fed into a molding machine to produce notched Charpy impact test specimens in accordance with the specifications. The pellet test specimens of the recycled resin compositions made from each PCR material produced in this manner were designated as pellet test specimens [7] to

[10] . The impact strength of each pellet test specimen was calculated by performing notched Charpy impact tests, and the results shown in Table III were obtained.

[0121] Table III below shows the recovery rate of each pellet made from PCR materials [7] to

[10] , and the impact strength of each pellet.

[0122] (Creation of prior correlation information) [Correlation coefficient between pellet recovery rate and impact strength] Figure 4 is a graph showing the relationship between pellet recovery rate and impact strength when the raw material is PCR material [7] to

[10] , based on the values ​​listed in Table III. Note that in Figure 4, "R 2 This is the correlation coefficient.

[0123] The correlation coefficient between the pellet recovery rate and impact strength, using PCR materials [7] to

[10] as raw materials, was calculated to be 0.8704, indicating a strong positive correlation.

[0124] [Confirmation of impact intensity estimation using correlation information] From the above, it was confirmed that it is possible to estimate the impact strength of the sampled PCR material using the correlation information described above.

[0125] The recycled resin compositions [7] to

[10] were evaluated using the following evaluation criteria. Pass: The Charpy impact strength of the test specimen is 9 kJ / m². 2 That's all. Failure: The Charpy impact strength of the test specimen was 9 kJ / m². 2 It is less than.

[0126]

Table 3

[0127] (B.2) Adjustment of impact strength for shredded materials In addition, a strong positive correlation is observed in the correlation coefficients calculated for the pellet recovery rate and the impact strength with the raw materials being PCR materials [7] to

[10] . From this, it can be seen that in the recycled resin compositions using PCR materials [7] and [9] in Table III as raw materials, if the impact strength is adjusted by adding an impact modifier based on the correlation coefficient as described above, it is possible to produce a recycled resin composition that meets the acceptance criteria. Alternatively, it is also possible to carry out production countermeasures such as not using defective products, diverting them to applications where low strength is acceptable, or mixing them with high-strength products for use.

[0128] As described above, the embodiments of the present invention have been described and illustrated in detail. However, the disclosed embodiments are created only for the purpose of illustration and exemplification and are not restrictive. The scope of the present invention should be interpreted by the terms of the appended claims.

Explanation of reference signs

[0129] R 2 Correlation coefficient Value of impact strength with respect to the average weight per single coarse crushed flake where the P4 raw material is PCR material [4]

Claims

1. A method for producing a recycled resin composition, The aforementioned recycled resin composition uses PCR material as a raw material. The PCR material is ground to control the particle size, A step of calculating the excess amount of crushing of the PCR material, or a step of shredding the PCR material and calculating the excess amount of shredding of the PCR material, A step of estimating the impact strength of the PCR material from the degree of excessive crushing or shredding of the PCR material, The process includes adjusting the impact strength of the recycled resin composition based on the estimated impact strength of the PCR material, The impact strength of the recycled resin composition is adjusted based on correlation information between the excess crushing or shredding of the PCR material prepared in advance and the impact strength of the PCR material. A method for producing a recycled resin composition characterized by the above.

2. The excess of the crushing or shredding of the PCR material is calculated based on at least one of the following: the particle size of the crushed PCR material and the recovery rate of the crushed or shredded PCR material. A method for producing the recycled resin composition described in claim 1.

3. The pulverized PCR material is in the form of flakes. A method for producing the recycled resin composition described in claim 1.

4. The fragments of the PCR material are in the form of pellets. A method for producing the recycled resin composition described in claim 1.

5. In the step of adjusting the impact strength of the recycled resin composition, at least an impact-resistant modifier is added as an additive. The impact strength of the recycled resin composition is adjusted by the amount of the impact-resistant modifier. A method for producing a recycled resin composition according to any one of claims 1 to 4.

6. The PCR material contains ABS resin, In the step of adjusting the impact strength of the recycled resin composition, at least one of an impact modifier other than the virgin ABS resin composition and the virgin ABS resin composition is added as an additive. A method for producing the recycled resin composition according to claim 5.

7. A resin molded article in which a recycled resin composition manufactured by the manufacturing method described in claim 5 is molded.

8. Includes the resin molded article described in claim 7 A resin housing characterized by the following features.

9. The resin housing is provided according to claim 8. An electronic device characterized by the following features.

Images