JP6718636B1 - Method for producing waste resin molded product containing inorganic substance powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method by which a good resin waste material molding can be obtained by utilizing a resin waste material highly filled with an inorganic substance powder. According to the present invention, in a method for producing a resin waste material molded body containing a thermoplastic resin and an inorganic substance powder from a resin waste material mixed with an inorganic substance powder, the resin waste material mixed with an inorganic substance powder is selected according to the particle diameter of the inorganic substance powder. The present invention provides a method for producing a resin waste material molded body, which comprises: a sorting step for crushing, a crushing step for crushing a selected resin waste material containing an inorganic substance powder, and a kneading step for kneading with an extruder. In the selection step, it is preferable to measure the particle size of the inorganic substance powder by the X-ray small angle scattering method. [Selection diagram] None

Description

The present invention relates to a method for manufacturing a resin waste material molded body. More specifically, the present invention relates to a material recycling method for waste resin material containing inorganic substance powder.

In recent years, in consideration of environmental problems and the like, there is an increasing interest in recycling resources such as resin waste materials. The treatment of various types of resin waste materials in general waste and industrial waste has become a social problem, and recycling methods such as fuel substitution and oil conversion have been studied. Among them, material recycling is desired to establish technical aspects because it can fundamentally solve environmental problems by using waste materials as raw materials. In particular, so-called up-cycle technology has been attracting attention, in which waste materials are not simply reused but are processed so as to enhance their value as products.

However, in the recycling of resin waste materials, there is a problem that the mechanical strength of the obtained molded product becomes low due to the heat history and mechanical load during the melt molding. In particular, waste materials collected from the market are often deteriorated by oxygen, heat, light or the like and mixed with impurities while being used as products. Therefore, it is not rare that only recycled products whose physical properties are significantly deteriorated and which cannot be said to be up-cycled can be obtained. The wide variety of waste resin materials also makes material recycling difficult. When attempting to recycle using a plurality of waste materials of unknown resin type, the appearance and physical properties of the obtained resin waste material molded body may be deteriorated due to the difference in the resin in each waste material. Moldability may be reduced, and in extreme cases, molding itself becomes impossible.

Therefore, at the time of material recycling, a technique of measuring the specific gravity or the like of the resin waste material or analyzing the polymer component in the waste material to select the waste material and then remolding the material is being studied. For example, in Patent Documents 1 to 3, methods for analyzing waste materials by using a spectroscopic analysis method such as infrared spectroscopy, fluorescent X-ray analysis, and NMR have been proposed and put into practical use.

As a technique to tackle environmental problems from a viewpoint different from the above recycling, an inorganic substance powder-blended thermoplastic resin composition obtained by highly filling an inorganic substance powder in a thermoplastic resin has been proposed and put into practical use. (See, for example, Patent Document 4). As the inorganic substance powder, in particular, calcium carbonate is a resource that is abundant in nature and can preferably meet the demand from the viewpoint of environmental protection. Also for such a thermoplastic resin composition containing an inorganic substance powder, the recycling of resources as described above is an issue to be examined. For example, Patent Document 5 has a step of molding a raw material plastic containing a filler-containing plastic into a sheet by kneading and extrusion, and a bending treatment step of treating the molded sheet by generating stress acting inside the molded sheet. A method of making a recycled filler-containing plastic sheet is disclosed. In a preferred embodiment of the invention described in Patent Document 5, the waste plastic contains 40 to 85% by mass of the filler with respect to the total mass, and shear stress occurs in the flow direction of the molded sheet, so that the internal structure of the sheet relaxes. It is estimated that sufficient strength and elongation at break can be obtained. In Patent Document 6, a recycled polymer containing a filler in an amount of about 10 to 15% by mass is used for injection molding, a filler such as calcium carbonate is added in an amount of about 10 to 15% by mass, and a filler-containing polymer is used. A technique for defining the melt flow value and the like within a specific range is disclosed.

JP, 2003-11124, A JP, 2004-122575, A JP, 2016-49736, A JP, 2013-10931, A JP, 2015-212029, A Japanese Patent Publication No. 2018-519410

As described above, in material recycling of resin waste materials, it is important to analyze polymer components in the waste materials and select the waste materials before molding. Therefore, conventionally, the techniques described in Patent Documents 1 to 3 have been developed and put into practical use.

However, it has become clear that these techniques are not necessarily effective in recycling a resin waste material highly filled with an inorganic substance powder. Heretofore, it has been rare to recover the resin highly filled with the inorganic substance powder, so that the material recycling will not be hindered as long as the above analysis and selection are performed. In fact, even in the above Patent Documents 5 and 6 regarding recycling of the polymer filled with the inorganic substance powder, although the average particle diameter of the inorganic substance powder and the like are referred to, the analysis method and the selection of the waste material by the particle diameter are described. Absent.

The inventors of the present invention are actively working to recycle waste materials highly filled with an inorganic substance powder, and in the process, it became clear that the characteristics of the inorganic substance powder also greatly influence the material recycling of such waste materials. For example, when recycling a waste resin material containing a large amount of inorganic substance powder such as calcium carbonate, simply selecting the type of resin causes a large variation in the particle size of the included inorganic substance powder. It is difficult to obtain uniform mechanical properties and good surface condition when a molded product is manufactured by using the above method. In particular, when it is desired to form a thin molded product such as a film, it becomes extremely difficult to perform good molding.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a manufacturing method using a resin waste material, which can obtain a resin waste material molded body having excellent physical properties and appearance. In particular, the present invention can obtain a resin waste material molded body having a uniform particle size of the inorganic material powder even when producing a resin waste material molded body from a resin waste material highly filled with an inorganic substance powder, and it is possible to obtain variations in physical properties and appearance. An object of the present invention is to provide a manufacturing method capable of obtaining a suppressed resin waste material molded article of good quality.

The present inventors further studied the production of a resin molded product by material recycling of waste materials highly filled with an inorganic substance powder, and in particular, a good product cannot be obtained unless the particle size distribution of the inorganic substance powder is controlled; a resin having good physical properties It has been found that it is important to select a resin waste material and to use a resin waste material containing an inorganic material powder having a particle diameter according to the purpose in manufacturing a molded product from a waste material highly filled with an inorganic material powder. Based on this knowledge, by providing a step of sorting resin waste materials according to the particle size of the inorganic substance powder, it is possible to stabilize the resin molded articles with uniform mechanical properties and good surface condition as resin molded articles using the resin waste materials. As a result, the present invention has been completed, and the present invention has been completed. Specifically, the present invention provides the following.

(1) In a method for producing a resin waste material molded body containing a thermoplastic resin and an inorganic substance powder from a resin waste material containing an inorganic substance powder, a selection step of selecting the resin waste material containing an inorganic substance powder according to the particle diameter of the inorganic substance powder, A method for producing a resin waste material molding, comprising a crushing step of crushing the selected inorganic material powder-blended resin waste material and a kneading step of kneading with an extruder.

(2) The method for producing a resin waste material molding according to (1), wherein in the selecting step, the particle size of the inorganic substance powder is measured by the X-ray small angle scattering method.

(3) The method for producing a resin waste material molding according to (1) or (2), wherein the thermoplastic resin contains a polyolefin resin.

(4) The method for producing a resin waste material molding according to any of (1) to (3), wherein the thermoplastic resin contains a polypropylene resin.

(5) The method for producing a resin waste material molding according to any one of (1) to (4), wherein the inorganic substance powder contains calcium carbonate.

(6) The resin waste material molded body according to any one of (1) to (5), wherein the resin waste material molded body contains a thermoplastic resin and an inorganic substance powder in a mass ratio of 50:50 to 10:90. Production method.

(7) The method for producing a resin waste material molding according to (5), wherein the calcium carbonate has an average particle diameter of 0.5 μm or more and 13.5 μm or less as measured by an air permeation method.

(8) The method for producing a resin waste material molding according to any one of (1) to (7), wherein the kneading step includes a kneading step using a twin-screw kneading extruder.

(9) The selection step is one or more selected from mid-infrared spectroscopic analysis, near-infrared spectroscopic analysis, infrared spectroscopic analysis, Raman spectroscopic analysis, fluorescent X-ray analysis, and X-ray diffraction analysis. The method for producing a resin waste material molded body according to any one of (1) to (8), further comprising selecting a type of resin and/or inorganic substance powder by an analysis method.

(10) The method for producing a resin waste material compact according to any one of (1) to (9), wherein the resin waste material compact is a resin pellet.

(11) The method for producing a resin waste material molded body according to any one of (1) to (9), wherein the resin waste material molded body is an inflation sheet or an inflation film.

According to the present invention, there is provided a method for producing a molded article that is excellent in physical properties and appearance using a resin waste material. In the manufacturing method of the present invention, a desired molded product can be manufactured without sacrificing physical properties and moldability, even from a recycled material containing a thermoplastic resin highly filled with an inorganic substance powder. In particular, even in the production of thin-walled molded products such as films, it is possible to obtain molded products having uniform mechanical properties and good surface conditions.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not particularly limited thereto.

<1. Manufacturing method of resin waste material molding>
A method for producing a resin waste material molded body according to the present invention (hereinafter, also simply referred to as “production method”) is a method for producing a thermoplastic resin and an inorganic material from a resin waste material containing an inorganic substance powder (hereinafter also simply referred to as “resin waste material”). It is a method for producing a resin molded body containing a substance powder. In addition, the resin molded product obtained by the manufacturing method using the inorganic material powder-blended resin waste material in this manner is referred to as a “resin waste material molded product”.

In this manufacturing method, the raw material is a waste material (recycled material), which is a resin waste material mixed with an inorganic substance powder. Inorganic substance powder-containing resin waste materials include various thermoplastic resins and various inorganic substance powders. Here, not only the type of the inorganic substance powder contained in the resin waste containing the inorganic substance powder but also the particle size of the inorganic substance powder contained therein varies, and it varies depending on the used resin waste containing the inorganic substance powder.

Specifically, the manufacturing method according to the present invention includes a sorting step of sorting the inorganic material powder-containing resin waste material according to the particle size of the inorganic substance powder, a pulverizing step of pulverizing the selected inorganic material powder-containing resin waste material, and an extruder. And a kneading step of kneading. In the selection step, the particle size of the inorganic substance powder is preferably measured by the X-ray small angle scattering method.

In a method for producing a resin waste material molded body using such an inorganic substance powder-containing resin waste material, according to the production method of the present invention, in the sorting step, the inorganic substance powder-containing resin waste material used as a raw material is Since the particles are sorted according to the particle diameter of, the raw material can be, for example, only the inorganic material powder-blended resin waste material containing the inorganic material powder in the desired particle diameter range. Thus, even when a resin waste material molded body is manufactured from an inorganic material powder-blended resin waste material, it is possible to obtain a resin waste material molded body having a uniform particle size of the inorganic material powder, which suppresses variations in physical properties and appearance. A resin waste material molding can be obtained.

<2. About waste resin moldings>
Prior to a detailed description of each step of the manufacturing method according to the present invention, the thermoplastic resin constituting the resin waste material molding to be manufactured and the inorganic substance powder will be described. As described above, the manufacturing method according to the present invention is a method for manufacturing a resin waste material molded body containing a thermoplastic resin and an inorganic material powder from an inorganic material powder-blended resin waste material, and thus is obtained by manufacturing. The thermoplastic resin forming the resin waste material molded body and the inorganic substance powder include at least a part of the resin waste material containing the inorganic substance powder as the raw material. In the production method according to the present invention, only the resin waste material containing the inorganic substance powder may be used, or the resin waste material and the unused raw material may be used in combination. It is also possible to use a plurality of resin waste materials.

[Thermoplastic resin]
The thermoplastic resin is not particularly limited, and various types can be used depending on the use and function of the resin waste material molded body, the recovery status of the resin waste material, and the like. For example, polyethylene resin, polypropylene resin, polymethyl-1-pentene, polyolefin resin such as ethylene-cyclic olefin copolymer; ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer Functional groups such as polymers, ethylene-methacrylic acid copolymer metal salts (ionomers), ethylene-acrylic acid alkyl ester copolymers, ethylene-methacrylic acid alkyl ester copolymers, maleic acid-modified polyethylene, and maleic acid-modified polypropylene Polyolefin resin containing; polyamide resin such as nylon-6, nylon-6,6, nylon-6,10, nylon-6,12; aroma such as polyethylene terephthalate and its copolymer, polyethylene naphthalate, polybutylene terephthalate Polyester resins, thermoplastic polyester resins such as aliphatic polyester resins such as polybutylene succinate and polylactic acid; polycarbonate resins such as aromatic polycarbonate and aliphatic polycarbonate; atactic polystyrene, syndiotactic polystyrene, acrylonitrile- Polystyrene resins such as styrene (AS) copolymer and acrylonitrile-butadiene-styrene (ABS) copolymer; polyvinyl chloride resins such as polyvinyl chloride and polyvinylidene chloride; polyphenylene sulfide; polyether sulfone, polyether ketone , And polyether resins such as polyether ether ketone. You may contain these individually by 1 type or in combination of 2 or more type.

In the present invention, various thermoplastic resins such as those described above can be used. However, due to the large amount of resin waste material used as the raw material, that is, the large amount used in the market, a thermoplastic resin containing a polyolefin resin is used. Is preferably used. Recycling of polyolefin resins, which are frequently used in the market, can greatly contribute to solving environmental problems. As described above, in the production method of the present invention, in addition to using only the resin waste material as a raw material, a raw material obtained by blending an unused resin or the like with the resin waste material may be used, but since the polyolefin resin raw material is generally low cost, When the raw materials used are blended, it is particularly advantageous in terms of economy. Incidentally, depending on the physical properties of the target resin waste material molded body, it is also possible to use a blend of a polyolefin-based resin waste material and another type of unused resin raw material, or a polyolefin-based resin waste material and another resin waste material, Considering compatibility between resins and economic efficiency, it is preferable to exclusively use a polyolefin resin. The polyolefin resin is also easy to mold and is suitable for use in the present invention in terms of performance.

Here, the polyolefin-based resin is a polyolefin-based resin containing an olefin component unit as a main component, and specifically, as described above, polypropylene-based resin or polyethylene-based resin, polymethyl-1-pentene, ethylene- Examples thereof include cyclic olefin copolymers and the like, as well as mixtures of two or more thereof. The above-mentioned "main component" means that the olefin component unit is contained in the polyolefin resin in an amount of 50% by mass or more, and the content thereof is preferably 75% by mass or more, more preferably 85% by mass. % Or more, more preferably 90% by mass or more. The method for producing the polyolefin resin used in the present invention is not particularly limited, and can be obtained by any of a method using a Ziegler-Natta catalyst, a metallocene catalyst, oxygen, a radical initiator such as peroxide, and the like. It may be one.

Examples of the polypropylene-based resin include a resin having a propylene component unit of 50% by mass or more, and examples thereof include a propylene homopolymer and a copolymer with another α-olefin copolymerizable with propylene. Other α-olefins copolymerizable with propylene include, for example, ethylene, 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3,4-dimethyl-1-butene. And α-olefins having 4 to 10 carbon atoms such as 1-heptene and 3-methyl-1-hexene. The propylene homopolymer includes any of isotactic, syndiotactic, atactic, hemiisotactic and linear or branched polypropylene having various degrees of stereoregularity. The copolymer may be a random copolymer or a block copolymer, and may be not only a binary copolymer but also a ternary copolymer. Specifically, for example, ethylene-propylene random copolymer, butene-1-propylene random copolymer, ethylene-butene-1-propylene random terpolymer, ethylene-propylene block copolymer, and the like can be exemplified. .. In addition, other olefins copolymerizable with propylene in the copolymer are 25% by mass or less, particularly 15% by mass or less, based on 100% by mass of the entire inorganic material powder-filled resin composition. It is preferably contained, and the lower limit can be set to 0.3% by mass, for example. Further, these polypropylene resins may be used alone or as a mixture of two or more kinds.

Examples of the polyethylene-based resin include resins having an ethylene component unit of 50% by mass or more, and examples thereof include high-density polyethylene (HDPE), low-density polyethylene (LDPE), medium-density polyethylene, and linear low-density polyethylene (LLDPE). ), ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, ethylene-propylene-butene 1 copolymer, ethylene-butene 1 copolymer, ethylene-hexene 1 copolymer, ethylene-4 methylpentene 1 copolymer Examples thereof include polymers, ethylene-octene 1 copolymers, and the like, and also a mixture of two or more thereof.

In addition, polyethylene having a density of 0.942 g/cm ³ or more is usually “high density polyethylene (HDPE)”, and polyethylene having a density of 0.930 g/cm ³ or more and less than 0.942 g/cm ³ is usually “medium”. "Density polyethylene", polyethylene having a density of 0.910 g/cm ³ or more and less than 0.930 g/cm ³ is usually "low density polyethylene (LDPE)", polyethylene having a density of less than 0.910 g/cm ³ is usually It is called "ultra low density polyethylene (ULDPE)". Further, "linear low density polyethylene (LLDPE)" is usually a density of less than 0.911 g / cm ³ or more 0.940 g / cm ^3, preferably 0.912 g / cm ³ or more 0.928 g / cm less than ³ Has a density of.

Among the polyolefin resins, polypropylene resins are preferable because they have a particularly good balance between mechanical strength and heat resistance.

[Inorganic substance powder]
The inorganic substance powder is not particularly limited, and examples thereof include carbonates such as calcium, magnesium, aluminum, titanium, iron and zinc, sulfates, silicates, phosphates, borates, oxides, or water of these. Examples include powders of Japanese products, specifically, calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide, silicic acid. Aluminum, magnesium silicate, calcium silicate, aluminum sulfate, magnesium sulfate, calcium sulfate, magnesium phosphate, barium sulfate, silica sand, carbon black, zeolite, molybdenum, diatomaceous earth, sericite, shirasu, calcium sulfite, sodium sulfate, titanic acid Examples thereof include potassium, bentonite, wollastonite, dolomite and graphite. These may be synthetic or derived from natural minerals, and these may be contained alone or in combination of two or more kinds.

Furthermore, the shape of the inorganic substance powder is not particularly limited, and may be any of particles, flakes, granules, fibers, and the like. Further, the particles may have a spherical shape generally obtained by a synthetic method, or may have an irregular shape obtained by crushing a collected natural mineral. ..

As the inorganic substance powder, calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide and the like are preferable, and calcium carbonate is particularly preferable. Further, as the calcium carbonate, either one prepared by a synthetic method, so-called light calcium carbonate, or so-called heavy calcium carbonate obtained by mechanically pulverizing and classifying a natural raw material mainly composed of CaCO ₃ , such as limestone, is used. Or a combination of these may be used.

Here, the heavy calcium carbonate is obtained by mechanically crushing and processing natural limestone or the like, and is clearly distinguished from synthetic calcium carbonate produced by a chemical precipitation reaction or the like. The pulverization method includes a dry method and a wet method, but the dry method is preferable.

The heavy calcium carbonate particles are, for example, different from the light calcium carbonate produced by the synthetic method, and are characterized by the irregularity of the surface and the size of the specific surface area due to the fact that the particles are formed by the pulverization process. Since the heavy calcium carbonate particles have such an irregular shape and a large specific surface area, the heavy calcium carbonate particles have a larger contact interface with the thermoplastic resin when compounded in the thermoplastic resin. It has an effect on uniform dispersion.

The specific surface area of the heavy calcium carbonate particles is not particularly limited, but is about 3,000 cm ² /g or more and 35,000 m ² /g or less, although it depends on the average particle diameter. desired. The specific surface area here is based on the air permeation method. When the specific surface area is within this range, deterioration of processability of the obtained molded article tends to be suppressed.

Further, the amorphousness of the heavy calcium carbonate particles can be represented by the low degree of spheroidization of the particle shape and is not particularly limited, but specifically, the roundness is 0.50. Or more and 0.95 or less, more preferably 0.55 or more and 0.93 or less, and still more preferably 0.60 or more and 0.90 or less. If the roundness of the heavy calcium carbonate particles is within the range, the strength and molding processability of the molded product will be appropriate. Here, the roundness can be represented by (projected area of particles)/(area of a circle having the same perimeter as the projected perimeter of particles). The method for measuring the roundness is not particularly limited, and for example, the projected area of the particles and the projected perimeter of the particles may be measured from a micrograph, and generally commercially available image analysis software may be used.

Further, the surface may be surface-modified according to a conventional method in order to enhance the dispersibility or reactivity of the inorganic substance powder. Examples of the surface modification method include a physical method such as plasma treatment and a method in which the surface is chemically surface-treated with a coupling agent or a surfactant. Examples of the coupling agent include silane coupling agents and titanium coupling agents. The surfactant may be anionic, cationic, nonionic or amphoteric, and examples thereof include higher fatty acids, higher fatty acid esters, higher fatty acid amides and higher fatty acid salts. On the contrary to these, the inorganic substance powder which is not surface-treated may be contained.

As described above, in the method for producing a resin waste material molding of the present invention, various known inorganic material powder-containing resin waste materials can be used, but the thermoplastic resin and the inorganic substance contained in the resin waste material molding to be produced The effect of the present invention becomes particularly remarkable when the mass ratio to the powder is 50:50 to 10:90. This is because, in the resin composite material highly filled with the inorganic substance powder, the influence of the inorganic substance powder on the physical properties of the molded article cannot be ignored, and it is particularly important to control the particle size. The effect of the present invention becomes more prominent in the resin waste material molded body in which the mass ratio of the thermoplastic resin and the inorganic substance powder is 40:60 to 20:80, particularly 40:60 to 25:75.

<3. About each step of the manufacturing method>
As described above, the manufacturing method according to the present invention includes a selection step of selecting the inorganic material powder-containing resin waste material according to the particle size of the inorganic material powder, a pulverizing step of crushing the inorganic material powder-containing resin waste material, and a kneading by an extruder. And a kneading step of In addition, the molding process may be provided in a subsequent stage, and the processes from selection to molding may be continuously performed.

<3-1. Sorting process>
In the selection step, the resin waste material containing the inorganic substance powder is selected according to the particle size of the inorganic substance powder.

The method for measuring the particle size is not particularly limited, and various known methods can be used. For example, a small amount of sample may be drawn from each lot of waste resin material, the resin may be removed by heating if necessary, and then the measurement may be performed by observing with an SEM, TEM, or an optical microscope, and the resin may be removed in the same manner. The particle size of the obtained inorganic substance powder can also be measured using a commercially available particle size distribution meter. It is also possible to measure the particle size by observing the cross section SEM of the resin waste material. However, in the present invention, it is preferable to measure the particle size of the inorganic substance powder by the X-ray small angle scattering method. The small-angle scattering method allows continuous selection work, and the particle size of the inorganic substance powder inside the sample can be measured without pretreatment such as heat removal of the resin, and there are errors due to sampling points as in microscope observation. Since it is less likely to occur, it is most suitable for use in the selection step in the present invention.

[X-ray small angle scattering method]
The X-ray small angle scattering method itself is known. X-ray small-angle scattering (also called small-angle X-ray scattering, abbreviated as SAXS) is a method for measuring scattered X-rays with a scattering angle of several degrees or less, generally 5° or less, and generally 1 to 1000 nm, and extremely small angle. Scattering at 10°C is effective for structural parameter analysis up to about 10 μm (see, for example, synchrotron radiation, vol. 19, 338-348, 2006). Generally, the smaller the scattering angle, the larger the size of the structure can be obtained, and the X-ray scattering at a very small angle is particularly useful in the manufacturing method according to the present invention. In addition, although there is a case where the above-mentioned scattering at the minimum angle is particularly called as a minimum angle X-ray scattering or an ultra small angle X-ray scattering (USAXS) to distinguish it from SAXS, in the present invention, the X-ray small angle scattering or SAX is used. Treats as a measurement method that also includes USAXS without distinction.

The X-ray small angle scattering method can analyze a substance having a relatively low structural regularity as compared with the X-ray diffraction method, and can also perform time-division measurement in milliseconds. Moreover, since the bulk structure can be examined by the high penetrating power of X-rays, the powder contained inside can be analyzed in a non-destructive state even with a thick sample. In addition, when the shape of the powder is known, particularly when it is close to a sphere, the particle size of the powder can be measured from the maximum point or slope of the scattering intensity, and the particle size distribution can be obtained from the extent of the maximum peak. is there. Therefore, it is most suitable for use in the sorting step in recycling or up cycle as in the method of the present invention.

There is no particular limitation on the method for measuring the X-ray small angle scattering, and various known devices can be used. For example, an apparatus using a SPring-8 beam line may be used, and neutron rays may be used instead of X-rays, but it is recommended to use a general-purpose machine of an instrument maker from the viewpoint of cost. Examples include SmartLab and NANOPIXmini manufactured by Rigaku Co., Ltd., but are not limited thereto.

In the sorting step, in addition to sorting the waste resin containing inorganic substance powder by particle size of the powder of inorganic substance, processing for sorting the type of the inorganic substance powder and/or the thermoplastic resin constituting the waste material containing inorganic substance powder-containing resin May be included. For example, apart from analysis by the small angle X-ray scattering method, mid-infrared spectroscopic analysis, near-infrared spectroscopic analysis, infrared spectroscopic analysis, Raman spectroscopic analysis, fluorescent X-ray analysis, X-ray diffraction analysis, etc., and thermal decomposition GC/ It is preferable to perform one kind or two or more kinds of analyzes such as MS analysis and TG/DTA analysis, and select each composition of the resin and/or the inorganic substance powder. By carrying out such an analysis, it is possible to grasp the type and content of the components in the resin waste material, the deterioration state, etc., and to improve the physical properties and moldability of the resin waste material molded body to be manufactured. In particular, if these analyzes are used in combination with X-ray small angle scattering analysis, it is possible to comprehensively understand the composition and condition of resin waste materials, the size of powder contained, etc., leading to a more effective recycling/up cycle of waste materials. Is possible.

[About selection target]
In the method for producing a resin waste material molding of the present invention, the inorganic material powder-blended resin waste material is selected as described above based on the particle size of the inorganic material powder contained therein. The particle size of the resin waste material containing the inorganic substance powder is not particularly limited, and the physical properties and moldability of the target resin waste material molded body and the kind of the available resin waste material are arbitrarily selected. Can be set. For example, by selecting a resin waste material containing an inorganic substance powder having an average particle diameter of 0.1 μm or more, particularly 0.5 μm or more, and further 0.7 μm or more, the resin waste material as a raw material contains almost ultrafine powder. As a result, the increase in torque in the subsequent kneading step and the deterioration of the resin due to the heat generation accompanying it can be prevented. Among the inorganic substance powders, in the case of calcium carbonate or the like, such a selection is particularly important because the ultrafine powder has the effect of reinforcing and thickening the polymer. Alternatively, a resin waste material compact containing no coarse powder can be obtained by selecting a resin waste material containing an inorganic substance powder having an average particle diameter of 13.5 μm or less, particularly 10.0 μm or less. Such selection is important when manufacturing a thin molded product, particularly an inflation sheet or an inflation film.

In the present specification, the average particle diameter means a value calculated from the measurement result of the specific surface area by the air permeation method according to JIS M-8511 unless otherwise specified. Since the measured value of the average particle size often varies depending on the measuring method, a standard sample is prepared for an inorganic substance powder in a resin waste material that is frequently used, for example, a general-purpose inorganic substance powder, and X is measured for each average particle size. It is advisable to perform the measurement by the small angle scattering method or the electron microscope observation and the measurement by the air permeation method, and compare the respective measured values. As a measuring instrument using the air permeation method, for example, a specific surface area measuring device SS-100 type manufactured by Shimadzu Corporation can be preferably used.

<3-2. Crushing process>
The resin waste material thus selected is then crushed into a size of about several mm square. There is no particular limitation on the size to be crushed, for example, 1 to 10 mm square, 1 to 5 mm square, 2 to 3 mm square, 5 to 8 mm square, the type and shape of the target molded product, and the waste material to be used. It can be crushed to a desired size depending on the characteristics of the machine. The crusher is also not particularly limited, and a crusher using a crushing medium such as an impact crusher, a vibration ball mill or a ball mill typified by a planetary ball mill, a roller mill, a jet mill, a disc type or a pin type, etc. A bead mill typified by, a high pressure homogenizer, a medialess disperser typified by an ultrasonic disperser, or the like can be used.

As the pulverizing method, either a dry method or a wet method can be used, and the economical method is preferable from the viewpoint of the dry method and the fact that washing with water can be simultaneously performed. In recycling the resin waste material, it is preferable to wash the waste material, but if the waste material is pulverized by a wet method, it is possible to simultaneously wash with water. From the viewpoint of cleaning efficiency, it is preferable that the cleaning is performed with water after stirring or during grinding with a washing dehydrator or the like while stirring. For example, the recycling efficiency can be improved by combining the dry method and the wet method, performing coarse pulverization by the dry method, and then finely pulverizing by the wet method. After crushing, the foreign matter may be removed using a commercially available foreign matter removing device or the like.

<3-3. Kneading process>
The resin waste material crushed as described above is then subjected to a kneading step. There are many variations in the composition of resin waste materials from suppliers and lots, and in order to produce a resin waste material molded product with good physical properties and to stabilize the quality, multiple resin waste materials are made up of their composition and the inorganic substances contained in them. It is preferable to combine and knead in consideration of the particle size of the powder, the deterioration degree of the resin, and the like. In this process, it is also possible to add and knead the unused resin and/or the inorganic substance powder raw material. It is also possible to add processing aids such as lubricants, plasticizers and dispersants, antiaging agents, antioxidants, UV deterioration inhibitors, softening oils, coupling agents, pigments and other general-purpose agents.

Melting, kneading, and molding of the resin waste material can be performed by any conventionally known method. For example, it may be a method of continuously performing from melting to molding of the resin waste material, or a part or all of each step may be performed discontinuously. However, in the present invention, it is practical from the viewpoint of production efficiency to carry out melting, kneading, and molding or preforming continuously using an extruder. For example, the resin waste material selected and crushed as described above is charged into an extruder, and if necessary, unused raw materials are added, and molded into pellets, sheets, films and the like under arbitrary conditions.

Examples of the extruder include a twin-screw kneading extruder (same-direction rotating twin-screw kneading extruder, different-direction rotating twin-screw kneading extruder), a kneader type extruder, and a single-screw extruder. Among these, the melt mass flow rate at the time of kneading the resin waste material is likely to be high, and the dispersion of the melt mass flow rate is suppressed, and from the viewpoint of good moldability, a kneader type extruder and a twin-screw kneading extruder, particularly A twin-screw kneading extruder is preferred.

<3-4. Molding process>
In the present invention, it is possible to perform kneading and molding or preforming in separate steps. For example, the pellets prepared as described above using a twin-screw kneading extruder can be put into another twin-screw extruder, a single-screw extruder, an injection molding machine or the like to be molded into various shapes. Of course, after kneading with the above-mentioned twin-screw kneading extruder, it is also possible to continuously form a sheet, a film or the like.

In particular, when the shape of the molded product is a sheet, it is more preferable that the wall thickness is 50 μm to 1,000 μm, and further preferably 50 μm to 400 μm. A sheet having a wall thickness within such a range can be suitably used in place of paper or synthetic paper for general printing/information and packaging purposes.

In the production method according to the present invention, it is desirable that the resin waste material molded body is a sheet or film formed by extrusion molding (blow film molding) by an inflation method, that is, a so-called inflation sheet or inflation film. As described above, when the resin waste material contains the inorganic substance powder having a large particle diameter, the surface condition of the molded product is deteriorated and the physical property variation cannot be ignored. These tendencies are particularly remarkable in a thin inflation sheet or inflation film, but in the present invention, since the resin waste material containing such coarse powder is excluded in the sorting step, the surface appearance is excellent, and the mechanical properties are extremely stable. A sheet or film having (tensile strength, elongation, etc.) can be manufactured.

In the case where the molded article according to the present invention is an inflation film, as the film, it is possible to use a dense film, and a high content of the inorganic substance powder, and stretching by air blow of inflation molding. By receiving the fine pores in the film layer, it is possible to obtain a gas permeable gas permeable film.

When the inflation film is a breathable film, the air permeability is preferably 5,000 seconds or more and 85,000 seconds or less, although not particularly limited. The "air permeability" referred to here is a value measured by JIS P8117 (JIS P8117:2009 "Paper and board-Air permeability and air resistance test method (intermediate region)-Gurley method"). More specifically, using a Gurley type air permeability meter conforming to JIS P8117, the time (second) for passing 100 cc of air through the breathable film having an area of 2,500 mm ^{2 in} the atmosphere at 23° C. It was measured, and this was taken as the air permeability (second). The number of seconds is measured by a digital auto counter. The smaller the value of air permeability, the higher the air permeability.

The use of the inflation sheet and the inflation sean film is not particularly limited and can be used in many different uses. Although not particularly limited, for example, hygiene applications, medical applications, healthcare applications, filtration materials, geotextile products, agricultural applications, gardening applications, clothing, footwear products, bag products, household applications, industrial applications, packaging applications, It is used for construction purposes or construction.

Hereinafter, the present invention will be described more specifically based on Examples, but the present invention is not limited to these Examples.

[Example 1]
As a resin waste material containing an inorganic substance powder, a resin scrap "LIMEX" (manufactured by TBM Co., Ltd.) and a similar product (hereinafter, referred to as "resin waste material Nos. 1 to 18") is used as a resin. A waste material compact was manufactured. These resin waste materials No. Nos. 1 to 18 are defective products when polypropylene as a thermoplastic resin and ground calcium carbonate as an inorganic substance powder were kneaded and extruded by an extruder at a mass ratio of 40:60. After the trial molding, 18 types of relatively large size scraps collected in one place in our own factory and stored for about 1 to 6 months were used as raw materials for resin waste materials. For each of the resin waste materials, infrared spectroscopic analysis, X-ray diffraction analysis, and weight reduction rate measurement during firing (500° C.×1 hour) were separately performed, and the polypropylene:calcium carbonate mass ratio was about 40:60. It was confirmed to be a composite material.

Resin waste material No. The X-ray small angle scattering measurement was carried out for 1 to 18 to determine the average particle size of the contained calcium carbonate. NANOPIXmini manufactured by Rigaku Corporation was used as an apparatus, and the average particle size was calculated from the Guinier plot of the measured values. For reference, the same measurement was performed for some of the calcium carbonate raw material powders used for the trial production of "LIMEX" (registered trademark) and its similar products, and the average particle diameter was obtained. Resin waste material No. Table 1 shows the measurement results for Nos. 1 to 18, and the measurement values and catalog values for the calcium carbonate raw material powder showing values close to those.

Separately from the above, the resin waste material No. Approximately 1 g was taken from each of 1 to 18 and calcined in air at 500° C. for 1 hour, and the average particle size of calcium carbonate in each resin waste material was measured using an electron microscope (SEM) image of the obtained powder. did. SEM observation was carried out at 5 places at a magnification of 5,000, and the average particle size was determined from the photographed image using an image analyzer. For reference, the average particle size of some of the calcium carbonate raw material powders used for trial production of "LIMEX" (registered trademark) and its similar products was measured by SEM. The measurement results are also shown in Table 1. In addition, the resin waste material No. The average particle diameter of the fired product of No. 2 was also measured by TEM observation, and the same result as that of SEM observation was obtained.

The average particle size by the air permeation method is often smaller than the measured values by other methods, but the same result was obtained in this measurement. The reason why the average particle size of the calcium carbonate raw material powder b became a value close to 10 times the catalog value in the SEM observation is considered to be that the diameter of the agglomerated secondary particles was measured.

From the above measurement results, the resin waste material No. Since 1, 4, 5, 7, 9, 10, and 15 to 17 were presumed to contain calcium carbonate raw material powders having the same average particle size, these were selected and used at the same mass. Was subjected to the crushing step and the kneading step. The resin waste material was dry-pulverized in a planetary ball mill and then finely pulverized by a wet bead mill to a size of 2 mm square or less. After this was dried, it was kneaded at 200° C. using a co-rotating small biaxial kneading extruder (φ25 mm, L/D=41), extruded into strands in water, cooled and cut to produce pellets.

Using the pellets thus obtained, a film was produced on an inflation film extrusion line (60 mm circular die, 1.2 mm die gap, 30 mm screw diameter, L/D ratio=30). The film was treated with a BUR (blow-up ratio) of 3.0 to keep the frost line height at a height of 16 cm (distance from the die). In the extruder, the temperature of each area was set to 190°C to 230°C. The extruder speed was always maintained at 60 rpm and the basis weight of the film was set at 35 g/m ² by appropriate adjustment of the line speed. Also, the cooling air flow was adjusted accordingly to keep the frost line in the same position. The produced blown film was a good product with a smooth appearance and no discoloration or thickness variation.

[Comparative Example 1]
The above resin waste material No. Pellets were prepared in the same manner as in Example 1 except that 1 to 18 were used in the same mass without selection. At the time of kneading, an effort was made to control the temperature of the extruder to be about 200°C, but the torque rise and heat generation during kneading were remarkable, and a temperature temporarily exceeding 240°C was also observed.

When the obtained pellets were molded in the same manner as in Example 1, an inflation film having a reddish and uneven thickness was produced. It is known that ultrafine calcium carbonate having an average particle diameter of 0.1 μm or less has a reinforcing effect on the polymer and causes an increase in viscosity of the melt-kneaded product. The resin waste material No. 1 was not sorted according to the particle size of the inorganic substance powder. In this comparative example using all 1 to 18, the torque of the extruder was increased by the action of the ultrafine calcium carbonate, the polypropylene component was deteriorated due to the heat generated thereby, the film was reddened, and the viscosity of the melt was increased. It is thought that this caused the variation in the wall thickness.

[Example 2]
In Comparative Example 1, it was shown that the kneading by the small-sized extruder used this time may increase the torque and the molten resin temperature due to the ultrafine calcium carbonate. Therefore, such resin waste material containing calcium carbonate was excluded. Then, the production of an inflation film was tried. Screening was performed based on the measurement results in Example 1, and the resin waste material No. An inflation film was produced in the same manner as in Example 1 except that 2, 6, 11 to 13 and 18 were excluded, and the other resin waste materials were used in the same mass. The blown film obtained was a good product with a smooth appearance and no discoloration or thickness variation. In addition, the inflation film obtained in this example had a slightly flatter feel than the inflation film of Example 1. In the resin waste material containing the inorganic substance powder used in this example, the particle size distribution of calcium carbonate contained therein is wider than that of the resin waste material of Example 1, and the content ratio of calcium carbonate having a small particle size is relatively small. It is possible that the reinforcing effect of the filler filling did not appear to be large.

From the above, when the resin waste material mixed with the inorganic substance powder is recycled and the resin waste material molded body containing the thermoplastic resin and the inorganic substance powder is manufactured, the resin waste material mixed with the inorganic substance powder is selected according to the particle diameter of the inorganic substance powder. Was shown to be important. In particular, in the measurement by the X-ray small angle scattering method, it was possible to accurately determine the presence or absence of the ultrafine powder without being disturbed by the agglomeration. This method does not require measurement pretreatment such as firing, does not cause aggregation of the inorganic substance powder accompanying pretreatment, and has the advantage of being able to analyze a wide range of areas as compared with an electron microscope. It is considered to be extremely useful in the selection process of. The X-ray small-angle scattering device NANOPIXmini used this time has a maximum measurable particle size of 1 μm, but if a device capable of ultra-small-angle scattering measurement is used, the resin waste material No. It is considered that the average particle size of calcium carbonate contained in 3 etc. could be measured. For reference, Table 2 shows the characteristics of each analysis method and the obtained film.

[Example 3 and Comparative Example 2]
The above resin waste material No. Resin waste material No. 1 stored in a place different from 1 to 18 for about 3 months. 19 to 24 were used to produce a resin waste material molded body. These resin waste materials No. Nos. 19 to 24 are defective products when polyethylene as a thermoplastic resin and heavy calcium carbonate as an inorganic substance powder were kneaded and extruded by an extruder at a mass ratio of 20:80. The composition of each waste material was confirmed by infrared spectroscopic analysis or the like as in Example 1.

With respect to the resin waste material, the average particle size was measured using an SEM image in the same manner as in Example 1. Table 3 shows the measurement results of the respective resin waste materials, and the measurement values and catalog values of the calcium carbonate raw material powder showing values close to those.

From the above analysis results, the resin waste material No. Since it was estimated that 19, 21, 22, and 24 contained calcium carbonate raw material powders having the same average particle diameter, these were selected and used in the same mass. To 100 parts by mass of these resin waste materials, 20 parts by mass of an unused polyethylene resin (Novatech HD-HY420 manufactured by Nippon Polyethylene Co., Ltd.) was added and kneaded in the same manner as in Example 1 to obtain a mass ratio of polyethylene:calcium carbonate. 1:2 was produced (Example 3).

For comparison, the resin waste material No. The pellets were produced in the same manner as in Example 3 by using 19 to 24 in the same mass without selection (Comparative Example 2).

An inflation film was produced in the same manner as in Example 1 using these pellets. According to the present invention, an inflation film having a good appearance and no variation in thickness was obtained from the pellets produced by selecting the resin waste material based on the particle size of the inorganic substance (calcium carbonate) powder contained. On the other hand, in Comparative Example 2 in which the resin waste material was manufactured without being sorted according to the particle size of the inorganic substance powder, the surface condition was poor despite the addition of the unused polyethylene, and a film having a different tactile sensation for each site was produced. It is presumed that, as a result of not selecting the resin waste material, calcium carbonate having a remarkably different particle diameter was mixed into the molded body, which locally deteriorated the surface condition. When the film was pulled by hand, some parts were easily cracked. Resin waste material No. It is considered that the coarse calcium carbonate particles in 20 and 23 having an average particle size of more than 13.5 μm cause the deterioration of the surface state and the starting point of cracking. When manufacturing a resin waste material molded body containing a thermoplastic resin and an inorganic material powder, the importance of selecting the resin waste material mixed with the inorganic material powder according to the particle diameter of the inorganic material powder was shown again.

Claims (10)

A method for producing a resin waste material molded body comprising inorganic material powder blending resin waste material and a thermoplastic resin and calcium carbonate comprising calcium carbonate, the carbonate contained the inorganic substance powder compounded resin waste material to inorganic material powder blended resin waste material A method for producing a resin waste material molded article, comprising: a selection step of selecting according to the particle size of calcium , a pulverization step of crushing the selected inorganic material powder-blended resin waste material, and a kneading step of kneading with an extruder. The method for producing a resin waste material molding according to claim 1, wherein the particle diameter of the inorganic substance powder is measured by the X-ray small angle scattering method in the sorting step. The method for producing a resin waste material molded body according to claim 1, wherein the thermoplastic resin contains a polyolefin resin. The method for producing a resin waste material molding according to claim 1, wherein the thermoplastic resin contains a polypropylene resin. The resin waste material molded product, a thermoplastic resin and an inorganic material powder and 50: 50-10: including in a weight ratio of 90, the production method of the resin waste material molded article according to any one of claims 1-4. The method for producing a resin waste material compact according to any one of claims 1 to 5, wherein the calcium carbonate contained in the resin waste material compact has an average particle diameter of 0.5 µm or more and 13.5 µm or less by an air permeation method. .. The kneading step comprises the step of kneading twin-screw extruder, the production method of the resin waste material molded article according to any one of claims 1-6. The screening step is performed by one or more analysis methods selected from mid-infrared spectroscopy, near-infrared spectroscopy, infrared spectroscopy, Raman spectroscopy, fluorescent X-ray analysis, and X-ray diffraction analysis. further comprising selecting the type of resin and / or an inorganic material powder, method for producing a resin waste material molded article according to any one of claims 1-7. The resin waste material molded product is a resin pellet manufacturing method of the resin waste material molded article according to any one of claims 1-8. The resin waste material molded body is blown sheet or blown film, method for producing a resin waste material molded article according to any one of claims 1-8.