JP7343884B1 - Blue coloring material composition for blue recycled resin composition, blue recycled resin composition, blue recycled cable tie for packaging, and manufacturing method of blue recycled cable tie for packaging - Google Patents

Abstract

[Problem] When manufacturing a blue reproduction band that accounts for about 70%, even if the chroma of the raw material mixed color reproduction pellets is relatively low, it is possible to reliably provide a blue reproduction band with a chroma of 20 or more. do. [Solution] A blue coloring material composition for a blue recycled resin composition according to the present invention contains a first pigment having a hue angle of 240° to 255° and titanium dioxide, based on 100 parts by mass of the first pigment. The content of titanium dioxide is 10 parts by mass to 50 parts by mass. By mixing the above masterbatch in a predetermined ratio with a blue recycled base material obtained by classifying a plurality of used packaging cable ties with different hues and/or materials into blue groups, and stretching the mixture, blue packaging bands can be produced. We can manufacture recycled cable ties. [Selection diagram] None

Description

The present invention relates to a blue coloring material composition for a recycled blue resin composition, a recycled blue resin composition, a recycled blue binding band for packaging, and a method for producing a recycled blue binding band for packaging.

Packaging cable ties used for packaging are mainly composed of polypropylene (hereinafter also referred to as "PP") or polyethylene terephthalate (hereinafter also referred to as "PET"), which is formed into a belt shape with the addition of auxiliary materials such as pigments. , a band with a width of 5 mm to 25 mm manufactured by applying a continuous diamond-shaped uneven pattern (embossed) to the surface. There are various colors and sizes depending on the purpose, and the amount used in Japan is about 40,000 tons. However, because they are not subject to separate collection under the Containers and Packaging Recycling Law, they are mostly disposed of by incineration, etc., without being recycled.

PP bands, which account for about 80% of commercially available packing ties, come in colors such as blue, yellow, white, transparent, red, green, and black. It is recovered as a mixture of the PP band and the PET band.

Currently, recycled cable ties made from recovered cable tie mixtures of various colors are on the market. The most commonly used cable tie is blue, and the second most commonly used is yellow, so even for recycled cable ties, we recommend using cable ties in blue, yellow, etc. that have the same hue as new cable ties (virgin bands). provided. However, in industrial production where productivity is important, it is extremely difficult to eliminate the contamination of colors other than the target color, such as black, by either mechanical color separation or manual color separation. As a result, the recycled cable ties end up with various colors due to color mixing, and the recovered pellets are inevitably manufactured to include a small amount of multiple colors, black, etc. in the target color. The color of packaging cable ties plays an important role not only in aesthetics but also in functionality. For example, the color of packaging cable ties is used for product classification of packaged products and inventory management. Therefore, coloring with high saturation in various hues is extremely important so that such information can be distinguished at a glance. However, as mentioned above, conventional recycled cable ties are achromatic or have extremely low saturation, making it difficult to distinguish them. It was lacking, and its uses were extremely limited.

Now, a recycled PP band is produced from this mixed color recycled pellet, but in order for this to be recognized as a blue recycled band or a yellow recycled band, it goes without saying that each of them must have clear target color distinguishability in terms of appearance. No. The target color identifiability of this colored reproduction band is defined by saturation (see Patent Document 1).

JP2020-090656A

However, it is not necessarily easy to stably produce a blue reproduction band with a chroma of 15 or more using, for example, mixed-color pellets in which yellow, black, etc. are mixed with the blue recovered product as a starting material. For example, it is not easy to reliably provide a blue reproduction band with a saturation of 15 or more with mixed color pellets in which the mixed ratio of black or the like is relatively high and the saturation of the recovered pellet primary color is extremely low.

The purpose of the present invention is to produce a blue reproduction band with a saturation of 15 or more even when the chroma of the mixed color reproduction pellets used as the raw material is relatively low when manufacturing a blue reproduction band that accounts for about 70%. It is important to ensure that this is provided.

As a result of intensive studies to solve the above problems, the present inventors discovered that the above objects could be achieved by using a colorant composition containing an ultramarine pigment and titanium dioxide, and in order to complete the present invention. It's arrived. Specifically, the present invention provides the following.

The invention according to the first feature contains a first pigment having a hue angle of 240° to 255° as defined in the CIE 1976 color system, and titanium dioxide, wherein the amount of titanium dioxide per 100 parts by mass of the first pigment is Provided is a blue colorant composition for a blue recycled resin composition, the content of which is 10 parts by mass or more and less than 50 parts by mass.

FIG. 1 illustrates the a ^* value and b ^* value defined in the CIE 1976 color system for each band color for a new binding band (virgin band). In the new blue cable ties on the market, the hue angle h defined by tan ^-1 (b ^* /a ^* ) is 275° to 285°, and the new blue cable ties have L ^* as shown in FIG. Located in the fourth quadrant of the a ^* b ^* plane.

In addition, among the collected used cable ties, only used blue cable ties were collected.
The average chroma C ^* defined by C* was 24.34, which is significantly lower than the chroma of cut products made of only yellow cable ties. When only used blue cable ties are collected at the laboratory level, the saturation is 24.34, which is slightly higher than 20, so the saturation is 24.34, which is slightly higher than 20, so the saturation is 24.34, which is slightly higher than 20. Therefore, the saturation is 24.34, which is slightly higher than 20. It is not easy to achieve a color saturation of 15 or higher, which is close to the saturation.

According to the invention related to the first feature, the first pigment (ulmarine pigment) having a hue angle of 240° to 255° causes the chroma of the mixed color pellet to be low, and even if it contains black, it will not be affected by the black contamination. The loss of blue color can be suppressed to a small level, and the black color mixed in can be blocked by titanium dioxide. Therefore, the saturation of the blue regenerated resin composition can be increased with a minimum number of complementary colors, and as a result, a blue regenerated resin composition having a saturation of 15 or more can be provided.

Note that blue pigments include not only the first pigment (ulmarine pigment) but also ultramarine (hue angle: 234°), azurite (azurite, hue angle: 220°), and deep blue (Prussian blue, hue angle: 220°). ), cobalt blue (cobalt aluminate, hue angle: 200°), cerulean blue (cobalt stannate, hue angle: 197°), and phthalocyanine blue (hue angle: 275° to 285°). However, all of these blue pigments lose more blue color due to black contamination than the first pigment. Therefore, using only a complementary color using a blue pigment other than the first pigment or a mixture of these blue pigments may result in a relatively large amount of pigment used, which is not preferable.

In addition, white pigments include not only titanium dioxide (titanium white), but also zinc oxide (also called zinc white, zinc white), a mixture of barium sulfate and zinc sulfide (lithopone), and basic lead carbonate ( _2PbCO3 . Pb(OH) ₂ , lead white), etc. are also known. However, all of these white pigments are poorer in blocking black color than titanium dioxide. Therefore, using only a complementary color using a white pigment other than titanium dioxide (preferably rutile type titanium dioxide) or a mixture of these white pigments may result in a relatively large amount of the pigment used, which is not preferable.

The invention according to the second characteristic is the invention according to the first characteristic, further comprising a second pigment having the hue angle of 275° to 285°, and wherein the second pigment has a hue angle of 275° to 285°. A masterbatch having a pigment content of 15 parts by mass or more and 30 parts by mass or less is provided.

According to the invention according to the second feature, since a complementary color effect is obtained by both the first pigment (ulmarine blue pigment) and the second pigment (phthalocyanine blue pigment), the loss of blue color due to black contamination in the mixed color pellet is further reduced. It can be suppressed.

The invention according to the third feature is characterized in that the main component is polyolefin and/or polyethylene terephthalate obtained by recycling a plurality of used packaging cable ties with different hues and materials, and the hue angle is 240° to 300°. Containing a certain blue recycled base material and a coloring material composition according to the first or second feature, a total of 100 mass of the blue recycled base material and a carrier resin included as an optional component in the coloring material composition. The ratio of the coloring material composition to the parts is 0.5 parts by mass or more and 2 parts by mass or less, and the chroma C ^* is 15 or more in the CIE 1976 color system when the spectral reflection characteristics are measured as a resin plate with a film thickness of 2 mm. Provided is a blue recycled resin composition having the following.

The invention according to the fourth feature is a product mainly composed of polyolefin and/or polyethylene terephthalate, which is obtained by recycling a plurality of used packaging cable ties having different hues and materials, and which has a hue angle defined in the CIE 1976 color system. a blue reproduction base material whose hue angle is from 240° to 300°, a first pigment whose hue angle is from 240° to 255°, and titanium dioxide; The present invention provides a blue recycled resin composition in which the proportion of one pigment is 0.5 parts by mass or more and 2 parts by mass or less, and the proportion of titanium dioxide is 0.05 parts by mass or more and less than 0.5 parts by mass.

The invention according to the fifth aspect provides a recycled blue binding band for packaging, which is made of a cured product of the recycled blue resin composition according to the third or fourth aspect.

The invention according to the sixth feature includes a color sorting step of preparing a blue mixture by classifying a plurality of used packaging cable ties having different hues and/or materials into blue groups, and melt-kneading and/or glazing the blue mixture. a step of mixing the colorant composition according to the first or second feature with 100 parts by mass of the blue recycled base material obtained through the processing step of converting the blue recycled resin composition into a blue recycled resin composition; the coloring material composition for a total of 100 parts by mass of the blue recycled base material and the carrier resin contained as an optional component in the coloring material composition. The proportion of is 0.5 parts by mass or more and 2 parts by mass or less, and the blue recycled cable tie for packaging has a chroma of 15 or more in the CIE 1976 color system when the spectral reflection characteristics are measured as a resin plate with a film thickness of 2 mm. Provided is a method for manufacturing a blue recycled cable tie for packaging, which has C ^* .

The invention according to the seventh feature includes a color sorting step of preparing a blue mixture by classifying a plurality of used packaging cable ties having different hues and/or materials into blue groups, and melt-kneading and/or glazing the blue mixture. A first pigment having a hue angle of 240° to 255° as defined in the CIE 1976 color system, titanium dioxide, and optionally a first pigment having a hue angle of 275° 285° to obtain a blue recycled resin composition; and a step of stretch-molding the blue recycled resin composition to obtain a blue recycled cable tie for packaging. With respect to 100 parts by mass of the recycled base material, the proportion of the first pigment is 0.5 parts by mass or more and 2 parts by mass or less, and the proportion of the titanium dioxide is 0.05 parts by mass or more and less than 0.5 parts by mass, The proportion of the second pigment is 0 parts by mass or more and 0.6 parts by mass or less, and the blue recycled cable tie for packaging has a spectral reflection characteristic of 15 in the CIE1976 color system when measured as a resin plate with a film thickness of 2 mm. Provided is a method for producing a blue regenerated cable tie for packaging having the above chroma C ^* .

When recycling used cable ties collected from the market, especially when manually sorting, the chroma of mixed color pellets is low and it is virtually impossible to provide a blue recycled resin composition with a chroma of 15 or more. It was thought that there was.

According to the invention according to the third to seventh characteristics, whether recycling is done manually or mechanically, a considerable amount of low-colored pellets of black or other colors is used as a raw material, and high-quality pellets with a saturation of 15 or more are used. It is possible to provide a high quality recycled blue resin composition and a recycled blue cable tie for packaging.

Here, the third and fourth inventions are in the form of product-by-process claims. Because packing ties have a clear purpose, the amount of foreign substances such as metals and inorganic substances contained in recovered products is smaller than that of general recovered resin products. However, since packaging cable ties are placed in various environments when transporting and storing packages, there are a wide variety of contaminants such as metals and inorganic substances contained in recovered products, and the types and types of contaminants in extremely small amounts vary. It is not practical to accurately identify and quantify the amount.

Generally, in order to analyze minute amounts of impurities such as metals contained in resin, a method is known in which the resin is dissolved in a solvent, the solution is subjected to extraction using water, and the impurities are concentrated. However, since the resin composition of the present invention mainly contains a highly crystalline resin such as polypropylene or polyethylene terephthalate, the solvents that can dissolve these resins are extremely limited. The solvent for dissolving such highly crystalline resins is extremely special. For example, decalin is known as a solvent for dissolving polypropylene, but it cannot be dissolved unless it is at a high temperature of 100°C or higher. Even if it could be prepared, it is extremely difficult to concentrate impurities by subjecting a decalin solution at 100° C. or higher to extraction with water.

Therefore, in the third and fourth inventions, there is a situation where the "product" cannot be specified without using the description of the manufacturing method, so even if the description is in the product-by-process format, it is not unclear.

According to the present invention, it is possible to increase the saturation of a blue recycled resin composition with a minimum number of complementary colors, and as a result, it is possible to provide a blue recycled resin composition and a blue recycled binding band for packaging that have a saturation of 15 or more.

FIG. 1 illustrates the a ^* value and b ^* value defined in the CIE 1976 color system for each band color for a new binding band (virgin band).

Hereinafter, an example of a preferred form for carrying out the present invention will be described with reference to the drawings. Note that this is just an example, and the technical scope of the present invention is not limited to this.

<Manufacturing method of blue recycled cable ties for packaging>
In the present embodiment, the method for producing a recycled blue packing band includes the steps of producing a blue recycled resin composition using a plurality of used packing bands having different hues and/or materials as raw materials, and and a step of stretch-molding the object.

[Process of producing blue recycled resin composition]
The process of producing a blue recycled resin composition includes a color sorting process of classifying a plurality of used packaging cable ties with different hues and/or materials into blue groups to prepare a blue mixture, and a process of melt-kneading and melt-kneading the blue mixture. and/or a processing step of turning into a glaze.

[Used packaging ties]
The manufacturing method of the present invention uses a used packing band as a raw material. Binding ties for packaging are mainly made of polypropylene (PP) and/or polyethylene terephthalate (PET), and after adding auxiliary materials such as pigments and forming them into a band shape, the surface is embossed with a continuous diamond-shaped pattern. This is a band with a width of 5 mm to 25 mm manufactured by applying this process. Note that in the present invention, X to Y includes X and Y, which are the end values thereof. For example, the expression "5 mm to 25 mm" means 5 mm or more and 25 mm or less, and includes the extreme values of 5 mm and 25 mm.

In general, recovered raw materials are broadly classified into pre-consumer materials (raw materials) and post-consumer materials (raw materials). Pre-consumer materials are recovered from the manufacturing process and are in a state before they are made into products, so they contain almost no dirt or impurities. On the other hand, post-consumer materials are collected from products once used in the market, that is, collected from the market, and therefore contain dirt and impurities and are much more difficult to recycle than the former. However, the present invention is effective even when post-consumer materials are used as binding bands for used packaging.

Since packing ties are usually used alone for packaging, they are relatively easy to separate even if they are post-consumer materials. However, because some PET bands are used along with PP bands, contaminants may be mixed in depending on the usage environment, and the degree of dirt and deterioration over time and damage during use varies, etc., the usage history is as much as possible. It is preferable to use used packing ties that are clear and contain less contaminants. For example, in the newspaper industry, packing ties are used for packaging from printing plants to newspaper distributors, but because they are used in limited environments with cooperation within the industry, their usage history is clear, and they contain contaminants. The degree of contamination and dirt is small, and there is little deterioration or damage over time. Therefore, a collection route suitable for horizontal recycling of packaging cable ties has been established in the newspaper industry. Similarly, packaging ties used for packaging beverage containers, processed foods, clothing, publications/printed materials, precision parts, building interior parts, and large home appliances are also used between factories and between factories and warehouses, wholesalers, and stores. Since the usage history is relatively clear throughout the entire distribution process, such as between factories and stores, it is possible to form collection routes suitable for horizontal recycling in this industry as well. On the other hand, packaging cable ties, which are collected together with used paper such as cardboard in the shipping industry, have various usage histories, but most of them are single-use in normal distribution routes, and the amount collected is large. Since impurities and dirt are also reduced, it is useful as a raw material for the present invention. Furthermore, in the future, if a separate collection route for PET bottles from households is established, packaging ties used in the shipping industry could become a more useful raw material.

[Pre-treatment process]
It is preferable to pre-treat the used packing ties before the color sorting step.

((cooling process, heating process))
In order to make it easier to cut the used packaging binding band, it is preferable to provide a step of cooling or heating the used packaging binding band. Specifically, cooling to a temperature below the embrittlement temperature of PP or PET can be mentioned. In particular, used PP packaging ties are preferably cooled to -20°C or lower. It is also preferable to heat used packing ties to 130° C. to 200° C. to soften them and make them easier to cut. The heating temperature is more preferably 140°C to 190°C, even more preferably 150°C to 180°C.

((cutting process))
This may be followed by a cutting step in which the used packaging cable ties are cut to obtain a cutting mixture. By using cut used packaging binding bands, the accuracy of transfer by the sorting section can be increased, so yield and sorting accuracy can be improved. It is preferable that the plurality of cut used packaging cable ties are arranged on the conveyor so that they do not overlap with each other. This means, for example, feeding cut used packaging cable ties onto a conveyor while avoiding tangles and overlaps by hand, or installing protrusions on the way down so that they spread out and fall onto the conveyor when they are put in. This can be accomplished by feeding cut used packaging ties onto a conveyor using a disc spreader. Preferably, the cutting mixture has a length distribution in which 95% of the total weight lies in the range 5 mm to 800 mm. The range is more preferably 10 mm to 600 mm, and still more preferably 20 mm to 400 mm. When the central value of the length of the cut piece is L50, L50 is preferably 10 mm to 500 mm, more preferably 20 mm to 500 mm, still more preferably 30 mm to 400 mm, and particularly preferably 40 mm to 300 mm. Further, the pitch of the air nozzle is usually about 20 mm to 30 mm, but if this is reduced to about half, it becomes possible to sort small objects, but in this case, from the viewpoint of cost and accuracy, the L50 is preferably 5 mm. ~400 mm, more preferably 10 mm ~ 300 mm.

If used packaging cable ties are not cut cleanly and are torn off or cracked in the vertical direction, there will be many thread-like cut pieces and hangnails, which will intertwine with each other and reduce sorting accuracy. be. To prevent this, it is preferable to optimize the cutting machine and cutting conditions. Examples of the cutting machine include a cutting machine, a twin-shaft crusher, a single-shaft crusher, and the like. A cutting machine is a device that cuts an object by pushing it through with a linear blade, and a crusher is a device that cuts and crushes an object by tearing it with the shear force of at least two rotating blades. A single-shaft crusher is preferred in terms of work efficiency, ease of adjusting the size of cut pieces, and ease of maintenance. Further, a cutting machine is preferable from the viewpoint of ease of controlling the length of the cut pieces and from the viewpoint of not producing cut pieces that are finely broken into threads. In a single-shaft crusher, the size of the cut pieces is adjusted by the hole size of the screen. From the viewpoint of obtaining good cut pieces with a length suitable for an optical sorter, a hole size larger than the around 50 mm used for general crushing is preferable, specifically a diameter of 50 mm or more is preferable, and a diameter of 70 mm is more preferable. Preferably, 90 mm to 140 mm is more preferable. When feeding used packaging binding bands into a cutting machine, it is preferable to remove black binding bands, which have a large negative effect on color saturation.

((Contaminant removal process))
Subsequently, it is preferable to provide a step of removing foreign matter from the cut used packing ties. This process involves the removal of impurities by visual inspection by the operator; the detection and removal of metals using magnetic force; the submergence removal that separates stones, sand, and metal pieces that have a higher specific gravity than water; the removal of dust, minute components, films, etc. , air removal by blowing away using gas; water cleaning by a cleaning device driven by at least one means selected from the group consisting of propellers, screws, vibrations, ultrasonic waves, and high-pressure jets; by a filter installed in the extruder Examples include removal of unmelted materials. A plurality of these methods can be combined.

Removal by magnetic force is preferably carried out at the end of a conveyor that conveys the cut used packaging binding bands or their cut pieces. This process allows metals such as iron to be removed. A metal detection sensor that uses magnetic force is placed inside the conveyor roller at the end of the conveyor, and if metal is detected, the conveyor path is changed or it is flicked out using air pressure, etc. to eliminate crushed pieces containing metal. can do. Adsorption and removal using magnetic force may also be performed.

In water submergence removal, stones, sand, metal pieces, and resin pieces (for example, PET resin pieces (specific gravity: 1.27)), which have a higher specific gravity than water, can be efficiently removed. Water precipitation removal, water washing, dewatering, and drying may be combined as a series of devices.

In the method using a filter equipped on an extruder, it is preferable to use a filter of 40 mesh to 150 mesh, more preferably 60 mesh to 120 mesh, and still more preferably 80 mesh to 100 mesh. In the case of used PP packing ties, the temperature setting of the extruder is preferably 170°C to 280°C, more preferably 180°C to 230°C. If the set temperature is raised, production efficiency will improve, but if it exceeds 230°C, other resins may also melt, making removal difficult. For example, if polyamide (PA) is mixed as an impurity in a used PP packaging binding band and kneaded at 230° C. or lower, the PA will not melt and can be removed using a mesh. However, when kneading is carried out at about 280° C., PA also melts and is mixed into the recycled resin composition, but since PA is not compatible with PP, the physical properties of the recycled resin composition deteriorate. Furthermore, this method can also remove inorganic substances that cannot be removed by methods using magnetic force. The strands may be passed through an extruder and have a diameter of about 2.7 mm to 4.5 mm, and then pelletized using a pelletizer.

[Color sorting process]
In the present invention, the color sorting step is not particularly limited as long as it selects used packaging ties from a plurality of used packaging ties, and may be mechanical sorting or manual sorting. Visual selection may also be used. The case of mechanical sorting will be explained below.

In mechanical sorting, an optical sorter is used to sort used packaging cable ties into one or more color groups selected from the group consisting of blue, yellow, red, white, and green, and a blue mixture is selected. Equipped with That is, a blue mixture, a yellow mixture, a red mixture, a white mixture, or a green mixture is prepared by this step, and the blue mixture is extracted therefrom. The blue mixture is a mixture of used packaging cable ties that are determined to belong to the blue color based on certain criteria described below.

The optical sorting machine includes a sensor unit that collects color information or an optical spectrum from an object being transported, and a sorting unit that works in conjunction with the sensor to separate the object into appropriate color groups. Preferably, the sensor section has a function of irradiating the object with visible light or near-infrared light, and a function of receiving the reflected light and photoelectrically converting it into an electric signal for each color. In particular, packing ties have uneven surfaces that tend to cause light to be scattered, but this effect can be minimized by using reflected light. In addition to this, the sensor section preferably has a function of acquiring an infrared absorption spectrum of the object. Preferably, the sorting section has a function of transporting objects by color based on information from the sensor section. For example, the objects can be transferred to color-coded receivers by applying air to them. In this device, the air nozzles are preferably placed above and below the conveyor, with air from the upper nozzle transporting the object to a receiver located closer to the conveyor, and air from the lower nozzle transporting the object to a receiver located farther from the conveyor. When air is not supplied from the nozzle, the object can be placed in a container at an intermediate position. By turning on/off the upper and lower nozzles, the used packing ties can be sorted into two to three color groups in one sorting. In the optical sorting machine, there is a one-to-one correspondence between detection by the sensor and transfer by the sorting section.

It is preferable that color selection be performed most efficiently from the viewpoint of usage amount and color engineering. Commercially available PP packing ties come in a variety of colors such as blue, yellow, white, transparent, red, green, and black, but blue, yellow, white, or transparent are used the most in that order. Approximately 60% to 70% of recovered items are recycled as blue.

Furthermore, from the perspective of color engineering, even if white and transparent colors are mixed, they have little effect on other colors. Therefore, when producing recycled resin compositions with colors other than white and transparent, the permissible amounts of white mixtures and transparent color mixtures are large, so that the white mixture and transparent color mixture are given low priority in sorting. On the other hand, when producing a white recycled resin composition, the mixing of other color mixtures has a large effect on the hue, so the selection priority for other color mixtures is high. Similarly, the influence of yellow contamination on red and green colors is small, so when producing red recycled resin compositions or green recycled resin compositions, the allowable amount of yellow mixture is relatively large, so yellow mixtures are selected. Low priority. On the other hand, when producing a yellow recycled resin composition, it is necessary to reduce the contamination of other colors as much as possible, so the selection priority for mixtures of other colors is high. From the above, it is particularly preferable to preferentially sort yellow mixtures, blue mixtures, and white or transparent mixtures in this order from the used packing ties.

On the other hand, black is a color that should be selected with the highest priority because color mixture causes a large decrease in both brightness and saturation and greatly deteriorates distinguishability. However, in normal optical sorting machines, the color of the conveyor used to transport the items to be sorted is black or dark gray, making it difficult to detect and sort black packing ties during the color sorting process. As a result, black is mixed into the target colors to be sorted, resulting in a decrease in saturation. In order to solve this problem, it is preferable to reduce the contamination of black color as much as possible in a process before the color sorting process. Specific methods include (i) a method of making the color of the conveyor white or a chromatic color, such as green, yellow, or white, so that black can be detected by an optical sorter, especially for non-black conveyors; A two-step color sorting method in which black is removed using an optical sorter using an optical sorter, and then colors are sorted using a regular black conveyor. Preferably, the black material is removed manually from the container, or (iii) the black packing band is removed when collecting the used packing band. Among them, (ii) manual black removal method is practical and preferable at present, but in the future when awareness of recycling increases and a society where separate collection is a given becomes a reality, (iii) is the most preferable.

The above-mentioned color sorting process is a key process in order to efficiently obtain high-visibility, highly saturated packaging ties by horizontally recycling used packaging ties. In color sorting using an optical sorter, the spectral characteristics of recovered samples of various colors to be sorted are loaded into the sorter in advance and are registered in color groups to be sorted, such as blue, yellow, red, and green. Therefore, for example, the color characteristics such as color and saturation of the recycled cable ties obtained, as well as the recycling rate, are greatly affected by whether orange is sorted into yellow, red, or grouped as an independent group. . From the viewpoint of identifiability and economy, it is preferable to treat white, green, and red, including yellow, blue, and transparent, as one group, respectively, and intermediate colors such as orange, yellow-green, purple, and brown to be treated as one group. It is preferable to treat it as either color. The sensitivity with which an optical sorter recognizes colors is also important in increasing color selectivity. This can be adjusted by enlarging or reducing the minimum area (pixel) that picks up reflected light from the sample to be sorted. By specifying color groups divided by spectral characteristics and adjusting the sensitivity of the optical color sorter, desired color sorting becomes possible.

The collected packaging cable ties are color-sorted by the above method, but if one color sorting is not enough, the sorting may be repeated a plurality of times. When sorting is repeated multiple times, one optical sorter may be divided into two and used for two different sorting operations, or a plurality of optical sorters may be used, but the latter is more preferable. In the former case, the input section, conveyor section, and receiver can also be divided into two parts. For example, after the black mixture is sorted out from the used packing ties, the yellow mixture or the blue mixture is sorted out. After sorting out the yellow mixture and the blue mixture, the green mixture and the red mixture are further sorted out from the remaining used packing ties. From the perspective of increasing the completeness of horizontal recycling, including economic efficiency, it is desirable to have a recycling rate close to 100%.To achieve this, it is necessary to sort out and remove used packing ties and fine cut pieces that remain unsorted. It is preferable to use it as a raw material for a black reclaimed resin composition together with the black mixture.

When prioritizing the sorting in this way, the sorting accuracy can be further improved by optimizing the positional relationship between the desired color mixture and the receiver. The transfer accuracy of the sorting section is higher when transferring to a receiver located further away than the conveyor because air pressure can be used more effectively. Therefore, in the second and subsequent sorting, it is preferable to transfer used packing ties of colors other than the intended color to a receiver at a distant location. For example, in the first sorting, a yellow mixture, a blue mixture, and the rest are sorted, the yellow mixture or the blue mixture is subjected to a second sorting, and the used packaging cable ties of colors other than the intended ones are placed in a remote location. It is more preferable to transfer it to a container and remove it.

The accuracy of color sorting is determined by preparing a flat sample from the sorted mixture of the same color, measuring the L ^* , a ^* , b ^* values based on the color system standard using a color difference meter, and calculating the hue angle, C ^* The value is calculated and evaluated based on hue and saturation. The hue angles of commercially available PP packing ties are as follows.
Yellow (commercial flat sample): 80° to 100°
Blue (commercial flat sample): 270° to 280°
Red (commercial flat plate sample): 40° to 50°
Green (commercial flat sample): 170° to 190°

Among the collected used cable ties, the chroma C ^* of cut products made from only used cable ties is generally 25 or higher for yellow, red, and green, but the saturation of blue is higher than that of other colors. It is about 24, which is smaller than the saturation of .

[Material selection process]
In the color sorting step, or before or after the color sorting step, a step may be provided to sort a plurality of used packaging cable ties into a mixture containing PP as a main component and a mixture containing PET as a main component. For example, by the above-mentioned submergence removal, it is possible to separate used PP packing ties having a specific gravity of about 0.93 and used PET packing ties having a specific gravity of about 1.27. Specific gravity sorting, water washing, dehydration, and drying may be combined as a series of devices. For material sorting, a known specific gravity sorting device can be used, but a hydrocyclone method described in International Publication No. 98/41374 can also be used. The selected mixture is dried by heating, blowing air, centrifugal dehydration, etc.

In this embodiment, the main component means the component with no other components or, if there are other components, the component with the largest amount. The proportion of the main component is 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more, based on 100 parts by mass of the resin component contained in the used packaging binding band. , more preferably 95% by mass or more, and particularly preferably 99% by mass or more.

[Processing process]
In this step, the mixture of the same color is melt-kneaded or glazed. Glazing is the process of reducing the volume of an object using frictional heat and shear insulation. It is preferable that melt-kneading and glancing are performed for each mixture of the same color. For example, a blue mixture and a yellow mixture are melt-kneaded separately. However, a plurality of different mixtures of the same color may be melt-kneaded to the extent that the saturation is not impaired.

The extruder used for melt-kneading may be a single-screw extruder, a twin-screw extruder, or a multi-screw extruder. In order to prevent deterioration of the resin, the heating temperature of the extruder is preferably T° C. to (T+70)° C., where T is the melting point of the resin. Further, as described above, by arranging a mesh in the extruder and optimizing the heating temperature, resins other than the target resin can be removed.

[Pelletization process]
FIG. 1 illustrates the a ^* value and b ^* value defined in the CIE 1976 color system for each band color for a new binding band (virgin band). In the new blue cable ties on the market, the hue angle h defined by tan ^-1 (b ^* /a ^* ) is 275° to 285°, and the new blue cable ties have L ^* as shown in FIG. Located in the fourth quadrant of the a ^* b ^* plane.

In addition, among the collected used cable ties, only used blue cable ties were collected.
The average chroma C ^* defined by C* was 24.34, which is significantly lower than the chroma of cut products made of only yellow cable ties. When only used blue cable ties are collected at the laboratory level, the saturation is 24.34, which is slightly higher than 20, so the saturation is 24.34, which is slightly higher than 20, so the saturation is 24.34, which is slightly higher than 20. Therefore, the saturation is 24.34, which is slightly higher than 20. It is not easy to achieve a color saturation of 15 or higher, which is close to the saturation.

Therefore, in the present invention, a blue coloring material composition for a blue recycled resin composition is mixed with the above-mentioned melt-kneaded material (blue recycled base material) to form pellets (blue recycled resin composition).

((Blue coloring material composition for blue recycled resin composition))
As mentioned above, commercially available polypropylene packing ties come in a variety of colors such as blue, yellow, white, transparent, red, green, and black, but blue, yellow, white, or transparent are used the most in that order. . Approximately 60% to 70% of recovered items are recycled as blue. Therefore, the blue colorant composition for the blue recycled resin composition is extremely important.

The form of the blue colorant composition can be selected as appropriate in consideration of handleability and cost, and can be either (1) the colorant itself in powder form, or (2) the colorant solidified to a high concentration using a carrier resin. Examples include masterbatches, (3) granular products in which a coloring material is hardened with wax or the like, and (4) liquid products in which a coloring material is melted in a liquid. The colorant for the blue recycled resin composition contains a first pigment (ulmarine blue pigment), titanium dioxide, and optionally a second pigment (phthalocyanine blue pigment).

Below, as an example, a case where the blue colorant composition is a masterbatch will be described. When the blue colorant composition is a masterbatch, the blue colorant composition contains a carrier resin in addition to the above-mentioned components.

(Carrier resin)
In addition to the masterbatch's original purpose of stably mixing and molding the components contained in the masterbatch, the carrier resin also functions as a resin to adjust the durability of the recycled blue cable tie.

The carrier resin is preferably the same material as the resin contained in the used packaging tie. Therefore, the carrier resin has polyolefin and/or polyethylene terephthalate as a main component. The carrier resin is often made of polyolefin as the main component because it is used relatively frequently for used packaging cable ties and because its melting point is relatively low, the manufacturing cost of the masterbatch can be reduced. preferable. However, when the resin contained in the used packaging binding band is polyethylene terephthalate, it is preferable that the carrier resin has polyethylene terephthalate as a main component.

In this embodiment, the main component means the component with no other components or, if there are other components, the component with the largest amount. The proportion of the main component is 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and preferably 95% by mass or more, based on 100 parts by mass of the carrier resin. It is even more preferable, and particularly preferably 99% by mass or more.

The proportion of carrier resin contained in the masterbatch is not particularly limited. The proportion of carrier resin is determined from the viewpoint of stably mixing and molding each component contained in the masterbatch, and from the viewpoint of making the volume of the masterbatch to a volume that can be uniformly dispersed in the melt-kneaded material (blue recycled base material). The lower limit of is preferably 10 parts by mass or more, more preferably 20 parts by mass or more based on 100 parts by mass of the masterbatch.

In addition, from the viewpoint of preventing the hassle of inventory management due to increased capacity, the upper limit of the proportion of carrier resin is preferably 90 parts by mass or less, more preferably 70 parts by mass or less, based on 100 parts by mass of the masterbatch. It is preferably at most 50 parts by mass, more preferably at most 40 parts by mass.

(First pigment: ultramarine pigment)
The first pigment used in this embodiment is a pigment having a hue angle of 240° to 255° as defined in the CIE1976 color system. In addition, in this embodiment, the first pigment is described as an "ulmarine pigment" for convenience, emphasizing the ease of understanding the content of the invention. However, the first pigment is not limited to an ultramarine pigment, and may have a hue angle All pigments and pigment mixtures are included within the scope of the present invention as long as they are between 240° and 255°.

In the present invention, by containing the ultramarine pigment in the masterbatch, even if the melt-kneaded product (blue reproduction base material) has low chroma and contains black, loss of blue color due to black contamination can be suppressed to a minimum. can.

The proportion of ultramarine pigment contained in the masterbatch is not particularly limited. From the viewpoint of preventing inventory management efforts due to large capacity, the lower limit of the proportion of ultramarine is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and 20 parts by mass or more, based on 100 parts by mass of the masterbatch. It is more preferably at least 30 parts by mass, particularly preferably at least 30 parts by mass.

In addition, from the viewpoint of preventing the inability to stably mix and mold each component contained in the masterbatch due to too small a proportion of the carrier resin, the upper limit of the proportion of ultramarine is set per 100 parts by mass of the masterbatch. It is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, and particularly preferably 60 parts by mass or less.

Blue pigments include not only ultramarine pigments but also ultramarine (hue angle: 234°), azurite (hue angle: 220°), deep blue (Prussian blue, hue angle: 220°), cobalt blue ( Many are known, such as cobalt aluminate, hue angle: 200°), cerulean blue (cobalt stannate, hue angle: 197°), and phthalocyanine blue (hue angle: 275° to 285°). However, all of these complementary colors using blue pigments lose more blue color due to black contamination than complementary colors using ultramarine pigments, and do not lead to improved saturation. Therefore, using only complementary colors using blue pigments other than ultramarine pigments or mixtures of these blue pigments may require a relatively large amount of pigment, which is not preferable.

(titanium dioxide)
Titanium dioxide is also called titanium white. Titanium dioxide has a light-shielding property, and by shielding the black color contained therein, a chromatic resin composition with a different tone can be obtained.

The crystal type of titanium dioxide is not particularly limited and may be any of tetragonal, rutile, anatase, etc., but it has a relatively high refractive index and has a shielding property for the black color contained in it. The crystal type of titanium dioxide is preferably rutile type because of its excellent properties.

The proportion of titanium dioxide contained in the masterbatch is not particularly limited. From the perspective of preventing inventory management efforts due to increased capacity, the lower limit of the proportion of titanium dioxide is preferably 1 part by mass or more, more preferably 2 parts by mass or more, per 100 parts by mass of the masterbatch. More preferably, the amount is 3 parts by mass or more. Further, the lower limit of the proportion of titanium dioxide is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, based on 100 parts by mass of the ultramarine pigment.

In addition, from the viewpoint of preventing the inability to stably mix and mold each component contained in the masterbatch due to the ratio of carrier resin being too small, and from the viewpoint of ensuring sufficient product strength, the ratio of titanium dioxide was adjusted. The upper limit is preferably 45 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 35 parts by mass or less, and 30 parts by mass or less based on 100 parts by mass of the masterbatch. is particularly preferred. Further, the upper limit of the proportion of titanium dioxide is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, based on 100 parts by mass of the ultramarine pigment.

In addition, white pigments include not only titanium dioxide (titanium white), but also zinc oxide (also called zinc white, zinc white), a mixture of barium sulfate and zinc sulfide (lithopone), and basic lead carbonate ( _2PbCO3 . Pb(OH) ₂ , lead white), etc. are also known. However, all of these white pigments are poorer in blocking black color than titanium dioxide. Therefore, if only a complementary color using a white pigment other than titanium dioxide (preferably rutile titanium dioxide) or a mixture of these white pigments is used, the amount of pigment used may be relatively large, and sufficient product strength cannot be ensured. This is not preferable because it may affect manufacturing stability.

(Second pigment: phthalocyanine blue pigment)
Although it is an optional component, in this embodiment, it is preferable that the masterbatch further contains a second pigment (phthalocyanine blue pigment). The second pigment is a pigment having the hue angle of 275° to 285°. Since the masterbatch contains both the first pigment (ulmarine blue pigment) and the second pigment (phthalocyanine blue pigment), a complementary color effect by both of these blue pigments can be obtained, so that the melt-kneaded product (blue recycled base material) The loss of blue color due to black contamination can be further suppressed.

In addition, in this embodiment, the second pigment is described as a "phthalocyanine blue pigment" for convenience, emphasizing the ease of understanding the content of the invention, but the second pigment is not limited to the phthalocyanine blue pigment, and the hue All pigments and pigment mixtures with angles between 275° and 285° are within the scope of the present invention.

The phthalocyanine blue pigment is an optional component, and the proportion of the phthalocyanine blue pigment contained in the masterbatch is not particularly limited, and may not be included. When the masterbatch contains a phthalocyanine blue pigment as an optional component, the lower limit of the proportion of the phthalocyanine blue pigment is 1 part by mass or more per 100 parts by mass of the masterbatch, in order to prevent the hassle of inventory management due to large capacity. The amount is preferably 1.5 parts by mass or more, more preferably 3 parts by mass or more, and particularly preferably 5 parts by mass or more. Further, the lower limit of the proportion of the phthalocyanine blue pigment is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, based on 100 parts by mass of the ultramarine blue pigment.

In addition, from the viewpoint of preventing the inability to stably mix and mold the components contained in the masterbatch due to too small a proportion of the carrier resin, the upper limit of the proportion of the phthalocyanine blue pigment is set at 100 parts by mass of the masterbatch. It is preferably 30 parts by mass or less, more preferably 20 parts by mass or less. Further, the upper limit of the proportion of the phthalocyanine blue pigment is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, based on 100 parts by mass of the ultramarine blue pigment.
stomach.

(other ingredients)
In this embodiment, conventionally known additives such as heat stabilizers, light stabilizers, antistatic agents, lubricants, fillers, copper damage preventive agents, antibacterial agents, colorants, and product strength improvers are used in accordance with the present invention. It can be added within the range that does not impair the effect of. In particular, when a heat stabilizer or a light stabilizer that improves weather resistance is added, the problem of deterioration caused by repeated recycling is alleviated, and the recycled packing band can be used outdoors or for a long period of time.

(Method for manufacturing masterbatch)
A masterbatch is obtained by mixing various components and mixing them using a heating mixer, a heating kneader, an extruder, an extrusion pelletizer, a disc berettor, or the like. The obtained pellet-like or powder-like mixture may be used as it is as a compound for mixing the base resin, or may be further melt-kneaded using an extruder or a pelletizer to form pellets.

For binding, the mixing temperature may be at least the melting point of the carrier resin, but is preferably about 10° C. higher than the melting point.

((Mixing of melt-kneaded material and masterbatch, pelletization))
The method of pelletizing the mixture of the melt-kneaded material and the masterbatch is not limited, and the same method as described in (method for producing masterbatch) can be used.

In addition, although this embodiment is described as pelletizing the mixture of the melt-kneaded material and the masterbatch, the present invention is not limited to this. The first pigment, titanium dioxide, and optionally the second pigment and other additives may be directly mixed into the melt-kneaded material and then pelletized without specifically producing a masterbatch. However, in the present invention, it is preferable to pelletize the mixture of the melt-kneaded material and the masterbatch because there are problems in handling, such as easy scattering, easy to stain equipment, and difficulty in measuring.

[Step of stretching and molding the blue recycled resin composition]
In this embodiment, a band made of a cured product of the recycled resin composition can be manufactured by melt-stretching the obtained recycled resin composition. Melt stretch molding can be performed according to a known method. Furthermore, by subjecting the band to the surface treatment as described above, cutting it to a desired length, and winding it up, it can be made into a binding band for recycled packaging.

<Blue recycled resin composition>
The blue recycled resin composition includes a blue coloring material derived from used packing ties, a first pigment (ulmarine pigment) having a hue angle of 240° to 255°, titanium dioxide, and optionally a hue angle of 275°. and a second pigment (phthalocyanine blue pigment) having an angle of 285°.

The proportion of the first pigment (ulmarine blue pigment) contained in the blue recycled resin composition is 0.5 parts by mass or more and 2 parts by mass or less, and the proportion of titanium dioxide is 0.05 parts by mass or more and less than 0.5 parts by mass. The proportion of the second pigment (phthalocyanine blue pigment) is 0 parts by mass or more and 1 part by mass or less. In particular, the proportion of the first pigment (ulmarine pigment) is 0.5 parts by mass or more, more preferably 1 part by mass or more, and 1.5 parts by mass or more based on 100 parts by mass of the blue reproduction base material. It is even more preferable that there be. When the proportion of the first pigment (ulmarine blue pigment) is 1 part by mass or more, it is possible to have a chroma C ^* of 18 or more regardless of the presence or absence of the second pigment (phthalocyanine blue pigment). Further, by setting the proportion of the second pigment (ulmarine blue pigment) to be 1.5 parts by mass or more, it is possible to provide a chroma C ^* of 20 or more regardless of the presence or absence of the second pigment (phthalocyanine blue pigment).

Saturation C ^* represents the distance from the origin in the L ^* a ^* b ^* color space of the CIE1976 color system, and the larger the value, that is, the farther the distance from the origin, the higher the vividness of the color. The chromatic recycled resin composition of the present invention contains a specific chromatic coloring material and has a chroma C ^* of 15 or more, so it exhibits a vivid chromatic color. The higher the saturation C ^* is, the more preferable it is, preferably 18 or more, and more preferably 20 or more. According to the invention described in this embodiment, whether recycling is done manually or mechanically, high-quality blue recycled resin compositions and packaging materials can be produced using a considerable amount of low-colored pellets of black or other colors as raw materials. We can provide blue recycled cable ties. The upper limit of chroma C ^* is not limited, but is usually 80 or less.

The hue angle h of the blue recycled resin composition is preferably 240° or more, more preferably 250° or more, and even more preferably 255° or more. Further, the hue angle h is preferably 300° or less, more preferably 290° or less, and even more preferably 280° or less. Thereby, the user can visually recognize that the color is the same as that of a new blue packing band. Note that the phase angle h of the new blue packing band is 270° to 280°.

Hue angle h represents the angle with respect to the a * axis in the L ^* a ^* b ^* color space, 0° or positive ^{a * axis} direction is red, 180° or negative a ^* axis direction is green, which is the complementary color of red, 90 ° or plus b ^* axis direction is yellow, 270° or minus b ^* axis direction is blue, which is the complementary color of yellow. A blue reproduction resin composition whose hue angle h, chroma C ^* , and lightness L ^* are within the above ranges provides a highly distinguishable reproduction band.

The blue recycled resin composition of the present invention has PP or PET as a main component. In this embodiment, the main component means the component with no other components or, if there are other components, the component with the largest amount. The proportion of the main component is 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more, based on 100 parts by mass of the resin component contained in the blue recycled resin composition. It is even more preferably 95% by mass or more, and particularly preferably 99% by mass or more.

The recycled blue resin composition of the present invention may be made from used packing ties collected from the market. Recycled resin compositions obtained using materials collected from the market contain impurities such as metals and inorganic substances, but the amount is extremely small and there are a wide variety of types of impurities, so it is difficult to accurately identify them. Moreover, there are circumstances in which it is impractical to quantify it.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

<Cutting used PP packaging cable ties>
A plurality of used PP packaging cable ties of different hues and materials were prepared, and the black cable tie was manually removed from them. Next, the plurality of used PP packaging cable ties were cut to obtain a cutting mixture. The cutting was performed using a uniaxial crusher manufactured by Nippon Seam Co., Ltd. at a throughput of about 10 kg/min. 90% by weight of the cutting mixture ranged in length from 1 cm to 60 cm.

<Color sorting>
The cutting mixture was color sorted using an optical sorter model Mistral+1600 manufactured by Perenc ST. Color selection was performed using color designations based on the spectral characteristics of packing ties registered in advance and standard sensitivity. The conveyor belt speed was 3 m/sec. 1 kg of the cutting mixture was supplied to the apparatus and was sorted into two, a blue mixture and a mixture of other colors, under color specification conditions. However, only when blue cut pieces were detected, air from the lower nozzle was used to transport them to a receiver located far from the conveyor. In order to confirm whether it is possible to reliably provide a blue reproduction band with a saturation of 20 or more, the obtained blue mixture was re-tested in order to use a blue mixture with a relatively high mixing ratio of black, etc. as a test sample. We deliberately did not try to eliminate as much as possible cut pieces other than blue by feeding them into the apparatus under the same conditions.

実施例１：再生混色ペレットに群青顔料１％及び酸化チタンを加えたもの
実施例２：再生混色ペレットに群青顔料１．５％及び酸化チタンを加えたもの
実施例３：再生混色ペレットに群青顔料、酸化チタン及びフタロシアニンブルー顔料を加えたもの
比較例１：再生混色ペレットそのもの
比較例２：再生混色ペレットにフタロシアニンブルー顔料を加えたもの
比較例３：再生混色ペレットに酸化チタン及びフタロシアニンブルー顔料を加えたもの
参考例１：再生混色ペレットにバージン材（青色ＰＰ）、酸化チタン及びフタロシアニンブルー顔料を加えたもの（バージン材１５％）
参考例２：再生混色ペレットにバージン材（青色ＰＰ）、酸化チタン及びフタロシアニンブルー顔料を加えたもの（バージン材３０％） <Manufacture of blue recycled resin composition (pellets)>
First, the blue mixture was melt-kneaded using an extruder to obtain recycled mixed color pellets. Then, the raw materials listed in Table 1 were kneaded using an extruder to obtain blue recycled resin compositions (pellets) according to Examples, Comparative Examples, and Reference Examples. In Table 1, the virgin material (PP) is a commercially available uncolored polypropylene pellet.

Example 1: 1% ultramarine pigment and titanium oxide added to recycled mixed color pellets Example 2: 1.5% ultramarine pigment and titanium oxide added to recycled mixed color pellets Example 3: Ultramarine blue pigment added to recycled mixed color pellets , titanium oxide and phthalocyanine blue pigment are added Comparative Example 1: Regenerated mixed color pellet itself Comparative Example 2: Phthalocyanine blue pigment is added to the recycled mixed color pellet Comparative Example 3: Titanium oxide and phthalocyanine blue pigment are added to the recycled mixed color pellet Reference example 1: Regenerated mixed color pellets with virgin material (blue PP), titanium oxide and phthalocyanine blue pigment added (virgin material 15%)
Reference example 2: Virgin material (blue PP), titanium oxide, and phthalocyanine blue pigment added to recycled mixed color pellets (30% virgin material)

<Color characteristic evaluation>
Each sample according to the example, comparative example, and reference example was melted using a heat press machine set at 210° C. and then cooled to prepare a resin plate with a thickness of 2 mm. Using a colorimeter/color difference meter ZE-2000 manufactured by Nippon Denshoku Industries Co., Ltd., measure the L ^* value, a ^* value, and b ^* value of the resin plate, and then calculate the chroma C ^* (C ^*) from the measured values. =(a ^*2 +b ^*2 ) ^1/2 ) and the hue angle h(=tan ^-1 (b ^* /a ^* )).The results are shown in Table 2.

The blue recycled resin composition of the example has a chroma C ^* that is comparable to the blue recycled resin compositions of Reference Examples 1 and 2, which were complemented with virgin material (blue PP). In addition, the hue angle h is 256.42° to 260.73°, which is equivalent to that of the blue recycled resin composition of Reference Example 2, and the hue angle h (270° to 280°) of a new blue packing band. °) close to The ability to provide a blue recycled resin composition that exhibits a blue color close to that of a new cable tie without using a complementary color with virgin material (blue PP) can be said to be an extremely remarkable effect that exceeds the range that could be predicted from the conventional technology.

On the other hand, Comparative Example 1 (the recycled mixed color pellet itself) had a chroma C ^* of only 6.20. It is obvious even by visual inspection that the recovered blue products contain yellow, black, etc., and cannot be supplied as recycled blue cable ties as is.

Comparative Example 2 (complementary color with phthalocyanine blue pigment) also had a chroma C ^* of only 12.520, far from 15 or higher. This confirms that the chroma of mixed color pellets is low, especially when manually sorted, and that it was virtually impossible to provide a blue recycled resin composition with a chroma of 15 or more using conventional technology. .

Comparative Example 3 (complementary color with phthalocyanine blue pigment and titanium dioxide) shows an improvement in chroma C ^* , but compared to Comparative Example 2, the hue angle h moves from 259.65 to 240.554. There is. This is a movement away from the hue angle h (270° to 280°) of the new blue packing band, and the user may perceive that the color is different from the new one.

Both Reference Examples 1 and 2 have a quality that can be supplied as recycled blue cable ties, but this is due to the complementary coloring of virgin material (blue PP). From the viewpoint of greenhouse gas reduction, it is preferable to reduce the amount of virgin material used, and from this viewpoint, the present invention is superior to Reference Examples 1 and 2. For example, the total annual demand for PP packing ties in Japan is approximately 36,000 tons. Assuming that 30% of used products are collected and 80% of them are recycled, the method of Reference Example 2 can reduce virgin materials by approximately 3,700 tons (= 36,000 x 30% x 80% x 3/7) per year. . The CO ₂ reduction effect at this time is estimated to be approximately 5,700 tons when calculated based on the reference values listed in Table 3.
3700×(1.49+0.033+0.016)=5,694.3(t)

Furthermore, assuming that all of this collected waste had been previously incinerated, the amount of CO ₂ reduced would increase by 11,000 tons, so a total CO ₂ reduction effect of 16,000 tons per year can be expected.
3700×3.14=11,618(t)

The energy consumption of the recycling equipment used to regenerate PP is only the amount of electricity used to operate the equipment, and when estimated from the estimated amount of electricity, the CO ₂ emissions during regeneration will be 640 tons, which is a total CO ₂ reduction of 16,000 tons per year. The effect is slight on

Among the recycled PP bands manufactured by horizontal recycling of used PP bands collected from the market, we manufacture and supply products with a blue color saturation of 20° or more that can be described as blue among the blue-colored recycled PP bands that have the highest demand. was difficult. In particular, when manually sorting, it was thought that this was practically impossible, but the present invention overcomes this problem at once, and makes it possible to produce blue color even with a considerable amount of black or mixed pellets of other colors.

Furthermore, the present invention allows a high-level horizontal recycling system to be constructed. As a result, it is possible to significantly reduce the amount of virgin bands used and the amount of incineration of used packing ties, thereby making it possible to achieve a significant reduction in carbon dioxide, which is a greenhouse gas. Furthermore, the present invention is expected to significantly reduce the number of discarded packing ties, including illegally dumped ones, making it possible to reduce microplastics, which are one of the causes of ocean pollution.

Therefore, the industrial applicability of the present invention is considered to be extremely large.

Claims (7)

a first pigment having a hue angle defined in the CIE 1976 color system of 240° to 255°;
Contains titanium dioxide,
A blue colorant composition for a blue recycled resin composition, wherein the content of titanium dioxide is 10 parts by mass or more and less than 50 parts by mass with respect to 100 parts by mass of the first pigment. further comprising a second pigment having the hue angle of 275° to 285°,
The coloring material composition according to claim 1, wherein the content of the second pigment with respect to 100 parts by mass of the first pigment is 15 parts by mass or more and 30 parts by mass or less. A blue recycled base material whose main component is polyolefin and/or polyethylene terephthalate and whose hue angle is 240° to 300°, which is obtained by recycling a plurality of used packaging cable ties with different hues and materials;
The coloring material composition according to claim 1;
Contains
The proportion of the coloring material composition is 0.5 parts by mass or more and 2 parts by mass or less with respect to a total of 100 parts by mass of the blue recycled base material and the carrier resin contained as an optional component in the coloring material composition,
A blue reproduction resin composition having a chroma C ^* of 15 or more in the CIE1976 color system when spectral reflection characteristics are measured as a resin plate with a film thickness of 2 mm. A blue color whose main component is polyolefin and/or polyethylene terephthalate, obtained by recycling multiple used packaging cable ties with different hues and materials, and whose hue angle is defined in the CIE 1976 color system from 240° to 300°. recycled base material,
a first pigment having the hue angle of 240° to 255°;
Contains titanium dioxide,
For 100 parts by mass of the blue recycled base material,
The proportion of the first pigment is 0.5 parts by mass or more and 2 parts by mass or less,
A blue recycled resin composition in which the proportion of titanium dioxide is 0.05 parts by mass or more and less than 0.5 parts by mass. A recycled blue binding band for packaging comprising a cured product of the recycled blue resin composition according to claim 3 or 4. Obtained through a color sorting step of preparing a blue mixture by classifying a plurality of used packaging cable ties having different hues and/or materials into blue groups, and a processing step of melting and kneading and/or making the blue mixture into a glaze. A step of mixing the coloring material composition according to claim 1 or 2 with the blue recycled base material to obtain a blue recycled resin composition;
Stretch-molding the blue recycled resin composition to obtain a blue recycled binding band for packaging,
The ratio of the coloring material composition to a total of 100 parts by mass of the blue recycled base material and the carrier resin contained as an optional component in the coloring material composition is 1 part by mass or more and 2 parts by mass or less,
A method for manufacturing a blue recycled cable tie for packaging, wherein the blue recycled cable cable for packaging has a chroma C ^* of 15 or more in the CIE1976 color system when the spectral reflection characteristics are measured as a resin plate with a film thickness of 2 mm. Obtained through a color sorting step of preparing a blue mixture by classifying a plurality of used packaging cable ties having different hues and/or materials into blue groups, and a processing step of melting and kneading and/or making the blue mixture into a glaze. A first pigment having a hue angle defined in the CIE 1976 color system of 240° to 255°, titanium dioxide, and optionally a second pigment having a hue angle of 275° to 285° for the blue reproduction base material. and a step of obtaining a blue recycled resin composition;
Stretch-molding the blue recycled resin composition to obtain a blue recycled binding band for packaging,
For 100 parts by mass of the blue recycled base material,
The proportion of the first pigment is 0.5 parts by mass or more and 2 parts by mass or less,
The proportion of the titanium dioxide is 0.05 parts by mass or more and less than 0.5 parts by mass,
The proportion of the second pigment is 0 parts by mass or more and 0.6 parts by mass or less,
A method for manufacturing a blue recycled cable tie for packaging, wherein the blue recycled cable cable for packaging has a chroma C ^* of 15 or more in the CIE1976 color system when the spectral reflection characteristics are measured as a resin plate with a film thickness of 2 mm.