Resin product manufacturing system and resin product manufacturing method

Abstract

The present invention provides a resin product manufacturing system and a resin product manufacturing method that can stabilize the quality of resin products. [Solution] The resin product manufacturing system 1 comprises a resin supply device 2 that supplies resin flakes F, a decontamination device 3 that decontaminates the resin flakes F supplied from the resin supply device 2 to produce molten resin R, an intrinsic viscosity measuring device 4 that measures the intrinsic viscosity of the molten resin R decontaminated by the decontamination device 3, an injection molding device 30 that injects the molten resin R, and a control device 50 that controls at least one of the decontamination conditions of the decontamination device 3 and the molding conditions of the injection molding device 30 based on the measured intrinsic viscosity.

Description

Technical Field

[0004] ,

[0006] , , , ,

[0005] , , , , , ,

[0001] The present disclosure relates to a resin product manufacturing system and a method for manufacturing a resin product.

Background Art

[0002] Recently, resin containers have become common as containers for storing contents such as food and beverages. Resin containers are manufactured by a biaxial stretch blow molding method in which a preform is inserted into a mold and biaxial stretch blow is applied to the preform. Further, the preform is manufactured by, for example, an injection molding method (see, for example, Patent Document 1). Furthermore, it is known that by providing a pressure sensor in the mold of an injection molding device, detection of appearance defects of a molded product to be judged as good or bad can be assisted (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in resin containers, not only suppressing molding defects and appearance defects, but also suppressing discoloration of the containers, it is also required to stabilize the quality of the containers.

[0005] The present disclosure has been made in consideration of such points, and an object thereof is to provide a resin product manufacturing system and a method for manufacturing a resin product capable of stabilizing the quality of resin products.

Means for Solving the Problems

[0006] Embodiments of the present disclosure relate to the following [1] to

[12] .

[0007] [1] In a resin product manufacturing system for producing resin products from resin flakes, A resin supply device that supplies the aforementioned resin flakes, A decontamination device for producing molten resin by decontaminating the resin flakes supplied from the resin supply device, An intrinsic viscosity measuring device for measuring the intrinsic viscosity of the molten resin that has been decontaminated by the decontamination device, An injection molding apparatus for injection molding the molten resin, A resin product manufacturing system comprising a control device that controls at least one of the decontamination conditions of the decontamination device and the molding conditions of the injection molding device based on the measured intrinsic viscosity.

[0008] [2] If the intrinsic viscosity is higher than a predetermined value, the control device lowers the processing temperature of the decontamination apparatus, increases the pressure inside the decontamination apparatus, or shortens the processing time of the decontamination apparatus. The resin product manufacturing system according to [1], wherein if the intrinsic viscosity is lower than a predetermined value, the control device increases the processing temperature of the decontamination apparatus, decreases the pressure inside the decontamination apparatus, or increases the processing time of the decontamination apparatus.

[0009] [3] If the intrinsic viscosity is higher than a predetermined value, the control device increases the resin temperature in the injection molding apparatus, increases the holding pressure, or lengthens the holding pressure time. If the intrinsic viscosity is lower than a predetermined value, the control device lowers the resin temperature in the injection molding apparatus, lowers the holding pressure, or shortens the holding pressure time, according to the resin product manufacturing system of [1] or [2].

[0010] [4] The system further includes a color measuring device for measuring the color of the molten resin that has been decontaminated by the decontamination device, The resin product manufacturing system according to any one of [1] to [3], wherein the control device controls at least one of the decontamination conditions of the decontamination device and the molding conditions of the injection molding device based on the measured intrinsic viscosity and color.

[0011] [5] The resin product manufacturing system according to [4], wherein the color measurement value measured by the color measuring device is the b value of the CIE-Lab color system, and if the b value is higher than a predetermined value, the control device lowers the processing temperature of the decontamination device, increases the pressure inside the decontamination device, or shortens the processing time of the decontamination device.

[0012] [6] The color measurement value measured by the color measuring device is the b value of the CIE-Lab color system, and if the b value is higher than a predetermined value, the control device lowers the resin temperature in the injection molding apparatus. The resin product manufacturing system according to [4] or [5].

[0013] [7] In a resin product manufacturing system for producing resin products from resin flakes, A resin supply device that supplies the aforementioned resin flakes, A decontamination device for producing molten resin by decontaminating the resin flakes supplied from the resin supply device, A color measuring device for measuring the color of the molten resin that has been decontaminated by the decontamination device, An injection molding apparatus for injecting the molten resin, A resin product manufacturing system comprising a control device that controls at least one of the decontamination conditions of the decontamination device and the molding conditions of the injection molding device based on the measured color.

[0014] [8] The resin product manufacturing system according to [7], wherein the color measurement value measured by the color measuring device is the b value of the CIE-Lab color system, and if the b value is higher than a predetermined value, the control device lowers the processing temperature of the decontamination device, increases the pressure inside the decontamination device, or shortens the processing time of the decontamination device.

[0015] [9] The measured value of the color measured by the color measuring device is the b value in the CIE-Lab color system. When the b value is higher than a predetermined value, the control device increases the holding pressure while decreasing the resin temperature in the injection molding device. The resin product manufacturing system according to [7] or [8].

[0016]

[10] A step of supplying resin flakes to a decontamination device; A step of producing decontaminated molten resin by heating the resin flakes supplied to the decontamination device with the decontamination device; A step of measuring the intrinsic viscosity of the molten resin decontaminated by the decontamination device; A step of molding a resin product with an injection molding device using the molten resin decontaminated by the decontamination device; A step of controlling at least one of the decontamination device and the injection molding device by a control device, In the step of controlling at least one of the decontamination device and the injection molding device, the control device controls at least one of the decontamination conditions of the decontamination device and the molding conditions of the injection molding device based on the measured intrinsic viscosity. A method for manufacturing a resin product.

[0017]

[11] Further comprising a step of measuring the color of the molten resin decontaminated by the decontamination device; In the step of controlling at least one of the decontamination device and the injection molding device, the control device controls at least one of the decontamination conditions of the decontamination device and the molding conditions of the injection molding device based on the measured intrinsic viscosity and the color. The method for manufacturing a resin product according to

[10] .

[0018]

[12] A step of supplying resin flakes to a decontamination device; A step of producing decontaminated molten resin by heating the resin flakes supplied to the decontamination device with the decontamination device; A step of measuring the color of the molten resin that has been decontaminated by the decontamination device, A step of molding a resin product using an injection molding machine with the molten resin that has been decontaminated by the decontamination device, The process includes controlling at least one of the decontamination apparatus and the injection molding apparatus using a control device, A method for manufacturing a resin product, comprising the step of controlling at least one of the decontamination apparatus and the injection molding apparatus, wherein the control device controls at least one of the decontamination conditions of the decontamination apparatus and the molding conditions of the injection molding apparatus based on the measured color. [Effects of the Invention]

[0019] According to this disclosure, it is possible to stabilize the quality of resin products. [Brief explanation of the drawing]

[0020] [Figure 1] Figure 1 is a front view showing a resin product manufactured by a resin product manufacturing system according to one embodiment. [Figure 2] Figure 2 is a schematic diagram showing a resin product manufacturing system according to one embodiment. [Figure 3] Figure 3 is a cross-sectional view showing an injection molding apparatus for a resin product manufacturing system according to one embodiment. [Figure 4] Figure 4 shows a control method for a resin product manufacturing system according to one embodiment. [Figure 5] Figure 5 shows a control method for a resin product manufacturing system according to one embodiment. [Figure 6] Figure 6 shows a control method for a resin product manufacturing system according to one embodiment. [Figure 7] Figure 7 shows a control method for a resin product manufacturing system according to one embodiment. [Figure 8] Figure 8 shows a control method for a resin product manufacturing system according to one embodiment. [Figure 9]Figure 9 is a flowchart showing a method for manufacturing a resin product according to one embodiment. [Figure 10] Figure 10 is a schematic diagram showing a modified example of a resin product manufacturing system according to one embodiment. [Figure 11] Figure 11 is a flowchart showing a modified example of a method for manufacturing a resin product according to one embodiment. [Figure 12] Figure 12 is a schematic diagram showing a modified example of a resin product manufacturing system according to one embodiment. [Figure 13] Figure 13 is a flowchart showing a modified example of a method for manufacturing a resin product according to one embodiment. [Modes for carrying out the invention]

[0021] Hereinafter, an embodiment of this disclosure will be described with reference to the drawings. Figures 1 to 9 are diagrams illustrating one embodiment. The following figures are schematic representations. Therefore, the size and shape of each part are exaggerated as appropriate to facilitate understanding. Furthermore, it is possible to implement the invention with appropriate modifications without departing from the technical concept. In the following figures, the same parts are denoted by the same reference numerals, and some detailed explanations may be omitted. In addition, the numerical values ​​such as dimensions and material names of each component described in this specification are examples of embodiments and are not limited thereto; they can be selected and used as appropriate. In this specification, terms that specify shapes and geometric conditions, such as parallel, orthogonal, and perpendicular, are used not only in their strict sense but also to include substantially the same conditions.

[0022] First, the resin products manufactured by the resin product manufacturing system described herein will be explained. The resin products may be, for example, preforms used to manufacture plastic bottles. Although an example of a resin product being a preform will be explained, the resin products are not limited to such preforms, and any molded articles such as containers manufactured by injection molding, injection compression molding, compression molding, or direct blow molding may be used as resin products.

[0023] As shown in Figure 1, the preform 100 comprises a mouth portion 101, a body portion 102, and a bottom portion 103.

[0024] Of these, the outer circumference of the mouth portion 101 is provided with a threaded portion 104 for screwing on a cap (not shown) after a plastic bottle (not shown) is manufactured by biaxial stretch blow molding of the preform 100. In addition, an annular support ring 105 is provided protruding from the lower part of the mouth portion 101.

[0025] The body portion 102 has a cylindrical shape. The body portion 102 may also have a cylindrical shape that gradually decreases in diameter from the mouth portion 101 side to the bottom portion 103 side. The bottom portion 103 has a roughly hemispherical shape.

[0026] Such a preform 100 can be manufactured, for example, by injection molding a synthetic resin material.

[0027] Resin product manufacturing system Next, the resin product manufacturing system according to this embodiment will be described with reference to Figures 2 and 3. The resin product manufacturing system according to this embodiment is a system for manufacturing resin products from resin flakes. In this disclosure, "recycled resin" means resin that has undergone recycling treatment. Also, "virgin resin" means resin that has not undergone recycling treatment, i.e., unused resin.

[0028] As shown in Figure 2, the resin product manufacturing system 1 comprises a resin supply device 2, a decontamination device 3, an intrinsic viscosity measuring device 4, an injection molding device 30, and a control device 50. The resin product manufacturing system 1 may also further include a color measuring device 5. In the illustrated example, the resin supply device 2, decontamination device 3, intrinsic viscosity measuring device 4, color measuring device 5, and injection molding device 30 are arranged in this order from upstream to downstream. Although not shown in the illustration, the color measuring device 5 may be located upstream of the intrinsic viscosity measuring device 4. Furthermore, the intrinsic viscosity measuring device 4 and the color measuring device 5 may be located inside the decontamination device 3 or inside the injection molding device 30.

[0029] Of these, the resin supply device 2 is a device that supplies resin flakes F to the decontamination device 3. The decontamination device 3 is a device that decontaminates the resin flakes F supplied from the resin supply device 2 to produce molten resin R. The intrinsic viscosity measuring device 4 is a device that measures the intrinsic viscosity of the molten resin R that has been decontaminated by the decontamination device 3. The color measuring device 5 is a device that measures the color of the molten resin R that has been decontaminated by the decontamination device 3. The injection molding device 30 is a device that injection molds resin products by injecting the molten resin R. The control device 50 is a device that controls at least one of the decontamination conditions of the decontamination device 3 and the molding conditions of the injection molding device 30 based on the measured intrinsic viscosity. The control device 50 is also a device that controls at least one of the decontamination conditions of the decontamination device 3 and the molding conditions of the injection molding device 30 based on the measured color.

[0030] The resin supply device 2 is connected to the control device 50 and is configured to be controlled by the control device 50. The resin supply device 2 also contains resin flakes F made from recycled resin. These resin flakes F are made by sorting, crushing, and washing used plastic products. The used plastic products may be, for example, polyester containers. In other words, the resin flakes F may be made from recycled polyester. Such resin flakes F are small pieces of resin, and may be, for example, between 5 mm square and 15 mm square in size.

[0031] In this embodiment, the recycled resin may have a predetermined yellowish tint. Hereafter, "discoloration" will be explained as a change in the color of the resin product relative to a resin product made of virgin resin.

[0032] Furthermore, in this disclosure, "polyester" means a copolymer of a dicarboxylic acid compound and a diol compound.

[0033] Examples of dicarboxylic acid compounds include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedionic acid, eicosanedionic acid, pimelic acid, azelaic acid, methylmalonic acid and ethylmalonic acid, adamantanedicarboxylic acid, norbornenedicarboxylic acid, cyclohexanedicarboxylic acid, decalindicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 5-sodium sulfisoisophthalic acid, phenylendanedicarboxylic acid, anthracenedicarboxylic acid, phenantradicarboxylic acid, 9,9'-bis(4-carboxyphenyl)fluorenic acid and their ester derivatives.

[0034] Examples of diol compounds include ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol, cyclohexanediethanol, decahydronaphthalenedimethanol, decahydronaphthalenediethanol, norbornanediethanol, norbornanediethanol, tricyclodecanedimethanol, tricyclodecaneethanol, tetracyclododecanedimethanol, tetracyclododecaneethanol, decalindiethanol, decalindiethanol, Examples include 5-methylol-5-ethyl-2-(1,1-dimethyl-2-hydroxyethyl)-1,3-dioxane, cyclohexanediol, bicyclohexyl-4,4'-diol, 2,2-bis(4-hydroxycyclohexylpropane), 2,2-bis(4-(2-hydroxyethoxy)cyclohexyl)propane, cyclopentanediol, 3-methyl-1,2-cyclopentadiol, 4-cyclopentene-1,3-diol, adamandiol, paraxylene glycol, bisphenol A, bisphenol S, styrene glycol, trimethylolpropane, and pentaerythritol.

[0035] Among polyesters, polyethylene terephthalate (hereinafter also referred to as PET), which is a copolymer of terephthalic acid and ethylene glycol, or modified polyethylene terephthalate to which copolymer monomers have been added, is preferred.

[0036] The polyester may contain monomers other than dicarboxylic acid compounds and diol compounds, but the content of these monomers is preferably 10 mol% or less, more preferably 5 mol% or less, and even more preferably 3 mol% or less, relative to the total constituent units.

[0037] Next, the decontamination device 3 will be described. The decontamination device 3 plays the role of removing contaminants from the resin flakes F by heating them under reduced pressure and causing them to volatilize. The decontamination device 3 also plays the role of producing decontaminated molten resin R by melting the resin flakes F. The decontamination device 3 is connected to the control device 50 and is configured to be controlled by the control device 50.

[0038] The decontamination device 3 is connected to an exhaust passage (not shown) for reducing the pressure inside the device. This exhaust passage is connected to a vacuum pump (not shown), and by driving the vacuum pump, the pressure inside the decontamination device 3 is reduced. During decontamination, the pressure inside the decontamination device 3 may be, for example, 50 Pa or more and 500 Pa or less. By having a pressure inside the decontamination device 3 of 50 Pa or more, it is possible to suppress the intrinsic viscosity of the molten resin R from becoming too high. Also, by having a pressure inside the decontamination device 3 of 50 Pa or more, it is possible to suppress the b value, which will be described later, from becoming too high. Furthermore, by having a pressure inside the decontamination device 3 of 500 Pa or less, contaminants can be removed more effectively from the resin flakes F, and the intrinsic viscosity of the molten resin R can be suppressed from becoming too low.

[0039] Furthermore, a heating mechanism (not shown) is provided inside the decontamination device 3. The heating mechanism heats the resin flakes F supplied into the decontamination device 3, causing the contaminants to volatilize. Also, during decontamination, the temperature inside the decontamination device 3 (the processing temperature of the decontamination device 3) may be, for example, between 180°C and 290°C. A temperature of 180°C or higher inside the decontamination device 3 allows for more effective removal of contaminants from the resin flakes F and prevents the intrinsic viscosity of the molten resin R from becoming too low. A temperature of 290°C or lower inside the decontamination device 3 prevents the intrinsic viscosity of the molten resin R from becoming too high. Furthermore, a temperature of 290°C or lower inside the decontamination device 3 prevents the b value, which will be described later, from becoming too high. In addition, nitrogen may be injected into the decontamination device 3 during decontamination. Injecting nitrogen into the decontamination device 3 reduces the oxidation of the resin flakes F inside the device 3, thereby reducing yellowing of the resin product. Although not shown in the diagram, the decontamination apparatus 3 may also be equipped with a drying chamber for drying the resin flakes F while removing dust and other foreign matter from the resin flakes F before heating the resin flakes F.

[0040] Furthermore, the decontamination time in the decontamination device 3 (processing time of the decontamination device 3) may be, for example, 20 minutes or more and 120 minutes or less. By setting the decontamination time in the decontamination device 3 to 20 minutes or more, it is possible to prevent the intrinsic viscosity of the molten resin R from becoming too low. Also, by setting the decontamination time in the decontamination device 3 to 120 minutes or less, it is possible to prevent the intrinsic viscosity of the molten resin R from becoming too high. Also, by setting the decontamination time in the decontamination device 3 to 120 minutes or less, it is possible to prevent the b value, which will be described later, from becoming too high.

[0041] Furthermore, the decontamination device 3 also plays a role in increasing the intrinsic viscosity (expressed as the IV value in the case of PET resin) of the molten resin R from which contaminants have been removed. In this case, for example, if the resin flakes F are PET flakes, the IV value of the molten resin R may be increased in the decontamination device 3 to approximately 0.72 dL / g or more and 0.88 dL / g or less. The IV value is measured in the intrinsic viscosity measuring device 4 using a measurement method compliant with the conditions of JIS K 7390:2003.

[0042] Furthermore, the decontamination device 3 is equipped with a dispensing device (not shown), such as a screw or gear pump, for sending the molten resin R downstream. The dispensing device then pushes the molten resin R downstream of the decontamination device 3.

[0043] Next, the intrinsic viscosity measuring device 4 will be described. The intrinsic viscosity measuring device 4 is a device that acquires information regarding the intrinsic viscosity (IV value) of the molten resin R. The intrinsic viscosity measuring device 4 measures the intrinsic viscosity according to a measurement method that conforms to the conditions of JIS K 7390:2003. Such an intrinsic viscosity measuring device 4 is connected to a control device 50, and is configured to transmit the measured value of the intrinsic viscosity of the molten resin R (i.e., information regarding the intrinsic viscosity of the molten resin R) as a signal to the control device 50. Note that the measured value of the intrinsic viscosity of the molten resin R may be, for example, the average value of multiple measured values, or for example, the average value of 50 measured values.

[0044] Next, the color measuring device 5 will be described. In this embodiment, the color measuring device 5 includes a colorimeter. This colorimeter is a device that acquires information about the color of the molten resin R by observing the molten resin R. The size and / or shape of the area in which the colorimeter acquires information about the color of the molten resin R is not particularly limited, as long as the area is within the molten resin R. For example, the colorimeter may acquire information about the color of the molten resin R from any area of ​​about 10 mm square in the molten resin R. Such a color measuring device 5 is connected to a control device 50, and is configured to transmit the measured value of the color of the molten resin R (i.e., information about the color of the molten resin R) to the control device 50 as a signal. The measured value of the color of the molten resin R may be, for example, the average value of multiple measured values, or for example, the average value of 50 measured values.

[0045] In this embodiment, the color measuring device 5 may also measure at least the b value of the molten resin R in the CIE-Lab color system. This allows for effective inspection of yellowing that has occurred in the molten resin R.

[0046] Furthermore, if the resin flakes F are made from recycled polyester containing a bluing agent, the b-value of the molten resin R may be between -10 and -2. If the resin flakes F are made from recycled polyester without a bluing agent, the b-value of the molten resin R may be between +3 and +5. The b-value of pellets made from virgin polyester is approximately between -1 and +2.

[0047] Next, the injection molding apparatus 30 will be described. This injection molding apparatus 30 is a device that injection molds resin products using molten resin R. The injection molding apparatus 30 is connected to a control device 50 and is configured to be controlled by the control device 50.

[0048] As shown in Figure 3, the injection molding apparatus 30 includes a barrel 31 into which molten resin R is supplied, a conveying screw 32 provided inside the barrel 31 to send the molten resin R downstream, a storage section 33 for storing the molten resin R sent by the conveying screw 32, and a nozzle 34 for injecting the molten resin R stored in the storage section 33.

[0049] A heating heater 35 is positioned around the outer circumference of the barrel 31 to heat the barrel 31. This allows the temperature of the molten resin R supplied into the barrel 31 (resin temperature) to be adjusted. A first channel 36 is also connected to the barrel 31 for transporting the molten resin R, which has been sent by the conveying screw 32, to the downstream side.

[0050] The conveying screw 32 rotates to transport the molten resin R to the first flow path 36. This conveying screw 32 is equipped with spirally circulating flights 32a. These flights 32a transport the molten resin R to the first flow path 36.

[0051] The storage unit 33 includes a cylinder 33a for storing molten resin R conveyed by the conveying screw 32, and a plunger 33b for pushing out the molten resin R stored in the cylinder 33a. The plunger 33b is configured to slide forward within the cylinder 33a by a drive mechanism 33c, and to slide backward within the cylinder 33a by the pressure of the molten resin R. When the plunger 33b is retracted relative to the cylinder 33a, the molten resin R is stored and metered within the cylinder 33a. On the other hand, when the plunger 33b is advanced relative to the cylinder 33a, the molten resin R is injected from the nozzle 34 into the injection molding die (mold 40, described later).

[0052] Furthermore, a second channel 37 is connected to the storage section 33 for transporting the molten resin R conveyed by the first channel 36 to the storage section 33, and for supplying the molten resin R stored in the storage section 33 to the nozzle 34. The first channel 36 is connected to the second channel 37. A three-way valve 38 is provided between the first channel 36 and the second channel 37 to prevent backflow of the molten resin R stored in the storage section 33, and to prevent the molten resin R from being supplied to the nozzle 34 when the molten resin R is stored in the storage section 33. When the molten resin R supplied into the barrel 31 is sent to the storage section 33, the three-way valve 38 is opened so that the first channel 36 and the second channel 37 communicate with each other. In this case, the first channel 36 does not communicate with the nozzle 34. On the other hand, when injecting the molten resin R stored in the storage section 33 into the cavity 41 of the mold 40 (described later), the three-way valve 38 is opened so that the second passage 37 and the nozzle 34 communicate with each other. In this case, the second passage 37 does not communicate with the first passage 36. In this way, when sending the molten resin R to the storage section 33, it is possible to prevent the molten resin R from being supplied to the nozzle 34, and when injecting the molten resin R from the nozzle 34, it is possible to prevent the molten resin R from flowing back into the barrel 31.

[0053] Furthermore, as shown in Figure 3, the injection molding apparatus 30 may further include a mold 40, a fixed platen 44a that holds the mold 40, and a movable platen (not shown). The mold 40 held by the fixed platen 44a and the movable platen has a cavity 41 that is filled with molten resin R injected from the storage section 33. Specifically, the mold 40 includes a cavity-side mold 42 and a core 43. The cavity-side mold 42 is attached to the fixed platen 44a. The movable platen (not shown) is located on the opposite side of the mold 40 from the fixed platen 44a, and the movable platen is further attached to a clamping device (not shown). The mold 40 is configured such that a cavity 41 corresponding to the shape of the resin product to be manufactured is formed by clamping the cavity-side mold 42 and the core 43 using the clamping device. The clamping device described above may be, for example, a direct pressure type or a toggle type.

[0054] In molding resin products, molten resin R is injected from the nozzle 34 into the mold 40, and then a holding pressure is applied to the molten resin R by the plunger 33b. The holding pressure applied to the molten resin R may be a constant pressure, or multiple pressures may be applied in stages, and the maximum value may be between 30 MPa and 80 MPa. By setting the holding pressure to 30 MPa or higher, defects such as short shots and sink marks can be prevented from occurring in the resin product. Furthermore, by setting the holding pressure to 80 MPa or lower, the generation of burrs in the resin product can be suppressed.

[0055] Furthermore, the holding pressure time may be, for example, between 2 seconds and 10 seconds. Holding pressure for 2 seconds or more can suppress the weight of the resin product from becoming lighter than the designed weight (smaller dimensions) and the occurrence of sink marks. Holding pressure for 10 seconds or less can suppress the weight of the resin product from becoming heavier than the designed weight (larger dimensions) and the occurrence of burrs on the resin product.

[0056] Next, the control device 50 will be described. As mentioned above, the control device 50 controls at least one of the decontamination conditions of the decontamination device 3 and the molding conditions of the injection molding device 30 based on the measured intrinsic viscosity and color. Here, when the resin product (preform 100) is injection molded, if the intrinsic viscosity (IV value) of the molten resin R increases, the fluidity of the molten resin R decreases. This can result in the resin product being lighter (smaller in dimensions) than its designed weight. On the other hand, if the intrinsic viscosity of the molten resin R decreases, the fluidity of the molten resin R increases. This can result in the resin product being heavier (larger in dimensions) than its designed weight. Also, if the intrinsic viscosity of the molten resin R decreases, burrs may form on the resin product. Furthermore, if the b value of the molten resin R increases, the injection-molded resin product (preform 100) may have a yellowish tint. For this reason, generally, in order to improve the quality of the resin product and stabilize its quality, the operator controls at least one of the decontamination conditions of the decontamination device and the molding conditions of the injection molding device. Here, the decontamination conditions for the decontamination equipment include the processing temperature of the decontamination equipment, the pressure inside the decontamination equipment, or the processing time of the decontamination equipment. In addition, the molding conditions for the injection molding equipment include the holding pressure, the holding pressure time, and the resin temperature.

[0057] In this embodiment, if the intrinsic viscosity of the molten resin R is higher than a predetermined value, the control device 50 may lower the processing temperature of the decontamination device 3, increase the pressure inside the decontamination device 3, or shorten the processing time of the decontamination device 3. This can lower the intrinsic viscosity of the molten resin R. The control device 50 may also control the decontamination conditions of the decontamination device 3 when the IV value, which is the intrinsic viscosity of the molten resin R, is 0.005 dL / g or more above the target value, or when the IV value, which is the intrinsic viscosity of the molten resin R, is 0.01 dL / g or more above the target value.

[0058] On the other hand, if the intrinsic viscosity is lower than a predetermined value, the control device 50 may increase the processing temperature of the decontamination device 3, decrease the pressure inside the decontamination device 3, or increase the processing time of the decontamination device 3. This can increase the intrinsic viscosity of the molten resin R. The control device 50 may also control the decontamination conditions of the decontamination device 3 when the IV value, which is the intrinsic viscosity of the molten resin R, falls below 0.005 dL / g from the target value, or when the IV value, which is the intrinsic viscosity of the molten resin R, falls below 0.01 dL / g from the target value.

[0059] Furthermore, if the intrinsic viscosity of the molten resin R is higher than a predetermined value, the control device 50 may increase the holding pressure of the injection molding apparatus 30, increase the holding pressure time, or increase the temperature of the molten resin R (resin temperature). This allows the resin product to be maintained at the target weight and dimensions by adjusting at least one of the holding pressure and holding pressure time, even when the intrinsic viscosity of the molten resin R is high, and the fluidity of the molten resin R can be increased by adjusting the resin temperature. The control device 50 may also control the molding conditions of the injection molding apparatus 30 when the intrinsic viscosity of the molten resin R is 0.005 dL / g or more above the target value, or when the intrinsic viscosity of the molten resin R is 0.01 dL / g or more above the target value.

[0060] On the other hand, if the intrinsic viscosity of the molten resin R is lower than a predetermined value, the control device 50 may lower the holding pressure of the injection molding apparatus 30, shorten the holding pressure time, or lower the temperature of the molten resin R (resin temperature). By adjusting at least one of the holding pressure and holding pressure time, the resin product can be maintained at the target weight and dimensions, and by adjusting the resin temperature, it is possible to suppress the molten resin R from becoming too fluid. Furthermore, since it is possible to suppress the molten resin R from becoming too fluid, it is possible to suppress the generation of burrs on the resin product. The control device 50 may also control the molding conditions of the injection molding apparatus 30 when the IV value, which is the intrinsic viscosity of the molten resin R, falls to 0.005 dL / g or less below the target value, or when the IV value, which is the intrinsic viscosity of the molten resin R, falls to 0.01 dL / g or less below the target value.

[0061] Furthermore, if the b value measured by the color measuring device 5 is higher than a predetermined value, the control device 50 may lower the processing temperature of the decontamination device 3, increase the pressure inside the decontamination device 3, or shorten the processing time of the decontamination device 3. This can lower the b value of the molten resin R. When the resin flakes F are made from recycled polyester containing a bluing agent, the control device 50 may control the decontamination conditions of the decontamination device 3 when the b value measured by the color measuring device 5 is -2 or higher, or when the b value measured by the color measuring device 5 is 0 or higher. Also, when the resin flakes F are made from recycled polyester without a bluing agent, the control device 50 may control the decontamination conditions of the decontamination device 3 when the b value measured by the color measuring device 5 is +5 or higher, or when the b value measured by the color measuring device 5 is +3 or higher.

[0062] Furthermore, if the b value measured by the color measuring device 5 is higher than a predetermined value, the control device 50 may lower the resin temperature in the injection molding device 30 while increasing the holding pressure. This can reduce yellowing of resin products made from molten resin R. When the resin flakes F are made from recycled polyester containing a bluing agent, the control device 50 may control the molding conditions of the injection molding device 30 when the b value measured by the color measuring device 5 is -2 or higher, or when the b value measured by the color measuring device 5 is 0 or higher. Furthermore, when the resin flakes F are made from recycled polyester without a bluing agent, the control device 50 may control the molding conditions of the injection molding device 30 when the b value measured by the color measuring device 5 is +5 or higher, or when the b value measured by the color measuring device 5 is +3 or higher.

[0063] In these cases, the control device 50 may, for example, control the molding conditions of the injection molding apparatus 30 so that the holding pressure of the injection molding apparatus 30 increases when the b value increases, as shown in Figures 4 and 5. In this case, the holding pressure of the injection molding apparatus 30 may be changed according to the value of the intrinsic viscosity, as shown in Figures 4 and 5. Here, Figure 4 is a graph that shows a schematic relationship between the holding pressure of the injection molding apparatus 30, the b value of the molten resin R, the resin temperature in the injection molding apparatus 30, and the intrinsic viscosity of the molten resin R. Figure 5 is a graph that shows a schematic relationship between the holding pressure of the injection molding apparatus 30, the b value of the molten resin R, and the intrinsic viscosity of the molten resin R, and is a graph of the relationship shown in Figure 4 viewed along the "holding pressure" - "b value" plane in Figure 4.

[0064] Furthermore, the control device 50 may, for example, control the molding conditions of the injection molding apparatus 30 so that the resin temperature in the injection molding apparatus 30 decreases when the b value increases, as shown in Figures 4 and 6. Here, Figure 6 is a graph that shows a schematic relationship between the b value of the molten resin R and the resin temperature in the injection molding apparatus 30, and is a graph of the relationship shown in Figure 4 viewed along the "resin temperature" - "b value" plane in Figure 4.

[0065] Here, if the resin temperature in the injection molding apparatus 30 is lowered, the fluidity of the molten resin R may decrease. As a result, the weight of the resin product may become lighter (smaller in dimensions) than the designed weight. For this reason, as shown in Figures 4 and 7, the control device 50 may control the molding conditions of the injection molding apparatus 30 so that the holding pressure of the injection molding apparatus 30 increases when the resin temperature in the injection molding apparatus 30 is lowered. In this case, as shown in Figures 4 and 7, the holding pressure of the injection molding apparatus 30 may be changed according to the value of the intrinsic viscosity. Here, Figure 7 is a graph showing a schematic relationship between the holding pressure of the injection molding apparatus 30, the resin temperature in the injection molding apparatus 30, and the intrinsic viscosity of the molten resin R, and is a graph of the relationship shown in Figure 4 viewed along the "holding pressure" - "resin temperature" plane of Figure 4.

[0066] Furthermore, the control device 50 may, for example, control the molding conditions of the injection molding apparatus 30 so that the holding pressure of the injection molding apparatus 30 increases when the intrinsic viscosity of the molten resin R increases, as shown in Figure 8. Here, Figure 8 is a graph that schematically shows the relationship between the holding pressure of the injection molding apparatus 30 and the intrinsic viscosity of the molten resin R.

[0067] Furthermore, parameters for adjusting the decontamination conditions of the decontamination device 3 and the molding conditions of the injection molding device 30 (such as the processing temperature of the decontamination device 3) may be set within the control device 50 based on data such as intrinsic viscosity, b value, and resin product quality (weight, dimensions, presence or absence of burrs, etc.). In this case, the above parameters may be set within the control device 50 by machine learning.

[0068] Manufacturing methods for resin products Next, with reference to Figure 9, the operation of this embodiment, that is, the method for manufacturing resin products, will be explained.

[0069] First, resin flakes F are supplied to the decontamination device 3 (resin flake supply process, indicated by the symbol S1 in Figure 9). At this time, the resin flakes F are supplied from the resin supply device 2 to the decontamination device 3.

[0070] Next, the resin flakes F supplied to the decontamination device 3 are heated in the decontamination device 3 to produce decontaminated molten resin R (decontamination process, indicated as S2 in Figure 9). In this process, first, the resin flakes F supplied to the decontamination device 3 are heated under reduced pressure by a heating mechanism (not shown) within the decontamination device 3. As the resin flakes F are heated, any contaminants attached to them volatilize. This removes the contaminants from the resin flakes F. Furthermore, the resin flakes F melt as they are heated. In this way, decontaminated molten resin R is produced.

[0071] Next, the intrinsic viscosity of the molten resin R decontaminated by the decontamination device 3 is measured (intrinsic viscosity measurement step, indicated by S3 in Figure 9). At this time, the intrinsic viscosity of the molten resin R is measured by the intrinsic viscosity measuring device 4. The measured value of the intrinsic viscosity of the molten resin R measured by the intrinsic viscosity measuring device 4 is then transmitted as a signal to the control device 50. For example, the intrinsic viscosity may be measured multiple times, and the average value of the intrinsic viscosity measured 50 times may be used as the measured value of the intrinsic viscosity of the molten resin R.

[0072] Next, the color of the molten resin R decontaminated by the decontamination device 3 is measured (color measurement step, indicated by the symbol S4 in Figure 9). At this time, the b value of the molten resin R is measured by the color measuring device 5. The measured value of the color of the molten resin R measured by the color measuring device 5 is then transmitted as a signal to the control device 50. For example, the b value may be measured multiple times, and the average value of 50 b values ​​may be used as the measured value of the color of the molten resin R.

[0073] Next, the molten resin R, which has been decontaminated by the decontamination device 3, is used to form a resin product by the injection molding device 30 (resin product molding process, indicated by the symbol S5 in Figure 9). In this way, a resin product is obtained.

[0074] In this embodiment, the control device 50 controls at least one of the decontamination device 3 and the injection molding device 30 (control step, reference numeral S6 in Figure 9). In this case, the control device 50 may also control at least one of the decontamination conditions of the decontamination device 3 and the molding conditions of the injection molding device 30 based on the measured intrinsic viscosity and color. In this case, for example, by controlling the decontamination conditions of the decontamination device 3, the intrinsic viscosity and b value of the molten resin R can be kept within a predetermined range. Furthermore, by controlling the molding conditions of the injection molding device 30, the weight, dimensions, color, etc. of the resin product can be stabilized. Therefore, the quality of the resin product made from the molten resin R can be improved, and the quality of the resin product can be stabilized.

[0075] The control process described above (indicated by the symbol S6 in Figure 9) may be performed before the resin product molding process (indicated by the symbol S5 in Figure 9).

[0076] As described above, according to this embodiment, the resin product manufacturing system 1 includes a resin supply device 2 for supplying resin flakes F, a decontamination device 3 for producing molten resin R by decontaminating the resin flakes F supplied from the resin supply device 2, an intrinsic viscosity measuring device 4 for measuring the intrinsic viscosity of the molten resin R decontaminated by the decontamination device 3, an injection molding device 30 for injecting the molten resin R, and a control device 50 for controlling at least one of the decontamination conditions of the decontamination device 3 and the molding conditions of the injection molding device 30 based on the measured intrinsic viscosity. In this case, by controlling the decontamination conditions of the decontamination device 3, the intrinsic viscosity and b value of the molten resin R can be kept within a predetermined range. Furthermore, by controlling the molding conditions of the injection molding device 30, sink marks, burrs, yellowing, etc. of the resin product can be suppressed, and the weight, dimensions, or color of the resin product can be stabilized. Therefore, the quality of the resin product produced from the molten resin R can be improved, and the quality of the resin product can be stabilized.

[0077] However, even when the decontamination conditions of the decontamination device 3 are adjusted, the intrinsic viscosity and b-value of the molten resin R do not change immediately. In other words, even when the decontamination conditions of the decontamination device 3 are adjusted, there is a time lag before the intrinsic viscosity and b-value of the molten resin R reach the desired values. In contrast, by controlling the molding conditions of the injection molding device 30 along with the decontamination conditions of the decontamination device 3, it is possible to improve the quality of the resin product and stabilize the quality of the resin product more effectively.

[0078] In the above-described embodiment, an example was given in which the resin product manufacturing system 1 includes a resin supply device 2, a decontamination device 3, an intrinsic viscosity measuring device 4, a color measuring device 5, an injection molding device 30, and a control device 50, but the system is not limited to this. For example, as shown in Figure 10, the resin product manufacturing system 1 does not need to include a color measuring device 5. In this case, as shown in Figure 10, the resin product manufacturing system 1 may include a resin supply device 2, a decontamination device 3, an intrinsic viscosity measuring device 4, an injection molding device 30, and a control device 50. In this modified example, as shown in Figure 11, the resin product may be manufactured by a resin flake supply process (reference numeral S11 in Figure 11), a decontamination process (reference numeral S12 in Figure 11), an intrinsic viscosity measuring process (reference numeral S13 in Figure 11), a resin product molding process (reference numeral S14 in Figure 11), and a control process (reference numeral S15 in Figure 11). In this modified example, the quality of the resin product made from the molten resin R can be improved, and the quality of the resin product can be stabilized. In this modified example, the control step described above (reference numeral S15 in Figure 11) may also be performed before the resin product molding step (reference numeral S14 in Figure 11).

[0079] Furthermore, as shown in Figure 12, for example, the resin product manufacturing system 1 does not necessarily have to be equipped with an intrinsic viscosity measuring device 4. In this case, as shown in Figure 12, the resin product manufacturing system 1 may be equipped with a resin supply device 2, a decontamination device 3, a color measuring device 5, an injection molding device 30, and a control device 50. In this modified example, as shown in Figure 13, the resin product may be manufactured by a resin flake supply process (code S21 in Figure 13), a decontamination process (code S22 in Figure 13), a chromaticity measurement process (code S23 in Figure 13), a resin product molding process (code S24 in Figure 13), and a control process (code S25 in Figure 13). In this modified example as well, it is possible to improve the quality of the resin product made from molten resin R and to stabilize the quality of the resin product. In this modified example as well, the control process (code S25 in Figure 13) described above may be performed before the resin product molding process (code S24 in Figure 13).

[0080] It is also possible to combine the multiple components disclosed in each of the above embodiments and variations as needed. Alternatively, some components may be removed from all the components shown in each of the above embodiments and variations. [Explanation of Symbols]

[0081] 1. Resin product manufacturing system 2 Resin supply device 3. Decontamination equipment 4 Intrinsic viscosity measuring device 5-color measuring device 30 Injection molding equipment 50 Control device F Resin flakes R molten resin

Claims

1. In a resin product manufacturing system for producing resin products from resin flakes, A resin supply device that supplies the aforementioned resin flakes, A decontamination device for producing molten resin by decontaminating the resin flakes supplied from the resin supply device, An intrinsic viscosity measuring device for measuring the intrinsic viscosity of the molten resin that has been decontaminated by the decontamination device, An injection molding apparatus for injection molding the molten resin, A resin product manufacturing system comprising a control device that controls at least one of the decontamination conditions of the decontamination device and the molding conditions of the injection molding device based on the measured intrinsic viscosity.

2. If the intrinsic viscosity is higher than a predetermined value, the control device lowers the processing temperature of the decontamination apparatus, increases the pressure inside the decontamination apparatus, or shortens the processing time of the decontamination apparatus. The resin product manufacturing system according to claim 1, wherein if the intrinsic viscosity is lower than a predetermined value, the control device increases the processing temperature of the decontamination apparatus, decreases the pressure inside the decontamination apparatus, or lengthens the processing time of the decontamination apparatus.

3. If the intrinsic viscosity is higher than a predetermined value, the control device increases the resin temperature in the injection molding apparatus, increases the holding pressure, or lengthens the holding pressure time. If the intrinsic viscosity is lower than a predetermined value, the control device lowers the resin temperature in the injection molding apparatus, lowers the holding pressure, or shortens the holding pressure time, according to claim 1 or 2, for the resin product manufacturing system.

4. The system further includes a color measuring device for measuring the color of the molten resin that has been decontaminated by the decontamination device, The resin product manufacturing system according to claim 1, wherein the control device controls at least one of the decontamination conditions of the decontamination device and the molding conditions of the injection molding device based on the measured intrinsic viscosity and color.

5. The resin product manufacturing system according to claim 4, wherein the color measurement value measured by the color measuring device is the b value of the CIE-Lab color system, and if the b value is higher than a predetermined value, the control device lowers the processing temperature of the decontamination device, increases the pressure inside the decontamination device, or shortens the processing time of the decontamination device.

6. The resin product manufacturing system according to claim 4 or 5, wherein the color measurement value measured by the color measuring device is the b value of the CIE-Lab color system, and if the b value is higher than a predetermined value, the control device lowers the resin temperature in the injection molding apparatus.

7. In a resin product manufacturing system for producing resin products from resin flakes, A resin supply device that supplies the aforementioned resin flakes, A decontamination device for producing molten resin by decontaminating the resin flakes supplied from the resin supply device, A color measuring device for measuring the color of the molten resin that has been decontaminated by the decontamination device, An injection molding apparatus for injecting the molten resin, A resin product manufacturing system comprising a control device that controls at least one of the decontamination conditions of the decontamination device and the molding conditions of the injection molding device based on the measured color.

8. The resin product manufacturing system according to claim 7, wherein the color measurement value measured by the color measuring device is the b value of the CIE-Lab color system, and if the b value is higher than a predetermined value, the control device lowers the processing temperature of the decontamination device, increases the pressure inside the decontamination device, or shortens the processing time of the decontamination device.

9. The resin product manufacturing system according to claim 7 or 8, wherein the color measurement value measured by the color measuring device is the b value of the CIE-Lab color system, and when the b value is higher than a predetermined value, the control device lowers the resin temperature in the injection molding apparatus while increasing the holding pressure.

10. The process of supplying resin flakes to the decontamination equipment, A step of producing decontaminated molten resin by heating the resin flakes supplied to the decontamination apparatus in the decontamination apparatus, A step of measuring the intrinsic viscosity of the molten resin that has been decontaminated by the decontamination device, A step of molding a resin product using an injection molding machine with the molten resin that has been decontaminated by the decontamination device, The process includes controlling at least one of the decontamination apparatus and the injection molding apparatus using a control device, A method for manufacturing a resin product, comprising the step of controlling at least one of the decontamination apparatus and the injection molding apparatus, wherein the control device controls at least one of the decontamination conditions of the decontamination apparatus and the molding conditions of the injection molding apparatus based on the measured intrinsic viscosity.

11. The process further includes measuring the color of the molten resin that has been decontaminated by the decontamination device, A method for manufacturing a resin product according to claim 10, wherein in a step of controlling at least one of the decontamination apparatus and the injection molding apparatus, the control device controls at least one of the decontamination conditions of the decontamination apparatus and the molding conditions of the injection molding apparatus based on the measured intrinsic viscosity and color.

12. The process of supplying resin flakes to the decontamination equipment, A step of producing decontaminated molten resin by heating the resin flakes supplied to the decontamination apparatus in the decontamination apparatus, A step of measuring the color of the molten resin that has been decontaminated by the decontamination device, A step of molding a resin product using an injection molding machine with the molten resin that has been decontaminated by the decontamination device, The process includes controlling at least one of the decontamination apparatus and the injection molding apparatus using a control device, A method for manufacturing a resin product, comprising the step of controlling at least one of the decontamination apparatus and the injection molding apparatus, wherein the control device controls at least one of the decontamination conditions of the decontamination apparatus and the molding conditions of the injection molding apparatus based on the measured color.

Images