Molding material for wrap film and method for manufacturing the same

Abstract

The present invention provides a molding material for wrap film and a method for manufacturing the same, which can suppress fluctuations and instability in the extrusion amount of wrap film and prevent discoloration, thermal degradation, and other issues from occurring in the wrap film. [Solution] A molding material for a wrap film comprising a virgin material having a polyvinyl chloride resin and additives for molding a wrap film, a crushed material formed by crushing the left and right ends removed from an extruded wrap film, and a pelletized material obtained by crushing and pelletizing the left and right ends of an existing wrap film that is unevenly wound on a paper tube, wherein the addition ratio of the crushed material and pelletized material is 4 wt% to 70 wt%, and the size of the crushed material is such that it can pass through the filter mesh of the crusher, which is 1 mm to less than 8 mm.

Description

Technical Field

[0001] The present invention relates to a molding material for a wrap film used in the production of a food packaging wrap film and a method for producing the same.

Background Art

[0002] For the preservation, drying, and prevention of foreign matter adhesion of cooked food, a packaging roll body for food packaging (not shown) is used. This packaging roll body has a transparent strip-shaped wrap film wound around a paper tube that is a core (see Patent Document 1).

[0003] When manufacturing such a packaging roll body for food packaging, although not shown, a predetermined molding material is put into an extrusion molding machine and melt-kneaded, and a strip-shaped molten resin is extruded from a T-die at the tip of this extrusion molding machine and sandwiched between a cooling roll and a pressure roll to form a wide transparent wrap film. The left and right side ends with low accuracy of this wrap film are cut and removed as unnecessary ears, and while cutting the wrap film from which these ears have been removed to a predetermined product width with a slit blade, it is wound around a paper tube set in a winding machine for a predetermined length. Then, by cutting and trimming the uneven left and right side ends of the wound wrap film, a packaging roll body for food packaging can be manufactured.

[0004] By the way, there are various demands for the production of the packaging roll body. However, simply discarding the ears and the like removed from the wrap film as they are cannot contribute to the realization of a recycling-oriented society. Therefore, there is a demand to effectively utilize the ears and the like as recycled resources. In view of this demand, conventionally, a method has been proposed in which a new virgin material containing a resin for wrap film molding and the ears and the like removed from the wrap film are blended to prepare a molding material, and a wrap film is manufactured using this molding material to reduce waste (see Patent Documents 2, 3, and 4).

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2018-193159 [Patent Document 2] Japanese Patent Publication No. 2024-073802 [Patent Document 3] Special Publication No. 2016-522099 [Patent Document 4] Japanese Patent Application Publication No. 54-118460 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, when preparing molding material by simply blending recycled tabs and other parts with new virgin material, while waste can be reduced, the amount of molten resin extruded from the T-die becomes unstable and fluctuates, and the thermal degradation of the tabs and other parts is accelerated, leading to problems such as discoloration and thermal degradation of the wrap film.

[0007] The present invention has been made in view of the above, and aims to provide a molding material for a wrap film and a method for manufacturing the same that can suppress fluctuations and instability in the extrusion amount of molten resin for molding a wrap film, and prevent discoloration, thermal degradation, etc. from occurring in the wrap film. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention includes a virgin material having a vinyl chloride resin and additives for molding a wrap film, a crushed material formed by crushing at least a portion of the molded wrap film, and a pelletized material obtained by crushing at least a portion of the wrap film wound on a core into pellets, wherein the addition ratio of the crushed material and pelletized material is 4 wt% or more and 70 wt% or less, and the size of the crushed material is such that it can pass through a filter mesh of 1 mm or more and less than 8 mm.

[0009] Furthermore, it is preferable that the bulk density of the molding material for the wrap film is 480 g / L or more and less than 800 g / L. Furthermore, it is preferable that the addition rate of crushed material is 2 wt% to 45 wt%, and the addition rate of pelletized material is 2 wt% to 25 wt%.

[0010] Furthermore, in order to solve the above problems, the present invention provides a method for manufacturing a wrap film molding material as described in claim 1 or 2, characterized in that when mixing and cooling the virgin material, 4 wt% to 70 wt% of crushed material and pelletized material are added to the virgin material.

[0011] Here, the wrap film in the claims is preferably formed as a single layer of polyvinyl chloride resin. The virgin material also contains various necessary additives in addition to the polyvinyl chloride resin. "At least a portion of the wrap film" includes the entire defective wrap film, the sides of the wrap film, and any parts that are not discolored or burnt.

[0012] The crushed material may be formed into small pieces or powder by crushing the sides recovered from molded wrap film, for example. Alternatively, the pelletized material may be formed by collecting the misaligned sides of existing wrap film that has been molded and unevenly wound onto a core, along with a portion of the core, crushing them, and then pelletizing them. Each numerical value includes measurement error if there is no difference in the effects of the present invention.

[0013] According to the present invention, since the molding material is manufactured by adding 4 wt% to 70 wt% of recycled crushed material and pellet material of different sizes to a new virgin material, it is possible to prevent instability in the amount of molten resin extruded from the die for the wrap film when the wrap film is extruded. [Effects of the Invention]

[0014] According to the present invention, it is possible to suppress fluctuations and instability in the extrusion amount of molten resin for wrapping film molding, thereby preventing discoloration and thermal degradation of the wrapping film. Furthermore, since the crushed material is small enough to pass through a filter mesh of 1 mm to less than 8 mm, the entanglement between the virgin material and the crushed material is improved, preventing fluctuations in the extrusion amount of molten resin pushed out from the die. In addition, it is possible to prevent fluctuations in the extrusion amount of molten resin due to classification between virgin material and pellet material.

[0015] According to the invention described in claim 2, since the bulk density of the molding material for the wrap film is 480 g / L or more and less than 800 g / L, the molding material can be smoothly supplied to the wrap film extruder, and the wrap film can be manufactured appropriately. Furthermore, since fluctuations and pulsations in the resin pressure of the molding material can be suppressed, stabilization of wrap film manufacturing can be expected. According to the invention described in claim 3, since the addition rate of crushed material is 2 wt% to 45 wt% and the addition rate of pellet material is 2 wt% to 25 wt%, it is possible to suppress fluctuations in the amount of molten resin extruded from the extruder die and reduce discoloration, burning, etc., of the wrap film.

[0016] According to the invention described in claim 4, when virgin material is mixed and cooled, crushed material and pellet material are added to the virgin material in an amount of 4 wt% to 70 wt%, thereby preventing deterioration of the dispersibility of the virgin material and eliminating the need for additional mixing work. [Modes for carrying out the invention]

[0017] The following describes preferred embodiments of the present invention. In this embodiment, the molding material for the wrap film includes three types of materials: a virgin material having a polyvinyl chloride resin and additives for molding the wrap film; a crushed material formed by crushing at least a portion of the molded wrap film; and a pelletized material obtained by crushing at least a portion of the wrap film wound on a paper tube into pellets. The addition ratio of the crushed material and pelletized material is 4 wt% to 70 wt%, thereby contributing to the achievement of SDG Goal 9 adopted at the UN Summit.

[0018] The wrap film, as in conventional examples, is extruded into a single layer of colorless, transparent strip using a molding material and wound in multiple layers on a paper tube, which serves as the core, in a flat winding method, with a width of 250 mm to 500 mm and a length of approximately 500 m to 1200 m. This wrap film is a flexible thin film with a thickness of 6 μm to 20 μm. The paper tube is formed into a cylindrical shape with excellent dustproof properties and surface smoothness, for example, by spiral winding recycled paper onto it.

[0019] Virgin molding materials are prepared into new powders using, for example, polyvinyl chloride (PVC) resin, which has excellent transparency, self-adhesion, and water resistance; plasticizers, which are additives that contribute to the flexibility of the wrap film; stabilizers, which are additives that slow down the decomposition rate of the wrap film; anti-fogging agents (surfactants), which are additives that prevent surface condensation of the wrap film; and lubricants, which are additives that improve the moldability of the wrap film. Examples of plasticizers include epoxidized vegetable oils, aliphatic polybasic acid esters, diisononyl adipate, and di-n-octyl adipate. Examples of stabilizers include calcium fatty acids.

[0020] Examples of anti-fogging agents for virgin materials include polyoxyethylene sorbitan fatty acid esters, alkyl sulfate esters such as sodium lauryl sulfate, polyglycerin fatty acid esters, sorbitan fatty acid esters, and polyoxyethylene alkyl ethers. Lubricants include metal stearate salts such as calcium stearate, magnesium stearate, and aluminum stearate.

[0021] The crushed material of the molding material is formed into powder by successively crushing the left and right side ends removed as unnecessary ears of a wrap film extruded with the same molding material during production by a crusher and a pulverizer, and functions to stabilize the extrusion amount of the molten resin extruded from the T-die of the extrusion molding machine by entraining the virgin material of the powder. This crushed material is preferably powder of a size that can pass through a filter mesh of 1 mm or more and less than 8 mm when, for example, unnecessary ears recovered from a wrap film are crushed by a rotatable blade in a pulverizing chamber constituting the pulverizer and fall through the filter mesh at the lower part of the pulverizing chamber.

[0022] This is because when the mesh of the filter mesh of the pulverizer is less than 1 mm, the entanglement property between the virgin material and the crushed material deteriorates and the extrusion amount of the molten resin fluctuates. On the other hand, when the mesh of the filter mesh of the pulverizer exceeds 8 mm, classification with the virgin material or pellet material occurs and the extrusion amount of the molten resin fluctuates. From the experimental results, the mesh of the filter mesh is preferably in the range of 1 mm or more and less than 8 mm, more preferably 1 mm or more and 7.5 mm or less, still more preferably 1 mm or more and 7 mm or less.

[0023] The addition rate of the crushed material is preferably in the range of 2 wt% or more and 45 wt% or less, more preferably 2 wt% or more and 37 wt% or less, still more preferably 3 wt% or more and 30 wt% or less with respect to the virgin material. This is because when the addition rate is outside the range of 2 wt% or more and 45 wt% or less, the extrusion amount of the molten resin fluctuates or coloring or burning occurs in the wrap film.

[0024] The pellet material of the molding material is formed by cutting the displaced left and right side ends of an existing wrap film extruded with the same molding material and wound unevenly around a paper tube, crushing them with a pulverizer, removing the paper powder of the paper tube with a screen mesh, and then pelletizing with a granulator.

[0025] When the pellet material is formed, paper dust from the paper tube is removed by a screen mesh. This is because, although the left and right edges of the wrap film, which are misaligned, are not cut along with the paper tube when the cutter blades are used, some paper dust from the paper tube may be mixed in because the cutter blades reach close to the edge of the paper tube. The pellet material is formed into pellet products because processing into pellet products allows any paper dust or other foreign matter mixed in the pellet products to be removed by the mesh of the pelletizing extruder, making them reusable.

[0026] The pellet material addition rate should be between 2 wt% and 25 wt% relative to the virgin material, preferably between 2 wt% and 23 wt%, and more preferably between 2 wt% and 20 wt%. This is because if the addition rate falls outside the range of 2 wt% to 25 wt%, the amount of molten resin extruded becomes unstable, resulting in discoloration and burning defects in the wrap film.

[0027] The optimal bulk density for the molding material of such wrap film is 480 g / L or more and less than 800 g / L, preferably 490 g / L or more and 780 g / L or less, and more preferably 500 g / L or more and 750 g / L or less. This is because if the bulk density of the molding material is less than 480 g / L, there will be insufficient supply of the molding material to the extrusion molding machine, making it impossible to form a wrap film. Conversely, if the bulk density of the molding material exceeds 800 g / L, the resin pressure of the molding material will fluctuate and pulsate, resulting in unstable film formation of the wrap film.

[0028] To measure the bulk density of a molding material, scoop up the molding material from the prepared hopper with a 1-liter cup, level off the raised portion of the molding material at the edge of the cup's opening, and measure the mass of the cup.

[0029] The optimal addition ratio of crushed material and pelletized material to the molding material is 4 wt% to 70 wt%, preferably 5 wt% to 60 wt%, and more preferably 5 wt% to 50 wt%, relative to the virgin material. This is because if the addition ratio of crushed material and pelletized material is outside the range of 4 wt% to 70 wt%, it will cause fluctuations in the extrusion amount of molten resin, resulting in defects such as discoloration and burning in the wrap film.

[0030] The weight of the virgin material should be 30 wt% to 96 wt%, preferably 40 wt% to 95 wt%, and more preferably 50 wt% to 95 wt%, considering the weight of the crushed material and pelletized material.

[0031] In the above configuration, when manufacturing the molding material for the wrap film, first, a Henschel mixer is prepared and virgin material powders of polyvinyl chloride resin, plasticizer, stabilizer, antifogging agent, lubricant, etc. are added and mixed.

[0032] After mixing the virgin powder, the mixed virgin material is transferred from the Henschel mixer to the cooling mixer for cooling. At this time, 4 wt% to 70 wt% of crushed material and pelletized material are added to the virgin material, and the molding material is produced by cooling while mixing the virgin material, crushed material, and pelletized material. The reason for adding the crushed material and pelletized material during the cooling of the virgin material is that if they are added before the virgin material is cooled, the dispersibility of the virgin material deteriorates. Conversely, if the crushed material and pelletized material are added after the virgin material is cooled, a new mixing process is required.

[0033] Once the molding material is manufactured, it can be transferred from the cooling mixer to a mixing tank for storage, and then, as needed, the molding material can be pneumatically transported from the mixing tank to the hopper of the extrusion molding machine.

[0034] Next, when manufacturing the wrap film, the manufactured molding material is fed from the hopper of the extruder into the cylinder and melted and kneaded. The strip-shaped molten resin is then extruded from the T-die at the tip of the extruder and sandwiched between adjacent cooling rolls and compression rolls to form a wide, colorless, transparent wrap film into a thin film. At the same time, the unreliable left and right ends of the formed wide wrap film are cut off and removed as unnecessary edges. After that, the wrap film from which the edges have been removed is wound onto a winding machine. The removed edges are fed into a crusher and crushed to form crushed material, which is then reused.

[0035] Next, when manufacturing packaging rolls for food packaging, the uneven left and right ends of the wrap film wound onto the winding machine can be trimmed. The cut left and right ends of the wrap film are then crushed in a crusher and pelletized in a granulator to form pellet material, which is then reused.

[0036] As described above, instead of simply blending ear sections and the like into virgin material to prepare the molding material, crushed material and pellet material of different sizes and shapes are blended in a predetermined ratio, and the molding material is manufactured by cooling while mixing the virgin material, crushed material, and pellet material. This not only improves productivity but also prevents fluctuations and instability in the amount of molten resin extruded from the T-die. Furthermore, it prevents discoloration and thermal degradation of the wrap film by accelerating thermal degradation.

[0037] The wrap film used in the above embodiment may be for household or commercial use. The filter mesh may be of the type attached to the shredder or a separate type. An antibacterial agent (e.g., glycerin fatty acid ester) may also be used as an additive to the virgin material. In the above embodiment, the side edges of the wrap film were cut off as unnecessary edges before shredding, but this is not the only way to do so. For example, if there are defective parts such as discoloration or burning on the wrap film, the wrap film can be removed from the paper tube, the defective parts with discoloration or burning can be removed, and the good parts without discoloration or burning can be shredded to make shredded material.

[0038] Furthermore, the molding material can be supplied directly from the cooling mixer to the hopper of the extrusion molding machine. Also, if there are no particular problems, the molding material can be manufactured by stirring and mixing virgin material, crushed material, and pellet material in the hopper of the extrusion molding machine. It is also possible to form a wrap film by sandwiching the molten resin between a plurality of adjacent cooling rolls and cooling it. Moreover, the manufacturing process of the above embodiments is not limited in any way to the order described. For example, parts of the manufacturing method may be deleted or the order of description may be changed. Furthermore, all technologies described herein are subject to patent protection through amendment or divisional application, etc. [Examples]

[0039] The following describes examples of the molding material for wrap film and the method for manufacturing the same according to the present invention, along with comparative examples. [Example 1] To manufacture the molding material for the wrap film, first, virgin polyvinyl chloride resin, plasticizer, stabilizer, antifogging agent, and lubricant were added to a Henschel mixer, and these powdered polyvinyl chloride resin, plasticizer, stabilizer, antifogging agent, and lubricant were mixed together.

[0040] After mixing the virgin material, the mixture was transferred from the Henschel mixer to a cooling mixer. 3 wt% of crushed material and 2 wt% of pelletized material were added to the 95 wt% virgin material, and the molding material was produced by cooling while mixing the virgin material, crushed material, and pelletized material.

[0041] The crushed material was formed by sequentially crushing the left and right ends of a wrap film, which was removed as unnecessary edges during manufacturing using the same molding material, in a crusher and a pulverizer. This crushed material was made into a size that could pass through the 4 mm filter mesh of the pulverizer. The pelletized material was formed by cutting the misaligned left and right ends of an existing wrap film, which was extruded using the same molding material and unevenly wound onto a paper tube, crushing it in a pulverizer, removing the paper dust from the paper tube, and then pelletizing it in a granulator.

[0042] After manufacturing the molding material, it was transferred from the cooling mixer to a mixing tank for storage, and then pneumatically transported from the mixing tank to the hopper of the extrusion molding machine. The bulk density of the pneumatically transported molding material was measured to be 550 g / L. This bulk density was measured by scooping the molding material from the hopper with a 1 liter metal cup, leveling the bulge of the molding material that had risen from the opening of the metal cup with the edge of the metal cup, and measuring the mass of the entire metal cup.

[0043] Next, in order to manufacture the wrap film, the manufactured molding material was fed from the hopper of an extrusion molding machine into a cylinder and melted and kneaded. A strip of molten resin was extruded from the T-die at the tip of the extrusion molding machine and sandwiched between a cooling roll and a compression roll to form a thin film of colorless, transparent wrap film [manufactured by Shin-Etsu Polymer Co., Ltd.: product name Polymerwrap]. The left and right edges of the formed wrap film, which were of low precision, were cut off as unnecessary edges, and then the wrap film from which the edges had been removed was wound onto a winding machine. After manufacturing the wrap film, we inspected it for any fluctuations in the extrusion volume, as well as for any discoloration or thermal degradation. The results are summarized in Table 1.

[0044] [Example 2] The procedure was basically the same as in Example 1, but 90 wt% virgin material was mixed with 7 wt% crushed material and 3 wt% pellet material. The virgin material, crushed material, and pellet material were mixed and cooled to produce the molding material. After producing the molding material, it was transferred from the cooling mixer to a compounding tank for storage, and then pneumatically transported from the compounding tank to the hopper of an extrusion molding machine. The bulk density of the pneumatically transported molding material was measured to be 600 g / L.

[0045] Next, a wrap film was manufactured in the same manner as in Example 1, and the manufactured wrap film was inspected for any variation in extrusion amount, discoloration, or thermal degradation. The results are summarized in Table 1.

[0046] [Example 3] The procedure was basically the same as in Example 1, but 70 wt% virgin material was mixed with 20 wt% crushed material and 10 wt% pellet material. The molded material was then produced by mixing the virgin material, crushed material, and pellet material while cooling. After producing the molded material, it was transferred from the cooling mixer to a compounding tank for storage, and then pneumatically transported from the compounding tank to the hopper of an extrusion molding machine. The bulk density of the pneumatically transported molded material was measured to be 700 g / L.

[0047] Next, a wrap film was manufactured in the same manner as in Example 1, and the manufactured wrap film was inspected for any variation in extrusion amount, discoloration, or thermal degradation. The results are summarized in Table 1.

[0048] [Example 4] The procedure was basically the same as in Example 1, but 50 wt% virgin material was mixed with 30 wt% crushed material and 20 wt% pellet material. The virgin material, crushed material, and pellet material were mixed and cooled to produce the molding material. After producing the molding material, it was transferred from the cooling mixer to a compounding tank for storage, and then the molding material was pneumatically transported from the compounding tank to the hopper of the extrusion molding machine. The bulk density of the pneumatically transported molding material was measured to be 500 g / L.

[0049] Next, a wrap film was manufactured in the same manner as in Example 1, and the manufactured wrap film was inspected for any variation in extrusion amount, discoloration, or thermal degradation. The results are summarized in Table 1.

[0050] [Example 5] The procedure was basically the same as in Example 1, but 70 wt% virgin material was mixed with 20 wt% crushed material and 10 wt% pellet material. The molded material was then produced by mixing the virgin material, crushed material, and pellet material while cooling. The size of the crushed material was changed to one that could pass through the 1.0 mm filter mesh of the crusher. After producing the molded material, it was transferred from the cooling mixer to a compounding tank for storage, and then the molded material was pneumatically transported from the compounding tank to the hopper of the extrusion molding machine. The bulk density of the pneumatically transported molded material was measured to be 750 g / L.

[0051] Next, a wrap film was manufactured in the same manner as in Example 1, and the manufactured wrap film was inspected for any variation in extrusion amount, discoloration, or thermal degradation. The results are shown in Table 1.

[0052] [Example 6] The procedure was basically the same as in Example 1, but 70 wt% virgin material was mixed with 20 wt% crushed material and 10 wt% pellet material. The molded material was then produced by mixing the virgin material, crushed material, and pellet material while cooling. The size of the crushed material was changed to one that could pass through the 7.0 mm filter mesh of the crusher. After producing the molded material, it was transferred from the cooling mixer to a compounding tank for storage, and then the molded material was pneumatically transported from the compounding tank to the hopper of the extrusion molding machine. The bulk density of the pneumatically transported molded material was measured to be 600 g / L.

[0053] Next, a wrap film was manufactured in the same manner as in Example 1, and the manufactured wrap film was inspected for any variation in extrusion amount, discoloration, or thermal degradation. The results are shown in Table 1.

[0054] [Comparative Example 1] To manufacture the molding material for the wrap film, first, virgin polyvinyl chloride resin, plasticizer, stabilizer, antifogging agent, and lubricant were added to a Henschel mixer and mixed. After mixing 100 wt% of the virgin material, the 100 wt% virgin material mixture was transferred from the Henschel mixer to a cooling mixer, and the molding material was manufactured by cooling while mixing the virgin material without adding any crushed or pelletized materials.

[0055] After manufacturing the molding material, it was transferred from the cooling mixer to a mixing tank for storage, and then pneumatically transported from the mixing tank to the hopper of the extrusion molding machine. The bulk density of the pneumatically transported molding material was measured to be 500 g / L. Next, we attempted to manufacture a wrap film (Shin-Etsu Polymer Co., Ltd.: product name Polymerap) using the molding material, but the extrusion volume of the wrap film fluctuated significantly. As a result, although it was possible to manufacture the wrap film, the film formation was completely unstable, raising serious doubts about its manufacturing and practicality. After manufacturing the wrap film, we inspected it for fluctuations in the extrusion volume, discoloration, and thermal degradation, and the results are summarized in Table 1.

[0056] [Comparative Example 2] To manufacture the molding material for the wrap film, first, virgin polyvinyl chloride resin, plasticizer, stabilizer, antifogging agent, and lubricant were added to a Henschel mixer and mixed. After mixing the virgin material, the mixed virgin material was transferred from the Henschel mixer to a cooling mixer, where 20 wt% virgin material, 50 wt% crushed material, and 30 wt% pellet material were added, and the molding material was manufactured by cooling while mixing the virgin material, crushed material, and pellet material.

[0057] The crushed material was formed by sequentially crushing the left and right ends of a wrap film, which was removed as unnecessary edges during manufacturing using the same molding material, in a crusher and a pulverizer. This crushed material is small enough to pass through the 4 mm filter mesh of the pulverizer. The pelletized material was formed by cutting the misaligned left and right ends of an existing wrap film, which was extruded using the same molding material and unevenly wound onto a paper tube, crushing it in a pulverizer, removing the paper dust from the paper tube, and then pelletizing it in a granulator.

[0058] After manufacturing the molding material, it was transferred from the cooling mixer to a mixing tank for storage, and then pneumatically transported from the mixing tank to the hopper of the extrusion molding machine. The bulk density of the pneumatically transported molding material was measured to be 200 g / L. This bulk density was measured by scooping the molding material from the hopper with a 1 liter metal cup, leveling the bulging portion of the molding material at the edge of the metal cup, and measuring the mass of the full metal cup.

[0059] Next, an attempt was made to manufacture a wrap film (Shin-Etsu Polymer Co., Ltd.: product name Polymer Wrap) using a molding material, but discoloration and burning occurred in the wrap film, making it impossible to manufacture the wrap film.

[0060] [Comparative Example 3] The procedure was basically the same as in Comparative Example 2, but 70 wt% virgin material was mixed with 20 wt% crushed material and 10 wt% pellet material. The molding material was produced by cooling these virgin material, crushed material, and pellet material while mixing them. The size of the crushed material was changed to one that could pass through the 0.5 mm filter mesh of the crusher.

[0061] After manufacturing the molding material, it was transferred from the cooling mixer to a mixing tank for storage, and then pneumatically transported from the mixing tank to the hopper of the extrusion molding machine. The bulk density of the pneumatically transported molding material was measured to be 800 g / L. Next, we attempted to manufacture a wrap film using a molding material, but the amount of wrap film extruded fluctuated, making it impossible to manufacture the wrap film.

[0062] [Comparative Example 4] The procedure was basically the same as in Comparative Example 2, but 70 wt% virgin material was mixed with 20 wt% crushed material and 10 wt% pellet material. The molding material was produced by cooling these virgin material, crushed material, and pellet material while mixing them. The size of the crushed material was changed to one that could pass through the 8.0 mm filter mesh of the crusher.

[0063] After manufacturing the molding material, it was transferred from the cooling mixer to a mixing tank for storage, and then pneumatically transported from the mixing tank to the hopper of the extrusion molding machine. The bulk density of the pneumatically transported molding material was measured to be 150 g / L. Next, we attempted to manufacture a wrap film using a molding material, but the amount of wrap film extruded fluctuated, making it impossible to manufacture the wrap film.

[0064] [Table 1]

[0065] 〔evaluation〕 In each of the examples, good quality wrap film could be manufactured appropriately, and no fluctuations in the extrusion amount of the wrap film, discoloration of the wrap film, or presence of heat-degraded materials were observed. In contrast, in Comparative Example 1, the crushed material and pelletized material were omitted, causing fluctuations in the amount of wrap film extruded and hindering the production of the wrap film. Furthermore, in Comparative Example 2, the mixing ratio of the crushed material and pelletized material was 80 wt%, exceeding 70 wt%, making it impossible to produce wrap film, and the presence of discoloration and burning was also observed.

[0066] In Comparative Example 3, the crushed material was of such fine size that it could pass through the 0.5 mm filter mesh of the crusher, causing fluctuations in the amount of wrap film extruded and making it impossible to manufacture wrap film. In contrast, in Comparative Example 4, the crushed material was of such large size that it could pass through the 8.0 mm filter mesh of the crusher, causing fluctuations in the amount of wrap film extruded and making it impossible to manufacture wrap film. [Industrial applicability]

[0067] The molding material for wrap film and the method for manufacturing the same according to the present invention are used in the field of wrap film manufacturing.

Claims

1. A molding material for a wrap film, comprising a virgin material having a polyvinyl chloride resin and additives for molding a wrap film, a crushed material formed by crushing at least a portion of the molded wrap film, and a pelletized material obtained by crushing at least a portion of the wrap film wound on a core into pellets, wherein the addition ratio of the crushed material and pelletized material is 4 wt% or more and 70 wt% or less, and the size of the crushed material is such that it can pass through a filter mesh of 1 mm or more and less than 8 mm.

2. A molding material for a wrap film according to claim 1, wherein the bulk density is 480 g / L or more and less than 800 g / L.

3. A molding material for a wrap film according to claim 1 or 2, wherein the addition rate of crushed material is 2 wt% or more and 45 wt% or less, and the addition rate of pellet material is 2 wt% or more and 25 wt% or less.

4. A method for producing a molding material for a wrap film according to claim 1 or 2, characterized in that when mixing and cooling the virgin material, 4 wt% to 70 wt% of crushed material and pelletized material are added to the virgin material.

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