Black polyester film and its manufacturing method

Abstract

To provide a black polyester film and a method for producing the same.SOLUTION: There is provided a method for producing a black polyester film which comprises: supplying a recycled polyester material; physically recycling a portion of the recycled polyester material to form physically recycled polyester chips having a first intrinsic viscosity; chemically recycling another portion of the recycled polyester material to form chemically recycled polyester chips having a second intrinsic viscosity less than the first intrinsic viscosity; mixing black recycled polyester chips, physically recycled polyester chips and chemically recycled polyester chips according to a predetermined viscosity to form a polyester chip raw material; and dissolving and extruding the polyester chip raw material to obtain a black polyester film having a predetermined intrinsic viscosity.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a black polyester film and a method for producing the same, and in particular to a black polyester film produced from physically recycled polyester resin and chemically recycled polyester resin, and a method for producing the same. [Background technology]

[0002] The most common conventional recycling method for waste polyethylene terephthalate (PET) bottles is the physical recycling method (also called mechanical recycling method). The physical recycling method mainly includes the following: First, the PET bottle waste is physically and mechanically crushed. Then, the crushed PET bottle waste is placed in a high-temperature environment and melted. Then, the melted PET bottle waste is granulated to form physically recycled polyester chips. The physically recycled polyester chips can be used in subsequent processing operations.

[0003] The physically recycled polyester chips produced by the physical recycling method usually have a relatively high intrinsic viscosity (IV). The method mainly used in the related art to adjust the intrinsic viscosity of the physically recycled polyester chips is the solid polymerization method. However, the solid polymerization method is only used to improve the intrinsic viscosity of the physically recycled polyester chips, and is not used to reduce the intrinsic viscosity of the physically recycled polyester chips. In addition, in the general film manufacturing process, the intrinsic viscosity of the polyester chips is limited to a certain range. The physically recycled polyester chips produced by the physical recycling method are usually only applicable to the bottle blowing process and the spinning process, and cannot be applied to the film extrusion process.

[0004] In order to adapt the physically recycled polyester chips to the film manufacturing process, the method mainly used in the related art is to further mix virgin polyester chips with the physically recycled polyester chips to reduce the overall intrinsic viscosity of the polyester material. However, this method cannot effectively increase the proportion of recycled polyester material used in the black polyester film, so that the final black polyester film product may not meet the requirements for environmental protection. That is, the proportion of recycled polyester is limited to a certain extent in the existing black polyester film, and this problem needs to be addressed. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a black polyester film and a method for producing the same. [Means for solving the problem]

[0006] In one embodiment, the present invention provides a method for producing a black polyester film. The method includes the following steps: providing a recycled polyester material; physically regenerating a portion of the recycled polyester material to form a physically recycled polyester chip; the physically recycled polyester chip has a first intrinsic viscosity; chemically regenerating another portion of the recycled polyester material to form a chemically recycled polyester chip; the chemically recycled polyester chip has a second intrinsic viscosity, the second intrinsic viscosity being lower than the first intrinsic viscosity; mixing the black recycled polyester chip, the physically recycled polyester chip, and the chemically recycled polyester chip to form a polyester chip raw material according to a predetermined intrinsic viscosity; melting and extruding the polyester chip raw material to form a black polyester film; the black polyester film has a predetermined intrinsic viscosity; the black polyester film has an intrinsic viscosity of 0.4 dL / g to 0.8 dL / g, an acid value of 10 mgKOH / g to 80 mgKOH / g, a surface roughness (Ra) of 1 nm to 300 nm, and a dynamic friction coefficient of 0.2 to 0.4.

[0007] In an embodiment, the present invention provides a black polyester film. The black polyester film is formed by mixing, melting, and extruding a physically recycled polyester resin and a chemically recycled polyester resin according to a predetermined intrinsic viscosity, and the black polyester film has the predetermined intrinsic viscosity. The predetermined intrinsic viscosity of the black polyester film is 0.40 dL / g to 0.80 dL / g. The black polyester film has an acid value of 10 mgKOH / g to 80 mgKOH / g, a surface roughness of 1 nm to 300 nm, and a dynamic friction coefficient of 0.2 to 0.4.

[0008] According to one embodiment of the present invention, the content of isophthalic acid in the black polyester film is 0.1 mol% to 7 mol% based on 100 mol% of the total amount of the black polyester film. The storage modulus of the black polyester film measured at 150° C. and 10 Hz is 1.5×10 9 dyne / cm 2 ~4.0×10 9 dyne / cm2 It is.

[0009] According to one embodiment of the present invention, the black polyester film has a haze greater than 80%, a light transmission less than 10%, and an optical density of 1.2 or greater.

[0010] According to one embodiment of the present invention, the content of biomass-derived ethylene glycol in the black polyester film is 5 wt% or less, based on 100 wt% of the total amount of the black polyester film.

[0011] In one embodiment, the present invention provides a black polyester film having a predetermined intrinsic viscosity of 0.40 dL / g to 0.80 dL / g, an acid value of 10 mgKOH / g to 80 mgKOH / g, a surface roughness of 1 nm to 300 nm, and a dynamic friction coefficient of 0.2 to 0.4.

[0012] According to one embodiment of the present invention, the content of isophthalic acid in the black polyester film is 0.1 mol% to 7 mol% based on 100 mol% of the total amount of the black polyester film. The storage modulus of the black polyester film at 150° C. and 10 Hz is 1.5×10 9 dyne / cm 2 ~4.0×10 9 dyne / cm 2 It is.

[0013] According to one embodiment of the present invention, the black polyester film has a haze greater than 80%, a light transmission less than 10%, and an optical density of 1.2 or greater.

[0014] According to one embodiment of the present invention, the content of biomass-derived ethylene glycol in the black polyester film is 5 wt% or less, based on 100 wt% of the total amount of the black polyester film. Effect of the Invention

[0015] In view of the above, the black polyester film and its manufacturing method provided by the present invention adopt the technical solution of "mixing black recycled polyester chips, physically recycled polyester chips, and chemically recycled polyester chips to form polyester chip raw materials according to a predetermined intrinsic viscosity", thereby controlling the predetermined intrinsic viscosity of the polyester chip raw materials to one suitable for the film extrusion process, and increasing the proportion of recycled polyester raw materials.

[0016] The features and technical contents of the present disclosure will become apparent from the following detailed description and drawings. However, the drawings provided are for illustrative purposes only and are not limiting. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic flow chart of a method for producing a black polyester film according to one embodiment of the present disclosure.

[0018] [Diagram 2] FIG. 2 is a schematic diagram of the molecular weight distribution of polyester chip feedstock according to one embodiment of the present disclosure.

[0019] [Diagram 3] FIG. 3 shows storage modulus test results for a black polyester film, according to one embodiment of the present disclosure.

[0020] [Figure 4] FIG. 4 shows storage modulus test results for a black polyester film according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, the embodiment of the "black polyester film and its manufacturing method" of the present disclosure will be described by a specific embodiment. The present disclosure will be apparent to a person skilled in the art from the contents disclosed herein. The present disclosure can be implemented or applied by other different specific embodiments. The details of the present specification can be modified or changed in various ways according to various viewpoints and applications without departing from the spirit of the present disclosure. In addition, it is noted that the drawings of the present disclosure are schematic drawings and are not drawn according to actual scale. The following description will further describe the technical contents of the present disclosure. However, the contents disclosed herein do not limit the protection scope of the present disclosure. In addition, the term "or" referred to in the present specification can include any and all combinations of one or more related descriptions according to the actual situation.

[0022] [Manufacturing method of black polyester film]

[0023] The present disclosure increases the proportion of recycled polyester materials used in black polyester films, thereby enabling black polyester film products to meet environmental protection requirements.

[0024] 1, according to one embodiment of the present disclosure, a method for producing a black polyester film is provided, which can effectively increase the proportion of recycled polyester materials used in the black polyester film, and the produced black polyester film has good processability. The method for producing a black polyester film includes steps S110 to S150. Note that the order of the steps and the actual operation method described in this embodiment can be adjusted as necessary and are not limited to those described in this embodiment.

[0025] Step S110 includes providing a recycled polyester material.

[0026] To form a reusable recycled polyester material, the polyester material recycling method includes collecting various types of polyester waste and sorting the polyester waste according to its type, color, and use. The polyester waste is then compressed and baled. The baled polyester waste is then transported to a waste disposal site. In this embodiment, the polyester waste is recycled PET bottles (r-PET). However, the present disclosure is not limited thereto.

[0027] The method for recycling polyester material further includes removing other objects (e.g., bottle caps, labels, adhesives) from the polyester waste. The polyester waste is then physically and mechanically crushed. The bottle caps, liners, and bottle bodies of different materials are then floated and separated. The crushed polyester waste is then dried to form a recycled polyester material product, such as recycled PET bottle flakes, to facilitate the subsequent film manufacturing process.

[0028] In other embodiment variations of the present disclosure, the recycled polyester material may be a processed recycled polyester material obtained, for example, by direct purchase.

[0029] As used herein, "polyester" and "polyester material" refer to any type of polyester, particularly aromatic polyester, and specifically refers herein to polyester derived from terephthalic acid and ethylene glycol, i.e., polyethylene terephthalate (PET).

[0030] Furthermore, the polyester may be, for example, polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), or polyethylene naphthalate (PEN), etc. In this embodiment, the polyester is preferably PET and / or PTT. A copolymer may also be used. The copolymer refers to a copolymer that can be obtained from two or more dicarboxylic acids and / or two or more glycol components.

[0031] In one embodiment of the present disclosure, the recycled PET bottle flakes contain isophthalic acid (IPA) as a diacid unit. Therefore, the finally formed black polyester film also contains IPA. Based on the total amount of the black polyester film being 100 mol%, the content of IPA in the black polyester film is 0.1 mol% to 7 mol%, preferably 0.5 mol% to 5 mol%.

[0032] In one embodiment of the present disclosure, the recycled PET bottle flakes contain biomass-derived ethylene glycol as a diol unit. Therefore, the finally formed black polyester film also contains biomass-derived ethylene glycol. Based on the total amount of the black polyester film being 100 wt%, the content of biomass-derived ethylene glycol in the black polyester film is 5 wt% or less. In addition, based on the total carbon in the black polyester film, the radioactive element (C 14 ) is less than 5% biomass-derived carbon.

[0033] In one embodiment of the present disclosure, the recycled PET bottle flakes contain a metal catalyst. Therefore, the finally formed black polyester film also contains a metal catalyst. The metal catalyst is at least one material selected from the group consisting of antimony (Sb), germanium (Ge), and titanium (Ti). Based on the total amount of the black polyester film being 100 wt%, the content of the metal catalyst in the black polyester film is 0.0003 wt% to 0.04 wt%.

[0034] Step S120 includes physically regenerating a portion of the recycled polyester material to form a physically recycled polyester chip. The physically recycled polyester chip has a first intrinsic viscosity. In this embodiment, the first intrinsic viscosity of the physically recycled polyester chip is usually 0.60 dL / g or more, preferably 0.65 dL / g to 0.90 dL / g, and particularly preferably 0.65 dL / g to 0.80 dL / g.

[0035] Specifically, the steps of producing physical recycled polyester chips include: physically and mechanically crushing a portion of recycled polyester material (e.g., r-PET bottle flakes) to reduce the time and energy required to melt the recycled polyester material; then, melting the crushed recycled polyester material in a single-screw extruder or a twin-screw extruder to bring the recycled polyester material into a molten state; then, filtering the molten recycled polyester material through a first sieve to remove solid impurities from the recycled polyester material, thereby granulating to form physical recycled polyester chips.

[0036] That is, the recycled polyester material is reformed by cutting, melting, filtering, and extruding in sequence, thus rearranging the polyester molecules of the original recycled polyester material to produce a plurality of physical regenerated polyester chips.

[0037] It should be noted that during physical remanufacturing, the polyester molecules of the recycled polyester material are merely rearranged, not reorganized. Therefore, the components (e.g., metal catalysts, slip agents, copolymerization monomers, etc.) contained in the original recycled polyester material are still contained in the physically recycled polyester material, and therefore the black polyester film finally formed also contains the above-mentioned components. Furthermore, the physically recycled polyester chips also retain the properties of the recycled polyester material itself.

[0038] Since the molecular weight of the recycled polyester material does not change much during physical remanufacturing, the recycled polyester material in the molten state has a relatively high viscosity and a relatively poor flowability, so that the filtration efficiency is likely to decrease if a sieve with a too small mesh size is used.

[0039] In order to improve the filtering performance, in this embodiment, the first sieve preferably has a mesh size of 10 μm to 100 μm. That is, the first sieve can filter solid impurities having a particle size larger than the mesh size. However, the present disclosure is not limited thereto.

[0040] Needless to say, the applicable range of intrinsic viscosity varies depending on the film-making process. Generally, physically recycled polyester chips (physically recycled polyester resin) obtained by physical remanufacturing have a higher intrinsic viscosity (0.60 dL / g or more). When using only physically recycled polyester chips (physically recycled polyester resin), the polyester chip raw material is only applicable to the bottle blowing process and spinning process, but not to the film extrusion process.

[0041] As a method for adjusting the intrinsic viscosity of physically recycled polyester chips, the solid polymerization method is mainly used in the related art, however, the solid polymerization method can only be used to increase the intrinsic viscosity of physically recycled polyester chips, and cannot be used to decrease the intrinsic viscosity of physically recycled polyester chips.

[0042] In one embodiment of the present disclosure, the chemically recycled polyester chips (chemically recycled polyester resin) obtained in the chemical recycling step S130 of the present disclosure have a relatively low intrinsic viscosity (0.65 dL / g or less). Therefore, by using both physically recycled polyester chips and chemically recycled polyester chips and adjusting the ratio of physically recycled polyester chips and chemically recycled polyester chips, the intrinsic viscosity of the polyester chip raw material can be adjusted and applied to the film extrusion process.

[0043] Step S130 includes chemically regenerating another portion of the recycled polyester material to form chemically recycled polyester chips. The chemically recycled polyester chips have a second intrinsic viscosity, and the second intrinsic viscosity of the chemically recycled polyester chips is lower than the first intrinsic viscosity of the physically recycled polyester chips. In this embodiment, the second intrinsic viscosity of the chemically recycled polyester chips is usually 0.65 dL / g or less, preferably 0.40 dL / g to 0.65 dL / g, and particularly preferably 0.50 dL / g to 0.65 dL / g.

[0044] Specifically, the steps of producing chemically recycled polyester chips include: cutting or crushing another part of the recycled polyester material (e.g., r-PET bottle flakes), thereby reducing the time and energy required for depolymerization of the recycled polyester material; then, putting the cut or crushed recycled polyester material into a chemical depolymerization solution to depolymerize the recycled polyester material and form a raw material mixture; then, filtering the raw material mixture through a second sieve to remove solid impurities from the recycled polyester material, thereby reducing the concentration of non-polyester impurities in the raw material mixture.

[0045] Next, the raw material mixture after filtering through the second sieve is subjected to an esterification reaction, and an inorganic additive and a copolymerizable compound monomer are added during the esterification reaction. Finally, the monomers and / or oligomers in the raw material mixture are repolymerized under specific reaction conditions, and granulated to form chemically recycled polyester chips. The liquid temperature of the chemical depolymerization liquid may be, for example, 160°C to 250°C. However, the present disclosure is not limited thereto. Furthermore, the mesh size of the second sieve is smaller than the mesh size of the first sieve.

[0046] In addition, the above-mentioned chemical depolymerization liquid may cause chain scission of polyester molecules in the recycled polyester material, resulting in the effect of depolymerization. Furthermore, a polyester composition having a relatively short molecular chain and an ester monomer consisting of one diacid unit and two diol units (e.g., bis(2-hydroxyethyl) terephthalate (BHET)) can be obtained. That is, the raw material mixture has a smaller molecular weight than the recycled polyester material.

[0047] In this embodiment, the chemical depolymerization liquid may be, for example, a solution of water, methanol, ethanol, ethylene glycol, diethylene glycol, or a combination thereof. However, the present disclosure is not limited thereto. For example, water is used for hydrolysis, and methanol, ethanol, ethylene glycol, and diethylene glycol are used for alcoholysis.

[0048] Furthermore, it is noted that, unlike physical recycling operations, chemical recycling operations involve "depolymerization and repolymerization of polyester molecules in recycled polyester materials," in which polyester molecules are depolymerized into molecules of relatively small molecular weight and then repolymerized into new polyester resin.

[0049] In another embodiment of the present disclosure, the chemically recycled polyester chips may be prepared by hydrolysis or supercritical fluid method, as well as the method described in the above embodiment. The hydrolysis method is carried out on recycled polyester material in an alkaline solution, and the polyester molecules are completely decomposed into monomers by controlling the temperature and pressure to a constant level and irradiating microwaves. The supercritical fluid method is to decompose recycled polyester material into a small amount of monomers and oligomers in methanol in a supercritical fluid state. The yield of monomers and oligomers is affected by the reaction temperature and reaction time.

[0050] Specifically, chemical recycling methods can depolymerize recycled polyester materials into smaller molecular weight monomers, so impurities (e.g., colloidal impurities and other non-polyester impurities) originally contained in the recycled polyester materials (e.g., r-PET bottle flakes) can be more easily filtered out than physical recycling methods.

[0051] In addition, the chemical remanufacturing operation can reduce the molecular weight of the recycled polyester material (e.g., by forming a polyester composition having shorter molecular chains and compound monomers), so that the recycled polyester material has a lower viscosity and improved flow characteristics after being depolymerized. Thus, the chemical recycle operation may use sieves having a smaller mesh size to remove impurities having a smaller particle size from the polyester material.

[0052] In order to improve the filtering performance, in this embodiment, the second sieve preferably has a mesh size of 10 μm to 30 μm. That is, the second sieve can filter solid impurities having a particle size larger than the mesh size. However, the present disclosure is not limited thereto.

[0053] Regarding the filtration of solid impurities, the physical recycling operation can filter out only the solid impurities with relatively large particle sizes in the recycled polyester material, while the chemical recycling operation can remove the solid impurities with relatively small particle sizes in the recycled polyester material, thus effectively improving the production quality of the black polyester film.

[0054] Specifically, the chemically recycled polyester chips produced by the chemical remanufacturing step usually have a relatively low inherent viscosity, and the inherent viscosity of the chemically recycled polyester chips can be relatively easily controlled and can be controlled to be lower than the inherent viscosity of the physically recycled polyester chips.

[0055] Step S140 includes mixing the black recycled polyester chips, the physically recycled polyester chips, and the chemically recycled polyester chips to form a polyester chip raw material according to a predetermined inherent viscosity.

[0056] The intrinsic viscosity of the polyester chip raw material is suitable for the film manufacturing process. Specifically, the intrinsic viscosity of the polyester chip raw material is 0.50 dL / g to 0.8 dL / g, preferably 0.50 dL / g to 0.60 dL / g. The predetermined intrinsic viscosity is 0.40 dL / g to 0.8 dL / g, preferably 0.50 dL / g to 0.65 dL / g.

[0057] Specifically, the black recycled polyester chips, the physical recycled polyester chips, and the chemically recycled polyester chips are mixed in a predetermined weight ratio according to a predetermined intrinsic viscosity, so that the mixed black recycled polyester chips, the physical recycled polyester chips, and the chemically recycled polyester chips have a predetermined intrinsic viscosity and are suitable for producing a black polyester film.

[0058] The black recycled polyester chips include a black additive selected from the group consisting of graphite powder, nano carbon black (NCB), carbon nanotubes, and graphene.

[0059] The black recycled polyester chips may be produced by a physical recycling process or a chemical recycling process. That is, the black recycled polyester chips include at least one of black physically recycled polyester chips and black chemically recycled polyester chips. The intrinsic viscosity of the black recycled polyester chips is 0.25 dL / g to 0.70 dL / g, preferably 0.3 dL / g to 0.65 dL / g. In a preferred embodiment, only black physically recycled polyester chips are used.

[0060] Specifically, the steps of producing the black physically recycled polyester chips include: melting a portion of the recycled polyester material to form a first molten mixture, adding a black additive to the first molten mixture to form a second molten mixture, and reforming the second molten mixture to form the black physically recycled polyester chips. Based on a total amount of 100 wt% of the black physically recycled polyester chips, the black physically recycled polyester chips include 5 wt% to 25 wt% of the black additive.

[0061] Specifically, the steps of producing the black chemically recycled polyester chips include: depolymerizing another portion of the recycled polyester material to form a first oligomer mixture, adding a black additive to the first oligomer mixture to form a second oligomer mixture, and repolymerizing the second oligomer mixture to form the black chemically recycled polyester chips. Based on a total amount of 100 wt% of the black chemically recycled polyester chips, the black chemically recycled polyester chips contain 5 wt% to 25 wt% of the black additive.

[0062] In order to increase the proportion of recycled polyester materials used, appropriate amounts of each of the above types of recycled polyester chips are used.

[0063] From the viewpoint of a predetermined weight ratio, the amount of physically recycled polyester chips used is preferably 50 to 95 parts by weight, and more preferably 75 to 95 parts by weight, based on 100 parts by weight of polyester chip raw material (i.e., all polyester chips). The amount of chemically recycled polyester chips used is preferably 5 to 50 parts by weight, and more preferably 5 to 25 parts by weight. However, the present disclosure is not limited thereto.

[0064] In a preferred embodiment, the amount of physically recycled polyester chips used is greater than the amount of chemically recycled polyester chips used, although the present disclosure is not limited thereto.

[0065] Step S150 includes melting and then extruding the polyester chip raw material, thereby forming a black polyester film, which has a predetermined intrinsic viscosity.

[0066] In the black polyester film, the physically recycled polyester chips (including the black physically recycled polyester chips) are molded into the physically recycled polyester resin. The chemically recycled polyester chips (including the black chemically recycled polyester chips) are molded into the chemically recycled polyester resin, and the black additives in the black recycled polyester chips are uniformly dispersed in the physically recycled polyester resin and the chemically recycled polyester resin.

[0067] According to the mixing ratio of step S140, based on the total amount of the black polyester film being 100 wt%, the content of the physically recycled polyester resin is preferably 50 wt% to 95 wt%, and particularly preferably 60 wt% to 80 wt%. The content of the chemically recycled polyester resin is preferably 5 wt% to 50 wt%, and particularly preferably 20 wt% to 40 wt%. The content of the black additive is 0.1 wt% to 6 wt%, and preferably 3 wt% to 6 wt%.

[0068] Furthermore, the total content of the physically recycled polyester resin and the chemically recycled polyester resin is 55 wt % to 100 wt %, and particularly preferably 70 wt % to 100 wt %.

[0069] According to the above-mentioned configuration, the method for producing the black polyester film of the present embodiment can use a high proportion of recycled polyester material, and does not require additional virgin polyester resin or only a small amount of virgin polyester resin is required. For example, in one embodiment of the present disclosure, the amount of virgin polyester resin used is usually 50 parts by weight or less, preferably 30 parts by weight or less, and particularly preferably 10 parts by weight or less.

[0070] In one embodiment of the present disclosure, the physically recycled polyester chips have a first acid value, and the chemically recycled polyester chips have a second acid value, the second acid value being greater than the first acid value. The first acid value is 10 mgKOH / g to 40 mgKOH / g, and the second acid value is 20 mgKOH / g to 70 mgKOH / g.

[0071] Specifically, referring to FIG. 2, the physically recycled polyester chips have a first molecular weight distribution 1, and the chemically recycled polyester chips have a second molecular weight distribution 2, which has a wider range than the first molecular weight distribution 1.

[0072] Furthermore, by combining physically recycled polyester chips and chemically recycled polyester chips, the polyester chip raw materials (black recycled polyester chips, physically recycled polyester chips, chemically recycled polyester chips) have a third molecular weight distribution 3, and the third molecular weight distribution 3 has a range between the first molecular weight distribution 1 and the second molecular weight distribution 2.

[0073] Specifically, from the viewpoint of molecular weight distribution, chemically recycled polyester chips have a relatively wide molecular weight distribution, which can improve the productivity of the film manufacturing process. However, the black polyester film produced using only chemically recycled polyester chips may have relatively poor physical properties (e.g., mechanical properties). In addition, the production cost of chemically recycled polyester chips is relatively high.

[0074] Physically recycled polyester chips have a relatively narrow molecular weight distribution, which may reduce the productivity of the film-making process. However, black polyester films produced using only physically recycled polyester chips may have relatively good physical properties. In other words, neither purely physical recycling nor purely chemical recycling is sufficient.

[0075] The method for producing a black polyester film according to an embodiment of the present disclosure is characterized by using both physically recycled polyester chips and chemically recycled polyester chips, which improves the productivity of the film-forming process, provides relatively good physical properties of the black polyester film, and reduces the production cost of the black polyester film.

[0076] Furthermore, the method for producing the black polyester film of the present invention further includes adding inorganic particles to the recycled polyester material during physical or chemical remanufacturing, and the finally formed black polyester film includes the inorganic particles.

[0077] In this embodiment, the inorganic particles are slipping agents. However, the present disclosure is not limited thereto. The slipping agent is at least one material selected from the group consisting of silicon dioxide particles, calcium carbonate particles, barium sulfate particles, polystyrene particles, silicone particles, and acrylic particles. Furthermore, based on a total amount of 100 wt% of the black polyester film, the content of the slipping agent is 0.01 wt% to 10 wt%.

[0078] [Black polyester film]

[0079] The manufacturing method of the black polyester film according to one embodiment of the present disclosure has been described above. The black polyester film according to one embodiment of the present disclosure will be described below. In this embodiment, the black polyester film is formed by the manufacturing method described above. However, the present disclosure is not limited thereto.

[0080] The material of the black polyester film includes a physically recycled polyester resin, a chemically recycled polyester resin, and a black additive. The physically recycled polyester resin is formed from physically recycled polyester chips, the physically recycled polyester chips having a first intrinsic viscosity. The chemically recycled polyester resin is formed from chemically recycled polyester chips, the chemically recycled polyester chips having a second intrinsic viscosity. The second intrinsic viscosity is lower than the first intrinsic viscosity. The black additive is dispersed between the chemically recycled polyester resin and the physically recycled polyester resin.

[0081] It is noted that the physically recycled polyester chips and the chemically recycled polyester chips are mixed based on a predetermined intrinsic viscosity to produce a black polyester film having a predetermined intrinsic viscosity.

[0082] In one embodiment of the present disclosure, the first intrinsic viscosity of the physically recycled polyester chips is 0.60 dL / g or more, the second intrinsic viscosity of the chemically recycled polyester chips is 0.65 dL / g or more, and the predetermined intrinsic viscosity is 0.45 dL / g to 0.75 dL / g.

[0083] In a preferred embodiment of the present disclosure, the first intrinsic viscosity of the physically recycled polyester chips is 0.65 dL / g to 0.80 dL / g, the second intrinsic viscosity of the chemically recycled polyester chips is 0.50 dL / g to 0.65 dL / g, and the predetermined intrinsic viscosity is 0.50 dL / g to 0.65 dL / g.

[0084] Furthermore, the black polyester film of the present disclosure has an acid value of 10 mgKOH / g to 80 mgKOH / g, preferably an acid value of 15 mgKOH / g to 75 mgKOH / g, and particularly preferably an acid value of 20 mgKOH / g to 70 mgKOH / g. The acid value of the black polyester film is measured based on ASTM D7409-15. When the acid value of the black polyester film is 10 mgKOH / g to 80 mg / KOH / g, the black polyester film exhibits heat resistance and hydrolysis resistance under a low acid value.

[0085] The black polyester film of the present disclosure has a surface roughness (Ra) of 1 nm to 300 nm, preferably 10 nm to 280 nm, and particularly preferably 15 nm to 260 nm. The surface roughness is measured in accordance with DIN EN ISO 4287 / 4288.

[0086] The black polyester film of the present disclosure has a dynamic friction coefficient of 0.2 to 0.4. The dynamic friction coefficient is measured in accordance with ASTM D1894.

[0087] If the surface roughness of the black polyester film is 1 nm to 300 nm and the dynamic friction coefficient is 0.2 to 0.4, the procedures of film formation, film recovery, and post-treatment of the black polyester film will be smoother.

[0088] The storage modulus of the black polyester film of the present disclosure at 150° C. and 10 Hz is 1.5×10 9 dyne / cm 2 ~4.0×10 9 dyne / cm 2 and preferably 1.8×10 9 dyne / cm 2 ~3.5×10 9 dyne / cm 2 and particularly preferably 2.0×10 9 dyne / cm 2 ~3.0×10 9 dyne / cm 2 The storage modulus of the black polyester film is the average value of the storage modulus of the black polyester film measured in the machine direction and the transverse direction by a dynamic viscoelasticity measuring device. Specific measurement results are shown in Figures 3 and 4.

[0089] In addition, the above-mentioned physical recycled polyester chips and chemically recycled polyester chips are both obtained by granulating recycled polyester material through recycling and reuse. The recycled polyester material is recycled PET bottle flakes.

[0090] In one embodiment of the present disclosure, the black polyester film has the following characteristics. Based on 100 mol% of the total amount of the black polyester film, the content of isophthalic acid in the black polyester film is 0.1 mol% to 7 mol%. Based on 100 wt% of the total amount of the black polyester film, the content of biomass-derived ethylene glycol in the black polyester film is 5 wt% or less. The optical density of the black polyester film is 1.2 or more. The surface roughness (Ra) of the black polyester film is 1 nm to 300 nm. The haze of the black polyester film is more than 80%. The dynamic friction coefficient of the black polyester film is 0.2 to 0.4.

[0091] The black polyester film and its manufacturing method provided by the present invention adopt the technical solution of "mixing black recycled polyester chips, physically recycled polyester chips, and chemically recycled polyester chips to form polyester chip raw materials according to a predetermined intrinsic viscosity", which allows the predetermined intrinsic viscosity of the polyester chip raw materials to be controlled to be suitable for the film extrusion process, and the proportion of recycled polyester raw materials to be increased.

[0092] The above description is only for the preferred and possible embodiments of the present disclosure, and therefore does not limit the scope of the present disclosure. All equivalent technical modifications made from the specification and drawings of the present disclosure shall be included in the scope of the present disclosure. [Industrial Applicability]

[0093] The black polyester film of the present invention and / or the method for forming the black polyester film from the recycled polyester material can be applied to the polyester recycling industry.Furthermore, the black polyester film from the recycled polyester material of the present invention can be applied to any commercially available object (such as magnetic tape, insulating tape, photographic film, tracing film, packaging film, electrical insulating film, engineering paper, etc.). [Explanation of symbols]

[0094] S110, S120, S130, S140, S150 Step 1. First molecular weight distribution 2. Second Molecular Weight Distribution 3. The third molecular weight distribution

Claims

1. providing a recycled polyester material; physically regenerating a portion of the recycled polyester material to form physically regenerated polyester chips having a first intrinsic viscosity; chemically regenerating another portion of the recycled polyester material to form chemically regenerated polyester chips having a second intrinsic viscosity lower than the first intrinsic viscosity; mixing the black recycled polyester chips, the physically recycled polyester chips, and the chemically recycled polyester chips to form a polyester chip raw material having a predetermined intrinsic viscosity; melting and extruding the polyester chip feedstock to form a black polyester film having a predetermined intrinsic viscosity; Equipped with the first intrinsic viscosity is 0.65 dL / g to 0.90 dL / g, the second intrinsic viscosity is 0.40 dL / g to 0.65 dL / g, and the black polyester film has an intrinsic viscosity of 0.4 dL / g to 0.8 dL / g, an acid value of 10 mg KOH / g to 80 mg KOH / g, a surface roughness of 1 nm to 300 nm, and a dynamic friction coefficient of 0.2 to 0.4; A method for producing black polyester film.

2. A black polyester film formed by mixing, melting, and extruding physically recycled polyester chips having a first intrinsic viscosity and chemically recycled polyester chips having a second intrinsic viscosity smaller than the first intrinsic viscosity according to a predetermined intrinsic viscosity, the first intrinsic viscosity is 0.65 dL / g to 0.90 dL / g, the second intrinsic viscosity is 0.40 dL / g to 0.65 dL / g, and the black polyester film has a predetermined intrinsic viscosity; The black polyester film has a predetermined intrinsic viscosity of 0.40 dL / g to 0.80 dL / g, an acid value of 10 mgKOH / g to 80 mgKOH / g, a surface roughness of 1 nm to 300 nm, and a dynamic friction coefficient of 0.2 to 0.

4. Black polyester film.

3. The content of isophthalic acid in the black polyester film is 0.1 mol% to 7 mol% based on 100 mol% of the total amount of the black polyester film; The storage modulus of the black polyester film at 150° C. and 10 Hz is 1.5×10 ９ dyne / cm ２ ~4.0 x 10 ９ dyne / cm ２ That is, The black polyester film of claim 2.

4. 3. The black polyester film of claim 2 having a haze greater than 80%, a light transmission less than 10%, and an optical density of 1.2 or greater.

5. 3. The black polyester film of claim 2, wherein the content of the biomass-derived ethylene glycol in the black polyester film is 5 wt % or less based on 100 wt % of a total amount of the black polyester film.

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