Method for manufacturing synthetic fiber filler containing high shell powder content

Abstract

The present invention provides a method for manufacturing a synthetic resin filler containing a high shell powder content, the method comprising: 1) a shell powder micronization step; 2) a shell powder pretreatment step; 3) a step of manufacturing shell powder-containing synthetic resin fibers; 4) a step of manufacturing shell powder-containing masterbatch by using the shell powder-containing fibers and synthetic resin; 5) a step of electrospinning the shell powder-containing masterbatch; and 6) a step of collecting a filler composed of the electrospun shell powder-containing synthetic fibers. The shell powder-containing filler thus obtained has a high shell powder content, enabling recycling of fishery by-products on a commercial scale and manufacturing of fillers having antibacterial and heat-retention effects of the shell powder.

Description

Method for manufacturing a synthetic fiber filler containing a high content of seashell powder

[0001] The present invention relates to a synthetic fiber material comprising seashell powder, and further relates to a method for manufacturing a synthetic fiber filler comprising a high content of seashell powder, which expands the utilization of fishery by-products and enables the production of a useful filler by enabling a high content of seashell powder to be included in a synthetic resin through micronization and pretreatment of the seashell powder.

[0002] Plastics are widely used in various fields, utilizing their respective performance capabilities. Based on their functionality and convenience, they are used as an essential and closely integrated element in the daily lives of modern people and across industries. However, serious environmental pollution issues have long been raised, such as the problems of incineration or landfilling of various waste films, foam products, and plastic containers discarded after use, as well as the leakage of endocrine disruptors and air pollution caused by the incomplete combustion of waste containing highly toxic dioxins. Recently, non-biodegradable plastics have been spreading into the ecosystem as fine particles over time, causing serious problems, and this backlash from plastics against humanity is becoming a serious issue.

[0003] Meanwhile, more than 300,000 tons of fishery byproducts, such as shells (e.g., shells of oysters, rock oysters, abalone, ark shells, Manila clams, scallops, pearl oysters, pearl mussels, cockles, etc.), are generated annually, and most of the generated shells are treated as industrial waste, with only a portion being recycled.

[0004] Furthermore, seashells are mostly left unattended or illegally dumped. Currently, due to difficulties such as securing landfill sites, they are not being properly disposed of and are instead being stockpiled or abandoned in vacant lots along the coast. These abandoned or illegally dumped shells cause serious pollution problems and damage the landscape. Moreover, the proliferation of microorganisms on the flesh attached to the shells leads to foul odors and leachate leakage, causing various environmental pollution issues and resulting in complaints from local residents. Consequently, this has emerged as a difficult environmental and social problem to resolve in the region, leading to an increasing demand for methods to dispose of these shells, as well as for their recycling and resource recovery.

[0005] Seashells are composed of about 94% calcium carbonate and have high adsorption capacity for heavy metals and organic matter, as well as characteristics that allow microorganisms to easily attach and grow. As a result, there are attempts to recycle and process them, and they are being utilized as fertilizer or animal feed, or applied as various backfill materials, soil conditioners, and neutralizing agents.

[0006] However, despite the recycling mentioned above, it is not being actively utilized due to negative perceptions regarding its effectiveness and methods, and more than 100,000 tons are still difficult to process in accordance with the Marine Dumping Prevention Act.

[0007] Research and development aimed at utilizing seashells as fiber materials has been continuously carried out, and attempts are being made to use seashell powder in the manufacture of some clothing materials, industrial fillers, and filter materials by melt-kneading it with synthetic resin to produce pellets and then extruding or injection molding them. However, the seashell content relative to the raw material remains at the level of 1 to 2 weight percent, which is far from sufficient to achieve the goal of recycling the waste seashell byproducts produced.

[0008] In Patent Document 1, seashell powder is utilized in the manufacture of functional PET fibers using recycled seashell powder, but the actual content is less than 1 wt% relative to the weight of the total composition, so the amount used is negligible.

[0009] In the case of masterbatch pellets used as raw materials for general injection and extrusion plastic materials, fillers such as seashell powder may be included up to 20 to 30 weight percent of the total composition weight, but this is possible because they are pellets intended for manufacturing extrusion or injection materials. On the other hand, when manufacturing fiber materials with a thickness of 3 μm or less, impurities such as seashell powder are substantially recognized as being limited to 2 to 3 weight percent of the total composition weight.

[0010] Fibers used as materials for clothing, bedding, and industrial filling must have excellent thermal insulation, volume, lightness, and tactile properties. To achieve this, it is desirable that the thickness of the synthetic fibers constituting the filling be 10㎛ or less, and an appropriate manufacturing method for producing such materials is to utilize the electrospinning method.

[0011] However, when performing melt electrospinning to manufacture ultrafine staple fibers, if the amount of shell powder corresponding to impurities exceeds 3 weight percent, electrospinning becomes practically impossible, and even if spinning is performed, the target fiber length cannot be achieved.

[0012] The reason is that the large particle size of the seashell powder contained in the synthetic resin makes it difficult to collect on the collector of the electrospinning device, and the extruded synthetic fibers are easily cut due to the uneven dispersion of the seashell powder.

[0013] The objective of the present invention is to achieve the recycling of seashell powder at a commercial level by enabling a high content of seashell powder during the manufacturing process of ultrafine fibers.

[0014]

[0015] (Prior Art Literature)

[0016] (Patent Document 1) Korean Publication No. 10-2020-0123305 (Published October 29, 2020)

[0017] (Patent Document 2) Korean Publication No. 10-2023-0174600 (Published December 28, 2023)

[0018] (Patent Document 3) Korean Patent Publication No. 10-1060866 (Published August 31, 2011)

[0019] To achieve the above objective, the present invention provides a method for manufacturing a synthetic resin filler containing a high content of seashell powder, characterized by comprising: 1) a finely powdering step of seashell powder; 2) a pretreatment step of seashell powder; 3) a step of manufacturing a synthetic resin fiber containing seashell powder; 4) a step of manufacturing a masterbatch containing seashell powder using the fiber containing seashell powder and a synthetic resin; 5) an electrospinning step of the masterbatch containing seashell powder; and 6) a step of collecting the filler of the electrospun synthetic fiber containing seashell powder.

[0020] The above-mentioned fine pulverization step of the shell powder involves the average particle size D of the shell powder. 97 It is characterized by being processed in the range of 1 to 10 µm to 0.1 to 1.0 µm.

[0021] The pretreatment step of the above shell powder is characterized by adding one or more selected from glycerol monostearate, sorbitan monooleate, and polysaccharide as a modifier in an amount of 0.05 to 3.00 weight%, preferably 0.05 to 2.50 weight%, based on the total weight of the shell powder.

[0022] The fiber produced in the synthetic resin fiber manufacturing step containing the above-mentioned shell powder is characterized by having a fiber content of 3 to 6 g / Denier and a fiber length of 51 to 70 mm.

[0023] The above masterbatch containing shell powder is characterized by containing 5 to 10 weight percent of shell powder relative to the total weight of the synthetic resin.

[0024] The electrospun synthetic fiber filler containing shell powder collected by electrospinning using the shell powder masterbatch manufactured in this way is characterized by having a diameter of 0.5 to 3.0 μm and a fiber length of 5 to 50 mm.

[0025] According to the present invention, compared to conventional fibers containing shell powder with a shell content of 3 weight% or less, the recycling rate of shell by-products can be significantly increased to 5 to 10 weight%, and can contribute to generating additional revenue.

[0026] Since seashells are porous fillers, the higher the content, the better the thermal insulation, making it possible to manufacture a filling material that exhibits excellent thermal insulation as a filling material for winter clothing and bedding.

[0027] In addition, by manufacturing microfiber-level fillers containing a high content of seashell powder—which is generally considered an impurity in fibers and was previously impossible to produce in conventional fiber manufacturing processes—fillers can be utilized for various applications, such as clothing, bedding, and industrial materials (soundproofing materials, shock absorbers).

[0028] Figure 1 is a flowchart of the manufacturing process of a synthetic resin filler containing a high content of seashell powder according to the present invention.

[0029] Figure 2 is a photograph of an intermediate material at the manufacturing stage of a synthetic resin filler containing a high content of seashell powder according to the present invention.

[0030] Figure 3 is a micrograph of a short fiber shape and data on diameter and heat retention rate obtained by submitting a synthetic resin filler containing a high content of seashell powder according to the present invention to a testing institution (KOTITI).

[0031] Specific structural or functional descriptions of embodiments of the present invention disclosed in this specification or application are merely illustrative for the purpose of explaining embodiments according to the present invention, and embodiments according to the present invention may be implemented in various forms and should not be interpreted as being limited to the embodiments described in this specification or application.

[0032] Since embodiments according to the present invention may be subject to various modifications and may take various forms, specific embodiments are illustrated in the drawings and described in detail in this specification or application. However, this is not intended to limit embodiments according to the concept of the present invention to specific disclosed forms, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention.

[0033] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this specification.

[0034] Referring to FIGS. 1 and 2, the present invention relates to a method for manufacturing a synthetic resin filler containing a high content of seashell powder, characterized by comprising: 1) a finely powdering step of seashell powder; 2) a pretreatment step of seashell powder; 3) a step of manufacturing a synthetic resin fiber containing seashell powder; 4) a step of manufacturing a masterbatch containing seashell powder using the fiber containing seashell powder and a synthetic resin; 5) an electrospinning step of the masterbatch containing seashell powder; and 6) a step of collecting the filler of the electrospun synthetic fiber containing seashell powder.

[0035] The pulverization treatment step of the above-mentioned shell powder is a process of collecting, washing, drying, and grinding shells to obtain general shells, and then grinding the supplied shells again to produce a target particle size. The general shell powder used in the present invention has a particle size D. 97 This is 1~10㎛. This seashell powder is ground using a Jet Mill to obtain particle size D 97 This is finely pulverized to 0.1~1.0㎛. Here, D 97 D refers to the particle size value up to when the cumulative distribution percentage reaches 97%. 97 This means that the total number of particles smaller than the particle size in accounts for 97%.

[0036] Particle size D resulting from grinding using a Jet Mill 97 If this exceeds 1.0㎛, even if the applied voltage of electrospinning is increased, a problem arises in which the amount of ultrafine fibers collected at the collector is small and the average fiber length does not reach the target. In addition, D 97 When the particle size is less than 0.1㎛, it takes a long time to grind, and because it is ground into fine particles, it causes a large production loss in the subsequent modifier treatment process and leads to problems such as reduced dispersibility as the aggregation characteristics are strengthened.

[0037] As described above, the finely pulverized seashell powder undergoes a pretreatment process using a modifier in which one or more selected from glycerol monostearate, sorbitan monooleate, and polysaccharide are added and mixed in an amount of 0.05 to 3.00 wt%, preferably 0.05 to 2.50 wt%, relative to the total weight of the seashell powder in water. The finely pulverized seashell powder and the modifier are fed together into a mixer and then ultrasonically treated for 1 to 2 hours using a continuous ultrasonic treatment device to mix them so that the modifier is bound to the seashell powder. The prepared pretreated seashell powder is dried at 80 to 100°C to produce a powder state.

[0038] Shell powder is a filler primarily composed of calcium carbonate that has a strong tendency to aggregate while easily adsorbing moisture. Therefore, in the masterbatch process where shell powder is mixed with synthetic resin and extruded to produce pellets, moisture adsorbed within the shell powder evaporates during the high-temperature extrusion process. This can lead to the formation of bubbles within the pellets or cause depolymerization issues, posing a high risk of degrading the physical properties of the manufactured synthetic fibers. Recognizing this problem, a pretreatment process involving the binding of a modifier to the shell powder can prevent moisture adsorption and reduce aggregation, thereby preventing potential issues caused by moisture binding in advance.

[0039] If the amount of modifier used is less than 0.05 weight%, the amount of modifier bound to the surface of the shell powder is insufficient, which increases the likelihood of aggregation of the shell powder and the likelihood of moisture adsorption, and if it exceeds 2.50 weight%, the modifier acts as an impurity within the synthetic fiber, causing a problem of degrading mechanical properties.

[0040] The process involves the step of manufacturing synthetic resin fibers by mixing and melt-spinning the modified shell powder with synthetic resin. Conventional prior art regarding synthetic fibers containing shell powder generally involves directly mixing and melt-extruding the shell powder and synthetic resin to form synthetic resin pellets, and then manufacturing synthetic fibers by blending and melt-spinning these pellets with virgin synthetic resin.

[0041] However, when manufacturing synthetic fibers in this way, it is not only impossible to include 3 weight percent or more of shell powder relative to the weight of the synthetic resin, but it is also practically impossible to manufacture ultrafine fibers by including 1 weight percent or more of shell powder in electrospinning. For this reason, it has been recognized that it is impossible to manufacture fibers containing 3 weight percent or more of shell powder, which is a commercial level, especially ultrafine fibers with a thickness of 3 μm or less.

[0042] The reason is that in the spinning process of synthetic resin, impurities such as seashell powder drastically alter the flowability of the molten synthetic resin, which has a fatal effect on the spinning characteristics. Consequently, the spin orientation of the spun fibers decreases, and as a result, the degree of crystallinity decreases, leading to poor mechanical properties of the spun fibers and resulting in process defects.

[0043] To solve these problems, the inventors added a separate synthetic fiber manufacturing step prior to the synthetic resin masterbatch (M / B) manufacturing step containing a high content of seashell powder. The synthetic resin fiber manufacturing step is a process of melt-spinning into coarse short fibers by mixing 60 to 70 weight % of synthetic resin and 30 to 40 weight % of pre-treated seashell powder. Using existing melt-spinning equipment, synthetic resin fibers are manufactured under mild conditions by extruding at a speed of 300 to 400 m / min at a temperature of 250 to 290°C to produce fibers with a size of 3 to 6 g / Denier and a fiber length of 51 to 70 mm. In this synthetic fiber manufacturing step containing seashell powder, the melted synthetic resin undergoes high temperature heat and pressure, which improves the degree of crystallinity and simultaneously improves the degree of orientation, thereby increasing the intrinsic viscosity (IV) and improving physical properties.

[0044] In addition, since the thickness of the spun fiber is 3 to 6 g / Denier, even when the content of the shell powder dispersed in the synthetic fiber is high at 30% by weight or more, it is possible to spin to the target size without cutting or process defects occurring during the spinning process.

[0045] A masterbatch (M / B) containing shell powder is manufactured by mixing the fiber containing the shell powder produced in this manner with a virgin synthetic resin in a specific weight ratio and extruding it. The virgin synthetic resin used here is the same as the base synthetic resin used when manufacturing the fiber containing the shell powder.

[0046] The synthetic resin is a thermoplastic resin capable of melt spinning and is not particularly limited, but preferably polyethylene terephthalate (PET), polypropylene (PP), and polyethylene (PE) may be used.

[0047] The method for manufacturing the above masterbatch involves using a twin-screw extruder to feed virgin synthetic resin and fibers containing seashell powder into separate hoppers, moving the molten resin from the input side to the output side while extruding it under high pressure, cooling it, and cutting it into pellets to produce the masterbatch.

[0048] The masterbatch containing shell powder produced in this way is manufactured to contain 5 to 10 weight percent of shell powder relative to the total weight of the synthetic resin. Since this masterbatch containing shell powder is manufactured as a fiber first, and the degree of orientation is improved and crystallization proceeds, the dispersion of the shell powder is more uniform, and the physical properties of the masterbatch are improved, so even if a high content of shell powder of 5 weight percent or more is included in the next step, electrospinning, it is easy to electrospun and can be manufactured into ultrafine fibers.

[0049] On the other hand, in the above synthetic resin fiber manufacturing step, it is also possible to melt-spun into short fibers of coarse fineness by mixing 80 to 90 weight percent of synthetic resin and 10 to 20 weight percent of pre-treated shell powder. In this case, a masterbatch containing shell powder can be manufactured by supplying and extruding the synthetic resin fiber containing shell powder alone without adding a separate virgin synthetic fiber in the masterbatch manufacturing step.

[0050] Electrospinning is performed using a general electrospinning device, in which masterbatch pellets are fed into a heating chamber and maintained at a temperature of 270 to 300°C, and then melt-spun under voltage conditions of 15 to 30 kV applied from a high-voltage regulator. The melt-spun molten synthetic resin is continuously collected from the spinning nozzle to the collector and solidified to form a fiber web.

[0051] At this time, a conveyor-shaped bed is formed in a horizontal direction in the collector, and synthetic fibers containing seashell powder are stacked on top of it to form a web. At this time, the diameter of the ultrafine fibers containing seashell powder is 0.5 to 3.0 μm, and the fiber length is manufactured in the range of 5 to 50 mm. The ultrafine fibers on this web can be directly used as fillers, and on the other hand, functional additives such as flame retardants, heat-generating agents, and antibacterial agents can be treated on the ultrafine fibers on the web by a spray or immersion method, allowing for various applications such as clothing, bedding, industrial filters, and fillers depending on the intended use.

[0052] The present invention will be explained in more detail below through the following examples. However, the following examples are merely illustrative of the present invention and do not limit the scope of the present invention.

[0053]

[0054] <Example>

[0055] 1. Pretreatment Process - Shell powder pulverization, modifier treatment

[0056] D by micronizing seashell powder 97 This 1.0㎛ shell powder was prepared.

[0057] Based on the total weight of the shell powder, 1.0 wt% of glycerol monostearate and 1.5 wt% of polysaccharide were added to a stirrer and ultrasonic treatment was performed for 1 to 2 hours using a continuous ultrasonic treatment device while stirring. After ultrasonic treatment, the shell powder was heated to a temperature of 90°C and dried to produce a modified shell powder.

[0058] 2. Manufacture of synthetic resin fibers containing seashell powder

[0059] 60 wt% of polyethylene terephthalate (PET) and 40 wt% of pretreated seashell powder were melt-kneaded and melt-spun at a speed of 300 m / min under a temperature of 250 to 290°C to produce synthetic resin fibers with a fiber length of 65 mm and a fiber length of 5 g / Denier.

[0060] In addition, 90% by weight of polyethylene terephthalate (PET) and 10% by weight of pretreated seashell powder were melt-kneaded and melt-spun at a speed of 300 m / min under a temperature of 250 to 290°C to separately produce synthetic resin fibers with a fiber length of 5 g / Denier and a fiber length of 55 to 65 mm.

[0061] 3. Manufacture of a masterbatch containing shell powder using fibers containing shell powder and synthetic resin

[0062] For 100 parts by weight of synthetic resin fiber containing 60% by weight of polyethylene terephthalate (PET) and 40% by weight of seashell powder, virgin polyethylene terephthalate (PET) was fed into a separate hopper to produce masterbatches with different seashell powder contents. For Example 1, 700 parts by weight of PET was fed into 100 parts by weight of synthetic resin fiber containing seashell powder, for Example 2, 471 parts by weight, and for Example 3, 300 parts by weight, and the masterbatches were produced by melt extrusion using a twin-screw extruder.

[0063] Example 4 used a synthetic resin fiber consisting of 90% by weight of polyethylene terephthalate (PET) and 10% by weight of pretreated seashell powder in the total composition, and a polyester masterbatch was prepared by melt-extruding and cutting it as is without adding separate virgin PET.

[0064] The composition and shell powder content of the above examples are shown in [Table 1].

[0065]

[0066] 4. Electrospinning of masterbatch containing shell powder and filler collection step

[0067] Electrospinning was performed using a general electrospinning device by introducing masterbatch pellets into a heating chamber and maintaining the temperature at 270–300°C, followed by melt spinning under voltage conditions of 15–30 kV applied from a high-voltage regulator. The melt-spun synthetic resin was solidified while continuously collecting it from the spinning nozzle to the collector to form a fiber web.

[0068] At this time, a conveyor-shaped bed is formed in a horizontal direction in the collector, and synthetic fibers containing shell powder are stacked on top of it to form a web. At this time, the diameter of the ultrafine fibers containing shell powder is 0.5 to 3.0 μm, and the fiber length is manufactured in the range of 5 to 50 mm.

[0069] Among the above examples, Example 2 exhibited excellent focusing characteristics without any major problems in electrospinning characteristics, whereas in the case of Example 3, it was confirmed that yarn breakage occurred frequently along with polymer swell at the tip of the spinning nozzle. Example 4 showed fewer process defects compared to Example 3, and considering workability and shell powder content, Example 2 was confirmed to be the most suitable.

[0070] The above-mentioned filler was submitted to a testing institution (KOTITI) to obtain the results shown in Fig. 3. The performance was evaluated by measuring the electron microscope image of the filler magnified to 3000x, the short fiber diameter, and the thermal insulation rate. The short fiber diameter was found to be 2.10–2.41㎛, and the thermal insulation rate (constant temperature method, %) was measured at 91.0–91.4%, confirming its excellence.

[0071] Although various preferred embodiments of the present invention have been described above with some examples, the descriptions of various embodiments described in the "Specific details for carrying out the invention" section are merely illustrative, and those skilled in the art to which the present invention pertains will understand that the present invention can be carried out with various modifications or equivalent embodiments from the above description.

[0072] In addition, since the present invention can be implemented in various other forms, the present invention is not limited by the description above. The above description is provided merely to make the disclosure of the present invention complete and to fully inform those skilled in the art of the scope of the present invention, and it should be understood that the present invention is defined only by each claim of the claims.

Claims

1. 1) Micronization treatment step of shell powder; 2) Pretreatment step of shell powder; 3) Manufacturing step of synthetic resin fiber containing seashell powder; 4) Step for manufacturing a masterbatch containing shell powder using fiber containing shell powder and synthetic resin; 5) Electrospinning step of the masterbatch containing shell powder; and 6) A method for manufacturing a synthetic resin filler containing a high content of shell powder, characterized by including a step of collecting the filler of electrospun synthetic fibers containing shell powder.

2. In Paragraph 1, A method for manufacturing a synthetic resin filler containing a high content of shell powder, characterized in that the pulverization treatment step of the shell powder above is performed such that the average particle size D97 of the shell powder is processed to a range of 1 to 10 μm to 0.1 to 1.0 μm.

3. In Paragraph 1, A method for manufacturing a synthetic resin filler containing a high content of shell powder, characterized in that the pretreatment step of the shell powder above involves adding one or more selected from glycerol monostearate, sorbitan monooleate, and polysaccharide as a modifying agent in an amount of 0.05 to 3.00 weight% based on the total weight of the shell powder.

4. In Paragraph 1, A method for manufacturing a synthetic fiber filler containing a high content of seashell powder, characterized in that the fiber produced in the synthetic resin fiber manufacturing step containing the above seashell powder has a fiber content of 3 to 6 g / Denier and a fiber length of 51 to 70 mm.

5. In Paragraph 1, A method for manufacturing a synthetic resin filler containing a high content of shell powder, characterized in that the masterbatch containing the above shell powder contains 5 to 10 weight percent of shell powder relative to the total weight of the synthetic resin.

6. In Paragraph 1, A method for manufacturing a synthetic fiber filler containing a high content of seashell powder, characterized in that the collected electrospun synthetic fiber filler containing seashell powder has a diameter of 0.5 to 3.0 μm and a fiber length of 5 to 50 mm.

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