KR102654493B1 - Thermoplastic resin composition comprising fiber network structure and method for manufacturing the same - Google Patents

Abstract

One aspect of the present invention includes the steps of mixing a fiber suspension and a polymer resin to obtain an aqueous dispersion; Obtaining a first intermediate having a moisture content of 20% by weight or less by drying the aqueous dispersion; Melting and kneading the first intermediate to obtain a second intermediate; And drying the second intermediate to obtain a third intermediate having a water content of 3% by weight or less; a method for producing a thermoplastic resin composition comprising a fiber forming a three-dimensional network structure; and a continuous polymer resin matrix permeating the network structure. The thermoplastic resin composition includes a water content of 3% by weight or less.

Description

Thermoplastic resin composition containing a fiber network structure and method for manufacturing the same {THERMOPLASTIC RESIN COMPOSITION COMPRISING FIBER NETWORK STRUCTURE AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to a thermoplastic resin composition containing a fiber network structure and a method for manufacturing the same, and specifically, to improve the dispersibility, compatibility, and processability of the main resin of eco-friendly fiber materials, and at the same time to produce a product obtained by molding the same. It relates to a thermoplastic resin composition containing a fiber network structure that can improve mechanical properties.

Cellulose is one of the renewable, eco-friendly materials obtained from biomass. In particular, cellulose fibers account for nearly half of the weight fraction in most plants. Therefore, research is being actively conducted to apply cellulose fibers as reinforcing materials for molded products using thermoplastic resins.

By applying mechanical pressure to a low concentration of cellulose using a high-pressure homogenizer, a fiber suspension in which cellulose nanofibers are dispersed can be obtained. Cellulose nanofibers have a high aspect ratio and thus excellent mechanical strength, and are thermally stable, so it is believed that they can be used as fillers to make lightweight composites.

However, cellulose nanofibers are strongly physically entangled inside the fiber suspension, forming a kind of three-dimensional network structure. Therefore, when dried and used as a reinforcing material, there is a problem in that it is not dispersed but aggregates within the main resin. As a result, the melt viscosity of the resin composition in which cellulose nanofibers are dispersed increases excessively, making it difficult to obtain sufficient processability.

In addition, due to the lack of uniformity in dispersion, molded bodies manufactured by adding cellulose nanofibers have the problem of lowering tensile strength and impact strength due to greater variation in mechanical strength for each part.

Polyolefin resin is widely used as the most common thermoplastic polymer. In addition, in order to supplement the impact resistance of polyolefin resin products, polyolefin elastomers (POE) are copolymerized with ethylene and low-density α-olefins, such as 1-octene and/or 1-butene, using a metallocene catalyst. Various methods for manufacturing are being proposed.

However, due to the nature of the majority of polyolefin-based polymers, which are inherently hydrophobic, there is a problem in that they lack affinity when applying cellulose nanofibers, resulting in interfacial peeling and phase separation phenomena. To solve this problem, a technology has been proposed to hydrophobize cellulose nanofibers by modifying them. However, due to the strongly physically entangled nature of cellulose nanofibers, there is a limit to improving dispersibility through chemical modification alone.

The present invention is intended to solve the problems of the prior art described above. The purpose of the present invention is to improve the dispersibility, compatibility, and processability of eco-friendly fiber materials in the main resin, and at the same time improve the mechanical properties of products obtained by molding them. The aim is to provide a thermoplastic resin composition containing a fiber-resin masterbatch that can contribute to product productivity and economic efficiency.

One aspect of the present invention includes the steps of mixing a fiber suspension and a polymer resin to obtain an aqueous dispersion; Obtaining a first intermediate having a moisture content of 20% by weight or less by drying the aqueous dispersion; Obtaining a second intermediate by melting and kneading the first intermediate; and drying the second intermediate to obtain a third intermediate having a moisture content of 3% by weight or less.

In one embodiment, the fiber suspension may satisfy at least one of the following conditions (i) to (iv): (i) a solid content of 50% by weight or more; (ii) thermal decomposition temperature of 300°C or higher; (iii) contact angle greater than 110°; (iv) Inorganic content of 30% by weight or less.

In one embodiment, the polymer resin may be a modified polyolefin having an acid value of 60 to 150 mgKOH/g.

In one embodiment, at least one of obtaining the aqueous dispersion and melt-kneading the first intermediate may be performed at 70 to 180°C.

In one embodiment, at least one of drying the aqueous dispersion and drying the second intermediate may be performed at 100°C or lower.

In one embodiment, the step of mixing the third intermediate with a composition including a main resin and a reinforcing material may be further included.

Another aspect of the present invention is a fiber forming a three-dimensional network structure; and a continuous polymer resin matrix permeating the network structure. The thermoplastic resin composition includes a water content of 3% by weight or less.

In one embodiment, the polymer resin may be a modified polyolefin having an acid value of 60 to 150 mgKOH/g.

In one embodiment, the weight ratio of the fiber and polymer resin may be 50 to 95:5 to 50.

In one embodiment, the main resin; And it may further include a reinforcing material.

The thermoplastic resin composition according to one aspect of the present invention relates to a fiber-resin masterbatch prepared by infiltrating a polymer into a fiber suspension and then dehydrating it, and a composite material containing the same, including dispersibility in the main resin of the eco-friendly fiber material, In addition to improving compatibility and processability, the mechanical properties of products obtained by molding can be improved, contributing to product productivity and economic efficiency.

The effect of one aspect of the present specification is not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration described in the detailed description or claims of the present specification.

Hereinafter, the present invention will be described. However, the present invention may be implemented in various different forms and, therefore, is not limited to the embodiments described herein.

Throughout the specification, when a part is said to be “connected” to another part, this includes not only cases where it is “directly connected,” but also cases where it is “indirectly connected” with another member in between. . Additionally, when a part is said to “include” a certain component, this does not mean that other components are excluded, but that other components can be added, unless specifically stated to the contrary.

As used herein, the term “commodity plastics” refers to plastics that have the physical properties of general plastics. As used herein, the term “thermoplastic elastomer” refers to a polymer material that has rubber-like properties, that is, elasticity, at room temperature, but is plasticized at high temperatures and can be subjected to various molding processes. For example, the thermoplastic elastomer may be one selected from the group consisting of polystyrene-based, polyolefin-based, polyurethane-based, polyester-based, vinyl chloride-based, and a combination or copolymer of two or more of these, but is not limited thereto.

As used herein, the term "engineering plastics" refers to plastics that have physical properties that can be applied to engineering materials by complementing the thermal properties and mechanical strength, which are the greatest disadvantages of general-purpose plastics. “Super-engineering plastics” refers to high-performance plastics with more improved thermal and mechanical properties than engineering plastics.

One aspect of the present invention includes the steps of mixing a fiber suspension and a polymer resin to obtain an aqueous dispersion; Obtaining a first intermediate having a moisture content of 20% by weight or less by drying the aqueous dispersion; Melting and kneading the first intermediate to obtain a second intermediate; and drying the second intermediate to obtain a third intermediate having a moisture content of 3% by weight or less.

The fiber may be a type of reinforcing material added to reinforce mechanical properties, heat resistance, etc. in a thermoplastic resin composition. The fiber includes, for example, one selected from the group consisting of glass fiber, carbon fiber, cellulose fiber, ceramic fiber and a combination of two or more thereof, preferably a cellulose fiber, more preferably a cellulose nanofiber. It may be, but is not limited to this.

Cellulose accounts for close to half of most plants and is one of the polymer substances that can be obtained in abundance from biomass. Cellulose can form hydrogen bonds through the hydroxyl group (-OH) contained in the unit structure, so it can have excellent mechanical strength and elasticity. In particular, cellulose nanofibers can be manufactured by treating cellulose dispersed in water at high pressure and applying high shear force and impact.

For example, if the fiber suspension is a suspension of cellulose fibers, cellulose nanofibers can be obtained by physicochemically treating vegetable materials such as pulp, but the method is not limited thereto.

Additionally, the fiber suspension may be modified by a chemical method, but is not limited thereto. For example, if necessary, the fiber suspension may be given desired properties through hydrophobization through treatment with a silane coupling agent.

The fiber suspension may be one in which the fibers are dispersed without being dissolved in a liquid such as water. Within the fiber suspension, the fibers may form a three-dimensional network.

The fiber suspension may satisfy at least one of the following conditions (i) to (iv): (i) solid content of 50% by weight or more; (ii) thermal decomposition temperature of 300°C or higher; (iii) contact angle greater than 110°; (iv) Inorganic content of 30% by weight or less.

If the fiber suspension satisfies at least one of the conditions (i) to (iv), it is relatively easy to manufacture a product in which the fibers are uniformly dispersed, but these conditions are not essential.

(i) at least 50% by weight, such as 50% by weight, 52.5% by weight, 55% by weight, 57.5% by weight, 60% by weight, 62.5% by weight, 65% by weight, 67.5% by weight, 70% by weight, 72.5% by weight Fiber suspensions with high solids content, such as 75% by weight, can be diluted and used without collapse of the three-dimensional network structure described above by adding water as necessary. On the other hand, when a fiber suspension with a low solid content is dehydrated to increase the solid content, the three-dimensional network structure may collapse, so it is advantageous to use a fiber suspension with a high solid content.

(ii) The thermal decomposition temperature of the fiber suspension is 300°C or higher, for example, 300°C, 305°C, 310°C, 315°C, 320°C, 325°C, 330°C, 335°C, 340°C, 345°C, 350°C. , 355°C, 360°C, 365°C, 370°C, 375°C, 380°C, 385°C, 390°C, 395°C, 400°C, etc. This thermal decomposition temperature can be measured using TGA analysis, DSC analysis, etc., and may vary depending on the composition of the fiber suspension.

(iii) The contact angle of the fiber suspension refers to the contact angle of the film made from the suspension, and may refer to the degree of hydrophobization of the fiber. When manufacturing a thermoplastic resin composition in which the hydrophobic main resin is reinforced with the above fibers, the fibers can be more easily dispersed by using a fiber suspension with a large contact angle. For example, the contact angle of the fiber suspension is 110°, 111°, 112°, 113°, 114°, 115°, 116°, 117°, 118°, 119°, 120°, 125°, 130° or It may be advantageous to have more than this, but it is not limited to this.

(iv) The mineral content of the fiber suspension may refer to the content of impurities such as titanium dioxide, calcium carbonate, and zinc oxide. For example, the inorganic content is 30% by weight or less, 27.5% by weight or less, 25% by weight or less, 22.5% by weight or less, 20% by weight or less, 17.5% by weight or less, 15% by weight or less, 12.5% by weight or less, 10% by weight or less. The values below may be advantageous for manufacturing products with uniform physical properties, but are not limited thereto.

The polymer resin may be a modified polyolefin having an acid value of 60 to 150 mgKOH/g.

The modified polyolefin may have a main chain selected from the group consisting of polyethylene, polypropylene, ethylene/α-olefin interpolymer, and a combination of two or more thereof, but is not limited thereto. The α-olefin may be, for example, one selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and combinations of two or more thereof, preferably , 1-octene, but is not limited thereto.

The modified polyolefin may be one in which an acid or an anhydride group thereof is grafted onto at least a portion of the main chain, or an acid or an anhydride group may be directly introduced into the main chain. For example, the modified polyolefin may be one selected from the group consisting of acrylic acid, maleic anhydride, styrene maleic anhydride, and a combination of two or more thereof grafted onto at least a portion of the main chain or directly introduced into the main chain, but is limited thereto. no. The anhydride group may absorb moisture and be converted to a carboxyl group to have hydrophilicity.

The acid or its anhydride group can modify or modify the essentially hydrophobic main chain of polyolefin to be hydrophilic. The hydrophilized modified polyolefin may have the necessary level of compatibility, dispersibility, and compatibility with a reinforcing material in a wet state, for example, a reinforcing material provided in a suspension, dispersion, and/or emulsion state, and the modified polyolefin and the above It can contribute to improving the processability of thermoplastic resin compositions containing reinforcing materials and the mechanical properties of molded articles manufactured therefrom.

The degree of hydrophilicity can be measured by the acid value of the polymer resin. Acid value refers to the amount of KOH required to neutralize the acid or anhydride group given to the polymer resin. A higher acid value may mean that more acid or anhydride groups are added to the polymer resin.

The acid value of the polymer resin may be 60 to 150 mgKOH/g, preferably 80 to 130 mgKOH/g, and more preferably 90 to 110 mgKOH/g, but is not limited thereto. If the acid value is excessively low, the interaction between the polymer resin and the fiber may be weakened, which may result in insufficient penetration of the polymer resin into the fiber network structure. If the acid value is excessively high, the polymer resin may penetrate into the fiber network structure due to crosslinking between the main chains. It can be difficult to do.

By mixing the fiber suspension and the polymer resin, the polymer resin can penetrate into the interior of the three-dimensional network structure formed by the fibers to form an aqueous dispersion. Even if moisture is removed through drying, this aqueous dispersion can maintain its shape and have excellent dispersibility due to the polymer resin penetrating into the network structure.

The aqueous dispersion in which the polymer resin has penetrated the fiber network structure may be dried to a moisture content of 20% by weight or less, preferably 10 to 20% by weight. In this way, moisture may be removed from the first intermediate that is primarily dried, creating an additional space for the polymer resin to penetrate. Therefore, agglomeration of fibers can be minimized through additional melt mixing.

The second intermediate after completing this melt-kneading may be secondary dried to have a moisture content of 3% by weight or less, preferably 1% by weight or less. The third intermediate material that has completed secondary drying can be molded into a form such as a pellet. This third intermediate can be applied as a fiber-resin masterbatch.

At least one of the steps of obtaining the aqueous dispersion and melt-kneading the first intermediate may be performed at 70 to 180°C, preferably at 80 to 150°C, and more preferably at 90 to 130°C. That is, at least one process of mixing the fiber suspension and the polymer resin and melt-kneading the first intermediate may be performed above the softening point of the polymer resin, preferably above the melting point. The molten polymer resin can easily penetrate into the network structure of the fiber to achieve excellent fiber dispersibility.

At least one of drying the aqueous dispersion and drying the second intermediate may be performed at 100°C or lower. This drying may be performed below the melting point of the polymer resin, preferably below the softening point. If drying is performed while the polymer resin is molten, it may be difficult to remove moisture, resulting in insufficient dehydration.

The weight ratio of fiber and polymer resin in the third intermediate may be 50-95:5-50, preferably 57.5-87.5:12.5-42.5, more preferably 65-80:20-35, but is limited to this. It doesn't work.

It may further include mixing the third intermediate with a composition containing a main resin and a reinforcing material. When the third intermediate, which is a fiber-resin masterbatch, is mixed with a composition containing the main resin and reinforcing material, the fibers are mixed while maintaining a three-dimensional network structure and can have even distribution and high dispersibility, thereby realizing an excellent reinforcing effect. You can. The composition may optionally further include additives such as impact modifiers, lubricants, and compatibilizers, as needed.

The main resin is acrylonitrile-butadiene-styrene copolymer, polyethylene, polypropylene, polyvinyl chloride, polyurethane, and ethylene vinyl acetate. It may be a general-purpose plastic selected from the group consisting of ethylene vinyl acetate, ethylene butyl acrylate, ethylene ethyl acrylate, thermoplastic elastomer, and a combination of two or more of these. , but is not limited to this.

In addition, the main resin is polycarbonate, polybutylene terephthalate, polyoxymethylene, polyamide6, polyamide66, and modified polyphenylene oxide. oxide), polyphtalamide, liquid crystal polymer, polyether ether ketone, polyimide, polyamide, and combinations of two or more of these. It may be an engineering plastic or a super engineering plastic, but is not limited thereto.

The general-purpose plastic and the engineering or super engineering plastic can be used independently of each other as the base phase of the thermoplastic resin composition, and may be mixed and used as necessary considering the use, physical properties, manufacturing cost, etc. of the final product. For example, to implement the unique properties of engineering or super engineering plastics, commercial availability is low and manufacturing costs may increase, so general-purpose plastics can be used mixed in a certain ratio.

The content of the main resin in the thermoplastic resin composition may be 30 to 95% by weight, preferably 35 to 80% by weight, and more preferably 40 to 65% by weight. When the main resin is polybutylene terephthalate and/or polyamide, if the content of the main resin in the thermoplastic resin composition is less than 30% by weight, the strength of the molded product may decrease, and if it is more than 95% by weight, hydrolysis resistance may be reduced. , chemical resistance and impact resistance may decrease.

The reinforcing material is, for example, one selected from the group consisting of talc, clay, kaolin, mica, glass fiber, carbon fiber, cellulose fiber, ceramic fiber, metal salt, silica, and a combination of two or more thereof, preferably glass fiber. , more preferably, may include flat glass fibers, but is not limited thereto.

Flat glass fibers may refer to glass fibers having a rectangular cross-section, unlike typical rod-shaped glass fibers having a circular cross-section. Flat glass fibers have stronger resistance to deformation than general glass fibers, and thus can further improve the mechanical properties of molded articles manufactured from the thermoplastic resin composition. The width of the flat glass fiber may be 1 to 50 μm, preferably 1 to 15 μm, but is not limited thereto. The length of the flat glass fiber may be 15 to 100 μm, preferably 25 to 50 μm, but is not limited thereto.

The content of the reinforcing material in the thermoplastic resin composition may be 1 to 50% by weight, preferably 10 to 30% by weight, and more preferably 15 to 25% by weight. If the content of the reinforcing material in the thermoplastic resin composition is less than 1% by weight, the effect of improving the mechanical properties and heat resistance of the molded body manufactured from the thermoplastic resin composition is weak, and if it is more than 50% by weight, the flowability and resulting dispersibility of the thermoplastic resin composition are reduced. , processability, and impact resistance of molded articles manufactured from the thermoplastic resin composition may be reduced.

The content of the third intermediate in the thermoplastic resin composition may be 1 to 50% by weight, preferably 10 to 45% by weight, and more preferably 20 to 40% by weight. If the content of the third intermediate in the thermoplastic resin composition is less than 1% by weight, the effect of improving the mechanical properties and heat resistance of the molded body manufactured from the thermoplastic resin composition is weak, and if it is more than 50% by weight, the flowability of the thermoplastic resin composition and the resulting Dispersibility, processability, and impact resistance of molded articles manufactured from the thermoplastic resin composition may be reduced.

The total content of each additive in the thermoplastic resin composition may be 0 to 10% by weight, preferably 0.1 to 5% by weight, and more preferably 0.25 to 2.5% by weight. If the content of the additive exceeds 10% by weight, the content of the main component of the thermoplastic resin composition decreases, making it difficult for the final product to meet the required physical properties.

Another aspect of the present invention is a fiber forming a three-dimensional network structure; and a continuous polymer resin matrix permeating the network structure. The thermoplastic resin composition includes a water content of 3% by weight or less.

The thermoplastic resin composition is the same as that described for the above-described fiber-resin masterbatch, i.e., the third intermediate.

That is, the fibers forming the three-dimensional network structure may be dried in a form in which a polymer resin has penetrated the fiber suspension.

The polymer resin may be a modified polyolefin having an acid value of 60 to 150 mgKOH/g, as described above.

Additionally, the weight ratio of the fiber and polymer resin may be 50 to 95:5 to 50, as described above.

The thermoplastic resin composition includes a main resin; and reinforcing materials; and, optionally, additives such as impact modifiers, lubricants, and compatibilizers. The characteristics and contents of each of these are as described above.

In other words, the thermoplastic resin composition further comprising a main resin and a reinforcing material may mean a composite material obtained by diluting (let-down) the fiber-resin masterbatch described above.

Hereinafter, embodiments of the present specification will be described in more detail. However, the following experimental results describe only representative experimental results among the above examples, and the scope and content of the present specification cannot be interpreted as being reduced or limited by the examples. Each effect of various implementations of the present specification that are not explicitly presented below will be described in detail in the corresponding section.

Examples and Comparative Examples

Waxes (wax 1, wax 2) made of polyolefin elastomer (ethylene-octene random copolymer polymerized by a metallocene catalyst) were prepared.

1,600 to 1,980 g of wax 1 was cooled to 155°C, and then 2 to 40 g of dicumyl peroxide and 20 to 400 g of functional monomer (acrylic acid, AA) were charged into the reactor using a nozzle provided at the top of the reactor. Wax 1-1 to 1-4 in which acrylic acid is grafted onto the main chain of the polymer constituting wax 1 is continuously added to the surface of wax 1 at a constant rate for 30 to 120 minutes and reacted for 30 to 120 minutes while maintaining the temperature. got it Waxes 1-5 to 1-8, in which maleic anhydride was grafted onto the main chain of the polymer constituting wax 1, were obtained in the same manner, except that maleic anhydride (MAH) was used instead of acrylic acid as the functional monomer. The higher the content of functional monomer and the longer the reaction time, the higher the acid value of the graft wax.

Meanwhile, 1,900 g of wax 2 was cooled to 155°C, and then 10 g of dicumyl peroxide and 100 g of maleic anhydride (MAH) were added to the surface of wax 2 filled in the reactor using a nozzle provided at the top of the reactor. It was continuously added at a constant rate for 60 minutes and reacted for 60 minutes while maintaining the temperature to obtain wax 2-1 in which maleic anhydride was grafted onto the main chain of the polymer constituting wax 2. 1,900 g of wax 2-1 was cooled to 155°C, and then 10 g of dicumyl peroxide and 100 g of 4-amino-2,2,6,6-tetramethylpiperidine were added to the reactor through a nozzle provided at the top of the reactor. was continuously added to the surface of the wax 2-1 filled in the reactor at a constant rate for 60 minutes and reacted for 60 minutes while maintaining the temperature to produce 4-amino-2,2,6,6-tetramethylp in maleic anhydride. Peridine-grafted wax 2-2 was obtained.

Each physical property measured according to the following method is shown in Table 1 below.

-Viscosity (cps, @177℃): Brookfield viscometry, Spindle No. 31

-Acid value (mgKOH/g): Based on ASTM D1386-98, the amount of KOH required to neutralize the carboxyl group grafted on 1g of wax was measured in mg and used as the acid value.

division viscosity
(cps) density
(g/ml) melting point
(℃) functional monomer Sanga
(mgKOH/g) wax 1 1,000 0.8815 74 - 0 wax 1-1 830 0.8803 76 AA 13 wax 1-2 720 0.8786 74 AA 40 Wax 1-3 580 0.8771 80 AA 100 Wax 1-4 610 0.8772 81 AA 130 Wax 1-5 780 0.879 75 M.A.H. 23 Wax 1-6 690 0.8782 76 M.A.H. 45 Wax 1-7 670 0.8776 78 M.A.H. 65 Wax 1-8 620 0.8768 80 M.A.H. 110 wax 2 9,000 0.8853 77 - - Wax 2-1 8,600 0.8842 72 M.A.H. - wax 2-2 7,500 0.8815 68 M.A.H. -

An aqueous dispersion was prepared by mixing 70 parts by weight of the fibrous cellulose suspension and 30 parts by weight of one of the waxes 1 to 1-8. The prepared aqueous dispersion was first dried at 99°C to have a moisture content of 20% by weight or less, and then melt-kneaded at 150°C. A fiber-resin masterbatch was prepared by secondary drying at 99°C to a moisture content of 1% by weight or less and then molding.

Polybutylene terephthalate (PBT), flat glass fiber (FF, width 7㎛, length 28㎛), fiber-resin masterbatch (CNF-MB), and wax 2-2 (additive) are melted and kneaded to create thermoplastic resin. The composition was obtained, and a molded specimen was manufactured by extruding it. The composition of the thermoplastic resin composition is shown in Table 2 below.

When 20 parts by weight of cellulose nanofiber powder and 10 parts by weight of wax 1-4 were applied directly instead of the fiber-resin masterbatch, the cellulose nanofibers agglomerated and a specimen could not be manufactured.

division PBT FF CNF-MB wax type additive Comparative Example 1 79.5 20 - - 0.5 Comparative Example 2 50 20 29.5 wax 1 0.5 Comparative Example 3 50 20 29.5 wax 1-1 0.5 Comparative Example 4 50 20 29.5 wax 1-2 0.5 Example 1 50 20 29.5 Wax 1-3 0.5 Example 2 50 20 29.5 Wax 1-4 0.5 Comparative Example 5 50 20 29.5 Wax 1-5 0.5 Comparative Example 6 50 20 29.5 Wax 1-6 0.5 Example 3 50 20 29.5 Wax 1-7 0.5 Example 4 50 20 29.5 Wax 1-8 0.5

(Unit: weight%)

Experimental Example 1

The melt index (g/10min, @230°C, 2.16kg, KS M ISO 1133-1:2017) for each thermoplastic resin composition obtained in Examples and Comparative Examples was measured, and the results are shown in Table 3 below. .

division melt index Comparative Example 1 11.4 Comparative Example 2 2.5 Comparative Example 3 2.6 Comparative Example 4 2.3 Example 1 13.7 Example 2 5.3 Comparative Example 5 2.5 Comparative Example 6 2.6 Example 3 5.7 Example 4 11.3

Referring to Table 3, Comparative Examples 2 to 6 including cellulose fibers as reinforcing materials had a low melt index and were relatively poor in processability. On the other hand, Examples 1 to 4, in which waxes 1-3, 1-4, 1-7, and 1-8 with an acid value of 65 to 130 mgKOH/g were applied as the resin constituting the continuous matrix of the fiber-resin masterbatch, were relatively melted. The index increased. Among them, Examples 1 and 4 were shown to have a melt index similar to or higher than Comparative Example 1, which does not contain cellulose fibers, and the acid value of the matrix resin constituting the masterbatch is one of the factors determining the dispersibility of cellulose nanofibers. It was confirmed that it was one.

Experimental Example 2

The mechanical properties of each molded body obtained in Examples and Comparative Examples were measured, and the results are shown in Table 4 below.

-Tensile strength: According to ASTM D638, the specimen was measured at 25°C by pulling at a speed of 5 mm/min using a universal testing machine.

-Flexural strength and flexural modulus: Based on ASTM D790, the specimen was measured at 25°C by stretching a 50mm gap at a speed of 4mm/min using a universal testing machine.

-Impact strength: Based on ASTM D256, it was measured by applying an impact load of 60kg to a specimen with a width of 1/4 inch at 25°C using an Izod-type impact test equipment.

division tensile strength
(MPa) Flexural strength
(MPa) Flexural modulus of elasticity
(GPa) impact strength
(1/4", J/m) Comparative Example 1 88 134.1 4.35 52.3 Comparative Example 2 67.9 108.5 4.79 56.7 Comparative Example 3 68.3 109.7 4.84 63.1 Comparative Example 4 62.2 93.1 4.86 47.3 Example 1 81.2 120.8 4.82 66.3 Example 2 71.4 111.6 5.03 60.0 Comparative Example 5 64.8 99.8 4.85 59.7 Comparative Example 6 61.3 91.7 4.83 48.2 Example 3 71.3 113.3 4.81 60.2 Example 4 74.4 115.9 5.04 63.7

Referring to Table 4 above, Examples 1 to 4 in which cellulose fibers were applied as a reinforcing material were shown to have excellent impact strength. Using a fiber-resin masterbatch made with a matrix resin with the acid value of the matrix resin adjusted, the cellulose nanofibers were improved. It can be confirmed that the distributed structure can be maintained stably.

In a wet cellulose suspension, cellulose nanofibers form a kind of three-dimensional network structure. In cellulose nanofiber powder obtained directly from a cellulose suspension through a dehydration process, the network structure was destroyed, resulting in insufficient dispersibility when applied as a reinforcing material. On the other hand, in the fiber-resin masterbatches of Examples 1 to 4, in which a polymer resin with an adjusted acid value was infiltrated into the three-dimensional network structure of the cellulose suspension and then dehydrated, the dispersibility of the cellulose nanofibers was excellent while the three-dimensional fibrous network structure was preserved. Excellent reinforcement effect was achieved.

The description of the present specification described above is for illustrative purposes, and a person skilled in the art to which an aspect of the present specification pertains can easily transform it into another specific form without changing the technical idea or essential features described in the present specification. You will be able to understand it. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. For example, each component described as unitary may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form.

The scope of the present specification is indicated by the claims, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present specification.

Claims (10)

Obtaining an aqueous dispersion by mixing a fiber suspension and a polymer resin;
Obtaining a first intermediate having a moisture content of 20% by weight or less by drying the aqueous dispersion;
Obtaining a second intermediate by melting and kneading the first intermediate; and
Comprising: drying the second intermediate to obtain a third intermediate having a moisture content of 3% by weight or less,
The fiber is a cellulose nanofiber,
The solid content of the fiber suspension is 50% by weight or more,
A method for producing a thermoplastic resin composition, wherein the polymer resin is a modified polyolefin having an acid value of 60 to 150 mgKOH/g. According to paragraph 1,
A method for producing a thermoplastic resin composition, wherein the fiber suspension satisfies at least one of the following conditions (ii) to (iv):
(ii) thermal decomposition temperature of 300°C or higher;
(iii) contact angle greater than 110°;
(iv) Inorganic content of 30% by weight or less. delete According to paragraph 1,
At least one of the steps of obtaining the aqueous dispersion and melt-kneading the first intermediate is performed at 70 to 180°C. According to paragraph 1,
A method for producing a thermoplastic resin composition, wherein at least one of drying the aqueous dispersion and drying the second intermediate is performed at 100° C. or lower. According to paragraph 1,
A method for producing a thermoplastic resin composition, further comprising mixing the third intermediate with a composition containing a main resin and a reinforcing material. It is manufactured using the method for producing a thermoplastic resin composition according to any one of claims 1, 2, and 4 to 6,
Fibers forming a three-dimensional network structure; and
It includes a continuous polymer resin matrix that has penetrated into the network structure,
The moisture content is less than 3% by weight,
The fiber is a cellulose nanofiber,
A thermoplastic resin composition wherein the polymer resin is a modified polyolefin having an acid value of 60 to 150 mgKOH/g. delete In clause 7,
A thermoplastic resin composition wherein the weight ratio of the fiber and polymer resin is 50 to 95:5 to 50. delete