Biological filler for resin reinforcement and resin composition comprising same

Abstract

The present invention provides a resin reinforcing material, a method for manufacturing the same, a resin composition comprising the same, and a composite manufactured from the resin composition, the resin reinforcing material comprising a plant-derived biological filler and a latex coating layer formed on the surface of the biological filler, the latex coating layer comprising a conjugated diene rubber containing a carboxyl group.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0114178, filed on August 26, 2024, the entire contents of which are incorporated herein by reference as part of the specification. Technical Field

[0003] The present invention relates to bio-fillers for resin reinforcement and resin compositions comprising the bio-fillers, and more particularly, to bio-fillers whose moisture resistance and physical properties are improved by surface modification and resin compositions comprising the bio-fillers as reinforcing materials. Background Technology

[0004] Recently, the manufacture of composite materials, which utilize environmentally friendly materials as reinforcing materials to improve the physical properties of polymer resins, is increasing in various fields such as packaging materials, molded products, and various industrial materials.

[0005] For example, in the case of building materials and everyday consumer goods, composite materials are being developed that disperse wood flour in thermoplastic resins such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), acrylonitrile-butadiene-styrene (ABS), polyethylene terephthalate (PET), polylactic acid (PLA), and polybutylene terephthalate (PBAT) and then extruded; these are known as biocomposite materials. In addition to the processability, low cost, and high surface strength of polymer resins, biocomposite materials offer various advantages, including environmental friendliness due to the use of plant-derived wood flour, improved hardness (a drawback of polymer resins), and the ability to impart unique wood grain textures. These biocomposite materials are also used in automotive interior and exterior materials and household appliances.

[0006] In addition, cellulose fiber composites have been used to achieve lightweighting and improved recyclability, replacing the high-density inorganic reinforcement materials that were previously used in other molded products.

[0007] Meanwhile, plant-derived biofillers used in the manufacture of environmentally friendly composite materials, such as wood flour and cellulose fibers, exhibit hydrophilicity due to the hydroxyl groups present on their surfaces and are easily affected by moisture. Therefore, when moisture permeates into products using biofillers, swelling or dissolution occurs, causing dimensional changes. The low compatibility of biofillers with hydrophobic polymer resins due to their hydrophilicity reduces the interfacial bonding between heterogeneous materials, leading to deterioration of physical properties. Furthermore, because biofillers are formed from highly crystalline polymers, they are rigid and easily broken, resulting in insufficient impact resistance.

[0008] Therefore, it is possible to use the biological filler used in the resin composition for manufacturing the composite as much as possible to dry it to adjust the moisture content, or to use compatibilizers to improve the bonding force between the biological filler and the polymer resin, additives to improve the impact resistance, etc., but there are limitations in overcoming the moisture resistance and impact resistance of the biological filler. Summary of the Invention

[0009] Technical issues

[0010] The present invention aims to provide a biological filler with improved physical properties such as moisture resistance and impact resistance through surface modification, a method for manufacturing the same, and a resin composition and composite containing the biological filler as a reinforcing material.

[0011] Technical solution

[0012] In one general aspect, the resin-reinforced material comprises: a plant-derived biofiller and a latex coating formed on the surface of the biofiller, wherein the latex coating comprises a carboxyl-containing conjugated diene rubber.

[0013] In another general aspect, the method for manufacturing the resin-reinforced material includes: (S1) adding a biofiller to a high-speed mixer and stirring it while spraying a latex coating liquid to form a latex coating layer on the surface of the biofiller; and (S2) drying and then compressing the biofiller on which the latex coating has been formed.

[0014] In another general aspect, a resin composition is provided comprising a polymer resin and a resin reinforcing material comprising a biofiller having a latex coating formed thereon, and a composition produced by extrusion molding of the composition.

[0015] Beneficial effects

[0016] According to the present invention, the moisture resistance of the biological filler can be overcome by forming a latex coating on the surface of the biological filler used as a resin reinforcing material, thereby allowing the hydroxyl groups present on the surface of the biological filler to bond with the carboxyl groups of the latex rubber through chemical modification.

[0017] Furthermore, when latex-coated biofillers are mixed with polymer resins to form a composite, the latex coating acts as an adhesive to increase the compatibility between the biofillers and the polymer resins, thereby improving the interfacial adhesion strength.

[0018] Furthermore, by compressing the latex-coated biofiller, physical surface modification can be used to remove the micropores inside the biofiller to improve its physical properties. Additionally, the biofiller powder can be granulated to adjust the particle size to various dimensions, thereby maximizing the ease of manufacturing and design effectiveness. Attached Figure Description

[0019] Figure 1 The particle shape of the biofiller contained in the resin-reinforced material according to an exemplary embodiment is schematically shown.

[0020] Figure 2 The high-temperature compression of latex-coated biofiller is shown in a method for manufacturing a resin-reinforced material according to an exemplary embodiment of the present invention.

[0021] Figure 3 The SEM-EDS analysis results before and after surface modification of the bio-filler are shown.

[0022] Figure 4 Sheet samples of the composite materials prepared in the examples and comparative examples are shown.

[0023] Figure 5 The illustration schematically shows a coating formed by a chemical reaction with hydroxyl groups present on the surface of a biofiller, according to an exemplary embodiment of the invention. Detailed Implementation

[0024] The terms and words used in this specification and claims should not be interpreted in their general or dictionary sense, but rather should be interpreted as meanings and concepts consistent with the technical ideas of the invention, based on the principle that inventors can appropriately define the concepts of terms in order to best describe their own inventions.

[0025] Furthermore, the structures shown in the embodiments described in the specification and drawings are merely the most preferred examples of the present invention and do not represent the entire technical concept of the present invention. Therefore, it should be understood that various equivalents and modifications that can replace the above structures are possible.

[0026] In this application, each of the phrases such as “A or B”, “at least one of A and B”, “at least one of A or B”, “A, B or C”, “at least one of A, B and C” and “at least one of A, B or C” may include any item listed together with the corresponding phrase of the phrase or all possible combinations thereof.

[0027] In this application, the term "and / or" includes a combination of the plurality of related components described or any one of the plurality of related components described.

[0028] In this application, unless explicitly stated otherwise, the word “comprising” or “containing” any component shall be understood to imply the inclusion of other elements rather than the exclusion of any other elements.

[0029] An exemplary embodiment of the present invention relates to a resin-reinforced material comprising a plant-derived biofiller and a latex coating formed on the surface of the biofiller.

[0030] In the resin-reinforced material according to the invention, the biofiller may include one or more of the following: wood flour from pine, spruce, acacia and rubber trees as tree types; kenaf, flax, hemp, jute and bamboo seeds as annual or perennial plants; wheat and barley as cereals; coconut shells and coffee grounds as shells obtained as food processing by-products; and cellulose and lignocellulose as natural fiber types.

[0031] Specifically, wood flour is a powder made by grinding wood into small particles and then drying them.

[0032] Cellulose can be produced from wood pulp, which is an aggregate of fibers having one primary wall and multiple secondary walls. For example, microfibrillated cellulose powder can be used, obtained by dispersing the fiber aggregate in water and applying shear force to defibrillate and then drying to remove water.

[0033] The biofiller exhibits hydrophilicity through the hydroxyl groups present on its surface and forms aggregates by forming hydrogen bonds between particles through the hydroxyl groups. Therefore, the biofiller used in this invention can be in powder form comprising primary particles and secondary particles formed by agglomerating one or more primary particles through hydroxyl groups.

[0034] Biological fillers in powder form can be used by grading them into particles of a certain size using a sieve. For example, the biological filler powder suitable for use in this invention may include primary particles with an average size of 10 μm to 250 μm or 30 μm to 150 μm and secondary particles with an average size of 100 μm to 2500 μm or 100 μm to 2000 μm, which are formed by the aggregation of one or more primary particles.

[0035] In the resin-reinforced material of the present invention, the latex coating comprises a carboxyl-containing conjugated diene rubber, which can be formed on the surface of the primary particles of the biofiller and on the surface of the secondary particles formed by the aggregation of one or more of the primary particles.

[0036] Specifically, the carboxyl-containing conjugated diene rubber included in the latex coating may include one or more of the following: acrylonitrile butadiene rubber (a1) containing carboxyl groups, styrene-butadiene rubber (SBR) containing carboxyl groups (a2), and conjugated diene rubber containing carboxyl groups (a3).

[0037] Carboxyl-containing nitrile rubber (a1) can be manufactured by copolymerization of conjugated diene monomers, olefinically unsaturated carboxylic acid monomers and olefinically unsaturated nitrile monomers.

[0038] Examples of conjugated diene monomers may include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, chloroprene, etc., and the conjugated diene monomer unit may be included in 50% to 80% or 55% to 70% by weight based on the total weight of the carboxyl-containing acrylonitrile rubber.

[0039] Examples of olefinically unsaturated carboxylic acid monomers may include acrylic acid, methacrylic acid, etc. The content of the olefinically unsaturated carboxylic acid monomer unit relative to the total weight of the carboxyl-containing acrylonitrile rubber may be from 2% to 10% by weight or from 2% to 6% by weight, and the content may vary depending on the physical properties required in the art.

[0040] Examples of olefinically unsaturated nitrile monomers may include acrylonitrile, methacrylonitrile, fumaric acid, α-chloroacrylonitrile, α-cyanoethylacrylonitrile, etc. Based on the total weight of the carboxyl-containing nitrile butadiene rubber, the olefinically unsaturated nitrile monomer unit may be included in 10% to 40% by weight or 20% to 40% by weight, and the content may vary depending on the physical properties required in the art.

[0041] In addition, carboxyl-containing nitrile rubber may further contain other olefinic unsaturated monomers (e.g., amide-containing monomers, epoxy-containing monomers, etc.) that can copolymerize with the monomer.

[0042] Alternatively, carboxyl-containing styrene-butadiene rubber (a2) can be manufactured by copolymerizing conjugated diene monomers such as 1,3-butadiene, olefinically unsaturated carboxylic acid monomers, and styrene. Furthermore, it may further contain other olefinically unsaturated monomers that can copolymerize with these monomers. The monomer content can be appropriately selected according to the physical properties required in the art.

[0043] Carboxyl-containing conjugated diene rubber (a3) ​​can be manufactured by copolymerizing conjugated diene monomers and olefinically unsaturated carboxylic acid monomers, and may further contain other olefinically unsaturated monomers that can be copolymerized with these monomers. The monomer content can be appropriately selected according to the physical properties required in the art.

[0044] Because the latex of the rubber component has carboxyl groups, therefore... Figure 5 As shown, it can form a coating by forming ester bonds with hydroxyl groups present on the surface of the biological filler through a chemical reaction.

[0045] When the surface of a biofiller is chemically modified through ester bonds with the latex itself of the rubber component, a latex coating formed on the surface of the biofiller can impart moisture barrier properties. Therefore, products using latex-coated biofillers exhibit reduced moisture permeability and suppress dimensional changes such as swelling or dissipation even in contact with moisture.

[0046] Furthermore, when biofillers are mixed with polymer resins to form a composite, the latex coating acts as a binder, thereby increasing the compatibility between the biofillers and polymer resins to improve interfacial adhesion strength, and thus improving the physical properties of products using biofillers.

[0047] Furthermore, as the particle size of the biofiller increases through the formation of the latex coating, products with biofiller applied as a reinforcing material exhibit improved shock absorption when subjected to impact and can demonstrate excellent impact strength.

[0048] In one exemplary embodiment of the present invention, the latex coating can be formed as a thin film surrounding primary or secondary particles of the biofiller by a spraying method. For example, the latex coating can be formed with a thickness of 0.2 μm to 50 μm or 0.25 μm to 40 μm. If the coating thickness is less than 0.2 μm, it is difficult to improve the moisture barrier properties and compatibility with the polymer resin of the biofiller. If it exceeds 50 μm, the dispersibility of the coating liquid is reduced, leading to deterioration of physical properties.

[0049] The particle size of latex-coated biofillers can range from 0.1 mm to 10 mm or from 1 mm to 10 mm. When the average particle size of latex-coated biofillers is less than 0.1 mm, their effect on improving the impact strength as a reinforcing material is sometimes insufficient; when the average particle size is greater than 10 mm, they are sometimes difficult to disperse uniformly when included in the composite.

[0050] Depending on the requirements, the resin-reinforced material may further include additives such as crosslinking agents, dispersants, stabilizers, thickeners, lubricants, and antioxidants to improve physical properties. The content of these additives can be appropriately selected within a range that does not impair the inherent properties of the resin-reinforced material.

[0051] Another exemplary embodiment of the present invention relates to a method for manufacturing a resin-reinforced material, the method comprising: (S1) adding a biofiller to a high-speed mixer and stirring it while spraying a latex coating liquid to form a latex coating on the surface of the biofiller; and (S2) drying and then compressing the biofiller on which the latex coating is formed.

[0052] In (S1), the biofiller may include one or more of the following: wood powder from pine, spruce, acacia or rubber trees; plants such as kenaf, flax, hemp, jute or bamboo seeds; grains such as wheat or barley; husks such as coconut shells or coffee grounds; and natural fibers such as cellulose or lignocellulose, and specifically, the powder, which is dried and ground into small particles, may have a moisture content of less than 10%.

[0053] In an exemplary embodiment of the present invention, the biofiller powder may be formed from particles of 10 to 500 mesh, 10 to 200 mesh or 10 to 60 mesh, for example, it may be formed from primary particles having an average size of 10 μm to 250 μm or 30 μm to 150 μm and secondary particles having an average size of 100 μm to 2500 μm or 100 μm to 2000 μm (which are formed by the aggregation of one or more primary particles).

[0054] Meanwhile, the latex coating solution can be prepared by dispersing the carboxyl-containing conjugated diene rubber described above in water.

[0055] Here, based on the weight of the biofiller, carboxyl-containing conjugated diene rubber can be used in amounts from 0.5% to 30% by weight or from 10% to 30% by weight. When the content of carboxyl-containing conjugated diene rubber is less than 0.5% by weight, the effect of imparting moisture barrier properties to the biofiller and improving compatibility with polymer resins is not significant; when it exceeds 30% by weight, there are difficulties in dispersion and the physical properties deteriorate due to the increase in rubber content.

[0056] Depending on the requirements, the latex coating liquid may further include crosslinking agents, dispersants, stabilizers, thickeners, etc.

[0057] Latex coating solutions can be applied to the surface of biofillers by spraying the solution using a spraying device. Specifically, coating can be achieved by adding the biofiller to a high-speed mixer and stirring it, while simultaneously spraying the latex coating solution through the nozzle of the spraying device and holding it for a certain period of time (e.g., 1 to 5 minutes or 2 to 3 minutes) to allow a chemical reaction to occur between the biofiller and the latex.

[0058] Spray coating involves uniformly spraying a latex coating solution onto the surface of the biofiller, forming a thin film that surrounds the surface of the biofiller particles. Furthermore, as the particle size of the biofiller increases through the formation of the latex coating, the impact strength when applied to a product can be improved.

[0059] In an exemplary embodiment of the present invention, for stable operation of the high-speed mixer, stirring can be performed at a speed of 500 rpm to 1500 rpm or 800 rpm to 1200 rpm.

[0060] In (S2), the biofiller with a latex coating is dried to remove moisture, and then it can be compressed by adding it to a compression device such as a pressing jig and pressing it at a high temperature.

[0061] Drying can be carried out at 50°C to 120°C or 70°C to 90°C for 2 to 5 hours or 3 to 4 hours.

[0062] High-temperature compression can be performed using compression equipment such as presses, roller mills, or granulators, and physical surface modification can be achieved by applying physical forces to the surface of the biofiller in the chemically bonded state of the latex to obtain chain anchoring. Without compression after latex coating, agglomeration occurs in the coating layer, making it difficult to increase particle size through coating.

[0063] Furthermore, the micropores inside the biofiller are removed by high-temperature compression to increase the packing density. Therefore, when forming a complex with a polymer resin, a high content of biofiller can be used, which can promote the improvement of physical properties.

[0064] Furthermore, high-temperature compression allows for the granulation of biological filler powder, and the particle size can be adjusted to various sizes, thus maximizing process convenience and design effectiveness in product manufacturing.

[0065] In an exemplary embodiment of the invention, compression can be performed for 1 to 5 minutes or 2 to 4 minutes at 70°C to 250°C or 100°C to 230°C and 10 to 70 bar or 10 to 50 bar. When the pressure during compression is less than 5 bar, it may be difficult to implement the desired physical surface modification in the biofiller, and when the pressure is greater than 70 bar, it may lead to carbonization of the latex and the biofiller.

[0066] Biofillers with latex coatings produced by the method described above can be used as resin reinforcing materials in conjunction with polymer resins.

[0067] Therefore, another exemplary embodiment of the present invention relates to a resin composition comprising: a polymer resin and a resin reinforcing material, wherein the resin reinforcing material comprises a biofiller having a latex coating formed on the biofiller.

[0068] The polymer resin may include one or more selected from the following: thermoplastic resins, including polylactic acid (PLA), polybutylene adipate (PBAT), polyethylene (PE), polypropylene (PP), acrylonitrile-butadiene-styrene (ABS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), or mixtures thereof; and thermosetting resins, including epoxy resins, amino resins, phenolic resins, polyester resins, polyurethane resins, or mixtures thereof.

[0069] Polymer resins are used in the manufacture of various molded products due to their processability, low price, and high surface strength. From an environmentally friendly perspective, the use of bio-fillers as resin reinforcement materials is increasing. However, due to the moisture resistance of bio-fillers, when exposed to high temperature and humid environments, they may exhibit dimensional deformation, poor compatibility with hydrophobic polymers, and low impact resistance, leading to deterioration of mechanical properties.

[0070] To overcome these drawbacks, in this invention, a biofiller with a latex coating is used as a reinforcing material to form a composite with a polymer resin. Since the biofiller is surface-modified with latex, it can have improved compatibility and bonding strength with the hydrophobic polymer resin, as well as improved impact resistance, thereby improving the physical properties of the composite.

[0071] In the resin composition according to an exemplary embodiment of the present invention, the bio-filler on which the latex coating is formed may be included in an amount of 1% to 40% by weight or 5% to 20% by weight, based on the total weight of the composition. When the content of the bio-filler is less than 1% by weight, it is difficult to fully exert its function as a reinforcing material, and when the content is greater than 40% by weight, the article is sometimes difficult to mold due to reduced fluidity.

[0072] Depending on the requirements, the resin composition may contain commonly used additives in the art, such as compatibilizers, antioxidants, lubricants, and pigments, and their contents may be appropriately selected within the range required to achieve the desired physical properties.

[0073] Resin compositions are made into composites by methods such as extrusion or injection molding, and can be used in various applications such as packaging materials, building materials, automotive interior and exterior materials, and home appliances.

[0074] The present invention will be described in detail below through the following embodiments in order to provide an understanding of the invention. However, embodiments of the present invention can be modified in many other different forms, and the scope of the invention should not be construed as limited to the following embodiments. The embodiments of the invention are provided to explain the invention more completely to those skilled in the art.

[0075] Manufacturing example: Manufacturing of resin-reinforced materials

[0076] Manufacturing Example 1

[0077] Step 1

[0078] Pine wood powder, which passed through a 60-mesh sieve, was prepared as a biological filler and dried in an oven at 80°C for approximately 24 hours. 120g of the dried pine wood powder was added to a high-speed mixer, and the mixer was operated with a stirring speed slowly increased to 1000 rpm.

[0079] Simultaneously, 90g of a latex coating solution in which acrylonitrile rubber (NBR) was dispersed in water was prepared and sprayed into a running high-speed mixer using a spraying device. At this point, 10% by weight of NBR was used based on the weight of the biofiller. The high-speed mixer was then operated for 3 minutes to achieve uniform mixing and obtain a biofiller powder with a surface modified by forming an NBR latex coating.

[0080] Step 2

[0081] The NBR latex-coated biofiller powder was dried in an oven at 80°C for approximately 3 hours to remove moisture. 30g of the dried powder was weighed and added to a pressing fixture, such as... Figure 2 As shown, the material was pressed for 3 minutes at 200°C and 10 bar. This resulted in the preparation of a surface-modified bio-filler via latex coating and compression as a resin reinforcing material.

[0082] Figure 3 The SEM-EDS results of the biofiller (a) before surface modification and the biofiller (b) after surface modification, as shown in Manufacturing Example 1, are presented.

[0083] Depend on Figure 3 It was confirmed that the surface-modified biofiller (b) had a larger particle size compared to the unmodified biofiller (a) due to the formation of the NBR latex coating.

[0084] Manufacturing Example 2

[0085] Except for the compression in step 2 at 50 bar, the resin-reinforced material is manufactured in the same manner as in manufacturing example 1.

[0086] Manufacturing Example 3

[0087] Except that NBR of 30% by weight relative to the biofiller is used in step 1 and the material is compressed at 50 bar in step 2, the resin-reinforced material is manufactured in the same manner as in manufacturing example 1.

[0088] Comparative Manufacturing Example 1

[0089] Except for not performing the compression in step 2, the resin-reinforced material of the bio-filler powder that has undergone chemical surface modification by forming an NBR latex coating is manufactured in the same manner as in manufacturing example 1.

[0090] Comparative Manufacturing Example 2

[0091] Pine wood powder, sieved through a 60-mesh sieve, was prepared as a biological filler and dried in an oven at 80°C for approximately 24 hours. 30g of the dried powder was weighed and added to a pressing fixture, as shown. Figure 2 As shown, the material was pressed for 3 minutes at 200°C and 50 bar. This resulted in a resin-reinforced material made from bio-filler powder with only surface physical modification.

[0092] Example: Preparation of a resin composition containing a resin reinforcing material

[0093] Example 1

[0094] A resin composition was obtained by mixing 90% by weight of a polymer resin, which is a mixture of polylactic acid (PLA) and polybutylene adipate (PBAT) in a 1:1 weight ratio, with 10% by weight of the resin reinforcing material of Example 1.

[0095] The resin composition was added to a twin-screw extruder and extruded at 170°C, 250 rpm, and 15 kg / hr to produce a compound in granular form.

[0096] Example 2

[0097] The granular composite was prepared in the same manner as in Example 1, except that the PLA / PBAT (1:1) polymer resin was mixed with the resin reinforcing material of Manufacturing Example 2.

[0098] Example 3

[0099] The granular composite was prepared in the same manner as in Example 1, except that the PLA / PBAT (1:1) polymer resin was mixed with the resin reinforcing material of Manufacturing Example 3.

[0100] Comparative Example 1

[0101] The granular composite was prepared in the same manner as in Example 1, except that the PLA / PBAT (1:1) polymer resin was mixed with unmodified biofiller (60-mesh pine powder) as a resin reinforcing material.

[0102] Comparative Example 2

[0103] The granular composite was prepared in the same manner as in Example 1, except that the PLA / PBAT (1:1) polymer resin was mixed with the resin reinforcement material of Comparative Manufacturing Example 1.

[0104] Comparative Example 3

[0105] The granular composite was prepared in the same manner as in Example 1, except that the PLA / PBAT (1:1) polymer resin was mixed with the resin reinforcement material of Comparative Manufacturing Example 2.

[0106] Experimental Example: Evaluation of Physical Properties

[0107] Moisture absorption rate

[0108] After exposing each bio-filler used as a resin reinforcing material in the examples and comparative examples to 40°C and 95% relative humidity for 8 hours, the rate of change of initial weight (W1) and post-exposure weight (W2) was measured, and the moisture absorption rate was evaluated according to the following formula: Moisture absorption rate (%) = (W2 - W1) / W1 × 100 Melt Flow Index The melt flow index (MI) of the composite materials prepared in the examples and comparative examples was measured at 190°C using 2.16 kg weight, according to ASTM D1238.

[0109] Mechanical properties

[0110] Samples with thicknesses of 3.2 mm and 6.4 mm were manufactured from the composite materials produced in the Examples and Comparative Examples using a hot press, and the IZOD impact strength of each sample was measured according to ASTM D256.

[0111] [Table 1]

[0112] Table 1 confirms that the biofillers of Examples 1 to 3, chemically and physically surface-modified by latex coating and compression, exhibit reduced moisture absorption to improve moisture resistance, and that the composites using them as resin reinforcement materials possess high melt index and improved IZOD impact strength. Specifically, Example 3, with an increased latex coating amount of up to 30% by weight during chemical surface modification, exhibits the best IZOD impact strength. This result is expected to be due to the increased melt index resulting from the increased compatibility between the biofiller and the polymer resin through latex coating, thus improving bonding strength, and the increased impact strength due to the increased particle size.

[0113] However, in Comparative Example 1, the moisture absorption rate increased because the biofiller was not surface modified, resulting in low melt index and IZOD impact strength of the composite material using the biofiller.

[0114] In Comparative Example 2, since only chemical surface modification of the latex coating based on bio-filler was performed, the improvement in moisture absorption was not significant. Compared with Example 1, the composite material using bio-filler had the same melt index but a reduced IZOD impact strength.

[0115] In Comparative Example 3, since only the biofiller underwent physical surface modification by compression, the moisture absorption rate increased, and the composite material using the biofiller had a lower melt index and similar IZOD impact strength compared to Example 2.

[0116] also, Figure 4Sheet samples of composite materials manufactured in the Examples and Comparative Examples are shown. Sample (#1) is a composite of Comparative Example 1 using a biofiller that has not been surface-modified with the resin reinforcing material, exhibiting a wood flour color appearance. Sample (#2) is a composite of Comparative Example 2 using a biofiller that has only undergone chemical surface modification, resulting in a darker wood flour color when coated with NBR, but due to insufficient particle size adjustment after coating without compression, it exhibits an appearance similar to Comparative Example 1. However, Samples (#3) to (#5) are composite materials of Examples 1 to 3 using a biofiller that has undergone chemical and physical surface modification, and exhibit a speckled pattern design appearance achieved through increased particle size. That is, the latex-coated biofiller of the present invention has different adjusted particle sizes, which can provide customers with preferred design effects when used as a resin reinforcing material.

Claims

1. A resin-reinforced material, comprising: Plant-derived biofiller and a latex coating formed on the surface of the biofiller, The latex coating comprises a carboxyl-containing conjugated diene rubber.

2. The resin-reinforced material according to claim 1, wherein, The biofiller includes one or more of the following: wood powder from pine, spruce, acacia or rubber trees; plants such as kenaf, flax, hemp, jute or bamboo seeds; grains such as wheat or barley; shells such as coconut shells or coffee grounds; and natural fibers such as cellulose or lignocellulose.

3. The resin-reinforced material according to claim 1, wherein, The latex coating includes carboxyl-containing conjugated diene rubber, which is selected from one or more of carboxyl-containing nitrile rubber, carboxyl-containing styrene-butadiene rubber, and carboxyl-containing conjugated diene rubber.

4. The resin-reinforced material according to claim 1, wherein, The biological packing material comprises primary particles and secondary particles formed by the aggregation of one or more primary particles, and The latex coating is formed on the surface of the primary particles and the surface of the secondary particles.

5. The resin-reinforced material according to claim 4, wherein, The average particle size of the primary particles in the biological packing material is 10 μm to 250 μm, and The average particle size of the secondary particles in the biological packing material is between 100 μm and 2500 μm.

6. The resin-reinforced material according to claim 1, wherein, The latex coating is formed on the surface of the biofiller with a thickness of 0.2 μm to 50 μm.

7. The resin-reinforced material according to claim 1, wherein, The resin-reinforcing material, including the biofiller and the latex coating formed on the surface of the biofiller, has an average particle size of 0.1 mm to 10 mm.

8. A method for manufacturing a resin-reinforced material, the method comprising: (S1) Add biological filler to the high-speed mixer and stir, while spraying latex coating liquid to form a latex coating on the surface of the biological filler. and (S2) The biofiller on which the latex coating is formed is dried and then compressed.

9. The method for manufacturing the resin-reinforced material according to claim 8, wherein, The latex coating liquid contains a carboxyl-containing conjugated diene rubber, and the amount of the carboxyl-containing conjugated diene rubber used is from 0.5% by weight to 30% by weight based on the weight of the biofiller.

10. The method for manufacturing the resin-reinforced material according to claim 8, wherein, The stirring is performed at 500 rpm to 1500 rpm.

11. The method for manufacturing the resin-reinforced material according to claim 8, wherein, The compression is carried out at a temperature of 70°C to 250°C and a pressure of 10 bar to 70 bar.

12. A resin composition comprising a resin reinforcing material comprising a polymer resin and a biofiller, wherein a latex coating is formed on the biofiller.

13. The resin composition according to claim 12, wherein, The content of the resin reinforcing material is from 1% to 40% by weight, based on the total weight of the composition.

14. The resin composition according to claim 12, wherein, The polymer resin includes one or more selected from the following: thermoplastic resins, including polylactic acid (PLA), polybutylene adipate (PBAT), polyethylene (PE), polypropylene (PP), acrylonitrile-butadiene-styrene (ABS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), or mixtures thereof; thermosetting resins, including epoxy resins, amino resins, phenolic resins, polyester resins, polyurethane resins, or mixtures thereof.

15. A composite material prepared by extruding the resin composition of claim 12.

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