Surface Treatment Nanocellulose Masterbatch

Abstract

To provide a surface-treated nano cellulose master batch, capable of obtaining a rubber composition excellent in elongation, hardness, water resistance and tear resistance, with nano cellulose homogeneously dispersed.SOLUTION: A surface-treated nano cellulose master batch includes: a rubber constituent; nano cellulose; a resol type and / or novolak type resorcin-formaldehyde initial condensate; and formaldehyde. The surface-treated nano cellulose master batch includes 0.3-15 pts.mass of the nano cellulose based on 100 pts.mass of the rubber constituent, 0.03-1.2 pts.mass of the resol type and / or novolak type resorcin-formaldehyde initial condensate and 0.02-0.8 pts.mass of the formaldehyde based on 1 pt.mass of the nano cellulose.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a surface-treated nanocellulose masterbatch. [Background technology]

[0002] Rubber compositions for tires and the like are required to have excellent properties such as elastic modulus (elongation) and hardness (hardness). To improve these properties, a technique of compounding fillers such as carbon black and silica into the rubber composition is known.

[0003] Furthermore, a technology is also known in which a rubber composition having excellent processability and a good balance of rigidity, breaking characteristics, and fuel economy is provided by dispersing and incorporating chemically modified microfibril cellulose having cationic groups into the rubber composition (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6353169 Summary of the Invention [Problem to be solved by the invention]

[0005] However, nanocellulose such as chemically modified microfibril cellulose has the property of easily agglomerating and converging during processes such as removing moisture, so it can be difficult to maintain a defibrated state down to the nano level when producing a masterbatch containing nanocellulose, and such a masterbatch may not produce a rubber composition with the desired properties. Therefore, there is room for further improvement in terms of obtaining a surface-treated nanocellulose masterbatch in which nanocellulose is uniformly dispersed.

[0006] Therefore, an object of the present invention is to provide a surface-treated nanocellulose masterbatch that can produce a rubber composition in which nanocellulose is uniformly dispersed and which has excellent elongation, hardness, water resistance, and tear resistance. [Means for solving the problem]

[0007] In order to solve the above problems, the present inventors conducted extensive research and found that a surface-treated nanocellulose masterbatch containing a rubber component, nanocellulose, a resol-type and / or novolac-type resorcinol-formaldehyde precondensate, and formaldehyde, in which the nanocellulose is contained in an amount of 0.3 to 15 parts by mass per 100 parts by mass of the rubber component, and the nanocellulose is contained in an amount of 0.03 to 1.2 parts by mass of the resol-type and / or novolac-type resorcinol-formaldehyde precondensate and 0.02 to 0.8 parts by mass of formaldehyde per 1 part by mass of the nanocellulose, allows the nanocellulose to be uniformly dispersed, and furthermore, a rubber composition can be obtained which maintains elongation and hardness, has excellent water resistance, and has improved tear resistance, thereby completing the present invention.

[0008] That is, the present invention provides the following: <1> ~ <5> is. <1> A surface-treated nanocellulose masterbatch containing a rubber component, nanocellulose, a resol-type and / or novolac-type resorcinol-formaldehyde precondensate, and formaldehyde, wherein the surface-treated nanocellulose masterbatch contains 0.3 to 15 parts by mass of the nanocellulose per 100 parts by mass of the rubber component, 0.03 to 1.2 parts by mass of the resol-type and / or novolac-type resorcinol-formaldehyde precondensate, and 0.02 to 0.8 parts by mass of the formaldehyde per 1 part by mass of the nanocellulose. <2> The rubber component includes a diene rubber and a styrene-butadiene-vinylpyridine terpolymer. <1> The surface-treated nanocellulose masterbatch according to claim 1. <3> Further, containing carbon black and / or silica, <1> or <2> The surface-treated nanocellulose masterbatch according to claim 1. <4> Further, the rubber composition contains 0.1 to 15 parts by mass of an unsaturated fatty acid metal salt relative to 100 parts by mass of the rubber component. <1> ~ <3> 1. The surface-treated nanocellulose masterbatch according to any one of the preceding items. <5> The unsaturated fatty acid metal salt is a metal acrylate and / or a metal methacrylate. <4> The surface-treated nanocellulose masterbatch according to claim 1. [Effects of the Invention]

[0009] According to the present invention, it is possible to obtain a surface-treated nanocellulose masterbatch that can produce a rubber composition in which nanocellulose is uniformly dispersed, elongation and hardness are maintained, water resistance is excellent, and tear resistance is also improved. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will now be described. The present invention provides a surface-treated nanocellulose masterbatch containing a rubber component, nanocellulose, a resol-type and / or novolac-type resorcinol-formaldehyde precondensate, and formaldehyde. The surface-treated nanocellulose masterbatch contains 0.3 to 15 parts by mass of nanocellulose per 100 parts by mass of the rubber component, 0.03 to 1.2 parts by mass of the resol-type and / or novolac-type resorcinol-formaldehyde precondensate, and 0.02 to 0.8 parts by mass of formaldehyde per 1 part by mass of nanocellulose. Hereinafter, this surface-treated nanocellulose masterbatch will also be referred to as the "surface-treated nanocellulose masterbatch of the present invention."

[0011] First, the rubber component to be compounded into the surface-treated nanocellulose masterbatch of the present invention can be a typical rubber component used in the rubber industry, such as a diene rubber or butyl rubber. For the surface-treated nanocellulose masterbatch of the present invention, it is preferable to use rubber latex, which is an aqueous dispersion in which the rubber component is colloidally dispersed in water, as the raw material. Furthermore, from the viewpoint of further enhancing the dispersibility of nanocellulose and other components, as described below, this rubber component is preferably a rubber component containing a diene rubber and a styrene-butadiene-vinylpyridine terpolymer (VP).

[0012] The diene rubber is a rubber component having a double bond in the polymer main chain, and examples thereof include natural rubber (NR), butadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene copolymer rubber (NBR), chloroprene rubber (CR), isoprene rubber (IR), etc. The weight-average molecular weight of the diene rubber is preferably 50,000 to 3,000,000, and more preferably 100,000 to 2,000,000. Here, in the present invention, the "weight average molecular weight" means a value measured in terms of standard polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent.

[0013] The surface-treated nanocellulose masterbatch of the present invention is a masterbatch containing nanocellulose that has been mechanically or chemically surface-treated (mechanically defibrated, chemically modified, etc.). Here, in the present invention, "nanocellulose" refers to ultrafine fibers composed of cellulose microfibrils with an average fiber diameter of 1 to 1000 nm, and includes cellulose nanofibers (CNF) with an average fiber length of 0.5 to 5 μm and cellulose nanocrystals (CNC) with an average fiber length of 0.1 to 0.5 μm. In the present invention, surface-treated nanocellulose may also be referred to simply as "nanocellulose."

[0014] The cellulose used as the raw material for nanocellulose can be derived from either wood or non-wood sources (bacteria, algae, cotton, etc.), and is not particularly limited. Examples of methods for producing nanocellulose include adding water to the raw cellulose and processing it in a mixer or similar to prepare a slurry in which the cellulose is dispersed in water, and then directly applying mechanical shear force using a high-pressure or ultrasonic device to defibrate the slurry; or chemically treating the slurry with oxidation, alkali, acid hydrolysis, or other methods to modify the cellulose and make it easier to defibrate, and then applying mechanical shear force using a disperser or similar. By performing this chemical treatment before defibration, the cellulose can be defibrated into finer, more uniform fibers with less energy, making it easier to obtain chemically modified nanocellulose. Examples of chemical treatments include treatment with chemical treating agents such as 2,2,6,6-tetramethylpiperidine-1-oxyl (hereinafter referred to as "TEMPO"), 4-acetamido-TEMPO, 4-carboxy-TEMPO, 4-amino-TEMPO, 4-hydroxy-TEMPO, 4-phosphonoxy-TEMPO, phosphate esters, periodic acid, alkali metal hydroxides, and carbon disulfide. Alternatively, chemical treatments may be performed after mechanical defibration of cellulose. In addition to the aforementioned chemical treatments, cellulase treatment, carboxymethylation, esterification, or treatment with a cationic polymer may be performed after the defibration process to further enhance affinity with the rubber component. In the present invention, it is preferable to use nanocellulose having an anion-forming group (e.g., one or more selected from the group consisting of a carboxyl group, a phosphate ester group, a phosphite ester group, a xanthate group, a sulfone group, a sulfate group, and a thiolate group) because this increases the affinity with the resole-type and / or novolac-type resorcinol-formaldehyde precondensates described below.

[0015] The average fiber diameter of this nanocellulose is 1 to 1,000 nm, preferably 1 to 200 nm. The average aspect ratio of the nanocellulose (average fiber length / average fiber diameter) is preferably 10 to 1,000, more preferably 50 to 500. If the average fiber diameter is below the above range and / or the average aspect ratio exceeds the above range, the dispersibility of the nanocellulose may decrease. If the average fiber diameter exceeds the above range and / or the average aspect ratio is below the above range, the reinforcing performance of the nanocellulose may decrease.

[0016] Here, in the present invention, the "average fiber diameter" and "average fiber length" of nanocellulose refer to the average values ​​of fiber diameter and fiber length obtained by preparing an aqueous nanocellulose dispersion with a solid content of 0.05 to 0.1% by mass, obtaining electron microscope images by TEM or SEM observation at an appropriate magnification depending on the size of the constituent fibers, and measuring at least 50 or more fibers in the images. The average aspect ratio is then calculated from the average fiber length and average fiber diameter obtained in this way.

[0017] In the present invention, the surface-treated nanocellulose masterbatch is obtained by adding 0.3 to 15 parts by mass, preferably 0.3 to 12 parts by mass, more preferably 0.4 to 10 parts by mass, even more preferably 0.4 to 8 parts by mass, and even more preferably 0.5 to 5 parts by mass of nanocellulose per 100 parts by mass of the rubber component. If the amount of nanocellulose is less than 0.3 parts by mass per 100 parts by mass of the rubber component, the mechanical properties of the rubber composition obtained from the surface-treated nanocellulose masterbatch may not be sufficiently improved. On the other hand, if the amount of nanocellulose is more than 15 parts by mass per 100 parts by mass of the rubber component, the cost of the resulting surface-treated nanocellulose masterbatch may be high, and further, the nanocellulose may not be uniformly dispersed. In the present invention, nanocellulose may be dispersed in water to form a dispersion (solid content of about 0.1 to 10% by mass) and then mixed with rubber latex, etc. Alternatively, nanocellulose from which water has been removed may be mixed with rubber latex, etc.

[0018] Furthermore, the surface-treated nanocellulose masterbatch of the present invention contains, in addition to nanocellulose, a resol-type and / or novolac-type resorcinol-formaldehyde precondensate and formaldehyde.

[0019] Here, in the present invention, the "resorcinol-formaldehyde precondensate (RF resin)" refers to a condensate (oligomer) obtained by subjecting resorcinol, a phenolic resin, to a condensation reaction with formaldehyde in the presence of a catalyst, and the degree of polymerization is preferably about 5 to 15. Furthermore, this resorcinol-formaldehyde precondensate may contain unreacted resorcinol and / or formaldehyde. A methylol-containing condensate obtained by condensation of resorcinol / formaldehyde in a molar ratio of 1 / 1 to 3 in the presence of an alkaline catalyst such as sodium hydroxide or sodium carbonate is called a resorcinol-formaldehyde precondensate (a condensate represented by chemical formula (1) in the following formula (where n is the degree of polymerization)). A methylol-free condensate obtained by condensation of resorcinol / formaldehyde in a molar ratio of 1 / 0.8 to 0.9 in the presence of an acid catalyst such as oxalic acid is called a novolac-type resorcinol-formaldehyde precondensate (a condensate represented by chemical formula (2) in the following formula (where m is the degree of polymerization). In the surface-treated nanocellulose masterbatch of the present invention, this resorcinol-formaldehyde precondensate may be either a resole type or a novolac type, with the novolac type being preferred.

[0020] [ka]

[0021] [ka]

[0022] In the present invention, the surface-treated nanocellulose masterbatch is obtained by adjusting the content of resol and / or novolac resorcinol-formaldehyde precondensates to 0.03 to 1.2 parts by mass, preferably 0.05 to 0.8 parts by mass, more preferably 0.06 to 0.6 parts by mass, and even more preferably 0.08 to 0.4 parts by mass per part by mass of nanocellulose, and the content of formaldehyde to 0.02 to 0.8 parts by mass, preferably 0.03 to 0.5 parts by mass, more preferably 0.04 to 0.4 parts by mass, and even more preferably 0.05 to 0.3 parts by mass. If the resorcinol-formaldehyde precondensates contain unreacted formaldehyde, this unreacted formaldehyde content is also included in the formaldehyde content of the surface-treated nanocellulose masterbatch of the present invention. If the content of these is less than the above range, the nanocellulose may not be uniformly dispersed, and the mechanical properties of the rubber composition obtained from this surface-treated nanocellulose masterbatch may not be sufficiently improved. On the other hand, if the content of these is more than the above range, the tear resistance and elongation of the rubber composition obtained from this surface-treated nanocellulose masterbatch may actually decrease.

[0023] The surface-treated nanocellulose masterbatch of the present invention may further contain a filler. Examples of such fillers include carbon black, silica, clay, aluminum hydroxide, calcium carbonate, mica, talc, aluminum hydroxide, aluminum oxide, titanium oxide, barium sulfate, and lecithin. These fillers can be used singly or in combination. In particular, the incorporation of carbon black and / or silica (fumed silica, calcined silica, precipitated silica, pulverized silica, fused silica, colloidal silica, etc.) is highly preferred from the perspective of improving the strength and hardness of the rubber composition obtained from the surface-treated nanocellulose masterbatch of the present invention and dispersing the nanocellulose more uniformly. The content of the filler in the surface-treated nanocellulose masterbatch of the present invention is preferably 10 parts by mass or more, more preferably 20 to 100 parts by mass, even more preferably 30 to 80 parts by mass, and even more preferably 40 to 70 parts by mass, per 100 parts by mass of the rubber component.

[0024] In the present invention, "carbon black" refers to fine carbon particles with a diameter of approximately 3 to 500 nm that are manufactured under industrial quality control, and "silica" refers to silicon dioxide (SiO2) or a substance composed of silicon dioxide.

[0025] Here, an example of a method for producing the surface-treated nanocellulose masterbatch of the present invention is described. First, nanocellulose is dispersed in rubber latex at 0.3 to 15 parts by mass per 100 parts by mass of the rubber component (solid content of the rubber latex), and 0.03 to 1.2 parts by mass of a resol-type and / or novolac-type resorcinol-formaldehyde precondensate and 0.02 to 0.8 parts by mass of formaldehyde are added per part by mass of the nanocellulose. If necessary, fillers and other additives are further added to obtain a raw material dispersion in a slurry state with a solid content of 60% by mass or less. The dispersion method is not particularly limited, and mechanical methods can be used. Furthermore, nanocellulose is preferably dispersed in water before being mixed with the rubber latex. The concentration of this aqueous dispersion is preferably 0.1 to 10% by mass, more preferably 0.1 to 5% by mass. By maintaining the concentration of the nanocellulose aqueous dispersion within this range, the defibrated nanocellulose can be more uniformly dispersed in the aqueous dispersion. It is also preferable to mix formaldehyde in the form of an aqueous solution (formalin) with rubber latex.

[0026] The solid content of the raw material dispersion is preferably 60% by mass or less, more preferably 2 to 50% by mass, and even more preferably 5 to 50% by mass. If the solid content exceeds 60% by mass, the viscosity of the raw material dispersion may increase and the stability may decrease.

[0027] Then, a coagulant is added to this raw material dispersion to aggregate and coagulate the polymer components, water is removed by filtration, the coagulated material is washed to remove the coagulant as needed, and the surface-treated nanocellulose masterbatch of the present invention is obtained by drying, etc. Here, as the coagulant, inorganic salts (sodium chloride, potassium chloride, etc.) and metal salts of unsaturated fatty acids (metal salts of acrylic acid, metal salts of methacrylic acid, etc.) can be used.

[0028] In particular, using an unsaturated fatty acid metal salt as a coagulant is preferable because, even if the unsaturated fatty acid metal salt is contained in the resulting surface-treated nanocellulose masterbatch, the properties of the rubber composition obtained from this surface-treated nanocellulose masterbatch, such as hardness and elongation, are not reduced, and the process of washing the coagulated product after the aggregation and coagulation of the raw material dispersion can be omitted. As the unsaturated fatty acid metal salt, it is highly preferable to use a metal acrylate and / or a metal methacrylate. Preferred metal salts include sodium, potassium, calcium, magnesium, aluminum, zinc, and neodymium. When an unsaturated fatty acid metal salt is used as a coagulant, it is preferable to use the unsaturated fatty acid metal salt in an amount of preferably 0.1 to 15 parts by mass, more preferably 0.2 to 10 parts by mass, even more preferably 0.2 to 5 parts by mass, even more preferably 0.2 to 2 parts by mass, and still more preferably 0.3 to 2 parts by mass per 100 parts by mass of the rubber component, since this will not affect the properties of the rubber composition obtained while fully exerting the coagulation and coagulation effects of the polymer component.

[0029] Then, using the surface-treated nanocellulose masterbatch of the present invention, various additives commonly used in rubber compositions, such as fillers, silane coupling agents, zinc oxide (zinc white), stearic acid, adhesive resins, pressure-sensitive adhesives, mastication accelerators, antioxidants, waxes, processing aids, aromatic oils, liquid polymers, terpene resins, thermosetting resins, vulcanizing agents (e.g., sulfur), vulcanization accelerators, and crosslinking agents, are blended in appropriate amounts, and mixed and kneaded by known methods to form a rubber composition. Additives other than vulcanizing agents, vulcanization accelerators, and crosslinking agents may be added to the raw material dispersion when obtaining the surface-treated nanocellulose masterbatch of the present invention.

[0030] The rubber composition obtained using such a surface-treated nanocellulose masterbatch of the present invention has nanocellulose dispersed uniformly, maintains elongation and hardness, has excellent water resistance, and has improved tear resistance.

[0031] Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples, and various modifications are possible within the technical concept of the present invention. [Example]

[0032] (Test Example 1) A masterbatch was prepared using the raw materials shown in Table 1 below. Specifically, a rubber latex (solid content (dry rubber content) 40.5% by mass, SBR:VP ratio 95:5) consisting of styrene-butadiene copolymer rubber latex (SBR; manufactured by Nippon Zeon Co., Ltd., Nipol LX112) and styrene-butadiene-vinylpyridine terpolymer latex (VP; manufactured by Nippon Zeon Co., Ltd., Nipol LX2518FS) was mixed and dispersed in an aqueous dispersion (solid content 1.0% by mass) of oxidized nanocellulose (manufactured by Nippon Paper Industries Co., Ltd., Cellenpia), a novolac-type resorcinol-formaldehyde precondensate (RF resin (Sumikanol® 700S), manufactured by Sumitomo Chemical Co., Ltd.), and an aqueous formaldehyde solution (37% solution, manufactured by Kanto Chemical Co., Ltd.) in the mass ratios shown in Table 1 below to obtain raw material dispersions in a slurry state with a solid content concentration of 60% by mass or less (Examples 1 and 2 and Comparative Examples 2 and 3). In Comparative Example 1, the rubber latex and the nanocellulose were mixed and dispersed with dodecyltrimethylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) as a surfactant in the mass ratio shown in Table 1 below as solid contents to obtain a raw material dispersion in a slurry state in the same manner. In Comparative Example 4, the rubber latex and carbon black (Seast (registered trademark), manufactured by KH Tokai Carbon Co., Ltd.) were mixed and dispersed with the mass ratio shown in Table 1 below as solid contents to obtain a raw material dispersion in a slurry state in the same manner.

[0033] [Table 1]

[0034] The raw material dispersions of Examples 1 and 2 and Comparative Examples 1 to 4 were coagulated by salting out using sodium chloride as a coagulant. The coagulated material was then recovered, washed, and dried to obtain masterbatches. The washing procedure involved filtering the coagulated material under reduced pressure using a Buchner funnel while spraying distilled water onto the surface to wash away the sodium chloride. This was repeated five times. The washed coagulated material was then spread on a tray and placed in a constant temperature oven at 70°C for 24 hours for drying. Zinc oxide (ZnO, manufactured by Seido Chemical Industry Co., Ltd.), stearic acid (manufactured by NOF Corporation), a vulcanization accelerator (Noccela NS-P, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), and sulfur (Mucron OT-20, manufactured by Shikoku Chemical Industry Co., Ltd.) were added to each of the resulting masterbatches, and the mixture was mixed using an open roll mill. The mixture was then press-vulcanized in a 15 cm x 15 cm x 0.2 cm mold at 160°C for 15 minutes to prepare vulcanized rubber test pieces. The vulcanized rubber specimens were then subjected to a tensile test at a rate of 500 mm / min in accordance with JIS K6251:2010 to measure the tensile stress at 100% elongation (M100: MPa) and the elongation at break (= elongation at break: Eb) at room temperature (20°C). A tear test at a rate of 500 mm / min in accordance with JIS K6252:2015 was also performed to measure the tear stress at break (MPa) at room temperature (20°C). Furthermore, an immersion test using water as the test liquid was performed in accordance with JIS K6258:2016 to evaluate water resistance.

[0035] These results are shown in the following Table 2. Note that M100, Eb and tear stress are shown as relative values ​​(index (index%)) with Comparative Example 1 being set at 100. These results show that the surface-treated nanocellulose masterbatch of the present invention, which contains a specified amount of oxidized nanocellulose, novolac-type resorcinol-formaldehyde initial condensate, and formaldehyde, can produce a rubber composition that combines elongation and hardness, and also has good tear resistance (tear strength) and water resistance.

[0036] [Table 2]

[0037] (Test Example 2) A masterbatch was prepared using the raw materials shown in Table 3 below. Specifically, a rubber latex (solids content (dry rubber content) 40.5% by mass, SBR:VP ratio 95:5) consisting of styrene-butadiene copolymer rubber latex (SBR; manufactured by Nippon Zeon Co., Ltd., Nipol LX112) and styrene-butadiene-vinylpyridine terpolymer latex (VP; manufactured by Nippon Zeon Co., Ltd., Nipol LX2518FS) was mixed and dispersed in an aqueous dispersion (solids content 1.0% by mass) of oxidized nanocellulose (manufactured by Nippon Paper Industries Co., Ltd., Cellenpia), a novolac-type resorcinol-formaldehyde precondensate (RF resin (Sumikanol® 700S), manufactured by Sumitomo Chemical Co., Ltd.), and an aqueous formaldehyde solution (37% solution, manufactured by Kanto Chemical Co., Ltd.) in the mass ratios shown in the upper row of Table 3 below, to obtain a raw material dispersion in a slurry state with a solids concentration of 60% by mass or less. This raw material dispersion was then coagulated using the amount of coagulant shown in the lower part of Table 3 below (sodium chloride was manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., and both acrylates were manufactured by Asada Chemical Industry Co., Ltd.) per 100 parts by mass of the solid content of the rubber latex, and the coagulated material was recovered and dried to obtain masterbatches (Examples 3 to 5 and Comparative Examples 5 and 7). The drying was carried out by spreading the obtained coagulated material on a tray and placing it in a thermostatic oven at 70°C for 24 hours. Note that Comparative Example 5 was washed before drying. This washing was carried out by spraying distilled water on the surface of the coagulated material while filtering it under reduced pressure using a Buchner funnel to wash away the sodium chloride, and this operation was repeated five times. Note that Comparative Example 6 did not coagulate, and a masterbatch could not be obtained.

[0038] [Table 3]

[0039] For each of the obtained masterbatches, vulcanized rubber test pieces were prepared in the same manner as in Test Example 1. Using the obtained vulcanized rubber test pieces, a tensile test was carried out at a tensile speed of 500 mm / min in accordance with JIS K6251:2010, and the tensile stress at 100% elongation (M100: MPa) and elongation at break (= elongation at break: Eb) were measured at room temperature (20°C).

[0040] These results, as well as the coagulation properties of each masterbatch and the necessity of washing after coagulation, are shown in Table 4. Note that M100 and Eb are shown as relative values ​​(index (index%)) with Comparative Example 5 set to 100. These results show that the surface-treated nanocellulose masterbatch of the present invention, which contains a specified amount of oxidized nanocellulose, novolac-type resorcinol-formaldehyde initial condensate, and formaldehyde and is coagulated with a specified amount of unsaturated fatty acid metal salt (sodium acrylate or calcium acrylate), has excellent coagulation properties, does not require washing after coagulation, and can produce a rubber composition that combines elongation and hardness.

[0041] [Table 4]

Claims

1. A surface-treated nanocellulose masterbatch containing a rubber component, nanocellulose having an anion-forming group, a novolak-type resorcinol-formaldehyde initial condensate, and formaldehyde, the rubber component includes a diene rubber and a styrene-butadiene-vinylpyridine terpolymer; The nanocellulose is contained in an amount of 0.3 to 8 parts by mass relative to 100 parts by mass of the rubber component, A surface-treated nanocellulose masterbatch containing 0.03 to 0.4 parts by mass of the novolak-type resorcinol-formaldehyde initial condensate and 0.02 to 0.4 parts by mass of the formaldehyde relative to 1 part by mass of the nanocellulose.

2. The surface-treated nanocellulose masterbatch according to claim 1, further comprising carbon black and / or silica.

Images