A lignin-based thermoplastic resin for rubber reinforcement and its synthesis method and application

Abstract

The present application relates to the technical fields of bio-based polymer materials and rubber auxiliary, and particularly relates to a lignin-based thermoplastic resin for rubber reinforcement, a synthesis method and application thereof. In the method, lignin, a phenolic reagent and an acidic catalyst are liquefied in a slurry bed reactor, after removing the unliquefied residues in a hot state, phenol and a viscosity regulator are added for pre-reaction, then an aldehyde solution is added for condensation and vacuum drying, and finally the lignin-based thermoplastic resin is obtained. The obtained resin has adjustable glass transition temperature, softening point and melting viscosity, and is suitable for tire rubber reinforcement.

Description

Technical Field

[0001] This invention relates to the field of bio-based polymer materials and rubber additives, and in particular to a lignin-based thermoplastic resin for rubber reinforcement, its synthesis method, and its application. Background Technology

[0002] Phenolic resins are commonly used reinforcing, hardening, and adhesion-promoting resins in the tire and rubber industry. They can improve the hardness, modulus, abrasion resistance, tear strength, and adhesion properties of rubber compounds, particularly in the cord and bead areas, during rubber compounding and vulcanization. Traditional phenolic resins are typically prepared using phenol and formaldehyde as the main raw materials, relying heavily on the petrochemical system. This process presents challenges such as non-renewable resources, fluctuating raw material prices, and a high environmental impact during production. With the development of green tires, bio-based materials, and low-carbon manufacturing technologies, utilizing renewable biomass aromatic resources to partially replace petroleum-based phenols in the preparation of rubber reinforcing resins has become an important direction for phenolic resin modification and rubber additive development.

[0003] Lignin is a natural aromatic polymer found in plant cell walls, widely derived from pulping and papermaking, biorefining, and agricultural and forestry waste processing. Its structure contains functional groups such as phenylpropane units, phenolic hydroxyl groups, alcoholic hydroxyl groups, and methoxy groups, theoretically making it a potential aromatic component or phenol substitute in phenolic resin synthesis. Compared to polysaccharide biomass such as starch and cellulose, lignin possesses a natural aromatic ring structure, more closely resembling the basic structural unit of phenolic resins, thus exhibiting high potential for high-value utilization. However, industrial lignin typically suffers from problems such as wide molecular weight distribution, heterogeneous structure, high degree of condensation, low reactivity, poor melt flowability, and insufficient compatibility with rubber matrices. Directly adding lignin to rubber systems often results in uneven dispersion, weak interfacial bonding, increased processing viscosity, or unstable reinforcing effects, failing to meet the comprehensive requirements of tire rubber for processing safety, dynamic performance, and uniform reinforcement.

[0004] Several improvements have been proposed in the existing technology for the application of lignin in rubber reinforcing resins. For example, patent application CN103509164A discloses a lignin-based reinforcing resin and its preparation method. This method uses phenol, lignin, an acidic catalyst, turpentine, and formaldehyde as raw materials to prepare the lignin-based reinforcing resin through a phenolic condensation reaction, and then uses it for rubber reinforcement. This scheme utilizes the combination of lignin and phenolic resin, and improves the compatibility between the resin and rubber through turpentine, thus improving the hardness, tear resistance, and processing performance of rubber products to a certain extent. However, this type of scheme mainly focuses on introducing lignin and turpentine modification into the traditional phenolic resin system, and does not fully solve the problem of synergistic control between the degree of lignin liquefaction, unliquefied residue, resin thermoplastic window, and melt flowability at the mixing temperature. When the degree of lignin condensation is high or the residue content is high, it may still lead to a decrease in resin dispersibility, poor rubber flowability, and uneven reinforcement.

[0005] For example, patent application CN103554400A discloses a lignin liquefaction method for preparing thermoplastic phenolic resin. This method uses phenol, a heteropolyacid catalyst, and enzymatically hydrolyzed lignin to liquefy at 90℃-160℃ for 1-3 hours, yielding a liquefied product suitable for preparing lignin-based thermoplastic phenolic resin. The key point of this approach is to improve the utilization efficiency of lignin as a phenol substitute by catalyzing the liquefaction of lignin with heteropolyacids, thus providing a relatively active phenolic liquefaction product for the preparation of lignin-based phenolic resin. However, this approach primarily addresses the issues of lignin liquefaction and phenol substitution, with insufficient attention paid to the processing compatibility of the liquefied product when further used in rubber reinforcing resins. In particular, it fails to systematically control the glass transition temperature, softening point, melt viscosity, and resin dispersibility required for tire rubber compounding, and it does not explicitly utilize viscosity modifiers in the pre-reaction process to reduce the processing viscosity of the subsequent condensation resin and improve its thermoplasticity.

[0006] Therefore, although existing lignin-based phenolic resin technologies can improve lignin utilization to some extent or enable the application of lignin in rubber reinforcing materials, they still have the following shortcomings: First, unliquefied residues in lignin liquefaction products can easily affect resin uniformity and rubber mixing and dispersibility; Second, when directly performing phenolic condensation, the resin is prone to forming structures with high molecular weight or strong cross-linking tendency, resulting in high softening point and melt viscosity; Third, existing solutions lack thermoplastic control for the processing temperature window of rubber tires, and the resin may experience problems such as insufficient melting, difficulty in dispersion, localized heat generation, or decreased processing safety during the mixing process; Fourth, traditional phenolic resins are highly dependent on petroleum-based phenols and formaldehyde, and there is still room for improvement in bio-based content and low carbonization level.

[0007] Based on the above problems, it is necessary to develop a new method for synthesizing lignin-based thermoplastic resins. This method involves first fully liquefying lignin in a phenolic reagent and removing any unliquefied residue. Then, the phenolic oil reaction solution is pre-regulated using a viscosity modifier, followed by a condensation reaction with an aldehyde solution. This yields a lignin-based thermoplastic phenolic resin with adjustable glass transition temperature, softening point, and melt viscosity. This resin is better suited for tire rubber compounding and vulcanization processes, improving lignin utilization while enhancing its dispersibility, processing fluidity, and reinforcing uniformity within the rubber matrix. Summary of the Invention

[0008] The technical objective of this invention is to address the problems of insufficient lignin reactivity, liquefaction residue affecting resin uniformity, high resin softening point and melt viscosity, difficulty in rubber mixing and dispersion, and unstable reinforcement effect of existing lignin-based phenolic resins. This invention provides a method for synthesizing and applying a lignin-based thermoplastic resin for rubber reinforcement. Through the synergistic control of lignin phenol liquefaction, residue removal, viscosity modifier pre-regulation, and aldehyde condensation reaction, lignin is efficiently converted into a thermoplastic phenolic resin suitable for rubber processing and tire reinforcement.

[0009] Firstly, in order to achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0010] A method for synthesizing a lignin-based thermoplastic resin for rubber reinforcement includes the following steps:

[0011] S1, plant-derived lignin, phenolic reagents and acidic catalysts are added to a slurry bed reactor to form a slurry reaction system with a mass concentration of 10wt%-50wt% in the phenolic reagents, and the reaction is carried out at 100℃-250℃ for 1 hour-8 hours to cause phenolization and liquefaction of lignin, and liquefied reactants containing phenolic oil are obtained.

[0012] S2, perform hot solid-liquid separation on the liquefied reactants to remove unliquefied residue and obtain phenolic oil solution;

[0013] S3, without adding aldehyde solution, add phenol and 0.1wt%-10wt% viscosity modifier to the phenolic oil solution, and pre-react at 100℃-150℃ for 1 hour-3 hours, so that the viscosity modifier is pre-mixed or pre-reacted with the liquefied lignin component in the phenolic oil to obtain the viscosity-adjusted phenolic oil reaction solution.

[0014] S4, the viscosity-adjusted phenolic oil reaction solution is cooled to 80℃-105℃, an aldehyde solution is added to carry out a condensation reaction for 1 hour to 5 hours, and then vacuum dried to obtain a lignin-based thermoplastic resin for rubber reinforcement.

[0015] In the condensation reaction, the molar ratio of phenolic components to aldehyde components is 1:0.5-1:1, and the resulting lignin-based thermoplastic resin has a glass transition temperature of 30℃-80℃, a softening point of 50℃-110℃, and a melt viscosity of 10. 4 mPa·s⁻¹⁰ 8 mPa·s.

[0016] Preferably, the phenolic reagent is one or more of phenol, alkylphenol, and natural polyphenols; the alkylphenol is selected from one or more of p-tert-butylphenol, octylphenol, nonylphenol, and dodecylphenol; and the natural polyphenol is selected from one or more of plant tannins, wood tar creosote, and cashew phenol.

[0017] And / or, the acidic catalyst is one or more of hydrochloric acid, sulfuric acid, oxalic acid, boric acid, phosphoric acid, phosphotungstic acid, and silicotungstic acid, and the amount of the acidic catalyst is 1wt%-10wt% of the total mass of the liquefaction reaction system.

[0018] Preferably, the slurry reaction system described in S1 is reacted under stirring, with a stirring rate of 100 r / min to 600 r / min; the liquefaction reaction temperature is 120℃ to 160℃, and the liquefaction reaction time is 1.5 hours to 4 hours.

[0019] And / or, the hot solid-liquid separation described in S2 is carried out at 80℃-140℃ to separate the unliquefied residue from the phenolic oil solution, thereby reducing the impact of unliquefied lignin particles on the subsequent condensation reaction and the dispersibility of rubber compounding.

[0020] And / or, the molar ratio of phenolic oil to phenol in S3 is 1:10-10:1, and the phenol is used to adjust the content of condensable phenolic hydroxyl groups in the phenolic oil reaction solution and the rate of subsequent condensation reaction.

[0021] Preferably, the viscosity modifier is a polyether compound or a polyester compound; the polyether compound is selected from at least one of polyethylene glycol, polypropylene glycol, ethylene oxide-propylene oxide copolymer, and polytetrahydrofuran; the polyester compound is selected from at least one of polyester polyol and polycaprolactone diol.

[0022] And / or, the aldehyde solution is formaldehyde, aliphatic dialdehyde, aromatic aldehyde, or bio-based aldehyde; the aliphatic dialdehyde is selected from one or more of glyoxal, glutaraldehyde, and succinaldehyde; the aromatic aldehyde is selected from one or more of benzaldehyde and p-hydroxybenzaldehyde; the bio-based aldehyde is selected from one or more of furfural and 5-hydroxymethylfurfural.

[0023] Preferably, the vacuum drying temperature in S4 is 70℃-90℃, the time is 8 hours-16 hours, and the vacuum degree is -0.08MPa to -0.10MPa.

[0024] Secondly, the present invention also provides a lignin-based thermoplastic resin for rubber reinforcement, which is prepared by the aforementioned synthesis method.

[0025] Preferably, the lignin-based thermoplastic resin can soften and disperse in the rubber matrix at the rubber mixing temperature, and participate in the formation of the rubber reinforcing network during vulcanization, thereby improving the hardness, modulus, tear strength or abrasion resistance of the rubber.

[0026] Thirdly, the present invention also provides the application of a lignin-based thermoplastic resin in the preparation of tire rubber reinforcing materials, wherein the lignin-based thermoplastic resin is the lignin-based thermoplastic resin described above.

[0027] Preferably, the tire rubber reinforcing material is used in the tread rubber, sidewall rubber, tread bead rubber, bead reinforcing rubber, or cord adhesive.

[0028] Fourthly, the present invention also provides a rubber composition comprising 100 parts by weight of a rubber matrix and 1-20 parts by weight of the lignin-based thermoplastic resin described above; wherein the rubber matrix is ​​one or more selected from natural rubber, styrene-butadiene rubber, cis-butadiene rubber, isoprene rubber, nitrile rubber, and brominated butyl rubber.

[0029] The technical advantages of this invention are as follows: This invention uses plant-derived lignin as the main bio-based aromatic raw material. First, lignin is liquefied in a slurry-bed reactor using phenolic reagents and an acidic catalyst, transforming the high-molecular-weight condensation structures in lignin that are difficult to directly participate in condensation reactions into highly reactive phenolic oil components. Unliquefied residue is removed through hot solid-liquid separation, improving the uniformity of the subsequent resin condensation system and the dispersibility of the rubber compound from the source. Before adding the aldehyde solution, a polyether or polyester viscosity modifier is introduced to allow it to fully react with the phenolic oil solution. Mixing or pre-reaction can reduce the molecular weight growth rate and excessive cross-linking tendency of subsequent condensation products, thereby maintaining the thermoplastic characteristics of the resulting resin and enabling adjustable control of glass transition temperature, softening point, and melt viscosity. By controlling the molar ratio of phenolic components to aldehyde components, as well as the condensation reaction temperature and time, the resulting lignin-based thermoplastic resin can soften and disperse well in the rubber matrix at the rubber mixing temperature, avoiding problems such as mixing difficulties, localized heat generation, poor rubber flowability, and uneven reinforcement caused by traditional direct addition of lignin or high-softening-point phenolic resins. Compared with traditional petroleum-based phenolic reinforcing resins, this invention increases the utilization ratio of renewable lignin and reduces dependence on petroleum-based phenols. Compared with existing direct lignin condensation or simple liquefaction modification technologies, the resin obtained by this invention is more suitable for rubber systems such as tire tread rubber, sidewall rubber, gusset rubber, bead reinforcement rubber, and cord adhesives. It can improve the hardness, modulus, tear strength, abrasion resistance, and reinforcement uniformity of rubber products while improving processing flowability, and has green, low-carbon, and industrial application value. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the synthesis process of the lignin-based thermoplastic resin used for rubber reinforcement according to the present invention.

[0031] Figure 2 This is a comparison chart of the glass transition temperature, softening point, and melt viscosity of the resins obtained in different embodiments and comparative examples.

[0032] Figure 3 The graph shows the torque variation curves of rubber compounding after adding different resins.

[0033] Figure 4 This is a comparison chart showing the hardness, tensile stress, tensile strength, and tear strength of vulcanizates after adding different resins.

[0034] Figure 5 A comparison chart of the dynamic mechanical properties of vulcanizates with the addition of different resins. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Without departing from the concept of the present invention, those skilled in the art can make appropriate adjustments to the process parameters based on the source of lignin, the type of phenolic reagent, the type of aldehyde solution, the molecular weight of the viscosity modifier, and the application location in the rubber; all such adjustments should fall within the scope of protection of the present invention.

[0036] This invention provides a method for synthesizing a lignin-based thermoplastic resin for rubber reinforcement. The core of this method involves: first, phenolic liquefaction of lignin in a slurry-bed reactor under the action of phenolic reagents and an acidic catalyst, transforming the low-reactivity, high-molecular-weight, and difficult-to-melt-disperse condensation structure of industrial lignin into a highly reactive phenolic oil component; then, hot solid-liquid separation is performed while the liquefied reactants still possess good fluidity to remove unliquefied residues; next, a polyether or polyester viscosity modifier is added without the addition of an aldehyde solution, allowing the viscosity modifier to be fully premixed or pre-reacted with the phenolic oil solution; finally, a condensation reaction is carried out under a low aldehyde ratio, followed by vacuum drying to obtain the lignin-based thermoplastic resin. By controlling the above process sequence, the obtained resin simultaneously exhibits high bio-based lignin utilization, good thermoplasticity, a suitable softening point and melt viscosity for rubber compounding, and a relatively stable rubber reinforcement effect.

[0037] like Figure 1 As shown, the process of this invention sequentially includes a lignin liquefaction step, a residue removal step, a viscosity modifier pre-reaction step, an aldehyde condensation step, and a vacuum drying step. The lignin liquefaction step is used to improve the reactivity of lignin; the residue removal step is used to improve the uniformity of the resin system; the viscosity modifier pre-reaction step is used to suppress excessively rapid thickening and over-condensation during subsequent condensation; the aldehyde condensation step is used to form a resin with a thermoplastic phenolic structure; and the vacuum drying step is used to remove moisture, free phenols, and small molecule volatiles, bringing the resin to the stable state required for subsequent rubber compounding.

[0038] A slurry bed reactor includes a heating jacket, a stirring paddle, a temperature sensor, a reflux condenser, and a sampling port. Under laboratory conditions, a glass or stainless steel reactor equipped with mechanical stirring, temperature control, and reflux condenser can be used to simulate a slurry bed reactor. After lignin, phenolic reagents, and an acidic catalyst are added to the reactor, a slurry reaction system is formed under stirring. The phenolic reagents serve both as the reaction medium for the lignin liquefaction reaction and as the aromatic component in the subsequent phenolic condensation reaction. The mass concentration of lignin in the system is controlled between 10wt% and 50wt%. If the lignin concentration is below 10wt%, the bio-based substitution ratio is too low, which is not conducive to reducing the amount of petroleum-based phenol used; if the lignin concentration is above 50wt%, the viscosity of the slurry system increases significantly, heat and mass transfer deteriorates, and problems such as incomplete local liquefaction and increased residue content easily occur.

[0039] In this invention, the plant-derived lignin can be one or more of alkali lignin, enzymatically hydrolyzed lignin, organic solvent lignin, lignin extracted from wood pulp black liquor, corn straw lignin, bamboo pulp lignin, and sugarcane bagasse lignin. Preferably, the lignin is vacuum-dried at 60℃-80℃ for 6-12 hours before use to reduce its moisture content to no more than 5wt%, thereby minimizing moisture fluctuations during liquefaction and condensation reactions. The phenolic reagent can be one or more of phenol, p-tert-butylphenol, octylphenol, nonylphenol, dodecylphenol, plant tannins, wood tar creosote, and cashew phenol. Alkylphenols and cashew phenols have longer hydrophobic segments, which can improve the compatibility of the resulting resin with the rubber matrix; wood tar creosote and plant tannins have bio-based sources, which is beneficial for improving the greenness of the resin. The acidic catalyst can be one or more of hydrochloric acid, sulfuric acid, oxalic acid, boric acid, phosphoric acid, phosphotungstic acid, and silicotungstic acid, and the amount of catalyst used is 1wt%-10wt% of the total mass of the liquefaction reaction system.

[0040] After the liquefaction reaction is completed, the liquefied reactants undergo hot solid-liquid separation at 80℃-140℃. Hot solid-liquid separation can be achieved using hot filtration, hot centrifugation, or a filter with an insulated jacket. Since phenolic oil solutions have good fluidity at high temperatures, this reduces filtration resistance and prevents the resinified components from adhering to the filter media after cooling. The unliquefied residue mainly includes insufficiently liquefied lignin particles, ash, and a small amount of insoluble condensates. If the unliquefied residue is not removed, it may become localized over-condensation centers in subsequent condensation reactions, broadening the molecular weight distribution of the resin; in rubber compounding, it may also act as hard particles, affecting the uniformity of dispersion. This invention controls the mass fraction of the unliquefied residue to no more than 2.5 wt%, preferably no more than 1.5 wt%, through hot solid-liquid separation.

[0041] After hot solid-liquid separation, a viscosity modifier is added to the phenolic oil solution for premixing or pre-reaction without the addition of an aldehyde solution. The viscosity modifier is preferably a polyether or polyester compound, specifically polyethylene glycol, polypropylene glycol, ethylene oxide-propylene oxide copolymer, polytetrahydrofuran, polyester polyol, or polycaprolactone diol. The amount of viscosity modifier used is 0.1 wt%-10 wt% of the total mass of the reaction system. In this invention, the viscosity modifier is not simply used as an added plasticizer, but rather it is fully contacted with the phenolic oil solution before the aldehyde condensation reaction, allowing it to participate in regulating the dispersion state of the liquefied lignin component in the phenolic oil and the subsequent condensation reaction rate. This step avoids the problems of rapid thickening of the system, excessively rapid local condensation, and decreased resin thermoplasticity after the addition of the aldehyde solution.

[0042] The aldehyde solution can be one or more of formaldehyde, glyoxal, glutaraldehyde, succinaldehyde, benzaldehyde, p-hydroxybenzaldehyde, furfural, or 5-hydroxymethylfurfural. A 37% (w / w) aqueous formaldehyde solution is preferred in the laboratory. The molar ratio of phenolic components to aldehyde components in the condensation reaction is controlled at 1:0.5-1:1. If the amount of aldehyde component is too low, the resin molecular weight will be insufficient, and the rubber reinforcing effect will be insignificant; if the amount of aldehyde component is too high, the resin is prone to forming an over-condensation structure, increasing the softening point and melt viscosity, which is detrimental to rubber compounding. In this invention, the condensation reaction temperature is preferably controlled at 80℃-105℃, and the reaction time is controlled at 1 hour-5 hours. After the reaction, the resin is dried at 70℃-90℃ and under a vacuum of -0.08MPa to -0.10MPa for 8 hours-16 hours to obtain a lignin-based thermoplastic resin.

[0043] To verify the technical effects of this invention, the applicant tested the resins and their rubber compositions obtained in the examples and comparative examples according to the following test methods. The glass transition temperature was measured using a differential scanning calorimeter under a nitrogen atmosphere at a heating rate of 10°C / min, and the midpoint of the second heating curve was taken as the glass transition temperature. The softening point was tested using the ring and ball method. The melt viscosity was measured using a rotational rheometer at a temperature of 120°C and a shear rate of 10 s⁻¹. The content of unliquefied residue was determined by weighing the dried residue after hot filtration. The resin yield was calculated based on the mass of the resin obtained after vacuum drying relative to the theoretical organic input mass. The rubber mixing test was conducted using a 1.5L internal mixer. The rubber compound formulation was: 60 parts by mass of natural rubber, 40 parts by mass of styrene-butadiene rubber, 50 parts by mass of carbon black N330, 3 parts by mass of zinc oxide, 2 parts by mass of stearic acid, 1.5 parts by mass of antioxidant 4020, 1.8 parts by mass of sulfur, 1.2 parts by mass of accelerator NS, and 8 parts by mass of resin. The vulcanization conditions were 150℃ for 30 minutes. Hardness was tested according to Shore A standards. 300% tensile stress, tensile strength, and elongation at break were tested according to the rubber tensile properties test method. Tear strength was tested using a right-angled specimen. Dynamic mechanical properties were tested using a dynamic thermomechanical analyzer at a frequency of 10 Hz, with a temperature scan range of -60℃ to 80℃. Loss factors at 0℃ and 60℃ were compared.

[0044] Example 1

[0045] This embodiment illustrates a method for preparing lignin-based thermoplastic resins using a mixed phenolic reagent of phenol and p-tert-butylphenol, a composite catalyst of hydrochloric acid and oxalic acid, and polyethylene glycol as a viscosity modifier.

[0046] The slurry-bed reactor was heated to 100°C, and 6.0 g of dried alkali lignin, 14.0 g of phenolic reagent, and 0.40 g of acidic catalyst were added. The phenolic reagent was a mixture of phenol and p-tert-butylphenol in a 1:1 mass ratio; the acidic catalyst was a composite catalyst of hydrochloric acid and oxalic acid in a 2:1 mass ratio. At this point, the mass concentration of lignin in the total lignin and phenolic reagent was 30 wt%, and the amount of catalyst was approximately 2.0 wt% of the total mass of the liquefaction reaction system. Stirring was started at a rate of 300 r / min. After the system formed a homogeneous slurry, the temperature was raised to 130°C, and the reaction was maintained at this temperature for 2 hours, yielding a dark brown liquefied reactant.

[0047] After the liquefaction reaction was completed, the liquefied reactants were maintained at 110℃ and hot-filtered to remove unliquefied residue, yielding a phenolic oil solution. The unliquefied residue was weighed and found to be 0.20 g dry weight, with a residue content of 1.0 wt%. Subsequently, without adding formaldehyde aqueous solution, 1.20 g of polyethylene glycol 2000 was added to the phenolic oil solution, and the mixture was stirred and pre-reacted at 130℃ for 2 hours. After the pre-reaction, the system was cooled to 95℃, and 9.06 g of 37% formaldehyde aqueous solution was slowly added dropwise. After the addition was complete, the mixture was kept at 95℃ for 3 hours. After the reaction, the mixture was naturally cooled to room temperature and then dried at 80℃ under a vacuum of -0.09 MPa for 12 hours to obtain a brownish-brown solid lignin-based thermoplastic resin. The yield of the obtained resin was 89.0%, the glass transition temperature was 48℃, the softening point was 78℃, and the melt viscosity at 120℃ was 2.6 × 10⁻⁶. 5 mPa·s.

[0048] The resin obtained in this embodiment was added to a rubber composition for mixing and vulcanization. Figure 5 As can be seen, the torque of the rubber compound with the resin of this embodiment tends to be stable in the later stage of mixing, and no abnormal torque peaks caused by the difficulty in softening the resin particles occur. The hardness of the vulcanizate is 67 Shore A, the stress at 300% elongation is 11.8 MPa, the tensile strength is 22.6 MPa, and the tear strength is 65 kN / m, indicating that the resin of this embodiment can play a reinforcing role while maintaining processability. The loss factor of the vulcanizate at 0°C is 0.318, and the loss factor at 60°C is 0.118, indicating that the resin of this embodiment has no adverse effect on the wet skid performance and rolling resistance related indicators.

[0049] Example 2

[0050] This embodiment illustrates a method for preparing lignin-based thermoplastic resins using a mixture of nonylphenol and cashew phenol phenolic reagents, phosphotungstic acid catalyst, and polypropylene glycol as a viscosity modifier.

[0051] The slurry bed reactor was heated to 100℃, and 14.0g of enzymatically hydrolyzed lignin, 14.0g of phenolic reagent, and 0.84g of phosphotungstic acid were added. The phenolic reagent was a mixture of nonylphenol and cashew phenol in a mass ratio of 3:2. The lignin mass concentration was 50wt%, and the catalyst dosage was 3.0wt% of the total mass of the liquefaction reaction system. The temperature was raised to 140℃ under stirring at 300r / min, and the reaction was maintained at this temperature for 3 hours to complete the lignin liquefaction. After the reaction, hot filtration was performed at 120℃ to obtain a phenolic oil solution. The dry weight of the unliquefied residue was 0.56g, and the residue content was 2.0wt%.

[0052] 0.56 g of polypropylene glycol 1000 was added to a hot phenolic oil solution, and the mixture was pre-reacted at 140°C for 1.5 hours. It should be noted that in this embodiment, the amount of polypropylene glycol 1000 was controlled to 2 wt% of the total amount of lignin and phenolic reagents to avoid excessive viscosity modifier leading to a decrease in resin reinforcing strength. After the pre-reaction, the system was cooled to 95°C, and 8.46 g of a 37% formaldehyde aqueous solution was added. The mixture was then reacted at 95°C for 3.5 hours. After the reaction, the mixture was dried at 80°C under a vacuum of -0.09 MPa for 12 hours to obtain a brownish-black granular lignin-based thermoplastic resin. The yield of the obtained resin was 91.0%, the glass transition temperature was 42°C, the softening point was 72°C, and the melt viscosity at 120°C was 1.8 × 10⁻⁶. 5 mPa·s.

[0053] The vulcanizate prepared using the resin in this embodiment has a hardness of 66 Shore A, a 300% tensile stress of 11.2 MPa, a tensile strength of 21.9 MPa, and a tear strength of 63 kN / m. Due to the hydrophobic long-chain structure provided by nonylphenol and cashew phenol, the resin exhibits good compatibility with the rubber matrix, a stable mixing torque curve, and no visible resin exudation or hard particles on the surface of the rubber sheet.

[0054] Example 3

[0055] This embodiment illustrates a method for preparing lignin-based thermoplastic resins using a mixture of phenolic reagents (wood tar creosote and dodecylphenol), a composite catalyst of sulfuric acid and boric acid, and an ethylene oxide-propylene oxide copolymer as a viscosity modifier.

[0056] The slurry-bed reactor was heated to 100℃, and 9.33g of bamboo pulp lignin, 14.00g of phenolic reagent, and 0.35g of acidic catalyst were added. The phenolic reagent was a mixture of wood tar creosote and dodecylphenol in a mass ratio of 2:3; the acidic catalyst was a composite catalyst of sulfuric acid and boric acid in a mass ratio of 3:1. The mass concentration of lignin in the total amount of lignin and phenolic reagent was approximately 40wt%, and the amount of catalyst was approximately 1.5wt%. The stirring rate was 300r / min, the temperature was raised to 120℃, and the reaction was maintained at this temperature for 3 hours. During the liquefaction process, the system gradually changed from brownish-yellow to dark brown, indicating that the lignin was gradually converted into phenolic oil components.

[0057] After the liquefaction reaction was completed, hot filtration was performed at 100℃ to remove unliquefied residue. The dry weight of the residue was 0.35 g, and the residue content was 1.5 wt%. 1.17 g of ethylene oxide-propylene oxide copolymer was added to the obtained phenolic oil solution, and the mixture was pre-reacted at 120℃ for 2.5 hours. Then, the mixture was cooled to 100℃, and 10.30 g of a 37% formaldehyde aqueous solution was added. The mixture was then kept at 100℃ for 2.5 hours. After the reaction, vacuum drying yielded a dark brown powdery lignin-based thermoplastic resin. The resin yield was 88.0%, the glass transition temperature was 53℃, the softening point was 83℃, and the melt viscosity at 120℃ was 3.9 × 10⁻⁶. 5 mPa·s.

[0058] The vulcanizate prepared using the resin in this embodiment has a hardness of 68 Shore A, a 300% tensile stress of 12.1 MPa, a tensile strength of 22.4 MPa, and a tear strength of 66 kN / m. These results indicate that when the lignin concentration is increased to 40 wt% and bio-based wood tar creosote is used, the resulting resin still possesses suitable thermoplasticity and stable reinforcing effects for rubber compounding.

[0059] Example 4

[0060] This embodiment illustrates a method for preparing lignin-based thermoplastic resins using a low lignin concentration and polycaprolactone diol.

[0061] 3.0 g of lignin (organic solvent), 17.0 g of phenol, and 0.30 g of phosphoric acid were added to a slurry bed reactor. The lignin concentration was 15 wt%, and the catalyst dosage was approximately 1.5 wt%. The mixture was stirred at 250 r / min and heated to 150 °C for 1.5 hours. After the reaction, the mixture was hot-filtered at 110 °C, yielding a residue with a dry weight of 0.10 g and a residue content of 0.5 wt%. 0.80 g of polycaprolactone diol was added to the phenolic oil solution and pre-reacted at 130 °C for 1 hour. The mixture was then cooled to 90 °C, and 6.60 g of a 37% formaldehyde aqueous solution was added. The reaction was carried out at 90 °C for 4 hours. The mixture was then vacuum-dried at 80 °C for 12 hours to obtain a lignin-based thermoplastic resin. The resin yield was 86.5%, the glass transition temperature was 39 °C, the softening point was 66 °C, and the melt viscosity at 120 °C was 9.5 × 10⁻⁶. 4 mPa·s.

[0062] The vulcanizate prepared using the resin in this embodiment has a hardness of 64 Shore A, a 300% tensile stress of 10.4 MPa, a tensile strength of 21.5 MPa, and a tear strength of 60 kN / m. This embodiment demonstrates that at lower lignin concentrations, the resulting resin has a lower softening point and better flowability, making it more suitable for rubber systems that are sensitive to mixing temperatures or require low heat generation.

[0063] Example 5

[0064] This embodiment illustrates a method for preparing lignin-based thermoplastic resins using a high liquefaction temperature and furfural as an aldehyde solution.

[0065] 8.0 g of alkali lignin, 12.0 g of cashew phenol, and 0.80 g of silicotungstic acid were added to a reactor, with a lignin concentration of 40 wt% and a catalyst dosage of 4.0 wt%. The mixture was heated to 160 °C under stirring at 350 r / min and reacted for 2 hours. After the reaction, the mixture was hot-filtered at 130 °C, yielding a residue with a dry weight of 0.24 g and a residue content of 1.2 wt%. 1.00 g of polytetrahydrofuran was added to the phenolic oil solution, and the mixture was pre-reacted at 140 °C for 2 hours. Then, the mixture was cooled to 100 °C, and furfural was added to achieve a molar ratio of phenolic to aldehyde components of approximately 1:0.70. The mixture was then reacted at 100 °C for 4 hours. After the reaction, the mixture was vacuum-dried at 85 °C for 12 hours to obtain a lignin-based thermoplastic resin. The yield of the obtained resin was 87.8%, the glass transition temperature was 57 °C, the softening point was 88 °C, and the melt viscosity at 120 °C was 5.2 × 10⁻⁶. 5 mPa·s.

[0066] The vulcanizate prepared using the resin in this embodiment has a hardness of 69 Shore A, a 300% tensile stress of 12.4 MPa, a tensile strength of 22.1 MPa, and a tear strength of 64 kN / m. This embodiment demonstrates that when furfural, a bio-based aldehyde, is used instead of formaldehyde, a thermoplastic resin suitable for rubber reinforcement can still be obtained.

[0067] Example 6

[0068] This embodiment illustrates a method for preparing a low softening point lignin-based thermoplastic resin using a shorter condensation time.

[0069] 6.0 g of alkali lignin, 14.0 g of phenol, and 0.50 g of oxalic acid were added to a reactor and reacted at 130 °C for 2 hours. After liquefaction, the mixture was hot-filtered at 100 °C, yielding a residue with a dry weight of 0.22 g and a residue content of 1.1 wt%. 0.60 g of polyethylene glycol 1000 was added to the phenolic oil solution and pre-reacted at 125 °C for 1 hour. The mixture was then cooled to 85 °C, and 7.20 g of a 37% formaldehyde aqueous solution was added. A condensation reaction was carried out at 85 °C for 1.5 hours. The mixture was then vacuum-dried at 80 °C for 12 hours to obtain a lignin-based thermoplastic resin. The yield of the obtained resin was 84.2%, the glass transition temperature was 35 °C, the softening point was 58 °C, and the melt viscosity at 120 °C was 6.8 × 10⁻⁶. 4 mPa·s.

[0070] The vulcanizate prepared using the resin in this embodiment has a hardness of 63 Shore A, a 300% tensile stress of 9.8 MPa, a tensile strength of 20.8 MPa, and a tear strength of 58 kN / m. This embodiment illustrates that by lowering the condensation reaction temperature and shortening the condensation time, a lignin-based thermoplastic resin with a low softening point and good flowability can be obtained, making it suitable for rubber compound systems requiring good mixing flowability.

[0071] Comparative Example 1

[0072] This comparative example illustrates the effect of not performing hot solid-liquid separation on resin properties and rubber reinforcement.

[0073] Except for the absence of hot filtration after the liquefaction reaction, the remaining steps were the same as in Example 1. The liquefied reactants were directly added to polyethylene glycol 2000 and subsequently subjected to formaldehyde condensation. A small amount of insoluble particles were visible in the resulting resin, and the resin appearance was uneven after drying. Testing showed that the resin residue content was 5.8 wt%, the glass transition temperature was 61°C, the softening point was 96°C, and the melt viscosity at 120°C was 1.7 × 10⁻⁶. 6 mPa·s.

[0074] After the resin was added to the rubber composition, the mixing curve showed significant torque fluctuations, and the rubber sheet surface had a small number of granular bumps. The vulcanized rubber had a hardness of 66 Shore A, a 300% tensile stress of 10.2 MPa, a tensile strength of 18.7 MPa, and a tear strength of 52 kN / m. Compared with Example 1, the tensile strength and tear strength of Comparative Example 1 were significantly reduced, indicating that unliquefied residue affects the uniformity of resin dispersion and reinforcing effect in rubber.

[0075] Comparative Example 2

[0076] This comparative example illustrates the effect of not adding a viscosity modifier on the thermoplasticity and processability of the resin.

[0077] Except for the omission of polyethylene glycol 2000, the remaining steps were the same as in Example 1. The resulting resin yield was 90.2%, with a glass transition temperature of 69°C, a softening point of 105°C, and a melt viscosity of 4.8 × 10⁻⁶ at 120°C. 6 The resin is brittle at room temperature and the pulverized particles are quite hard.

[0078] When this resin was used in rubber compounding, the torque was higher in the later stages of compounding, and the discharge temperature was about 6°C higher than in Example 1. The vulcanizate had a hardness of 69 Shore A, a 300% tensile stress of 11.0 MPa, a tensile strength of 19.4 MPa, a tear strength of 55 kN / m, and a loss factor of 0.136 at 60°C. The results indicate that without the addition of a viscosity modifier, the resin's softening point and melt viscosity are relatively high. While this can improve hardness, it is detrimental to the uniform dispersion of the resin in the compound, leading to a decrease in the overall reinforcing effect.

[0079] Comparative Example 3

[0080] This comparative example illustrates the effect of simultaneously adding viscosity modifier and aldehyde solution on resin performance.

[0081] Except for the simultaneous addition of polyethylene glycol 2000 and formaldehyde aqueous solution, the remaining steps were the same as in Example 1. The resulting resin had a glass transition temperature of 64°C, a softening point of 98°C, and a melt viscosity of 2.9 × 10⁻⁶ at 120°C. 6 mPa·s. During the reaction, the viscosity of the system increased significantly about 40 minutes after the addition of the formaldehyde aqueous solution, and the stirring resistance increased, indicating that the local condensation rate was relatively fast.

[0082] The vulcanizate prepared using this resin has a hardness of 67 Shore A, a 300% tensile stress of 10.7 MPa, a tensile strength of 19.9 MPa, and a tear strength of 56 kN / m. Compared with Example 1, although Comparative Example 3 also added a viscosity modifier, it failed to effectively control the molecular weight growth rate in the early stage of the condensation reaction because it did not undergo pre-reaction before aldehyde condensation. Therefore, the melt viscosity of the resulting resin was still relatively high, and the rubber reinforcing effect was lower than that of Example 1.

[0083] Comparative Example 4

[0084] This comparative example illustrates the effect of directly condensing ordinary lignin with phenol and formaldehyde without a liquefaction step.

[0085] 6.0 g of alkali lignin, 14.0 g of phenol, 0.40 g of acidic catalyst, 1.20 g of polyethylene glycol 2000, and 9.06 g of 37% formaldehyde aqueous solution were directly added to a reactor and reacted at 95°C for 5 hours, followed by vacuum drying. The resulting product was heterogeneous in appearance and contained obvious insoluble lignin particles. Testing showed a residue content of 12.5 wt%, a glass transition temperature of 73°C, a softening point of 112°C, and a melt viscosity at 120°C exceeding 1.0 × 10⁻⁶. 7 mPa·s.

[0086] When this resin is used in rubber compounding, the rubber compound exhibits uneven surface dispersion and significant fluctuations in the mixing torque curve. The vulcanized rubber has a hardness of 65 Shore A, a 300% tensile stress of 9.5 MPa, a tensile strength of 17.8 MPa, and a tear strength of 48 kN / m. These results indicate that lignin, without phenolic liquefaction, is difficult to fully participate in phenolic condensation and to form a uniform reinforcing network within the rubber matrix.

[0087] Comparative Example 5

[0088] This comparative example illustrates the effect of excessive aldehyde content on the thermoplasticity of the resin.

[0089] Except for increasing the amount of formaldehyde aqueous solution to achieve a molar ratio of phenolic components to formaldehyde components of approximately 1:1.25, the remaining steps were the same as in Example 1. The resulting resin had a glass transition temperature of 82°C, a softening point of 118°C, and a melt viscosity of 8.6 × 10⁻⁶ at 120°C. 6 mPa·s. This resin softens slowly at the rubber mixing temperature, and the mixing torque increases significantly.

[0090] The vulcanizate prepared using this resin has a hardness of 70 Shore A, a 300% tensile stress of 11.4 MPa, a tensile strength of 18.9 MPa, and a tear strength of 53 kN / m. Although the hardness is high, the tensile strength and tear strength are lower than those of Example 1, indicating that excessive aldehyde components can lead to excessive resin condensation, resulting in a decrease in its thermoplasticity and rubber dispersibility.

[0091] Summary of performance test results

[0092] Table 1 lists the main properties of the resins obtained in Examples 1-6 and Comparative Examples 1-5. From Table 1 and in conjunction with... Figure 2 As can be seen, the glass transition temperature of the resin obtained in the embodiments of the present invention is between 35℃ and 57℃, the softening point is between 58℃ and 88℃, and the melt viscosity at 120℃ is 6.8 × 10⁻⁶. 4 mPa·s-5.2×10 5 The values ​​of mPa·s are all within the thermoplastic window suitable for rubber compounding. In contrast, Comparative Examples 1-5, due to the lack of residue removal, the absence of viscosity modifiers, improper order of viscosity modifier addition, lack of liquefaction, or excessive aldehyde component dosage, all exhibited problems such as increased residue content, increased softening point, or significantly increased melt viscosity.

[0093]

[0094] Table 2 lists the properties of the rubber compositions with the addition of different resins. (Based on Table 2 and...) Figure 4 As can be seen, the resins obtained in Examples 1-6 can all improve the hardness, tensile stress, tensile strength, and tear strength of the vulcanizate, with minimal performance fluctuations. This indicates that different combinations of phenolic reagents, catalysts, viscosity modifiers, and aldehyde solutions within the scope of the claims of this invention can achieve essentially the same reinforcing effect. Although some samples in Comparative Examples 1-5 can improve hardness, their tensile strength, tear strength, or dynamic properties are significantly reduced, indicating insufficient uniformity of reinforcement and poor processability.

[0095]

[0096] As shown in Table 2, Examples 1-6 all exhibited significant reinforcing effects compared to the blank compound. Specifically, the hardness increased by 3-9 Shore A units, the 300% tensile stress increased by 1.2 MPa-3.8 MPa, the tensile strength increased by 1.2 MPa-3.0 MPa, and the tear strength increased by 8 kN / m-16 kN / m. While the degree of reinforcement varied slightly among the examples due to differences in lignin concentration, phenolic reagents, and viscosity modifiers, the overall trend was consistent, indicating that the technical solution of this invention has good process adaptability and repeatability. In the comparative examples, hardness sometimes increased, but tensile strength and tear strength did not increase simultaneously. In particular, Comparative Example 4, due to the high residue content caused by unliquefied lignin, had lower tensile and tear strengths than the blank compound, indicating that simply adding or directly condensing lignin cannot achieve the technical effects of this invention.

[0097] Combination Figure 3 The torque variation curves of the mixing process show that the rubber compounds in Examples 1-6 initially experienced a brief increase in torque after the addition of resin, followed by a gradual decrease and stabilization as the resin softened and dispersed. The rubber compounds in Comparative Examples 2, 3, and 5 maintained relatively high torque in the later stages of mixing, indicating insufficient resin softening and dispersion. Comparative Examples 1 and 4 contained insoluble residues or unliquefied lignin particles, resulting in significant fluctuations in their torque curves. These results demonstrate that the present invention, through hot slag removal and pre-reaction with a viscosity modifier, can improve the melt dispersion behavior of resin during rubber mixing.

[0098] Combination Figure 5 The dynamic mechanical property results show that, while improving the reinforcing performance of rubber, Examples 1-6 did not significantly increase the loss factor at 60°C; in some examples, it was even slightly lower than the blank compound. This indicates that the resin of the present invention did not experience a significant increase in hysteretic heat generation due to excessive crosslinking or poor dispersion. Comparative Examples 2, 3, and 5, due to their higher softening points and melt viscosities, exhibited insufficient uniformity of resin dispersion in the rubber, resulting in increased loss factors at 60°C. Comparative Example 4, with its higher proportion of unliquefied lignin particles, showed the highest dynamic loss. These results further demonstrate that the lignin-based thermoplastic resin obtained in this invention is more suitable for tire rubber reinforcement applications.

[0099] In summary, the embodiments of the present invention demonstrate that, within the scope defined by the claims, lignin-based thermoplastic resins with glass transition temperatures, softening points, and melt viscosities within suitable ranges for rubber compounding can be prepared using lignin from different sources, different phenolic reagents, different acidic catalysts, different viscosity modifiers, and different aldehyde solutions. When the resulting resin is added to a rubber composition, it can improve hardness, tensile stress, tensile strength, and tear strength, while maintaining good dynamic properties. Comparative examples demonstrate that omitting the liquefaction step, omitting hot solid-liquid separation, omitting the viscosity modifier, changing the order of viscosity modifier addition, or using an excessive amount of aldehyde component will all lead to an increase in resin residue content, softening point, or melt viscosity, thereby reducing the dispersibility and overall reinforcing effect of rubber compounding. Therefore, the process combination of liquefaction, slag removal, viscosity modifier pre-reaction, and aldehyde condensation in the present invention is not simply parallel, but rather works together to enhance lignin reactivity, resin thermoplasticity, and rubber reinforcing uniformity, achieving a balance between green raw material utilization, processability, and reinforcing performance that is difficult to simultaneously achieve with existing technologies.

[0100] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A method for synthesizing a lignin-based thermoplastic resin for rubber reinforcement, characterized in that, Includes the following steps: S1, plant-derived lignin, phenolic reagents and acidic catalysts are added to a slurry bed reactor to form a slurry reaction system with a mass concentration of 10wt%-50wt% in the phenolic reagents, and the reaction is carried out at 100℃-250℃ for 1 hour-8 hours to cause phenolization and liquefaction of lignin, and liquefied reactants containing phenolic oil are obtained. S2, perform hot solid-liquid separation on the liquefied reactants to remove unliquefied residue and obtain a phenolic oil solution; S3, without adding aldehyde solution, add phenol and 0.1wt%-10wt% viscosity modifier to the phenolic oil solution, and pre-react at 100℃-150℃ for 1 hour-3 hours, so that the viscosity modifier is pre-mixed or pre-reacted with the liquefied lignin component in the phenolic oil to obtain the viscosity-adjusted phenolic oil reaction solution. S4, the viscosity-adjusted phenolic oil reaction solution is cooled to 80℃-105℃, an aldehyde solution is added to carry out a condensation reaction for 1 hour to 5 hours, and then vacuum dried to obtain a lignin-based thermoplastic resin for rubber reinforcement. In the condensation reaction, the molar ratio of phenolic components to aldehyde components is 1:0.5-1:1, and the resulting lignin-based thermoplastic resin has a glass transition temperature of 30℃-80℃, a softening point of 50℃-110℃, and a melt viscosity of 10. 4 mPa·s⁻¹⁰ 8 mPa·s.

2. The synthesis method according to claim 1, characterized in that, The phenolic reagent is one or more of phenol, alkylphenol, and natural polyphenols; the alkylphenol is selected from one or more of p-tert-butylphenol, octylphenol, nonylphenol, and dodecylphenol; the natural polyphenol is selected from one or more of plant tannins, wood tar creosote, and cashew nut phenol. And / or, the acidic catalyst is one or more of hydrochloric acid, sulfuric acid, oxalic acid, boric acid, phosphoric acid, phosphotungstic acid, and silicotungstic acid, and the amount of the acidic catalyst is 1wt%-10wt% of the total mass of the liquefaction reaction system.

3. The synthesis method according to claim 1, characterized in that, The slurry reaction system described in S1 reacts under stirring conditions, with a stirring rate of 100 r / min to 600 r / min; the liquefaction reaction temperature is 120℃ to 160℃, and the liquefaction reaction time is 1.5 hours to 4 hours. And / or, the hot solid-liquid separation described in S2 is carried out at 80℃-140℃ to separate the unliquefied residue from the phenolic oil solution, thereby reducing the impact of unliquefied lignin particles on the subsequent condensation reaction and the dispersibility of rubber compounding. And / or, the molar ratio of phenolic oil to phenol in S3 is 1:10-10:1, and the phenol is used to adjust the content of condensable phenolic hydroxyl groups in the phenolic oil reaction solution and the rate of subsequent condensation reaction.

4. The synthesis method according to claim 1, characterized in that, The viscosity modifier is a polyether compound or a polyester compound; the polyether compound is selected from at least one of polyethylene glycol, polypropylene glycol, ethylene oxide-propylene oxide copolymer, and polytetrahydrofuran; the polyester compound is selected from at least one of polyester polyol and polycaprolactone diol. And / or, the aldehyde solution is formaldehyde, aliphatic dialdehyde, aromatic aldehyde, or bio-based aldehyde; the aliphatic dialdehyde is selected from one or more of glyoxal, glutaraldehyde, and succinaldehyde; the aromatic aldehyde is selected from one or more of benzaldehyde and p-hydroxybenzaldehyde; the bio-based aldehyde is selected from one or more of furfural and 5-hydroxymethylfurfural.

5. The synthesis method according to claim 1, characterized in that, The vacuum drying temperature described in S4 is 70℃-90℃, the time is 8 hours-16 hours, and the vacuum degree is -0.08MPa to -0.10MPa.

6. A lignin-based thermoplastic resin for rubber reinforcement, characterized in that, It is prepared by the synthesis method described in any one of claims 1 to 5.

7. The lignin-based thermoplastic resin according to claim 6, characterized in that, The lignin-based thermoplastic resin can soften and disperse in the rubber matrix at the rubber mixing temperature, and participate in the formation of the rubber reinforcing network during vulcanization, thereby improving the hardness, modulus, tear strength or abrasion resistance of the rubber.

8. The application of a lignin-based thermoplastic resin in the preparation of tire rubber reinforcing materials, characterized in that, The lignin-based thermoplastic resin is the lignin-based thermoplastic resin according to claim 6 or 7.

9. The application according to claim 8, characterized in that, The tire rubber reinforcement material is used in tread rubber, sidewall rubber, gusset rubber, bead reinforcement rubber, or cord adhesive.

10. A rubber composition, characterized in that, It comprises 100 parts by weight of a rubber matrix and 1-20 parts by weight of the lignin-based thermoplastic resin as described in claim 6 or 7; the rubber matrix is ​​one or more of natural rubber, styrene-butadiene rubber, cis-butadiene rubber, isoprene rubber, nitrile rubber, and brominated butyl rubber.

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