Ionic liquid modified phenolic resin and application thereof as rubber additive

Abstract

The invention provides an ionic liquid modified phenolic resin and application thereof as a rubber additive. The ionic liquid modified phenolic resin is prepared by reacting a phenolic compound, an ionic liquid, an aldehyde compound and an optional modifier. According to the invention, the ionic liquid is modified on the phenolic resin used as rubber tackifying resin or reinforcing resin, so that the interaction between the resin additive and the filler is enhanced, the adsorption of the filler to a vulcanization system is reduced, and the purpose of improving the vulcanization performance and the mechanical performance of the rubber material is achieved on the basis of not influencing the functionality of the phenolic resin.

Description

Technical Field

[0001] The invention belongs to the field of rubber additives and relates to ionic liquid modified phenolic resin and application thereof as a rubber additive. Background Art

[0002] Phenolic resins are important additives in the rubber tire industry. Two alkylphenol-formaldehyde resins, tert-butylphenol-formaldehyde resin and tert-octylphenol-formaldehyde resin, are used as tackifiers to improve the adhesion between uncured rubber sheets. It is generally believed that the tackifying mechanism of alkylphenol-formaldehyde resins is that the alkylphenol-formaldehyde resin migrates to the rubber surface, forming a hydrogen-bonded crosslinked network of phenolic hydroxyl groups at the interface between the two films. The alkyl group located opposite the phenolic hydroxyl group controls the compatibility of the phenolic resin with the rubber, allowing the phenolic resin to continuously migrate from the rubber interior to the surface.

[0003] Current technology focuses on preparing modified alkylphenol-formaldehyde resins to improve the viscosity and mechanical properties of the resins. For example, unsaturated bonds are modified on alkylphenol-formaldehyde resins to allow them to participate in the cross-linking of rubber and improve the long-term viscosity of the rubber. Phenol-formaldehyde resins modified with tall oil or cashew nut oil are used as reinforcing resins, and work synergistically with reinforcing fillers such as carbon black and white carbon black to improve the various physical properties of vulcanized rubber. The unreacted sites of phenol in the reinforcing resin are cross-linked during the rubber processing process, and the resin network has a reinforcing effect; the main purpose of using cashew nut oil and tall oil modifiers is to modify the phenolic resin with long hydrocarbon groups to improve the compatibility between the resin and rubber.

[0004] However, tire rubber has a complex composition and contains a large amount of fillers, sulfur and other additives. Conventional tackifying resins rarely take into account the interactions between different additives, and their functionality is limited. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention modifies a phenolic resin, typically used as a rubber tackifying or reinforcing resin, with an ionic liquid, 1-allyl-3-methylimidazolium chloride. This enhances the interaction between the resin additive and the filler, while simultaneously reducing the filler's adsorption to the vulcanization system. This improves the vulcanization and mechanical properties of the rubber compound without affecting the functionality of the phenolic resin. When the ionic liquid-modified phenolic resin of the present invention is used in tire rubber, the ionic liquid, 1-allyl-3-methylimidazolium chloride, interacts with fillers such as carbon black and white carbon black, shortening the cure time and improving the crosslinked mechanical properties.

[0006] In order to achieve the above object, the present invention provides an ionic liquid modified phenolic resin, wherein the ionic liquid modified phenolic resin is formed by reacting a phenolic compound, an ionic liquid, an aldehyde compound and an optional modifier;

[0007] The phenolic compound has a structure shown in Formula I:

[0008]

[0009] In formula I, R1 is selected from H and C1-C20 alkyl;

[0010] The ionic liquid is a compound of formula II:

[0011]

[0012] The modifier is selected from one or both of cashew nut oil and tall oil.

[0013] In one or more embodiments, in Formula I, R1 is selected from H and C1-C10 alkyl; preferably, R1 is selected from H, t-octyl and t-butyl.

[0014] In one or more embodiments, the aldehyde compound is selected from one or more of formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, hexanal, benzaldehyde and furfural, preferably formaldehyde.

[0015] In one or more embodiments, in the raw materials of the ionic liquid-modified phenolic resin, the molar ratio of the phenolic compound to the ionic liquid is 1:(0.01-0.1).

[0016] In one or more embodiments, in the raw materials of the ionic liquid-modified phenolic resin, the molar ratio of the phenolic compound to the aldehyde compound is 1:(0.6-0.9).

[0017] In one or more embodiments, in the raw materials of the ionic liquid-modified phenolic resin, the molar ratio of the phenolic compound to the modifier is 1:(0-0.2).

[0018] In one or more embodiments, in the raw materials of the ionic liquid-modified phenolic resin, the molar ratio of the phenolic compound, the ionic liquid, the aldehyde compound and the modifier is 1:(0.01-0.1):(0.6-0.9):(0-0.2).

[0019] In one or more embodiments, the raw material of the ionic liquid modified phenolic resin does not include a modifier, and the molar ratio of the phenolic compound, the ionic liquid and the aldehyde compound in the raw material of the ionic liquid modified phenolic resin is 1: (0.01-0.05): (0.65-0.8).

[0020] In one or more embodiments, the raw materials of the ionic liquid modified phenolic resin include a modifier, and the molar ratio of the phenolic compound, the ionic liquid, the aldehyde compound and the modifier in the raw materials of the ionic liquid modified phenolic resin is 1: (0.01-0.05): (0.65-0.8): (0.05-0.15).

[0021] In one or more embodiments, the ionic liquid-modified phenolic resin is formed by reacting a phenolic compound, an ionic liquid, an aldehyde compound, and a modifier, and the phenolic compound is phenol.

[0022] In one or more embodiments, the ionic liquid-modified phenolic resin is formed by reacting a phenolic compound, an ionic liquid, and an aldehyde compound, and the phenolic compound comprises a compound of formula IA and optionally phenol:

[0023]

[0024] In formula IA, R2 is selected from C1-C20 alkyl, preferably tert-octyl and tert-butyl; preferably, the mass fraction of phenol in the phenolic compound is 0 to 20%.

[0025] The present invention also provides a method for preparing the ionic liquid-modified phenolic resin described in any embodiment of the present invention, the method comprising:

[0026] (1) subjecting the phenolic compound to a Friedel-Crafts reaction with the ionic liquid to obtain a compound of formula III, wherein R1 is selected from H and a C1-C20 alkyl group:

[0027]

[0028] (2) subjecting the phenolic compound, the compound of formula III and the aldehyde compound to a condensation reaction, and optionally adding a modifier to the reaction system for reaction to obtain the ionic liquid modified phenolic resin.

[0029] In one or more embodiments, the reaction of step (1) and step (2) is carried out in the presence of an acidic catalyst; the acidic catalyst is preferably selected from one or more of p-toluenesulfonic acid, methanesulfonic acid, benzenesulfonic acid, benzene disulfonic acid, dodecylbenzenesulfonic acid, hydrochloric acid, sulfuric acid and phosphoric acid, more preferably p-toluenesulfonic acid; the amount of the acidic catalyst is preferably 0.2 mol% to 1 mol% of the amount of the phenolic compound.

[0030] In one or more embodiments, the reaction temperature of step (1) is 50 to 180° C., and the reaction time is 10 min to 5 h.

[0031] In one or more embodiments, the polycondensation reaction temperature in step (2) is 100-140° C., the polycondensation reaction time is 10 min-12 h, and after adding the modifier, the reaction temperature is 120-180° C., and the reaction time is 1 h-12 h.

[0032] The present invention also provides a method for preparing the ionic liquid-modified phenolic resin described in any embodiment of the present invention, the method comprising:

[0033] (1') subjecting the phenolic compound to a condensation polymerization reaction with an aldehyde compound to obtain a phenolic resin;

[0034] (2') reacting the phenolic resin with the ionic liquid and an optionally added modifier to obtain the ionic liquid-modified phenolic resin.

[0035] In one or more embodiments, the reaction of step (1') and step (2') is carried out in the presence of an acidic catalyst; the acidic catalyst is preferably selected from one or more of p-toluenesulfonic acid, methanesulfonic acid, benzenesulfonic acid, benzene disulfonic acid, dodecylbenzenesulfonic acid, hydrochloric acid, sulfuric acid and phosphoric acid, more preferably p-toluenesulfonic acid; the amount of the acidic catalyst is preferably 0.2 mol% to 1 mol% of the amount of the phenolic compound.

[0036] In one or more embodiments, the reaction temperature of step (1') is 100-140°C, and the reaction time is 10 min-12 h.

[0037] In one or more embodiments, the reaction temperature of step (2') is 120-180°C, and the reaction time is 1 hour to 12 hours.

[0038] The present invention also provides a rubber composition, comprising a diene elastomer and the ionic liquid-modified phenolic resin described in any embodiment herein; preferably, the ionic liquid-modified phenolic resin serves as a tackifying resin or a reinforcing resin of the rubber composition; preferably, in the rubber composition, the mass ratio of the diene elastomer to the ionic liquid-modified phenolic resin is 100:(1 to 20).

[0039] The present invention also provides use of the ionic liquid-modified phenolic resin described in any embodiment herein in improving the vulcanization properties and / or mechanical properties of rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the preparation process of ionic liquid modified reinforcing resin in some embodiments of the present invention. DETAILED DESCRIPTION

[0041] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0042] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0043] Herein, “comprising,” “including,” “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of,” for example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to have been disclosed herein.

[0044] Herein, all features such as values, amounts, amounts, and concentrations defined in numerical ranges or percentage ranges are for brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0045] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0046] Herein, when describing embodiments or examples, it should be understood that they are not intended to limit the present invention to these embodiments or examples. On the contrary, all alternatives, modifications and equivalents of the methods and materials described herein are encompassed within the scope defined by the claims.

[0047] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0048] The present invention uses a phenolic resin modified with 1-allyl-3-methylimidazolium chloride represented by Formula II as a tackifying resin or reinforcing resin for a rubber composition:

[0049]

[0050] Formula II compound is a kind of ionic liquid, has terminal alkenyl group, nitrogen heteroatom and ionic bond.Ionic liquid suitable for the present invention has terminal alkenyl group, is therefore also referred to as alkenyl ionic liquid.The present invention finds that the interaction of the ionic liquid shown in formula II and filler causes the positive cure time to shorten, mechanical property improves.Compared to some other ionic liquids, formula II compound shows the effect of better improving rubber compound mechanical property and vulcanization property.

[0051] The ionic liquid modified phenolic resin of the present invention is prepared by reacting a phenolic compound, a compound of formula II, an aldehyde compound and an optional modifier, wherein the modifier is selected from one or both of cashew nut oil and tall oil.

[0052] The phenolic compounds suitable for use in the present invention have the structure shown in Formula I:

[0053]

[0054] In formula I, R1 is selected from H and C1-C20 alkyl.

[0055] In the present invention, an alkyl group refers to a linear or branched monovalent saturated hydrocarbon group. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, tert-octyl, tert-octyl, and the like. In some embodiments, in Formula I, R1 is selected from H and C1-C10 alkyl, for example, R1 can be selected from H, tert-butyl, and tert-octyl.

[0056] The aldehyde compound suitable for the present invention can be one or more selected from formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, hexanal, benzaldehyde and furfural. In some preferred embodiments, the aldehyde compound used in the present invention is formaldehyde.

[0057] In the present invention, the molar ratio of the phenolic compound to the ionic liquid in the raw materials of the ionic liquid-modified phenolic resin can be 1:(0.01-0.1), preferably 1:(0.01-0.05).

[0058] In the present invention, the molar ratio of the phenolic compound to the aldehyde compound in the raw materials of the ionic liquid-modified phenolic resin can be 1:(0.6-0.9), preferably 1:(0.65-0.8).

[0059] In the present invention, in the raw materials of the ionic liquid-modified phenolic resin, the molar ratio of the phenolic compound to the modifier can be 1:(0-0.2), for example, 1:(0-0.15).

[0060] As the raw material of the ionic liquid modified phenolic resin, the molar ratio of the phenolic compound, the ionic liquid, the aldehyde compound and the modifier can be 1: (0.01-0.1): (0.6-0.9): (0-0.2), preferably 1: (0.01-0.05): (0.65-0.8): (0-0.15).

[0061] In some embodiments, the raw materials for the ionic liquid-modified phenolic resin include a modifier, and the molar ratio of the phenolic compound to the modifier can be 1:(0.02-0.2), preferably 1:(0.05-0.15), for example 1:(0.07-0.14). In some embodiments, the raw materials for the ionic liquid-modified phenolic resin do not include a modifier.

[0062] In some embodiments, the ionic liquid-modified phenolic resin has the structure of Formula IV:

[0063]

[0064] In Formula IV, R3 is a group derived from an ionic liquid, for example, a group derived from 1-allyl-3-methylimidazolium chloride, R4 is one or more selected from H, R1, and a group derived from a modifier (for example, tall oil and cashew oil), and x and y are the number of repeating units.

[0065] In the present invention, when the ionic liquid modified phenolic resin is a reinforcing resin, its raw material preferably contains a modifier. When the ionic liquid modified phenolic resin is a tackifying resin, its raw material preferably does not contain a modifier.

[0066] In some embodiments, the ionic liquid-modified phenolic resin is a reinforcing resin. In Formula I, R1 is H, that is, the ionic liquid-modified phenolic resin is formed by reacting phenol, a compound of Formula II, an aldehyde compound, and an optional modifier. In some preferred embodiments, the ionic liquid-modified phenolic resin as a reinforcing resin is formed by reacting phenol, a compound of Formula II, an aldehyde compound, and a modifier. The molar ratio of the phenolic compound, the ionic liquid, the aldehyde compound, and the modifier is preferably 1: (0.01-0.1): (0.6-0.9): (0.02-0.2), more preferably 1: (0.01-0.05): (0.65-0.8): (0.05-0.15).

[0067] In some embodiments, the ionic liquid-modified phenolic resin is a tackifying resin, and the ionic liquid-modified phenolic resin is formed by reacting a phenolic compound, a compound of formula II, an aldehyde compound, and an optional modifier, wherein the phenolic compound includes an alkylphenol represented by formula IA and optionally phenol:

[0068]

[0069] In Formula IA, R2 is selected from a C1-C20 alkyl group, preferably a C1-C10 alkyl group, such as tert-octyl and tert-butyl. In some embodiments, the ionic liquid-modified phenolic resin used as a tackifying resin is formed by reacting a phenolic compound, a compound of Formula II, and an aldehyde compound, wherein the phenolic compound comprises an alkylphenol of Formula IA and optionally phenol. In Formula IA, R2 is selected from a C1-C20 alkyl group, preferably a C1-C10 alkyl group, such as tert-octyl and tert-butyl. In some embodiments, the ionic liquid-modified phenolic resin used as a tackifying resin is formed by reacting an alkylphenol of Formula IA, phenol, a compound of Formula II, and an aldehyde compound. In Formula IA, R2 is selected from a C1-C20 alkyl group, preferably a C1-C10 alkyl group, such as tert-octyl and tert-butyl. When the phenolic compound comprises an alkylphenol and optionally phenol, the mass fraction of phenol in the phenolic compound can be 0-20%, such as 1-20%, 5-15%, 8%, 10%, or 12%.

[0070] The ionic liquid modified phenolic resin of the present invention can be prepared by various methods.

[0071] In some embodiments, the present invention uses the following method to prepare an ionic liquid modified phenolic resin:

[0072] (1) First, a phenolic compound represented by Formula I or Formula IA is subjected to a Friedel-Crafts reaction with an ionic liquid represented by Formula II to obtain a compound represented by Formula III:

[0073]

[0074] In formula III, R1 is selected from H and C1-C20 alkyl;

[0075] (2) The phenolic compound, the compound of formula III and the aldehyde compound are subjected to a condensation reaction, and a modifier is optionally added to the reaction system to react to obtain the ionic liquid modified phenolic resin of the present invention.

[0076] When the phenolic compound and the ionic liquid are subjected to the Friedel-Crafts reaction, it is preferred to add an excess of the phenolic compound so that the terminal olefin groups of the ionic liquid are completely reacted. For example, all the phenolic compound required for preparing the ionic liquid-modified phenolic resin can be added. The Friedel-Crafts reaction of the phenolic compound and the ionic liquid can be carried out in the presence of an acidic catalyst, such as p-toluenesulfonic acid. The reaction temperature can be 50-180°C, such as 100°C, 120°C, or 140°C, and the reaction time can be 10 minutes to 5 hours, such as 30 minutes, 60 minutes, 90 minutes, 2 hours, or 4 hours. The reaction in step (2) can be carried out in the presence of an acidic catalyst. The acidic catalyst suitable for the present invention can be any of various known acids that can be used as catalysts for preparing phenolic resins, including organic acids and inorganic acids, such as p-toluenesulfonic acid, methanesulfonic acid, benzenesulfonic acid, benzene disulfonic acid, dodecylbenzenesulfonic acid, hydrochloric acid, sulfuric acid, phosphoric acid, etc., preferably p-toluenesulfonic acid. The amount of the acidic catalyst used can be 0.2 mol% to 1 mol% of the amount of the phenolic compound. When carrying out the polycondensation reaction of step (2), a phenolic compound can be optionally added to the system after the reaction of step (1) as needed, and then an aldehyde compound can be slowly added to carry out the polycondensation reaction. The temperature of the polycondensation reaction can be 100-140°C, for example, 120°C, and the reaction time can be 10 min-12 h, for example, 30 min, 1 h, 2 h, or 6 h. After the polycondensation reaction, a modifier can be optionally added to the reaction system as needed to carry out the reaction. The reaction temperature can be 120-180°C, for example, 150°C, and the reaction time can be 1 h-12 h, for example, 2 h, 3 h, 4 h, or 6 h. After the reaction of step (2) is completed, water and free phenolic compounds can be removed by distillation under reduced pressure, and then a base can be added to quench the reaction.

[0077] like Figure 1 As shown in (a), in some embodiments, the ionic liquid-modified phenolic resin of the present invention as a reinforcing resin is synthesized by the following method: phenol and an acidic catalyst are melted, and an alkenyl ionic liquid is added for reaction; then an aldehyde compound is added dropwise for polycondensation; a modifier (tall oil and / or cashew oil) is added for reaction; water and free phenol are removed by distillation under reduced pressure; and a base is added for neutralization, quenching the reaction and discharging.

[0078] In other embodiments, the present invention adopts the following method to prepare ionic liquid modified phenolic resin:

[0079] (1') subjecting a phenolic compound to a polycondensation reaction with an aldehyde compound to obtain a phenolic resin;

[0080] (2') reacting a phenolic resin with an ionic liquid and an optionally added modifier to obtain an ionic liquid-modified phenolic resin.

[0081] The polycondensation reaction of step (1') can be carried out in the presence of an acidic catalyst. The temperature of the polycondensation reaction can be 100-140°C, for example, 120°C, and the reaction time can be 10 min-12 h, for example, 30 min, 1 h, 2 h, or 6 h. When carrying out the polycondensation reaction, the phenolic compound and the acidic catalyst can be heated to the reaction temperature first, and then the aldehyde compound is slowly added to react. The reaction of step (2') can be carried out in the presence of an acidic catalyst, for example, p-toluenesulfonic acid. The amount of the acidic catalyst can be 0.2 mol%-1 mol% of the amount of the phenolic compound. The reaction temperature can be 120-180°C, for example, 150°C, and the reaction time can be 1 h-12 h, for example, 2 h, 3 h, 4 h, or 6 h. After the reaction of step (2') is completed, water and free phenolic compounds can be removed by distillation under reduced pressure, and then a base can be added to quench the reaction.

[0082] like Figure 1 As shown in (b), in some embodiments, the ionic liquid-modified phenolic resin of the present invention as a reinforcing resin is synthesized by the following method: phenol and an acidic catalyst are melted, and formaldehyde is added dropwise for polycondensation; a modifier (tall oil and / or cashew oil) is then added, and an olefinic ionic liquid is added for reaction; water and free phenol are removed by distillation under reduced pressure; and a base is added for neutralization, quenching the reaction and discharging.

[0083] In some embodiments, the ionic liquid-modified phenolic resin used as a tackifying resin of the present invention is synthesized by the following method: alkylphenol, optionally added phenol and an acidic catalyst are melted, and an aldehyde compound is added dropwise for polycondensation; an alkenyl ionic liquid is then added for reaction; water and free phenol are removed by vacuum distillation; and finally, the mixture is neutralized and discharged.

[0084] The present invention has the following beneficial effects: the present invention adopts ionic liquid to modify phenolic resin, which is applied to the rubber composition, thereby enhancing the interaction between the resin and the filler. While maintaining the viscosity-increasing or reinforcing effect of the resin itself, the adsorption of the filler on the vulcanization system can be reduced, thereby improving the mechanical properties of the rubber compound, shortening the positive vulcanization time, and improving the vulcanization performance of the rubber compound.

[0085] The ionic liquid-modified phenolic resin of the present invention can be used as a tackifying resin or a reinforcing resin in rubber, and while improving the surface viscosity of the rubber, it can also reduce the compression fatigue heat generation of the rubber. Therefore, the present invention also includes a rubber composition comprising the ionic liquid-modified phenolic resin of the present invention. The rubber composition of the present invention can be a tire rubber composition.

[0086] The raw material of rubber composition generally includes diene elastomer, reinforcing filler, antioxidant and cross-linking agent.The raw material of rubber composition of the present invention also includes the ionic liquid modified phenolic resin of the present invention as tackifying resin or reinforcing resin.Herein, rubber composition includes unvulcanized rubber and vulcanized rubber.Unvulcanized rubber can make vulcanized rubber through vulcanization (curing).

[0087] In the raw materials of the rubber composition of the present invention, based on 100 parts by weight of the diene elastomer, the reinforcing filler content may be 30-80 parts by weight, the antioxidant content may be 0.1-8 parts by weight, the crosslinking agent content may be 0.5-10 parts by weight, and the ionic liquid-modified phenolic resin of the present invention, which serves as a tackifying resin or reinforcing resin, may be present in an amount of 1-20 parts by weight, for example, 10±1 parts by weight. Unless otherwise specified herein, parts by weight are calculated relative to 100 parts by weight of the diene elastomer contained in the raw materials of the rubber composition.

[0088] As used herein, a diene elastomer refers to an elastomer whose monomers contain a diene (e.g., butadiene, isoprene). Suitable diene elastomers for use in the present invention may be various diene elastomers known in the art, including but not limited to one or more selected from natural rubber (NR), butadiene rubber (BR), isoprene rubber, styrene-butadiene rubber (SBR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), isoprene / butadiene copolymers, isoprene / styrene copolymers, and isoprene / butadiene / styrene copolymers. In some embodiments, the diene elastomer in the raw materials of the rubber composition of the present invention is natural rubber.

[0089] The antioxidant applicable to the present invention can be various antioxidants commonly used in rubber compositions, such as antioxidant 6PPD. The raw materials of the rubber composition of the present invention generally include 0.1-8 parts by weight, preferably 1-5 parts by weight, and more preferably 3.5±0.5 parts by weight of the antioxidant.

[0090] Reinforcing filler applicable to the present invention can be the reinforcing filler conventionally used for rubber composition, includes but not limited to be selected from one or more in carbon black, white carbon black, titanium oxide, magnesium oxide, calcium carbonate, magnesium carbonate, aluminium hydroxide, magnesium hydroxide, clay and talc.The raw material of rubber composition generally comprises 30-80 weight parts, preferably 40-70 mass parts of reinforcing filler.In some embodiments, in rubber composition of the present invention, reinforcing filler is carbon black.

[0091] The crosslinking agent may be sulfur. The raw materials of the rubber composition generally contain 0.5-10 parts by weight, preferably 1-6 parts by weight, for example 4±1 parts by weight of the crosslinking agent. In some embodiments, in the rubber composition of the present invention, the crosslinking agent is insoluble sulfur.

[0092] The raw materials of the rubber composition of the present invention may also include other ingredients commonly used in rubber compositions, including but not limited to one or more of an activating agent, an accelerator, and a softener. The respective amounts of the activating agent, the accelerator, and the softener may be conventional amounts in the art.

[0093] The activating agent can accelerate the vulcanization rate, improve the thermal conductivity, wear resistance, and tear resistance of the rubber. The activating agent can be zinc oxide. In some embodiments, the raw materials of the rubber composition of the present invention include an activating agent, such as zinc oxide. The raw materials of the rubber composition of the present invention can include 0-10 parts by weight, preferably 2-10 parts by weight, for example 5±1 parts by weight of an activating agent, such as zinc oxide.

[0094] Accelerator is generally a vulcanization accelerator, and can be selected from one or more of sulfonamide vulcanization accelerator, thiazole vulcanization accelerator, thiuram vulcanization accelerator, thiourea vulcanization accelerator, guanidine vulcanization accelerator, dithiocarbamate vulcanization accelerator, aldehyde amine vulcanization accelerator, aldehyde ammonia vulcanization accelerator, imidazoline vulcanization accelerator and xanthate vulcanization accelerator.For example, accelerator can be accelerator NS (N- tert-butyl -2- benzothiazole sulfenamide) and accelerator HMT (hexamethylenetetramine).The raw material of rubber composition of the present invention can include 0-5 weight portion, preferably 3-4 weight portion accelerator.In some embodiments, accelerator includes accelerator NS and accelerator HMT, and the mass ratio of the two can be 1:2 to 2:1, for example 1:1.

[0095] The effect of softening agent is mainly to improve the performances such as processability.Softening agent can comprise petroleum-based softening agent, such as naphthenic oil, aromatic oil, process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt and vaseline etc., can also comprise fatty oil softening agent, such as stearic acid, castor oil, linseed oil, rapeseed oil, coconut oil, wax (such as beeswax, carnauba wax and lanolin), tall oil, linoleic acid, palmitic acid and lauric acid etc.In some embodiments, the raw material of rubber combination of the present invention comprises petroleum-based softening agent (such as naphthenic oil) and fatty oil softening agent (such as stearic acid).The raw material of rubber combination of the present invention can comprise 0-20 weight portion, preferably 1-10 weight portion, more preferably 2-8 weight portion, the process oil of for example 6 ± 1 weight portions, for example naphthenic oil. The raw materials of the rubber composition of the present invention may contain 0-5 parts by weight, preferably 0.5-4 parts by weight, more preferably 1-3 parts by weight, for example 2±0.5 parts by weight, 2±0.2 parts by weight of a fatty oil softener, such as stearic acid.

[0096] In some embodiments, the raw materials of the rubber composition of the present invention include or consist of the following components: a diene elastomer, a tackifying resin (or reinforcing resin), a crosslinking agent, a reinforcing filler, an active agent, a softener, an antioxidant, a rubber binder, and an accelerator.

[0097] The unvulcanized rubber of the present invention can be prepared by a conventional rubber mixing method, for example, a two-stage mixing method: a first stage of mixing in an internal mixer, mixing other raw materials except the crosslinking agent and the accelerator to obtain a masterbatch, and the discharge temperature can be 150±10°C; a second stage of mixing in an open mixer, mixing the masterbatch obtained in the first stage, the crosslinking agent and the accelerator to obtain the unvulcanized rubber.

[0098] The unvulcanized rubber of the present invention can be vulcanized using conventional vulcanization methods to obtain vulcanized rubber. The vulcanization temperature is typically 130°C to 200°C, for example, 150±2°C. The vulcanization time depends on the vulcanization temperature, the vulcanization system, and the vulcanization kinetics, and is typically 15-60 minutes, for example, 40±5 minutes. Prior to vulcanization, the unvulcanized rubber obtained by mixing can be subjected to conventional sheeting.

[0099] The present invention also provides a rubber product, wherein part or all of the rubber product is made from, or is prepared from, the rubber composition described in any embodiment of the present invention. The rubber product may include tires, rubber shoes, sealing strips, sound insulation panels, vibration damping pads, and the like.

[0100] The present invention will be described below by way of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents, and materials used in the examples are, unless otherwise stated, conventional methods, reagents, and materials in the art. The starting compounds in the examples can all be purchased from commercial sources.

[0101] In the present invention, high performance liquid chromatography is adopted to determine the contents of free phenol and free alkylphenol.

[0102] In the present invention, the softening point of the prepared resin is measured according to GB / T 4507.

[0103] Example 1

[0104] To a 250ml round-bottom four-necked flask equipped with a mechanical stirrer, a thermometer, and a reflux condenser, 1.0mol of phenol, 0.005mol of p-toluenesulfonic acid, and 0.05mol of 1-allyl-3-methylimidazolium chloride were added and reacted at 100°C for 1 hour for modification. 0.66mol of formaldehyde was then added dropwise for polycondensation, and the mixture was refluxed at 100°C for another hour. After the reflux, 23.5g (0.078mol) of cashew nut oil was added to continue the modification. The mixture was heated to 150°C and distilled at atmospheric pressure for 4h to remove a large amount of water. After that, the mixture was distilled under reduced pressure for 2h to remove residual moisture. The mixture was then neutralized with 0.005mol of triethanolamine to obtain 102.4g of modified phenolic resin. The softening point of the prepared modified phenolic resin was 71.4°C, and no free phenol was detected. The product was designated as resin A1 and can be used as a reinforcing resin.

[0105] Example 2

[0106] In a 250ml round-bottomed four-necked flask equipped with a mechanical stirrer, a thermometer, and a reflux condenser, 1.0 mol of phenol and 0.005 mol of p-toluenesulfonic acid were added, and 0.66 mol of formaldehyde was added dropwise at 100 ° C for polycondensation. After refluxing at 100 ° C for 1 hour, 0.05 mol of 1-allyl-3-methylimidazolium chloride and 23.5 g (0.078 mol) of cashew nut oil were added for modification. The mixture was heated to 150 ° C and distilled at atmospheric pressure for 4 hours to remove a large amount of water. After that, the mixture was distilled under reduced pressure for 2 hours to remove residual moisture. After neutralization with 0.005 mol of triethanolamine, 108.3 g of modified phenolic resin was obtained. The softening point of the prepared modified phenolic resin was 72.7 ° C and the free phenol content was 0.12%. The product was recorded as resin A2 and can be used as a reinforcing resin.

[0107] Example 3

[0108] In a 250ml round-bottomed four-necked flask equipped with a mechanical stirrer, a thermometer, and a reflux condenser, 1.0 mol of phenol, 0.005 mol of p-toluenesulfonic acid, and 0.05 mol of 1-allyl-3-methylimidazolium chloride were added and prepolymerized at 100°C for 1 hour. 0.75 mol of formaldehyde was then added dropwise for prepolymerization, and refluxed at 100°C for 1 hour. After reflux, 23.5 g (0.078 mol) of cashew nut oil was added to continue modification. The mixture was heated to 0.150°C and distilled at atmospheric pressure for 4 hours to remove a large amount of water. After that, the mixture was distilled under reduced pressure for 2 hours to remove residual moisture. The mixture was quenched with 0.005 mol of triethanolamine to obtain 104.5 g of modified phenolic resin. The softening point of the prepared modified phenolic resin was 76.4°C, and the free phenol content was 0.01%. The product was designated as resin A3 and can be used as a reinforcing resin.

[0109] Example 4

[0110] In a 250ml round-bottomed four-necked flask equipped with a mechanical stirrer, a thermometer, and a reflux condenser, 1.0mol of phenol, 0.005mol of p-toluenesulfonic acid, and 0.01mol of 1-allyl-3-methylimidazolium chloride were added and reacted at 100°C for 1 hour. 0.75mol of formaldehyde was then added dropwise for polycondensation, and refluxed at 100°C for 1 hour. 23.5g (0.078mol) of cashew nut oil was then added to continue modification. The mixture was heated to 150°C and distilled at atmospheric pressure for 4h to remove a large amount of water. After that, the mixture was distilled under reduced pressure for 2h to remove residual moisture. The mixture was quenched with 0.005mol of triethanolamine to obtain 106.6g of modified phenolic resin. The softening point of the prepared modified phenolic resin was 87.0°C, and the free phenol content was 0.71%. The product was designated as resin A4 and can be used as a reinforcing resin.

[0111] Example 5

[0112] To a 250ml round-bottom four-necked flask equipped with a mechanical stirrer, thermometer, and reflux condenser, 1.0 mol of phenol, 0.005 mol of p-toluenesulfonic acid, and 0.05 mol of 1-allyl-3-methylimidazolium chloride were added and reacted at 100°C for 1 hour. 0.65 mol of formaldehyde was then added dropwise for a polycondensation reaction, and the mixture was refluxed at 100°C for 1 hour. 38g (0.134 mol) of tall oil was then added to continue the modification. The mixture was heated to 150°C and distilled at atmospheric pressure for 3 hours to remove the bulk of the water. The mixture was quenched with 0.005 mol of triethanolamine and then distilled under reduced pressure for 2 hours to remove trace amounts of water, yielding 111.8g of a modified phenolic resin. The resulting modified phenolic resin had a softening point of 79.4°C and a free phenol content of 0.58%. This product, designated Resin A5, can be used as a reinforcing resin.

[0113] Example 6

[0114] To a 250ml round-bottom four-necked flask equipped with a mechanical stirrer, thermometer, and reflux condenser, 1.0 mol of phenol, 0.005 mol of p-toluenesulfonic acid, and 0.01 mol of 1-allyl-3-methylimidazolium chloride were added and reacted at 100°C for 50 minutes. 0.70 mol of formaldehyde was added dropwise for polycondensation, and the mixture was refluxed at 100°C for 1 hour. 38g (0.134 mol) of tall oil was then added to continue the modification. The mixture was heated to 150°C and distilled at atmospheric pressure for 3 hours to remove the bulk of the water. The mixture was quenched with 0.005 mol of triethanolamine and then distilled under reduced pressure for 2 hours to remove trace amounts of water, yielding 113.2g of a modified phenolic resin. The resulting modified phenolic resin had a softening point of 91.7°C and a free phenol content of 0.02%. This product, designated Resin A6, can be used as a reinforcing resin.

[0115] Example 7

[0116] To a 250ml round-bottomed four-necked flask equipped with a mechanical stirrer, a thermometer, and a reflux condenser, 0.9mol of p-tert-octylphenol, 0.1mol of phenol, and 0.005mol of p-toluenesulfonic acid were added, and 0.8mol of formaldehyde was added dropwise. After refluxing at 100°C for 1 hour, 0.05mol of 1-allyl-3-methylimidazole chloride was added. The mixture was heated to 150°C and atmospherically distilled for 3h to remove a large amount of water, and the mixture was neutralized with 0.005mol of triethanolamine. Trace amounts of water and unreacted free p-tert-octylphenol were subsequently removed by underpressure distillation for 2h to obtain a modified tert-octyl tackifying resin (yield 96%). The prepared modified tert-octyl tackifying resin had a softening point of 89.1°C and a free alkylphenol content of 4.84%. This product, designated Resin A7, can be used as a tackifying resin.

[0117] Example 8

[0118] In a 250ml round-bottomed four-necked flask equipped with a mechanical stirrer, a thermometer, and a reflux condenser, 0.9mol p-tert-butylphenol, 0.1mol phenol, and 0.005mol tosic acid were added, and 0.8mol formaldehyde was added dropwise. After refluxing at 100°C for 1 hour, 0.05mol 1-allyl-3-methylimidazole chloride was added. The mixture was then heated to 150°C and distilled under reduced pressure for 3h to remove a large amount of water, and the mixture was neutralized with 0.005mol triethanolamine. Afterwards, trace water and unreacted free p-tert-butylphenol were removed by underpressure distillation for 2h to obtain a modified tert-butyl tackifying resin (yield 93%). The softening point of the prepared modified tert-butyl tackifying resin was 121.3°C, and the free alkylphenol content was 0.63%. This product is designated as Resin A8 and can be used as a tackifying resin.

[0119] Comparative Example 1

[0120] To a 250ml round-bottom four-necked flask equipped with a mechanical stirrer, a thermometer, and a reflux condenser, 1.0mol of phenol and 0.005mol of p-toluenesulfonic acid were added, and 0.65mol of formaldehyde was added dropwise for polycondensation, and refluxed at 100°C for 1 hour. Then 23.5g (0.078mol) of cashew nut oil was added for modification. The temperature was raised to 150°C and distilled at normal pressure for 4h to remove a large amount of water, and then the residual water was removed by reduced pressure distillation for 2h. Finally, 0.005mol of triethanolamine was used for neutralization reaction to obtain 103.9g of modified phenolic resin. The softening point of the prepared modified phenolic resin was 82.3°C, and no free phenol was detected. The product was recorded as resin B1 and can be used as a reinforcing resin.

[0121] Comparative Example 2

[0122] To a 250ml round-bottom four-necked flask equipped with a mechanical stirrer, thermometer, and reflux condenser, 1.5 mol of phenol and 0.008 mol of p-toluenesulfonic acid were added. 0.975 mol of formaldehyde was then added dropwise for polycondensation. The mixture was refluxed at 100°C for 1 hour. 38g (0.134 mol) of tall oil was then added for modification. The mixture was heated to 150°C and distilled at atmospheric pressure for 3 hours to remove the bulk of the water. The reaction was neutralized with 0.005 mol of triethanolamine and distilled at reduced pressure for 2 hours to remove trace amounts of water. 164.8g of modified phenolic resin was obtained. The softening point of the prepared modified phenolic resin was 85.0°C, and no free phenol was detected. This product, designated Resin B2, can be used as a reinforcing resin.

[0123] Comparative Example 3

[0124] To a 250ml round-bottom four-necked flask equipped with a mechanical stirrer, thermometer, and reflux condenser, add 0.46 mol of p-tert-octylphenol and 0.0023 mol of p-toluenesulfonic acid. Heat and melt. Then, add 0.39 mol of formaldehyde dropwise for a polycondensation reaction. Retain at 100°C for 1 hour. Then, heat to 150°C and distill under atmospheric pressure for 3 hours to remove the bulk of the water. Neutralize with 0.0023 mol of triethanolamine, and distill under reduced pressure for 2 hours to remove trace amounts of water. This yields a modified alkylphenol-formaldehyde resin (yield 98%). The resulting modified alkylphenol-formaldehyde resin has a softening point of 90.7°C and a free alkylphenol content of 4.85%. It is designated B3 and can be used as a tackifying resin.

[0125] Application Examples

[0126] In order to investigate the effect of ionic liquid modified resin on improving the mechanical properties of rubber products and to investigate whether the modification of the resin affects the processing properties of the rubber, a rubber composition was prepared according to the following rubber compound formulation and rubber mixing process.

[0127] Compound formula:

[0128] 100 parts by weight of natural rubber; 10 parts by weight of reinforcing resin; 70 parts by weight of carbon black; 5.0 parts by weight of zinc oxide; 2.0 parts by weight of stearic acid; 3.5 parts by weight of antioxidant 6PPD; 6.0 parts by weight of naphthenic oil; 4.0 parts by weight of insoluble sulfur; 1.7 parts by weight of accelerator NS; and 1.7 parts by weight of accelerator HMT. Resins A4, B1, A6, and B2 are used as reinforcing resins in rubber compositions 1-4, respectively.

[0129] Rubber mixing process:

[0130] Raw rubber, zinc oxide, reinforcing resin, antioxidant, stearic acid, naphthenic oil, and carbon black were mixed in an internal mixer at a discharge temperature of 150°C. A second mixing stage was performed on an open mixer, where accelerator and insoluble sulfur were added, followed by thinning and rolling. After cooling and allowing the rubber to rest for a period of time, it was vulcanized on a flat-plate vulcanizer at 151°C for 40 minutes.

[0131] Test Case

[0132] The properties of the rubber composition were tested according to the following performance test methods, and the structures are shown in Tables 1 and 2:

[0133] Mooney and vulcanization properties are measured in accordance with GB / T 16584-1996 and GB / T 1233-2008;

[0134] Physical properties are tested according to GB / T 528-2009 standard;

[0135] Thermal oxidative aging test is carried out according to GB / T 3512-2014;

[0136] The dynamic performance experiment is carried out according to GB / T 9870.1-2006.

[0137] Table 1: Properties of Rubber Composition 1 and Rubber Composition 2

[0138]

[0139]

[0140] As can be seen from Table 1, the rubber compound (rubber composition 1) prepared using the ionic liquid-modified cashew nut oil-reinforced resin A4 of Example 4 has a decreased vulcanization time and increased mechanical properties, while the other properties remain basically unchanged, compared to the rubber compound (rubber composition 2) prepared using the unmodified cashew nut oil-reinforced resin B1 of Comparative Example 1.

[0141] Table 2: Properties of Rubber Composition 3 and Rubber Composition 4

[0142]

[0143]

[0144] As can be seen from Table 2, the rubber compound prepared using the ionic liquid-modified tall oil reinforcing resin A6 of Example 6 (rubber composition 3) has a shorter cure time and improved mechanical properties, while the other properties remain basically unchanged, compared to the rubber compound prepared using the unmodified tall oil reinforcing resin B2 of Comparative Example 2 (rubber composition 4).

[0145] Based on the above experimental results, it can be seen that the present invention can improve the application effect of phenolic resin as a rubber additive by using ionic liquid as a modifier for phenolic resin, that is, shorten the curing time and improve the mechanical properties.

Claims

1. An ionic liquid modified phenolic resin, characterized in that: The ionic liquid modified phenolic resin is formed by reacting a phenolic compound, an ionic liquid, an aldehyde compound and an optional modifier; The phenolic compound has a structure shown in Formula I: In formula I, R1 is selected from H and C1-C20 alkyl; The ionic liquid is a compound of formula II: The modifier is selected from one or both of cashew nut oil and tall oil.

2. The ionic liquid modified phenolic resin according to claim 1, characterized in that In formula I, R1 is selected from H and C1-C10 alkyl; preferably, R1 is selected from H, tert-octyl and tert-butyl; and / or The aldehyde compound is selected from one or more of formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, hexanal, benzaldehyde and furfural, preferably formaldehyde.

3. The ionic liquid modified phenolic resin according to claim 1, characterized in that In the raw materials of the ionic liquid modified phenolic resin, the molar ratio of the phenolic compound to the ionic liquid is 1:(0.01-0.1), and / or the molar ratio of the phenolic compound to the aldehyde compound is 1:(0.6-0.9), and / or the molar ratio of the phenolic compound to the modifier is 1:(0-0.2); Preferably, the raw material of the ionic liquid modified phenolic resin does not include a modifier, and the molar ratio of the phenolic compound, the ionic liquid and the aldehyde compound in the raw material of the ionic liquid modified phenolic resin is 1: (0.01-0.05): (0.65-0.8); Preferably, the raw material of the ionic liquid modified phenolic resin includes a modifier, and the molar ratio of the phenolic compound, the ionic liquid, the aldehyde compound and the modifier in the raw material of the ionic liquid modified phenolic resin is 1: (0.01-0.05): (0.65-0.8): (0.05-0.15).

4. The ionic liquid modified phenolic resin according to claim 1, characterized in that The ionic liquid modified phenolic resin is formed by reacting a phenolic compound, an ionic liquid, an aldehyde compound and a modifier, and the phenolic compound is phenol; or The ionic liquid modified phenolic resin is formed by the reaction of a phenolic compound, an ionic liquid and an aldehyde compound, and the phenolic compound comprises a compound of formula IA and optionally phenol: In formula IA, R2 is selected from C1-C20 alkyl, preferably tert-octyl and tert-butyl; preferably, the mass fraction of phenol in the phenolic compound is 0 to 20%.

5. A method for preparing the ionic liquid modified phenolic resin according to any one of claims 1 to 4, characterized in that: The method comprises: (1) subjecting the phenolic compound to a Friedel-Crafts reaction with the ionic liquid to obtain a compound of formula III, wherein R1 is selected from H and C1-C20 alkyl: (2) subjecting the phenolic compound, the compound of formula III and the aldehyde compound to a condensation polymerization reaction, and optionally adding a modifier to the reaction system for reaction to obtain the ionic liquid modified phenolic resin.

6. The method according to claim 5, characterized in that The method has one or more of the following features: The reaction of step (1) and step (2) is carried out in the presence of an acidic catalyst; the acidic catalyst is preferably selected from one or more of p-toluenesulfonic acid, methanesulfonic acid, benzenesulfonic acid, benzene disulfonic acid, dodecylbenzenesulfonic acid, hydrochloric acid, sulfuric acid and phosphoric acid, more preferably p-toluenesulfonic acid; the amount of the acidic catalyst is preferably 0.2 mol% to 1 mol% of the amount of the phenolic compound; The reaction temperature of step (1) is 50-180° C., and the reaction time is 10 min-5 h; The polycondensation reaction temperature in step (2) is 100-140° C., and the polycondensation reaction time is 10 min-12 h. After adding the modifier, the reaction temperature is 120-180° C. and the reaction time is 1 h-12 h.

7. A method for preparing the ionic liquid modified phenolic resin according to any one of claims 1 to 4, characterized in that: The method comprises: (1') subjecting the phenolic compound to a condensation polymerization reaction with an aldehyde compound to obtain a phenolic resin; (2') reacting the phenolic resin with the ionic liquid and an optionally added modifier to obtain the ionic liquid-modified phenolic resin.

8. The method according to claim 7, characterized in that The method has one or more of the following features: The reaction of step (1') and step (2') is carried out in the presence of an acidic catalyst; the acidic catalyst is preferably selected from one or more of p-toluenesulfonic acid, methanesulfonic acid, benzenesulfonic acid, benzene disulfonic acid, dodecylbenzenesulfonic acid, hydrochloric acid, sulfuric acid and phosphoric acid, more preferably p-toluenesulfonic acid; the amount of the acidic catalyst is preferably 0.2 mol% to 1 mol% of the amount of the phenolic compound; The reaction temperature of step (1') is 100-140°C, and the reaction time is 10min-12h; The reaction temperature of step (2') is 120-180°C, and the reaction time is 1h-12h.

9. A rubber composition, characterized in that: The rubber composition contains a diene elastomer and the ionic liquid-modified phenolic resin according to any one of claims 1 to 4; preferably, in the rubber composition, the mass ratio of the diene elastomer to the ionic liquid-modified phenolic resin is 100:(1 to 20).

10. Use of the ionic liquid modified phenolic resin according to any one of claims 1 to 4 in improving the vulcanization properties and / or mechanical properties of rubber.

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