Mulcitraconomide oligomer, preparation method, composition and application of mulcitraconomide oligomer

Abstract

The invention relates to the technical field of rubber additives, in particular to a citraconomide oligomer, a preparation method, a composition and application thereof. The structural general formula of the doraconomide oligomer is shown in the specification, wherein R1 and R2 are selected from one of hydrogen atoms, halogen atoms, nitryl, C1-C20 aliphatic groups or derivatives thereof, and C6-C12 aromatic hydrocarbon alkyl groups or derivatives thereof; and n is an integer of 0-30. According to the invention, the prepared citraconomide oligomer is used as a rubber additive and is added into diene rubber and filler components, polyfunctional groups of the citraconomide oligomer activate the filler and the rubber surface, a rubber network is enhanced, and the rubber composition is endowed with excellent tear resistance, high modulus, high hardness, anti-reversion performance and low hysteresis loss.

Description

Technical Field

[0001] This invention relates to the field of rubber additives technology, and in particular to a polyciconimide oligomer, its preparation method, its composition, and its application. Background Technology

[0002] With the accelerating trend towards greener automotive manufacturing, the demand for low fuel consumption and long tire life has become a core challenge for the industry. Low fuel consumption requires a significant reduction in rolling resistance (reduced hysteresis loss), which hinges on suppressing dynamic heat generation. Long tire life demands high tear strength, high modulus, and excellent aging resistance. During rubber vulcanization, reversion is a key bottleneck restricting the durability of high-performance products. When over-vulcanization occurs, polysulfide crosslinks (-S...)... x -) The breakage and rearrangement into unstable short sulfur bonds (-S1- / S2-) leads to a significant decrease in crosslinking density, resulting in performance degradation, such as decreased hardness, large hysteresis loss, and worse wear, ultimately leading to a reduction in lifespan.

[0003] Chinese invention patent CN109265908A provides an improved rubber reversion resistant agent. Although its precise component ratio stabilizes the performance of the rubber reversion resistant agent and improves tear resistance and flowability, additional additives may be needed to meet higher requirements in certain applications (such as those requiring extreme aging resistance or oil resistance), and its applicability is limited. Furthermore, while the dual-layer tread design (low-heat-generating surface rubber + high-load-bearing base rubber) balances performance, it increases the risk of interfacial delamination. Traditional modulus enhancers (such as phenolic resins) improve hardness but shorten dynamic fatigue life. Using traditional reversion resistant agents: the rigid cross-linked network of bismaleimide leads to stress concentration and accelerates fatigue crack propagation; 1,3-bis(citronimide methyl)benzene and other reversion resistant agents are prone to sticking to rollers due to their molecular rigidity, and uneven dispersion causes localized performance degradation.

[0004] Therefore, there is an urgent need for a solution that can reduce heat generation, increase modulus, and achieve high tear strength, while also being compatible with the rubber matrix to avoid sticking to rollers and dispersion defects; and achieving long-lasting durability by resisting thermo-oxidative aging and inhibiting dynamic performance degradation. Summary of the Invention

[0005] To address the aforementioned technical problems, the first aspect of the present invention provides a polyciconimide oligomer, the general structural formula of which is:

[0006] R1 and R2 are both selected from hydrogen atoms, halogen atoms, nitro groups, and C1-C atoms. 20 aliphatic groups or their derivatives, C6-C 12 One of the aromatic hydrocarbon alkyl groups or their derivatives; n is an integer from 0 to 30.

[0007] In one embodiment, the repeating unit structures represented by n in the general formula of the polyciconimidin oligomer are the same or different, and when the repeating unit structures are different, it includes 2-8 repeating unit structures.

[0008] When n = 0, the structure is as follows:

[0009] When n=1, the structure is:

[0010] A second aspect of the present invention provides a method for preparing polycitrinimide oligomers, comprising at least:

[0011] S1, citrile anhydride reacts with polyamines to produce polycitralic acid;

[0012] S2. The polycitamide acid is dehydrated and cyclized under the action of a catalyst to generate polycitamide oligomer.

[0013] In one embodiment, step S1 specifically involves: dissolving citral anhydride in a solvent, slowly adding a polyamine dissolved in the same solvent, and then heating the mixture to react, thereby obtaining a polycitralamic acid reaction solution.

[0014] In one embodiment, the temperature conditions for the reaction in step S1 are 40-60°C and the reaction time is 1-2 hours.

[0015] In one embodiment, step S2 specifically involves: adding a catalyst to the polycitralamide reaction solution, heating for dehydration and cyclization reaction, cooling to room temperature, pouring the reaction solution into water for filtration and retaining the filter cake, and then washing and drying to obtain the polycitralimide oligomer.

[0016] In one embodiment, the dehydration cyclization reaction in step S2 is carried out under reflux for 1-5 hours. More preferably, it is 2-4 hours.

[0017] In one embodiment, the molar ratio of the citrine anhydride to the amino groups in the polyamine is (1-1.2):1.

[0018] In one embodiment, the molar ratio of the catalyst to the amino groups in the polyamine is (0.01-0.8):1.

[0019] In one embodiment, the mass ratio of the solvent to citrine anhydride in step S1 is (3-20):1.

[0020] In one embodiment, the solvent includes one or more of benzene, toluene, xylene, cyclohexane, n-hexane, diethyl ether, diisopropyl ether, ethyl acetate, butyl acetate, methyl isobutyl ketone, cyclopentanone, dichloromethane, chloroform, dichloroethane, dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinedione, and N-methyl-2-pyrrolidone.

[0021] In one embodiment, the catalyst comprises at least one selected from acetic acid, sulfuric acid, phosphoric acid, p-toluenesulfonic acid, methanesulfonic acid, benzenesulfonic acid, p-chlorobenzenesulfonic acid, p-nitrobenzenesulfonate acid, formic acid, zinc chloride, ferric chloride, and aluminum chloride.

[0022] A third aspect of the present invention provides a rubber composition, wherein the raw materials for preparation include the polycitrinimide oligomer.

[0023] In one embodiment, the raw materials for preparing the rubber composition include: 100 parts of diene rubber, 10-120 parts of filler, 0.01-30 parts of rubber additive, 1-10 parts of sulfur, 0.5-2 parts of accelerator, 1-5 parts of stearic acid, 1-6 parts of zinc oxide, 1-5 parts of antioxidant, and 1-5 parts of protective wax, wherein the rubber additive is a polycitrinimide oligomer.

[0024] In a preferred embodiment, the raw materials for preparing the rubber composition include: 100 parts of diene rubber, 20-80 parts of filler, 0.2-10 parts of rubber additive, 1-4 parts of sulfur, 1-2 parts of accelerator, 1-5 parts of stearic acid, 3-5 parts of zinc oxide, 1-4 parts of antioxidant and 1-2 parts of protective wax, wherein the rubber additive is a polycitrinimide oligomer.

[0025] In one embodiment, the diene-based rubber includes at least one of natural rubber and diene-based synthetic rubber.

[0026] In one embodiment, the diene-based synthetic rubber includes at least one of styrene-butadiene copolymer, cis-butadiene rubber, isoprene rubber, butadiene-isopropylene copolymer, butadiene-styrene-isopropylene copolymer, acrylonitrile-butadiene copolymer, and butyl rubber.

[0027] In one embodiment, the filler includes at least one of carbon black and silica.

[0028] In one embodiment, the specific surface area of ​​the carbon black is 30-200 m². 2 / g. The carbon black grade includes at least one of N110, N121, N134, N220, N231, N234, N242, N293, N299, N315, N326, N330, N332, N339, N343, N347, N351, N358, N375, N539, N550, N582, N630, N642, N650, N683, N754, N762, N765, N774, N787, and N990.

[0029] In one embodiment, the specific surface area of ​​the silica is 60-250 m². 2 / g. The carbon black grade includes at least one of 115MP, 115G, 165MP, 165G, 175G, 175MP, 200MP, and 200G.

[0030] In one embodiment, the accelerator is a sulfenamide accelerator, which includes one or more of accelerators CZ, CBS, and NS.

[0031] In one embodiment, the sulfur is insoluble sulfur.

[0032] Another aspect of the present invention provides a method for preparing the rubber composition, comprising: plasticizing diene rubber for 30 seconds at a rotation speed of 50-80 r / min, then adding filler and polycitrinimide oligomer and mixing for 100-180 seconds at a temperature of 150°C, then adding stearic acid, zinc oxide, antioxidant, and protective wax and mixing at a temperature of 155°C for 120 seconds, then feeding the mixed rubber into a two-roll mill, mixing it evenly, then adding sulfur and accelerator, dispersing it evenly, forming five triangular wraps, then adjusting the roller gap to 3 mm, and finally sheeting the rubber compound to obtain the rubber composition.

[0033] A fourth aspect of the present invention provides an application of a rubber composition used in the manufacture of tire components, shock-absorbing components, and seals. The tire components include areas requiring reinforcement and toughening, such as tread rubber, base rubber, gusset rubber, bead, shoulder rubber, sidewall rubber, airtight layer, and skeleton adhesive layer.

[0034] Beneficial effects:

[0035] 1. This invention provides a method for preparing polycitrinimide oligomers with high yield and low cost. The polycitrinimide oligomers improve modulus and hardness through the design of rigid imide rings, and the flexible oligomer segments improve flowability, which is beneficial for dispersion and improved processing performance. The multifunctional surface-activated filler-rubber interface coupling and rubber elastomer strengthen the molecular chain network; inhibiting the movement of free molecular chain segments reduces internal hysteresis loss and limits crack growth, thereby reducing heat generation while improving tear strength.

[0036] 2. In this invention, the prepared polyciconimide oligomer is used as a rubber additive and added to diene rubber and filler components. Its multifunctional groups activate the filler and rubber surface, enhance the rubber network, and endow the rubber composition with excellent tear resistance, high modulus, high hardness, anti-reversion properties and low hysteresis loss.

[0037] 3. The present invention uses the prepared polycitrinimide oligomer as a rubber additive. It can be added during the initial mixing of diene rubber and filler components, or it can be added in the final stage with the vulcanization accelerator system. Experiments have shown that when added in the final stage, it can be uniformly dispersed in the rubber composition without sticking to the roller.

[0038] 4. The preparation method of polyciconimide oligomers provided by the present invention is simple. It is synthesized through a two-step process, and the yield of polyciconimide oligomers obtained is greater than 90%, which enriches the structural diversity of ciconimide rubber additives. Attached Figure Description

[0039] Figure 1 This is a process flow diagram of this application;

[0040] Figure 2 The infrared spectrum of polycitric acid obtained in step S1 of Example 1;

[0041] Figure 3 The infrared spectrum of the polyciconimidin oligomer obtained in Example 1;

[0042] Figure 4 The hydrogen spectrum of the polyciconimidin oligomer obtained in Example 1 is shown. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Experimental methods not specifying specific conditions in the embodiments were performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0044] The rubber in question is a diene rubber, No. 3 smoked sheet rubber, purchased from Vietnam.

[0045] The antioxidant was purchased from Sunon Chemical Technology Co., Ltd., and its model number is 6PPD.

[0046] The protective wax is from Jiangsu Ruiba New Material Technology Co., Ltd., and its model number is HW287.

[0047] The phenolic reinforcing resin is from Shandong Ruiba New Material Technology Co., Ltd., and its model number is RN2670.

[0048] Example 1

[0049] The first aspect of this example provides a polyciconimidin oligomer, the general structural formula of which is:

[0050] Where n is 0, 1, 2, or 3.

[0051] The second aspect of this example provides a method for preparing polyciconimidin oligomers, including:

[0052] S1. In a 2000ml four-necked flask equipped with a condenser, thermometer, and stirrer, 125.8g of citral anhydride (1.12mol) was dissolved in 100g of toluene and stirred. At room temperature, 100g of polyphenyl polyaminomethane (a mixture of n=0-3) (1.02mol) was dissolved in 500g of toluene and added slowly dropwise at room temperature. A yellow precipitate formed during the dropwise addition, and the addition time was 1.5h. After the dropwise addition was completed, the temperature was raised to 60℃ and the reaction was allowed to proceed for 1h. A yellow paste-like reaction solution was obtained, in which the yellow solid was citralamide acid.

[0053] S2. Add 25g of catalyst to the yellow paste-like reaction solution, heat to 120℃, reflux to remove water for 5h. After the reaction is complete, cool to room temperature, pour the reaction solution into water to obtain an orange-yellow precipitate, filter and retain the orange-yellow filter cake, wash the filter cake with water until neutral, and vacuum dry to obtain the orange-yellow product polycitidine oligomer (185.3g), with a product yield of 96.5%. Softening point 83.5℃, acid value 0.80mgKOH / g.

[0054] The catalyst is p-toluenesulfonic acid and concentrated sulfuric acid, and the mass ratio of p-toluenesulfonic acid to concentrated sulfuric acid is 1:4.

[0055] Figure 2 The infrared spectrum of polycitric acid obtained in step S1 of Example 1 is shown in FT-IR (KBr, cm⁻¹). -1 ):3283,(-NH stretching vibration)3114(=CH stretching vibration),1702(-C=0 stretching vibration)1536(-NH deformation vibration).

[0056] Figure 3 The infrared spectrum of the polyciconimidin oligomer obtained in Example 1 is shown in FT-IR (KBr, cm⁻¹): 3471 (-C=O stretching vibration absorption peak (overtone)), 1710 (-C=O stretching vibration), 1512, 1394 (-CNC- stretching vibration).

[0057] Figure 4 The 1H NMR spectrum of the polyciconimide oligomer obtained in Example 1 is shown below; 1H NMR (600MHz, CDCl3) δ 7.32-7.02 (Ar-H), 6.48-6.42 (C=CH), 4.05-3.87 (CH2), 2.18-1.99 (CH3).

[0058] Example 2

[0059] The specific implementation method of this example is the same as that of Example 1, except that the amount of catalyst added in step S2 is 20g, the catalyst is p-toluenesulfonic acid and acetic acid, and the mass ratio of p-toluenesulfonic acid and acetic acid is 1:3.

[0060] The polyciconimidin oligomer prepared in this example (179.3 g) had a product yield of 93.4%. The softening point was 83.7 °C, and the acid value was 0.77 mg KOH / g.

[0061] Examples 3-7, Comparative Examples 1-6

[0062] Examples 3-7 and Comparative Examples 1-6 each provide a rubber composition. The raw materials and amounts used are shown in Tables 1-3. In the tables, " / " indicates that no such raw material is added.

[0063] The specific implementation method of the polyciconimidin oligomer and its preparation method in Example 3 is the same as that in Example 1, except that the solvent in step S1 is chlorobenzene.

[0064] The polyciconimidin oligomer prepared in this example (173.5 g) had a product yield of 90.4%. The softening point was 82.8 °C, and the acid value was 0.91 mg KOH / g.

[0065] The specific implementation method of the polycitidine imide oligomer and its preparation method in Example 4 is the same as that in Example 1, except that the amount of citrine anhydride added in step S1 is (137.0g, 1.22mol).

[0066] The polyciconimidin oligomer prepared in this example (177.4 g) had a product yield of 92.4%. The softening point was 82.5 °C, and the acid value was 1.02 mg KOH / g.

[0067] Table 1

[0068]

[0069] Table 2

[0070]

[0071]

[0072] Table 3

[0073]

[0074] A method for preparing the rubber composition includes: plasticizing diene rubber for 30 seconds at a speed of 60 r / min, then adding fillers and rubber additives and mixing for 100-180 seconds at a temperature of 150°C, then adding stearic acid, zinc oxide, antioxidant, and protective wax and mixing at a temperature of 155°C for 120 seconds, then feeding the mixed rubber into a two-roll mill, mixing it evenly, then adding sulfur and accelerator, dispersing it evenly, then forming five triangular rolls, then adjusting the roll gap to 3 mm, and finally sheeting the rubber compound to obtain the rubber composition.

[0075] Performance testing

[0076] The samples prepared in Examples 3-7 and Comparative Examples 1-6 were vulcanized in a flat vulcanizing machine. The vulcanization conditions for tensile test specimens were 150°C for 20 min, and the vulcanization conditions for other vulcanized test specimens were 150°C for 25 min. The test contents and data are shown in Tables 4-6.

[0077] Test methods and standards:

[0078] 1) Hardness: According to GB / T531 Test Method for Indentation Hardness of Vulcanized Rubber or Thermoplastic Rubber, the test temperature is room temperature.

[0079] 2) Mechanical properties: According to GB / T528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber, the test temperature is room temperature.

[0080] 3) Tear strength: According to GB / T529-2008 Determination of tear strength of vulcanized rubber or thermoplastic rubber, the test temperature is room temperature.

[0081] 4) Dynamic cut resistance: The test was conducted using an RCC-I type rubber dynamic cut resistance tester. This tester uses a specially designed blade to repeatedly impact a rotating, circular rubber sample with a certain amount of energy. The test results are expressed as the volume difference of the rubber sample before and after the test; the larger the value, the worse the performance.

[0082] 5) Aging coefficient: Rubber is aged in an aging chamber at 100℃ for 48 hours. The higher the aging coefficient, the better the heat and oxygen aging resistance.

[0083] 6) Dynamic performance: The dynamic tensile properties were tested using a DMA850 device under the following conditions: frequency of 10 Hz, deformation of 0.25%, temperature range of -80℃ to +70℃, and heating rate of 1.5℃ / min.

[0084] 7) Crosslinking density: The vulcanization characteristics are determined using a rotorless vulcanizer according to GB / T16584-1996. The higher the MH-ML value, the higher the crosslinking network density.

[0085] 8) Reversion rate: Rt=(MH-Mt) / (MH-ML)100%, where Rt represents the degree of reversion of the over-cured rubber over a long period of time. The smaller the value, the smaller the degree of reversion at time t.

[0086] 9) Resilience: According to GB / T 1681-2009 Test of Resilience of Vulcanized Rubber, the higher the value, the better the resilience.

[0087] 10) Flexural fatigue: Determination of flexural cracking and crack growth of vulcanized rubber or thermoplastic rubber (Demercia type) according to GB / T-13934-2006.

[0088] 11) Compression set: Determination of compression set of vulcanized rubber or thermoplastic rubber in accordance with GB / T-7759.1-2015.

[0089] Table 4

[0090] Performance testing Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 3 Example 4 Crosslinking density (MH-ML value) 10.09 10.72 11.94 11.14 12.91 Vulcanization reversion rate R60,% 17.8 4.2 3.2 4.5 2.9 100% constant tensile stress / MPa 1.9 2 2.1 2.1 2.3 300% constant tensile stress / MPa 10.9 11.1 11.2 11.7 12.2 Tensile strength / MPa 26.4 26.7 27.8 27.4 28.3 Hardness (Shore A) 60 60 61 62 65 Tear strength kN / m 113.9 104.0 126.2 142.5 156.0 Dynamic performance (tanδ, 60℃) 0.143 0.153 0.167 0.140 0.137 <![CDATA[Dynamic cut-resistant volume / cm 3 > 1.627 1.609 1.588 1.581 1.533 Aging coefficient % 53％ 55％ 58％ 63％ 67％

[0091] As can be seen from the data in Table 4, the polyciconimide oligomer in this application has superior anti-sulfurization reversion properties compared to bisciconimide. It can improve crosslinking density, hardness, tensile modulus and tear strength more than bisciconimide, while also resulting in lower hysteresis loss.

[0092] Table 5

[0093] Performance testing Comparative Example 4 Example 5 Example 6 Crosslinking density (MH-ML value) 45.81 41.41 46.02 100% constant tensile stress / MPa 6.9 7.3 7.5 Tensile strength / MPa 14.1 20.3 19.6 Hardness (Shore A) 89 84 88 Tear strength kN / m 47.1 51.5 54.3 Dynamic performance (tanδ, 60℃) 0.097 0.084 0.082 Aging coefficient % 63％ 68％ 69％

[0094] As can be seen from the test data in Table 5, both the polyciconimide oligomer and the phenolic reinforcing resin in this application have excellent reinforcing properties. However, the polyciconimide oligomer prepared in this application can improve the modulus and tear strength, while also resulting in lower hysteresis loss.

[0095] Table 6

[0096] Performance testing Comparative Example 4 Example 5 Example 6 Crosslinking density (MH-ML value) 14.29 15.03 15.54 Vulcanization reversion rate R60,% 14.3 5.2 4.8 Hardness (Shore A) 56 57 58 100% constant tensile stress / MPa 2 2.3 2.4 300% constant tensile stress / MPa 12.5 12.9 13.5 Tensile strength / MPa 24.9 25 26.2 Tear strength kN / m 60.4 70.44 75.4 Dynamic performance (tanδ, 60℃) 0.0639 0.0581 0.0555 Rebound (%) 69 69 70 Grade 1 flexion fatigue (10,000 cycles) 80 100 100 Level 6 flexion fatigue (10,000 cycles) 100 140 160 Compression set (%) 38 34 33

[0097] As can be seen from the test data in Table 6, the polyciconimide oligomer in this application improves crosslinking density, hardness, modulus, tear strength, and resilience, while exhibiting small permanent deformation and significantly improved flexural fatigue performance.

Claims

1. A polyciconimidin oligomer, characterized in that, The general structural formula of the polyciconimidin oligomer is: R1 and R2 are both selected from hydrogen atoms, halogen atoms, nitro groups, and C1-C atoms. 20 aliphatic groups or their derivatives, C6-C 12 One of the aromatic hydrocarbon alkyl groups or their derivatives; n is an integer from 0 to 30.

2. A method for preparing the polyciconimidin oligomer according to claim 1, characterized in that, At least including: S1, citrile anhydride reacts with polyamines to produce polycitralic acid; S2. The polycitamide acid is dehydrated and cyclized under the action of a catalyst to generate polycitamide oligomer.

3. The preparation method according to claim 2, characterized in that, The molar ratio of citralic anhydride to amino groups in the polyamine is (1-1.2):

1.

4. The preparation method according to claim 2, characterized in that, The molar ratio of the catalyst to the amino groups in the polyamine is (0.01-0.8):

1.

5. The preparation method according to claim 2, characterized in that, The catalyst includes at least one of acetic acid, sulfuric acid, phosphoric acid, p-toluenesulfonic acid, methanesulfonic acid, benzenesulfonic acid, p-chlorobenzenesulfonic acid, p-nitrobenzenesulfonate acid, formic acid, zinc chloride, ferric chloride, and aluminum chloride.

6. A rubber composition, characterized in that, The raw materials used in the preparation include the polyciconimidin oligomer as described in claim 1.

7. The rubber composition according to claim 6, characterized in that, The raw materials for preparing the rubber composition, by weight, include: 100 parts of diene rubber, 10-120 parts of filler, 0.01-30 parts of rubber additive, 1-10 parts of sulfur, 0.5-2 parts of accelerator, 1-5 parts of stearic acid, 3-12 parts of zinc oxide, 1-5 parts of antioxidant, and 1-5 parts of protective wax, wherein the rubber additive is polycitidine oligomer.

8. The rubber composition according to claim 7, characterized in that, The diene-based rubber includes at least one of natural rubber and diene-based synthetic rubber.

9. The rubber composition according to claim 7, characterized in that, The filler includes at least one of carbon black and silica.

10. An application of a rubber composition according to any one of claims 6-8, characterized in that, The rubber composition is used in the preparation of tire components, shock-absorbing components, and seals.

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