A liquid hindered phenolic antioxidant and its preparation method and application

Abstract

The application discloses a kind of liquid hindered phenol antioxidant and its preparation method and application, the molecular structure of the liquid hindered phenol antioxidant is: R1, R2 It is C1~C8 alkyl, R3 is C1~C5 alkylidene group, the R4 group is the organic group that is retained in ester structure after esterification or ester exchange reaction of fatty alcohol;The liquid hindered phenol antioxidant prepared in the application not only can effectively inhibit the generation of aldehyde in the storage process of polyether, also has certain heat resistance antioxidant property and thermal stability, and has excellent compatibility with polyurethane foam, especially suitable for polyurethane soft foam plate.

Description

Technical Field

[0001] The present invention belongs to the field of antioxidants for polymer materials, with the classification number being C07C67 / 03. Specifically, the present invention relates to a liquid hindered phenol antioxidant, a preparation method thereof, and an application thereof. Background Art

[0002] Polyurethane materials offer excellent performance, a wide range of adjustments, and strong adaptability, making them widely used in numerous sectors of the national economy, particularly in automotive polyurethane foam. With the improvement of people's living standards, cars have become one of the primary places people spend their time, besides their homes and workplaces. However, polyurethane foam is inevitably exposed to heat, light, air, oxygen, and water during use, which can lead to degradation and degradation of its performance, ultimately rendering it useless. Therefore, antioxidants are commonly added to prevent the aging and decomposition of polyurethane foam.

[0003] Currently available antioxidants mainly include hindered phenolic antioxidants, phosphite antioxidants, and thioester antioxidants. Among them, hindered phenolic antioxidants are one of the most widely used and effective antioxidants. However, while current hindered phenolic antioxidants, such as Antioxidant 1076, can prevent the aging and decomposition of polyurethane foam to a certain extent, they are solid and are not well compatible with polyurethane foam during use, which greatly reduces their antioxidant performance. Therefore, the market demand for liquid hindered phenolic antioxidants is greatly increasing.

[0004] However, there are certain difficulties in developing liquid hindered phenol antioxidants for polyurethane foam. First, polyurethane foam needs to have a certain compatibility with the antioxidant. Second, even if the compatibility between the antioxidant and polyurethane foam is met, various factors such as molecular weight, volatility and dispersibility may also affect its antioxidant effect. Therefore, on the basis of the above, overcoming the defects of existing liquid hindered phenol antioxidants and improving heat resistance stability are the problems to be solved by the present invention.

[0005] Patent application number CN1247737C develops a liquid antioxidant and a preparation method thereof. The main advantages of the liquid antioxidant are high carbon number, low volatility, and low freezing point. Although it describes good compatibility with materials, it does not describe the specific composition of the materials.

[0006] Patent application number CN113264869B develops a hindered phenol antioxidant and its preparation method, which solves the problem of phenolic antioxidants being easily volatilized and lost when heated during processing and use, and also has good compatibility with non-polar polymers. However, this hindered phenol antioxidant is mainly used in natural rubber, which is significantly different from the present application. Summary of the Invention

[0007] In order to solve the above problems, the first aspect of the present invention provides a liquid hindered phenol antioxidant, the molecular structure of the liquid hindered phenol antioxidant is:

[0008] The R1 and R2 are C1-C8 alkyl groups, R3 is a C1-C5 alkylene group, and the R4 group is an organic group remaining in the ester structure after the esterification or transesterification reaction of the fatty alcohol.

[0009] Further preferably, R1 and R2 are C4 tert-butyl groups, R3 is a C2 alkylene group, and R4 is an organic group retained in the ester structure after the isomeric 18-alcohol undergoes an ester exchange reaction.

[0010] Preferably, the relative molecular mass of the liquid hindered phenol antioxidant is 400-800.

[0011] More preferably, the relative molecular mass of the liquid hindered phenol antioxidant is 400-600.

[0012] More preferably, the relative molecular mass of the liquid hindered phenol antioxidant is 530.

[0013] Preferably, the raw materials for preparing the liquid hindered phenol antioxidant include, by weight, 100-200 parts of branched fatty alcohol, 1-4 parts of catalyst, and 90-150 parts of organic antioxidant.

[0014] Further preferably, the raw materials for preparing the liquid hindered phenol antioxidant include, by weight, 100-150 parts of branched fatty alcohol, 1-3 parts of catalyst, and 90-100 parts of organic antioxidant.

[0015] Further preferably, the raw materials for preparing the liquid hindered phenol antioxidant include, by weight, 110 parts of branched fatty alcohol, 2 parts of catalyst, and 95 parts of organic antioxidant.

[0016] Preferably, the branched fatty alcohol is C 16 -C 25 Branched chain fatty alcohols.

[0017] Further preferably, the branched fatty alcohol is C 18 -C 24 Branched chain fatty alcohols.

[0018] Further preferably, the branched fatty alcohol is C 18 -C 20 Branched chain fatty alcohols.

[0019] Further preferably, the branched fatty alcohol is C 18 Branched chain fatty alcohols.

[0020] Further preferably, the C 18 The branched-chain fatty alcohols are isomeric 18-ols.

[0021] Preferably, the catalyst comprises at least one of alkoxy aluminum, alkali metal compounds, phenoxy aluminum, organic tin compounds and organic zinc salts.

[0022] More preferably, the catalyst is an organotin compound.

[0023] More preferably, the catalyst is monobutyltin oxide.

[0024] Preferably, the organic antioxidant is 3,5-methyl ester.

[0025] Preferably, the molar ratio between the organic antioxidant and the branched fatty alcohol is (1-1.5):1.

[0026] More preferably, the molar ratio between the organic antioxidant and the branched fatty alcohol is (1-1.2):1.

[0027] More preferably, the molar ratio between the organic antioxidant and the branched fatty alcohol is 1.1:1.

[0028] The second aspect of the present invention provides a method for preparing a liquid hindered phenol antioxidant, comprising the following steps:

[0029] Add organic antioxidant, catalyst and branched fatty alcohol into the reaction device according to weight, gradually increase the temperature to 0.08-0.1MPa, react for a period of time, evaporate excess methanol, cool to 25-35°C, filter out the catalyst, and obtain the product.

[0030] Preferably, the reaction temperature after heating is 150-180° C., and the reaction time is 5-9 hours.

[0031] More preferably, the reaction temperature after heating is 160-170° C., and the reaction time is 6-8 h.

[0032] More preferably, the reaction temperature after heating is 165° C. and the reaction time is 7 h.

[0033] A third aspect of the present invention provides an application of a liquid hindered phenol antioxidant in automotive polyurethane foam.

[0034] The present invention also provides a preparation method of an organic antioxidant, which comprises the following steps: adding 2776 kg of 2,6-di-tert-butylphenol to a drying kettle at 100° C. and dehydrating for 1.5 hours, performing nitrogen replacement three times, raising the temperature to 125° C., adding 40 kg of sodium methoxide as a catalyst, reacting for 1.5 hours, adding 1110 kg of methyl acrylate, reacting for 2.5 hours, and then keeping the temperature at 125° C. for 5.5 hours. Then, adding 20 kg of formic acid to neutralize the alkaline catalyst and filtering the mixture. Then, adding methanol for crystallization, and washing and filtering the mixture to obtain the organic antioxidant.

[0035] The applicant has found that the liquid hindered phenol antioxidant prepared by the present invention is an asymmetric phenol antioxidant, wherein the ortho-substituents are all tert-butyl, and the para-substituent is C 18- C 24 The isomerized branched chain, which is a long-chain alkane, is not only more compatible with polyurethane, but also surprisingly found to be able to improve its thermal stability and heat and oxidation resistance to a certain extent. It is speculated that this is due to the C 18- C 24 The isomeric side chains are electron-donating groups, which can accelerate the separation of hydrogen atoms on the phenolic hydroxyl groups, thereby improving the antioxidant activity. In addition, the ortho-tert-butyl groups on both sides make the benzene ring and the phenolic hydroxyl groups not on the same plane, thereby making it difficult for the electrons on the oxygen atom P orbital to conjugate with the electrons on the benzene ring, further improving its heat resistance and antioxidant properties. Although the larger steric hindrance of the ortho-tert-butyl group can protect the phenoloxy free radicals to a certain extent, its thermal stability is improved to a certain extent, but the ortho-tert-butyl and para-substituents are C 18- C 24 The steric hindrance effect of the isomeric side chains is too high, which may reduce its heat resistance and oxidation resistance. Therefore, the relative molecular mass of the antioxidant is limited to only 400-600. While ensuring the steric hindrance effect of the ortho-substituents, it also avoids the reduction of its heat resistance and oxidation resistance due to too strong steric hindrance effect.

[0036] Beneficial effects:

[0037] (1) The liquid hindered phenol antioxidant prepared by the present invention can effectively inhibit the generation of aldehydes in polyether during storage, and has excellent compatibility with polyurethane foam, and can provide polyurethane foam with excellent anti-core burning and anti-ultraviolet properties, as well as certain heat resistance, antioxidant properties and thermal stability, and is particularly suitable for polyurethane soft foam sheets.

[0038] (2) The liquid hindered phenol antioxidant prepared by the present invention has low volatility, which prevents fogging on the surface of polyurethane products used in automobiles and can also avoid the coloring problem of textiles.

[0039] (3) The liquid hindered phenol antioxidant prepared by the present invention is in liquid form, which is convenient for transportation and use, and can be dissolved, dispersed or maintained in a pure liquid state during processing, greatly improving its practicality. Example

[0040] Example 1

[0041] A liquid hindered phenol antioxidant, wherein the molecular structure of the liquid hindered phenol antioxidant is:

[0042]

[0043] The R1 and R2 are C4 tert-butyl groups, the R3 is a C2 alkylene group, and the R4 group is an organic group remaining in the ester structure after the isomeric 18-alcohol undergoes an ester exchange reaction.

[0044] The molecular weight of the liquid hindered phenol antioxidant is 530.

[0045] The raw materials for preparing the liquid hindered phenol antioxidant include, by weight, 110 parts of branched fatty alcohol, 2 parts of catalyst, and 95 parts of organic antioxidant.

[0046] The branched fatty alcohol is isomeric 18-alcohol purchased from Sasol, Germany, with the model number being ISOFOL 18T.

[0047] The catalyst is monobutyltin oxide.

[0048] The organic antioxidant is 3,5-methyl ester.

[0049] The molar ratio between the organic antioxidant and the branched fatty alcohol is 1.1:1.

[0050] The second aspect of this embodiment provides a method for preparing a liquid hindered phenol antioxidant, comprising the following steps:

[0051] Add the organic antioxidant, catalyst and branched fatty alcohol to the reaction device according to weight, gradually increase the temperature to 165°C and then increase the pressure to 0.09 MPa, react for 7 hours, evaporate the excess methanol, cool to 30°C, filter out the catalyst monobutyl tin oxide, and obtain the product.

[0052] The third aspect of this embodiment provides an application of a liquid hindered phenol antioxidant in automotive polyurethane foam.

[0053] This embodiment also provides a method for preparing an organic antioxidant, comprising the following steps: adding 2776 kg of 2,6-di-tert-butylphenol to a drying kettle at 100° C. and dehydrating for 1.5 hours, performing nitrogen replacement three times, raising the temperature to 125° C., adding 40 kg of sodium methoxide catalyst, reacting for 1.5 hours, adding 1110 kg of methyl acrylate, reacting for 2.5 hours, and then keeping the temperature at 125° C. for 5.5 hours. Then, adding 20 kg of formic acid to neutralize the alkaline catalyst, filtering, adding methanol for crystallization, and washing and filtering to obtain the product.

[0054] Example 2

[0055] A liquid hindered phenol antioxidant, wherein the molecular structure of the liquid hindered phenol antioxidant is:

[0056]

[0057] The R1 and R2 are C4 tert-butyl groups, the R3 is a C2 alkylene group, and the R4 group is an organic group remaining in the ester structure after the isomeric 20-ol undergoes an ester exchange reaction.

[0058] The molecular weight of the liquid hindered phenol antioxidant is 558.

[0059] The raw materials for preparing the liquid hindered phenol antioxidant include, by weight, 110 parts of branched fatty alcohol, 2 parts of catalyst, and 95 parts of organic antioxidant.

[0060] The branched fatty alcohol is ISOFOL 20, purchased from Sasol, Germany, with the model number being ISOFOL 20.

[0061] The catalyst is monobutyltin oxide.

[0062] The organic antioxidant is 3,5-methyl ester.

[0063] The molar ratio between the organic antioxidant and the branched fatty alcohol is 1.1:1.

[0064] The second aspect of this embodiment provides a method for preparing a liquid hindered phenol antioxidant, comprising the following steps:

[0065] Add the organic antioxidant, catalyst and branched fatty alcohol to the reaction device according to weight, gradually increase the temperature to 165°C and then increase the pressure to 0.09 MPa, react for 7 hours, evaporate the excess methanol, cool to 30°C, filter out the catalyst monobutyl tin oxide, and obtain the product.

[0066] The third aspect of this embodiment provides an application of a liquid hindered phenol antioxidant in automotive polyurethane foam.

[0067] This embodiment also provides a method for preparing an organic antioxidant, comprising the following steps: adding 2776 kg of 2,6-di-tert-butylphenol to a drying kettle at 100° C. and dehydrating for 1.5 hours, performing nitrogen replacement three times, raising the temperature to 125° C., adding 40 kg of sodium methoxide catalyst, reacting for 1.5 hours, adding 1110 kg of methyl acrylate, reacting for 2.5 hours, and then keeping the temperature at 125° C. for 5.5 hours. Then, adding 20 kg of formic acid to neutralize the alkaline catalyst, filtering, adding methanol for crystallization, and washing and filtering to obtain the product.

[0068] Example 3

[0069] A liquid hindered phenol antioxidant, wherein the molecular structure of the liquid hindered phenol antioxidant is:

[0070]

[0071] The R1 and R2 are C4 tert-butyl groups, the R3 is a C2 alkylene group, and the R4 group is an organic group retained in the ester structure after the isomeric 24-alcohol undergoes an ester exchange reaction.

[0072] The molecular weight of the liquid hindered phenol antioxidant is 614.

[0073] The raw materials for preparing the liquid hindered phenol antioxidant include, by weight, 110 parts of branched fatty alcohol, 2 parts of catalyst, and 95 parts of organic antioxidant.

[0074] The branched fatty alcohol is isomeric 24-alcohol purchased from Sasol, Germany, with the model number being ISOFOL 24.

[0075] The catalyst is monobutyltin oxide.

[0076] The organic antioxidant is 3,5-methyl ester.

[0077] The molar ratio between the organic antioxidant and the branched fatty alcohol is 1.1:1.

[0078] The second aspect of this embodiment provides a method for preparing a liquid hindered phenol antioxidant, comprising the following steps:

[0079] Add the organic antioxidant, catalyst and branched fatty alcohol to the reaction device according to weight, gradually increase the temperature to 165°C and then increase the pressure to 0.09 MPa, react for 7 hours, evaporate the excess methanol, cool to 30°C, filter out the catalyst monobutyl tin oxide, and obtain the product.

[0080] The third aspect of this embodiment provides an application of a liquid hindered phenol antioxidant in automotive polyurethane foam.

[0081] This embodiment also provides a method for preparing an organic antioxidant, comprising the following steps: adding 2776 kg of 2,6-di-tert-butylphenol to a drying kettle at 100° C. and dehydrating for 1.5 hours, performing nitrogen replacement three times, raising the temperature to 125° C., adding 40 kg of sodium methoxide catalyst, reacting for 1.5 hours, adding 1110 kg of methyl acrylate, reacting for 2.5 hours, and then keeping the temperature at 125° C. for 5.5 hours. Then, adding 20 kg of formic acid to neutralize the alkaline catalyst, filtering, adding methanol for crystallization, and washing and filtering to obtain the product.

[0082] Comparative Example 1

[0083] A liquid hindered phenol antioxidant, wherein the molecular structure of the liquid hindered phenol antioxidant is:

[0084]

[0085] The R1 and R2 are C4 tert-butyl groups, the R3 is a C2 alkylene group, and the R4 group is an organic group remaining in the ester structure after the isomeric 12-ol undergoes an ester exchange reaction.

[0086] The molecular weight of the liquid hindered phenol antioxidant is 446.

[0087] The raw materials for preparing the liquid hindered phenol antioxidant include, by weight, 110 parts of branched fatty alcohol, 2 parts of catalyst, and 95 parts of organic antioxidant.

[0088] The branched fatty alcohol is isomeric 12-alcohol purchased from Sasol, Germany, with the model number being ISOFOL 12.

[0089] The catalyst is monobutyltin oxide.

[0090] The organic antioxidant is 3,5-methyl ester.

[0091] The molar ratio between the organic antioxidant and the branched fatty alcohol is 1.1:1.

[0092] The second aspect of this embodiment provides a method for preparing a liquid hindered phenol antioxidant, comprising the following steps:

[0093] Add the organic antioxidant, catalyst and branched fatty alcohol to the reaction device according to weight, gradually increase the temperature to 165°C and then increase the pressure to 0.09 MPa, react for 7 hours, evaporate the excess methanol, cool to 30°C, filter out the catalyst monobutyl tin oxide, and obtain the product.

[0094] The third aspect of this embodiment provides an application of a liquid hindered phenol antioxidant in automotive polyurethane foam.

[0095] This embodiment also provides a method for preparing an organic antioxidant, comprising the following steps: adding 2776 kg of 2,6-di-tert-butylphenol to a drying kettle at 100° C. and dehydrating for 1.5 hours, performing nitrogen replacement three times, raising the temperature to 125° C., adding 40 kg of sodium methoxide catalyst, reacting for 1.5 hours, adding 1110 kg of methyl acrylate, reacting for 2.5 hours, and then keeping the temperature at 125° C. for 5.5 hours. Then, adding 20 kg of formic acid to neutralize the alkaline catalyst, filtering, adding methanol for crystallization, and washing and filtering to obtain the product.

[0096] Comparative Example 2

[0097] A liquid hindered phenol antioxidant, wherein the molecular structure of the liquid hindered phenol antioxidant is:

[0098]

[0099] The R1 and R2 are C4 tert-butyl groups, the R3 is a C2 alkylene group, and the R4 group is an organic group remaining in the ester structure after the ester exchange reaction of n-eicosanol.

[0100] The molecular weight of the liquid hindered phenol antioxidant is 558.

[0101] The raw materials for preparing the liquid hindered phenol antioxidant include, by weight, 110 parts of branched fatty alcohol, 2 parts of catalyst, and 95 parts of organic antioxidant.

[0102] The branched-chain fatty alcohol is n-eicosanol.

[0103] The catalyst is monobutyltin oxide.

[0104] The organic antioxidant is 3,5-methyl ester.

[0105] The molar ratio between the organic antioxidant and the branched fatty alcohol is 1.1:1.

[0106] The second aspect of this embodiment provides a method for preparing a liquid hindered phenol antioxidant, comprising the following steps:

[0107] Add the organic antioxidant, catalyst and branched fatty alcohol to the reaction device according to weight, gradually increase the temperature to 165°C and then increase the pressure to 0.09 MPa, react for 7 hours, evaporate the excess methanol, cool to 30°C, filter out the catalyst monobutyl tin oxide, and obtain the product.

[0108] The third aspect of this embodiment provides an application of a liquid hindered phenol antioxidant in automotive polyurethane foam.

[0109] This embodiment also provides a method for preparing an organic antioxidant, comprising the following steps: adding 2776 kg of 2,6-di-tert-butylphenol to a drying kettle at 100° C. and dehydrating for 1.5 hours, performing nitrogen replacement three times, raising the temperature to 125° C., adding 40 kg of sodium methoxide catalyst, reacting for 1.5 hours, adding 1110 kg of methyl acrylate, reacting for 2.5 hours, and then keeping the temperature at 125° C. for 5.5 hours. Then, adding 20 kg of formic acid to neutralize the alkaline catalyst, filtering, adding methanol for crystallization, and washing and filtering to obtain the product.

[0110] Comparative Example 3

[0111] A liquid hindered phenol antioxidant, wherein the molecular structure of the liquid hindered phenol antioxidant is:

[0112]

[0113] The R1 is a tert-butyl group of C4, the R2 is a methyl group of C1, the R3 is an alkylene group of C2, and the R4 group is an organic group retained in the ester structure after the isomeric 18-alcohol undergoes an ester exchange reaction.

[0114] The molecular weight of the liquid hindered phenol antioxidant is 488.

[0115] The raw materials for preparing the liquid hindered phenol antioxidant include, by weight, 110 parts of branched fatty alcohol, 2 parts of catalyst, and 95 parts of organic antioxidant.

[0116] The branched fatty alcohol is isomeric 18-alcohol purchased from Sasol, Germany, with the model number being ISOFOL 18T.

[0117] The catalyst is monobutyltin oxide.

[0118] The organic antioxidant is methyl 3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, which is purchased from Jinjinle (Hunan) Chemical Co., Ltd.

[0119] The molar ratio between the organic antioxidant and the branched fatty alcohol is 1.1:1.

[0120] The second aspect of this embodiment provides a method for preparing a liquid hindered phenol antioxidant, comprising the following steps:

[0121] Add the organic antioxidant, catalyst and branched fatty alcohol to the reaction device according to weight, gradually increase the temperature to 165°C and then increase the pressure to 0.09 MPa, react for 7 hours, evaporate the excess methanol, cool to 30°C, filter out the catalyst monobutyl tin oxide, and obtain the product.

[0122] The third aspect of this embodiment provides an application of a liquid hindered phenol antioxidant in automotive polyurethane foam.

[0123] This embodiment also provides a method for preparing an organic antioxidant, comprising the following steps: adding 2776 kg of 2,6-di-tert-butylphenol to a drying kettle at 100° C. and dehydrating for 1.5 hours, performing nitrogen replacement three times, raising the temperature to 125° C., adding 40 kg of sodium methoxide catalyst, reacting for 1.5 hours, adding 1110 kg of methyl acrylate, reacting for 2.5 hours, and then keeping the temperature at 125° C. for 5.5 hours. Then, adding 20 kg of formic acid to neutralize the alkaline catalyst, filtering, adding methanol for crystallization, and washing and filtering to obtain the product.

[0124] Performance evaluation

[0125] 1. Oxidation induction period test and anti-burning test:

[0126] Oxidation Induction Period Test: After stirring the polyether and 4000ppm of a liquid hindered phenolic antioxidant (ST-1912) at 25°C for 10 minutes, the oxidation induction period was measured using a Shanghai Hesheng HS-DSC-101 Oxidation Induction Period Tester. First, in a pure nitrogen atmosphere, the temperature was set to 50°C and held for 1 minute before heating at a controlled rate of 40°C / min. After 3 minutes, the temperature was raised to 170°C and held for 3 minutes. The temperature was then switched to a pure oxygen atmosphere with an oxygen purity of at least 99.99%. The test was stopped when the curve showed a significant rise during heat release.

[0127] b Foam core burning test: Cut the prepared polyurethane foam into 100*50*10mm specifications and place it in an electric constant temperature blower at 165℃. Take it out after 5 hours and read the ΔB value using PRECISION COLORIMETER NR10QC instrument.

[0128] Table 1

[0129]

[0130] The hindered phenol antioxidant (ST-1912) in Example 1 was tested for its initial oxidation temperature: a. Initial oxidation temperature test: After the polyether and 4000 ppm of liquid hindered phenol antioxidant (ST-1912) were stirred at 25°C for 10 min, the mixture was measured using a Netzsch DSC204HP differential scanning calorimeter with a heating rate of 10°C / min and an oxygen purity of 99.99% or above. The test results are shown in Table 2 below.

[0131] Table 2

[0132]

[0133] The antioxidants 1076 and 1135 described in the present invention are both commercially available.

[0134] 2. Foaming test:

[0135] Table 2 Polyurethane foaming formula

[0136] polyether 100 antioxidants 0.4 silicone oil 1 A1 0.06 33LV 0.1 water 4 T9 0.21 TDI 52.1

[0137] Preparation method of polyurethane: Take 100g of polyether and place it in a plastic cup, add 0.4g of antioxidant ST-1912 (prepared in Example 1), 1g of silicone oil, 0.16g of Al / 33LV, and 4g of water, start the stirrer, set the speed to 1500-2000rpm / min, stir for 1min, then add T90.21g, continue stirring for 15s, add weighed TDI 52.1g, stir for 8s, pour into a foaming box, and mature for 24h at a temperature of 35-40°C.

[0138] The polyether was purchased from Xindian Chemical Materials Co., Ltd., with a hydroxyl value of 56 mgKOH / g. The T9 is T9 polyurethane foam glue, purchased from Daoxing Supply Chain Management Co., Ltd. The 33LV is a polyurethane amine foaming catalyst, purchased from Evonik, model Dabco 33LV. The A1 is A1 type polyurethane foam glue, purchased from Langfang Kunchuang Energy Saving Technology Co., Ltd.

[0139] a UV test: The prepared polyurethane foam was cut into pieces of 100*30*10 mm in size and then placed in a UV oven at 50°C for 12 h. The ΔB value was then measured using a PRECISION COLORIMETER NR10QC instrument.

[0140] b. Phenol yellow test: Cut the prepared polyurethane foam into 100*30*10mm specifications, then wrap the polyurethane foam with phenol yellow test paper, separate the layers one by one, and then separate them with thin glass sheets. Wrap it with plastic paper, seal it with transparent tape, and place it in a phenol yellow test box. Maintain a constant temperature of 50℃ for 16 hours, then take it out and read the ΔB value using a PRECISION COLORIMETERNR10QC instrument.

[0141] c Foam placement test: The prepared polyurethane foam was cut into pieces of 300*150*10 mm in size and placed on a mesh stainless steel rack for 48 hours. The ΔB value was then read using a PRECISION COLORIMETER NR10QC instrument.

[0142] d. Hot Press Test: The prepared polyurethane foam was cut into 300 x 200 x 10 mm squares. The hot press temperature was set at 205°C, with the lower mold temperature at 215°C. After 300 seconds, the polyurethane foam was removed and the ΔB value was measured using a PRECISION COLORIMETER NR10QC instrument. (Antioxidants 1135 and 1076 in Table 3 are commercially available.)

[0143] Table 3

[0144]

[0145] 3. Prepolymer test: Take 100g of polyether with a hydroxyl value of 56mgKOH / g, add it to a 250mL three-necked flask, add 0.15g of antioxidant ST-1912 (prepared in Example 1), stir for 10min, and then heat to 80°C. Then, add 17.2g of TDI dropwise, keep the temperature at 80°C, and stabilize for 30min until it becomes colorless and transparent. Then, put it into an oven and bake it continuously at 80°C for 24h. After that, observe whether the liquid turns yellow. If it turns yellow, it is unqualified; otherwise, it is qualified.

[0146] name Appearance 1135 qualified 1076 Unqualified ST-1912 qualified

Claims

1. A liquid hindered phenol antioxidant, characterized in that The molecular structure of the liquid hindered phenol antioxidant is: ， The R1 and R2 are C4 tert-butyl groups, R3 is a C2 alkylene group, and the R4 group is an organic group retained in the ester structure after the isomeric 18-alcohol undergoes an ester exchange reaction; the relative molecular mass of the liquid hindered phenol antioxidant is 530; The raw materials for preparing the liquid hindered phenol antioxidant include, by weight, 110 parts of branched fatty alcohol, 2 parts of catalyst, and 95 parts of organic antioxidant; The branched fatty alcohol is isomeric 18 alcohol purchased from Sasol, Germany, model number isofoli 18T; The catalyst is monobutyltin oxide; the organic antioxidant is 3,5-methyl ester; the molar ratio between the organic antioxidant and the branched fatty alcohol is 1.1:1; The preparation method of the organic antioxidant comprises the following steps: adding 2776 kg of 2,6-di-tert-butylphenol to a drying kettle at 100° C. and dehydrating for 1.5 hours, performing nitrogen replacement three times, raising the temperature to 125° C., adding 40 kg of sodium methoxide catalyst, reacting for 1.5 hours, adding 1110 kg of methyl acrylate, reacting for 2.5 hours, then keeping the temperature at 125° C. for 5.5 hours, adding 20 kg of formic acid to neutralize the alkaline catalyst, filtering, adding methanol for crystallization, washing, and filtering to obtain the organic antioxidant; The preparation method of the liquid hindered phenol antioxidant comprises the following steps: Add organic antioxidant, catalyst and branched fatty alcohol into the reaction device according to weight, gradually increase the temperature to 165°C and then increase the pressure to 0.09MPa, react for 7h, evaporate the excess methanol, cool to 30°C, filter out the catalyst monobutyltin oxide, and obtain the product.

2. Use of the liquid hindered phenol antioxidant according to claim 1 in automotive polyurethane foam.

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