A rubber vulcanization accelerator and a preparation method and application thereof

Abstract

The present application relates to the technical field of rubber vulcanization, and provides a rubber vulcanization accelerator, a preparation method and application thereof.The present application provides application of the rubber vulcanization accelerator in improving the tensile strength and tear strength of rubber, and the preparation method of the rubber vulcanization accelerator comprises the following steps: acidizing treatment is performed on lignin, and then the acidized lignin is mixed with carbon disulfide and reacts under alkaline conditions; the obtained product is subjected to heat treatment to obtain the rubber vulcanization accelerator.Compared with the prior art, the rubber vulcanization accelerator has a good vulcanization promoting effect on rubber, and simultaneously produces a reinforcing effect, is a new type of environmentally-friendly multifunctional rubber additive, and can be applied to the production of rubber products.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rubber vulcanization, more particularly to a rubber vulcanization accelerator, a preparation method and application thereof. BACKGROUND

[0002] The wastewater produced by alkali cooking in pulp and paper industry is black-brown, so it is called black liquor, which is the main pollution source of papermaking industry, accounting for 90% of the pollution of papermaking industry. In addition to containing sodium hydroxide and silicon dioxide and other inorganic substances, a large amount of lignin is also dissolved in the black liquor. The traditional treatment method of black liquor is mainly to evaporate and concentrate and then burn as fuel, but it has low heat utilization efficiency, and at the same time, a large amount of greenhouse gases are generated, which will lead to the loss of potential value-added substances such as lignin contained in the black liquor. The annual output of by-product lignin in black liquor is about 500 million tons, but only 2% is utilized, and the rest is utilized as low-value fuel. Lignin is an aromatic natural polymer substance connected by alkyl-alkyl, alkyl-aryl, aryl-alkyl and other chemical bonds through benzene-alkane monomers. The molecular structure of lignin contains a large number of active groups such as aromatic group, methoxy group, alcohol hydroxyl group and phenolic hydroxyl group, so it can undergo chemical reactions such as hydrolysis, alcoholysis, acid methoxy, alkylation and hydroxymethylation. Efficient utilization of lignin in black liquor not only can solve the pollution of black liquor to the environment, but also can produce good economic benefits, which has double significance of resources and environment. SUMMARY

[0003] Therefore, the present application aims to provide a rubber vulcanization accelerator, a preparation method and application thereof. The rubber vulcanization accelerator has good vulcanization promotion and reinforcement effects on rubber, is a new type of multifunctional rubber additive with environmental protection, and can be applied to the production of rubber products.

[0004] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0005] The application of a rubber vulcanization accelerator in improving the tensile strength and tear strength of rubber, the preparation method of the rubber vulcanization accelerator comprises the following steps:

[0006] The lignin is subjected to acidification treatment, and then the acidification-treated lignin is mixed and reacted with carbon disulfide under alkaline conditions; the product obtained by the reaction is subjected to heat treatment to obtain a rubber vulcanization accelerator.

[0007] The preparation reaction process of the rubber vulcanization accelerator of the present application is as shown in Figure 1 .

[0008] The xanthate is a non-toxic and pollution-free environmental protection type rapid vulcanization accelerator which does not contain nitrogen atom in the molecular structure, so that nitrosamine is not generated in the vulcanization process.

[0009] Lignin is a complex organic substance, which can form chemical chain or hydrogen bond with active groups or double bonds of rubber molecules, and has certain reinforcing effect on rubber. The phenolic hydroxyl groups contained in the structure of lignin not only have anti-aging effect, but also can be modified for functionalization.

[0010] Preferably, the addition amount of the rubber vulcanization accelerator in rubber is 1-2wt%.

[0011] Preferably, the mass ratio of the lignin to carbon disulfide is 1:(0.5-2.0), preferably 1:1.

[0012] Preferably, the acidification treatment comprises mixing the lignin with water, then adjusting the pH to 1-6 with an acid, and then reacting at 60-100℃ for 2-50h; preferably, the pH is adjusted to 1-2 with an acid.

[0013] Preferably, in the acidification treatment, the lignin is mixed with water to a concentration of 2-5wt%.

[0014] Preferably, the acid comprises any one of hydrochloric acid, sulfuric acid and phosphoric acid.

[0015] Preferably, the alkaline condition is provided by sodium hydroxide and / or potassium hydroxide; and the pH of the alkaline condition is 10-12.

[0016] Preferably, the temperature for mixing and reacting the acidification-treated lignin with carbon disulfide is 20-30℃; and the reaction time is 1-5h.

[0017] Preferably, the heat treatment is carried out at 60-80℃ for 8-10h; and the heat treatment is preferably carried out under vacuum condition.

[0018] Preferably, the lignin is provided by papermaking black liquor; the papermaking black liquor is blackish-brown wastewater containing a large amount of lignin generated in the alkaline pulping process of papermaking industry; and the concentration of lignin in the papermaking black liquor is 25-35wt%.

[0019] The application also provides a preparation method of vulcanized rubber, comprising: mixing latex, alkali, rubber vulcanization accelerator, sulfur and zinc oxide, and drying at 60-150℃ to obtain vulcanized rubber.

[0020] The preparation method of the rubber vulcanization accelerator comprises:

[0021] The lignin is subjected to acidification treatment, and then the acidification-treated lignin is mixed with carbon disulfide and reacted under alkaline condition; and the product obtained by the reaction is subjected to heat treatment to obtain a rubber vulcanization accelerator.

[0022] Preferably, the mass ratio of the latex dry glue, alkali, rubber vulcanization accelerator, sulfur and zinc oxide is 100:(0.1-2):(1-5):(1-2):(0.4-0.6) by mass parts, preferably 100:0.2:(1-2):2:0.4.

[0023] Preferably, the alkali includes sodium hydroxide or potassium hydroxide; the alkali is mixed with other raw materials in the form of a solution.

[0024] The present application converts the methoxyl structure in lignin into phenolic hydroxyl structure through acidification treatment, greatly increases the content of phenolic hydroxyl structure, loads xanthate on lignin by using the reaction of phenolic hydroxyl and carbon disulfide, and obtains lignin xanthate, which has good vulcanization promotion and reinforcing effects on rubber, is an environmentally friendly new type of multifunctional rubber additive, and can be applied to the production of rubber products. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The reaction process of the lignin xanthate of the present application;

[0026] Figure 2 The infrared spectrum of the lignin xanthate prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be described in detail below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] In order to further illustrate the present application, the following examples are used for detailed description. The raw materials used in the following examples and comparative examples of the present application are all commercially available.

[0029] The papermaking black liquor used in the examples and comparative examples of the present application is provided by Hainan Jinhai Pulp Paper Co., Ltd.; carbon disulfide is purchased from Shanghai Aladdin Biochemical Co., Ltd.; sodium hydroxide, potassium hydroxide, hydrochloric acid and sulfuric acid are purchased from Xilong Scientific Co., Ltd.; sulfur dispersion, zinc oxide dispersion and zinc diethyl dithiocarbamate (ZDC) dispersion are provided by Zhejiang Tianhe Resin Co., Ltd.; concentrated natural latex is provided by Hainan Rubber Group Co., Ltd.

[0030] Example 1

[0031] The preparation method of the rubber vulcanization accelerator of the present embodiment, the reaction process is as shown in Figure 1 The specific steps include the following steps:

[0032] (1) into a 500 mL three-necked flask equipped with an electric stirrer and reflux condenser, 10 g of papermaking black liquor, 100 mL of pure water were added, and the papermaking black liquor was fully dissolved by stirring;

[0033] (2) 5 mL of hydrochloric acid was added to the system obtained in step (2) to adjust the pH of the system to 2, and the papermaking black liquor was acidified. The reaction temperature was controlled at 100°C, and the stirring was continued. After 10 hours of reaction at constant temperature, it was cooled to room temperature, 5 g of sodium hydroxide was added to adjust the pH of the system to 12, and then 5 mL of carbon disulfide was slowly added (the mass ratio of lignin to carbon disulfide was controlled at 1:1). The reaction was carried out for 2 hours, and then the product was allowed to stand and analyze. After filtration, it was washed with pure water until neutral, and then dried in a vacuum drying oven at 60°C for 8 hours to obtain lignin xanthate. The infrared analysis of lignin xanthate obtained the spectrum as shown in Figure 2 From Figure 2 it can be seen that the infrared spectrum of lignin loaded xanthate appears C=S and C-S bonds at 1365 cm -1 and 867 cm -1 , respectively, indicating that the lignin in the black liquor is successfully loaded with the accelerator xanthate after reaction.

[0034] The prepared lignin xanthate was used as a rubber vulcanization accelerator to prepare a vulcanized rubber film, which specifically included the following steps:

[0035] (1) Preparation of compounded latex film: 100 parts (by mass) of concentrated natural latex (dry rubber, i.e., 100 parts of concentrated natural latex dry rubber) was taken, and 0.2 parts of potassium hydroxide, 2.0 parts of lignin xanthate, 1.0 part of sulfur, and 0.4 part of zinc oxide were added. After stirring and mixing uniformly, a compounded latex was obtained, which was poured onto a glass plate and naturally air-dried to form a compounded latex film. Potassium hydroxide was mixed with other raw materials in the form of a solution, and the content of potassium hydroxide in the potassium hydroxide solution was 0.5 mol / L. Sulfur and zinc oxide were mixed with other raw materials in the form of water dispersion, respectively. The mass concentration of sulfur in the sulfur dispersion was 60 wt%, and the mass concentration of zinc oxide in the zinc oxide dispersion was 60 wt%; (2) Preparation of vulcanized latex film: the compounded latex film was washed in a 60°C water bath and placed in a 100°C drying oven for 2h to obtain a vulcanized rubber film.

[0036] Example 2

[0037] The preparation method of the rubber vulcanization accelerator of this embodiment includes the following steps:

[0038] (1) into a 500 mL three-necked flask equipped with an electric stirrer and reflux condenser, 10 g of papermaking black liquor, 100 mL of pure water were added, and the papermaking black liquor was fully dissolved by stirring;

[0039] (2) To the system obtained in step (2), 8 mL of hydrochloric acid was added to adjust the pH of the system to about 2, and the papermaking black liquor was subjected to acidification treatment, the reaction temperature was controlled at 100°C, and the stirring was continued. After 12 hours of reaction at constant temperature, it was cooled to room temperature, 6 g of sodium hydroxide was added to adjust the pH of the system to 12, and then 8 mL of carbon disulfide was slowly added dropwise (the mass ratio of lignin to carbon disulfide was controlled to be 1:1), and the reaction was carried out for 3 hours. After standing, the product was analyzed and separated, filtered, washed with pure water until neutral, and dried in a vacuum drying oven at 60°C for 8 hours to obtain lignin xanthate.

[0040] The prepared lignin xanthate was used as a rubber vulcanization accelerator to prepare a vulcanized rubber film, which specifically included the following steps:

[0041] (1) Preparation of compounded latex film: 100 parts (based on the mass of dry rubber) of concentrated natural latex was taken, 0.2 parts of potassium hydroxide, 1.8 parts of lignin xanthate, 1.0 part of sulfur, and 0.4 part of zinc oxide were added, and after stirring and mixing uniformly, compounded latex was obtained. Pour it on a glass plate and let it dry naturally to form a compounded latex film. Potassium hydroxide was mixed with other raw materials in the form of a solution. In the potassium hydroxide solution, the content of potassium hydroxide was 0.5 mol / L. Sulfur and zinc oxide were mixed with other raw materials in the form of water dispersion. The mass concentration of sulfur in the sulfur dispersion was 60 wt%. The mass concentration of zinc oxide in the zinc oxide dispersion was 60 wt%.

[0042] (2) Preparation of vulcanized latex film: the compounded latex film was washed in a 60°C water bath and placed in a 100°C drying oven for 2 hours to obtain a vulcanized rubber film.

[0043] Example 3

[0044] The preparation method of the rubber vulcanization accelerator of this embodiment includes the following steps:

[0045] (1) A 500 mL three-necked flask equipped with an electric stirrer and a reflux condenser was charged with 30 g of papermaking black liquor and 150 mL of pure water, and the papermaking black liquor was stirred to dissolve completely.

[0046] (2) To the system obtained in step (2), 10 mL of hydrochloric acid was added to adjust the pH of the system to 2, and the papermaking black liquor was subjected to acidification treatment, the reaction temperature was controlled at 85°C, and the stirring was continued. After 18 hours of reaction at constant temperature, it was cooled to room temperature, 8 g of sodium hydroxide was added to adjust the pH of the system to 12, and then 8 mL of carbon disulfide was slowly added dropwise (the mass ratio of lignin to carbon disulfide was controlled to be 1:1), and the reaction was carried out for 4 hours. After standing, the product was analyzed and separated, filtered, washed with pure water until neutral, and dried in a vacuum drying oven at 60°C for 8 hours to obtain lignin xanthate.

[0047] The prepared lignin xanthate is used as a rubber vulcanization accelerator to prepare a vulcanized rubber film, specifically including the following steps:

[0048] (1) Preparation of a compounded latex film: 100 parts of concentrated natural latex, based on the mass of dry rubber, is taken, and 0.2 parts of potassium hydroxide, 1.6 parts of lignin xanthate, 1.0 parts of sulfur, and 0.4 parts of zinc oxide are added, and the mixture is stirred and uniformly mixed to obtain a compounded latex, which is poured onto a glass plate and naturally air-dried to form a compounded latex film; the potassium hydroxide is mixed with other raw materials in the form of a solution, and the content of potassium hydroxide in the potassium hydroxide solution is 0.5 mol / L; the sulfur and zinc oxide are mixed with other raw materials in the form of aqueous dispersions; the mass concentration of sulfur in the sulfur dispersion is 60 wt%; the mass concentration of zinc oxide in the zinc oxide dispersion is 60 wt%;

[0049] (2) Preparation of a vulcanized latex film: the compounded latex film is washed in a 60°C water bath and placed in a 100°C drying oven for 2 hours to obtain a vulcanized rubber film.

[0050] Example 4

[0051] The preparation method of the rubber vulcanization accelerator of the present embodiment includes the following steps:

[0052] (1) A 500 mL three-necked flask equipped with an electric stirrer and a reflux condenser is charged with 40 g of papermaking black liquor and 150 mL of pure water, and the papermaking black liquor is stirred to dissolve completely;

[0053] (2) 12 mL of hydrochloric acid is added to the system obtained in step (2) to adjust the pH of the system to 2, and the papermaking black liquor is subjected to acidification treatment, and the reaction temperature is controlled at 80°C, and the stirring is continued, and after 24 hours of reaction at constant temperature, the system is cooled to room temperature, 10 g of sodium hydroxide is added to adjust the pH of the system to 12, and then 10 mL of carbon disulfide is slowly added dropwise (the mass ratio of lignin to carbon disulfide is controlled to be 1:1), and the reaction is carried out for 4 hours, and the product is allowed to settle, and the product is filtered, washed with pure water until neutral, and dried in a 60°C vacuum drying oven for 8 hours to obtain lignin xanthate.

[0054] The prepared lignin xanthate is used as a rubber vulcanization accelerator to prepare a vulcanized rubber film, specifically including the following steps:

[0055] (1) Preparation of the compounded latex film: 100 parts of concentrated natural latex, based on the mass of dry rubber, was added with 0.2 parts of potassium hydroxide, 1.5 parts of lignin xanthate, 1.0 part of sulfur and 0.4 part of zinc oxide, stirred and mixed uniformly to obtain the compounded latex, which was then poured onto a glass plate and naturally air-dried to form the compounded latex film; the potassium hydroxide was mixed with other raw materials in the form of a solution, and the content of potassium hydroxide in the potassium hydroxide solution was 0.5 mol / L; the sulfur and zinc oxide were mixed with other raw materials in the form of water dispersions respectively; the mass concentration of sulfur in the sulfur dispersion was 60 wt%; the mass concentration of zinc oxide in the zinc oxide dispersion was 60 wt%;

[0056] (2) Preparation of the vulcanized latex film: the compounded latex film was washed in a 60°C water bath and then placed in a 100°C drying oven for vulcanization for 2 hours to obtain the vulcanized rubber film.

[0057] Example 5

[0058] The preparation method of the rubber vulcanization accelerator of the present example comprises the following steps:

[0059] (1) A 500 mL three-necked flask equipped with an electric stirrer and a reflux condenser was charged with 40 g of papermaking black liquor and 200 mL of pure water, and the papermaking black liquor was stirred to be fully dissolved;

[0060] (2) 15 mL of hydrochloric acid was added to the system obtained in step (2) to adjust the pH of the system to 2, and the papermaking black liquor was subjected to acidification treatment, the reaction temperature was controlled at 75°C, and the stirring was continued. After reaction at constant temperature for 48 hours, the system was cooled to room temperature, 15 g of sodium hydroxide was added to adjust the pH of the system to 12, and then 15 mL of carbon disulfide was slowly added dropwise (the mass ratio of lignin to carbon disulfide was controlled to be 1:1), and the reaction was carried out for 5 hours. After standing, the product was analyzed and discharged, filtered, washed with pure water until neutral, and dried in a 60°C vacuum drying oven for 8 hours to obtain lignin xanthate.

[0061] The prepared lignin xanthate was used as a rubber vulcanization accelerator to prepare a vulcanized rubber film, which specifically comprises the following steps:

[0062] (1) Preparation of the compounded latex film: 100 parts of concentrated natural latex, based on the mass of dry rubber, was added with 0.2 parts of potassium hydroxide, 1.5 parts of lignin xanthate, 1.0 part of sulfur and 0.4 part of zinc oxide, stirred and mixed uniformly to obtain the compounded latex, which was then poured onto a glass plate and naturally air-dried to form the compounded latex film; the potassium hydroxide was mixed with other raw materials in the form of a solution, and the content of potassium hydroxide in the potassium hydroxide solution was 0.5 mol / L; the sulfur and zinc oxide were mixed with other raw materials in the form of water dispersions respectively; the mass concentration of sulfur in the sulfur dispersion was 60 wt%; the mass concentration of zinc oxide in the zinc oxide dispersion was 60 wt%;

[0063] (2) The compounded latex film was washed in a 60°C water bath and placed in a 100°C drying oven for 2h to obtain a vulcanized film.

[0064] Example 6

[0065] The difference between this example and Example 1 is that in this example, the concentrated natural latex is replaced by a 60% solid content styrene-butadiene latex, and the dry rubber mass of the styrene-butadiene latex is the same as that of the concentrated natural latex; the use amount of the remaining raw materials is adjusted accordingly according to the dry rubber mass of the styrene-butadiene latex; and the step of preparing the vulcanized film is performed with reference to that in Example 1.

[0066] Comparative Example 1

[0067] The difference between this comparative example and Example 1 is that in this comparative example, the commercially available rubber vulcanization accelerator ZDC is used to replace the lignin xanthate, and the step of preparing the vulcanized film is performed with reference to that in Example 1.

[0068] Comparative Example 2

[0069] The difference between this comparative example and Example 1 is that in this comparative example, 2.0 parts of lignin xanthate is replaced by 2.0 parts of lignin, and the step of preparing the vulcanized film is performed with reference to that in Example 1.

[0070] Comparative Example 3

[0071] The difference between this comparative example and Example 1 is that in this comparative example, 2.0 parts of lignin xanthate is replaced by 5.0 parts of lignin xanthate, and the step of preparing the vulcanized film is performed with reference to that in Example 1.

[0072] Test Example

[0073] The samples obtained in the examples and comparative examples of the present application were subjected to performance test analysis, and the detection indexes and methods are shown as follows:

[0074] Vulcanization characteristics of the compounded film: The determination of the vulcanization characteristics of the compounded latex film was performed according to GB / T 9869-2014 Rubber Compounds - Determination of Vulcanization Characteristics - Disc Rotational Oscillation Curemeter Method.

[0075] Tensile strength of the vulcanized film: The tensile strength of the vulcanized film was tested according to GB / T 528-2009 Rubber, Vulcanized or Thermoplastic - Determination of Tensile Stress-Strain Properties.

[0076] Tear strength of the vulcanized film: The tear strength of the vulcanized film was tested according to GB / T 529-2008 Rubber, Vulcanized or Thermoplastic - Determination of Tear Strength (Pants Test).

[0077] The test results are shown in Table 1.

[0078] Table 1

[0079]

[0080] As can be seen from Table 1, compared with the comparative examples, the vulcanized rubber film prepared by using the lignin xanthate prepared by the embodiment of the present application as a rubber vulcanization accelerator has higher tensile strength and tear strength.

[0081] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. Use of a rubber vulcanization accelerator for improving the tensile strength and tear strength of rubber, characterized in that, The preparation method of the rubber vulcanization accelerator comprises: acidizing lignin, and then mixing and reacting the acidized lignin with carbon disulfide under alkaline conditions; and performing heat treatment on the product obtained in the reaction to obtain the rubber vulcanization accelerator; the mass ratio of the lignin to the carbon disulfide is 1:(0.5-2.0); the acidizing treatment comprises: mixing the lignin with water, adjusting the pH to 2 with an acid, and then reacting at 60-100 ℃ for 2-50 h; the heat treatment is performed at 60-80 ℃ for 8-10 h; the rubber vulcanization accelerator is added in the rubber in an amount of 1-2 wt%.

2. Use according to claim 1, characterized in that, the pH of the alkaline conditions is 10-12.

3. Use according to claim 1, characterized in that, when the acidized lignin is mixed with the carbon disulfide for reaction, the temperature of the reaction is 20-30 ℃.

4. Use according to claim 1, characterized in that, when the acidized lignin is mixed with the carbon disulfide for reaction, the time of the reaction is 1-5 h.

5. A method for producing a vulcanized rubber, characterized by, comprises: mixing latex, alkali, rubber vulcanization accelerator, sulfur and zinc oxide, and drying at 60-150 ℃ to obtain vulcanized rubber; the preparation method of the rubber vulcanization accelerator comprises: acidizing lignin, and then mixing and reacting the acidized lignin with carbon disulfide under alkaline conditions; and performing heat treatment on the product obtained in the reaction to obtain the rubber vulcanization accelerator; the mass ratio of the lignin to the carbon disulfide is 1:(0.5-2.0); the acidizing treatment comprises: mixing the lignin with water, adjusting the pH to 2 with an acid, and then reacting at 60-100 ℃ for 2-50 h; the heat treatment is performed at 60-80 ℃ for 8-10 h; in mass parts, the mass ratio of the latex, alkali, rubber vulcanization accelerator, sulfur and zinc oxide is 100:(0.1-2):(1-2):(1-2):(0.4-0.6).

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