阅读说明：本技术 一种提高湿法混炼胶中白炭黑与橡胶胶乳相容性的方法 (Method for improving compatibility of white carbon black and rubber latex in wet-process rubber compound ) 是由 陶再山 李春华 于 2019-11-08 设计创作，主要内容包括：本发明公开了一种提高湿法混炼胶中白炭黑与橡胶胶乳相容性的方法,其特征在于,它包括如下步骤：将白炭黑和双-(3-丙基三乙氧基硅烷)多硫化物以重量比50：50混匀,制得预分散母料；将预分散母料和白炭黑加入到橡胶胶乳中,混匀；其中,预分散母料、白炭黑和橡胶乳胶(以干胶计)的重量比为5～10：50：100。本发明采用双-(3-丙基三乙氧基硅烷)多硫化物和白炭黑混匀为预分散母料,再与白炭黑一起加到胶乳中,经过了双-(3-丙基三乙氧基硅烷)多硫化物改性的白炭黑同时具有亲水亲油的双亲特性,阻止了白炭黑的团聚倾向,提高了白炭黑与橡胶胶乳的相容性,改善了白炭黑在胶乳中的分散性。(The invention discloses a method for improving the compatibility of white carbon black and rubber latex in wet-process rubber compound, which is characterized by comprising the following steps: white carbon black and bis- (3-propyltriethoxysilane) polysulfide in a weight ratio of 50: 50, uniformly mixing to prepare a pre-dispersion master batch; adding the pre-dispersed master batch and the white carbon black into the rubber latex, and uniformly mixing; wherein the weight ratio of the pre-dispersed master batch to the white carbon black to the rubber latex (calculated by dry rubber) is 5-10: 50: 100. the invention adopts the evenly mixed di- (3-propyltriethoxysilane) polysulfide and white carbon black as the pre-dispersion master batch, and then the pre-dispersion master batch and the white carbon black are added into the latex together, and the white carbon black modified by the di- (3-propyltriethoxysilane) polysulfide has hydrophilic and oleophilic amphiphilic characteristics, thereby preventing the agglomeration tendency of the white carbon black, improving the compatibility of the white carbon black and the rubber latex and improving the dispersibility of the white carbon black in the latex.)

1. A method for improving the compatibility of white carbon black and rubber latex in wet-process rubber compound is characterized in that the method is to uniformly mix the white carbon black and bis- (3-propyltriethoxysilane) polysulfide into pre-dispersion master batch.

2. The method for improving the compatibility of white carbon black and rubber latex in the wet rubber compound as claimed in claim 1, characterized by comprising the following steps:

i) white carbon black and bis- (3-propyltriethoxysilane) polysulfide in a weight ratio of 50: 50, uniformly mixing to prepare a pre-dispersion master batch;

ii) adding the pre-dispersed master batch and the white carbon black into the rubber latex, and uniformly mixing to obtain a white carbon black-rubber latex mixture; wherein the weight ratio of the pre-dispersed master batch to the white carbon black to the rubber latex (calculated by dry rubber) is 5-10: 50: 100.

3. the method for improving the compatibility of the white carbon black and the rubber latex in the wet-process rubber compound as claimed in claim 2, wherein the solid content of the rubber latex is 10% -40%.

4. A method as claimed in claim 1 or 2, wherein the average sulphur chain length of the bis- (3-propyltriethoxysilane) polysulphide is in the range 3.55 < SMELM < 3.65.

5. A method of improving the compatibility of silica with rubber latex in a wet mix as claimed in claim 1 or 2 wherein the average sulfur chain length of bis- (3-propyltriethoxysilane) polysulphide is in the range 2.00 < SMELM < 2.15.

6. The method for improving the compatibility of the white carbon black and the rubber latex in the wet-process rubber compound as claimed in claim 1 or 2, wherein the method for preparing the pre-dispersed master batch is that the white carbon black is added into a high-speed stirrer, and then the bis- (3-propyltriethoxysilane) polysulfide is added into the stirrer in a spraying manner and is uniformly mixed with the white carbon black to obtain the pre-dispersed master batch.

7. The method for improving the compatibility of the white carbon black and the rubber latex in the wet-process rubber compound according to claim 1 or 2, characterized in that the pre-dispersed master batch further contains a titanate coupling agent and n-propyltriethoxysilane.

8. The method for improving the compatibility of the white carbon black and the rubber latex in the wet-process rubber compound as claimed in claim 8, wherein the weight ratio of the titanate coupling agent, the n-propyltriethoxysilane, the bis- (3-propyltriethoxysilane) polysulfide and the white carbon black in the pre-dispersion master batch is 2-3: 20-30: 20-50: 50.

9. the method for improving the compatibility of white carbon black and rubber latex in the wet mix as claimed in, wherein the titanate coupling agent is at least one of tetraisopropyl titanate and di (triethanolamine) diisopropyl titanate.

10. The method for improving the compatibility of the white carbon black and the rubber latex in the wet-process rubber compound as claimed in claim 7, wherein the mixing sequence for preparing the pre-dispersed master batch is as follows: the titanate coupling agent and n-propyl triethoxysilane are mixed evenly, then the titanate coupling agent and bis- (3-propyl triethoxysilane) polysulfide are mixed evenly, and the mixture is added into white carbon black to prepare pre-dispersion master batch.

Technical Field

The application relates to a method for improving the compatibility of white carbon black and rubber latex in wet-process rubber compound, belonging to the technical field of chemical industry.

Background

Rubber mixing is a bottleneck of rubber processing technology and is a key to the performance of rubber products. The energy consumption of the rubber mixing process is huge and accounts for almost 40% of the total energy consumption of rubber product production, so in recent years, great attention is paid to technical innovation of the rubber mixing process, wherein the wet mixing rubber process technology is the focus of recent research.

The wet rubber mixing process is to prepare water dispersion with carbon black, white carbon black and other stuffing, mix the water dispersion with rubber latex in liquid state, coagulate, dewater, dry and other steps to produce rubber compound. The technical difficulty is that the white carbon black aqueous dispersion is incompatible with rubber latex, white carbon black is difficult to coprecipitate with the latex, and the white carbon black is unevenly dispersed in the latex, so that the white carbon black filling amount of the rubber compound is large in fluctuation and poor in dispersion uniformity, so that the rubber compound cannot have good performance, and the wet-method rubber mixing process is difficult to popularize and apply in large industry.

In the existing wet mixing process, other surface modifiers are adopted to only solve the problem of white carbon black surface modification, but cannot be chemically reacted and bonded with latex, so that the further application of rubber mixtures is influenced, and the method is provided for improving the compatibility of white carbon black and rubber latex.

Disclosure of Invention

The technical problem is as follows: the technical problems to be solved by the invention are the compatibility problem and the dispersion uniformity problem of the white carbon black and the rubber latex in the wet mixing rubber process, so that the technical problems of the wet mixing rubber process are solved, and the co-precipitation of the white carbon black and the rubber latex is improved.

The technical scheme is as follows: in order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a method for improving the compatibility of white carbon black and rubber latex in wet-process rubber compound, which is characterized in that the method takes the mixed mixing of the white carbon black and bis- (3-propyltriethoxysilane) polysulfide as pre-dispersed master batch.

Preferably, it comprises the following steps:

i) white carbon black and bis- (3-propyltriethoxysilane) polysulfide in a weight ratio of 50: 50, uniformly mixing to prepare a pre-dispersion master batch;

ii) adding the pre-dispersed master batch and the white carbon black into the rubber latex, and uniformly mixing; wherein the weight ratio of the pre-dispersed master batch to the white carbon black to the rubber latex (calculated by dry rubber) is 5-10: 50: 100. .

Further, the solid content of the rubber latex is 10 to 40 percent.

Preferably, the rubber latex has a solids content of 20%. The dispersion of rubber latex and white carbon black is facilitated, the solid-liquid suspension state of the mixed solution is ensured, and preferably, the solid content of the rubber latex is 20%.

Generally, the white carbon black is precipitated white carbon black, and the water content is 4-10%.

In the method, white carbon black and bis- (3-propyltriethoxysilane) polysulfide in a weight ratio of 50: 50, and uniformly mixing to obtain the pre-dispersed master batch, namely adding the white carbon black into a high-speed stirrer, and then adding the bis- (3-propyltriethoxysilane) polysulfide into the stirrer in a spraying manner to uniformly mix with the white carbon black to obtain the pre-dispersed master batch. In the process, the bis- (3-propyltriethoxysilane) polysulfide is hydrolyzed by water brought by the white carbon black raw material, the ethoxylation is removed, and the polysulfide is hydrolyzed into silicon hydroxyl, and then the silicon hydroxyl and the silicon hydroxyl of the white carbon black are subjected to condensation reaction, so that the white carbon black is grafted with organic oleophilic groups, and the compatibility of the white carbon black and rubber latex is improved; in addition, the bis- (3-propyltriethoxysilane) polysulfide which does not react completely is loaded on the surface of the white carbon black particles, so that the secondary agglomeration of the white carbon black is prevented, and the aim of self-dispersion of the bis- (3-propyltriethoxysilane) polysulfide is fulfilled.

And then adding the pre-dispersion body and the white carbon black into the rubber latex, wherein bis- (3-propyltriethoxysilane) polysulfide in the pre-dispersion body reacts with the white carbon black and the rubber latex, so that a bridge is built between the white carbon black and the rubber latex, the white carbon black has hydrophilic and oleophilic amphiphilic characteristics and is uniformly dispersed in the rubber latex, the aim of coprecipitation with the rubber latex is fulfilled, and the problems of large fluctuation of the white carbon black filling amount and non-uniform sizing material of wet-process rubber mixing are solved.

Through a large number of experimental researches of the inventor, the n-propyltriethoxysilane serving as a byproduct of bis- (3-propyltriethoxysilane) polysulfide is also added into the pre-dispersion master batch, and the titanate coupling agent is added to promote the reaction of the bis- (3-propyltriethoxysilane) polysulfide and the n-propyltriethoxysilane with the white carbon black and the rubber latex, so that the pre-dispersion master batch is more favorably dispersed, especially a mixture obtained after the pre-dispersion master batch, the white carbon black and the rubber latex are mixed is uniform, the white carbon black is fully and uniformly dispersed in the mixture without agglomeration, and the coprecipitation property of the white carbon black and the rubber latex is greatly improved.

Wherein, the addition amount of the titanate coupling agent and the n-propyltriethoxysilane is required to be proper. Excessive titanate coupling agent can be hydrolyzed in latex, not only can not play a promoting role, but also can cause the waste of raw materials, and too little titanate coupling agent can not enable the propyl triethoxy silane to fully react, thereby influencing the effect. The organic group of the n-propyltriethoxysilane is n-propyl, which is not suitable for generating chemical bonds with rubber latex, but the addition of the n-propyltriethoxysilane is beneficial to the dispersion of the white carbon black, so the addition of the n-propyltriethoxysilane needs to be suitable, which can ensure the sufficient dispersion of the white carbon black without agglomeration and cannot influence the combination of the white carbon black and the rubber latex through the chemical bonds of bis- (3-propyltriethoxysilane) polysulfide. Proved by multiple times of verification of the experimenter, the titanate coupling agent, the n-propyltriethoxysilane and the bis- (3-propyltriethoxysilane) polysulfide are mixed according to the weight ratio of (2-3): 20-30: 20-50 of the white carbon black is added to prepare a pre-dispersion master batch, and the white carbon black has better dispersibility. Preferably, the weight ratio of the titanate coupling agent, the n-propyltriethoxysilane to the bis- (3-propyltriethoxysilane) polysulfide is 2-3: 20-30: 20 to 50.

Furthermore, the titanate coupling agent is at least one of tetraisopropyl titanate, di (triethanolamine) diisopropyl titanate or a mixture of the tetraisopropyl titanate and the di (triethanolamine) diisopropyl titanate, and experiments prove that the tetraisopropyl titanate or the di (triethanolamine) diisopropyl titanate has the best catalytic reaction effect on the n-propyltriethoxysilane and the bis- (3-propyltriethoxysilane) polysulfide.

The titanate coupling agent, the n-propyltriethoxysilane and the bis- (3-propyltriethoxysilane) polysulfide can be mixed in proportion and then added into the white carbon black to prepare the pre-dispersion master batch, and also can be respectively added into the white carbon black to prepare the pre-dispersion master batch. Preferably, the titanate coupling agent and the n-propyltriethoxysilane are uniformly mixed, then the titanate coupling agent and the bis- (3-propyltriethoxysilane) polysulfide are uniformly mixed, and the mixture is added into the white carbon black to prepare the pre-dispersion master batch.

The white carbon black-rubber composite material prepared by adopting bis- (3-propyltriethoxysilane) polysulfide modified white carbon black to react with white carbon black and rubber latex can be used for rubber products prepared by a sulfur vulcanized rubber system, such as tires, rubber rollers and other products. The commercially available bis- (3-propyltriethoxysilane) polysulfides can be used. It has been found that bis- (3-propyltriethoxysilane) polysulfides of different average sulfur chain lengths can be used for different wet compounded rubber formulations.

The product with the average sulfur chain length of 3.55-3.90 is preferably selected from bis- (3-propyltriethoxysilane) polysulfide with the average sulfur chain length range of 3.55 < SAM < 3.65, so that the subsequent low-temperature mixing is facilitated, the sulfur chain breakage and free sulfur precipitation caused by high temperature are reduced, the rubber material is vulcanized in advance, and the performance of subsequent rubber compound such as scorch is influenced.

For the product with the average sulfur chain length of 2.00-2.50 specifications, preferably, the product with the average sulfur chain length of bis- (3-propyltriethoxysilane) polysulfide of 2.00 & lt S average & lt 2.15 is selected, and the product with the average sulfur chain length of 2.00 & lt S average & lt 2.15 is more beneficial to subsequent high-temperature mixing, and the mechanical strength and the weather resistance of subsequent rubber compound are improved.

Has the advantages that: compared with the prior art, the invention has the beneficial effects that:

1. the invention adopts the bis- (3-propyltriethoxysilane) polysulfide and the white carbon black to be uniformly mixed to be the pre-dispersion master batch, and then the pre-dispersion master batch and the white carbon black are added into the latex together, the white carbon black modified by the bis- (3-propyltriethoxysilane) polysulfide has hydrophilic and oleophilic amphiphilic characteristics, the agglomeration tendency of the white carbon black is prevented, the compatibility of the white carbon black and the rubber latex is improved, the dispersibility of the white carbon black in the latex is improved, and the composite material with better performance is finally obtained. The silane coupling agent is consistent with the silane coupling agent in the prior dry mixing rubber, can be applied to the prior mainstream sulfur vulcanized rubber system to prepare rubber products such as tires, rubber rollers and the like, and expands the application prospect of the wet mixing rubber.

2. In the existing wet mixing, the white carbon black aqueous dispersion is mixed with rubber latex in a liquid state, the physical properties of the white carbon black and the rubber latex determine that the white carbon black is hydrophilic, the liquid latex is oleophilic, the white carbon black and the rubber latex are difficult to be uniformly mixed and coprecipitated, and the bis- (3-propyltriethoxysilane) polysulfide is easy to hydrolyze in the white carbon black aqueous dispersion and then monomer polymerization occurs, so that the invention fails, and the invention mixes the bis- (3-propyltriethoxysilane) polysulfide and the white carbon black by the ratio of 50: 50, the white carbon black is modified to enable the white carbon black to have hydrophilic and oleophilic amphiphilic characteristics, and the purpose of dispersing white carbon black particles is achieved, so that the compatibility of the white carbon black and rubber latex is improved, and the problem of co-precipitation is solved.

3. The invention relates to a method for preparing a rubber latex, which comprises the following steps of (by dry rubber) mixing 5-10 parts of pre-dispersed master batch, white carbon black and rubber latex: 50: 100. the proportion of the white carbon black and the rubber latex are uniformly mixed, and the pre-dispersed master batch is used as a modifier, so that the problem of compatibility of the white carbon black and the rubber latex is solved, the problems that in the prior art, bis- (3-propyltriethoxysilane) polysulfide is directly added into a rubber latex aqueous solution, the bis- (3-propyltriethoxysilane) polysulfide is incompatible with the rubber latex, the dispersion is not uniform, the risk of hydrolytic failure is caused, and the problem that bis- (3-propyltriethoxysilane) polysulfide is compatible with the rubber latex is solved, the risk of hydrolytic failure of the bis- (3-propyltriethoxysilane) polysulfide in the rubber latex aqueous solution is avoided, and the using amount of the bis- (3-propyltriethoxysilane) polysulfide is not increased.

4. According to the method, the titanate coupling agent and the n-propyltriethoxysilane are added into the pre-dispersion master batch, so that the problem of selling the n-propyltriethoxysilane serving as a byproduct of bis- (3-propyltriethoxysilane) polysulfide is solved, the problem that the n-propyltriethoxysilane is not suitable for chemical reaction with rubber latex is solved, and the addition of the n-propyltriethoxysilane is more beneficial to the dispersion of white carbon black.

5. According to the method, the titanate coupling agent is added into the pre-dispersion master batch, so that the reaction of n-propyltriethoxysilane and bis- (3-propyltriethoxysilane) polysulfide is promoted, the reaction of n-propyltriethoxysilane and bis- (3-propyltriethoxysilane) polysulfide and white carbon black is promoted, the n-propyltriethoxysilane and bis- (3-propyltriethoxysilane) polysulfide can be more favorably brought into play to the effect that a 'molecular bridge' is built between white carbon black and rubber latex to play a role of the coupling agent, and the physicochemical properties of subsequent rubber compound can be favorably improved.

6. The method improves the compatibility of the white carbon black and the rubber latex in the wet-process rubber compound, improves the compatibility of the bis- (3-propyltriethoxysilane) polysulfide and the latex, and improves the dispersibility of the white carbon black in the rubber latex, thereby optimizing the coprecipitation of the white carbon black and the rubber latex and stabilizing the filling amount and the sizing material uniformity of the white carbon black in the wet-process rubber compound.

Detailed Description

The present invention is illustrated in greater detail by the following examples, which are not intended to be limiting in any way, and any person skilled in the art may, by means of the teachings disclosed below, modify or modify the equivalent embodiments with equivalent variations. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.

Example 1:

raw materials: (1) bis- (3-propyltriethoxysilane) polysulfides: an average sulfur chain length of 3.60; (2) precipitation method white carbon black: the water content is 8%; (3) natural rubber latex: the solid content was 20%.

Preparing a pre-dispersed master batch: adding 10Kg of white carbon black into a 50L high-speed mixer at one time, covering a cover, opening an exhaust port, then opening and stirring, spraying 10Kg of bis- (3-propyltriethoxysilane) polysulfide through a spraying port, and continuing stirring for 2min after spraying for 10min to obtain the pre-dispersion master batch.

Preparing a white carbon black-rubber latex mixture: 100g of pre-dispersed master batch and 500g of white carbon black are respectively added into 5000g of natural rubber latex and uniformly mixed to obtain a white carbon black-rubber latex mixture.

Example 2:

raw materials: (1) bis- (3-propyltriethoxysilane) polysulfides: an average sulfur chain length of 2.05; (2) precipitation method white carbon black: the water content is 8%; (3) natural rubber latex: the solid content was 20%.

Preparing a pre-dispersed master batch: adding 10Kg of white carbon black into a 50L high-speed mixer at one time, covering a cover, opening an exhaust port, then opening and stirring, spraying 10Kg of bis- (3-propyltriethoxysilane) polysulfide through a spraying port, and continuing stirring for 2min after spraying for 10min to obtain the pre-dispersion master batch.

Preparing a white carbon black-rubber latex mixture: 80g of pre-dispersed master batch and 500g of white carbon black are respectively added into 5000g of natural rubber latex and uniformly mixed to obtain a white carbon black-rubber latex mixture.

Example 3:

raw materials: (1) bis- (3-propyltriethoxysilane) polysulfides: an average sulfur chain length of 3.62; (2) n-propyltriethoxysilane: the content is 99 percent; (3) di (triethanolamine) diisopropyl titanate: pure products; (4) precipitation method white carbon black: the water content is 8%; (5) natural rubber latex: the solid content was 20%.

Preparing a pre-dispersed master batch: di (triethanolamine) diisopropyl titanate: n-propyltriethoxysilane: bis- (3-propyltriethoxysilane) polysulfide was mixed at a weight ratio of 2.5:20:30, and di (triethanolamino) diisopropyl titanate was added to n-propyltriethoxysilane first and mixed, and then added to bis- (3-propyltriethoxysilane) polysulfide to obtain a mixed solution.

And adding 10Kg of white carbon black into a 50L high-speed mixer at one time, covering a cover, opening an exhaust port, then opening and stirring, spraying 10Kg of mixed solution through a spraying port, finishing spraying for 10min, and continuously stirring for 2min to obtain the pre-dispersed master batch.

Preparing a white carbon black-rubber latex mixture: 100g of pre-dispersed master batch and 500g of white carbon black are added into 5000g of natural rubber latex to obtain a white carbon black-rubber latex mixture.

Comparative example 1:

raw materials: (1) bis- (3-propyltriethoxysilane) polysulfides: an average sulfur chain length of 2.05; (2) precipitation method white carbon black: the water content is 8%; (3) natural rubber latex: the solid content was 20%.

Preparing a white carbon black-rubber latex mixture: 50g of bis- (3-propyltriethoxysilane) polysulfide and 500g of white carbon black are added into 5000g of natural rubber latex and mixed uniformly.

Comparative example 2:

raw materials: (1) propyltriethoxysilane: the content is 99 percent; (2) precipitation method white carbon black: the water content is 8%; (3) natural rubber latex: the solid content was 20%.

Preparing a white carbon black-rubber latex mixture: 50g of propyl triethoxysilane and 500g of white carbon black are added into 5000g of natural rubber latex and uniformly mixed.

Comparative example 3:

raw materials: (1) bis- (3-propyltriethoxysilane) polysulfides: an average sulfur chain length of 2.05; (2) white carbon black aqueous solution slurry: the content is 25 percent; (3) natural rubber latex: the solid content was 20%.

Preparing a white carbon black-rubber latex mixture: 50g of bis- (3-propyltriethoxysilane) polysulfide and 2000g of white carbon black aqueous solution slurry (25% content) 5000g of natural rubber latex are uniformly mixed.

The white carbon black-rubber latex mixtures obtained in the above examples 1 to 2 and comparative examples 1 to 3 were subjected to flocculation and drying in sequence to obtain a coprecipitated rubber compound. The mix was then cut and the freshly exposed surface observed for magnification. Referring to the GB/T6030 method for evaluating the dispersion of carbon black and carbon black/silicon dioxide in rubber, the dispersion level of the white carbon black on the exposed surface of the rubber compound is visually observed, and the visual result is that:

table 1: visual inspection dispersion grade and corresponding dispersion quality level of white carbon black

Examples	Level of dispersion quality	Visual Dispersion Scale
			Example 1	Can accept	7
Example 2	Can accept	7
			Example 3	Good taste	8
Comparative example 1	Is very poor	1～2
			Comparative example 2	Is very poor	1～2
Comparative example 3	Is very poor	1～2

The performance indexes of the product of the invention can be obtained through the table: the visual dispersion grade of the white carbon black reaches more than 7 grades, the grade 1-2 in the prior art is increased to more than 7 grades, compared with a mode of directly mixing bis- (3-propyltriethoxysilane) polysulfide or n-propyltriethoxysilane, the white carbon black and natural rubber latex together, and a mode of directly mixing bis- (3-propyltriethoxysilane) polysulfide or propyltriethoxysilane, white carbon black aqueous solution slurry and natural rubber latex together, the bis- (3-propyltriethoxysilane) polysulfide is added into the white carbon black to prepare a pre-dispersion master batch, and then the pre-dispersion master batch is mixed with the white carbon black and the natural rubber latex, so that the white carbon black is dispersed more uniformly. Particularly, when the n-propyltriethoxysilane and the titanate coupling agent are added into the pre-dispersion master batch, the white carbon black in the prepared coprecipitation rubber compound is best dispersed. The method improves the compatibility of the white carbon black and the rubber latex in the wet-process rubber compound, improves the compatibility of the bis- (3-propyltriethoxysilane) polysulfide and the rubber latex, and improves the dispersibility of the white carbon black in the rubber latex, thereby optimizing the coprecipitation of the white carbon black and the rubber latex, and stabilizing the filling amount of the white carbon black and the sizing material uniformity in the wet-process rubber compound.