CN113929991B - Scorch-resistant CR unvulcanized rubber stored at room temperature for long time, preparation method thereof and preparation method of scorch inhibitor - Google Patents

Abstract

Scorch-resistant CR unvulcanized rubber which is stored for a long time at room temperature and is scorch-resistant, a preparation method thereof and a preparation method of a scorch inhibitor are provided, and the materials comprise: raw rubber, reinforcing filler, plasticizer, vulcanization accelerator, coupling agent, anti-aging agent, scorch retarder, active agent and processing aid, when unvulcanized rubber is prepared, the materials are firstly prepared into prefabricated rubber sheets; then adding the prefabricated film into an internal mixer or an open mill, adding an active agent, a reinforcing filler, a plasticizer, a coupling agent, a scorch retarder, other processing aids and the like, and discharging rubber after mixing at a low temperature to prepare a section of rubber compound; finally, after the first section of rubber compound is placed and cooled, adding a vulcanization accelerator and an anti-aging agent into an open mill for mixing, fully opening cooling water during open mill, reducing Wen Baotong, uniformly mixing, and then discharging to obtain the final mixed compound. The invention can produce sizing material with excellent scorch safety and long-time storage through various improvements.

Description

Scorch-resistant CR unvulcanized rubber stored at room temperature for long time, preparation method thereof and preparation method of scorch inhibitor

Technical Field

The invention relates to CR unvulcanized rubber and a preparation method thereof, in particular to CR unvulcanized rubber which is scorch-resistant and can be stored at room temperature for a long time and a preparation method thereof.

Background

The neoprene is a high molecular elastomer polymerized by 2-chloro-1, 3 butadiene, is one of the main varieties of synthetic rubber, and is also a synthetic rubber with earlier development. As a general special rubber, the rubber has excellent heat resistance, weather resistance, oil resistance, flame retardance, flexural fatigue resistance, chemical corrosion resistance and the like in addition to good physical properties of the general rubber, and is widely applied to manufacturing of rubber pipes, adhesive tapes, wires and cables, adhesives, printing rubber rolls, bridge supports, coatings, flame-retardant conveying belts, air ducts, corrosion-resistant liners and the like.

Although the neoprene has excellent comprehensive performance and is widely applied to a plurality of products, the allyl chloride atom connected with the neoprene 1,2 structure is very active and is easy to react with other atoms and the like to form an irreversible cross-linked network structure, and CR heat generation amount is more in the processing process, is sensitive to temperature and is easy to scorch, so that the mobility of the sizing material is poor, the scorching time is shortened, the pressed sizing blank is rough, the self-adhesion is reduced, the quality problems of defective sizing, rounded corners, sulfur marks, bubbles, bulges and the like of the products are caused, and the processability is lost in severe cases. Although reasonable storage conditions and processing procedures can avoid CR scorching during storage and processing, neoprene compounds (unvulcanized rubber) are more difficult to store for extended periods of time at room temperature, typically not exceeding 30 days. In addition, certain special industries, rubber compound take-out and processing services have higher and higher requirements on the storage period of the CR unvulcanized rubber, and how to improve the storage period of the CR unvulcanized rubber has become an important subject.

The invention patent application with the application number of CN2015199936. X and the name of a process method for improving the scorching performance of chloroprene rubber discloses a process method for improving the scorching performance of CR rubber compound, wherein the process is to add the formula components which have no influence on the scorching time into CR to mix into master batch, and then add the rest small material components when producing the rubber compound, thereby achieving the purpose of improving the scorching performance of the chloroprene rubber compound. However, this method is not suitable for final rubber mixing, has obvious limitations, and is not suitable for manufacturers without rubber mixing equipment to uniformly add the residual small materials, and is also not suitable for products which need to be prepared into semi-finished products (such as rubberized fabrics, films and the like) and stored for a long time.

The patent application CN201310661911.4 entitled "Stable neoprene", discloses a neoprene compound with a certain stability that avoids the problem of decomposition due to CR instability in a short time, thereby avoiding waste, but does not relate to the scorch resistance of the neoprene compound, and the CR compound can be stored for a long period of time at room temperature.

The invention patent application of application number CN2015130352. X, named 'a modified neoprene rubber used in combination', discloses the use of NR to improve the problems of poor cold resistance, roll sticking during rubber mixing, easy scorching, high cost and the like, but NR is a nonpolar rubber, poor ozone resistance, oil resistance and fatigue resistance, is not suitable for products with higher performance requirements than CR, and does not involve that CR rubber mixtures can be stored for a long time at room temperature.

The papers "storage stability and processing scorch" and "measures to avoid scorch during storage and use of neoprene" relate only to measures to avoid scorch during storage and processing of neoprene raw rubber, do not relate to specific formulations and specific process methods, and do not mention any means by which CR mixes can be stored for a long period of time at room temperature.

Disclosure of Invention

Aiming at the problems that the prior unvulcanized chloroprene rubber is easy to crosslink and scorch, the invention provides the scorch-resistant CR unvulcanized rubber which is stored at room temperature for a long time and a preparation method thereof, and also comprises the preparation method of the scorch inhibitor.

The invention adopts the technical means for solving the problems that: a scorch resistant CR unvulcanized adhesive for long term storage at room temperature comprising: raw rubber, reinforcing filler, plasticizer, vulcanization accelerator, coupling agent, anti-aging agent, scorch retarder, active agent and processing aid, wherein the mass ratio of the components is as follows: raw rubber: 100 parts of reinforcing filler: 10-180 parts of plasticizer: 0-30 parts of vulcanization accelerator: 0.2-15 parts of coupling agent: 0-5 parts of an anti-aging agent: 0-16 parts of scorch retarder: 0.1-5 parts of active agent: 1-10 parts of a processing aid: 1-20 parts of raw rubber which is neoprene or a mixture of neoprene and more than one of chlorinated polyethylene, chlorohydrin rubber, polyvinyl chloride and ethylene propylene rubber, wherein the mass ratio of the neoprene to other polymers is 60:40-95:5.

Further, the chloroprene rubber is non-sulfur-regulated chloroprene rubber with medium-low Mooney viscosity, the chlorinated polyethylene is rubber-type CM with chlorine content of about 35%, the CM model is low Mooney type, and the polyvinyl chloride is paste resin high-elasticity product with medium-low polymerization degree.

Further, the reinforcing filler is one or more of carbon black, white carbon black, calcium carbonate, clay, silicate filler and talcum powder.

Further, the silicate filler is nano material strong micro powder, and the calcium carbonate is light calcium carbonate.

Further, when the white carbon black and the coupling agent are used together, the mass ratio of the white carbon black to the coupling agent is 10:0-10:2.

Further, the plasticizer is more than one of alkane oil, paraffin oil, naphthenic oil, aromatic oil, petroleum resin, rosin and dioctyl sebacate.

Further, the vulcanization accelerator is two or more of zinc oxide, ethylene thiourea, 1, 3-trimethylene-2-thiourea, 3-methyl-2-thiazolethione, N' -m-phenylenedimaleimide, insoluble sulfur, N-cyclohexyl-2-benzothiazole sulfenamide, dicumyl peroxide, bismorphone disulfide, N-oxydiethylene-2-benzothiazole sulfenamide, tetraethylthiuram disulfide and tetraethylthiuram monosulfide.

Further, the dosage of ethylene thiourea and 1, 3-trimethylene-2-thiourea is controlled below 0.8 part; the dosages of the tetraethylthiuram disulfide and the tetraethylthiuram monosulfide are not more than 1 part; the zinc oxide is indirect zinc oxide, and the dosage of the zinc oxide is not more than 4 parts.

Further, the antioxidant is at least one of antioxidant 2246, antioxidant ODA, antioxidant 1010, antioxidant 702, antioxidant 4020, antioxidant 3100 and microcrystalline wax.

Further, the scorch retarder is 3, 5-dibenzothiazyl salicylic acid.

Further, the active agent is more than one of magnesium oxide, stearic acid or stearate.

Further, the processing aid is at least one of tackifying resin, compatilizer, dispersing agent, curing agent, adhesive, exhaust flow agent and anti-sticking roller agent.

A preparation method of scorch-resistant CR unvulcanized rubber stored at room temperature for a long time comprises the steps of carrying out thin-pass or even blending on neoprene raw rubber or neoprene raw rubber and other high polymers on an internal mixer or an open mill to prepare a prefabricated rubber sheet, wherein the other high polymers are required to be uniformly mixed with a plasticizer, and then carried out thin-pass even and sheet-down on the open mill or the internal mixer; then adding the cooled prefabricated rubber sheet into an internal mixer or an open mill, adding an active agent, a reinforcing filler, a plasticizer, a coupling agent, a scorch retarder, other processing aids and the like, and discharging rubber after mixing at a low temperature to prepare a section of rubber compound; finally, after the first section of rubber compound is placed and cooled, adding a vulcanization accelerator and an anti-aging agent into an open mill for mixing, fully opening cooling water during open mill, reducing Wen Baotong, uniformly mixing, and then discharging to obtain the final mixed compound.

Further, the low-temperature mixing time is 6-15 minutes when preparing a section of rubber compound, and the rubber discharging temperature is not more than 115 ℃.

Further, the standing and cooling time of a section of rubber compound is more than 4 hours, and the time of Wen Baotong times is more than 5 times.

Further, the temperature of the rubber material in the whole process of preparing the final rubber compound is not more than 90 ℃.

A preparation method of a scorch retarder is characterized in that the scorch retarder is 3, 5-dibenzothiazyl salicylic acid, and is synthesized by adopting a one-step reaction method of 2-mercaptobenzothiazole and 3, 5-dibromosalicylic acid.

Further, the synthesis steps are as follows: adding 2-mercaptobenzothiazole (2.0-2.2 eq), 3, 5-dibromosalicylic acid (1.0 eq), sodium carbonate (3.0-5.0 eq), sodium iodide (0.1-1.0 eq) and ethanol solvent (50-80 eq) into a reaction container, and reacting at 50-80 ℃ in a nitrogen atmosphere for 24-48h; and after the reaction is finished, spin-drying the solvent, and vacuum drying to obtain the 3, 5-dibenzothiazyl salicylic acid.

The beneficial effects of the invention are as follows:

1. the invention uses a novel functional scorch inhibitor in combination with a rubber material with slower reaction in the formula, reduces the effective reactivity of CR, adopts low-temperature rubber mixing in the rubber mixing process, reduces the consumption of scorch time in the rubber mixing process, and combines three modes to obviously improve the scorch resistance and storage property of CR, thereby providing a CR unvulcanized rubber which can be stored at room temperature for a long time, has very excellent scorch safety and storage stability, and can be stored for 6 months at room temperature, and the CR unvulcanized rubber and a semi-finished product thereof still have good processing manufacturability, and have no obvious reduction of adhesive strength, flexibility, oil resistance, stretching property and the like of the product when being used for producing the finished product.

2. When the final mixed rubber is prepared, the open mill is adopted for vulcanizing mixing, and the cooling water is completely opened, so that the temperature is controlled below 90 ℃, and the scorching in the mixing process is reduced.

3. The functional group of the 3, 5-dibenzothiazyl salicylic acid scorch inhibitor salicylic acid can consume zinc oxide and magnesium oxide which are CR sizing material vulcanizing agents, and the group of the benzothiazole can react with accelerators such as sulfenamides and the like, thereby playing a role in dual scorch prevention and effectively improving the scorch resistance of CR.

Drawings

FIG. 1 is a molecular structure diagram of 3, 5-dibenzothiazyl salicylic acid according to the invention;

FIG. 2 shows the reaction scheme of 3, 5-dibenzothiazyl salicylic acid according to the invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings. Wherein the drawings are for illustrative purposes only and are shown in schematic, non-physical, and not intended to be limiting of the present patent; for the purpose of better illustrating embodiments of the invention, certain elements of the drawings may be omitted, enlarged or reduced and do not represent the size of the actual product; it will be appreciated by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

Example 1

This example shows the production of a scorch retarder, and 2-mercaptobenzothiazole (0.21 mol,35.0 g), 3, 5-dibromosalicylic acid (0.10 mol,29.6 g), sodium carbonate (0.3 mol,31.8 g), sodium iodide (0.02 mol,3.0 g) and an ethanol solvent (5.0 mol,288 mol) were charged into a reaction vessel, and reacted at 50-80℃in a nitrogen atmosphere for 24-48 h. After the reaction is finished, spin-drying the solvent, and vacuum drying to obtain the 3, 5-dibenzothiazyl salicylic acid shown in the figure 1, which is called DPNTS for short, wherein the reaction formula is shown in the figure 2.

The following examples two to four are CR unvulcanized rubber for long-term storage at room temperature, which is scorch-resistant, and a method for producing the same.

Example two

The sizing material comprises the following components in parts by mass: 100 parts of neoprene, 4 parts of high-activity magnesium oxide, 0.5 part of stearic acid, 20 parts of carbon black, 30 parts of white carbon black, 1 part of a coupling agent, 15 parts of alkane oil, 2 parts of indirect zinc oxide, 3 parts of bismorphone disulfide, 0.5 part of insoluble sulfur, 0.5 part of N-oxydiethylene-2-benzothiazole sulfenamide, 0.6 part of ethylene thiourea, 0.2 part of a functional scorch retarder, 3, 5-dibenzothiazyl salicylic acid and 2 parts of an anti-sticking roller agent.

The preparation process of the sizing material comprises the following steps: the chloroprene rubber is thinned and then is sliced on an open mill, and is put into an internal mixer or the open mill, and then carbon black, white carbon black, a coupling agent, a functional anti-scorching agent and an anti-sticking roller agent are put into the internal mixer, and after mixing for 12 minutes, rubber is discharged, the rubber discharging temperature is 108 ℃, and a section of rubber compound is prepared; putting the cooled first section of rubber compound into an open mill, fully opening cooling water of the open mill, uniformly wrapping rollers, then putting zinc oxide, bismorphone disulfide, insoluble sulfur, N-oxydiethylene-2-benzothiazole sulfenamide and ethylene thiourea into the open mill in batches, reducing Wen Baotong times, uniformly mixing, and then discharging the rubber compound, wherein the temperature of the rubber compound in the whole process is not more than 80 ℃, thus obtaining the CR rubber compound.

Example III

The sizing material comprises the following components in parts by mass: 75 parts of neoprene, 25 parts of chlorinated polyethylene CM, 5 parts of magnesium oxide, 0.7 part of stearic acid, 20 parts of calcium carbonate, 30 parts of white carbon black, 2.0 parts of coupling agent Si-69, 15 parts of naphthenic oil, 4 parts of indirect zinc oxide, 0.5 part of functional scorch retarder 3, 5-dibenzothiazyl salicylic acid, 0.3 part of 1, 3-trimethylene-2-thiourea, 2.0 parts of N, N' -m-phenylene bismaleimide, 0.3 part of N-cyclohexyl-2-benzothiazole sulfenamide and 1010 parts of antioxidant.

The preparation process of the sizing material comprises the following steps: adding 5-10 parts of naphthenic oil into chlorinated polyethylene powder according to the proportion of 100 parts of chlorinated polyethylene, uniformly stirring, and carrying out thin pass on a cold roll mill for more than 10 times until the film becomes uniform and semitransparent, and then feeding for later use; uniformly blending neoprene raw rubber and the thin-passing rubber sheet on a low-temperature open mill for 5 times according to the proportion of 75/25 to prepare CR/CM blended raw rubber, and cooling for standby after discharging; putting the CR/CM blended raw rubber into an internal mixer, putting a functional scorch retarder, calcium carbonate, white carbon black, a coupling agent and naphthenic oil into the internal mixer, mixing at a low temperature for 12 minutes, and discharging rubber at a rubber discharging temperature of 110 ℃ to prepare a section of rubber compound; putting the cooled first section of rubber compound into an open mill, fully opening cooling water of the open mill, uniformly wrapping rollers, then putting zinc oxide, 1, 3-trimethylene-2-thiourea, N' -m-phenylene bismaleimide, N-cyclohexyl-2-benzothiazole sulfenamide and an antioxidant into the open mill in batches, reducing the temperature by Wen Baotong times, uniformly mixing, then discharging the rubber compound, and preparing the rubber compound at the rubber discharging temperature of 85 ℃.

Example IV

The sizing material comprises the following components in parts by mass: 85 parts of neoprene, 15 parts of polyvinyl chloride, 4 parts of magnesium oxide, 0.5 part of stearic acid, 4 parts of indirect zinc oxide, 30 parts of calcium carbonate, 20 parts of white carbon black, 1.0 part of a coupling agent Si-69, 10 parts of paraffin oil, 0.3 part of a functional scorch retarder 3, 5-dibenzothiazyl salicylic acid, 0.5 part of sulfur, 1 part of 3-methyl-2-thiazolethione, 2 parts of bismorphone disulfide, 0.2 part of N-cyclohexyl-2-benzothiazole sulfenamide, 0.5 part of tetraethylthiuram monosulfide, 4020 part of an antioxidant and 9 2 parts of petroleum resin C.

The preparation process of the sizing material comprises the following steps: adding paraffin oil into polyvinyl chloride powder according to the proportion of 5-15 parts of polyvinyl chloride in 100 parts, uniformly stirring, uniformly passing through a cold roll mill, and blanking for later use; uniformly mixing neoprene rubber with the thin polyvinyl chloride film on a low-temperature open mill according to the proportion of 85/15 to prepare CR/PVC blended rubber, and cooling for standby after discharging; putting the CR/PVC blended raw rubber into an internal mixer, adding calcium carbonate, white carbon black, a coupling agent, a functional scorch retarder and petroleum resin, mixing for 15 minutes, and discharging rubber at 115 ℃ to prepare a section of rubber compound; after 8 hours of standing, carrying out secondary mixing, putting the primary mixed rubber, sulfur, 3-methyl-2-thiazole thioketone, dimorphine disulfide, N-cyclohexyl-2-benzothiazole sulfenamide, tetraethylthiuram monosulfide and an anti-aging agent into an open mill, mixing for 10 minutes, discharging rubber and discharging rubber, wherein the rubber discharging temperature is 90 ℃, and obtaining the CR mixed rubber.

After the CR rubber compound produced in the second to fourth embodiments is detected to be qualified according to the technical index requirements, the CR rubber compound can be used as a semi-finished rubber compound to be vulcanized, and can be put into a room temperature warehouse for standby, or can be prepared into a semi-finished product for standby according to the product requirements, wherein the semi-finished product can be an extruded rubber tube, an adhesive tape or the like, and is rolled on a three-roll calender to prepare a rubber sheet with a certain specification size, or is rolled with a framework material (such as glass fiber cloth, carbon fiber cloth, nylon Long Lianzi cloth or wirecord fabric or the like) to prepare an adhesive tape or the like.

To verify the properties of each of the compounds produced in the above examples two to four, the inventors prepared CR mixes for comparison by the following three comparative examples.

Comparative example 1

The material comprises the following components in parts by mass: 100 parts of neoprene, 4 parts of high-activity magnesium oxide, 0.5 part of stearic acid, 20 parts of carbon black, 30 parts of white carbon black, 1 part of a coupling agent, 15 parts of alkane oil, 2 parts of indirect zinc oxide, 3 parts of bismorphone disulfide, 0.5 part of insoluble sulfur, 0.3 part of dibenzothiazyl disulfide, 0.6 part of ethylene thiourea and 2 parts of an anti-sticking roller agent.

The preparation process of the sizing material comprises the following steps: the chloroprene rubber is thinned and then is sliced on an open mill, and is put into an internal mixer or the open mill, and then carbon black, white carbon black, a coupling agent and an anti-sticking roller agent are put into the internal mixer, and the rubber is discharged after 25 minutes of mixing, wherein the rubber discharge temperature is 129 ℃ to prepare a section of rubber compound; putting the cooled first section of rubber compound into an open mill after 8 hours of cooling, fully opening cooling water of the open mill, putting zinc oxide, bismorphone disulfide, insoluble sulfur, dibenzothiazyl disulfide and ethylene thiourea into the open mill in batches after the rollers are uniformly covered, putting the lower temperature of the rubber compound into a plate after the rubber compound is uniformly mixed for Wen Baotong times, and preparing the CR rubber compound at the rubber discharging temperature of 110 ℃.

Comparative example 2

The material comprises the following components in parts by mass: 75 parts of neoprene, 25 parts of chlorinated polyethylene CM, 4 parts of magnesium oxide, 0.7 part of stearic acid, 20 parts of calcium carbonate, 30 parts of white carbon black, 2.0 parts of coupling agent Si-69, 15 parts of naphthenic oil, 5 parts of indirect zinc oxide, 0.8 part of 1, 3-trimethylene-2-thiourea, 2.0 parts of N, N' -m-phenylene bismaleimide, 0.3 part of N-cyclohexyl-2-benzothiazole sulfenamide and 1010 parts of antioxidant.

The preparation process of the sizing material comprises the following steps: adding 5-10 parts of naphthenic oil into 100 parts of CM, uniformly stirring, and carrying out thin pass on a cold roll mill for more than 10 times until a film becomes uniform and semitransparent, and then feeding for later use; uniformly blending neoprene rubber and the thin CM film on a low-temperature open mill for 5 times according to the proportion of 75/25 to prepare CR/CM blended rubber, and cooling for standby after film falling; putting the CR/CM blended raw rubber into an internal mixer, then putting calcium carbonate, white carbon black, a coupling agent and naphthenic oil into the internal mixer, mixing for 25 minutes at a low temperature, and discharging rubber at a temperature of 130 ℃ to prepare a section of rubber compound; putting the cooled first section of rubber compound into an open mill, fully opening cooling water of the open mill, uniformly wrapping rollers, then putting zinc oxide, 1, 3-trimethylene-2-thiourea, N' -m-phenylene bismaleimide, N-cyclohexyl-2-benzothiazole sulfenamide and an antioxidant into the open mill in batches, reducing the temperature by about Wen Baotong times, uniformly mixing, then discharging the rubber at 90 ℃ to prepare the rubber compound.

Comparative example 3

The material comprises the following components in parts by mass: 85 parts of neoprene, 15 parts of polyvinyl chloride, 4 parts of magnesium oxide, 0.5 part of stearic acid, 5 parts of indirect zinc oxide, 30 parts of calcium carbonate, 20 parts of white carbon black, 1.0 part of a coupling agent Si-69, 10 parts of paraffin oil, 0.5 part of sulfur, 1 part of 3-methyl-2-thiazolethione, 2 parts of bismorphone disulfide, 0.5 part of N-cyclohexyl-2-benzothiazole sulfenamide, 0.5 part of tetraethylthiuram monosulfide, 4020 part of an anti-aging agent and 9 2 parts of petroleum resin C.

The preparation process of the sizing material comprises the following steps: adding paraffin oil into polyvinyl chloride powder according to the proportion of 10-15 parts of polyvinyl chloride in 100 parts, uniformly stirring, and uniformly discharging slices on a cold roll mill; uniformly blending neoprene raw rubber and the thin passing polyvinyl chloride film on a low-temperature open mill for 5 times according to the proportion of 85/15 to prepare CR/PVC blended raw rubber, and cooling for standby after film falling; putting the CR/PVC blended raw rubber into an internal mixer, putting calcium carbonate, white carbon black, a coupling agent and petroleum resin into the internal mixer, mixing for 25 minutes, and discharging rubber at 128 ℃ to prepare a section of rubber compound; after 8 hours of standing, carrying out secondary mixing, putting the primary mixed rubber, sulfur, 3-methyl-2-thiazole thioketone, dimorphine disulfide, N-cyclohexyl-2-benzothiazole sulfenamide, tetraethylthiuram monosulfide and an anti-aging agent 4020 into an internal mixer, mixing for 10 minutes, discharging rubber, and obtaining the CR mixed rubber at the temperature of 100 ℃.

The rubber compound properties of examples two to four and comparative examples 1 to 3 were examined respectively, and the results are shown in the following table:

from the table above, it can be seen that the compounds of examples two to four have not only good tensile properties, excellent adhesion properties, flex resistance and ozone aging resistance, but also very excellent scorch safety and storage property, still have good scorch safety and fluidity after being parked for 6 months at room temperature, and the interlayer adhesive strength of the compounds after being parked for 6 months is still higher without significant decrease.

The rubber materials of the second to fourth examples are rolled with a framework material (glass fiber cloth, carbon fiber cloth or nylon cloth) on a three-roll or four-roll calender at 70-120 ℃ to prepare an adhesive tape, and the adhesive tape is placed for 6 months and then subjected to performance detection, wherein the results are shown in the following table:

from the table above, it can be seen that the adhesive tapes formed by calendering the adhesive materials of the second to fourth embodiments have good paving property and manufacturability within 6 months of standing at room temperature, and the interlayer adhesive strength between the adhesive tapes is high, so that the performance requirements of products such as adhesive tapes, air springs, aprons, paddle heating assemblies and the like can be met. While the sizing materials of the comparative examples 1 to 3 have scorching phenomenon during the rolling of the sizing materials, no qualified sizing materials can be rolled, but the sizing materials of the examples are very smooth during the rolling process of the sizing materials, and the pressed sizing materials are flat and smooth.

As can be seen from the above examples, the CR rubber material of the present invention has excellent physical properties such as tensile property, adhesive strength, etc., and the unvulcanized rubber has excellent scorch resistance and storage stability, and can be stored for 6 months at room temperature (23+ -2 ℃) without scorching, and the storage period is long; in addition, the rubber material has excellent processing technology performance, can meet the technological requirements of extrusion, calendaring and the like, can be processed into semi-finished products such as films or rubberized fabrics and the like, still has good manufacturability and physical properties after being parked for 6 months at room temperature, and can meet the technological requirements and the product performance requirements of products. The problem that the neoprene rubber compound is easy to burn is solved, the neoprene rubber compound or semi-finished product has enough scorch safety in long-time transportation and storage, the problem of scrapping caused by early crosslinking is avoided, and the manufacturing of neoprene products, the takeout of CR rubber compound and the consignment of the substitute processing business of other rubber and plastic enterprises are smoothly carried out.

The above embodiments are only for illustrating the present invention, not for limiting the present invention, and various changes and modifications may be made by one skilled in the relevant art without departing from the spirit and scope of the present invention, so that all equivalent technical solutions shall fall within the scope of the present invention, which is defined by the claims.

Claims (8)

1. The preparation method of the scorch retarder is characterized in that the scorch retarder is 3, 5-dibenzothiazyl salicylic acid and is prepared by the following steps: the 3, 5-dibenzothiazyl salicylic acid is synthesized by adopting a one-step reaction method of 2-mercaptobenzothiazole and 3, 5-dibromosalicylic acid, and the structural formula of the scorch retarder is as follows:

2. the method for producing a scorch retarder according to claim 1, wherein: the synthesis steps of the 3, 5-dibenzothiazyl salicylic acid are as follows: adding 2-mercaptobenzothiazole, 3, 5-dibromosalicylic acid, sodium carbonate, sodium iodide and ethanol solvent into a reaction container, and reacting for 24-48h at 50-80 ℃ in a nitrogen atmosphere; after the reaction is finished, spin-drying the solvent, and vacuum drying to obtain 3, 5-dibenzothiazyl salicylic acid; wherein the ratio of the reaction dosage is as follows: 2-mercaptobenzothiazole: 3, 5-dibromosalicylic acid: sodium carbonate: sodium iodide: ethanol solvent = 2.0-2.2eq:1.0eq:3.0 to 5.0eq:0.1-1.0eq:50-80eq.

3. A scorch resistant CR unvulcanized adhesive for long term storage at room temperature, characterized in that: the components comprise: raw rubber, reinforcing filler, plasticizer, vulcanization accelerator, coupling agent, anti-aging agent, scorch retarder, active agent and processing aid, wherein the mass ratio of the components is as follows: raw rubber: 100 parts of reinforcing filler: 10-180 parts of plasticizer: 0-30 parts of vulcanization accelerator: 0.2-15 parts of coupling agent: 0-5 parts of an anti-aging agent: 0-16 parts of scorch retarder: 0.1-5 parts of active agent: 1-10 parts of a processing aid: 1-20 parts of raw rubber which is neoprene or a mixture of neoprene and more than one of chlorinated polyethylene, chlorohydrin rubber, polyvinyl chloride and ethylene propylene rubber, wherein the mass ratio of the neoprene to other polymers is 60:40-95:5; wherein the scorch retarder is prepared by the method of claim 1;

the preparation process of the CR unvulcanized rubber comprises the following steps: the preparation method comprises the steps of (1) carrying out thin-pass or even blending on neoprene raw rubber or neoprene raw rubber and other polymers on an internal mixer or an open mill to prepare a prefabricated film, wherein the other polymers are required to be evenly mixed with a plasticizer first, then carrying out thin-pass on the prefabricated film on the internal mixer or the open mill evenly, and then discharging the prefabricated film; then adding the cooled prefabricated rubber sheet into an internal mixer or an open mill, adding an active agent, a reinforcing filler, a plasticizer, a coupling agent, a scorch retarder and other processing aids, and discharging rubber after mixing at a low temperature to prepare a section of rubber compound; finally, after standing and cooling the first section of rubber compound, adding a vulcanization accelerator and an anti-aging agent into an open mill for mixing, wherein cooling water is fully opened during open mill, wen Baotong is reduced, and the rubber compound is produced after uniform mixing and blanking;

wherein the low-temperature mixing time is 6-15 minutes when preparing a section of mixed rubber, and the rubber discharging temperature is not more than 115 ℃;

the standing and cooling time of a section of rubber compound is more than 4 hours, and the time of Wen Baotong times is more than 5 times;

the temperature of the sizing material in the whole process of preparing the final rubber compound is not more than 90 ℃.

4. A scorch resistant CR unvulcanized adhesive for long term storage at room temperature as set forth in claim 3, characterized in that: the reinforcing filler is one or more of carbon black, white carbon black, calcium carbonate, clay, silicate filler and talcum powder;

the plasticizer is more than one of alkane oil, paraffin oil, naphthenic oil, aromatic hydrocarbon oil, petroleum resin, rosin and dioctyl sebacate; the vulcanization accelerator is more than two of zinc oxide, ethylene thiourea, 1, 3-trimethylene-2-thiourea, 3-methyl-2-thiazole thioketone, N' -m-phenylene bismaleimide, sulfur, N-cyclohexyl-2-benzothiazole sulfenamide, dicumyl peroxide, bismorphone disulfide, N-oxydiethylene-2-benzothiazole sulfenamide, tetraethylthiuram disulfide and tetraethylthiuram monosulfide;

the antioxidant is at least one of antioxidant 2246, antioxidant ODA, antioxidant 1010, antioxidant 702, antioxidant 4020, antioxidant 3100 and microcrystalline wax;

the scorch retarder is 3, 5-dibenzothiazyl salicylic acid;

the active agent is more than one of magnesium oxide, stearic acid or stearate;

the processing aid is more than one of tackifying resin, compatilizer, dispersing agent, curing agent, adhesive, exhaust flow agent and anti-sticking roller agent.

5. The scorch resistant CR unvulcanized adhesive for long term storage at room temperature as set forth in claim 4, further comprising: the silicate filler is nano material strong micro powder, and the calcium carbonate is light calcium carbonate.

6. The scorch resistant CR unvulcanized adhesive for long term storage at room temperature as set forth in claim 4, further comprising: when the white carbon black and the coupling agent are used together, the mass ratio of the white carbon black to the coupling agent is 10:0-10:2.

7. The scorch resistant CR unvulcanized adhesive for long term storage at room temperature as set forth in claim 4, further comprising: the dosage of ethylene thiourea and 1, 3-trimethylene-2-thiourea is controlled below 0.8 part; the dosages of the tetraethylthiuram disulfide and the tetraethylthiuram monosulfide are not more than 1 part; the zinc oxide is indirect zinc oxide, and the dosage of the zinc oxide is not more than 4 parts.

8. A process for preparing a CR unvulcanized adhesive for long-term storage at room temperature, which realizes scorch protection as set forth in claim 3, characterized in that: the preparation method comprises the steps of (1) carrying out thin-pass or even blending on neoprene raw rubber or neoprene raw rubber and other polymers on an internal mixer or an open mill to prepare a prefabricated film, wherein the other polymers are required to be evenly mixed with a plasticizer first, then carrying out thin-pass on the prefabricated film on the internal mixer or the open mill evenly, and then discharging the prefabricated film; then adding the cooled prefabricated rubber sheet into an internal mixer or an open mill, adding an active agent, a reinforcing filler, a plasticizer, a coupling agent, a scorch retarder and other processing aids, and discharging rubber after mixing at a low temperature to prepare a section of rubber compound; finally, after standing and cooling the first section of rubber compound, adding a vulcanization accelerator and an anti-aging agent into an open mill for mixing, wherein cooling water is fully opened during open mill, wen Baotong is reduced, and the rubber compound is produced after uniform mixing and blanking;

wherein the low-temperature mixing time is 6-15 minutes when preparing a section of mixed rubber, and the rubber discharging temperature is not more than 115 ℃;

the standing and cooling time of a section of rubber compound is more than 4 hours, and the time of Wen Baotong times is more than 5 times;

the temperature of the sizing material in the whole process of preparing the final rubber compound is not more than 90 ℃.

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