CN111187515A

CN111187515A - Production method of flame-retardant heat-resistant silicone rubber

Info

Publication number: CN111187515A
Application number: CN202010048094.5A
Authority: CN
Inventors: 吴善同
Original assignee: Sichuan Tower Cable Winding Wire Co Ltd
Current assignee: Sichuan Tower Cable Winding Wire Co Ltd
Priority date: 2020-01-16
Filing date: 2020-01-16
Publication date: 2020-05-22

Abstract

A production method of flame-retardant heat-resistant silicone rubber comprises the following steps: s1, after a mixing roll is opened and heated to the working temperature, adding and kneading 100 parts of methyl vinyl phenyl silicone rubber, gas phase white carbon black and hydroxyl silicone oil; s2, after the temperature in the mixing roll reaches 70-80 ℃, adding 1-3 parts of polyether silicone oil and a coloring agent, heating to 140 ℃ and 150 ℃, and kneading; s3, heating to 150-160 ℃, vacuumizing, performing condensation washing during vacuum maintenance, discharging, and standing for more than 24 hours; s4, back-refining the mixed colloid after standing on a two-roll machine, thinly passing the mixed colloid for multiple times, adding 8-20 parts of dicumyl peroxide, uniformly mixing, thinly passing the mixed colloid again, discharging sheets, and standing for 3-4 hours; and (4) curing, and then drying while finishing curing to obtain a finished product. The silicon rubber obtained by the invention can meet the American UV-94-0 standard requirement through testing, and the silicon rubber can be extinguished within 2 seconds after being ignited and separated from the open fire, and the tensile strength, the elongation at break and the resistivity are all improved to a certain extent.

Description

Production method of flame-retardant heat-resistant silicone rubber

Technical Field

The invention relates to the field of rubber processing, in particular to a production method of flame-retardant heat-resistant silicone rubber.

Background

The extrusion molding silicon rubber cable is a new cable variety developed in recent 20 years, the integral content of silicon dioxide on the earth is up to 27%, and with the increase of the cost of natural rubber and synthetic rubber, the silicon rubber technology produced by using natural silicon dioxide raw materials is continuously broken through. The traditional production technology of original rubber utilizes materials such as PVC, PE to produce the cable, adopts the thermoplasticity type processing mode, and the cable surface winding has multilayer asbestos and PE membrane, and some cables still need add the armor shielding, and silicon rubber adopts hot-air vulcanization technique, and simple process, and the production process is energy-concerving and environment-protective more.

Disclosure of Invention

Aiming at the technical defects in the prior art, a silicone rubber product with better performance is developed, and the invention discloses a production method of flame-retardant heat-resistant silicone rubber.

The production method of the flame-retardant heat-resistant silicone rubber comprises the following steps:

s1, after the mixing roll is opened and heated to the working temperature, 100 parts of methyl vinyl phenyl silicone rubber and 15-20 parts of gas phase white carbon black are added and kneaded; adding 15-20 parts of gas-phase white carbon black after kneading and rolling, adding hydroxyl silicone oil, kneading for 5 minutes, and then adding 15-20 parts of gas-phase white carbon black;

s2, after the temperature in the mixing roll reaches 70-80 ℃, adding 1-3 parts of polyether silicone oil and a coloring agent, heating to 140-150 ℃, and kneading for 45-90 minutes;

s3, heating to 150-160 ℃, vacuumizing to 0.7-0.9 MPa, maintaining for more than 30 minutes, discharging after condensation and washing during the vacuum maintenance period, and standing for more than 24 hours;

s4, back-refining the mixed colloid after standing on a two-roll machine, thinly passing the mixed colloid for multiple times, adding 8-20 parts of dicumyl peroxide, uniformly mixing, thinly passing the mixed colloid again, discharging sheets, and standing for 3-4 hours; feeding the thin-passed rubber material into an extruder for discharging and vulcanizing, and obtaining a finished product after vulcanization is finished; the parts are parts by weight.

Specifically, the colorant is 4-8 parts of oil-soluble carbon black.

Preferably, the temperature interval of the vulcanization is sequentially carried out in three sections: the first stage is at 80-100 ℃ for 1-2 minutes; the temperature of the second section is 100 ℃ and 120 ℃, and the time is 1-2 minutes; the temperature of the third section is 150 ℃ and 160 ℃, and the time is 2-4 minutes

The invention has the following advantages:

firstly, the silicon rubber obtained by the invention can meet the American UV-94-0 standard requirement through testing, and the silicon rubber is extinguished within 2 seconds after an open fire is ignited, so that the tensile strength, the elongation at break and the resistivity are improved to a certain extent.

The process mode of the invention is completely compatible with the existing silicon rubber production process, the existing mature equipment can be adopted to directly assemble a production line for production, and the equipment modification cost is low.

The main material of the raw material is methylvinyl phenyl silicone rubber, the auxiliary material is common economic chemical raw material, the comprehensive production cost is lower than 25 yuan RMB/kg, and the market competitiveness is strong.

Drawings

FIG. 1 is a schematic flow chart of a specific implementation of the method for producing the flame-retardant and heat-resistant silicone rubber of the invention.

Detailed Description

The embodiments of the present invention will be described in more detail with reference to the accompanying drawings and reference numerals, so that those skilled in the art can implement the embodiments of the present invention after studying the specification. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The production method can be carried out on the basis of the following equipment: kneaders or open mixers, open two-roll machines, extruders and drying tunnels.

The raw materials comprise the following components:

100 parts of methyl vinyl phenyl silicone rubber,

wherein the molar ratio of the vinyl groups is 0.15 percent; n, m and j represent different degrees of aggregation of the molecules.

50 parts of gas-phase white carbon black,

10 parts of hydroxyl silicone oil, namely 10 parts of hydroxyl silicone oil,

10 parts of dicumyl peroxide (DCP),

6 parts of oil-soluble carbon black,

and 2 parts of polyether silicone oil.

The main process comprises the following steps:

heating the mixing roll to the working temperature after the mixing roll is opened, starting feeding, firstly adding all methyl vinyl phenyl silicone rubber and one third of gas phase white carbon black, adding one third of gas phase white carbon black after kneading and rolling, adding hydroxyl silicone oil, kneading for 5 minutes, and then adding the rest gas phase white carbon black; the gas phase white carbon black is used as a reinforcing agent of the material, so that the mechanical strength and hardness of a finished product can be improved, and the hydroxyl silicone oil is used as a structure control agent, so that the hardening of a rubber material can be avoided, and the processing and modification are facilitated.

After the internal temperature of the mixing roll reaches 70-80 ℃, adding polyether silicone oil and oil-soluble carbon black, heating to 140-150 ℃, and kneading for about 1 hour. Oil-soluble carbon black is mainly used as a coloring agent of the cable; the polyether silicone oil is doped into the cable, so that the flexibility of the cable is enhanced, and the produced cable has the advantages of smooth surface, small tension and small tension: rainwater, snow water and the like are not easy to stay on the surface of the cable for a long time, and the phenomenon of icing can not occur if no residual water exists on the surface of the cable in winter.

And then heating to 150-160 ℃, vacuumizing to 0.7-0.9 MPa, maintaining for 30 minutes, turning on a condensed water switch of the mixing roll during the period of maintaining vacuum, discharging after condensation and washing, standing for more than 24 hours, and vacuumizing to enable dust and moisture in the mixture to escape from the interior of the mixture more easily so as to facilitate subsequent cleaning.

And (3) back-refining the mixed colloid after standing on a two-roll machine, thinly passing the mixed colloid for three times to enable various components to be mixed more uniformly, then adding dicumyl peroxide for mixing uniformly, thinly passing the mixed colloid again, discharging the mixed colloid, and standing for 3-4 hours.

The specific reaction equation is as follows:

n, n1, n2, m1, m2, j1, j2, k represent different degrees of aggregation of molecules;

the main reaction mechanism is that under the action of a catalyst, vinyl in a molecular group is opened and is bonded with adjacent molecules in three dimensions in space to form a three-dimensional structure, and partial methyl is dehydrogenated to form hydrogen bonds to participate in the linkage of the molecular group to form a three-dimensional polymer of the methyl vinyl phenyl silicone rubber.

Feeding the thin rubber material into an extruder for discharging and vulcanizing，The temperature interval for the vulcanization can be carried out in three stages in sequence.

The first stage is at 80-100 ℃ for 2 minutes;

the temperature of the second section is 100 ℃ and 120 ℃, and the time is 2 minutes;

the temperature of the third section is 150 ℃ to 160 ℃, and the time is 3 minutes.

The sectional process is adopted, so that the vulcanization process is more uniform, and the materials are not easy to crack and bubble in the vulcanization process.

The silicon rubber obtained by the invention can meet the American UV-94-0 standard requirement through testing, and the silicon rubber can be extinguished within 2 seconds after being ignited and separated from the open fire, and the tensile strength, the elongation at break and the resistivity are all improved to a certain extent.

The properties of the obtained product were compared with those of a rubber of KE4603-1 type in Japan shin-Etsu chemical as shown in the following table.

While the invention has been described in terms of various specific embodiments, it will be understood that the invention is not limited to the specific details disclosed herein. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the spirit of the invention, which falls within the scope of the invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A production method of flame-retardant heat-resistant silicone rubber is characterized by comprising the following steps: the method comprises the following steps:

2. The method for producing a flame-retardant, heat-resistant silicone rubber according to claim 1, wherein the colorant is 4 to 8 parts of oil-soluble carbon black.

3. The method for producing a flame-retardant and heat-resistant silicone rubber according to claim 1, wherein the vulcanization is carried out in three stages in sequence: the first stage is at 80-100 ℃ for 1-2 minutes; the temperature of the second section is 100 ℃ and 120 ℃, and the time is 1-2 minutes; the temperature of the third section is 150 ℃ and 160 ℃, and the time is 2-4 minutes.