silicone rubber bladder coating system as a process aid for curing tires.

by:Keyuan     2020-06-13
Tire maintenance airbags have experienced some of the worst operating conditions.
These include high temperature, severe bending, common
Vulcanization and migration of chemicals in uncured tires.
Its production life has a significant impact on the operation efficiency of the tire factory.
This paper will describe the room temperature vulcanization silicone rubber currently used to extend the life of the bladder.
Before the new airbag is installed on the tire press, the airbag coating is applied to the new airbag.
Starting with the first tire, very counter
Adhesive surface properties of silicone rubber protect the bladder from co-
Vulcanization, after processing can easily separate the vulcanization tire.
No bladder coating, mold release from the internal tire mold release agent.
Before the uncured tire is pressed and cured, the internal tire release agent is produced inside the uncured tire.
After each treatment, transfer from the tire to the release membrane of the new bladder.
Adequate coverage of the bladder may require up to 60 healing cycles.
Without bladder coating, the production life of the new bladder depends on the coverage of the release agent sprayed inside each tire.
If the mold release agent has poor atomization and poor coverage, the area not sprayed will cross
Connect and aggregate with the new bladder.
The bladder coating is prepared with a dimethyl silicone lubricant, but the quantity is not sufficient to provide continuous lubrication after several treatments.
Lubrication and gas introduction are provided by a variety of available water-based silicone lotions mixed with fillers, such as cloud powder, talc and clay.
The lubricating oil is formulated according to the special customer requirements of the tire type and its process.
Thus, the bladder coating is part of the system, and the lubricant can be applied inside or directly to the bladder on an uncured tire.
Between the airbag and the tire, plus the lubricant, you can provide excellent release slip and air leakage.
This paper will review the laboratory work to characterize the performance of various lubricant bladder coatings.
The study aimed to establish the release, lubrication and wear resistance of silicone rubber as the coating of tire curing airbag.
These properties are evaluated by the use of a repeated curing cycle of uncured Ding lining and friction agent compounds.
This method does not bend nor stretch the butyl material, but uses temperature, curing time and pressure conditions similar to the production of passenger car tires.
This article will introduce usingten-performing thebladder coating and inner-free tire mold release agent-
Minutes of treatment in Jingdong.
The curator who migrated from the hot pot compound was serious about Ding bladder and silicone rubber coating.
The evaluation of the bladder coating of the experimental material was carried out with bladder compounds from an undisclosed tire company.
Even if the actual formula is not revealed, it is also a formula (ref. 1)
Typical and representative of the current industry (table 1).
The same undisclosed company also provided inventory of the halogen substitute Zhengding inner lining and these two hot pot compounds.
The formula of Halo Zhengding liner is proprietary, while the undisclosed hot pot formula is a typical formula (ref. 2)
This can be found when searching for industrial technical literature (tables 2 and 3).
Bladder coated VP-
1069 is a one-component room temperature vulcanization product imported from Wacker Chemical Company.
It is composed of an amino-functional silicone cross-link and a filler dispersed in naphtha, weighing 47% solids.
The mold release agent in the tire is Wacker silicone products.
The water in the tire mold release agent \"A\" is similar, but it is not Wacker\'s product.
Within 375oF 15 minutes, solidify the inventory of the bladder into 6 × 0. 075 inch panels.
Wipe clean with PX before coating and then dry for at least 24 hours.
The cleaning panel is coated by immersing them in a solution of the bladder coating (
Calculated by weight, 3 parts of toluene in 2 parts).
By placing the surface coated panel in force-
215 [air oven]degrees]
15 minutes.
Then, before using the panel, the coating on the bladder is allowed to cure the air for at least 48 hours under ambient conditions.
In this way, the average dry coating weight is about 50g/s.
It\'s about two thick Mills. 50 microns)
, Comparable to the number of bladder applications in this field.
The water-based Inner mold release agent of the tire is brushed on the pre-cut calender plate of the uncured halogen-Butin lining and friction material.
These sheets are 5-
3/4 square meters, 1/10 of inchthick.
The coating dries at room temperature for at least 24 hours. The cure-release-
Lubrication experiments are carried out under conditions similar to the tire mold.
However, the lack of stretching and bending reduces the severity of the test.
In the four-cavity mold, after curing in the Middle East and 139 pounds minutes per square inch, the uncured lining is re-replaced on each bladder panel.
After each curecycle, the lubrication between the liner and the bladder panel is measured.
Using the instrument slide/Peel tester model SP-measure the static and dynamic coefficients of friction
At 360buy 101B, the speed is 12 inch per minute under sledding pressure of 7 pounds/inch.
Repeat the process until all treatment cycles are completed.
Lubrication using six minutes, the total heat exposure time after 100 curing cycles is equivalent to about 27 hours in the oven.
Results and discussion
Coated airbags tested with in-tire mold release agent Figure 1 shows the lubrication results of each of the four experiments
Coated bladder plate and halogen-
Tire mold release agent coated with inner tire mold release agent \"A\", E255, xe529503 and e268.
The average inner-painted dry coatweight per square meter of tires is 55 grams.
The mean and standard deviation of these results are recorded in the legend of the figure. For the non-
The sequence of the coated bladder from the easternmost color is as follows: static: E268 [
Much bigger]E255 [Greater than]XE529503[Greater than]
[A] dynamic: E268 【
Much bigger]\"A\" [
Approximately equal)E255 [Greater than]XE529503 [
Figure 1 illustration omitted]
Figure 2 shows the results between coated airbags released according to \"A\", E255, XE529503, and e268.
For the coated bladder, the order from the most to the least color is as follows: static: E268 [
Much bigger]E255 [Greater than]XE529503[
Approximately equal
[A] dynamic: E268 【
Much bigger]\"A\" [
Approximately equal)E255 [
Approximately equalXE529503 [
Figure 2 illustration omitted]
Tables 4 and 5 show no significant difference whether or not we have non-lubrication
Coated or coated bladder panel.
These results confirm that lubrication is mainly controlled by the type of aid applied to the lining.
Test the coated bladder with uncured Ding lining and friction material to determine the chemical compatibility effect on the bladderrelease-
Repeat the lubrication experiment without paint inside the tire.
Figures 3 and 4 show the results between the coated bladder and the non-coated bladder
Coated halogen-butaline liner, friction agent compound for passengers and truck tires.
The order from the most to the least color is as follows: static: Passenger hot pot is about equal to]
[Ding lining]Greater than]
Hot pot dynamics of trucks: Passenger hot pot 【
Approximately equal
[Ding lining]Greater than]truck chafer [
Figure 3 illustration omitted]
After several successive curing cycles, the transparent bladdercoating gradually becomes a translucent white coating.
The initially elastic silicone rubber coating gradually became a very soft gel-
Like consistency
The order in which this change is caused by the uncured stock is as follows: truck tire friction machine [
Much better than this.
Hot pot passenger tires 【:Greater than]
The components migrated from the inside of the tirerelock agent can increase the bladder coating compared to the uncured inventory.
Due to this process, the coating is gel-like and easily worn out.
Figure 4 exemplary results between coated airbags released according to four experimental variations of the tire release agent xe529602.
These products are formulated with different lubricants and have been tested for compatibility with the bladder coating. The cure-release-
The lubrication experiment lasted until the coating was worn out.
For lubricants B and C, the wear of the coating is severe enough that the efficiency of friction begins to increase after 120 treatment.
Lubrication preparations A and D are more compatible with treatment times exceeding 240 times before any significant changes are observed.
This method has proved to be an effective screening tool for evaluating new products of bladder coating. [
Figure 4 illustration omitted]Cure-release-
Experiment of thermal aging and lubricationrelease-
The lubrication experiment was compared with the heating process in the forced air oven.
The basic principle of heat aging testicles is to expose the cured bladder panel to high temperature for a period of time in a forced air oven.
The deterioration of rubber in the air oven is due to the combined effect of oxidation and thermal aging.
360 [50 hours]degrees]
F in forced airoven, it is estimated that the total heat exposure is more severe than the 300 cure on the bladder of a typical tire plant.
Unlike our Test team in the forced air oven, the steam side of the bladder is 360 [degrees]
F, while the outer surface of the cooler is only exposed to air when the mold is opened. For all cure-release-
The lubrication experiment determined the stretching and compared it with the original value.
Figure 5 shows a decrease in elongation within 50 hours in the case of 360 [degrees]
F of coating and non-coating
Coated bladder panel.
After 27 hours in forced airoven, the elongation shows a slight difference between the coating 2. 8 [+ or-]0. 1, and non-
Coated panel, 2. 6 [+ or -]0. 1.
The Insidetire paint experiment showed a similar effect, but there was more overlap between co3. 1 [+ or -]0.
4. no coating panel, 2. 9 [+ or -]0. 4.
There is a large difference between the stocks of uncured liners.
At one extreme, the total absence exposed to any uncured rubber represents a pair of controls.
One control is the \"T\" at the top and the other is the \"B\" Ding bladderpanel at the bottomrelease-
Lubrication experiment.
Control the mean values of \"T\" and \"B\" to 3. 5 [+ or -]0.
The average inventory of passengers and truck drivers is 2. 4 [+ or -]0. I.
At 3 H, the endogenous results of halogen Diding were slightly lower than those of the control \"T\" and \"B \". 1 [+ or -]0. 3.
All in all, the bladder coating has a certain degree of protection for the oxidation of the bladder panel.
In the left-hand chart of offigure 5, the coating panel shows that the elongation remains longer.
The diffusion of air through the silicon film delays the oxidation process.
It can be seen that as oxidation is allowed to continue, the change in elongation tends to be consistent with the change in non-elongation
Coating the bladder panel after 50 hours.
The lower right corner chart in Figure 5 shows that another process other than oxidation strongly affects the properties of the bladder.
The loss of elongation exposed to friction compounds is higher compared to thermal aging.
High efficacy levels in these compounds are most likely to lead to rapid aging of the bladder and bladdercoating.
To sum up this work, we have determined that effective bladder coating systems can be developed using experimental data.
Although the bladder coating, together with the water-based silicone emulsion, has increased the life of the bladder in this field by up to 100%, the migration of curatives in never-vulcanization tires remains the most demanding challenge.
To achieve higher performance, development will focus not only on systems that are more migration-resistant components, but also on systems designed to eliminate volatile organic compounds.
These systems may eventually include a product of 100% solids or a water-based system. References[1. ]W. H. Waddell, R. S. Bhakuni, W. W. Barbin and P. H.
Sanetrom, \"inflatable tire composite\", Van der Burt rubber manual, 13 thed. (1990). [2. ]
Smithsonian scientific services
File 9612 C.
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