properties of a new carboxylated vp-latex on the adhesion of pet tire cord to rubber.
The study of latex adhesion of PET tire cord to rubber the advent of radial car tires, with its superior driving stability, low fuel consumption and long life, has led to the demand for high-modulus tire curtain materials.
Although the nylon rope has been used for many years, it is not suitable for radial tires due to its tendency to stretch.
In order to meet the demand of radial tires, it is found that Polyester ropes have a good balance in quality and price.
However, Polyester ropes are not used for heavy-duty tires because the adhesion of ropes to rubber is reduced as the tire mileage increases.
In order to solve the problem of deterioration of adhesion, progress has been made in tire manufacturing, fiber and adhesive treatment, but no complete solution has been reached (ref. 1).
Nipon Zeon is trying to solve this problem by improving the latex part of the adhesive to increase adhesion and longer mileage.
It is speculated that due to the ester bond of the amine compound migrating from the rubber part, the adhesion between the polyester and the rubber decreases with the increase of mileage (ref. 2).
Although the Polyester Tire Cord is covered with adhesive, it is found that amine compounds penetrate into the polyester layer.
Therefore, it is theoretically believed that the adhesion force can be improved if the adhesive layer can prevent amine migration into polyester.
A test method for evaluating the degradation degree of polyester was developed.
The mechanism of preventing amine compounds from passing through the adhesive layer was studied.
The result is the development of a carboxyl vinylpyridine latex that can effectively protect polyester from amine compounds in rubber compounds.
A standard vinylbutadiene-
Tripolymer emulsion of Ding benzene and an aromatic vinyl benzamine-butadiene-
The styrene emulsion was used in these experiments (ref. 3).
These lotions are compounded into interphenol-formaldehyde-latex (RFL)
Adhesive in Table 1.
Evaluation of polyester protection by latex PET film strength measurement method
As shown in Figure 1a, laminated samples are prepared with polyethylene ester (PET)
Film, RFL adhesive and rubber compound, vulcanization for one hour at 5 MPa [at 170] pressuredegrees]C.
Laminated samples are used to test PET film degradation by measuring the force required by the piston to penetrate the surface of the film at a constant speed of 5mm per minute, as shown in Figure 1a.
The stress patterns observed during penetration are shown in Figure 1b.
When the piston contacts the PET film at point A and then penetrates into the film, the stress increases to zero to maximum B when the film breaks.
This maximum represents the residual strength of the PET film and will measure the degradation of the film during aging.
The remaining strength of the PET film after aging is shown in Figure 1c.
By changing the over-curing time of the laminate, an indication of degradation of the PET film at aging or extended mileage can be drawn.
The technology is used to measure the difference of several RFL adhesives in the protection capacity of PET film.
The stress at point B is determined to be \"PET film strength\" and is a parameter used to indicate the degree of degradation of the polyester film, as well as the ability of the adhesive to protect the film during the simulated use.
Bonding testpull adhesion -
Dip the Polyester Tire line into the RFL solution and dry for two minutes at 140 [degrees]
C and 235 [heat treatment for two minutesdegrees]C.
This provides an RFL adhesive that adheres to the wire, the coating of which is equal to 6% of the weight of the wire.
Using the rubber compound shown in Table 2, the adhesive strength is measured by the JIS 1017 method.
Sample at 150 [curing for 30 minutesdegrees]
C is the original adhesion, curing at 170 for 90 minutes [degrees]
C simulate prolonged adhesion after use.
Adhesive peel test
Samples were prepared using the compounds in table 2 and the polyester rope samples treated with RFL.
After curing, the Peel bonding strength between the wire and the rubber was determined.
Analysis of emulsion quantitative analysis of amino groups and bonding groups on the surface of latex-
Place the latex in a cellulose tube, dialysis with tap water for seven days, and adjust the pH to 2 using 0.
5N HC1 aqueous solution.
As a result, the total amount of solids is reduced to about 2%.
50 ml of this solution is used for conductivity titration using 0.
Then each functional group of the latex surface is measured (ref. 4).
Degradation mechanism of polyester after extended mileage of amine compounds-
The degradation reaction of amine compounds to hydrolysis polyester at high temperature was previously reported (ref. 2).
The molecular weight of polyester with amine compound hydrolysis was determined and used as a measurement of the degree of degradation of polyester.
In order to determine the degradation of polyester by Amine contained in rubber, PET film strength measurement methods laminated with PET film, RFL adhesive and rubber compound were used.
Several types of accelerators are used in rubber compounds in table 2, and this method is used to observe their effects on the degradation of the adhesion of polyester films.
The results are shown in figure 2.
The degree of degradation varies greatly depending on the type of accelerator used, for example, there is less degradation of PET by azoles.
Since the choice of accelerator is mainly due to its effect on the performance of tire rubber, it is also difficult to choose the accelerator with the least impact on polyester degradation.
Therefore, the rubber compound in table 2 is used for further study of tire rope bonding.
After extending the mileage, increase the adhesion of Polyester Tire rope, as a method to increase the adhesion of Polyester Tire rope after extending the mileage, developed a function to prevent the penetration of amine compounds into polyester
A three-poly vinyl ammonia-butadiene-
Styrene is a conventional latex used for the adhesive of RFL tire cord (ref. 5).
Studies have been carried out on this basic latex, introducing functional groups that react with amine compounds, thus preventing them from migrating to polyester.
It was found that functional bases such as Ester, aldehyde, and Carbo compounds are effective, but this article is limited to the study of a carbonated vinyl pyrazinebutadiene-
Three Poly benzene (ref. 3).
Properties of latex-
A conductivity titration method for analyzing the functional groups on the surface of the latex confirms the unsaturated aldehyde vinyl pyrazine-butadiene-
Three Poly benzene (ref. 4)
, As shown in Table 3.
This further confirms this, as in the traditional vinyl benzamine-butadiene-styrene latex.
Figure 3 shows the concept of the improved latex and the structure of the traditional vinyl lianamine latex.
Network effects of Carboxylic and networking
Since the improved latex has both aromatic and pyrazic bases, a network structure consisting of hydrogen bonds caused by these two functional bases can be formed.
The schematic diagram of the cross-linked network structure is shown in figure 4.
On the other hand, the traditional vinylpyridine latex has less cross-linking due to the lack of an aldehyde base.
Figure 5 shows the difference in the degree of cross-linking of carbonated vinyl benzamine latex (figure 5a)
And traditional vinyl pyridine latex (figure 5b).
Compared with the traditional vinyl-linked amine emulsion, the carbonated vinyl-linked amine emulsion has more cross-links and is expected to have a greater amine penetration protection capability.
Improved polyester protection of LaTeX
Figure 6 shows the ability of the improved latex and the traditional vinyl benzamine latex to protect the PET film from amine degradation.
It is clear that the improved LaTeX provides better protection.
Improve the over-curing bonding of LaTeX
Using improved latex and traditional vinyl pyrazine latex, the adhesion of Polyester Tire Cord to rubber is determined by T-
Tension test in figure 7, stripping test in figure 8.
Improved latex overcured indicates a T-of about 20% cm high adhesion than conventional latex overcured-pull test.
The peel test showed that the improved latex doubled the performance of the conventional latex and failed in the rubber layer, indicating the perfect adhesion.
Mechanism of improvement of Carboxyl-modified vinyl benzamine emulsion-
The mechanism by which the Polyester Tire Cord is improved to rubber is shown in Figure 9.
Polyester Tire Cord treated with adhesive is covered with rubber.
Polyester and adhesives are bonded by treatment with reagents such as chloro compounds or epoxy resins.
The adhesive and rubber are bonded by forming a cross-linking between the latex polymer and the unsaturated adhesive contained in the rubber polymer.
When the tire runs under harsh conditions, heat is generated, and the accelerator (
Migration through the adhesive layer, but interrupted by improved latex.
Therefore, although amine can penetrate and reach the polyester layer, high adhesion is maintained in the case of ordinary systems using traditional vinylpyridine latex.
Conclusion compared with the traditional vinyl benzene emulsion, the carbonated vinyl benzene emulsion has a better adhesion to extend the mileage Polyester Tire Cord, so it is now used in heavy truck and bus tires.
Studies on the mechanism of increasing adhesion after extending mileage with improved carbonated latex show that * aromatic free radicals react with amine to prevent them from penetrating the polyester line.
* Amine compounds are also prevented from penetrating the adhesive layer, although the aroma of the latex polymer and the network structure of the piryl radical can cause obstacles. [
Figure 1-9 omitted][
Table data omitted from 1 to 3]References (1)
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