JPH03255246A - Processing of canvas for belt - Google Patents

Abstract

PURPOSE:To improve the mechanical properties, heat resistance and adhesion by coating canvas for a belt with an RFL(resolsin-formalin-latex) composition of which an L(latex) component includes H-NBR (acrylonitrile-butadiene rubber hydride), and specifying an R/F mole ratio of the RFL composition and a weight ratio of RF/L solid content respectively. CONSTITUTION:An RFL composition is regulated by adding an L(latex) component including H-NBR (acrylonitrile-butadiene rubber hydride) to an RF (resorcin-formalin condensate) liquid prepared in advance. It is preferable that an R/F mole ratio is 1:1-5 and weight ratio of an RF/L solid content is 1:4-20 respectively and pH concentration of the RFL composition is regulated to approximate 10-11. A dipping process is applied to base cloth made of nylon-6 or nylon-66 or the like by using this composition while the quantity to be stuck is controlled by a solid content ratio of an RFL- processing liquid and a clearance amount of drawing rolls in the dipping process so as to keep at 10 to 50weight% to the base cloth, and the base cloth is dried at approximate 110 deg.C and further heat-treated at approximate 220 deg.C to obtain a canvas 14. As a result, mechanical property, heat-resisting property of the canvas 14 and adhesive property between the canvas and the acrylonitrile-butadiene rubber hydride which are the weakest points for the canvas are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for treating canvas that forms part of a belt and is used to reinforce the belt.

[Prior art] In the past, chloroprene rubber was mainly used for belts such as toothed belts, Heat resistance etc. are increasing.

Therefore, in place of conventional chloroprene rubber belts, materials that can meet the above requirements, such as hydrogenated nitrile rubber (H-NBR), have been put into practical use, and belt canvases using this hydrogenated nitrile rubber have been developed. As before, rubber glue was used for the treatment.

[Problem to be solved by the invention]

However, bells with canvas treated with the above conventional techniques)
(11) (see Figure 1) is hydrogenated nitrile rubber (1
2), and even if the glass fiber cord (13) meets the new performance requirements, the belt canvas (14) cannot meet the new performance requirements, and during the use of the belt (11), the canvas (14) may develop cracks, etc. There was a problem in that this resulted in damage to the belt (11).

That is, when analyzing the damage status of the belt (11) for a toothed belt used as a timing belt in an automobile engine, ■First, the tooth root part (15) of the canvas (14) covering the surface of the belt (11) ) cracks occur from ■
Next, the tooth (16) of the bell l-(11) itself was damaged.
In most cases, the belt (11) eventually breaks.
Therefore, the weakest point of the belt (If) is its canvas (14
), and canvas (14) is considered to be the weak point for belts and flat belts as well.

That is, it is considered that the elastic properties of the canvas (14) in a thermal environment (mechanical properties such as adhesion, abrasion resistance, bending fatigue resistance, and canvas strength) are important.

Therefore, this invention was made in view of the above-mentioned circumstances, and its purpose is to improve the mechanical properties, heat resistance, and Another object of the present invention is to provide a method for treating belt canvas that can improve the adhesion between the canvas and hydrogenated nitrile rubber.

[Means to solve the problem]

In order to achieve the above objectives, we have taken the following technical measures to provide a processing method for belt canvas in order to obtain canvas with well-balanced mechanical properties, heat resistance, and adhesive properties. .

That is, the present invention provides H-N to the latex component.
This method is characterized by treating canvas with an RFL composition containing BR (hydrogenated nitrile rubber).

As the L component, carboxylated NBR latex, chlorosulfonated polyethylene latex, H-NBR latex, vinylpyridine-styrene butadiene latex, etc. can be considered, but among these, H-NBR is the best as will be detailed later. The results were obtained.

A base fabric is coated with the RFL composition having H-NBR as the L component. The amount of the composition adhered to the base fabric is preferably 10 to 50% by weight, more preferably 20 to 30% by weight based on the weight of the base fabric. Here, the base fabric is RFL
The treated fabric is canvas, and the base fabric is the fabric before RFL treatment.

The amount of adhesion is controlled by the solid content ratio of the RFL treatment liquid and the amount of gap between squeezing rolls during dip treatment. here,
When the adhesion amount is less than 10% by weight, the adhesion between the canvas and rubber or the abrasion resistance of the canvas decreases, and when it exceeds 50% by weight, the mechanical properties and flexibility of the canvas decrease.

〔Example〕

Examples of the present invention are shown below.

In the following description, unless otherwise specified, numerical values are based on weight.

(1) First, an RF liquid is prepared, and an RFL&Il composition is prepared using a latex containing H-NBR (hydrogenated nitrile rubber) as an L (latex) component.

(a) Preparation of RF liquid The R/F molar ratio is preferably 1:1 to 5, more preferably 1:1 to 2, and the RF liquid was prepared at the ratio shown below.

Resorcinol... 17.3g formalin (
35%)...13°Water...340°NaOH aqueous solution (10%)・3°(Total・
...374° etc.) The adjusted RF/L solid content weight ratio of the RF L composition is preferably 1:4 to 20, more preferably 1:5 to 10, and the ratio shown below is ρ) 110 to The RFL composition was prepared in such a manner that the number of RFLs was 11.

Said RF liquid...374.7g water chlorine (L)...556.0g ammonia water (
28%)... 10.0g water
...282.6g (total...
1223.2g) Zetpol 2020 latex from Nippon Zeon ■ was used as the *latex (L).

(c) Coating the base fabric with the RFL composition Using the RFL composition described above, a base fabric made of nylon 6, nylon 66, etc. 7g) The amount of adhesion is 30% of the weight of the base fabric based on the gap between re-rolls.
A dip treatment was performed while controlling the weight %, followed by drying at 110°C and further heat treatment at 220°C to obtain a treated canvas.

(2) Evaluation Tests Various tests were carried out as described below using the canvas produced as described above or a belt produced using this canvas in the following manner.

In the tables and figures showing the results, the results of the Examples are indicated by (1).

[Preparation of Belt] A timing belt was prepared by a known method using the following rubber compound.

(Blending ratio of hydrogenated nitrile rubber) *Hydrogenated nitrile rubber...100 parts ZnO...
5.0 parts carbon blank... 40.1 stearic acid
... 1.0 part plasticizer ...
10 parts Antioxidant...2.0 parts Sulfur...0. 5 parts accelerator (T
T) ... 2.0 parts accelerator (M)
・・・ 0.5 copies (total ・・・1
61.0 parts) Zetpol 2020 from Nippon Zeon ■ was used as the *hydrogenated nitrile rubber.

In addition, as Comparative Examples (2) to (4), carboxylated NBR latex (2L chlorosulfonated polyethylene latex (3L vinylpyridine-styrene butadiene latex (4)) was used as the L (latex) component, and RF
L composition was prepared. Examples of formulations are shown in the table on the next page.

(Hereinafter, blank space) In addition, as another comparative example (5), a rubber mixture blended in the ratio shown below was dissolved in 2.0 to 3.5 times the amount of solvent, and then phenol resin was added at 20 to 35 times the amount of the rubber mixture. A processing agent was prepared by adding and dissolving % of the rubber paste.

(Blending ratio of rubber mixture) *Hydrogenated nitrile rubber...100 parts ZnO...
5.0 parts carbon black... 40.0 parts stearic acid
... 1.0 part anti-aging agent ...
2.0 parts sulfur... 0.5 parts accelerator (TT)... 2.0 parts accelerator (CZ)
... 1.0 copies (total...1
51.5 parts) Zetpol 2020 from Nippon Zeon ■ was used as the *hydrogenated nitrile rubber.

■ Peeling test on adhesive strength between canvas and the above rubber A. Peeling test at room temperature A sample was prepared by pressure-vulcanizing canvas on hydrogenated nitrile rubber, and a peeling test was conducted between the canvas and hydrogenated nitrile rubber at room temperature to determine the adhesive strength. It was measured.

(Test conditions: tensile speed 50vn/lll1n) As is clear from the results shown in the table below (page 16), the adhesive strength between the canvas of this invention and hydrogenated nitrile rubber was higher than that of the conventional RFL composition. It is very strong compared to others.

Peeling test to examine thermal deterioration over time at 0.120"C for a certain period of time The width of the belt was adjusted to 19.1 mm, and the belt was left in a gear oven at 120°C for a specified period of time, and the bottom of the belt teeth after thermal deterioration over time A peel test was conducted at room temperature to measure the adhesive strength.The results are shown in Figure 2.

(Test conditions; tensile speed 50 mm/min) C, 10
Peeling test to examine thermal deterioration over time in an oil atmosphere at 0°C at regular intervals The width of the belt was adjusted to 19.1 mm, and the belt was immersed in oil at about 100°C. A peel test was conducted on the canvas at room temperature to measure the adhesive strength. The results are shown in Figure 3.

Peeling test to examine thermal deterioration over time in a spring water atmosphere at 100°C at regular intervals The width of the belt was adjusted to 19.1 mm, and the belt was immersed in water at about 100°C, and the belt teeth were removed at regular intervals. A peel test was conducted on the bottom at room temperature to measure the adhesive strength. The results are shown in Figure 4.

From these Figures 2 to 4, it can be seen that the above adhesive strength is at 120°C.
It is clear that the adhesive strength due to thermal deterioration over time at 100° C., oil resistance deterioration over time at 100° C., and fresh water thermal deterioration over time maintains a higher value than the conventional one. That is, it can be said that the canvas according to the present invention is suitable even under conditions where the canvas is exposed to oil or steam at high temperatures.

Furthermore, the initial adhesive strength is particularly excellent in any of the above graphs. In this way, the belt and the member it engages with are not yet familiar with each other, and unreasonable force tends to be applied.If the adhesive strength of the heald is excellent during initial operation (so-called break-in operation), deterioration during this period may occur. is minimal,
After this, the durability of the belt is particularly affected by the outer rod.

Tensile test to examine the thermal deterioration of the mechanical strength of canvas over time at 0120°C for a certain period of time The width of the canvas was set to 25 mm, and the canvas alone was tested at 150°C x 2.
Press vulcanization treatment was performed for 0 minutes, and the canvas was left in an oven at 120 ° C for a predetermined period of time, and after thermal deterioration over time, a tensile test was conducted in the stretching direction of the canvas at room temperature, and its breaking strength was measured.
The rate of thermal deterioration over time was calculated by comparison with the initial value.

(Test conditions: tensile speed 200 mm/1 Ilin) From the results shown in FIG. 5, it can be seen that the rate of thermal deterioration of mechanical strength at high temperatures (120° C.) is also excellent compared to conventional canvas.

■Abrasion resistance test A: Taber type abrasion resistance test at room temperature 1 for canvas alone
A wear test was conducted using a sample that had been press-vulcanized at 50°C for 20 minutes using a Teba wear test machine (model 5150). Note that the evaluation was based on abrasion weight (loss weight).

(Test conditions: load 500g, wear wheel H-18, rotation speed 4,000 rotations) The results are shown in FIG. 6.

Wear resistance test by changing thickness at regular intervals in a humid heat atmosphere at 100°C The belt was passed over a pair of pulleys, and a running test was conducted in a tank where water was boiling at the bottom.

The evaluation was based on the degree of decrease in the thickness of the canvas at the bottom of the belt teeth after running. The results are shown in FIG.

From the results shown in Figures 6 and 7, the wear resistance at room temperature, 1
It can be seen that both wear characteristics over time in a 00°C wet heat atmosphere are superior to belts using conventional canvas.

■Using a 140'C bending fatigue durability test belt,
At an ambient temperature of 140° C., a bending test was conducted on the fabric at the base of the belt using a Dema-Cha bending tester (model: FT-202 [Special]: ■ manufactured by Shinju Seisakusho). The evaluation was based on the number of times cracks occurred in the fabric at the base of the belt, extending through the entire thickness of the fabric.

(Test conditions: Number of bending times: 300 times per minute [one reciprocating motion is counted as one time]; Maximum distance between sample gripping chucks: 75 mm, minimum: 19 mm) The results are as shown in Figure 8. The durability of the belt used is clearly superior to conventional belts.

■ Running test The following two types of running tests were conducted using the above-mentioned timing belt. The running life was determined by the time it took for cracks to occur in the canvas at the root of the belt, which covered the entire thickness of the fabric.

B. Heat-resistant running test at 110°C The belt was passed between a pair of pulleys at an ambient temperature of 110°C, and the crack life of the canvas at the base of the belt teeth was evaluated based on the crack initiation time.

End Durability Test at Root of Teeth at 80°C The belt was passed between three pulleys under an ambient temperature of 80°C, and the crack life of the canvas at the root of the belt was evaluated based on the crack generation time.

From the results shown in the table below, it can be seen that the durability under high temperature operation is much lower than that of conventional belts.

The test results for ■-I, ■-I, and mouth mentioned above are shown in the following table.

*■-I...Peeling test unit at room temperature; (Kgf/25mm) *■-I...Heat-resistant running test running life at 110°C; (hours [H]) *■-mouth...80゛Tooth base durability test running life at C; (time [H]) *1... (Rubber destruction) *2... (Partial rubber destruction) [Effects of the invention] By the processing method for belt canvas of this invention As is clear from the test results shown in the table and figure, belts made from treated canvas have poor mechanical properties, heat resistance, and adhesion between the canvas and hydrogenated nitrile rubber, which are the belt's weakest points. It has the effect of improving sex.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a cross-sectional state of a toothed belt having a canvas processed by the belt canvas processing method according to the present invention. Figure 2 is a graph showing the results of a peel test regarding heat aging of adhesive strength at 120°C;
Figure 4 is a graph showing the results of a peel test regarding heat aging of adhesive strength in an oil atmosphere at 100°C; , a graph showing the results of a tensile test regarding heat aging of mechanical properties at 120°C, and FIG. 6 is a graph showing the results of a test regarding abrasion resistance at room temperature. Figure 7 is a graph showing the results of a wear resistance test in a fresh water atmosphere at 100°C.
It is a graph showing the results of a durability test regarding bending fatigue at 0°C.

Claims (1)

[Scope of Claims] 1. A method for treating belt canvas, which comprises coating the belt canvas with an RFL composition containing H-NBR as the L component. 2. The R/F molar ratio of the RFL composition is 1:1 to 5, R
2. The method for treating belt canvas according to claim 1, wherein the F/L solid content weight ratio is 1:4 to 20. 3. The method for treating a belt canvas according to claim 1 or 2, wherein the amount of the RFL composition deposited on the canvas is about 10 to 50% by weight based on the weight of the base fabric.