JPH03255245A - Belt - Google Patents

Abstract

PURPOSE:To improve the mechanical properties, heat resistance of canvas and adhesion between the canvas and acrylonitrile-butadiene rubber hydride (H-NBR) by compounding H-NBR in an L(latex) component of an RFL(resorcin-formalin- latex) composition of a belt having canvas coated with the RFL composition. CONSTITUTION:In a belt 12 having canvas 15 coated with an RFL composition, H-NBR (acrylonitrile-butadiene rubber hydride) is included in an L(latex) component of the RFL composition and base cloth is coated with the RFL composition. Quantity of the composition to be stuck is of 10 to 50weight% preferably to weight of the base cloth and the base cloth is treated with the RFL to make the canvas 15. Control for the quantity to be stuck is performed by solid content ratio of an RFL-processing liquid and a clearance amount of drawing rolls in a dipping process. In such constitution, mechanical property, heat-resisting property and adhesive property between the canvas and the acrylonitrile- butadiene rubber hydride which are the weakest points of the canvas are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to belts such as timing belts for automobiles, or toothed belts used for carriage feeding in copy machines, printers, and the like.

[Conventional technology]

Conventionally, as shown in Figs. 1 to 3, a toothed bell) (
Chloroprene rubber is mainly used for belts (11) (12) such as 11), V-bell l-(12), and flat belts, and its composition consists of rubber (13), glass fiber cord for rubber reinforcement, etc. The tension body (14) is made of reinforcing canvas (15) used on the surface or inside of the belt.

Incidentally, in recent years, performance requirements for belts have been increasing in various fields.

For example, in fields such as the automobile industry, as engine output increases due to advances in technology, belts are now subject to higher loads than ever before, requiring better mechanical properties than before. It's starting to look like this.

Furthermore, since the temperature near the belt in the engine room has been rising, higher heat resistance has been required.

Therefore, instead of the conventional chloroprene rubber belt, materials that meet the above requirements, such as hydrogenated nitrile rubber (H-NBR), have been put into practical use.

Furthermore, the OA equipment industry is also in a similar situation to the above.

In response to these industrial trends, proposals have been made regarding tensile bodies such as glass fiber cords for reinforcing hydrogenated nitrile rubber (Japanese Patent Laid-Open No. 63-270877).

The tensile material such as glass fiber cord of this publication provides improved adhesion to hydrogenated nitrile rubber.

[Problem to be solved by the invention]

However, with the above conventional technology, even if the hydrogenated nitrile rubber and the glass fiber cord described in the above publication meet the new performance requirements, the reinforcing canvas for the belt cannot meet the performance requirements.
There is a problem in that during use of the belt, cracks or the like occur in the canvas, leading to damage to the belt.

That is, when we analyze the state of belt damage for toothed belts used as timing belts in automobile engines (see Figures 1 and 2), we find that:
1) The root part (16) of the canvas (15) covering the surface of
A crack occurs from the ■ then the tooth (1) of the bell) (11).
7) In most cases, the belt (11) is damaged when the belt itself is damaged. Therefore, the weakest point of the belt (11) is considered to be its canvas (15). (1
2) The same goes for the flat belt (15).
is considered to be a weakness.

That is, it is considered that the elastic properties of the canvas (15) 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 circumstances, and its purpose is to provide a canvas treatment agent (
The purpose of the present invention is to provide a belt that improves the mechanical properties of canvas, heat resistance, and adhesion between canvas and hydrogenated nitrile rubber, which are the weakest points of belts, by modifying the RFL composition.

[Means to solve the problem]

In order to achieve the above objectives, the following technical measures were taken to obtain a canvas with well-balanced mechanical properties, heat resistance, and adhesion.

That is, the present invention is characterized in that, in a belt having a canvas coated with an RFL composition, the latex component of the RFL composition contains H-NBR (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. 20 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 RF
The fabric that has undergone the L treatment is canvas, and the base fabric refers to the fabric that has not been subjected to the 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 amount of adhesion 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.

A belt is made using the above canvas by a known method.

〔Example〕

Examples of the present invention are shown below.

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

(1) First, H-NBR (
An RFL composition containing hydrogenated nitrile rubber is prepared.

(a) Preparation of RF liquid The R/F molar ratio is preferably 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%)... 13.2g water
...340.5gNa0)1 aqueous solution (10%)-3
,7g (total...374.7g
) (B) Adjustment of RFL composition The RF/L solid content weight ratio is preferably 1:4 to 2o, more preferably 1:5 to 1o, and the pH is adjusted to 10 to 11 at the ratio shown below. An RFL composition was prepared.

Said RF liquid...374.7g*Latex (L)...556.0g Ammonia water (2
8%)... 10.0g water
...282.6g (total ...1
223.3g) Zetpol 2020 latex from Nippon Zeon ■ was used as the *latex (L).

(C) Coating the base fabric with the RFL composition Using the RFL treatment liquid, a base fabric made of nylon 6, nylon 66, etc. Dip treatment was performed by controlling the amount of adhesion to be 30% by weight based on the weight of the base fabric, then drying at 110°C, and further drying at 220°C.
A coated canvas was obtained by heat treatment.

(d) 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...ioo 5ZnO-
5.0 parts Carbon black... 40.0 parts Stearic acid... 1.0 parts Plasticizer...
・10 parts anti-aging agent...2,0
Part sulfur: 0.5 part Accelerator (T
T) ... 2.0 copies promotion 荊 (M)
・・・ 0.5 copies (total ・・・1
61.0 parts) Zetpol 2020 from Nippon Zeon ■ was used as the *hydrogenated nitrile rubber.

(2) Evaluation Tests The following various tests were conducted using the canvas or belt produced as described above.

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

In addition, as comparative examples (2) to (4), L (latte, nkusu)
Carboxylated NBR latte, Nx (2) as a component,
An RFL composition was prepared using chlorosulfonated polyethylene latex (3L vinyl pyridine-styrene butadiene latex (4). 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.

■Peel test on adhesive strength between canvas and hydrogenated nitrile rubber A. Peel test at room temperature A sample was prepared by pressure-vulcanizing canvas on hydrogenated nitrile rubber, and a peel test was conducted between the canvas and hydrogenated nitrile rubber at room temperature. Adhesive strength was measured.

(Test conditions: tensile speed 50mm/l1lin) As is clear from the results shown in the table below (page 17), the adhesive strength between the canvas of this invention and hydrogenated nitrile rubber was higher than that of the conventional RFL composition. It is extremely strong compared to belts and the like.

Peeling test to examine thermal deterioration over time at 120°C for a certain period of time The width of the belt was adjusted to 19.1 mm, and the belt was left for a specified period of time while the gear was open at 120°C. A peel test was conducted at room temperature to measure the adhesive strength. The results are shown in Figure 4.

(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 approximately 100°C. A peel test was conducted at room temperature to measure the adhesive strength. The results are shown in FIG.

2. Peeling test to examine thermal deterioration over time at 100°C in a water-conducting atmosphere at regular intervals The width of the belt was adjusted to 19.1 mm, and the belt was immersed in water at approximately 100°C. A peel test was conducted on the tooth bottom at room temperature to measure the adhesive strength. The results are shown in Figure 6.

From these Figures 4 to 6, 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 water conduction heat deterioration over time maintains a higher value than the conventional one. That is, it can be said that the belt according to the present invention is suitable even under conditions where the belt is exposed to oil or steam at high temperatures.

Furthermore, in all of the above graphs, the initial adhesive strength is particularly excellent. In this way, if the adhesive strength of the belt is excellent during the initial operation (so-called break-in operation), when the belt and the members it engages are not yet familiar with each other and excessive force is likely to be applied, deterioration during this period can be avoided. This has a particularly positive effect on the subsequent durability of the belt.

Tensile test to examine the rate of thermal deterioration over time in the mechanical strength of canvas 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 performed 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 200m+m/sin) 7th
From the results shown in the figure, it can be seen that the rate of thermal deterioration of mechanical strength at high temperatures (120° C.) is also superior to that of conventional canvas.

■Abrasion resistance test A: Taber type abrasion resistance test at room temperature 1 for canvas alone
Using a sample subjected to press vulcanization treatment at 50''CX for 20 minutes, an abrasion test was conducted using an abrasion tester (Model 5150) manufactured by Teba Corporation.The evaluation was based on the abrasion weight (weight loss).

(Test conditions: load 500g, wear wheel H-18, rotation speed 4,000 rotations) The results are shown in FIG. 8.

Abrasion resistance test by changing thickness at regular intervals in a heated atmosphere of 0.100'C The belt was passed over a pair of pulleys, and a running test was conducted in a tank where water was being boiled 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 8 and 9, the wear resistance at room temperature, 1
It can be seen that both the wear characteristics and the aging deterioration in a 00°C wet heat atmosphere are superior to the conventional belt.

■ 140°C bending fatigue test using a belt, Dematcher bending tester (model, FT-202 [Special]: ■ Made by Jyuji Seisakusho) under an ambient temperature of 140°C. A bending test was conducted. 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 considered as one time]; Maximum distance between sample gripping chucks: 75 mm, minimum: 19+ am) The results are as shown in FIG. 10. The durability of the belt 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 80°C The belt was placed between three pulleys under an ambient temperature of 80°C, and the crack life of the belt dente canvas was evaluated by 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 superior to that of conventional belts.

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

*■-A...Peeling test unit at room temperature; (Kgf/25++m) ■-A...Heat-resistant running test running life at 110°C; (hours [H]) *■-Opening...80° Tooth base durability test running life at C; (time [H]) *1... (Rubber destruction) *2... (Partial rubber destruction) [Effects of the invention] The belt of this invention has the above-mentioned structure. As is clear from the test results shown in the table and figure, this is an excellent belt that improves the mechanical properties and heat resistance of the canvas, which are the weakest points of belts, as well as the adhesion between the canvas and hydrogenated nitrile rubber. It has the effect of being able to provide the following.

[Brief explanation of drawings]

1 to 3 show an embodiment of the belt according to the present invention, FIGS. 1 and 2 are perspective views showing a cross-sectional state of a toothed belt, and FIG. 3 shows a cross-sectional state of a V-belt. FIG. FIG. 4 is a graph showing the results of a peel test on heat aging of adhesives at 120"C; FIG. 5 is a graph showing the results of a peel test on heat aging of adhesives in an oil atmosphere at 100"C; Figure 6 is a graph showing the results of a peel test on heat aging of the adhesive under a hydrous atmosphere at 100'C; Figure 7 is a graph showing the results of a tensile test on the rate of thermal degradation of mechanical properties at 120'C. Graph, FIG. 8 is a graph showing the results of a test on abrasion resistance at room temperature. FIG. 9 is a graph showing the results of a durability test on abrasion resistance in a water-conducting atmosphere at 100°C. Figure 1O shows 1
It is a graph showing the results of a durability test regarding bending fatigue at 40'C.

Claims (1)

[Scope of Claims] 1. A belt having a canvas coated with an RFL composition, characterized in that the L component of the RFL composition contains H-NBR. 2. The belt according to claim 1, wherein the amount of the RFL composition adhered to the canvas is about 10 to 50% by weight based on the weight of the base fabric.