JPH08270735A - Belt - Google Patents

Abstract

PURPOSE: To improve mechanical characteristic, heat resistance of a canvas and adhesion with the canvas and nitrile hydroxide rubber and provide a belt which has improved adhesion with the canvas and the rubber, abrasion resistance of the canvas, excellent in mechanical characteristic and bending property of the canvas. CONSTITUTION: A belt 11 is mainly composed of nitrile hydroxide rubber and which has canvas 15 coated with a resorcinol.formalin.latex composition and the resorcinol.formalin.latex composition contains nitrile hydroxide rubber in its latex component and adhering amount of the resorcinol.formalin.latex composition to the canvas 15 is about 10-50weight% with respect to weight of ground fabric.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt such as a timing belt for automobiles, or a toothed belt used for carrying a carrier such as a copier or a printer.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 1 to 3, chloroprene rubber is mainly used for belts (11), V belts (12), belts (11) and (12) such as flat belts. The structure is composed of a rubber (13), a tensile member (14) such as glass fiber cord for rubber reinforcement, and a reinforcing canvas (15) used on the surface or inside of the belt.

By the way, in recent years, the performance required for a belt has been increasing in various fields. For example, in the fields of the automobile industry and the like, as the output of the engine has increased due to technological advances, the belt is now being subjected to a higher load than ever before, and mechanical properties superior to those of conventional belts are required. It's starting to happen. Further, since the temperature near the belt in the engine room is also rising, higher heat resistance has been required.

Therefore, in place of the conventional chloroprene rubber belt, a material that can meet the above requirements, such as hydrogenated nitrile rubber (H-NBR), has been put into practical use. In the OA equipment industry, the situation is similar to the above. In response to these trends in the industrial world, proposals have been made regarding tensile members such as glass fiber cords for reinforcing hydrogenated nitrile rubber (Japanese Patent Laid-Open No. 63-270877).
The tensile body such as the glass fiber cord of this publication brings about an improvement in the adhesiveness with the hydrogenated nitrile rubber.

However, in the above conventional technique, even if the hydrogenated nitrile rubber or the glass fiber cord described in the above publication satisfies the new required performance, the reinforcing fabric of the belt cannot satisfy the performance, and the belt is in use. However, there has been a problem in that the canvas is cracked and the belt is damaged.

That is, when the broken state of the belt is analyzed with respect to the toothed belt used as a timing belt in an automobile engine (see FIGS. 1 and 2), first, the canvas (15) covering the surface of the belt (11) is detected. ) Root of root (16)
Most often leads to damage to the belt (11), which in turn leads to damage to the teeth (17) of the belt (11), and thus the weakest point of the belt (11) is its canvas. It is considered that the V-belt (12) and the flat belt are also the weak points of the canvas (15). That is, it is considered that the various properties (adhesiveness, abrasion resistance, bending fatigue property, mechanical properties such as the strength of the canvas) of the canvas (15) under the thermal environment are important.

[0007]

Therefore, the present invention has been made in view of the above circumstances, and its purpose is to provide the belt with the most weak points, namely, the mechanical properties of the canvas and the heat resistance. The present invention aims to provide a belt having improved properties, adhesiveness between sail cloth and hydrogenated nitrile rubber, and particularly excellent adhesion between sail cloth and rubber, abrasion resistance of sail cloth, mechanical characteristics of sail cloth, and flexibility.

[0008]

In order to achieve the above objects, the following technical means were taken in order to obtain a canvas in which mechanical properties, heat resistance and adhesiveness are well balanced.

That is, the present invention is a belt mainly composed of hydrogenated nitrile rubber, which has a canvas covered with a resorcin / formalin / latex composition,
The resorcin / formalin / latex (hereinafter, appropriately,
The composition (RFL) contains hydrogenated nitrile rubber (hereinafter appropriately abbreviated as H-NBR) in its latex component (hereinafter appropriately referred to as L component), and the resorcinol-formalin composition to be applied to the canvas. -The amount of the latex composition deposited is about 10 to 50% by weight with respect to the weight of the base fabric.

As the L component, carboxylated NBR latex, chlorosulfonated polyethylene latex,
H-NBR latex, vinyl pyridine-styrene butadiene latex and the like are considered, among which H-N
The BR gave the best results as detailed below.

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

The amount of adhesion is controlled by the ratio of the solid content of the RFL processing liquid and the gap amount of the squeezing roll during dip processing. Here, if the adhesion amount is less than 10% by weight, the adhesiveness between the canvas and the rubber or the abrasion resistance of the canvas decreases,
On the other hand, if the content is more than 10% by weight, the mechanical properties and flexibility of the canvas will deteriorate.

A belt is prepared by a known method using the above-mentioned canvas.

[0014]

EXAMPLES Examples of the present invention will be shown below.

In the following description, numerical values are based on weight unless otherwise specified. (1) First, an RFL composition containing H-NBR (hydrogenated nitrile rubber) in the L (latex) component is prepared.

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

Resorcin ... 17.3 g Formalin (35%) ... 13.2 g Water ... 340.5 g NaOH aqueous solution (10%) ... 3.7 g (total ... 374.7 g) (b) Preparation of RFL composition RF / L The solid content weight ratio is preferably 1: 4 to 20, more preferably 1: 5 to 10, and the RFL composition was adjusted so that the pH was 10 to 11 at the ratios shown below.

The RF liquid: 374.7 g * latex (L): 556.0 g Ammonia water (28%): 10.0 g Water: 282.6 g (total: 1223.3 g) The * latex (L) is Japan. Zetpol from Zeon
2020 latex was used.

(C) Coating of base fabric with RFL composition Using the RFL treatment liquid, a base fabric made of nylon 6 or nylon 66 is squeezed by a ratio of solid content of the RFL treatment liquid and a squeezing roll at the time of dip treatment. The dipped treatment is performed by controlling the amount of adhesion to be 30% by weight with respect to the weight of the base cloth by the amount of the gap, then dried at 110 ° C and further heat-treated at 220 ° C to coat the canvas. Got

(D) Preparation of Belt A timing belt was prepared by a known method using the following rubber compounds.

(Blending ratio of hydrogenated nitrile rubber) * Hydrogenated nitrile rubber: 100 parts ZnO: 5.0 parts Carbon black: 40.0 parts Stearic acid: 1.0 parts Plasticizer: 10 parts Anti-aging agent: 2 .0 parts Sulfur ... 0.5 parts Accelerator (TT) ... 2.0 parts Accelerator (M) ... 0.5 parts (total ... 161.0 parts) As * hydrogenated nitrile rubber, Zetp of Nippon Zeon Co., Ltd.
ol 2020 was used. (2) Evaluation test The following various tests were carried out using the canvas or belt prepared as described above. The results of the examples are shown in (1) in the table and the figures showing the results.

As comparative examples (2) to (4), L
An RFL composition was prepared using carboxylated NBR latex (2), chlorosulfonated polyethylene latex (3) and vinylpyridine-styrene butadiene latex (4) as the (latex) component. Formulation example
Shown in

Further, as another comparative example (5), a rubber mixture compounded in the following ratio was dissolved in a solvent of 2.0 to 3.5 times its ratio, and then phenol resin was added to 20 parts of the rubber mixture.
About 35% was added and dissolved to prepare a rubber paste, which was prepared as a treating agent.

(Rubber mixture compounding ratio) * Hydrogenated nitrile rubber ... 100 parts ZnO ... 5.0 parts Carbon black ... 40.0 parts Stearic acid ... 1.0 parts Anti-aging agent ... 2.0 parts Sulfur ... 5 parts Accelerator (TT) ... 2.0 parts Accelerator (CZ) ... 1.0 parts (total ... 151.5 parts) As * hydrogenated nitrile rubber, Zetp of Zeon Corporation
ol 2020 was used. Peeling test on adhesive strength between canvas and hydrogenated nitrile rubber a. Peeling test at normal temperature A sample was prepared by pressing and vulcanizing canvas on hydrogenated nitrile rubber, and a peeling test between canvas and hydrogenated nitrile rubber was carried out at room temperature to measure the adhesive strength (test condition; tensile speed 50 mm /
min).

As is clear from the results shown in Table 2, the adhesive strength between the canvas and the hydrogenated nitrile rubber according to this example is much stronger than that of the belt using the conventional RFL composition. is there.

B. Peeling test for examining heat deterioration at 120 ° C. for a certain period of time The width of the belt is made uniform to 19.1 mm and left for a predetermined time during gear opening at 120 ° C. to perform a peeling test of the bottom portion of the belt after heat deterioration. It performed at normal temperature and measured the adhesive strength. The results are shown in Fig. 4 (test conditions; tensile speed 50 mm /
min).

C. Peeling test to examine heat deterioration with time at 100 ° C in an oil atmosphere at regular intervals The width of the belt is adjusted to 19.1 mm, the belt is immersed in oil at about 100 ° C, and the root portion of the belt is peeled at regular intervals. The test was conducted at room temperature and the adhesive strength was measured. The result is shown in FIG.
Shown in

D. Peeling test for examining heat deterioration with time at 100 ° C under boiling water atmosphere Aligning the width of the belt to 19.1 mm, immersing the belt in water at about 100 ° C, and removing the belt bottom of the belt at regular intervals. The peeling test was performed at room temperature to measure the adhesive strength. The result is shown in Fig. 6.
Shown in

From these FIG. 4 to FIG.
It is clear that the adhesive strength due to the heat deterioration at 20 ° C., the oil heat resistance deterioration at 100 ° C. and the boiling water heat deterioration at 100 ° C. is higher than the conventional one. That is,
It can be said that the belt according to this embodiment is suitable even under the condition of being exposed to oil or steam at high temperature.

Further, in any of the above graphs, the initial adhesive strength is particularly excellent. In this way, the initial operation (so-called running-in operation) in which the belt and the member with which the belt is engaged are still less familiar and tend to be applied with unreasonable force
Sometimes, if the belt has good adhesive strength, the deterioration at this time is minimized, and the durability of the belt after that is especially,
Have a positive effect. Tensile test for investigating the rate of thermal deterioration of mechanical strength of canvas at 120 ° C for a certain period of time Aligning the width of the canvas to 25 mm, the canvas alone is press vulcanized at 150 ° C for 20 minutes, and then in an oven at 120 ° C. The fabric was left to stand for a predetermined period of time, and a tensile test in the stretching direction of the canvas after heat deterioration was performed at room temperature, the breaking strength was measured, and the ratio of heat deterioration with time was calculated by comparison with the initial value (test condition: tensile strength). Speed 200 mm / min).

From the results shown in FIG. 7, high temperature (120 ° C.)
It can be seen that the rate of thermal deterioration of mechanical strength below is also superior to that of conventional canvas. Abrasion resistance test a. Taber-type abrasion resistance test at room temperature Using a sample that has been subjected to press vulcanization treatment with a canvas alone at 150 ° C for 20 minutes, a Taber abrasion tester (model 5150)
A wear test was performed using The evaluation was based on the wear weight (loss weight) (test conditions; load 500 g, wear wheel H-18, rotation speed 4,000 rotations). The results are shown in Fig. 8.

B. Abrasion resistance test by changing thickness at constant time under 100 ° C. moist heat atmosphere A belt was laid over a pair of pulleys, and a running test was conducted in a tank in which water was boiled at the bottom. The evaluation was based on the degree of decrease in the thickness of the belt bottom canvas after running. The results are shown in Fig. 9.

From the results of FIGS. 8 and 9, it can be seen that both the wear resistance at room temperature and the deterioration with time of the wear characteristics in a 100 ° C. moist heat atmosphere are superior to those of the conventional belt. Endurance test by bending fatigue at 140 ° C Using a belt, using a DeMatcha bending tester (model; FT-202 [special]: manufactured by Ueshima Seisakusho) at an ambient temperature of 140 ° C, a bending test of canvas at the root of the belt I went. The evaluation was based on the number of times that cracks were formed on the canvas at the root portion of the belt over the entire cloth thickness. (Test conditions: Number of flexes 300 times per minute [1 reciprocating motion 1
Let's do it. ]; Distance between gripping chucks of sample, maximum 7
(5 mm, minimum 19 mm) As a result, as shown in FIG. 10, the durability of the belt according to this example is clearly superior to that of the conventional belt. Running Test The following two types of running tests were performed using the timing belt. The running life was determined by the crack generation time over the entire thickness of the canvas at the root of the belt.

A. Heat-resistant running test at 110 ° C. The belt was stretched between a pair of pulleys at an ambient temperature of 110 ° C., and the crack life of the canvas at the root of the belt was evaluated by the crack generation time.

B. Root durability test at 80 ° C. The belt was stretched between three pulleys at an ambient temperature of 80 ° C. and the crack life of the belt root canvas was evaluated by the crack generation time.

From the results shown in Table 2, it can be seen that the durability under high temperature operation is extremely superior to that of the conventional belt.

Table 2 shows the test results of the above-mentioned a, b, and b.

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

EFFECTS OF THE INVENTION The belt of the present invention has the above-mentioned constitution, and as is clear from the test results shown in the tables and figures, the belt has the most weak points, namely, the mechanical properties of the canvas, the heat resistance, and the Improves adhesion with hydrogenated nitrile rubber,
In particular, there is an effect that it is possible to provide a belt having excellent adhesiveness between canvas and rubber, abrasion resistance of canvas, mechanical properties of canvas, and flexibility.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a belt according to the present invention and showing a sectional state of a toothed belt.

FIG. 2 is a perspective view showing an embodiment of the belt according to the present invention and showing a sectional state of the toothed belt.

FIG. 3 is a perspective view showing a cross section of a V-belt showing an embodiment of a belt according to the present invention.

FIG. 4 is a graph showing the results of a peel test on heat aging of adhesiveness at 120 ° C.

FIG. 5 is a graph showing the results of a peeling test regarding heat aging of adhesiveness in an oil atmosphere at 100 ° C.

FIG. 6 is a graph showing the results of a peeling test on heat aging of adhesiveness in a boiling water atmosphere at 100 ° C.

FIG. 7 is a graph showing the results of a tensile test on the rate of thermal deterioration of mechanical properties at 120 ° C.

FIG. 8 is a graph showing the results of tests on wear resistance at room temperature.

FIG. 9 is a graph showing the results of a durability test on wear resistance in a boiling water atmosphere at 100 ° C.

FIG. 10 is a graph showing the results of a durability test regarding bending fatigue at 140 ° C.

[Explanation of symbols]

 11 belt 12 belt 15 canvas

Claims (1)

[Claims] 1. A belt mainly composed of hydrogenated nitrile rubber, comprising a canvas covered with a resorcinol-formalin latex composition, wherein the resorcinol-formalin latex composition is hydrogenated to its latex component. A belt containing nitrile rubber, wherein the amount of the resorcinol-formalin latex composition deposited on the canvas is about 10 to 50% by weight based on the weight of the base fabric.