JPH071052B2 - belt - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a timing belt for an automobile or a belt such as a toothed belt used for carrying a carrier such as a copier or a printer.

[Prior Art] Conventionally, as shown in FIGS. 1 to 3, a toothed belt (1
1), V-belts (12), flat belts and other belts (11) (1
Chloroprene rubber is mainly used for 2), and its constitution is rubber (13), tensile body (14) such as glass fiber cord for rubber reinforcement, reinforcing canvas used on the surface or inside of belt. It consists of (15).

By the way, in recent years, the performance required for the 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, materials that can meet the above requirements, such as hydrogenated nitrile rubber (H-NBR), have been put to 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-mentioned conventional technique, even if the glass fiber cords of the hydrogenated nitrile rubber and the above-mentioned publication satisfy the new required performance, the belt reinforcing canvas cannot satisfy the performance,
During the use of the belt, there is a problem that the canvas is cracked and the belt is damaged.

That is, when the belt damage condition is analyzed for a toothed belt used as a timing belt in an automobile engine (see FIGS. 1 and 2), first, the belt (11)
The root part (16) of the canvas (15) covering the surface of the belt (15) may crack, and then the teeth (17) of the belt (11) may be lost, eventually leading to damage of the belt (11). Most, and therefore the weakest point of the belt (11) is its canvas (1
5), and the V-belt (12) and the flat belt are also considered to be 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.

[Problems to be Solved by the Invention]

Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to modify a treating agent (RFL composition) for a canvas, which is the most weak point of the belt. It is intended to provide a belt having improved mechanical properties, heat resistance, and adhesion between canvas and hydrogenated nitrile rubber.

[Means for Solving the Problems]

In order to achieve the above object, the following technical measures 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, having a canvas covered with a resorcinol-formalin latex composition, wherein the resorcinol-formalin latex (hereinafter appropriately referred to as RFL) The composition has hydrogenated nitrile rubber (hereinafter appropriately referred to as H-NBR) as its latex component (hereinafter appropriately referred to as L component).
Is abbreviated).

As the L component, carboxylated NBR latex, chlorosulfonated polyethylene latex, H-NBR latex, vinyl pyridine-styrene budadien latex, etc. can be considered. Among them, H-NBR has the best results as detailed later. was gotten.

The base fabric is coated with the RFL composition having H-NBR in the L component. The amount of the composition attached to the base cloth is preferably 10 to 50% by weight, more preferably 20 to 50% by weight based on the weight of the base cloth.
30% by weight. Here, the fabric subjected to RFL treatment is sailcloth, and the base fabric refers to the fabric before RFL treatment.

The amount of adhesion is controlled by the ratio of the solid content of the RFL treatment liquid and the gap amount of the squeezing roll during dip treatment. Here, when the adhesion amount is less than 10% by weight, the adhesiveness between the canvas and the rubber,
Alternatively, the abrasion resistance of the canvas decreases, and when it is 50% by weight or more, the mechanical properties and flexibility of the canvas are deteriorated.

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

〔Example〕

 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 liquid The R / F molar ratio is preferably 1: 1 to 5, more preferably 1: 1.
The RF liquid was prepared at the ratios of 1 to 2 below.

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

The RF liquid ... 374.7g * Latex (L) ... 556.0g Ammonia water (28%) ... 10.0g Water ... 282.6g (total ... 1223.3g) The * Latex (L) is Ze of Nippon Zeon Co., Ltd.
tpol 2020 latex was used.

(C) Coating of base fabric with RFL composition Using the RFL treatment liquid, nylon 6 or nylon 6
Dip treatment is performed on the base fabric consisting of 6 etc. by controlling the solid content of the RFL treatment liquid and the gap amount of the squeezing roll during dip treatment so that the adhered amount is 30% by weight relative to the weight of the base fabric. Then, it was dried at 110 ° C. and further heat-treated at 220 ° C. to obtain a coated canvas.

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

(Compounding 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, a product of Nippon Zeon Co., Ltd.
Zetpol 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.

In addition, as Comparative Examples (2) to (4), L (latex)
RF using carboxylated NBR latex (2), chlorosulfonated polyethylene latex (3) and vinyl pyridine-styrene butadiene latex (4) as components
The L composition was prepared. A formulation example is shown in the table on the next page.

Also, as another comparative example (5), a rubber mixture prepared by mixing in the following ratio was dissolved in a solvent of 2.0 to 3.5 times, and then phenol resin was added and dissolved in 20 to 35% of the rubber mixture to obtain a rubber paste. Was prepared as a treating agent.

(Ratio of rubber mixture) * 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: 0.5 parts Accelerator (TT): 2.0 parts Accelerator ( CZ) 1.0 part (total: 151.5 parts) As * hydrogenated nitrile rubber, available from Nippon Zeon Co., Ltd.
Zetpol 2020 was used.

Peeling test on adhesive strength between canvas and hydrogenated nitrile rubber a. Peeling test at room temperature A sample was prepared by press-cure vulcanizing canvas to hydrogenated nitrile rubber, and a peeling test between canvas and hydrogenated nitrile rubber was performed at room temperature to measure the adhesive strength (test condition; pulling speed 50 mm / mi
n).

As is clear from the results shown in the table below, the adhesive force between the canvas according to this example and the hydrogenated nitrile rubber was
It is much stronger than belts using the L composition.

B. Peeling test to examine heat deterioration over time at 120 ° C Align the belt width to 19.1 mm, leave it for 120 hours at 120 ° C gear open for a predetermined time, and perform a peeling test for the bottom of the belt after heat deterioration over time at room temperature. And the adhesive strength was measured. The results are shown in Fig. 4 (test conditions; pulling speed 50 mm / min).

C. Peeling test to examine heat deterioration over time in oil atmosphere at 100 ° C Aligning the width of the belt to 19.1 mm, immersing the belt in oil at about 100 ° C, and peeling test of the bottom part of the belt at regular intervals Was performed at room temperature, and the adhesive strength was measured. Results are shown in FIG.

D. Peeling test to examine thermal deterioration over time at 100 ° C under boiling water atmosphere Align the width of the belt to 19.1 mm, immerse the belt in water at about 100 ° C, and peel off the bottom of the belt at regular intervals. The test was conducted at room temperature and the adhesive strength was measured. Results are shown in FIG.

From FIGS. 4 to 6, the adhesive strength due to the above-mentioned adhesive strength due to heat deterioration at 120 ° C., oil heat resistance deterioration at 100 ° C., and boiling water heat deterioration with time has maintained higher values than conventional ones. Is clear. 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.

Furthermore, in any of the above graphs, the initial adhesive strength is particularly excellent. As described above, if the adhesive strength of the belt is excellent during the initial operation (so-called running-in operation) in which the belt and the member with which the belt engages are less familiar with each other and an unreasonable force tends to be applied, deterioration at this time is caused. Is minimal, which has a particularly positive effect on the subsequent durability of the belt.

Tensile test to examine the rate of mechanical deterioration of the mechanical strength of canvas at 120 ℃ for a certain period of time Align the width of the canvas to 25 mm, press vulcanize the canvas alone at 150 ℃ for 20 minutes, and then in an oven at 120 ℃ 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). Strength 200 mm / min).

From the results shown in FIG. 7, it can be seen that the rate of thermal deterioration of mechanical strength at high temperature (120 ° C.) is also superior to that of conventional canvas.

Abrasion resistance test a. Taber-type abrasion resistance test at room temperature A sample of the canvas was press-vulcanized at 150 ° C. for 20 minutes, and a abrasion test was performed using a abrasion tester (model 5150) manufactured by Taber. The evaluation is the wear weight (loss weight)
(Test conditions: load 500g, wear theory H-18, rotation speed
4,000 rotations). The results are shown in Fig. 8.

B. Abrasion resistance test by changing thickness at constant time in 100 ° C wet 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 Fig. 8 and Fig. 9, the wear resistance at room temperature
It can be seen that the deterioration of the wear characteristics with time in a 0 ° C wet heat atmosphere is superior to that of the conventional belt.

Endurance test by 140 ° C bending fatigue Using a belt, using a DeMatcha bending tester (model; FT-202 [special]: Ueshima Seisakusho Co., Ltd.) at an ambient temperature of 140 ° C, A bending test was performed. 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 is once.]; Sample gripping chuck distance, maximum 75 mm, minimum 19 m
m) 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.

B. 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 belt root cloth 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 to evaluate the crack life of the belt root canvas by the crack generation time.

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

The following table shows the test results of the above-mentioned a, b, and b.

* -A ... Peeling test at room temperature, unit: (kgf / 25mm) * -a ... Heat resistance running test at 110 ° C, running life;
(Time [H]) * -B ... Tooth root endurance test at 80 ° C, running life; (Time [H]) [Advantages of the Invention] The belt of the present invention has the above-mentioned configuration, and as is clear from the test results shown in the tables and figures, the mechanical weakness of the belt, which is the weakest point of the belt, heat resistance, and It has an effect that it is possible to provide an excellent belt having improved adhesiveness with hydrogenated nitrile rubber.

[Brief description of drawings]

1 to 3 show an embodiment of a belt according to the present invention, FIGS. 1 and 2 are perspective views showing a sectional state of a toothed belt, and FIG. 3 is a sectional state of a V-belt. It is a perspective view shown. FIG. 4 is a graph showing the results of a peeling test on adhesive heat aging at 120 ° C., and FIG. 5 is a graph showing the results of a peeling test on adhesive heat aging at 100 ° C. in an oil atmosphere. FIG. 7 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.
The figure is a graph showing the results of a durability test regarding bending fatigue at 140 ° C. (11) (12) …… Belt, (15) …… Canvas

Claims (2)

[Claims] 1. A belt comprising hydrogenated nitrile rubber as a main component, comprising a canvas coated with a resorcinol-formalin latex composition, wherein the resorcinol-formalin latex composition is hydrogenated to its latex component. A belt comprising nitrile rubber. 2. The amount of the resorcinol-formalin-latex composition deposited on the canvas is approximately about the weight of the base fabric.
The belt according to claim 1, which is 10 to 50% by weight.