JP2010071333A - Belt, core thereof, and core treating liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt superior in oil resistance over a long period, its core and a core treating liquid. <P>SOLUTION: A sheet generated from an RFL (Resorcinol Formalin Latex) treating liquid of embodiments 1 and 2 lower in the content of latex than comparison examples 1 and 2, is smaller in a volume change in a sheet of the comparison examples 1 and 2. Thus, an RFL layer formed by the RFL treating liquid of the embodiment 1 and 2 is smaller in the volume change than the RFL layer by the RFL treating liquid of the comparison examples 1 and 2 in a state of being soaked in oil. Thus, contraction of a timing belt can be prevented by applying RFL treatment to the core by using the RFL treating liquid of the embodiments 1 and 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a belt and its core wire and a processing solution for the core wire, and more particularly to a belt used in a state where oil adheres, its core wire, and the like.

In a belt such as a timing belt, a core wire is generally embedded in order to suppress elongation and increase strength. And it is known that the core wire is treated with resorcin / formalin / latex (hereinafter referred to as RFL treatment) for the purpose of improving adhesion to the surrounding rubber layer and bending fatigue resistance (for example, Patent Document 1). ).
JP 2003-268678 A

  When the belt is used in a state where the oil adheres, the tensile strength tends to be greatly reduced as compared with the case where the belt is used in a state where the oil does not adhere. As one of the causes, it is considered that a layer (hereinafter referred to as an RFL layer) formed by RFL processing on the core of the belt is deteriorated due to oil swelling.

  Therefore, an object of the present invention is to realize a belt excellent in oil resistance over a long period of time, and a core wire and a treatment liquid for the core wire.

  The belt of the present invention includes a core wire and is used in a state where oil adheres. The core wire is treated with an RFL treatment liquid containing a rubber latex and a resorcin / formaldehyde condensate. In the RFL treatment liquid, the weight ratio of the solid content of the rubber latex to the resorcin / formaldehyde condensate is 1.4 or more. It is 2.0 or less.

  The solid content of the rubber latex is preferably 56 to 64% by weight and the solid content of the resorcin / formaldehyde condensate is preferably 32 to 40% by weight with respect to the total solid content of the RFL treatment liquid.

  The rubber latex includes, for example, acrylonitrile-butadiene rubber latex.

  The core wire of the present invention is used for a belt used in a state where oil adheres. The core wire is treated with an RFL treatment liquid containing a rubber latex and a resorcin / formaldehyde condensate, and a weight ratio of the solid content of the rubber latex to the resorcin / formaldehyde condensate is 1.4 or more and 2.0 or less. It is characterized by that.

  The RFL treatment liquid of the present invention is used for the treatment of a core wire provided in a belt used in a state where oil adheres. The RFL treatment liquid contains a rubber latex and a resorcin / formaldehyde condensate, and the weight ratio of the solid content of the rubber latex to the resorcin / formaldehyde condensate is 1.4 to 2.0.

  According to the present invention, it is possible to realize a belt excellent in oil resistance over a long period of time, and a core wire and a processing solution for the core wire.

  Hereinafter, an embodiment of a timing belt in the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a part of the timing belt according to the present embodiment in a cutaway manner. FIG. 2 is an enlarged perspective view showing the inside of the core wire included in the timing belt.

  The timing belt 10 (belt) has a tooth rubber layer 12, a canvas 18, and a back rubber layer 20. The outer surfaces of the tooth portion 14 and the tooth bottom portion 16 of the tooth rubber layer 12 are covered with a canvas 18. The canvas 18 is formed of a woven fabric made of, for example, nylon fibers. The tooth rubber layer 12 and the back rubber layer 20 are made of, for example, hydrogenated nitrile rubber.

  A plurality of core wires 30 are embedded between the tooth rubber layer 12 and the back rubber layer 20. The core wire 30 is parallel to the longitudinal direction of the timing belt 10. An adhesive rubber layer 22 having good adhesion to the core wire 30 is provided around the core wire 30, that is, between the tooth rubber layer 12 and the back rubber layer 20.

  The core wire 30 is manufactured as follows using glass fiber, for example. That is, as shown in FIG. 2, the filaments 32 that are glass fibers converge, for example, 200 pieces each to form one yarn 34. The diameter of the filament 32 is, for example, about 7 to 10 μm. The yarn 34 is immersed in an RFL (resorcin-formalin-latex) treatment solution and dried. After that, three yarns 34 are bundled and twisted in the Z direction to form one strand 36.

  The core wire 30 is formed by twisting the three strands 36 thus formed. In this upper twisting step, the strand 36 is twisted in the direction opposite to the lower twist, that is, in the S direction while applying tension to the strand 36.

  Hereinafter, the composition of the RFL treatment liquid will be described. Table 1 is a table | surface which shows the composition of the RFL process liquid of Comparative Examples 1 and 2 and Examples 1-3.

  When the timing belt 10 is used in a state where oil adheres, the strength when traveling for a long time tends to be significantly lower than when it is used in a state where no oil adheres. One possible cause is that an RFL layer (not shown) formed by the solid content of the RFL treatment liquid absorbs oil and swells and deteriorates. In particular, when the RFL layer contains a lot of latex components, it can be said that the influence of swelling due to absorption of oil is large.

  Therefore, in this embodiment, as shown in Table 1, the RFL treatment liquids of Examples 1 to 3 in which the content of acrylonitrile-butadiene rubber (NBR) latex contained in the RFL treatment liquids of Comparative Examples 1 and 2 is reduced are prepared. did. As will be described later, these RFL treatment liquids are evaluated, and a plurality of timing belts 10 in which the core wire 30 (see FIGS. 1 and 2) is treated with these RFL treatment liquids are manufactured. A comparative test was conducted.

  Each of the RFL treatment liquids of Comparative Examples 1 and 2 and Examples 1 to 3 is mainly composed of resorcin / formaldehyde water-soluble condensate (hereinafter referred to as RF) together with NBR latex, and the content of NBR latex is changed. The composition is the same except that. Since the solution of the resorcin / formaldehyde water-soluble condensate used for the preparation of each RFL treatment liquid has a solid content of 8% by weight and the NBR latex has a solid content of 40% by weight, the solid content (A) of the RF and NBR latex, (B) is the value shown in Table 1, respectively.

  In Table 1, the weight ratio B / A of the solid content (A) of RF and the solid content (B) of NBR latex shown in the bottom row, that is, the RF content of the solid content (B) of rubber latex. Except for the weight ratio B / A with respect to the solid content (A), all the units are parts by weight.

  Table 2 shows the content (%) of RF solid content (A) and NBR latex solid content (B) relative to the total solid content of the RFL treatment liquid in Comparative Examples 1 and 2 and Examples 1 to 3. It is a table.

  From the compositions of the RFL treatment liquids of Comparative Examples 1 and 2 and Examples 1 to 3 shown in Table 1, the solid content of RF (A) and the solid content of NBR latex in the total solid content of each RFL treatment liquid ( The contents of B) were calculated as shown in Table 2, respectively. As is apparent from Tables 1 and 2, the NBR latex content is low and the RF content is high in the order of Comparative Example 1, Comparative Example 2, Example 1, Example 2, and Example 3.

  In Examples 1 to 3, the weight ratio of the solid content (B) of the NBR latex to the solid content (A) of RF is in the range of 1.4 to 2.0 (see Table 1), and RFL The solid content of NBR latex is 56 to 64% by weight and the solid content of RF is 32 to 40% by weight with respect to the total solid content of the treatment liquid (see Table 2).

  Hereinafter, the evaluation test results of the RFL processing solutions of these comparative examples and examples will be described. FIG. 3 is a diagram showing the results of a hardness change test of sheets formed using the RFL treatment liquids of Comparative Examples 1 and 2 and Examples 1 and 2. FIG. 4 is a diagram showing the results of volume change tests of sheets formed using the RFL treatment liquids of Comparative Examples 1 and 2 and Examples 1 and 2.

  The same shape (20 mm in length, 40 mm in width, 2 mm in thickness) formed by drying the RFL treatment liquids of Comparative Examples 1 and 2 and Examples 1 and 2 and further curing the solid content at 150 ° C. for 20 minutes. ) Sheets were prepared. Then, one of the sheets generated from each RFL treatment liquid is immersed in oil kept at 140 ° C., and the other is left at 140 ° C. in a state where no oil adheres, and the change in hardness and volume is compared. Went.

  The hardness change test (see FIG. 3) was performed as follows. First, the initial value of the hardness of all sheets was measured using a micro rubber hardness meter MD-1 (manufactured by Kobunshi Keiki Co., Ltd.), a durometer based on the same measurement principle as JIS-A hardness. And the hardness change of each sheet | seat 24 hours and 72 hours was measured by making the initial value of the hardness of each sheet | seat into a reference | standard, ie, the hardness change rate 0%, respectively.

  From the result of this hardness change test, the hardness change rate (%) in the sheet of Example 2 is the smallest in both the state where oil does not adhere and the state where oil adheres, and then the hardness of the sheet of Example 1 It is clear that the rate of change (%) is small. And the sheet | seat of the comparative examples 1 and 2 was hardened more largely than the sheet | seat of Example 1, 2 in both the state which oil does not adhere, and the state which oil adheres.

  From the above, Examples 1 and 2 are superior in hardness stability at a higher temperature than Comparative Examples 1 and 2, and the sheet produced from the RFL treatment liquid of Example 2 is most difficult to cure. I can say that. This is considered to be due to the fact that the content of NBR latex, which is the main cause of thermosetting, is lower in the order of Example 2 and Example 1 (see Table 2).

  Note that, in any of the comparative examples and examples, the curing of the sheet is suppressed in a state where the oil adheres rather than the state where the oil does not adhere. This is because in a state where the oil adheres, the sheet is cured and swollen by the oil.

  On the other hand, the volume change test was performed as follows. That is, the initial value of the specific gravity of each sheet was measured, and the specific gravity after 24 hours and 72 hours was measured. Then, the initial value of the specific gravity of each sheet was used as a reference (volume change rate 0%), and the volume change was calculated from the change in specific gravity. The specific gravity of the sheet was measured based on JIS K6268.

  From the volume change test results (see FIG. 4), among the sheets immersed in 140 ° C. oil, Examples 1 and 2 have less volume change than Comparative Examples 1 and 2, and in particular, the RFL of Example 2 It is clear that the sheet produced from the treatment liquid is least subject to volume change. That is, the volume change rate of the sheet of Example 1 immersed in oil is about 3%, and the volume change rate of the sheet of Example 2 is about 2% under the same conditions. The result is better than 2.

  This is thought to be due to the fact that the content of NBR latex causing oil swelling is lower in the order of Example 2, Example 1, Comparative Example 2, and Comparative Example 1 (see Table 2).

  When the core wire 30 (see FIG. 2) is processed using the RFL treatment liquid of the sheet whose volume change is large in this test, the RFL layer swells as the timing belt 10 is used, and the core wire 30 and the timing belt 10 ( The distance from the tooth bottom of FIG. For this reason, the timing belt 10 contracts so that the tooth portion 14 of the timing belt 10 wound around the pulley (not shown) is separated from the tooth bottom of the pulley, and the engagement between the timing belt 10 and the pulley is poor. Can occur.

  As is clear from the above, the volume change in the state of being immersed in oil is significantly less than the RFL layer by the RFL treatment liquid of Comparative Examples 1 and 2, and the RFL layer by the RFL treatment liquid of Examples 1 and 2 Can prevent the contraction of the timing belt 10 and the meshing failure with the pulley. In particular, it can be said that this tendency is remarkable in the RFL processing solution of Example 2. The treatment liquid for RFL treatment of the core wire 30 of the timing belt 10 used in a state where oil adheres needs to have a volume change rate of approximately 5% or less in this test.

  In addition, the RFL treatment liquid of Example 3 has a composition similar to that of Example 3 although the evaluation test using a sheet has not been performed, and Example 2 has a slightly higher NBR latex content than Example 3. Even (see Tables 1 and 2), since the results are better than those of Example 1, it is considered that the RFL treatment liquid of Example 3 is also excellent in hardness stability and shrinkage prevention properties.

  When the content of NBR latex (see Table 2) is lower than that in Example 3, and the amount of solid content (B) of NBR latex (see Table 1) relative to the solid content of RF (A) is further reduced, RF The solution and the NBR latex could not be mixed uniformly. This means that in the composition in which the solid content (B) of the NBR latex relative to the solid content (A) of RF is less than that of Example 3, the compatibility between RF and NBR latex is lowered, and it is used as an RFL treatment liquid. It means you can't. Therefore, the weight ratio of the solid content (B) of the NBR latex to the solid content (A) of RF cannot be made smaller than 1.4.

  From the above, the RFL treatment liquid adjusted in the composition range of Examples 1 to 3 is used for the RFL treatment of the core wire 30 (see FIGS. 1 and 2) of the timing belt 10 used in a state where the oil adheres. It can be said that it is suitable.

  The timing belt 10 (see FIG. 1) is used, for example, in a state where oil adheres inside a transmission device (not shown). For this reason, the tensile strength of the timing belt 10 after use for a predetermined time is evaluated as follows by a tester (not shown) simulating an actual use state. Note that the timing belt 10 subjected to the tensile strength test is embedded so that a plurality of core wires 30 (see FIG. 1) are separated at a constant interval.

  Each of the test machines is provided with a small-diameter driving pulley and a driven pulley (both not shown). The timing belt 10 travels around a drive and driven pulley. In this testing machine, it is possible to select and use drive and driven pulleys having different diameters.

  Oil (not shown) is supplied to the testing machine. The drive pulley is disposed on the lower side and the driven pulley is disposed on the upper side. Oil adheres to the timing belt 10 when traveling on the driving pulley of the testing machine. As a result, the timing belt 10 travels with oil attached to the surface. The temperature of the oil is kept at an appropriate temperature, for example, around 100 ° C. by a heater (not shown).

  Hereinafter, the result of the belt strength test of the timing belt 10 will be described. FIG. 5 is a diagram showing a relative belt strength ratio of the timing belt 10 after running for 100 hours. FIG. 6 is a diagram showing the remaining rate of the belt strength with respect to the timing belt 10 after traveling for 100 hours.

  As apparent from FIGS. 5 and 6, the belt strength test was carried out in the three strands 36 in the core wire 30 treated with any of the RFL treatment liquids of Comparative Example 1 and Examples 1 to 3 (see FIG. 2). A plurality of timing belts 10 whose upper twist number was adjusted to 2.0 times (/ inch) were performed by the above-described testing machines (see paragraphs [0040] to [0042]). FIGS. 5 and 6 are test results of the timing belt 10 in a state in which it has run for 100 hours. FIG. 5 shows the relative results of the timing belts of the respective examples when the belt strength of the comparative example 1 is 100. FIG. 6 shows the remaining ratio of the belt strength after running on the basis of the belt strength before running in each of the example and the comparative example.

  The belt strength increases in the order of Example 2, Example 1, Example 3, and Comparative Example 1 (see FIG. 5), and the residual strength ratio with respect to the belt strength before running in each of these Examples and Comparative Examples. The percentage (%) was improved to about 65 (%) in Examples 1 and 2 and about 63 (%) in Example 3 as compared to about 50 (%) in Comparative Example 1 (see FIG. 6). ). As described above, the RFL treatment liquids of Examples 1, 2, and 3 are excellent in oil resistance, that is, excellent in hardness stability and shrinkage prevention properties when the RFL layer by the treatment liquid is placed in oil. It is thought that this is due to

  As described above, according to the present embodiment, by adjusting the composition of the treatment liquid used for the RFL treatment, the timing belt 10 used in a state where oil adheres is prevented from contracting and the strength is increased over a long period. Can be maintained across.

  The RFL treatment liquid of this embodiment may be used not only for the core wire 30 of the timing belt 10 but also for a core wire such as a V belt or a V-ribbed belt. Moreover, as a latex component, although it is preferable to use NBR latex excellent in oil resistance, it is not limited to this.

It is a perspective view which fractures | ruptures and shows a part of timing belt of this embodiment. It is a perspective view which expands and shows the inside of the core wire contained in a timing belt. It is a figure which shows the result of the hardness change test of the sheet | seat formed using the RFL process liquid of a comparative example and an Example. It is a figure which shows the result of the volume change test of the sheet | seat formed using the RFL process liquid of a comparative example and an Example. It is a figure which shows the relative belt strength ratio of the timing belt after driving | running | working. It is a figure which shows the residual ratio of the belt strength with respect to the timing belt before driving | running | working after driving | running | working.

Explanation of symbols

10 Timing belt (belt)
30 strands 36 strands

Claims (5)

A belt having a cord and used in a state where oil adheres,
The core wire is treated with an RFL treatment liquid containing a rubber latex and a resorcin / formaldehyde condensate. In the RFL treatment liquid, a weight ratio of solid content of the rubber latex to the resorcin / formaldehyde condensate is 1. 4. A belt having 4 or more and 2.0 or less.   The solid content of the rubber latex is contained by 56 to 64% by weight and the solid content of the resorcin / formaldehyde condensate is contained by 32 to 40% by weight with respect to the total solid content of the RFL treatment liquid. Item 2. The belt according to Item 1.   The belt according to claim 1, wherein the rubber latex includes acrylonitrile-butadiene rubber latex. A cord used for a belt used in a state where oil adheres,
It is treated with an RFL treatment liquid containing a rubber latex and a resorcin / formaldehyde condensate, and the weight ratio of the solid content of the rubber latex to the resorcin / formaldehyde condensate is 1.4 or more and 2.0 or less. The heart line. An RFL processing liquid used for processing a core wire included in a belt used in a state where oil adheres,
An RFL treatment liquid comprising a rubber latex and a resorcin / formaldehyde condensate, wherein a weight ratio of the solid content of the rubber latex to the resorcin / formaldehyde condensate is 1.4 or more and 2.0 or less.

Images