JP2000088062A - Adhesive treatment of core wire for power transmission belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent looseness and separation of a core wire caused by steam by winding the core wire around a round rod having a prescribed diameter at a prescribed angle in a dip bath for adhesive treatment liquid, and dipping the core wire passing the adhesive treatment liquid. SOLUTION: After a core wire 8 which is not yet treated is wound around a guide roller 3 in a bath part 2, it is wound around a guide roller 4 passing over a guide roller 5, under a round rod 6, and over a guide roller 7 in order, and it is brought out from the bath part 2. The diameter of the round rod 6 is set within 5 to 50 mmϕ, and an angle for winding around the round rod 6 is set within 60 to 240 degrees. The core wire 8 which is not yet treated and which is made of a stranded code is bent with a sufficient winding angle around the round rod having a small diameter, a clearance is generated between filaments of a code, adhesive treatment liquid is permeated into the core wire 8, and thereby, each filament is almost covered by the adhesive treatment liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding process of a core wire composed of a twisted cord embedded in a power transmission belt, and more particularly, to a bonding method capable of applying an adhesive to the inside of a twisted cord.

[0002]

2. Description of the Related Art A power transmission belt is often composed of a belt main body made of an elastomer material such as rubber and a fiber for reinforcing the belt main body, and one of them is a core wire buried spirally in a longitudinal direction of the power transmission belt. As the core wire, a bundle of filaments or a twisted filament is used.

[0003] The core wire and the belt body must be firmly adhered to each other, and are adhered to each other by interposing an adhesive such as RFL (resorcinol, formalin, latex) that can adhere to both fibers and rubber. ing. In the bonding process of applying an adhesive to the core wire, an untreated core wire, which has not been subjected to the bonding process, is immersed in a bath of an adhesive treatment solution to apply the adhesive.

A method of immersing an untreated core wire in an adhesive treatment liquid in a bathtub is performed by using an apparatus as shown in FIGS. Means have been taken such as passing through, or winding the core wire between two rolls arranged in a bathtub to pass through the treatment liquid.

[0005] In addition to the purpose of bonding the core wire to the elastomer of the belt body, the bonding of the core wire has a purpose of preventing fraying of the core wire made of a twisted cord or the like, and the adhesive is sufficiently adhered. This can prevent the core wire from fraying. This effect is also important especially for a type of core wire such as aramid fiber where fraying is likely to occur.

[0006]

However, an adhesive such as RFL can form a uniform coating on the cord surface but penetrate into the interior of the cord even when the cord is normally passed through the bonding solution. The processing solution does not reach the inside of the bundled filaments even if it is not bundled, and a sufficient amount of adhesive does not adhere to the inner filaments. There is a problem.

As a measure against fraying, for example, Japanese Patent Laid-Open No. 61-1
No. 66838 discloses a method of collecting and twisting aramid fibers which have been subjected to a bonding treatment in advance, and performing another bonding treatment. By using this method, the purpose of preventing fraying can be achieved, but the bonding process must be performed twice, which leads to an increase in cost. Furthermore, in this method, the strength of the rope is greatly reduced by twisting.

When the fiber to be bonded is PET (polyethylene terephthalate) or aramid fiber, the fiber is first treated with a treatment liquid containing an isocyanate compound or an epoxy compound in order to activate the fiber and make it adhere.
The second treatment is performed with the RFL solution. In that case, a solvent-based treatment liquid was used for the first treatment.

In recent years, due to environmental problems, the use of aqueous treatment liquids instead of solvent-based adhesion treatment liquids has been increasing. Unlike the solvent-based treatment liquid, the aqueous treatment liquid does not generate solvent vapor and has no danger of explosion, so there is an advantage that there is no need to take explosion-proof measures.

On the other hand, when the first treatment is performed with an aqueous treatment liquid, the adhesion is inferior in steam resistance, and peels off at the interface between the fiber and the adhesive due to steam that is applied when vulcanizing the belt. There is a problem. The reason for this is that when treated with an aqueous treatment solution, it is difficult for the adhesive to form a uniform film, and the fiber is inevitably left in places where the fibers are exposed, and vapor reaches and separates there. Conceivable.

In order to eliminate the cause, when the RFL is applied in the second process after the first process, the RFL solution is penetrated into the core wire, and the filament hidden inside is also removed by the RF process.
A method of completely covering with L is conceivable.

In order to solve the above-described problem, the inside of a core wire in which a plurality of filaments are bundled and twisted is inserted into the core.
Provided is a method for bonding a core for a power transmission belt, in which the FL liquid is allowed to reach to prevent the core from fraying or peeling by steam.

[0013]

According to the present invention, there is provided a method for bonding a transmission belt core wire comprising a twisted cord buried in a belt to reinforce the transmission belt. 60-240 ° on 50mmφ round bar
And immersion by passing through the adhesive treatment liquid at an angle of.

[0014] By winding the core wire around a relatively small-diameter round bar as described above, a gap is generated between the bundled filaments. In addition, the treatment liquid penetrates into the inside of the core wire, so that the adhesive can be sufficiently covered.

According to a second aspect of the present invention, in the method of bonding a core for a power transmission belt, the first processing is performed with a water-based adhesive, and then the second processing is performed by RFL.
In the bath of liquid, wire the core wire to a round bar
It is characterized in that it is wound at an angle of up to 240 ° and the RFL solution is passed through and immersed.

When the first processing liquid is a water-based adhesive, a sufficient coating is not formed on the core wire, but since the above-described method is employed in the second processing, the RFL solution is sufficiently provided inside the core wire. To protect the fibers against vapors that may be applied in the subsequent vulcanization step.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A method for bonding a core wire for a power transmission belt according to the present invention will be described with reference to an example in which a cord made of aramid fiber is used. A filament made of aramid fiber is bundled, twisted and then twisted to form an untreated core.

Then, the substrate is immersed and dried in the first processing liquid which is an aqueous processing liquid, and subsequently immersed in the RFL liquid which is the second processing liquid. Apparatus 1
Is as shown in FIG. 1, a bathtub 2 for storing the processing liquid S, a rotatable guide roller 3 mounted on one end of the bathtub 2 and a rotatable guide roller 3 mounted on the other end. A guide roller 5, a small-diameter round bar 6, and a guide roller 7 are arranged at different levels between the discharge-side guide roller 4 and the two guide rollers 3, 4.

Among them, two guide rollers 5 at both ends,
The central round bar 6 is positioned lower in the bathtub 2 than in the center 7, and is arranged so that the entire round bar 6 is immersed in the adhesive treatment liquid S stored in the bathtub 2. At least the central round bar 6 is fixed so as not to rotate.

By passing the unprocessed core wire 8 which has not been subjected to the bonding process through the processing apparatus 1 as described above,
The untreated core 8 is immersed in the adhesive treatment liquid S to obtain the treated core 8, and the untreated core 8 is first wound around the guide roller 3 in the bathtub 2. , Pass over the guide roller 5, and then under the round bar 6, guide roller 7
Finally, it is wound around the guide roller 4 and pulled out of the bathtub 2.

As described above, by feeding the unprocessed core wire 8 over the small-diameter yet non-rotating round bar 6, the unprocessed core wire 8 is squeezed by the round bar and a gap is generated between the filaments. The processing liquid permeates the gap.

The round bar 6 is a characteristic part of the present invention. As shown in FIG. 2, the diameter d of the round bar 6 is in the range of 5 to 50 mmφ, more preferably in the range of 10 to 40 mmφ. Used. In addition, the winding angle θ around the round bar 6 can be set to 60 to 60 by adjusting the positions of the rollers 5 and 7 on both sides.
The range is 240 °, more preferably 100 to 200 °.

The untreated core wire 8 made of a twisted cord is bent by winding it around a small-diameter round bar at a sufficient winding angle θ, so that a gap is formed between the filaments of the twisted cord, and the bonding solution is applied to the core. The filament penetrates into the inside of the wire 8 and each filament is almost covered with the bonding solution.

If the diameter d of the round bar 6 is less than 5 mmφ, the core wire 8 is excessively bent, and the strength of the core wire 8 is reduced.
If it exceeds 50 mmφ, a gap between the filaments cannot be secured, and the treatment liquid cannot sufficiently penetrate into the inside.

The winding angle θ of the core wire 8 around the round bar 6
If the angle is less than 60 °, the time required to pass through the processing liquid with a gap between the filaments becomes short, and the processing liquid cannot be sufficiently penetrated. 240
When the angle exceeds 0 ° C, the resistance between the core wire 8 and the round bar 6 increases in the section between the rollers 5 and 7 and the round bar 6, so that a load is applied to the core wire 8 and the strength of the core wire 8 decreases. Would.

As described above, by using the treatment method of the present invention in the second treatment, it is possible to make the second treatment liquid penetrate into the core wire 8 even when an aqueous treatment liquid is used in the first treatment. Therefore, even if the belt is formed using the core wire 8 and the belt is vulcanized by steam, the steam is covered with the adhesive formed by the second process, and the steam directly touches the filament. Therefore, the steam resistance of the core wire 8 can be improved.

Further, even in the case of using a fiber such as aramid, which is liable to cause fraying due to sufficient penetration of the adhesive into the cord, an effect of preventing fraying can be expected.

Examples of the material of the cord 8 used in the present invention include cords made of cords of high strength and low elongation, such as aramid fibers, polyester fibers such as polyethylene terephthalate, and polyparaphenylene benzobisoxazole fibers. When aramid fibers are used, fraying is more likely to occur than when other fibers are used, so that the effect of preventing fraying of the present invention is remarkable.

The first processing liquid may be 4, 4
'-Diphenylmethane diisocyanate, tolylene 2,
Isocyanate compounds such as 4-diisocyanate, P-phenyldiisocyanate, and polyarylpolyisocyanate.

Also, ethylene glycol, glycerin,
Reactive products of polyhydric alcohols such as pentaerythritol, polyalkylene glycols such as polyethylene glycol and halogen-containing epoxy compounds such as epichlorohydrin, resorcinol, bis (4-hydroxyphenyl) dimethylmethane, phenol-formaldehyde resin, resorcinol -Reaction products with polyhydric phenols such as formaldehyde resins and halogen-containing epoxy compounds.

These reaction products are used by being mixed with water, an organic solvent such as toluene or methyl ethyl ketone.
Recently, the environmental issues of organic solvents have been taken up,
Adhesives mixed with water have come to be used frequently, in which case the core wire can be sufficiently covered with the RFL solution by performing the method of the present invention in immersion in the second processing solution. it can.

The first treatment liquid may not be used depending on the type of fiber, and may be treated only with the second treatment liquid described below.

The RFL liquid as the second processing liquid is a mixture of an initial condensate of resorcinol and formalin and rubber latex.

The type of the belt to which the cords processed by the method of the present invention are applied is not particularly limited, and any type of belt such as a wrapped belt, a low-edge belt, a V-belt, a V-ribbed belt, and a toothed belt can be used. The present invention is also applicable to belts.

[0035]

EXAMPLES Next, the effects of the present invention were confirmed by carrying out Examples and Comparative Examples of the present invention.

Two untreated core wires A and B of PET (polyethylene terephthalate fiber) and aramid as shown in Table 1 were treated as the first treatment liquid with an aqueous blocked isocyanate compound as shown in Table 2. Liquid and a first treatment under the condition of 200 ° C. × 20 minutes, and then using an RFL solution as shown in Table 3 as a second treatment liquid at 100 ° C.
This was carried out under the conditions of × 1 minute (drying) and 230 ° C. × 2 minutes (baking) using a processing apparatus as shown in FIG.

The peeling force between the core wire and the rubber bonded to the chloroprene rubber compound shown in Table 4 and arranged without gaps in a width of 25 mm was measured at room temperature. The rubber coverage of the release surface on the core wire side was expressed as a percentage.

(Embodiment 1) In Embodiment 1, a cord made of PET of A shown in Table 1 was used as a core material, and
The treatment liquid is shown in Table 2. In the second treatment, the round bar 6 shown in FIG. 1 was used with a diameter of 5 mm and the winding angle was set to 180 °. JISL-1017
(1983), the strength of the core wire, the flat peeling force before and after steam exposure, and the rubber adhesion rate on the peeled surface before and after steam exposure were measured. Table 5 shows the results.

Example 2 Example 2 was carried out under the same processing conditions as those of Example 1, except that the diameter of the round bar 6 in FIG. 1 was changed to 20 mm.

Example 3 Example 3 was carried out under the same processing conditions as in Example 1, except that the diameter of the round bar 6 in FIG. 1 was changed to 50 mm.

Example 4 Example 4 was performed under the same processing conditions as in Example 2 except that the winding angle around the round bar 6 in FIG. 1 was 60 °.

Example 5 Example 5 was carried out under the same processing conditions as in Example 2 except that the winding angle around the round bar 6 in FIG. 1 was 240 °.

Example 6 In Example 6, the first treatment liquid was prepared as shown in Table 2.
The same materials and cords as in Example 2 were used under the same processing conditions except that the above-mentioned was used.

Example 7 Example 7 was carried out under the same processing conditions as in Example 2 except that a core wire made of the material B made of aramid shown in Table 1 was used.

Comparative Example 1 Comparative Example 1 was the same as Example 2 except that the round bar 6 shown in FIG. 1 was omitted in the second treatment and an apparatus having only rolls 3 and 4 at both ends was used. This was performed under the same processing conditions as the core wire.

(Comparative Example 2) In Comparative Example 2, the first treatment liquid was prepared as shown in Table 2.
The process was performed under the same processing conditions as in Example 2 except that the round bar 6 shown in FIG. 1 was omitted in the second process and an apparatus having only rolls 3 and 4 at both ends was used.

The results of Examples 1 to 7 and Comparative Examples 1 and 2 are shown in Table 5.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

[0051]

[Table 4]

[0052]

[Table 5]

Next, the relationship between the tensile strength of the core wire and the flat peeling force after steam exposure with respect to the diameter of the round bar shown in Table 5, and the tensile strength and steam of the core wire with respect to the winding angle of the core wire around the round bar. The relationship with the flat peel force after exposure is shown in the graphs of FIGS.

Normally, when used as a core of a power transmission belt, the tensile strength of the core after treatment is at least about 600 N, and the flat peeling force after exposure to steam is 200 N / 25 mm.
Some degree of power is required. Considering this, the graphs of FIGS. 3 and 4 show that the diameter of the round bar is suitably in the range of 5 to 50 mm.

Further, from the graphs of FIGS. 5 and 6, it is understood that those in which the winding angle of the core wire around the round bar deviates from 60 to 240 ° have insufficient strength to be used as the core wire.

Further, when comparing Examples 1 to 7 shown in Table 5 with Comparative Examples 1 and 2, the numerical values of the Examples were superior in both of the flat peeling force and the rubber adhesion rate on the peeled surface after the steam exposure. Yes,
It is recognized that the steam resistance is improved by implementing the present invention.

[0057]

According to the present invention, there is provided a method of bonding a core for a power transmission belt comprising a twisted cord embedded in the power transmission belt to reinforce the power transmission belt. It is characterized in that the immersion treatment is performed while being wound around the rod at an angle of 60 to 240 ° and passed therethrough.

By winding the core wire around a relatively small-diameter round bar as described above, a gap is formed between the bundled filaments. In addition, the treatment liquid penetrates into the inside of the core wire to sufficiently coat the adhesive, and the problem of fraying of the core wire and the like can be solved.

According to a second aspect of the present invention, in the method of bonding a core for a power transmission belt, the first processing is performed with an aqueous adhesive, and then the second processing is performed by RFL. It is characterized in that the core wire is wound around a round bar having a diameter of 5 to 50 mmφ at an angle of 60 to 240 ° and the RFL solution is passed through and immersed.

When the first treatment liquid is a water-based adhesive, a sufficient coating is not formed on the core wire, but since the above-described method is employed in the second treatment, the RFL solution is sufficiently provided inside the core wire. To protect the fibers against vapors that may be applied in the subsequent vulcanization step.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a state in which a method of bonding a power transmission belt core wire according to the present invention is performed.

FIG. 2 is an enlarged view in which a cord is wound around a round bar.

FIG. 3 is a graph showing the relationship between the diameter of a round bar and the tensile strength of a treated cord.

FIG. 4 is a graph showing the relationship between the diameter of a round bar and the flat peel force after steam exposure.

FIG. 5 is a graph showing a relationship between a winding angle of a cord around a round bar and a tensile strength of a treated cord.

FIG. 6 is a graph showing a relationship between a winding angle of a cord around a round bar and a flat peeling force after steam exposure.

FIG. 7 is a schematic diagram of a conventional processing apparatus.

FIG. 8 is a schematic diagram illustrating another example of a conventional processing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing apparatus 2 Bath part 3 Guide roller 4 Guide roller 5 Guide roller 6 Round bar 7 Guide roller 8 Core wire

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 4F071 AA10A AA13B AA41A AA46B AA55A AA56B AC12A AH19 CA04 CB02 CB03 CC06 CD03 CD08 4F072 AA04 AB02 AB05 AB06 AB24 AC06 AC10 AD02 AG06 AG14 AH04 AH21 AH32 AL19

Claims (2)

[Claims] In a method for bonding a core for a power transmission belt comprising a twisted cord, the core is wound around a round bar having a diameter of 5 to 50 mm at an angle of 60 to 240 ° in a bath of the bonding liquid. A method for bonding a core wire for a power transmission belt, wherein the core wire is passed through and immersed. 2. A method for bonding a core for a power transmission belt in which a first treatment is carried out with a water-based adhesive and then a second treatment is carried out by RFL. To a round bar with a diameter of 5 to 50 mmφ
A method for bonding a core wire for a power transmission belt, wherein the core wire is wound at an angle and passed through the RFL solution.