JPS585243A - Method of bonding aromatic polyamide fiber and rubber compound - Google Patents

Abstract

PURPOSE:To improve the flex resistance and the adhesion, by immersing an aromatic polyamide fiber in a solution containing a mixture of an epoxy compound with a liquid rubber in a specified proportion, and treating it with a liquid mixture containing resorcinol and formalin in a specified proportion. CONSTITUTION:An aromatic polyamide fiber such as a poly-p- or m-benzamide fiber or a poly-p-phenyleneterephthalamide fiber is treated with a solution of a mixture containing an epoxy compound having at least one epoxy group and a liquid rubber in a weight ratio of 1 to 0.01-1 to 1, and is dried at 180-200 deg.C. Then it is treated with a resorcinol/formalin/rubber latex mixture containing resorcinol and formalin in a molar ratio of 1 to 0.5-3 and is firmly contacted with an unvulcanized rubber followed by vulcanization, so that the aromatic polyamide fiber and the rubber compound are bonded.

Description

[Detailed Description of the Invention] Flexural stability in a composite with. The present invention relates to a fiber processing method with excellent adhesive properties.

Generally, rubber hose. Transmission belt, conveyor belt,
Industrial rubber products such as taiki are reinforced using fiber materials for rubber reinforcement, but recently polyamide fibers have been used as such fiber materials to improve the performance of industrial rubber products. Aromatic polyamide fibers, such as the trade name Kepler, which have better physical properties than polyester fibers, have come to be widely used.

However, aromatic polyamide fibers are high-strength, high-modulus organic fibers with good thermal stability and strength and modulus retention under high temperature and high humidity conditions, and excellent dimensional stability in heat and hot water. However, there are drawbacks such as poor adhesion with rubber compounds and poor bending stability when made into a composite, and various methods for improving these problems have been studied.

In other words, the conventional method for making such improvements is to use υ resorcinol-formalin-rubber latex adhesive (
(hereinafter referred to as IFL liquid) Method 2) There is a method of using RFL liquid after pretreatment with an epoxy or incyanate compound, but the former method has good bending stability but poor adhesion. On the other hand, the latter method has good adhesion but has drawbacks such as hardening of the fibers and poor bending stability, and neither of these methods has necessarily been completely satisfied.

The object of the present invention is to improve the drawbacks of aromatic polyamide fibers in composites with such rubber compounds.

That is, the present invention provides an aromatic polyamide fiber, an epoxy compound having at least one epoxy group, and a liquid rubber. ! It is characterized in that it is treated with a solution mixed at a weight ratio of 1:0.01 to 1:1, dried, immersed in RFL liquid, and then heat-treated to be bonded to the rubber compound. .

The aromatic polyamide fiber used in the present invention means that the fibrous material is polyp- or m-benzamide or poly-
It refers to p-7 enylene terephthalamide fibers, m-phenylene isophthalamide fibers, and rubber compounds used as adherends include SBR, EPT,
These include IR, OR, NR, etc. alone or a blend thereof, and among these, an OR mixture alone or a blend thereof is most preferred.

The epoxy compound used in the treatment solution of the present invention is a compound having at least one epoxy group in its molecule, such as a reaction product of glycerin, propylene glycols, and halogen-containing epoxy compounds such as evichlorohydrin. or an epoxy compound obtained by fermenting an unsaturated bond with peracetic acid or the like, and a reaction product of a polyhydric phenol such as hydroquinone or bisphenol A with a halogen-containing epoxy, etc., and these may be used as appropriate.

On the other hand, the liquid rubber used in the present invention refers to liquid polyphtadiene having a terminal carboxyl group, hydroxyl group, amino group, etc., liquid nitrile rubber having a terminal carboxyl group, and the like. Among these, liquid chloroprene rubber is most preferred in terms of adhesiveness and bending resistance.

Therefore, the treatment liquid consisting of an epoxy compound and a liquid rubber is composed of an epoxy compound and a liquid rubber in a ratio of l:o, 01 to 1:1.
It is mixed into a solvent, etc., and used in the form of a solution or suspension (%) such as an emulsion, so that the polymerization ratio is .In this case,
The amount of liquid rubber used is 0.
If it is less than 01, the hood becomes very hard and has poor bending resistance.

Also, conversely, the amount of liquid rubber is 1 to 1 of epoxy compound.
In the above case, the hood becomes soft because the soft segment of the liquid rubber enters the filament of the cord, but the adhesive force decreases because the number of functional groups is small. Therefore, the blend ratio of the epoxy and liquid rubber is important.

After immersing the aromatic polyamide fiber in the pretreatment liquid prepared as above and drying it at 180 to 200°C,
The fibers are heat treated at 180-200°C and then RF
The RFL liquid used here is a mixture of an initial condensate of resorcin and formalin with rubber latex, and in this case, the molar ratio of resorcin and formalin is 1:0.5 to 3. This is suitable for improving adhesive strength.

This is because if the amount of formalin is 0.5 mol or less or 3 mol or more per 1 mol of resorcin, an initial condensate having a molecular weight necessary for adhesion will not be formed.

The rubber latex mentioned above is usually a synthetic rubber latex, and this synthetic rubber latex refers to chloropre/rubber latex or styrene-phthadiene-vinylpyridine rubber latex, which can be used alone or in combination.

The adhesive-treated fibers do not lose any adhesive strength even after being stored for a long period of time compared to conventional methods, and are used in applications such as power transmission belts, conveyor belts, tires, etc. that require adhesive strength and bending resistance. It is extremely suitable for application to products for general use.

The present invention will be explained more specifically and in detail below using Examples.

Example 1 After immersing an aromatic polyamide fiber cord having a composition of 1500D/□X4 (using DuPont's product name Kepler) in pretreatment solutions (A) and (B) having the composition shown in Table 1, respectively, The sample was dried at 19Q'c for 2 minutes, immersed in an RFL solution having the composition shown in Table 2, and reacted at 200°C for 2 minutes. Next, the hood treated in this way was spun onto an adhesive tape spread on a drum, and a 0.5 tan thick
The chloroprene rubber formulations in Table 3 were laminated. Thus, the sample R cut sheet stacked in this way was heated at 150℃ for 30 minutes.
Vulcanize for minutes, and after curing, cut the sample into 2.5 cm wide pieces and use a peeler tester (using Shimabara Seisakusho's Autograph).
Tensile speed 5o 111111. Adhesive strength was measured at −.

The results are shown in Table 4. In addition, the conventional method (0) is a case in which the sample is not immersed in the pretreatment liquid but only in the RFL liquid shown in Table 2.

Table 1 (Weight f) Sen1 Denki Kagakusha Terminal epoxy, carboxyl group (7)
Liquid & Chloroprene Rubber Table 2 RFL liquid formulation Table 3 Rubber formulation (weight?) Table 4 Comparison of adhesive strength between the method of the present invention and the conventional method Example 2 Each cord treated in Example 1 was placed on a separate drum. Thickness of 1. A chloropyrene rubber compound of Table 3 of OTM was spun, and a chloropyrene rubber compound of the same thickness and composition was laminated on top of the chloropyrene rubber compound of Table 3 of OTM. This embedded sample was created. This sample was wound around a rotating bending bar located in the vertical direction, one end of the sample was fixed to a frame, a load was applied to the other end, and the rotating bending bar was attached to a bending test machine that reciprocated up and down. ．． After bending was repeated 5000 times, the strength was measured at a tensile speed of 50 mm.

The results were as shown in Table 5.

Table 5 Example 3 Cords treated with the pretreatment solution (A) of Example 1 by appropriately changing the weight ratio of epoxy/liquid chloroprene rubber were treated as in Example 1. Adhesion test was carried out in the same manner as in Example 2.
I did a bending test.

The results are shown in Table 6.

Table 6: Variable comparison of epoxy/liquid chloroprene rubber plow weight ratio Example 1. An adhesion test and a bending test were conducted in the same manner as in Example 2. The results are shown in Table 8.

Table 8 Comparison of types of liquid rubber Table 1 Types of liquid rubber (weight) Mine 2; Denki Kagakusha Liquid chloroprene rubber with terminal carboxyl group Example 5 Treated with the pretreatment liquid (A) of Example 1 code 2
They were dried at 190°C for 2 minutes, and then immersed in RFL liquids having the compositions shown in Table 2 of Example 1, in which the molar ratio of resorcinol to formalin was changed to k/, 200°C.
The reaction was carried out at ℃ for 2 minutes. The code processed in this way is then used in Example 1. An adhesion test and a bending test were conducted in the same manner as in Example 2. The results were as shown in Table 9.

Claims (1)

[Claims] l When adhering aromatic polyamide fibers and rubber compounds, does the fiber contain at least one epoxy group? The epoxy compound and the liquid rubber 'il:0.01 to l:1
After being immersed in a solution mixed in a weight ratio of
A method for adhering aromatic polyamide fibers and a rubber compound, which comprises treating with an RFL liquid mixed in molar proportions, and then vulcanizing the same in close contact with unvulcanized rubber.