JPS6046010B2 - Processing method of fiber material for rubber reinforcement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating a fiber material for comb reinforcement, and more particularly to a method for treating a fiber material for comb reinforcement to improve the adhesion between the fiber material for comb reinforcement and rubber.

Synthetic resins, especially polyamide fibers and polyester fibers, have high strength and high fatigue resistance, so they have been widely used as reinforcing fiber materials for comb products such as tires, transmission belts, conveyance belts, and hoses. There is.

These comb reinforcing fiber materials are usually made with resorcinol in the form of cords or blind fabrics to strengthen the bond with the rubber.
It is treated with formalin and latex liquid (hereinafter referred to as RFL treatment). The RFL treatment consists of a so-called dipping step in which a rubber reinforcing fiber material (hereinafter simply referred to as cord) is soaked in a 10-30% aqueous dispersion of resorcinol, formalin, and a rubber latex compound, followed by a drying step and a hot stretch baking step. . It is known that air bubbles (hereinafter referred to as blisters) often occur on the surface of the dipping cord during the drying, hot stretching, and baking steps in this RFL treatment. These blisters not only cause contamination of the RFL processing equipment, but also reduce the adhesive strength between the rubber and the cord, increase the variation in adhesive strength, decrease the adhesive strength retention rate, and cause air gaps between the comb and the cord in the tire to cause damage to the tire while it is running. Failure due to separation may result. Conventionally, it has been a general idea that blisters are generated due to the influence of the initial drying temperature, and the higher the initial drying temperature, the more likely the amount of blisters generated increases.

This is because if the cord is dried at a high temperature (120 to 150°C) that causes baking of the RFL in the early stage of drying, a thin RFL film will be formed on the outermost layer of the cord due to baking, and this will cause the moisture inside the cord to evaporate. In order to prevent
It is thought that the water vapor pressure inside the cord increases significantly, and as a result blisters suddenly occur in weak membranes. Therefore, if a gradual temperature increase method is adopted instead of a low initial drying temperature or rapid heating, the gas inside the cord can be expelled before the RFL film is formed on the outermost layer, and the occurrence of prister can be suppressed. Although this method is possible to some extent, it is not a preferable method because it would increase the length of the drying equipment, prolong the drying time, and reduce productivity. The present invention eliminates the various drawbacks caused by pristar by suppressing the occurrence of pristar regardless of the drying conditions and baking conditions without causing such a decrease in productivity or process disadvantages. Yes, and the gist is that at any stage before the rubber reinforcing fiber material is treated with resorcinol, formalin, and latex, (a) polypropylene glycol with a molecular weight of 600 or more, and (b) propylene oxide/ethylene oxide random with a molecular weight of 1000 or more. A copolymer (with a molar ratio of propylene oxide and ethylene oxide of 1:3 to 3:1) and (c) a higher fatty acid ester of a trivalent or higher polyhydric alcohol to which propylene oxide or propylene oxide and ethylene oxide are added. One or more compounds selected from compounds (however, the amount added is 10 moles or more in the case of propylene oxide alone, and at least 5 moles or more of the former in the case of co-addition of propylene oxide and ethylene oxide). This is a method for treating fiber materials for comb reinforcement, characterized in that the treatment is carried out using a treatment liquid containing the present invention.

Polypropylene glycol (hereinafter referred to as PPG) in the present invention
) must have a molecular weight of 600 or more; if it is less than 600, the effect of suppressing the occurrence of pristar is not significant. PPG has a molecular weight of 600 to 2000, especially 1
000 to 1500 is preferred. In addition, propylene oxide/ethylene oxide random copolymer (hereinafter referred to as PO/EO random copolymer, rimer) has a molecular weight of 1.
000 or more and a copolymerization ratio of 1:3 to 3:1 is advantageous; those with a molecular weight of less than 100 and those with a copolymerization ratio outside the above range do not have a sufficient effect of suppressing the generation of prister. The PO/EO random copolymer preferably has a molecular weight of 1000 to 5000, particularly 1500 to 3000. In addition, for compounds in which propylene oxide or propylene oxide and ethylene oxide are added to higher fatty acid esters of trihydric or higher polyhydric alcohols, the amount added is 10 moles or more when propylene oxide alone is added, and the amount added is 10 moles or more when propylene oxide is alone, and when the amount is 10 moles or more when propylene oxide is added alone. In this case, it is necessary that the amount of propylene oxide is 5 moles or more, and if the amount added is less than this, the effect of suppressing the generation of blister is poor.

Trimethylol ethane, trimethylolpropane, pentaerythritol, trivalent or higher polyhydric alcohols,
Zorbitan, glycerin, etc. are preferred), and saturated or unsaturated fatty acids having 12 to 18 carbon atoms are suitable as the higher fatty acids.

The higher fatty acid ester of polyhydric alcohol must be capable of adding propylene oxide or both propylene oxide and ethylene oxide, and therefore, in the case of a partial ester or a complete ester, the molecular It has a hydroxyl group or active hydrogen within it. In the present invention, a compound appropriately selected from the compounds shown in (a), (c), and (c) above is applied to the rubber reinforcing fiber material/material at any stage before RFL treatment. However, it is preferable to include these compounds in the spinning oil solution and carry out the treatment simultaneously with the spinning oil treatment, since the process is not complicated.

Instead of containing it in the spinning oil solution, it is of course possible to provide it in a liquid form by providing an independent treatment step at any step after yarn protection and before RFL treatment. The desired effect can be sufficiently achieved if the compound is uniformly deposited on the fiber material to be treated in an amount of about 0.03% by weight or more. Next, the effects of the present invention will be explained using examples.

Example 1 In the melt spinning of nylon 6 fibers for tire cords, various spinning oils as shown in Table 1 were added as a 10% aqueous emulsion using an oiling roller according to a conventional method, and the undrawn yarn thus obtained was Stretched and heat treated according to a conventional method to obtain a 1620Ci/204f yarn, and two of these yarns were twisted to form a 40×40T/10cm
A cord is made, and then a blind fabric (cord density: 10 cords/in) is manufactured from this cord, which is then subjected to RFL treatment (solid matter adhesion amount: 8%) according to a conventional method, and then heated at 120° C. for 1 minute. After drying, hot stretching and baking were performed at 200°C. The number of pristars generated in the thus obtained blind fabric, the adhesion strength (H test) of the test piece obtained by combining it with rubber and vulcanization molding according to a conventional method, the variation in adhesive strength (standard deviation), and the adhesive strength retention rate. (JISL-
Table 1 shows the ratio of the adhesion force after 3 Gin fatigue to the adhesion force before fatigue according to the 1017 tube fatigue test.

As shown in Table 1, the products that belong to the present invention (those using oils A to C) have a significantly higher number of beblister formations than the conventional products that do not belong to the present invention (those that use oils D and E). It can be seen that the adhesive force and adhesive force retention are excellent, and the variation (standard deviation) of the adhesive force is small.

Example 2 A test was conducted under the same conditions as in Example 1 except that the spinning oil shown in Table 2 was used in place of the spinning oil in Example 1.

Claims (1)

[Claims] 1 At any stage before rubber reinforcing fiber materials are treated with resorcinol, formalin, or latex, (a) polypropylene glycol with a molecular weight of 600 or more, (b) propylene oxide/ethylene oxide random copolymer with a molecular weight of 1,000 or more (but , the molar ratio of propylene oxide and ethylene oxide is 1:3 to 3:1) and (c) a compound in which propylene oxide or propylene oxide and ethylene oxide are added to a higher fatty acid ester of a trivalent or higher polyhydric alcohol (however, The amount added is 10 moles or more in the case of propylene oxide alone,
In the case of co-addition of propylene oxide and ethylene oxide, at least 5 moles or more of the former is used. How materials are processed.