Field of the Invention

The present invention relates to technical textile materials with high raw adhesion value and an optimized production method which is developed to obtain these textile materials.

Background of the Invention

The present invention relates to technical textile materials with a high raw adhesion value and production method of these textile materials. The textile materials of the present invention can be used as reinforcement materials in rubber-containing products, such as tires, belts, and pipes. The textile material with high raw adhesion can be used in certain layers of the tire, such as the belt, carcass, sidewall, and bead area. For example, the said textile material may be cord fabric, which is obtained by weaving twisted raw yams and used as reinforcement material by bonding with special adhesive mixtures in various parts of the tire, and which is a complex and composite product consisting of one or several layers.

Resorcinol formaldehyde latex (RFL) is commonly used to ensure adhesion between textile materials and rubber-containing products. The textile material is coated with RFL by being dipped in an RFL dipping, thereby increasing the adhesion of the textile materials to each other and to the rubber product. The commonly used RFL dipping is obtained by dissolving resorcinol in water and adding formaldehyde and alkaline component (e.g., sodium hydroxide or ammonia), thereby obtaining an aqueous solution of the resin, which is slowly added to the latex with thorough stirring and preferably left to rest and mature for 24 hours. Two-layer coatings are made to increase raw adhesion and RFL solution is used in both layers. In addition, different chemicals can be added to the RFL solution in the second layer.

For example, US 8,651,157 discloses compositions and methods for improving the adhesion of textile materials. The said textile material is coated with RFL as the first layer, and coated with resorcinol-formaldehyde, rosin ester, and unvulcanized rubber as the second layer. In the second layer, toluene/hydrocarbon solvents, xylene, ethyl acetate, alcohols, ethers, and mixtures thereof are used as solvents.

Table 1 Physical properties of cord fabrics coated with RFL as the first layer, and RFL and rosin adhesive as the second layer

However, the targeted raw adhesion values cannot be achieved with coatings made by using RFL and different chemicals. Table 1 shows the average strip adhesion and raw adhesion values of cord fabrics known in the state of the art , coated with RFL as the first layer, and a mixture of RFL, and Struktol LT 395C, which is a rosin ester resin, as the second layer, and produced using a double-mouthed dewebber system. Fusing refers to the mechanical adhesion between the textile material and the tire and raw adhesion refers to the mechanical adhesion between the textile materials. In this table, the targeted fusing and raw adhesion values are taken as 100 and the adhesion values obtained are given as percentages. As can be seen from the table, while the fusing was higher than the desired value, the raw adhesion performance was well below the target performance. Although process changes were made between trials, the raw adhesion values were low. Therefore, there is a need to develop textile materials with increased raw adhesion values compared to the state of the art. As described above, raw adhesion refers to the adhesion value of textile materials to each other. Textiles used as reinforcement materials in rubber-containing products may comprise more than one layer of textile material. Therefore, the adhesion of these textile materials to each other is as important as the adhesion to the rubber material. For example, the high level of raw adhesion prevents damage such as possible tears, especially in the bead area of the tire.

Summary of the Invention

The objective of the invention is to obtain textile materials with high raw adhesion value by using coating solutions with an increased natural latex ratio.

Another objective of the invention is to obtain a textile material with a raw adhesion value which has a similar performance with natural latex, without the need for an additional tacky finish chemical, unlike the state of the art.

Brief Description of the Figures

Textile materials with high raw adhesion value and the production method which is developed to achieve the objective of the present invention is illustrated in the accompanying figures, in which:

Figure 1 - is an illustration of a Leno weave used for weaving a textile material within the scope of the invention.

Figure 2 - is a different illustration of a Leno weave used for weaving the textile material within the scope of the invention.

Detailed Description of the Invention

The present invention provides compositions to enable that textile materials and the rubber-containing materials are adhered to each other. The textile materials coated with these compositions can be used in certain layers of the tire, such as the belt, carcass, sidewall, and bead area. Within the scope of the invention, in addition to a dipping composition with an increased natural rubber ratio, a novel production process is developed. By finishing the textile material with this dipping solution, the raw adhesion value is increased.

The textile materials of the present invention may be woven, non-woven or knitted fabrics. The said textile materials may comprise synthetic yams, natural yams or mixtures thereof. In a preferred embodiment of the invention, the said textile material is a cord fabric. In a more preferred embodiment of the invention, the said cord fabric is composed of a textured fiber. In a more preferred embodiment of the invention, the said cord fabric is a leno weave fabric. The use of textured fiber increases the raw adhesion value and leno weave prevents the cords from extending out of the strip edges in strip cutting.

The textile material of the present invention, which is finished to have a high raw adhesion value, comprises the following:

- a textile material,

- a first coating material containing resorcinol formaldehyde latex (RFL) on at least one surface of the textile material, and

- an adhesive composition containing a diluted mixture of natural latex as the second finishing coating applied on the first coating material .

The textile material of the present invention is obtained with the following steps:

- obtaining textile material,

- taking the textile material to the finishing unit,

- dipping the textile material in resorcinol formaldehyde latex (RFL) dipping solution to form the first coating layer,

- drying the textile material, which is dipped in RFL dipping solution, at a temperature of 130-200°C, - dipping the textile material in a second adhesive composition containing a diluted mixture of natural latex to form a second coating layer for the dried textile material, and

- drying the second coating layer at a temperature of l00-150°C.

A textile material with high raw adhesion, which is obtained with the above- mentioned method steps, can be used in the belt, carcass, sidewall, and bead area layers of the tire. In one embodiment of the invention, the textile material can be used as fabric or by being cut into strips. The textile materials to be used by being cut are cut into strips.

The textile material used in a preferred embodiment of the invention is obtained by using a texturized yam and a weaving system called Leno weaving. As can be seen in Figures 1 and 2, Leno weaving prevents the textile material from protruding at the edges of the strip during strip cutting. In leno weaving (cross weave), the warp yams (C) are not placed parallel to each other and are allowed to turn around the weft yam (A).

In one embodiment of the invention, the ratio of natural latex in the natural latex mixture may be in the range of 20-100% by weight. In a more preferred embodiment of the invention, the ratio of natural latex in the natural latex mixture may be in the range of 20-60% by weight.

As can be seen in Table 2, different trials at laboratory scale were carried out to compare the raw adhesion and fusing values of the textile materials obtained by using the second coating material containing diluted natural mbber of the present invention with the state of the art. RFL was used as the first coating material in all trials. As the examples of the state of the art, RFL and Struktol LT 395C, which is rosin ester resin, were used as the second layer in trial 5; RFL and GOVITACK PBM, which is paraffin wax emulsion, were used as the second layer in trial 6; and RFL and Orgal EXP 102, which is aqueous acrylic polymer solution, were used as the second layer in trial 7. As an example of the second layer coating composition consisting of diluted natural latex of the present invention, aqueous solution containing 20% natural latex was used as the second layer in trial 8, and aqueous solution containing 25% natural latex was used as the second layer in trial 9. As can be seen, good raw adhesion performance was also achieved by only using the natural latex water-mixed chemical. The chemical referred to as natural latex is actually dissolved in water. 20% natural latex solution means that 20% by weight of the solution is natural latex solids and the rest is water. In Table 2, the target adhesion value is set as 100 and the raw adhesion value is given as a percentage of the target value.

Table 2 Comparison of the state of the art with the diluted natural latex composition at a laboratory scale

In the next study, large-scale operating trials were conducted. In this production, instead of the two-mouth dewebber system, the single-mouth dewebber system was used and the dipping was further kept on the fabric. The Dewebber system ensures that excess chemicals are removed from the textile material. In the two-mouth dewebber system, the chemical on the textile material is further vacuumed. In the single-mouth system, less vacuum is applied. For this reason, the rate of chemicals on the fabric increases. The adhesion performance is improved by increasing the chemical. In this production, process oven temperatures and process speed were optimized to ensure that the textile material is dried under the right conditions. After the first coating, the oven temperatures are gradually increased between 130-200°C. After the second coating, the fabric is passed through ovens at a temperature that will dry the fabric at the optimum level. This temperature is between 100-150°C.

Table 3 shows the results of different trials at operating scale as described above for the comparison of the raw adhesion values of textile materials obtained by using the second coating material containing diluted natural rubber of the present invention with the state of the art. As an example of the second layer coating composition consisting of diluted natural latex of the present invention, aqueous solution containing 20% natural latex was used as the second layer in trial 10, aqueous solution containing 25% natural latex was used as the second layer in trial 11, and aqueous solution containing 30% natural latex was used as the second layer in trial 12. As an example of the state of the art, RFL and Struktol LT 395C, which is rosin ester resin, were used as the second layer in trial 13. In Table 3, the target adhesion value is set as 100 and the raw adhesion value is given as a percentage of the target value.

Table 3 Comparison of the state of the art with the diluted natural latex composition at an operating scale

As can be seen, unlike the state of the art, the desired raw adhesion value was achieved by only diluting the natural latex to a certain extent, without RFL in the dipping solution used as the second layer. When different natural latex ratios were considered, it was observed that raw adhesion increased as the latex ratio increased. Here, it can be clearly seen that by changing the ratio of natural latex used within the scope of the invention, a higher level of raw adhesion can be achieved than with the chemicals in the state of the art.