ADHESIVE COMPOSITION, RUBBER REINFORCING MATERIAL AND ARTICLES

Abstract

The present application relates to an adhesive composition comprising at least naturally occurring acid, a nitrogen compound and a latex; and a rubber reinforcing material and an article comprising the same.

Claims

1. An adhesive composition comprising: (a) 1.0 to 5.0% by weight of a naturally occurring acid; (b) 0.01 to 4.0% by weight of a nitrogen compound; (c) 0.01 to 4.0% by weight of a basic material; and (d) 5.0 to 50% by weight of a latex, wherein the adhesive composition comprises, as a basic material, 0.01 to 1.5% by weight of sodium hydroxide (NaOH) as a first basic material, and 0.01 to 2.5% by weight of a second basic material different from the first basic material (wherein, the % by weight of the components (a) to (d) means the solid content occupied by each component in the adhesive composition, and the nitrogen compound and the basic material are different from each other).

2. The adhesive composition of claim 1, wherein the naturally occurring acid is a naturally occurring phenol.

3. The adhesive composition of claim 1, wherein the naturally occurring acid is a naturally occurring tannic acid.

4. The adhesive composition of claim 1, comprising 3.0 to 50.0 parts by weight of the naturally occurring acid based on 100 parts by weight of the latex.

5. The adhesive composition of claim 1, comprising 0.3 to 25.0 parts by weight of the nitrogen compound based on 100 parts by weight of the latex.

6. The adhesive composition of claim 1, comprising 0.1 to 20.0 parts by weight of the basic material based on 100 parts by weight of the latex.

7. The adhesive composition of claim 1, further comprising a solvent.

8. The adhesive composition of claim 7, comprising 30% by weight or more of the solvent based on 100% by weight of the total content of the adhesive composition.

9. The adhesive composition of claim 7, wherein the solvent comprises water.

10. The adhesive composition of claim 1, wherein the nitrogen compound comprises one or more selected from the group consisting of piperazine, piperidine, pyridine, pyrimidine, pyrrolidine, pyrrole, imidazole, indole, aniline, histidine, tryptophan and hexamine.

11. The adhesive composition of claim 1, wherein the second basic material comprises one or more selected from the group consisting of sodium carbonate (Na.sub.2CO.sub.3), potassium hydroxide (KOH), magnesium hydroxide (Mg(OH).sub.2) and ammonia (NH.sub.3).

12. The adhesive composition of claim 1, further comprising a condensate of the naturally occurring acid and the nitrogen compound.

13. An adhesive composition, comprising: 5.0 to 50% by weight of a latex; a condensate of 1.0 to 5.0% by weight of a naturally occurring acid and 0.01 to 4.0% by weight of a nitrogen compound; and 0.01 to 4.0% by weight of a basic material, wherein the adhesive composition comprises, as a basic material, 0.01 to 1.5% by weight of sodium hydroxide (NaOH) as a first basic material, and 0.01 to 2.5% by weight of a second basic material different from the first basic material, and wherein the adhesive composition has a pH within the range of 9.0 to 11.0 (wherein, the nitrogen compound and the basic material are different from each other).

14. The adhesive composition of claim 13, wherein the naturally occurring acid comprises a naturally occurring phenol.

15. The adhesive composition of claim 13, wherein the naturally occurring acid is a naturally occurring tannic acid.

16. The adhesive composition of claim 13, wherein the nitrogen compound comprises one or more selected from the group consisting of piperazine, piperidine, pyridine, pyrimidine, pyrrolidine, pyrrole, imidazole, indole, aniline, histidine, tryptophan and hexamine.

17. The adhesive composition of claim 13, wherein the second basic material comprises one or more selected from the group consisting of sodium carbonate (Na.sub.2CO.sub.3), potassium hydroxide (KOH), magnesium hydroxide (Mg(OH).sub.2) and ammonia (NH.sub.3).

18. A rubber reinforcing material comprising a raw cord containing a fiber; and a coating layer formed on the raw cord, wherein the coating layer comprises the adhesive composition according to claim 1.

19. A rubber reinforcing material comprising a raw cord containing a fiber; and a coating layer formed on the raw cord, wherein the coating layer comprises 100 parts by weight of a latex, 3.0 to 25.0 parts by weight of a naturally occurring acid, 0.3 to 25.0 parts by weight of a nitrogen compound, and 0.1 to 15.0 parts by weight of a basic material, and wherein the coating layer comprises 0.1 to 9.0 parts by weight of sodium hydroxide (NaOH) as a first basic material and 0.1 to 14.0 parts by weight of a second basic material different from the first basic material, based on 100 parts by weight of the latex.

20. A tire comprising a rubber reinforcing material according to claim 18.

Description

DESCRIPTION OF DRAWINGS

[0135] FIG. 1 is a graph showing the wavelength analysis results of the naturally occurring tannic acid (TA1) used in Examples, the synthetic tannic acid (manufactured by Sigma-Aldrich) (TA2), and the RF condensate (divalent phenol, Kolon Industries HiRENOL KOSABOND-R50) (RF) according to infrared spectroscopy. A peak observed in the vicinity of a commonly identified wavenumber of about 1600 to 1620 cm.sup.1 is a peak for an aromatic ring. RF condensate and tannic acid commonly have a benzene ring, but RF is known as a hazardous substance. On the other hand, tannic acid is a non-hazardous substance except direct inhalation of dust. On the other hand, in the case of a naturally occurring tannic acid and a synthetic tannic acid, it is confirmed that they are distinguished according to the presence or absence of a peak near a wavenumber of about 1700 cm.sup.1. The peak near the wavenumber of 1700 cm.sup.1 is a peak appearing in the CO bond. This peak is considered to be due to the CO bond generated in the process of artificially synthesizing tannic acid. That is, it can be seen that synthetic tannic acid and naturally occurring tannic acid are distinguished from each other in that the CO-containing unit is smaller in naturally occurring tannic acid.

[0136] FIG. 2 schematically shows a cross section of a tire cord that can be manufactured by using an adhesive composition according to an exemplary embodiment of the present application.

[0137] FIG. 3 schematically shows a preparation process of a tire cord.

[0138] FIG. 4 schematically shows a cross section of a tire that can be prepared by using an adhesive composition according to an exemplary embodiment of the present application.

[0139] FIG. 5a and FIG. 5b schematically explain the direction of the force applied to each sample in Experiments 1 and 2 related to the evaluation of the adhesive force of the adhesive composition of the present application. FIG. 5a is the direction of the force applied in the H-test of Experiment 1, and FIG. 5b is the direction of the force applied in the Peel-test of Experiment 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0140] Hereinafter, actions and effects of the invention will be described in more detail with reference to specific examples of the invention. However, these examples are for illustrative purposes only, and the scope of the invention is not limited thereby in any way.

Preparation of Compositions of Examples and Comparative Examples

[0141] The compositions of Examples and Comparative Examples were prepared by performing the mixing and stirring under the same conditions except that that the content (wt. %) ratio was the same as in Table 1 below. Specifically, each component was mixed and stirred at room temperature (about 20 C.) for 24 hours. As a result, condensation polymerization of tannic acid and hexamine was performed in the presence of basic materials.

[0142] Table 1 relates to Examples, and Table 2 relates to Comparative Examples. For reference, each component (solvent, NaOH, tannic acid, ammonia, hexamine, and latex) listed in Table below was prepared in a dispersed state in water and then mixed. and the pH of the composition after mixing ranges from 9.0 to 11.0.

TABLE-US-00001 TABLE 1 Adhesive compositions of Examples Basic Basic Nitrogen Solid material.sup.2) Acid material compound.sup.5) content Example Solvent.sup.1) (NaOH) component.sup.3) (NH.sub.3).sup.4) (HEXAMINE) Latex.sup.6) (TSC) 1 75.62 0.05 3.60 0.03 0.20 20.50 24.38 2 75.57 0.10 3.60 0.03 0.20 20.50 24.43 3 75.52 0.15 3.60 0.03 0.20 20.50 24.48 4 75.47 0.20 3.60 0.03 0.20 20.50 24.53 5 75.42 0.25 3.60 0.03 0.20 20.50 24.58 6 75.37 0.30 3.60 0.03 0.20 20.50 24.63 7 77.72 0.05 1.50 0.03 0.20 20.50 22.28 8 76.97 0.30 2.00 0.03 0.20 20.50 23.03 9 76.47 0.30 2.50 0.03 0.20 20.50 23.53 10 75.97 0.30 3.00 0.03 0.20 20.50 24.03 11 75.47 0.30 3.50 0.03 0.20 20.50 24.53 12 74.97 0.30 4.00 0.03 0.20 20.50 25.03 13 74.47 0.30 4.50 0.03 0.20 20.50 25.53 14 73.97 0.30 5.00 0.03 0.20 20.50 26.03 15 75.40 0.05 3.60 0.25 0.20 20.50 24.60 16 75.50 0.30 3.00 0.50 0.20 20.50 24.50 17 75.25 0.30 3.00 0.75 0.20 20.50 24.75 18 75.00 0.30 3.00 1.00 0.20 20.50 25.00 19 74.75 0.30 3.00 1.25 0.20 20.50 25.25 20 74.50 0.30 3.00 1.50 0.20 20.50 25.50 21 74.25 0.30 3.00 1.75 0.20 20.50 25.75 22 74.00 0.30 3.00 2.00 0.20 20.50 26.00 Unit: wt. % .sup.1)Solvent (non-solid component): The remaining component except the solid component, which is distilled water. .sup.2)Basic material: A NaOH product (a state dispersed in water at a concentration of 20 wt. %:mixed concentration of 80 wt. % of water + 20 wt. % of NaOH) provided by Duksan General Chemical Co. Ltd. was used. .sup.3)Acid component: Naturally occurring tannic acid (a state dispersed in water at a concentration of 50 wt. %:mixed concentration of 50 wt. % of water + 50 wt. % of tannic acid) provided by Duksan General Chemicals Co., Ltd. was used. .sup.4)Ammonia: Ammonia dissolved in water at a concentration of 25 wt. % (mixed concentration of 75 wt. % of water + 25 wt. % of ammonia) was used. .sup.5)Nitrogen compound: Hexamine (a state dispersed in water at a concentration of 5 wt. %:mixed concentration of 95 wt. % of water + 5 wt. % of hexamine) produced by Sigma-Aldrich was used. .sup.6)Latex: 0653 VP Latex from Croslene (a state dispersed in water at a concentration of 40.5 wt. %:mixed concentration of 59.5 wt. % of water + 40.5 wt. % of latex) was used.

TABLE-US-00002 TABLE 2 Adhesive compositions of Comparative Examples Basic Basic Nitrogen Solid Comparative material.sup.2) Acid material compound .sup.4) content Example Solvent .sup.1) (NaOH) component.sup.3) (NH.sub.3) (HEXAMINE) Latex .sup.5) Resorcinol.sup.6) (TSC) 1 76.27 0.00 3.00 0.03 0.20 20.50 0.00 23.73 2 74.27 2.00 3.00 0.03 0.20 20.50 0.00 25.73 3 78.97 0.30 0.00 0.03 0.20 20.50 0.00 21.03 4 72.97 0.30 6.00 0.03 0.20 20.50 0.00 27.03 5 76.00 0.30 3.00 0.00 0.20 20.50 0.00 24.00 6 73.00 0.30 3.00 3.00 0.20 20.50 0.00 27.00 7 76.17 0.30 3.00 0.03 0.00 20.50 0.00 23.83 8 71.17 0.30 3.00 0.03 5.00 20.50 0.00 28.83 9 77.97 0.30 0.00 0.03 0.20 20.50 1.00 22.03 10 76.97 0.30 0.00 0.03 0.20 20.50 2.00 23.03 11 77.97 0.30 0.00 0.03 0.20 20.50 1.00 22.03 12 76.97 0.30 0.00 0.03 0.20 20.50 2.00 23.03 Unit: wt. % .sup.1) Solvent (non-solid component): It is the remaining component except the solid component, which is distilled water. .sup.2)Basic material: A NaOH product (a state dispersed in water at a concentration of 20 wt. %:mixed concentration of 80 wt. % of water + 20 wt. % of NaOH) provided by Duksan General Chemical Co. Ltd. was used. .sup.3)Acid component: Naturally occurring tannic acid (a state dispersed in water at a concentration of 50 wt. %:mixed concentration of 50 wt. % of water + 50 wt. % of tannic acid) provided by Duksan General Chemicals Co., Ltd. was used. .sup.4) Nitrogen compound: Hexamine (a state dispersed in water at a concentration of 5 wt. %:mixed concentration of 95 wt. % of water + 5 wt. % of hexamine) produced by Sigma-Aldrich was used. .sup.5) Latex: 0653 VP Latex from Croslene (a state dispersed in water at a concentration of 40.5 wt. %:mixed concentration of 59.5 wt. % of water + 40.5 wt. % of latex) was used. .sup.6)Resorcinol: Resorcinol dispersed in water at a concentration of 50 wt. % (mixed concentration of 50 wt. % water + 50 wt. % resorcinol) was used.

Preparation Example

[0143] 2 Strands of primarily twisted yarns (Z-direction) having a twist number of 360 TPM using a polyester yarn were prepared, and then the 2 strands of primarily twisted yarns were secondarily twisted (S-direction) together with a twist number of 360 TPM to prepare a plied twisted yarn (1650 dtex/2 ply). The plied twisted yarn thus prepared was used as a raw cord.

[0144] The polyester raw cord was dipped in the first coating liquid, and then treated for about 1 minute at a drying temperature of 150 C. and a curing temperature of 240 C., respectively, to form a first coating layer and thereby, a reactive active group was imparted to the cord. At this time, the first coating liquid was prepared by mixing an epoxy compound and an isocyanate compound in a weight ratio of about 1:2, together with 97 wt. % of demineralized water.

[0145] Then, the raw cord on which the first coating layer was formed was dipped in the second coating liquid (adhesive compositions prepared in Examples and Comparative Examples), dried and cured to form the second coating layer. At this time, drying and curing were performed for about 1 minute at a drying temperature of 150 C. and a curing temperature of 235 C., respectively. The dipping step of the first coating liquid and the dipping step of the second coating liquid were performed continuously, and the tension condition at this time was 0.5 g/d. A tire cord was prepared in the form of a dipped cord through the above process.

[0146] The prepared tire cord was used in Experiments 1 and 2 below.

Experiment 1: H-Test (Pull-Out Test)

[0147] The adhesive force of the tire cord prepared as described above was evaluated by measuring the Pull-out adhesive force according to ASTM D4776, and the results are recorded in Table 3 below.

[0148] Specifically, a rubber sheet with a thickness of 0.6 mm, one strand of cord sheet (prepared in Preparation Example, and a rubber sheet with a thickness of 0.6 mm were sequentially laminated, and vulcanized at 170 C. under a pressure of 50 kg/cm.sup.2 for 15 minutes to prepare a sample. For the prepared specimen, a peeling test was performed at 25 C. at a speed of 125 mm/min using a universal material tester (Instron) to measure the adhesive force of the tire cord to the carcass layer, and the relative magnitudes of the measured adhesive forces are described. At this time, the adhesive force is the average value of three times the load generated during peeling, and the values of the adhesive layer formed by the adhesive composition of Example 1 were normalized and relatively compared.

[0149] In the case of this H-Test, the peeling test was performed in the vertical direction after laminating and vulcanizing the rubber sheet, whereas in the case of the PEEL test described below, then the peel test was performed in the horizontal direction after laminating and vulcanizing the rubber sheet. There is a difference between the two in this respect.

[0150] Through such an experiment, it is possible to compare and confirm the adhesive force and durability of the cord depending on the direction of the force applied to the tire cord.

Experiment 2: PEEL Test

[0151] In order to evaluate the adhesive force per unit area to the tire cords prepared as described above, the adhesive force evaluation was performed in accordance with ASTM D4393, and the results are listed in Table 3 below.

[0152] Specifically, a rubber sheet with a thickness of 0.6 mm, a cord sheet (a cord sheet containing the cord prepared in Preparation Example was used, but in accordance with ASTM D4393, the weft yarn was removed, and then the evaluation proceeded with a warp yarn in which the number of warp yarns was 25.4 EPI (end per inch)), a rubber sheet with a thickness of 0.6 mm, and a cord sheet (a cord sheet containing the cord prepared in Preparation Example was used, but in accordance with ASTM D4393, the weft yarn was removed, and then the evaluation proceeded with a warp yarn in which the number of warp yarns was 25.4 EPI (end per inch)), and a rubber sheet with a thickness of 0.6 mm were sequentially laminated, and vulcanized at 170 C. under a pressure of 60 kg/cm.sup.2 for 15 minutes to prepare a sample. And, the sample was cut to prepare a specimen having a width of 1 inch.

[0153] For the prepared sample, a peeling test was performed at 25 C. at a speed of 125 mm/min using a universal material tester (Instron) to measure the adhesive force of the tire cord to the carcass layer, and the relative magnitudes of the measured adhesive forces were described. At this time, the average value of three times the load generated during peeling was calculated as the adhesive force, and the values of the adhesive layer formed by the adhesive composition of Example 1 were normalized and relatively compared.

Experiment 3: Dynamic Adhesion Test (Bending Fatigue Test)

[0154] In regard to fatigue evaluation for adhesive compositions, the fatigue evaluation was performed for the prepared tire cord in accordance with ASTM D430, and the results are recorded in Table 3 below.

[0155] Specifically, a rubber sheet with a thickness of 3.2 mm, a cord sheet (prepared in Preparation Example), a rubber sheet with a thickness of 0.5 mm, a cord sheet (prepared in Preparation Example), and a rubber sheet with a thickness of 3.2 mm were sequentially stacked to prepare a sample, and then, it was vulcanized at a pressure of 60 kg/cm.sup.2 at 170 C. for 15 minutes to manufacture a sample. And, the sample was cut to prepare a specimen having a width of 1 inch.

[0156] While conducting a fatigue test on the prepared specimen at a speed of 180 rpm at 100 C. using a bending fatigue tester, the adhesive force after fatigue of the tire cord was measured. The calculation formula of the adhesive force after fatigue is as follows:

[00001]$\begin{array}{cc}\mathrm{Adhesion}\mathrm{after}\mathrm{fatigue}\left(\%\right)=\left(\mathrm{Adhesive}\mathrm{force}\mathrm{of}\mathrm{fatigued}\mathrm{portion}/\mathrm{Adhesive}\mathrm{force}\mathrm{of}\mathrm{non}-\mathrm{fatigued}\mathrm{portion}\right)100& \left[\mathrm{Calculation}\mathrm{Formula}\right]\end{array}$

[0157] At this time, the fatigued portion and the non-fatigued portion can be distinguished through a notation that allows each portion to be distinguished before proceeding with the fatigue evaluation as described above. Alternatively, it is possible to distinguish between a fatigued portion and a non-fatigued portion with the naked eye even without the above notation.

[0158] The adhesive force after fatigue is the average value of three measurements, and the values measured with the adhesive composition of Example 1 were normalized and relatively compared.

Experiment 4: Tire Simulation Evaluation

[0159] A rubber sheet with a thickness of 1.6 mm, a cord sheet (prepared in Preparation Example), and a rubber sheet with a thickness of 0.5 mm were sequentially laminated, and vulcanized at 160 C. for 20 minutes at a pressure of 60 kg/cm.sup.2 to prepare a sample. Then, the sample was cut to prepare a specimen having a width of 1 inch by 10 cm. For the prepared specimen, tensile strength was measured when the specimen was pulled and cut at a speed of 125 mm/min at 25 C. using a universal testing machine (Instron). At this time, the tensile strength is the average value of three times the load generated during cutting, and the values measured in the adhesive composition of Example 1 were normalized and relatively compared.

[0160] In Experiments 1-3, peeling evaluation (adhesive force evaluation) was performed after vulcanization, but in the case of Experiment 4, the tensile strength of the rubber specimen itself containing the tire cord was tested instead of peeling evaluation. That is, unlike the evaluation of adhesive force in Experiments 1-3, Experiment 4 can be regarded as a simulation experiment for estimating the durability of a tire including a cord.

TABLE-US-00003 TABLE 3 Dynamic Tire Simulation H-test Peel test Adhesion Test Evaluation Example 1 100 100 100 100 Example 2 100 91 90 91 Example 3 99 95 87 87 Example 4 90 89 88 92 Example 5 97 91 88 90 Example 6 93 95 86 91 Example 7 90 97 85 91 Example 8 97 97 88 91 Example 9 91 95 89 90 Example 10 89 100 88 91 Example 11 91 88 90 89 Example 12 97 97 88 90 Example 13 92 100 86 89 Example 14 96 92 89 85 Example 15 94 91 85 90 Example 16 93 93 90 88 Example 17 90 92 88 88 Example 18 96 90 88 93 Example 19 97 96 87 94 Example 20 98 89 89 98 Example 21 98 88 89 86 Example 22 97 88 89 95 Comparative 70 66 45 55 Example 1 Comparative 53 40 58 47 Example 2 Comparative 56 56 42 47 Example 3 Comparative 71 63 55 52 Example 4 Comparative 73 55 67 55 Example 5 Comparative 60 65 62 44 Example 6 Comparative 62 51 41 58 Example 7 Comparative 72 57 56 65 Example 8 Comparative 63 55 60 71 Example 9 Comparative 68 47 53 70 Example 10 Comparative 74 67 52 40 Example 11 Comparative 71 42 52 59 Example 12

DESCRIPTION OF SYMBOLS

[0161] 10: raw cord [0162] 11: primarily twisted yarn [0163] 12: primarily twisted yarn [0164] 20: coating layer [0165] 21: first coating layer [0166] 21: first coating liquid [0167] 22: second coating layer [0168] 22: second coating liquid [0169] 30: tire cord [0170] 100: first winder [0171] 200: first coating tank [0172] 300: first drying device [0173] 400: second coating tank [0174] 500: second drying device [0175] 600: second winder [0176] 1000: tread [0177] 2000: shoulder [0178] 3000: sidewall [0179] 4000: cap ply [0180] 5000: belt [0181] 6000: body fly or carcass [0182] 7000: inner liner [0183] 8000: apex [0184] 9000: bead