ADHESIVE COMPOSITION FOR TIRE CORD, TIRE CORD, AND TIRE

Abstract

This invention relates to an adhesive composition for a tire cord including: an epoxy compound; latex; an alicyclic polyurethane resin having a weight average molecular weight (Mw) of 250,000 to 350,000; an amine compound; and water, a tire cord including an adhesive layer formed form the adhesive composition, and a tire including the tire cord.

Claims

1. An adhesive composition for a tire cord comprising: an epoxy compound; latex; an alicyclic polyurethane resin having weight average molecular weight (Mw) of 250,000 to 350,000; an amine compound; and water.

2. The adhesive composition for tire cord according to claim 1, wherein the alicyclic polyurethane resin having weight average molecular weight (Mw) of 250,000 to 350,000 comprises a reaction product between a polyisocyanate comprising one or more alicyclic groups having a carbon number of 4 to 30 and a polyol.

3. The adhesive composition for tire cord according to claim 1, wherein the alicyclic polyurethane resin is a water-dispersed alicyclic polyurethane resin formed from an alicyclic polyurethane ionomers.

4. The adhesive composition for tire cord according to claim 1, wherein the alicyclic polyurethane resin comprises 1 to 20 mol % of parts derived from one or more compounds selected form the group consisting of dimethylol butanoic acid and dimethylol propionic acid.

5. The adhesive composition for tire cord according to claim 1, wherein viscosity measured using a Ubbelohde viscometer at room temperature is in the range of 2.50 to 2.85.

6. The adhesive composition for tire cord according to claim 1, wherein the composition comprises 0.5 to 10 wt % of an alicyclic polyurethane resin having a weight average molecular weight (Mw) of 250,000 to 350,000.

7. The adhesive composition for tire cord according to claim 6, wherein the composition comprises: 0.1 to 10 wt % of an epoxy compound; 1 to 30 wt % of latex; 0.5 to 10 wt % of an alicyclic polyurethane resin having weight average molecular weight (Mw) of 250,000 to 350,000; 0.1 to 10 wt % of an amine compound; and 50 to 95 wt % of water.

8. The adhesive composition for a tire cord according to claim 1, wherein the amine compound comprises an amine compound having a chain structure.

9. The adhesive composition for tire cord according to claim 1, wherein the adhesive composition for a tire cord further comprises one or more cross-linking agents selected from the group consisting of an isocyanate-based compound, an aziridine-based compound, and a metal chelate compound.

10. The adhesive composition for tire cord according to claim 1, wherein the adhesive composition for a tire cord comprises 50 wt % or more of water.

11. Tire cord comprising: a fiber substrate; and an adhesive layer formed on the fiber substrate, and formed from the adhesive composition of claim 1.

12. A tire cord comprising: a fiber substrate; and an adhesive layer formed on the fiber substrate, and comprising: an epoxy compound; latex; an alicyclic polyurethane resin having a weight average molecular weight (Mw) of 250,000 to 350,000; and an amine compound.

13. The tire cord according to claim 12, wherein the alicyclic polyurethane resin having a weight average molecular weight (Mw) of 250,000 to 350,000 comprises a reaction product between polyisocyanate comprising one or more alicyclic groups having a carbon number of 4 to 30 and a polyol.

14. The tire cord according to claim 12, wherein the alicyclic polyurethane resin comprises 1 to 20 mol % of parts derived from one or more compounds selected from the group consisting of dimethylol butanoic acid and dimethylol propionic acid.

15. The tire cord according to claim 12, wherein the fiber substrate is a raw cord comprising a polyester fiber.

16. A tire comprising the tire cord of claim 12.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0094] FIG. 1 is a schematic drawing showing an Ubbelohde viscometer used in Experimental Example 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0095] This invention will be explained in more detail in the following examples. However, these examples are presented only for illustration of the invention, and the scope of the invention is not limited thereby.

Examples and Comparative Examples: Preparation of Adhesive Composition for Tire Cord and Tire Cord

Example 1

[0096] (1) Synthesis of Water-Dispersed Polyurethane Resin

[0097] At the mole ratio described in the following Table 1, polyester polyol (weight average molecular weight: 2000), diol(1,6-hexanediol), and dimethylol butanoic acid (DMBA) were introduced, and mixed at 75±5° C. and atmospheric pressure for 4 hours.

[0098] And, at the mole ratio described in the following Table 1, 4,4′-dicyclohexylmethane diisocyanate (H.sub.12MDI) was added to the mixture, and reacted for 2 hours to prepare an alicyclic polyurethane prepolymer.

[0099] The reaction temperature of the prepolymer prepared above was lowered to 60° C., and a neutralizing agent (triethanolamine; TEA) was introduced in a solvent (acetone) to disperse. Herein, a stirrer was used for dispersion, and RPM of the stirrer was maintained at 1000 to 1500. After the dispersion was completed, the prepolymer was decompressed to remove acetone.

[0100] Into the neutralized prepolymer, distilled water was introduced such that the solid content became 60%. And, a chain extender (ethylene diamine; EDA) was added to prepare water-dispersed alicyclic polyurethane (weight average molecular weight: 308,000 g/mol).

[0101] (2) Preparation of Adhesive Compositions for Tire Cord

[0102] The components were mixed at the content ratio (wt %) as described in the following Table 4, and stirred at a temperature of about 20° C. for 24 hours to prepare each composition of the examples and Comparative examples.

[0103] (3) Preparation of Tire Cord

[0104] 2 strands of first twist yarns (Z-direction) (111, 112) with the twist number of 360 TPM were prepared using polyester yarn, and then, the two strands of first twist yarns (111, 112) were secondarily twisted together at the twist number of 360 TPM to prepare a ply yarn (1650 dtex/2 ply). The ply yarn thus prepared was used as a raw cord (110).

[0105] The raw cord (110) consisting of polyester was immersed in the first coating solution, and then treated at a drying temperature of 150° C. and a curing temperature of 240° C., respectively for 1 minute, to form a first coating layer (211), thus providing reaction active groups to the raw cord (110).

[0106] And then, in order to provide an adhesive composition to the raw cord (110) on which the first coating layer (211) was formed, the raw cord (110) on which the first coating layer (211) was formed was immersed in the second coating solution, then dried and cured. Herein, drying and curing were conducted by treating at a drying temperature of 150° C. and a curing temperature of 235° C., respectively, for 1 minute. The first coating solution immersion process and the second coating solution immersion process were continuously conducted, wherein tension was 0.5 g/d. Thereby, tire cord (201) was prepared in the form of dipper cord.

Examples 2 to 10

[0107] (1) Synthesis of Waster-Dispersed Polyurethane Resins

[0108] Water-dispersed alicyclic polyurethane was prepared by the same method as Example 1, except that the mole ratio of components used were changed as described in the following Table 1 or Table 2.

[0109] (2) Preparation of Adhesive Compositions for Tire Cord

[0110] The components were mixed at the content ratio (wt %) as described in the following Table 4 or Table 5, and stirred at a temperature of about 20° C. for 24 hours to prepare each composition.

[0111] (3) Preparation of Tire Cord

[0112] Tire cords were prepared by the same method as Example 1, except that the adhesive compositions for a tire cord were changed.

Comparative Examples 1 to 5

[0113] (1) Synthesis of Water-Dispersed Polyurethane Resins

[0114] Water-dispersed alicyclic polyurethane was prepared by the same method as Example 1, except that the mole ratio of the components used were changed as described in the following Table 3.

[0115] Herein, the weight average molecular weights of the water-dispersed alicyclic polyurethane resins respectively used in Comparatives Example 1 to 4 are as described in Table 3, and in Comparative Example 5, methylene diphenyl diisocyanate (MDI) aromatic diisocyanate was used instead of 4,4′-dicyclohexylmethane diisocyanate.

[0116] (2) Preparation of Adhesive Compositions for Tire Cord

[0117] The components were mixed at the content ratio (wt %) as described in the following Table 6, and stirred at a temperature of about 20° C. for 24 hours to prepare each composition.

[0118] (3) Preparation of Tire Cords

[0119] Tire cords were prepared by the same method as Example 1, except that the adhesive compositions for a tire cord were changed.

TABLE-US-00001 TABLE 1 (unit: Example Example Example Example Example mole ratio) 1 2 3 4 5 (A) Polyester 1 0.5 2 1 1 polyol (B) Diol 0.2 0.2 0.2 1 2 (C) DMBA 0.8 0.8 0.8 0.8 0.8 (D) H.sub.12MDI 2 2 2 2 2 (E) EDA 1 1 1 1 1 (F) TEA 7 7 7 7 7 Mw (g/mol) 308000 286000 346000 316000 322000

TABLE-US-00002 TABLE 2 (unit: Example Example Example Example Example mole ratio) 6 7 8 9 10 (A) Polyester 1 1 1 1 1 polyol (B) Diol 6 8 0.2 0.2 0.2 (C) DMBA 0.8 0.8 3 0.8 0.8 (D) H.sub.12MDI 2 2 2 2 2 (E) EDA 1 1 1 4 1 (F) TEA 7 7 7 7 5 Mw (g/mol) 337000 342000 299000 319000 299000

TABLE-US-00003 TABLE 3 Compar- Compar- Compar- Compar- Compar- (unit: ative ative ative ative ative mole ratio) Example 1 Example 2 Example 3 Example 4 Example 5 (A) Polyester 0.1 2.5 1 1 1 polyol (B) Diol 0.2 0.2 0 12 0.2 (C) DMBA 0.8 0.8 0.8 0.8 0.8 (D) H.sub.12MDI 2 2 2 2 — (D) MDI — — — — 2 (E) EDA 1 1 1 1 1 (F) TEA 7 7 7 7 7 Mw (g/mol) 231000 364000 217000 379000 315000

TABLE-US-00004 TABLE 4 Example Example Example Example Example (unit: wt %) 1 2 3 4 5 (A) latex 14.7 14.7 14.7 14.7 14.7 (B) water- 1.5 1.5 1.5 1.5 1.5 dispersed polyurethane (C) amine 1.8 1.8 1.8 1.8 1.8 compound (D) chain 0.4 0.4 0.4 0.4 0.4 extender (E) epoxy 1.7 1.7 1.7 1.7 1.7 compound (F) isocy- 3.4 3.4 3.4 3.4 3.4 anate (G) solvent 76.5 76.5 76.5 76.5 76.5 TSC 23.5 23.5 23.5 23.5 23.5

TABLE-US-00005 TABLE 5 Example Example Example Example Example (unit: wt %) 6 7 8 9 10 (A) latex 14.7 14.7 14.7 14.7 14.7 (B) water- 1.5 1.5 1.5 1.5 1.5 dispersed polyurethane (C) amine 1.8 1.8 1.8 1.8 1.8 compound (D) chain 0.4 0.4 0.4 0.4 0.4 extender (E) epoxy 1.7 1.7 1.7 1.7 1.7 compound (F) isocy- 3.4 3.4 3.4 3.4 3.4 anate (G) solvent 76.5 76.5 76.5 76.5 76.5 TSC 23.5 23.5 23.5 23.5 23.5

TABLE-US-00006 TABLE 6 Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative (unit: wt %) Example 1 Example 2 Example 3 Example 4 Example 5 (A) latex 14.7 14.7 14.7 14.7 14.7 (B) water- 1.5 1.5 1.5 1.5 1.5 dispersed polyurethane (C) amine 1.8 1.8 1.8 1.8 1.8 compound (D) chain 0.4 0.4 0.4 0.4 0.4 extender (E) epoxy 1.7 1.7 1.7 1.7 1.7 compound (F) isocy- 3.4 3.4 3.4 3.4 3.4 anate (G) solvent 76.5 76.5 76.5 76.5 76.5 TSC 23.5 23.5 23.5 23.5 23.5

[0120] <Explanations of Tables 4 to 6>

[0121] (A) latex: VP latex 0653 from Closlen

[0122] (C) amine compound: Acrawax™ C Dispersion from Lonza

[0123] (D) chain extender: Piperazine

[0124] (E) epoxy compound: EX614B (Sorbitol Polyglycidyl Ether, Epoxy content: 167 g/eq, Viscosity (mPa s): 21,200) from NAGASE

[0125] (F) isocyanate: IL-6 from EMS

[0126] (G) solvent: Demineralized water

[0127] TSC: Total Solid Contents

EXPERIMENTAL EXAMPLES

Experimental Example 1: Measurement of Viscosities of the Compositions of Examples and Comparative Examples

[0128] The viscosity of each composition of the examples and comparative examples prepared above was measured at room temperature (about 25° C.) using an Ubbelohde viscometer.

[0129] The composition was left in a constant temperature water tank (about 25° C.) for 30 minutes, and then measured using the Ubbelohde viscometer. Specifically, through the following process, a certain amount of demineralized water was put in the Ubbelohde viscometer and the viscosity property of demineralized water was measured, and the viscosity property of the composition was measured by the same method, and then relative viscosity was calculated based on the viscosity property of the demineralized water already measured.

[0130] The specific measurement method of viscosity is as follows, and the measurement results are shown in Table 7.

[0131] (1) A sample (composition or demineralized water) was introduced into the A tube of the Ubbelohde viscometer.

[0132] (2) After setting a constant temperature water tank at 25° C., it is fixed so that the C part is immersed in the water tank, and left for 30 minutes.

[0133] (3) Using a pipette filler, the sample was positioned to the middle of the C part.

[0134] (4) The sample was flowed down, and a time from when the liquid surface of the sample passes through the upper gradation of B until the liquid surface of the sample passes through the lower gradation of B is measured.

[0135] (5) The measured time is applied to the relative viscosity calculation formula to calculate relative viscosity.

[0136] <Relative Viscosity Calculation Formula>

[0137] T1/T0

[0138] T1: a time from when the composition passes through the upper gradation of B until the composition passes through the lower gradation of B

[0139] T0: a time from when demineralized water passes through the upper gradation of B until demineralized water passes through the lower gradation of B

Experimental Example 2: Evaluation of Adhesive Strength

[0140] For each tire cord prepared in the examples and Comparative examples, in order to evaluate adhesive strength per unit area, adhesive peel strength of the tire cord was measured according to ASTM D4393. Specifically, a rubber sheet with a thickness of 0.6 mm, a cord ply, and a rubber sheet with a thickness of 0.6 mm were sequentially stacked to prepare a specimen, and then, it was vulcanized at the pressure of 60 kg/cm.sup.2 at 170° C. for 15 minutes to manufacture a sample.

[0141] And then, the vulcanized sample was cut to prepare a specimen having a width of 1 inch. For the prepared specimen, peel strength was tested at 25° C., at a speed of 125 mm/min, using a universal testing machine (Instron), thus measuring the adhesive strength of the tire cord. Herein, the average value of load generated during peeling was assessed as adhesive strength. The evaluation of adhesive strength was progressed, and reported in the following Table 7.

Experimental Example 3: Evaluation of Thermal Fatigue Resistance

[0142] For each tire cord prepared in the examples and comparative examples, fatigue resistance of each composition of the examples and comparative examples was measured.

[0143] Specifically, a rubber sheet with a thickness of 0.6 mm, a cord ply, a rubber sheet with a thickness of 0.6 mm, a cord ply, and a rubber sheet with a thickness of 0.6 mm were sequentially stacked to prepare a specimen, 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 vulcanized sample was cut to prepare a specimen having a width of 1 inch. The fatigue of the prepared specimen can be evaluated by the adhesive strengths of the rubber compound and tire cord for the unflexed part and flexed part of the tire cord pad specimen, and observation of the interface.

[0144] In a fatigue tester, a specimen having a width of 1 inch was attached, and then preheated at 100° C. for 30 minutes. And then, tester conditions of 100,000 cycles at 180 rpm and load of 60 kg were established, and a 1 inch Flexing Roller was used. After the fatigue evaluation was finished, it was taken out of the tester and left at room temperature for 12 hours, and then a peel strength test was progressed at 25° C., 125 mm/min, using a universal testing machine(Instron). Thermal fatigue resistance was measured according to the following Formula 1, and the results are shown in the following Table 7.

Fatigue (%)=(measurement results of adhesive strength for flexed part)*100/(measurement result of adhesive strength for unflexed part)  [Formula 1]

TABLE-US-00007 TABLE 7 Thermal fatigue Viscosity Adhesive strength resistance (RV) (%) (%) Example 1 2.71 100 100 Example 2 2.64 97 100 Example 3 2.82 97 98 Example 4 2.73 100 99 Example 5 2.76 100 95 Example 6 2.79 100 95 Example 7 2.81 100 99 Example 8 2.74 100 100 Example 9 2.54 100 97 Example 10 2.60 99 98 Comparative 2.41 75 72 Example 1 Comparative 2.88 75 79 Example 2 Comparative 2.44 72 81 Example 3 Comparative 2.89 76 80 Example 4 Comparative 2.92 77 79 Example5

[0145] As shown in Table 7, it was confirmed that the adhesive compositions for the tire cord of the examples have viscosities in the range of 2.50 to 2.85, and when applied, can improve adhesive strength of a tire cord to a carcass layer, and secure excellent heat resistant adhesive strength and thermal fatigue resistance.

[0146] To the contrary, it was confirmed that when the adhesive compositions for tire cord of the comparative examples are applied, sufficient adhesive strength of the tire cord to a carcass layer is not secured, and heat resistant adhesive strength and thermal fatigue resistance are relatively low.