Adhesive composition including ethylene/alpha-olefin copolymer

Abstract

The present invention provides an adhesive composition including an ethylene/alpha-olefin copolymer; and a tackifier, wherein the ethylene/alpha-olefin copolymer has narrow molecular weight distribution together with a low density and an ultra low molecular weight, minimized number of unsaturated functional groups, and particularly a small amount of vinylidene among the unsaturated functional groups, thereby showing excellent physical properties.

Claims

1. An adhesive composition comprising an ethylene/alpha-olefin copolymer; and a tackifier, wherein the ethylene/alpha-olefin copolymer satisfies the following conditions i) to iv): i) a viscosity: 6,000 cP to 40,000 cP, when measured at a temperature of 180° C., ii) a molecular weight distribution (MWD): 1.5 to 3.0, iii) a total number of unsaturated functional groups per 1000 carbon atoms: 0.8 or less, and iv) a R.sub.vd value according to the following Mathematical Equation 1: 0.3 or less: $\begin{array}{cc}{R}_{\mathrm{vd}}=\frac{\left[\mathrm{vinylidene}\right]}{\left[\mathrm{vinyl}\right]+\left[\mathrm{vinylene}\right]+\left[\mathrm{vinylidene}\right]}& \left[\mathrm{Mathematical}\mathrm{Equation}1\right]\end{array}$ in Mathematical Equation 1, the vinyl, vinylene and vinylidene mean the number of each functional group per 1000 carbon atoms, measured through nuclear magnetic spectroscopic analysis.

2. The adhesive composition according to claim 1, wherein the ethylene/alpha-olefin copolymer has a density of 0.85 to 0.89 g/cc, measured according to ASTM D-792.

3. The adhesive composition according to claim 1, wherein the ethylene/alpha-olefin copolymer has a weight average molecular weight (Mw) of 17,000 to 40,000 g/mol.

4. The adhesive composition according to claim 1, wherein the viscosity is 8,500 to 35,000 cP, when measured at a temperature of 180° C.

5. The adhesive composition according to claim 1, wherein the alpha-olefin comprises one or more selected from propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, or 1-eicocene.

6. The adhesive composition according to claim 1, wherein the alpha-olefin is comprised in an amount of from greater than 0 to 99 mol % or less with respect to a total weight of the ethylene/alpha-olefin copolymer.

7. The adhesive composition according to claim 1, wherein the ethylene/alpha-olefin copolymer further satisfies the following conditions v) to vii): v) a density: 0.85 to 0.89 g/cc, measured according to ASTM D-792, vi) a number average molecular weight (Mn): 9,000 to 25,000, and vii) a melt index (MI) at 190° C., 2.16 kg load by ASTM D1238: 200 to 1,300 dg/min.

8. The adhesive composition according to claim 1, wherein the tackifier is one or more selected from a modified C5 hydrocarbon resin, a styrenated teflon resin, a totally or partially hydrogenated C9 hydrocarbon resin, a hydrogenated alicyclic hydrocarbon resin, or a hydrogenated aromatic modified alicyclic hydrocarbon resin.

9. An article comprising a substrate coated with the adhesive composition according to claim 1.

10. The adhesive composition according to claim 1, wherein the ethylene/alpha-olefin copolymer has a crystallization temperature (Tc) of 45° C. to 60° C., and a melting temperature (Tm) of 60 to 80° C., wherein both the crystallization temperature and the melting temperature are measured by a differential scanning calorimetry (DSC).

11. The adhesive composition according to claim 1, wherein the tackifier is included in 5 parts by weight to 70 parts by weight with respect to 100 parts by weight of the adhesive composition, and the ethylene/alpha-olefin copolymer is included in 10 parts by weight to 50 parts by weight with respect to 100 parts by weight of the adhesive composition.

12. A method of preparing an ethylene/alpha-olefin copolymer, which satisfies the following conditions i) to iv): i) a viscosity: 6,000 cP to 40,000 cP, when measured at a temperature of 180° C., ii) a molecular weight distribution (MWD): 1.5 to 3.0, iii) a total number of unsaturated functional groups per 1000 carbon atoms: 0.8 or less, and iv) a R.sub.vd value according to the following Mathematical Equation 1: 0.3 or less: $\begin{array}{cc}{R}_{\mathrm{vd}}=\frac{\left[\mathrm{vinylidene}\right]}{\left[\mathrm{vinyl}\right]+\left[\mathrm{vinylene}\right]+\left[\mathrm{vinylidene}\right]}& \left[\mathrm{Mathematical}\mathrm{Equation}1\right]\end{array}$ in Mathematical Equation 1, the vinyl, vinylene and vinylidene mean the number of each functional group per 1000 carbon atoms, measured through nuclear magnetic spectroscopic analysis, the method comprising a step of polymerizing ethylene and an alpha-olefin-based monomer by injecting hydrogen in 45 to 100 cc/min in the presence of a catalyst composition including a transition metal compound of Formula 1: ##STR00006## wherein, R.sub.1 is hydrogen; alkyl of 1 to 20 carbon atoms; cycloalkyl of 3 to 20 carbon atoms; alkenyl of 2 to 20 carbon atoms; alkoxy of 1 to 20 carbon atoms; aryl of 6 to 20 carbon atoms; arylalkoxy of 7 to 20 carbon atoms; alkylaryl of 7 to 20 carbon atoms; or arylalkyl of 7 to 20 carbon atoms, R.sub.2a to R.sub.2e are each independently hydrogen; halogen; alkyl of 1 to 20 carbon atoms; cycloalkyl of 3 to 20 carbon atoms; alkenyl of 2 to 20 carbon atoms; alkoxy of 1 to 20 carbon atoms; or aryl of 6 to 20 carbon atoms, R.sub.3 is hydrogen; halogen; alkyl of 1 to 20 carbon atoms; cycloalkyl of 3 to 20 carbon atoms; alkenyl of 2 to 20 carbon atoms; aryl of 6 to 20 carbon atoms; alkylaryl of 6 to 20 carbon atoms; arylalkyl of 7 to 20 carbon atoms; alkyl amido of 1 to 20 carbon atoms; aryl amido of 6 to 20 carbon atoms; or phenyl which is substituted with one or more selected from the group consisting of halogen, alkyl of 1 to 20 carbon atoms, cycloalkyl of 3 to 20 carbon atoms, alkenyl of 2 to 20 carbon atoms, alkoxy of 1 to 20 carbon atoms and aryl of 6 to 20 carbon atoms, R.sub.4 to R.sub.9 are each independently hydrogen; silyl; alkyl of 1 to 20 carbon atoms; cycloalkyl of 3 to 20 carbon atoms; alkenyl of 2 to 20 carbon atoms; aryl of 6 to 20 carbon atoms; alkylaryl of 7 to 20 carbon atoms; arylalkyl of 7 to 20 carbon atoms; or a metalloid radical of a metal in group 14, which is substituted with hydrocarbyl of 1 to 20 carbon atoms; where among the R.sub.6 to R.sub.9, adjacent two or more are optionally connected with each other to form a ring, Q is Si or C, M is a transition metal in group 4, and X.sub.1 and X.sub.2 are each independently hydrogen; halogen; alkyl of 1 to 20 carbon atoms; cycloalkyl of 3 to 20 carbon atoms; alkenyl of 2 to 20 carbon atoms; aryl of 6 to 20 carbon atoms; alkylaryl of 7 to 20 carbon atoms; arylalkyl of 7 to 20 carbon atoms; alkylamino of 1 to 20 carbon atoms; or arylamino of 6 to 20 carbon atoms.

13. The method of preparing the ethylene/alpha-olefin copolymer according to claim 12, wherein the compound of Formula 1 comprises a compound represented by any one among the structures below: ##STR00007## ##STR00008##

14. The method of preparing the ethylene/alpha-olefin copolymer according to claim 12, wherein the catalyst composition further comprises a promoter for activating the transition metal compound of Formula 1.

15. The method of preparing the ethylene/alpha-olefin copolymer according to claim 14, wherein the promotor comprises an organometal compound including a metal in group 13.

16. The method of preparing the ethylene/alpha-olefin copolymer according to claim 14, wherein the promotor comprises one or more selected from a compound of the following Formula 2, a compound of the following Formula 3, or a compound of the following Formula 4:
R.sub.41—[Al(R.sub.42)—O].sub.n—R.sub.43  [Formula 2] in Formula 2, R.sub.41, R.sub.42 and R.sub.43 are each independently any one selected from hydrogen, halogen, a hydrocarbyl group of 1 to 20 carbon atoms, or a halogen-substituted hydrocarbyl group of 1 to 20 carbon atoms, and n is an integer of 2 or more,
D(R.sub.44).sub.3  [Formula 3] in Formula 3, D is aluminum or boron, and each R.sub.44 is each independently any one selected from halogen, a hydrocarbyl group of 1 to 20 carbon atoms, or a halogen-substituted hydrocarbyl group of 1 to 20 carbon atoms,
[L-H].sup.+[Z(A).sub.4].sup.− or [L].sup.+[Z(A).sub.4].sup.−  [Formula 4] in Formula 4, L is a neutral Lewis base or Brønsted base, H is a hydrogen atom, [L].sup.+ is a cationic Lewis acid, [L-H].sup.+ is a cationic Brønsted acid, Z is an element in group 13, and A is each independently a hydrocarbyl group of 1 to 20 carbon atoms, or a hydrocarbyloxy group of 1 to 20 carbon atoms, wherein the hydrocarbyl group or the hydrocarbyloxy group is unsubstituted or substituted with one or more substituents selected from halogen, a hydrocarbyloxy group of 1 to 20 carbon atoms, or a hydrocarbylsilyl group of 1 to 20 carbon atoms.

17. The method of preparing the ethylene/alpha-olefin copolymer according to claim 12, wherein the transitional metal compound of Formula 1 is in a supported state on a support, and a weight ratio of the transitional metal compound of Formula 1 to the support is 1:10 to 1:1,000.

18. The method of preparing the ethylene/alpha-olefin copolymer according to claim 17, wherein the support is silica, alumina, magnesia or a mixture thereof.

19. The method of preparing the ethylene/alpha-olefin copolymer according to claim 12, wherein the polymerization is performed at 80° C. to 200° C., and under a pressure of about 1 to about 100 kgf/cm.sup.2.

Description

MODE FOR CARRYING OUT THE INVENTION

Examples

(1) Hereinafter, preferred embodiments will be suggested to assist the understanding of the present invention.

(2) However, the embodiments are provided only for easy understanding of the present invention, and the contents of the present invention is not limited thereto.

Synthetic Example: Preparation of Transition Metal Compound

Step 1: Preparation of Ligand Compound (1a-1)

(3) To a 250 mL schlenk flask, 10 g (1.0 eq, 49.925 mmol) of 1,2-dimethyl-3H-benzo[b]cyclopenta[d]thiophene and 100 mL of THF were put, and 22 mL (1.1 eq, 54.918 mmol, 2.5 M in hexane) of n-BuLi was added thereto dropwisely at −30° C., followed by stirring at room temperature for 3 hours. A stirred Li-complex THF solution was cannulated into a schlenk flask containing 8.1 mL (1.0 eq, 49.925 mmol) of dichloro(methyl) (phenyl)silane and 70 mL of THF at −78° C., followed by stirring at room temperature overnight. After stirring, drying in vacuum was carried out and extraction with 100 ml of hexane was carried out.

(4) To 100 ml of an extracted chloro-1-(1,2-dimethyl-3H-benzo[b]cyclopenta[d]thiophene-3-yl)-1,1-(methyl) (phenyl)silane hexane solution, 42 mL (8 eq, 399.4 mmol) of t-BuNH.sub.2 was injected at room temperature, followed by stirring at room temperature overnight. After stirring, drying in vacuum was carried out and extraction with 150 ml of hexane was carried out. After drying the solvents, 13.36 g (68%, dr=1:1) of a yellow solid was obtained.

(5) ##STR00004##

(6) .sup.1H NMR (CDCl.sub.3, 500 MHz): δ 7.93 (t, 2H), 7.79 (d, 1H), 7.71 (d, 1H), 7.60 (d, 2H), 7.48 (d, 2H), 7.40-7.10 (m, 10H, aromatic), 3.62 (s, 1H), 3.60 (s, 1H), 2.28 (s, 6H), 2.09 (s, 3H), 1.76 (s, 3H), 1.12 (s, 18H), 0.23 (s, 3H), 0.13 (s, 3H)

Step 2: Preparation of Transition Metal Compound (1a)

(7) To a 100 mL schlenk flask, 4.93 g (12.575 mmol, 1.0 eq) of a ligand compound of Formula 1a-1 and 50 mL (0.2 M) of toluene were put and 10.3 mL (25.779 mmol, 2.05 eq, 2.5 M in hexane) of n-BuLi was added thereto dropwisely at −30° C., followed by stirring at room temperature overnight. After stirring, 12.6 mL (37.725 mmol, 3.0 eq, 3.0 M in diethyl ether) of MeMgBr was added thereto dropwisely, 13.2 mL (13.204 mmol, 1.05 eq, 1.0 M in toluene) of TiCl.sub.4 was put in order, followed by stirring at room temperature overnight. After stirring, drying in vacuum and extraction with 150 mL of hexane were carried out, the solvents were removed to 50 mL, and 4 mL (37.725 mmol, 3.0 eq) of DME was added dropwisely, followed by stirring at room temperature overnight. Again, drying in vacuum and extraction with 150 mL of hexane were carried out. After drying the solvents, 2.23 g (38%, dr=1:0.5) of a brown solid was obtained.

(8) ##STR00005##

(9) .sup.1H NMR (CDCl.sub.3, 500 MHz): δ 7.98 (d, 1H), 7.94 (d, 1H), 7.71 (t, 6H), 7.50-7.30 (10H), 2.66 (s, 3H), 2.61 (s, 3H), 2.15 (s, 3H), 1.62 (s, 9H), 1.56 (s, 9H), 1.53 (s, 3H), 0.93 (s, 3H), 0.31 (s, 3H), 0.58 (s, 3H), 0.51 (s, 3H), −0.26 (s, 3H), −0.39 (s, 3H)

Preparation of Ethylene/Alpha-Olefin Copolymer

Preparation Example 1

(10) Into a 1.5 L autoclave continuous process reactor, a hexane solvent (5.0 kg/h) and 1-octene (1.00 kg/h) were charged, and the top of the reactor was pre-heated to a temperature of 150° C. A triisobutylaluminum compound (0.05 mmol/min), the transition metal compound (1a) (0.40 μmol/min) prepared in the Synthetic Example as a catalyst, and a dimethylanilium tetrakis(pentafluorophenyl) borate promoter (1.20 μmol/min) were injected into the reactor at the same time. Then, into the autoclave reactor, ethylene (0.87 kg/h) and a hydrogen gas (50 cc/min) were injected and copolymerization reaction was continuously carried out while maintaining a pressure of 89 bar and a polymerization temperature of 125° C. for 60 minutes or more to prepare a copolymer.

(11) Then, a remaining ethylene gas was exhausted out and the copolymer-containing solution thus obtained was dried in a vacuum oven for 12 hours or more. The physical properties of the copolymer thus obtained were measured.

Preparation Examples 2 to 5 and Comparative Preparation Examples 1 to 7

(12) Polymers were prepared by carrying out the same method as in Preparation Example 1 except that the reactant materials were injected in amounts listed in Table 1 below.

(13) TABLE-US-00001 TABLE 1 Catalyst Polym- H.sub.2 injec- Promoter 1-C8 eri- injec- tion injection injec- zation tion amount amount tion TiBAl temper- amount (μmol/ (μmol/ amount (mmol/ ature (cc/ min) min) (kg/h) min) (° C.) min) Preparation 0.40 1.20 1.00 0.05 125 50 Example 1 Preparation 0.40 1.20 1.00 0.05 125 75 Example 2 Preparation 0.40 1.20 1.00 0.05 125 80 Example 3 Preparation 0.40 1.20 1.00 0.05 125 95 Example 4 Preparation 0.20 0.60 1.10 0.05 125 85 Example 5 Comparative 0.70 2.10 2.00 0.05 150 0 Preparation Example 1 Comparative 0.40 1.20 1.00 0.05 125 0 Preparation Example 2 Comparative 0.40 1.20 1.00 0.05 125 10 Preparation Example 3 Comparative 0.40 1.20 1.00 0.05 125 15 Preparation Example 4 Comparative 0.40 1.20 1.00 0.05 125 130 Preparation Example 5 Comparative 0.26 0.78 1.20 0.05 125 35 Preparation Example 6 Comparative 0.65 1.95 2.20 0.05 160 0 Preparation Example 7 * In Comparative Preparation Examples 6 and 7, [Me.sub.2Si(Me.sub.4C.sub.5)NtBu]Ti(CH.sub.3).sub.2 was used as a catalyst.

(14) With respect to the ethylene/alpha-olefin copolymers prepared in the Preparation Examples and the Comparative

(15) Preparation Examples, physical properties were measured according to the methods described below and are shown in Table 2.

(16) 1) Density (g/cm.sup.3): measured according to ASTM D-792.

(17) 2) Viscosity (cP): measured using a Brookfield RVDV3T viscometer and according to the method described below. In detail, 13 ml of a specimen was put in a specimen chamber and heated to 180° C. using Brookfield Thermosel. After the specimen was completely dissolved, a viscometer equipment was lowered to fix a spindle to the specimen chamber, the rotation speed of the spindle (SC-29 high temperature-melt spindle) was fixed to 20 rpm, and viscosity values were deciphered for 20 minutes or more, or until the value was stabilized, and a final value was recorded.

(18) 3) Viscosity change rate (%): measured using a Brookfield RVDV3T viscometer and according to the method described below. In detail, 13 ml of a specimen was put in a specimen chamber and heated to 180° C. using Brookfield

(19) Thermosel. After the specimen was completely dissolved, a viscometer equipment was lowered to fix a spindle to the specimen chamber, the rotation speed of the spindle (SC-29 high temperature-melt spindle) was fixed to 20 rpm, and viscosity values were recorded once per hour for 72 hours. A difference between an initial viscosity and a viscosity after 72 hours was converted into a percentage, and the viscosity change rate was calculated.

(20) For reference, the viscosity was too high or too low in Comparative Preparation Examples 1 to 5, and the measurement of the viscosity change rate using SC-29 high temperature-melt spindle (5000-450000 cP) was impossible.

(21) 4) Melting temperature (Tm, ° C.): The melting temperature of a polymer was measured using a differential scanning calorimeter (DSC, apparatus name: DSC 2920, manufacturer: TA instrument). Particularly, the polymer was heated to 150° C., kept for 5 minutes, and cooled to −100° C., and then, the temperature was elevated again. In this case, the elevating rate and decreasing rate of the temperature were controlled to 10° C./min, respectively. The maximum point of an endothermic peak measured in a second elevating section of the temperature was set to the melting temperature.

(22) 5) Crystallization temperature (Tc, ° C.): performed by the same method as that for measuring the melting temperature using DSC. From a curve represented while decreasing the temperature, the maximum point of an exothermic peak was set to crystallization temperature.

(23) 6) Weight average molecular weight (g/mol) and molecular weight distribution (MWD): a number average molecular weight (Mn) and a weight average molecular weight (Mw) were measured, respectively, by gel permeation chromatography (GPC, PL GPC220) under the conditions below, and molecular weight distribution was calculated through dividing the weight average molecular weight by the number average molecular weight: Column: PL Olexis Solvent: trichlorobenzene (TCB) Flow rate: 1.0 ml/min Specimen concentration: 1.0 mg/ml Injection amount: 200 μl Column temperature: 160° C. Detector: Agilent High Temperature RI detector Standard: Polystyrene (calibrated by cubic function)

(24) 7) Total number of unsaturated functional groups (per 1000 C): the numbers of vinyl, vinylene, and vinylidene per 1000 carbon atoms were measured from the NMR analysis results.

(25) In detail, first, in order to remove remaining 1-octene which may be present in a specimen, the polymer was prepared by reprecipitation prior to conducting NMR analysis. In detail, 1 g of the polymer was completely dissolved in chloroform of 70° C., and the polymer solution thus obtained was slowly poured into 300 ml of methanol while stirring to reprecipitate the polymer. The reprecipitated polymer was dried in vacuum at room temperature. The above-described process was repeated once more to obtain a polymer from which remaining 1-octene was removed.

(26) 30 mg of the specimen of the polymer obtained above was dissolved in 1 ml of a chloroform-d (w/TMS) solution. Measurement was performed 16 times at room temperature with an acquisition time of 2 seconds and a pulse angle of 45°, using an Agilent 500 MHz NMR equipment. Then, the TMS peak in 1H NMR was calibrated to 0 ppm, a CH.sub.3-related peak (triplet) of 1-octene at 0.88 ppm and a CH.sub.2-related peak (broad singlet) of ethylene at 1.26 ppm were confirmed, respectively. An integration value of the CH.sub.3 peak was calibrated to 3 to calculate the contents. The numbers of vinyl, vinylene and vinylidene could be calculated based on the integration values of each functional group in 4.5-6.0 ppm region. For reference, the viscosity of Comparative Example 6 below was too low viscosity, and was not measured.

(27) 8) R.sub.vd: R.sub.vd value was calculated according to the following Mathematical Equation 1 from the numbers of vinyl, vinylene and vinylidene, measured through the NMR analysis:

(28) $\begin{array}{cc}{R}_{\mathrm{vd}}-\frac{\left[\mathrm{vinylidene}\right]}{\left[\mathrm{vinyl}\right]+\left[\mathrm{vinylene}\right]+\left[\mathrm{vinylidene}\right]}& \left[\mathrm{Mathematical}\mathrm{Equation}1\right]\end{array}$

(29) (in Mathematical Equation 1, vinyl, vinylene and vinylidene mean the number of each functional group per 1000 carbon atoms, measured through nuclear magnetic spectroscopic analysis).

(30) TABLE-US-00002 TABLE 2 Number of unsaturated Viscosity functional groups (per change 1000 C) Molecular Density Tc/Tm Viscosity rate Total weight (g/cc) (° C.) (cP) (%) amount vinyl vinylene vinylidene R.sub.vd Mw distribution Preparation 0.873 50.6/66.5 35000 18 0.40 0.05 0.27 0.08 0.20 34900 1.98 Example 1 Preparation 0.875 52.0/68.1 17000 15 0.35 0.04 0.24 0.07 0.20 24400 1.96 Example 2 Preparation 0.876 52.3/68.9 13500 14 0.32 0.03 0.22 0.07 0.22 22400 1.98 Example 3 Preparation 0.877 53.2/69.7 8500 11 0.29 0.03 0.20 0.06 0.21 19500 1.77 Example 4 Preparation 0.875 52.2/68.3 17000 12 0.30 0.02 0.21 0.07 0.18 24500 1.96 Example 5 Comparative 0.872 49.7/66.0 >50000 N/A 1.36 0.20 0.78 0.39 0.29 46800 2.14 Preparation Example 1 Comparative 0.874 51.5/67.6 >50000 N/A 0.54 0.06 0.38 0.10 0.19 75400 2.08 Preparation Example 2 Comparative 0.874 51.3/67.8 >50000 N/A 0.45 0.04 0.32 0.09 0.20 57700 2.09 Preparation Example 3 Comparative 0.873 50.5/66.3 >50000 N/A 0.42 0.04 0.29 0.09 0.21 48700 2.08 Preparation Example 4 Comparative 0.879 55.7/72.7 3500 N/A 0.29 — — — — 14600 1.97 Preparation Example 5 Comparative 0.876 56.1/73.2 13900 22 0.32 0.03 0.10 0.20 0.63 22800 1.94 Preparation Example 6 Comparative 0.875 55.3/73.1 15800 41 1.38 0.19 0.79 0.40 0.29 26700 2.24 Preparation Example 7 In Table 2, “—” means not measured, and “N/A” means unmeasurable.

Preparation of Adhesive Composition

Example 1

(31) An adhesive composition including 40 wt % of the copolymer of Preparation Example 2 as an ethylene/alpha-olefin copolymer, 40 wt % of SUKOREZ® SU-110S (Kolon Industries, Inc.) as a tackifier, and 20 wt % of SASOLWAX H.sub.1 (SASOL) as a plasticizer, was prepared.

Examples 2 to 4 and Comparative Examples 1 to 4

(32) Adhesive compositions were prepared according to the same method as in Example 1 except for changing the kinds and amounts of the ethylene/alpha-olefin copolymer, tackifier and plasticizer, as listed in Table 3 below.

(33) TABLE-US-00003 TABLE 3 Ethylene/alpha-olefin copolymer Preparation Preparation Comparative Comparative tackifier Example Example Preparation Preparation SU- H- plasticizer 2 3 Example 6 Example 7 100S 100W SasolH1 Example 1 40 40 20 Example 2 40 40 20 Example 3 40 40 20 Example 4 40 40 20 Comparative 40 40 20 Example 1 Comparative 40 40 20 Example 2 Comparative 40 40 20 Example 3 Comparative 40 40 20 Example 4 * Eastotac H-100W (Eastman Chemical Company)

(34) In case of Comparative Preparation Examples 1 to 4, the viscosity was too high, and in case of Comparative Preparation Example 5, the viscosity was too low, and the application to the adhesive composition of the present invention was difficult. Accordingly, by using the copolymers of Comparative Preparation Examples 6 and 7, which had a viscosity in a similar range as the copolymers of the Preparation Examples of the present invention, the adhesive compositions of Comparative Examples 1 to 4 were constituted.

Experimental Examples

(35) Physical properties on the adhesive compositions of the Examples and the Comparative Examples were measured by the methods below, and are shown in Table 4.

(36) 1) Viscosity change rate (%): measured using a Brookfield RVDV3T viscometer and according to the method described below. In detail, 13 ml of a specimen was put in a specimen chamber and heated to 180° C. using Brookfield Thermosel. After the specimen was completely dissolved, a viscometer equipment was lowered to fix a spindle to the specimen chamber, the rotation speed of the spindle (SC-29 high temperature-melt spindle) was fixed to 20 rpm, and viscosity values were recorded once per hour for 144 hours. A difference between an initial viscosity and a viscosity after 144 hours was converted into a percentage, and the viscosity change rate was calculated.

(37) 2) Heat resistant discoloration (YI): measured using a forced convection oven by JEIO TECH (OF-22) according to the method below. In detail, 100 g of an adhesive composition which was prepared after cut within 2.5 mm×2.5 mm, was weighed. The specimen thus weighed was put in a 250 ml, heat resistant beaker and heated at 140° C. in a vacuum oven three or four times for 10 to 20 minutes to remove remaining bubbles. The mouth of the beaker was sealed with an aluminum foil, the temperature of a convection oven was set to 180° C., and the beaker was continuously heated for 72 hours. Then, a specimen was formed into a thickness of 2 mm and a YI value was measured. YI used was an average value after measuring three or more different points of the specimen.

(38) TABLE-US-00004 TABLE 4 Viscosity Heat resistant change discoloration rate (%) (YI) Example 1 9 59 Example 2 9 46 Example 3 8 61 Example 4 9 45 Comparative 17 76 Example 1 Comparative 18 54 Example 2 Comparative 13 67 Example 3 Comparative 13 48 Example 4

(39) Referring to Table 4, a case of the adhesive composition according to the present invention showed a little viscosity change according to time and excellent long-period properties. In addition, discoloration degree was a little even after standing for a long time at a high temperature, and it could be confirmed that stability at a high temperature was excellent.

(40) Particularly, the adhesive composition of the present invention showed the viscosity change rate of less than 10% after 144 hours, which was markedly lower than the Comparative Examples.

(41) In addition, in the adhesive composition of the present invention when compared with the Comparative Examples using the same tackifier, it was confirmed that Examples 1 and 3 showed less heat resistant discoloration degree when compared with Comparative Examples 1 and 3, and Examples 2 and 4 showed less heat resistant discoloration degree when compared with Comparative Examples 2 and 4. Accordingly, it could be confirmed that the adhesive composition of the present invention has stability at a high temperature.

(42) As described above, since the adhesive composition of the present invention includes an ethylene/alpha-olefin copolymer having total number of unsaturated functional groups per 1,000 carbon atoms of 0.8 or less, a R.sub.vd value of 0.5 or less, and a small amount ratio of vinylidene, viscosity change rate according to time is insignificant and excellent long-period properties may be shown, and also, stability at a high temperature may be improved.