HOT MELT ADHESIVE

Abstract

Disclosed is a hot melt adhesive comprising: (A) a metallocene based propylene homopolymer, (B) a metallocene based ethylene/-olefin copolymer, (C) a tackifier resin, and (D) a plasticizer, wherein the plasticizer (D) comprises (D1) an oil and (D2) at least one polymer selected from polybutene, polybutadiene, polyisobutylene, and polyisoprene. This hot melt adhesive has an initial adhesive strength enough to enable a pressure sensitive adhesion body to stick easily on a member, thus making it possible to firmly hold the pressure sensitive adhesion body on the member. The hot melt adhesive is also excellent in releasability, thus causing no adhesive residue on the member when the pressure sensitive adhesion body is peeled from the member.

Claims

1: A hot melt adhesive comprising: (A) a metallocene based propylene homopolymer, (B) a metallocene based ethylene/-olefin copolymer, (C) a tackifier resin, and (D) a plasticizer, wherein the plasticizer (D) comprises (D1) an oil and (D2) at least one polymer selected from polybutene, polybutadiene, polyisobutylene, and polyisoprene.

2: The hot melt adhesive according to claim 1, wherein the oil (D1) comprises a naphthene oil.

3: The hot melt adhesive according to claim 1, wherein the polymer (D2) comprises polybutene.

4: The hot melt adhesive according to claim 1, which comprises the polymer (D2) in an amount of 5 to 90 parts by weight based on 100 parts by weight of the total weight of the oil (D1) and the polymer (D2).

5: The hot melt adhesive according to claim 1, wherein the metallocene based propylene homopolymer (A) has a melting point of 100 C. or lower.

Description

EXAMPLES

[0151] The present invention will be described for the purpose of describing the present invention in more detail and specific manner by way of Examples. These are exemplary of the present invention and are not to be considered as limiting.

[0152] Components for blending a hot melt adhesive are shown below.

[0153] (A) Metallocene Based Propylene Homopolymer

[0154] (A1) Metallocene based propylene homopolymer (melting point of 75 C., weight average molecular weight of 45,000) (L-MODU X400S (trade name) manufactured by Idemitsu Kosan Co., Ltd.)

[0155] (A2) Metallocene based propylene homopolymer (melting point of 80 C., weight average molecular weight of 70,000) (L-MODU X600S (trade name) manufactured by Idemitsu Kosan Co., Ltd.)

[0156] (A3) Metallocene based propylene homopolymer (melting point of 90 C., weight average molecular weight of 130,000) (L-MODU X900S (trade name) manufactured by Idemitsu Kosan Co., Ltd.)

[0157] (A4) Ziegler-Natta based propylene homopolymer (melting point of 145 C.) (Eastoflex P1010 (trade name) manufactured by Eastman Chemical Company)

[0158] (A5) Metallocene based polyethylene homopolymer (melting point of 115 C.) (EXCEREX 07500 (trade name) manufactured by Mitsui Chemicals Inc.)

[0159] (B) Metallocene Based Ethylene/-Olefin Copolymer

[0160] (B1) Metallocene based ethylene/propylene copolymer (melt index of 20 (g/10 min: 230 C.)) (Vistamaxx 6202 (trade name) manufactured by Exxon Mobil Corporation)

[0161] (B2) Metallocene based ethylene/octene copolymer (melt index of 15 (g/10 min: 190 C.)) (INFUSE 9807 (trade name) manufactured by The Dow Chemical Company)

[0162] (B3) Metallocene based ethylene/octene copolymer (melt index of 500 (g/10 min: 190 C.)) (AFFINITY GA1950 (trade name) manufactured by The Dow Chemical Company)

[0163] (B4) Styrene-butadiene block copolymer (Asaprene T-438 (trade name) manufactured by Asahi Kasei Chemicals Corporation)

[0164] (B5) Polylactic acid resin (Biopolymer 4060D (trade name) manufactured by Nature Works LLC)

[0165] (C) Tackifier Resin

[0166] (C1) Hydrogenated dicyclopentadiene based resin (T-REZ HA103 (trade name) manufactured by JXTG Nippon Oil & Energy Corporation)

[0167] (C2) Petroleum based hydrocarbon resin (LUHOREZ A1100S (trade name) manufactured by ZIBO QILU YIXI LUHUA CHEMICAL)

[0168] (D) Plasticizer

[0169] (D1) Oil

[0170] (D1-1) Naphthene oil (weight average molecular weight of 400) (KN40102 (trade name) manufactured by PetroChina Company)

[0171] (D1-2) Paraffin oil (weight average molecular weight of 500) (Diana Frecia S32 (trade name) manufactured by Idemitsu Kosan Co., Ltd.)

[0172] (D2) Polymer selected from polybutene, polybutadiene, polyisobutylene, and polyisoprene

[0173] (D2-1) Polybutene (weight average molecular weight of 3,500) (Nisseki Polybutene HV-300 (trade name) manufactured by Nippon Oil Corporation, Ltd.)

[0174] (D2-2) Polybutadiene (weight average molecular weight of 4,000) (NISSO-PB B-1,000 (trade name) manufactured by Nippon Soda Co., Ltd.)

[0175] (D2-3) Hydrogenated polybutadiene (weight average molecular weight of 50,000) (NISSO-PB BI-2000 (trade name) manufactured by Nippon Soda Co., Ltd.)

[0176] (D2-4) Polyisobutylene (weight average molecular weight of 56,000) (HIMOL 4H (trade name) manufactured by JXTG Nippon Oil & Energy Corporation)

[0177] (D2-5) Polyisoprene (weight average molecular weight of 66,000) (Kurapren LIR-50 (trade name) manufactured by KURARAY CO., LTD.)

[0178] (E) Wax

[0179] (E1) Maleic acid modified wax (LICOCENE MA6252TP (trade name) manufactured by Clariant Corporation)

[0180] (E2) Solid paraffin (Paraffin Wax-155 (trade name) manufactured by NIPPON SEIRO CO., LTD.)

[0181] (F) Antioxidant

[0182] (F1) Hindered phenol based antioxidant (ADK STAB AO-60 (trade name) manufactured by ADEKA Corporation)

[0183] Using a universal stirrer, components (A) to (F) were blended according to the formulations shown in Tables 1 and 2, and then melt-blended at 150 C. for 2 hours to prepare hot melt adhesives of Examples 1 to 13 and Comparative Examples 1 to 10.

TABLE-US-00001 TABLE 1 Examples 1 2 3 3 4 5 6 7 8 9 10 11 12 13 A A1 34 24 30 30 34 25 35 35 35 35 25 25 A2 35 A3 35 B B1 53 50 46 46 53 50 50 50 50 50 50 50 B2 50 B3 50 C C1 100 60 90 90 120 60 100 100 100 100 100 100 90 100 C2 30 30 D1 D1-1 85 75 45 10 95 80 80 80 80 75 75 75 75 D1-2 80 D2 D2-1 15 25 55 90 5 20 25 25 25 25 D2-2 20 D2-3 20 D2-4 20 D2-5 20 E E1 2 2 E2 0.1 F F1 3 3 3 3 3 3 3 3 3 3 4 4 4 4 Glass transition 8 0 2 8 10 10 4 6 9 8 9 10 10 8 temperature ( C.) Melt viscosityt 8,400 9,000 11,500 12,000 7,400 5,500 7,200 7,400 12700 11,000 53,00 15,500 2,100 1,800 a 160 C. (mPa .Math. s) Loop tack A A A A A A A A B B A B B A (initial adhesive strength) SUS Peel A A A B B B B B B B A B B B strength (holding force) Ad- A A A A A A A A A A A A A B hesive residue Glass Peel A A A B B B A A B B A A A A strength (holding force) Ad- A A A A A A B B A B A A B B hesive residue PP Peel A A A B A B A A A B B B B B strength (holding force) Ad- A A A A B B A B A B A B B B hesive residue PE Peel A A A B B B A B B B B B A A strength (holding force) Ad- A A A A A A B A A B A A B B hesive residue

TABLE-US-00002 TABLE 2 Comparative Examples 1 2 3 4 5 6 7 8 9 10 A A1 35 34 34 100 40 40 40 A2 30 A4 40 A5 40 B B1 22 53 53 100 60 60 60 B4 60 B5 60 C C1 87 130 130 135 135 135 135 135 135 C2 31 D1 D1-1 100 80 80 80 75 75 75 75 D1-2 100 D2 D2-1 100 20 20 20 25 25 25 25 E E1 3 3 3 F F1 4 4 4 4 4 4 4 4 4 4 Glass transition 11 16 10 8 7 5 15 15 13 temperature ( C.) Melt viscosity at 2,400 700 23,000 6,300 3,000 2,000 7,500 3,700 2,200 160 C. (mPa .Math. s) Loop tack (initial B A D C C D A D A adhesive strength) SUS Peel strength B A A B D D A D C (holding force) Adhesive residue B D A A A A Glass Peel strength A C B D C D A A C (holding force) Adhesive residue C D B A D C B C PP Peel strength C B B B A D A B A (holding force) Adhesive residue D D B B D D D C D PE Peel strength B D B B A D B D D (holding force) Adhesive residue D A A D A

[0184] All numerical values with respect to the compositions (formulations) of the hot melt adhesives shown in Table 1 and Table 2 are numerical values in terms of parts by weight. Regarding each of the hot melt adhesives (Examples and Comparative Examples), glass transition temperature (Tg), melt viscosity at 160 C., tack, peel strength, and adhesive residue were evaluated. Outlines of each evaluation will be described below.

[0185] <Glass Transition Temperature>

[0186] Using a dynamic viscoelasticity measuring instrument (Rheometer AR-G2 (trade name) manufactured by TA Instruments Japan Inc.), a glass transition temperature was measured. Each of the hot melt adhesives was heated by a jig of the instrument and then formed into a disk shape having a diameter of 25 mm and a thickness of 1,500 m. Using a parallel plate made of stainless steel, an angular rate was fixed at 10 rad/s and the glass transition temperature was measured in a temperature sweep mode at a rate of 5 C./min by heating in a range of 25 C. to 150 C. In a temperature range of a softening point or lower, a loss tangent Tan (G/G) represented by a ratio of a loss modulus (G) to a storage modulus (G) is measured. The loss tangent Tan was plotted as a function of a temperature. The temperature indicating a peak top of an obtained peak was read and regarded as a glass transition temperature of the hot melt adhesive.

[0187] <Measurement of Melt Viscosity (160 C.)>

[0188] In accordance with the method B defined in JAI7-1991, a viscosity at 160 C. of each of the hot melt adhesives was measured. In the measurement, a Brookfield viscometer and a No. 27 rotor were used.

[0189] <Tack (Initial Adhesive Strength)>

[0190] Each of the hot melt adhesives was applied on a 50 m thick PET film (50 cm in length24 cm in width) to form a 50 m thick pressure sensitive adhesive layer. This PET film was formed (or cut) into a size measuring 2.5 cm10 cm to obtain specimens. Each specimen was wound in a loop form such that a surface (surface to be coated with an adhesive) of the pressure sensitive adhesive layer faces outside, and then the wound specimen was brought into contact with a member (PE sheet) at 20 C. at a rate of 300 mm/min to thereby stick the specimen to the member. Then, the specimen was peeled from the PE sheet at a rate of 300 mm/min to thereby measure the strength at the time of peeling, followed by evaluation of tack.

[0191] A: Loop tack exceeds 1,500 (g/25 mm).

[0192] B: Loop tack is 1,000 (g/25 mm) or more and less than 1,500 (g/25 mm).

[0193] C: Loop tack is 500 (g/25 mm) or more and less than 1,000 (g/25 mm).

[0194] D: Loop tack is less than 500 (g/25 mm).

[0195] <Peel Strength (Holding Force)>

[0196] A specimen fabricated under a condition which is the same as that in the above-mentioned tack was stuck on each of members (1) to (4) mentioned below such that a surface (surface to be coated with an adhesive) of the pressure sensitive layer faces the member, and then a load was applied by one reciprocal motion using a 200 g of a rubber roller to obtain samples for evaluation. Four kinds of materials such as (1) SUS304, (2) glass, (3) PE, and (4) PP were used as the member.

[0197] Each sample for evaluation was aged in an atmosphere at 23 C. under 65% R.H. for 18 hours or more, and then a peel test was carried out in the atmosphere at 23 C. under 65% R.H. The peel test was carried out by Autograph AGS-J manufactured by Shimadzu Corporation under the following conditions.

[0198] Peel direction: Direction which is the same as that of movement of the base material (MD) direction.

[0199] Distance between chucks: 20 mm

[0200] Peel speed: 300 mm/min

[0201] Peel length: 50 mm

[0202] Analysis method: average of testing force

[0203] With respect to each of the hot melt adhesives (Examples and Comparative Examples), at least three samples were fabricated and then measured three times. The peel strength was determined by the obtained average. The peel strength was evaluated by the following criteria.

(1) SUS

[0204] A: Peel strength is 10 N or more.

[0205] B: Peel strength is 5 N or more and less than 10 N.

[0206] C: Peel strength is 2 N or more and less than 5 N.

[0207] D: Peel strength is less than 2 N.

(2) Glass

[0208] A: Peel strength is 10 N or more.

[0209] B: Peel strength is 5 N or more and less than 10 N.

[0210] C: Peel strength is 2 N or more and less than 5 N.

[0211] D: Peel strength is less than 2 N.

(3) PE

[0212] A: Peel strength is 20 N or more.

[0213] B: Peel strength is 10 N or more and less than 20 N.

[0214] C: Peel strength is 2 N or more and less than 10 N.

[0215] D: Peel strength is less than 2 N.

(4) PP

[0216] A: Peel strength is 10 N or more.

[0217] B: Peel strength is 5 N or more and less than 10 N.

[0218] C: Peel strength is 2 N or more and less than 5 N.

[0219] D: Peel strength is less than 2 N.

[0220] <Adhesive Residue (or Adhesive Deposit)>

[0221] After the measurement of the peel strength, the presence of adhesive residue (whether the adhesive remains on the peeling surface or not) was evaluated by immediately touching the peeling surface of the peeling member with a finger. The evaluation criteria of adhesive residue are shown below.

[0222] A: No adhesive residue

[0223] B: Slight adhesive residue

[0224] C: A little adhesive residue

[0225] D: Obvious adhesive residue

[0226] -: Exempt from evaluation because of peel strength of less than 2 N

[0227] As shown in Table 1, each of the hot melt adhesives of Examples 1 to 13 is excellent in balance among initial adhesive strength, holding force, and releasability. More specifically, each of the hot melt adhesives is excellent in initial adhesive strength and holding force and hardly causes adhesive residue, thus proving that each of the hot melt adhesives of Examples is useful as a pressure sensitive adhesive.

[0228] Whereas, as shown in Table 2, each of the hot melt adhesives of Comparative Examples 1 to 10 does not comprise any one of the components (A) to (C), (D1), and (D2) and is therefore significantly inferior in any one of the performances as compared with the hot melt adhesives of Examples. Namely, the hot melt adhesives have performance rated as D. The hot melt adhesives of Comparative Examples are not excellent in balance among initial adhesive strength, holding force, and releasability.

[0229] These results revealed that the hot melt adhesives comprising components (A) to (C), (D1), and (D2) enable a pressure sensitive adhesion body to stick easily and exhibit higher holding force on a member, and hardly cause adhesive residue, and are therefore effective as a pressure sensitive adhesive.

INDUSTRIAL APPLICABILITY

[0230] The present invention can provide a hot melt adhesive which is useful as a pressure sensitive adhesive, and a pressure sensitive adhesion (or adhesive) body coated with the hot melt adhesive.