Hot melt adhesive for polyolefin films

Abstract

A hot-melt adhesive composition is disclosed. The hot melt adhesive comprises a) 25 to 95 wt %, preferably 50 to 85 wt % of at least one polyolefin-based polymer; b) 1 to 75 wt %, preferably 1 to 40 wt % of at least one tackifying resin; c) 0 to 15 wt % of at least one plasticizer; and d) 0 to 30 wt % of at least one additive and/or adjuvant selected from among stabilizers, adhesion promoters, fillers or pigments, waxes, and/or other polymers or combinations thereof,
characterized in that the at least one polyolefin-based polymer is a mixture of: a1) at least one first polyolefin-based polymer with a molecular weight M.sub.n of <10,000 g/mol in a quantity of 20 to 80 wt % with respect to the total quantity of polyolefin-based polymer, and a2) at least one second polyolefin-based polymer with a molecular weight M.sub.n of >10,000 g/mol in a quantity of 20 to 80 wt % with respect to the total quantity of polyolefin-based polymer. The adhesive is particularly useful for gluing polyolefin films, woven fabrics, or nonwoven fabrics. Also, methods for manufacturing packaging and fabric with the hot-melt adhesive above are disclosed.

Claims

1. A hot-melt adhesive consisting of: a) 25 to 95 wt % of a mixture of atactic polyolefin-based polymers of a1) 20 to 80 wt %, based on the mixture of polyolefin-based polymer, of a first atactic poly-α-olefin, which is an (i) ethylene/α-olefin with propene, 1-butene, 1-hexene, or 1-octene comonomer; or (ii) propylene/α-olefin with ethylene, 1-butene, 1-hexene, or 1-octene comonomer; having a molecular weight M.sub.n of <10,000 g/mol and a first glass transition temperature, and a2) 20 to 80 wt %, based on the mixture of polyolefin-based polymer, of a second atactic poly-α-olefin, which is an (i) ethylene/α-olefin with propene, 1-butene, 1-hexene, or 1-octene comonomer; or (ii) propylene/α-olefin with ethylene, 1-butene, 1-hexene, or 1-octene comonomer; having a molecular weight M.sub.n of >10,000 g/mol and a second glass transition temperature; b) 1 to 75 wt % of at least one tackifying resin; c) 0 to 15 wt % of at least one poly(iso)butylene having a molecular weight M.sub.w of less than 5,000 g/mol and free of naphthenic oils; and d) 0 to 30 wt % of at least one additive and/or adjuvant selected from stabilizers, adhesion promoters, fillers or pigments, waxes, or combinations thereof wherein the hot-melt adhesive has a viscosity range of 5,000 to 11,300 mPas, measured at 160° C. with a Brookfield CAP, spindle 27 and wherein the hot-melt adhesive has a softening point of 70-87.9° C. as measured in accordance with ASTM E 28.

2. The hot-melt adhesive as set forth in claim 1, wherein, the tackifying resin is a natural resin based on colophony resin or tall oil resin.

3. The hot-melt adhesive as set forth in claim 1, wherein, the tackifying resin is a fully or partially hydrated hydrocarbon resin, which is a cycloaliphatic resin, an aromatically modified resin, a polyterpene, a terpene phenolic resin, a 1,3-pentadiene resin, a cyclopentadiene resin, a 2-methyl-2-butene copolymer, or a derivative thereof.

4. The hot-melt adhesive as set forth in claim 1, wherein, in that the at least one additive and/or the adjuvant is a stabilizer.

Description

EXAMPLES

Example 1: Adhesive Formulation

(1) In the following, the term “hydrocarbon resin” is also referred to as “HC resin.”

(2) The glass transition temperature T.sub.g was determined according to DIN EN 1427.

(3) The melt viscosity was determined according to DIN 53019.

(4) The molecular weight M.sub.n was determined according to DIN 55672, as described above.

(5) Adhesive compositions were prepared which contained the following components in relation to the composition:

(6) TABLE-US-00001 Formulation 1: Poly-α-olefin (M.sub.n 5,000 g/mol; T.sub.g 96° C.; 70.0 wt % melt viscosity 2,500 mPas) Poly-α-olefin (M.sub.n 18,100 g/mol; T.sub.g 107° C.; 15.0 wt % melt viscosity 50,000 mPas) Escorez 5400 (DownMobil Chemical),  5.0 wt % cycloaliphatic HC resin Polybut 10 (Productos Uhpon), polyisobutylene  9.5 wt % Irganox 1010 (BASF SE), antioxidant  0.5 wt %

(7) The product obtained in this way exhibited very good adhesion on polyolefin-based bag material in conjunction with a very high level of cohesion.

(8) TABLE-US-00002 Formulation 2: Poly-α-olefin (M.sub.n 5,000 g/mol; T.sub.g 96° C.; 70.0 wt % melt viscosity 2,500 mPas) Poly-α-olefin (M.sub.n 18,100 g/mol; T.sub.g 107° C.; 15.0 wt % melt viscosity 50,000 mPas) Sylvatac RE 85 (Arizona Chemical), colophony  5.0 wt % glycerol ester Polybut 10 (Productos Uhpon) polyisobutylene  9.5 wt % Irganox 1010 (BASF SE), antioxidant  0.5 wt %

(9) The product obtained in this way had even greater adhesion than formulation 1.

(10) TABLE-US-00003 Formulation 3: Poly-α-olefin (M.sub.n 5,000 g/mol; T.sub.g 96° C.; 15.0 wt % melt viscosity 2,500 mPas) Poly-α-olefin (M.sub.n 18,100 g/mol; T.sub.g 107° C.; 40.0 wt % melt viscosity 50,000 mPas) Regalite S1100 (Eastman Chemical Company), 29.5 wt % cycloaliphatic HC resin Polybut 10 (Productos Uhpon), polyisobutylene 12.0 wt % Polybut 30 (Productos Uhpon), polyisobutylene  3.0 wt % Irganox 1010 (BASF SE), antioxidant 0.35 wt % Irganox PS 802 FL (BASF SE), antioxidant 0.15 wt %

(11) This adhesive had a viscosity of about 11,300 mPas at 160° C. (Brookfield RVT spindle 21) and a softening point of 87.8/87.9° C. (ASTM E 28). With a 50 μm PET coating in a quantity of 40 g/m.sup.2 with a heating table/heating blade at 150° C. adhesive temperature, the adhesive exhibited an adhesive bond on steel and PE after 20 minutes of 31 and 15 N/25 mm, respectively, and of 33 and 32 N/25 mm on steel and glass, respectively, after 24 h. After regluing (130° C., 30 seconds, 5 kg/100 cm.sup.2), adhesive bonds on steel and PE and glass of 35 (70% adhesion failure) and 17 and 24 N/25 mm, respectively, were achieved after 24 h.

(12) TABLE-US-00004 Formulation 4: Poly-α-olefin (M.sub.n 5,000 g/mol; T.sub.g 96° C.; 15.0 wt % melt viscosity 2,500 mPas) Poly-α-olefin (M.sub.n 18,100 g/mol; T.sub.g 107° C.; 35.0 wt % melt viscosity 50,000 mPas) Regalite R1010 (Eastman Chemical Company),  5.0 wt % cycloaliphatic HC resin Regalite S1100 (Eastman Chemical Company), 29.6 wt % cycloaliphatic HC resin Polybut 10 (Productos Uhpon), polyisobutylene 12.0 wt % Polybut 30 (Productos Uhpon), polyisobutylene  3.0 wt % Irganox 1010 (BASF SE), antioxidant 0.35 wt % Irganox PS 802 FL (BASF SE), antioxidant 0.15 wt %

(13) This adhesive had a viscosity of about 7500 mPas at 160° C. (Brookfield RVT, spindle 21) and a softening point of 85.2/85.4° C. (ASTM E 28). With a 50 μm PET coating in a quantity of 40 g/m.sup.2 with a heating table/heating blade at 150° C. adhesive temperature, the adhesive exhibited an adhesive bond on steel and PE and glass after 20 minutes of 23 and 17 and 26 N/25 mm, respectively, and of 37 and 8 and 41 N/25 mm (50% adhesion failure) on steel and PE and glass, respectively, after 24 h. After regluing (130° C., 30 seconds, 5 kg/100 cm.sup.2), adhesive bonds on steel and PE and glass of 35 (80% adhesion failure) and 23 and 37 N/25 mm (80% cohesive failure), respectively, were achieved after 24 h.