Idemitsu Kosan Company, Limited

Masao Inoue

Yutaka Minami

Tomoaki Takebe

Kenji Kobayashi

Masami Kanamaru

Toyozo Fujioka

Kazuhiro Hashima

Provided is a hot-melt adhesive which satisfies both solidification rate and adhesiveness. A base polymer for a hot-melt adhesive which satisfies the following (1) and (2): (1) a modulus of elasticity in tension at 23&#xb0; C. is 400 MPa or less; and (2) a semi-crystallization time at 23&#xb0; C. is 20 minutes or less.

Base polymer for hot-melt adhesive agent, and hot-melt adhesive agent

A propylene-based polymer which satisfies the following (a1) to (d1): (a1) [mmmm]=60 to 80 mol %; (b1) weight-average molecular weight (Mw)=10,000 to 55,000; (c1) Mw/Mn&#x2266;2.5; and (d1) [rmrm]&#x2266;2.5 mol %.

Propylene-based polymer and hot melt adhesive

A 1-butene polymer satisfying the following (1), (2) and either (3) or (3'): a process for producing the polymer; a resin modifier comprising the polymer; and a hot-melt adhesive containing the polymer. (1) The intrinsic viscosity [&#x3b7;] as measured in tetralin solvent at 135&#xb0; C. is 0.01 to 0.5 dL/g. (2) The polymer is a crystalline resin having a melting point (Tm-D) of 0 to 100&#xb0; C., the melting point being defined as the top of the peak observed on the highest-temperature side in a melting endothermic curve obtained with a differential scanning calorimeter (DSC) in a test in which a sample is held in a nitrogen atmosphere at &#x2212;10&#xb0; C. for 5 min and then heated at a rate of 10&#xb0; C./min. (3) The stereoregularity index {(mmmm)/(mmrr+rmmr)} is 30 or lower. (3&#x2032;) The mesopentad content (mmmm) determined from a nuclear magnetic resonance (NMR) spectrum is 68 to 73%.

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Sodegaura, Japan

Masao Inoue