Polypropylene-based adhesive and method for producing same

Patent metadata

Field	Value
Publication number	US-12110424-B2
Application number	US-201917264619-A
Country	US
Kind code	B2
Filing date	Jul 31, 2019
Priority date	Aug 2, 2018
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

A polypropylene-based adhesive containing a polypropylene-based resin (A′) prepared by reducing the weight-average molecular weight of a polypropylene-based resin (A) by decomposition, in which the melting endotherm (ΔH-D) of the polypropylene-based resin (A) is 0 J/g or more and 80 J/g or less, as obtained from a melting endothermic curve drawn by holding a sample at −10° C. for 5 minutes in a nitrogen atmosphere followed by heating it at 10° C./min using a differential scanning calorimeter (DSC).

First claim

The invention claimed is:

1. A polypropylene-based adhesive, comprising:
a polypropylene-based resin (A′) prepared by reducing a weight-average molecular weight of a polypropylene-based resin (A) by decomposition, in which a melting endotherm (ΔH-D) of the polypropylene-based resin (A) is 5 J/g or more and 80 J/g or less, as obtained from a melting endothermic curve drawn by holding a sample at −10° C. for 5 minutes in a nitrogen atmosphere followed by heating the sample at 10° C./min using a differential scanning calorimeter (DSC),
wherein
the polypropylene-based resin (A′) has a vinylidene group as a terminal unsaturated group contained per molecule of the polypropylene-based resin (A′) of 0.9 or more and 2.0 or less,
the polypropylene-based resin (A) has a melting point (Tm-D) of 20° C. or higher and 120° C. or lower, and
the polypropylene-based adhesive comprises a radical generator (B) in an amount of 0.01 parts by mass or more and 5 parts by mass or less relative to 100 parts by mass of the polypropylene-based resin (A).

2. The polypropylene-based adhesive according to claim 1 , wherein the weight-average molecular weight (Mw) of the polypropylene-based resin (A) is 150,000 or less.

3. The polypropylene-based adhesive according to claim 1 , wherein the polypropylene-based resin (A) has a viscosity of 400,000 mPa·s or less, as measured with a B viscosity viscometer.

4. The polypropylene-based adhesive according to claim 1 , wherein the polypropylene-based resin (A) has a molecular weight distribution (Mw/Mn) of 4.0 or less.

5. The polypropylene-based adhesive according to claim 1 , wherein the polypropylene-based resin (A) is a propylene homopolymer.

6. The polypropylene-based adhesive according to claim 1 , further comprising:
a tackifier resin (C) in an amount of 0 part by mass or more and 400 parts by mass or less relative to 100 parts by mass of the polypropylene-based resin (A).

7. The polypropylene-based adhesive according to claim 1 , further comprising:
an oil (D) in an amount of 0 part by mass or more and 100 parts by mass or less relative to 100 parts by mass of the polypropylene-based resin (A).

8. The polypropylene-based adhesive according to claim 1 , further comprising:
a wax (E) in an amount of 0 part by mass or more and 50 parts by mass or less relative to 100 parts by mass of the polypropylene-based resin (A).

9. A laminate, comprising:
the polypropylene-based adhesive of claim 1 .

10. A nonwoven fabric, comprising:
the polypropylene-based adhesive of claim 1 .

11. A method for producing a polypropylene-based adhesive, the method comprising: reducing a weight-average molecular weight of a polypropylene-based resin (A); and
decomposing the polypropylene-based resin (A) in the presence of a radical generator (B), thereby producing a polypropylene-based resin (A′),
wherein
a melting endotherm (ΔHm-D) of the polypropylene-based resin (A) is 5 Jig or more and 80 J/g or less, as obtained from a melting endothermic curve drawn by holding a sample at −10° C. for 5 minutes in a nitrogen atmosphere followed by heating the sample at 10° C./min using a differential scanning calorimeter (DSC),
the polypropylene-based resin (A) has a melting point (Tm-D) of 20° C. or higher and 120° C. or lower,
the polypropylene-based adhesive comprises a radical generator (B) in an amount of 0.01 parts by mass or more and 5 parts by mass or less relative to 100 parts by mass of the polypropylene-based resin (A), and
the polpropylene-based resin (A′) has a vinylidene group as a terminal unsaturated group contained per molecule of the polypropylene-based resin (A′) of 0.9 or more and 2.0 or less.

12. The method according to claim 11 ,
wherein the reducing is carried out by at least one method selected from the group consisting of adding a radical generator (B), heating and irradiating with radiation.

Assignees

• Idemitsu Kosan Co

Inventors

• Fujii Nozomu
• Kanamaru Masami
• Okamoto Takuji

Classifications

• Y10T442/20

  Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer · CPC title

• C09J191/06

  Waxes · CPC title

• C08K5/14

  Peroxides · CPC title

• C08K5/01

  Hydrocarbons {(C08K5/0091 takes precedence)} · CPC title

• C09J2301/162

  the carrier being a laminate constituted by plastic layers only · CPC title