Thermally crosslinkable composition

Abstract

The present invention relates to a thermally crosslinkable composition comprising an acid-modified polymer A having a melting point of 110 to 150° C. and a crystallization temperature of 50 to 90° C., an acid-modified polymer B having a melting point of 30 to 110° C. and a crystallization temperature of lower than 50° C., a tackifier resin, and a curing agent, wherein the thermally crosslinkable composition has a crystallization temperature of 30 to 70° C.

Claims

1. A thermally crosslinkable composition comprising an acid-modified olefin-based polymer A containing 20 to 90% by mass of structural units derived from propylene, 1 to 60% by mass of structural units derived from 1-butene, and 0.1 to 10% by mass of structural units derived from ethylene and having a melting point of 110 to 150° C. and a crystallization temperature of 50 to 90° C., an acid-modified olefin-based polymer B containing 55% to 95% by mass of structural units derived from propylene and having a melting point of 30 to 110° C. and a crystallization temperature of lower than 50° C., a tackifier resin, and a curing agent, wherein the thermally crosslinkable composition has a crystallization temperature of 30 to 70° C.

2. The thermally crosslinkable composition according to claim 1 comprising 30 to 200 parts by mass of the acid-modified olefin-based polymer B based on 100 parts by mass of the acid-modified olefin-based polymer A, and 20 to 200 parts by mass of the tackifier resin and 0.2 to 3 parts by mass of the curing agent based on 100 parts by mass of a total amount of the acid-modified olefin-based polymers A and B.

3. The thermally crosslinkable composition according to claim 1, wherein a content of the tackifier resin having an acid value of 5 or less is 20 to 100% by mass based on 100% by mass of a whole tackifier resin.

4. The thermally crosslinkable composition according to claim 3, wherein the tackifier resin having an acid value of 5 or less is selected from the group consisting of rosin resins, terpene resins and petroleum resins.

5. The thermally crosslinkable composition according to claim 1, wherein the curing agent is a solid polyamine compound having a melting point of 150° C. or higher.

6. The thermally crosslinkable composition according to claim 5, wherein the solid polyamine compound having a melting point of 150° C. or higher is a hydrazide-based polyamine.

7. The thermally crosslinkable composition according to claim 1, further comprising an acid-unmodified thermoplastic resin.

8. The thermally crosslinkable composition according to claim 7, wherein the acid-unmodified thermoplastic resin is an acid-unmodified styrene-containing thermoplastic elastomer.

9. The thermally crosslinkable composition according to claim 1, further comprising a solvent.

10. A hot melt adhesive comprising the thermally crosslinkable composition according to claim 1.

11. A film adhesive comprising the thermally crosslinkable composition according to claim 1.

12. An adhesive for adherent surface material, wherein the adhesive comprises the thermally crosslinkable composition according to claim 1.

13. An adherent surface material comprising the adhesive according to claim 12.

14. An automotive interior component comprising the adherent surface material according to claim 13 and a polyolefin substrate.

15. An architectural interior material comprising the adherent surface material according to claim 13 and the polyolefin substrate.

Description

EXAMPLES

(1) [Melting Point]

(2) In relation to the melting point, a sample was heated to 200° C. at a rate of 10° C./min, and a peak top temperature at an endothermic peak observed by a differential scanning calorimeter (DSC) was defined as the melting point.

(3) [Crystallization Temperature]

(4) In relation to the crystallization temperature, a sample was heated to 200° C. and cooled at a rate of 10° C./min, and a peak top temperature at an exothermic peak observed by the differential scanning calorimeter (DSC) was defined as the crystallization temperature.

(5) [Acid Value]

(6) The acid value was determined in accordance with JIS K 0070.

(7) [Thermally Crosslinkable Composition]

(8) An acid-modified polymer, a tackifier resin, a curing agent, and a thermoplastic resin in parts shown in the following Table 1 were added to a solvent, and stirred and dispersed at 80° C. for 2 hours to obtain an adhesive.

(9) [Sample for Bonding Test]

(10) The adhesive was applied on a polyethylene foam surface material so as to have a post-drying thickness of 50 μm, and then dried at 60° C. for 5 minutes. Subsequently, within 1 day after application of the adhesive, the surface material was overlaid on a PP board which had been heated at 80° C. for 2 minutes while heating the surface material to 150° C. or higher using a far-infrared heater, and compressed at 0.5 kg/cm.sup.2 for 20 seconds to obtain a laminate (condition 1). Also, a laminate was obtained in the same manner as in condition 1 except for using a surface material which had been stored (storage temperature: 5 to 35° C.) for 6 months after application of the adhesive (condition 2).

(11) [Initial Creep]

(12) Immediately after obtaining the laminate, the laminate was loaded at 200 g/25 mm in 90° direction under an atmosphere at 60° C., and after 5 minutes, a peeling length (mm) was measured.

(13) [Initial Peel Strength]

(14) After 5 minutes of obtaining the laminate, a peel strength (N/25 mm) under 180° peeling was measured.

(15) [Heat Creep Resistance]

(16) After the laminate was left at rest at 20° C. for 24 hours, the laminate was loaded at 200 g/25 mm in 90° direction under an atmosphere at 90° C., and a peeling length (mm) after 24 hours was measured.

(17) TABLE-US-00001 TABLE 1 Examples Comparative Examples 1 2 3 4 5 6 7 8 1 2 3 4 5 Acid-modified polymer 1 100 120 80 140 80 100 160 60 — — 100 200 — Acid-modified polymer 2 100 80 120 60 120 100 40 140 — — 100 — 200 Acid-unmodified Polymer 1 — — — — — — — — — 100 — — — Acid-unmodified Polymer 2 — — — — — — — — — 100 — — — Acid-unmodified Polymer 3 — — — — — — — — 100 — — — — Acid-unmodified Polymer 4 — — — — — — — — 100 — — — — Tackifier resin 1 100 — — — — — — — — — — 100 — Tackifier resin 2 — 100 50 100 100 100 100 100 100 100 — 100 Tackifier resin 3 — — 50 100 — — — — — — — — — Curing agent 2 2 2 2 5 0.5 2 2 2 2 — 2 2 Thermoplastic resin 50 50 50 50 50 50 50 50 50 50 50 50 50 Solvent 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 Unit: g

(18) TABLE-US-00002 TABLE 2 Examples Comparative Examples 1 2 3 4 5 6 7 8 1 2 3 4 5 Composition Crystallization 52 58 45 60 45 60 64 43 — 58 50 80 29 temperature [° C.] Melting point 122 119 116 126 125 123 124 115 — 122 121 122 72 [° C.] Condition 1 Initial creep 5 0 0 5 0 0 7 0 Dropping Dropping 0 Dropping 10 [mm] BA BA BA out out out CF BA BA BA Initial peel 20 30 30 20 30 30 25 30 — — 30 — 20 strength FB/ FB FB FB/ FB FB FB/ FB FB CF [N/25 mm] BA BA BA Heat creep 5 0 5 5 0 3 0 8 Dropping Dropping Dropping Dropping Dropping resistance BA BA BA BA out out out out out [mm] BA BA CF BA CF Condition 2 Initial creep 10 0 5 5 0 0 9 0 — — 0 Dropping 10 [mm] BA BA BA BA out CF BA Initial peel 5 30 30 10 20 30 25 30 — — — — 20 strength FB/ FB FB FB/ BA FB FB/ FB CF [N/25 mm] BA BA BA Heat creep 5 0 0 15 5 3 0 9 — — Dropping Dropping Dropping resistance BA BA BA BA BA out out out [mm] CF BA CF BA: Interfacial failure on the substrate side FB: Material failure of the surface material CF: Cohesive failure of the adhesive
[Acid-Modified Polymer 1]

(19) Acid-modified PBE 120: maleic acid-modified propylene/1-butene/ethylene copolymer, melting point: 120° C., crystallization temperature: 80° C., weight average molecular weight: 75000, 1-butene content: about 17% by mass, acid content: 3% by mass

(20) [Acid-Modified Polymer 2]

(21) Acid-modified PB 70: maleic acid-modified propylene/1-butene copolymer, melting point: 70° C., crystallization temperature: 20° C., weight average molecular weight: 65000, 1-butene content: about 26% by mass, maleic acid content: 2% by mass

(22) [Acid-Unmodified Polymer 1]

(23) Acid-unmodified PBE 120: propylene/1-butene/ethylene copolymer, melting point: 120° C., crystallization temperature: 80° C., weight average molecular weight: 70000, 1-butene content: about 18% by mass, acid content: 0% by mass.

(24) [Acid-Unmodified Polymer 2]

(25) Acid-unmodified PB70: propylene/1-butene copolymer, melting point: 70° C., crystallization temperature: 25° C., weight average molecular weight: 68000, 1-butene content: about 26% by mass, maleic acid content: 0% by mass.

(26) [Acid-Unmodified Polymer 3]

(27) Vestoplast (registered trademark) 520, softening point: 87° C., 1-butene-rich amorphous poly-α-olefin, weight average molecular weight: 63000

(28) [Acid-Unmodified Polymer 4]

(29) Vestoplast (registered trademark) 750, softening point: 107° C., polypropylene-rich amorphous poly-α-olefin, weight average molecular weight: 92000

(30) [Tackifier Resin 1]

(31) Neopolymer 140: petroleum resin-based tackifier, softening point: 145° C., acid value: 0 mgOH/g, weight average molecular weight: 2100, functional group: none

(32) [Tackifier Resin 2]

(33) FK 100: disproportionated rosin type, acid value: 5 or less, softening point: 96 to 102° C.

(34) [Tackifier Resin 3]

(35) Haritack 4821: rosin-modified maleic acid, acid value: 15 to 30, softening point: 100 to 115° C.

(36) [Curing agent]

(37) Hydrazide dodecanedioate (DDH), melting point: 190° C.

(38) [Thermoplastic Resin]

(39) Tufprene A, manufactured by Asahi Kasei Corporation, acid-unmodified styrene-containing thermoplastic elastomer (styrene content: about 40%, butadiene content: about 60%)