Hot melt adhesive

Abstract

An object of the present invention is to provide a hot melt adhesive being environmentally-friendly, having excellent adhesion property to various substrates such as paper substrate and polyolefin substrate, as well having excellent thermal stability. The present invention relates to a hot melt adhesive comprising: (A) a polar functional group-modified polymer, (B) an aliphatic polyester-based resin, (C) an olefin-based polymer, and (D) a tackifier resin.

Claims

1. A hot melt adhesive comprising: (A) a polar functional group-modified polymer, (B) an aliphatic polyester-based resin, (C) an olefin-based polymer that is a solid at room temperature, and (D) a tackifier resin.

2. The hot melt adhesive according to claim 1, wherein the polar functional group is at least one functional group selected from the group consisting of an acid anhydride group, a maleic acid group, a carboxyl group, an amino group, an imino group, an alkoxysilyl group, a silanol group, a silyl ether group, a hydroxyl group and an epoxy group.

3. The hot melt adhesive according to claim 2, wherein the polar functional group is at least one functional group selected from a maleic acid group or an amino group.

4. The hot melt adhesive according to claim 1, wherein the aliphatic polyester-based resin (B) comprises at least one selected from a polylactic acid-based resin and poly(butylene succinate).

5. The hot melt adhesive according to claim 1, comprising 5 to 60 parts by weight of component (C) to 100 parts by weight of total weight of components (A) to (D).

6. The hot melt adhesive according to claim 1 comprising: (A) an amino group group-modified SEBS polymer, (B) a polylactic acid resin, (C) an ethylene copolymer having propylene, butene or octene comonomers, and (D) a tackifier resin.

7. An article comprising the adhesive of claim 1.

8. The article of claim 7 which is a vehicle interior.

9. A hot melt adhesive comprising: (A) a polar functional group-modified olefin-based polymer that is an ethylene or α-olefin copolymer having 3 to 20 carbon atoms; (B) an aliphatic polyester-based resin, (C) an olefin-based polymer, and (D) a tackifier resin.

Description

EXAMPLES

(1) For the purpose of describing the present invention in more details and more specifically, the present invention will be described below using Examples. These Examples are for describing the present invention, and do not limit the present invention in any way.

(2) Components blended in hot melt adhesives in Examples and Comparative Examples are shown below.

(3) <(A) Polar Functional Group-Modified Polymers>

(4) (A1) Polar functional group-modified conjugated diene-based copolymers

(5) (A1-1) amino group-modified SEBS (“DYNARON 8630P” manufactured by JSR)

(6) (A1-2) maleic acid group-modified SEBS (“Tuftec M1913” manufactured by Asahi Kasei Chemicals Corporation)

(7) (A2) Polar functional group-modified polyolefin-based polymers

(8) (A2-1) Ethylene/methyl acrylate/glycidyl methacrylate copolymerized resin (“BONDFAST 7M” (trade name) manufactured by Sumitomo Chemical Co., Ltd.)

(9) <(B) Aliphatic Polyester-Based Resins>

(10) (B1) Poly LD-lactic acid resin (“4060D” (trade name) manufactured by NatureWorks LLC)

(11) (B2) Poly(butylene succinate) resin (“AD92W” (trade name) manufactured by Mitsubishi Chemical Corporation)

(12) <(C) Olefin-Based Polymer>

(13) (C1) Propylene/ethylene/1-butene copolymer (“VESTO PLAST 708” manufactured by Evonik Degussa Co., Ltd.)

(14) (C2) Ethylene/octene copolymer (“AFFINITY GA1950” manufactured by Dow Chemical Company)

(15) (C3) Ethylene/vinyl acetate copolymer (“ULTRASEN 722” manufactured by Tosoh Corporation)

(16) (C4) Polyethylene (“PETROSEN 249” manufactured by Tosoh Corporation)

(17) (C5) Polypropylene (“PM940M” manufactured by SunAllomer Ltd.)

(18) <(D) Tackifier Resins>

(19) (D1) a hydrogenated aromatic petroleum resin (“I-marv P100” (trade name) manufactured by Idemitsu Kosan Co., Ltd.)

(20) (D2) C5-based petroleum resin (“EAST TACK H-100W” manufactured by Eastman Chemical Company)

(21) (D3) Hydrogenated terpene-based resin (“CLEARON M105,” made by Yasuhara Chemical Co., Ltd.)

(22) <(E) Antioxidants>

(23) (E1) Antioxidant (AO-60 manufactured by ADEKA CORPORATION)

(24) These components (A) to (E) were blended in blending proportions shown in Table 1 to Table 3, and melted and mixed at about 160° C. over about 3 hours using a universal stirrer to produce the hot melt adhesives of Examples 1 to 8 and Comparative Examples 1 to 5. The numerical values regarding the composition (blend) of the hot melt adhesives shown in Tables 1 to 3 are all parts by weight.

(25) Each of the hot melt adhesives in Examples and Comparative Examples was evaluated for the thermal stability, the peel strength to various substrates, and the shear strength. The summary of each of the evaluation is described in the following.

(26) <Shear Adhesion Strength (PET/PET and PP/PP)>

(27) The adhesion property of a hot melt adhesive was evaluated from the tensile shear strength to an adherend of PET or polypropylene (PP). Each of the adherend for use had a strip shape with a width of 25 mm, a length of 100 mm, and a thickness of 2 mm. The hot melt adhesive was melted in air at 180° C. Two of the adherends were laminated so as to form a sample piece having an application area of 25 mm square with a thickness of 2 mm.

(28) The tensile shear strength of the sample piece left intact for 1 day in a room at 23° C. was measured with a UR-500L load cell (maximum load: 500 kg) made by Orientec Co., Ltd., and an RTM-250 testing machine made by Orientec Co., Ltd., at a stroke velocity of 300 mm/min. The evaluation criteria are as follows.

(29) ∘∘: more than 1.0 MPa

(30) ∘: 0.5 MPa or more and 1.0 MPa or less

(31) Δ: 0.2 MPa or more and less than 0.5 MPa

(32) x: less than 0.2 MPa, or unmeasurable due to no formation of hot melt

(33) <180° Peel Strength: PP Plate/Polyester Nonwoven Fabric>

(34) The adhesion property of a hot melt adhesive was evaluated from the peel strength to an adherend of PP plate/polyester nonwoven fabric. The hot melt adhesive was melted in air at 180° C. and applied to a PP substrate with an amount applied of 0.30 g/inch, which was then attached to a polyester nonwoven fabric so as to form a sample piece.

(35) The 180° peel strength of the sample piece left intact for 1 day in a room at 23° C. was measured with a UR-500L load cell (maximum load: 500 kg) made by Orientec Co., Ltd., and an RTM-250 testing machine made by Orientec Co., Ltd., at a stroke velocity of 300 mm/min. The evaluation criteria are as follows.

(36) ∘∘: more than 10 kg/inch

(37) ∘: more than 5 kg/inch and 10 kg/inch or less

(38) Δ: more than 0 kg/inch and 5 kg/inch or less

(39) x: 0 kg/inch or unmeasurable due to no formation of hot melt

(40) <Adhesion: Paper/Paper>

(41) The adhesion property of a hot melt adhesive was evaluated from the peel strength to adherend of paper (K liner corrugated cardboard). A hot melt adhesive melted at 180° C. in the air was applied to the paper substrate with an application amount of 0.15 g/inch and the paper substrates were laminated to produce a sample piece.

(42) The 90° peel strength of the sample piece left intact for 1 day in a room at 23° C. was measured with a UR-500L load cell (maximum load: 500 kg) made by Orientec Co., Ltd., and an RTM-250 testing machine made by Orientec Co., Ltd., at a stroke velocity of 300 mm/min. The evaluation criteria are as follows. “Material breakage” means that the sample piece is broken, and “interface breakage” means that the sample piece is detached from the interface with the adhesive layer without breakage.

(43) ∘∘: Peel strength was more than 1.0 kg/inch and material breakage occurred.

(44) ∘: Peel strength was more than 1.0 kg/inch and interface breakage occurred.

(45) Δ: Peel strength was 0.5 kg/inch or more and less than 1.0 kg/inch and interface breakage occurred.

(46) x: Peel strength was less than 0.5 kg/inch and interface breakage occurred, or peel strength was unmeasurable due to no formation of hot melt adhesive.

(47) <Thermal Stability>

(48) The thermal stability was visually determined by a change in appearance after 35 g of the hot melt adhesive was placed in a 70 mL glass bottle and allowed to stand in a dryer oven at 150° C. for 24 hours.

(49) ∘∘: Phase separation, carbonized product or ring (a degraded product of the hot melt adhesive deposited in a ring shape) was not observed.

(50) ∘: Phase separation, carbonized product and a ring were very slightly observed.

(51) Δ: Phase separation, carbonized product and a ring were slightly observed.

(52) x: Phase separation, carbonized product and a ring were observed.

(53) TABLE-US-00001 TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 (A1-1) 5 5 (A1-2) 10 (A2-1) 2 (B1) 25 25 25 (B2) 35 (C1) 30 20 (C2) 25 33 (C3) (C4) (C5) (D1) 40 40 40 (D2) 40 (D3) (E1) 0.5 0.5 0.5 0.5 total (parts by weight) 100.5 100.5 100.5 100.5 Shear adhesion strength PP/PP (MPa) >1.0 >1.0 >1.0 >1.0 Evaluation ∘∘ ∘∘ ∘∘ ∘∘ Shear adhesion strength PET/PET (MPa) >1.0 >1.0 >1.0 >1.0 Evaluation ∘∘ ∘∘ ∘∘ ∘∘ 180° Peel strength PP/polyester nonwoven fabric (kg/inch) >10 >10 >10 >10 Evaluation ∘∘ ∘∘ ∘∘ ∘∘ Peel strength paper/paper (kg/inch) 1.2 1.3 1.2 1.3 material material material material breakage breakage breakage breakage Evaluation ∘∘ ∘∘ ∘∘ ∘∘ Thermal stability ∘∘ ∘ ∘ ∘∘ 150° C. × 1 day Ex. = Example

(54) TABLE-US-00002 TABLE 2 Ex. 5 Ex. 6 Ex. 7 Ex. 8 (A1-1) 5 5 5 5 (A1-2) (A2-1) (B1) 25 25 10 10 (B2) (C1) 40 (C2) 30 45 (C3) 30 (C4) 5 (C5) 5 (D1) 40 40 (D2) (D3) 35 40 (E1) 0.5 0.5 0.5 0.5 Total (parts by weight) 100.5 100.5 100.5 100.5 Shear adhesion strength PP/PP (MPa) >1.0 >1.0 >1.0 >1.0 Evaluation ∘∘ ∘∘ ∘∘ ∘∘ Shear adhesion strength PET/PET (MPa) >1.0 >1.0 >1.0 >1.0 Evaluation ∘∘ ∘∘ ∘∘ ∘∘ 180° Peel strength PP/polyester nonwoven fabric (kg/inch) >10 >10 >10 >10 Evaluation ∘∘ ∘∘ ∘∘ ∘∘ Peel strength paper/paper (kg/inch) 1.3 1.1 1.4 1.4 material material material material breakage breakage breakage breakage Evaluation ∘∘ ∘∘ ∘∘ ∘∘ Thermal stability ∘∘ ∘∘ ∘∘ ∘∘ 150° C. × 1 day Ex. = Example

(55) TABLE-US-00003 TABLE 3 Com- Com- Com- Com- Com- Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 (A1-1) 5 5 5 (A1-2) (A2-1) (B1) 30 30 25 25 (B2) (C1) 30 (C2) 30 (C3) (C4) (C5) 50 70 (D1) 40 40 45 70 (D2) (D3) (E1) 0.2 0.2 0.2 0.2 0.2 Total (parts by weight) 100.2 100.2 100.2 100.2 100.2 Shear adhesion strength PP/PP (MPa) N N 0.0 0.1 0.0 Evaluation x x x x x Shear adhesion strength PET/PET (MPa) N N 0.0 0.1 0.1 Evaluation x x x x x 180° Peel strength PP/polyester nonwoven fabric (kg/inch) N N 5.0 0.0 0.0 Evaluation x x Δ x x Peel strength paper/paper (kg/inch) N N 0.7 0.3 0.2 interface interface interface breakage breakage breakage Evaluation x x Δ x x Thermal stability x x ∘ ∘∘ ∘∘ 150° C. × 1 day Com-Ex. = Comparative Example N = impossible to measure

(56) As shown in Table 1 and Table 2, the hot melt adhesives in Examples 1 to 8 comprise all of the four components, i.e. the component A, the component B, the component C, and the component D, so that adhesion property is excellent not only to a paper substrate but also to a polyolefin substrate. Furthermore, the hot melt adhesives in Examples 1 to 8 include the components having excellent compatibility with each other, resulting in excellent thermal stability. The hot melt adhesives are environmentally preferred due to the inclusion of the component B.

(57) The hot melt adhesives in Comparative Examples 1 to 5 lack any one of the component A, the component B, the component C, and the component D (Table 3). Since the hot melt adhesives in Comparative Examples 1 and 2 do not comprise component A, the compatibility among the component B, the component C, and the component D is poor, resulting in poor thermal stability. Due to the poor compatibility among the respective components, the adhesion property of the hot melt adhesives in Comparative Examples 1 and 2 is below the level for evaluation. The hot melt adhesive in Comparative Example 3 does not comprise component B, and thus has poor adhesion property to a substrate, with extremely low shear strength, in particular. The hot melt adhesive in Comparative Example 4 does not comprise component D, and thus is merely a polymer composition, not a hot melt adhesive, and has poor adhesion property on the whole. The hot melt adhesive in Comparative Example 5 does not comprise component C, and thus has poorer adhesion property to a polyolefin substrate compared to the hot melt adhesives in Examples.

INDUSTRIAL APPLICABILITY

(58) The present invention can provide a hot melt adhesive, and a vehicle interior material coated with the hot melt adhesive. The vehicle interior material of the present invention manufactured from a polyolefin substrate is particularly effective.