Adhesive composition for bonding a low-energy plastic surface to metal

Claim 2

An adhesive composition effective in bonding a low-energy plastic surface to metal which provides an improved tensile lap shear strength consisting essentially of: (1) about 20 to about 55 weight percent of an ethylene-vinyl ester copolymer having from about 9 to about 35 weight percent of a vinyl ester, said vinyl ester having 2 to 4 carbon atoms; (2) about 25 to about 40 weight percent of a tackifier selected from the group consisting of (a) a rosin, (b) a rosin ester, (c) a terpene resin, (d) a terpene-phenolic resin and (e) a rosin-modified phenolic resin; (3) about 0.25 to about 5 weight percent of a silane having a structural formula: R(CH.sub.2).sub.n [NH(CH.sub.2).sub.3 ].sub.m Six.sub.3 wherein R is selected from the group consisting of amino, mercapto, glycicoxylpropyl, epoxycyclohexyl, methacryloxy and vinyl; n is an integer from 0 to 6; m, when R is amino, is an integer from 0 to 1; m, when R is selected from the group consisting of mercapto, glycidoxylpropyl, epoxycyclohexyl, methacryloxy and vinyl is the integer 0; and X is selected from the group consisting of Cl, OCH 3 , OC 2 H 5 and OC 2 H 4 OCH 3 ; and (4) about 5 to about 54.75 weight percent of a wax.

Claim 3

An adhesive composition according to claim 1, wherein said ethylene-vinyl ester copolymer is selected from the group consisting of ethylene-vinyl acetate, ethylene-vinyl formate, ethylene-vinyl propionate, ethylene-vinyl butyrate and mixtures thereof.

Claim 4

An adhesive composition according to claim 1, wherein said copolymer contains from about 12 to about 25 weight percent of a vinyl ester.

Claim 5

An adhesive composition according to claim 1, wherein said copolymer has a melt index of about 0.5 to about 200 as measured by ASTM-1238-52T.

Claim 6

An adhesive composition according to claim 1, wherein said copolymer has a melt index of about 2.0 to about 100.

Claim 7

An adhesive composition according to claim 1, wherein said tackifier has a softening point of about 40 to about 150° C.

Claim 8

An adhesive composition according to claim 1, wherein said tackifier has a softening point of about 65 to about 135° C.

Claim 9

An adhesive composition according to claim 1, wherein said tackifier is a rosin.

Claim 10

An adhesive composition according to claim 8, wherein said rosin is a hydrogenated rosin.

Claim 11

An adhesive composition according to claim 1, wherein said tackifier is a rosin ester.

Claim 12

An adhesive composition according to claim 10, wherein said rosin ester is a glycerine ester of hydrogenated rosin.

Claim 13

An adhesive composition according to claim 1, wherein said tackifier is a terpene resin.

Claim 14

An adhesive composition according to claim 12, wherein said terpene resin is a polyterpene.

Claim 15

An adhesive composition according to claim 1, wherein said tackifier is a terpene-phenolic resin.

Claim 16

An adhesive composition according to claim 1, wherein said tackifier is a rosin-modified phenolic resin.

Claim 17

An adhesive composition according to claim 1, wherein R in said silane is amino.

Claim 18

An adhesive composition according to claim 1, wherein R in said silane is mercapto.

Claim 19

An adhesive composition according to claim 1, wherein R in said silane is glycidoxypropyl.

Claim 20

An adhesive composition according to claim 1, wherein R in said silane is epoxycyclohexyl.

Claim 21

An adhesive composition according to claim 1, wherein R in said silane is methacryloxy.

Claim 22

An adhesive composition according to claim 1, wherein R in said silane is vinyl.

Claim 23

An adhesive composition according to claim 1, wherein n in said silane is an integer from 0 to 3.

Claim 24

An adhesive composition according to claim 1, wherein X in said silane is Cl.

Claim 25

An adhesive composition according to claim 1, wherein X in said silane is OCH 3 .

Claim 26

An adhesive composition according to claim 1, wherein X in said silane is OC 2 H 5 .

Claim 27

An adhesive composition according to claim 1, wherein X in said silane is OC 2 H 4 OCH 3 .

Claim 28

An adhesive composition according to claim 1, wherein said silane is gamma-mercaptopropyltrimethoxysilane.

Claim 29

An adhesive composition according to claim 1, wherein said silane is beta-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane.

Claim 30

An adhesive composition according to claim 1, wherein said silane is gamma-aminopropyltriethoxysilane.

Claim 31

An adhesive composition according to claim 1, wherein said silane is N-beta-(aminoethyl)-gamma-aminopropyltrimethoxy silane.

Claim 32

An adhesive composition according to claim 1, wherein said wax is a microcrystalline wax.

Claim 33

An adhesive composition according to claim 1, wherein said wax is an intermediate wax.

Claim 34

An adhesive composition according to claim 1, wherein said wax is a polyethylene.

Claim 35

An adhesive composition according to claim 1, wherein said wax is atactic polypropylene.

Claim 36

An adhesive composition according to claim 1, wherein said ethylene-vinyl ester copolymer is about 25 to about 52 weight percent; said tackifier is about 25 to about 40 weight percent; said silane is about 1 to about 3 weight percent and said wax is about 5 to about 49 weight percent of the total composition.

Claim 37

A process for bonding a low-energy plastic surface having a critical surface tension of about 24 to about 37 dynes per centimeter to a metal surface which comprises: (A) heating said low-energy plastic surface that will be bonded to a temperature of at least about 50° C. and heating said metal surface to a temperature of at least about 130° C., (B) applying an adhesive composition effective in bonding a low-energy plastic surface to metal which provides an improved tensile lap shear strength, said adhesive composition consisting essentially of: (1) about 20 to about 55 weight percent of an ethylene-vinyl ester copolymer having from about 9 to about 35 weight percent of a vinyl ester, said vinyl ester having 2 to 4 carbon atoms; (2) about 25 to about 40 weight percent of a tackifier selected from the group consisting of at least one of (a) a rosin, (b) a rosin ester, (c) a terpene resin, (d) a terpene-phenolic resin and (e) a rosin-modified phenolic resin; (3) about 0.25 to about 5 weight percent of a silane having a structural formula: R(CH.sub.2).sub.n [NH(CH.sub.2).sub.3 ].sub.m SiX.sub.3 wherein R is selected from the group consisting of amino, mercapto, glycidoxylpropyl, epoxycyclohexyl, methacryloxy and vinyl; n is an integer from 0 to 6; m, when R is amino, is an integer from 0 to 1; m, when R is selected from the group consisting of mercapto, glycidoxypropyl, epoxycyclohexyl, methacryloxy and vinyl, is the integer 0; and X is selected from the group consisting of Cl, OCH 3 OC 2 H 5 and OC 2 H 4 OCH 3 and (4) about 5 to about 54.75 weight percent of a wax to at least one of said surfaces and wherein said adhesive composition is at a temperature within the range of about 140 to about 240° C. at the time of application and then (c) bringing said surfaces in contact with each other.

Claim 38

A process for bonding a low-energy plastic surface having a critical surface tension of about 24 to about 37 dynes per centimeter to a metal surface which comprises: (A) heating said low-energy plastic surface that will be bonded to a temperature of at least about 50° C. and heating said metal surface to a temperature of at least about 130° C., (B) applying an adhesive composition effective in bonding a low-energy plastic surface to metal which provides an improved tensile lap shear strength, said adhesive composition consisting essentially of: (1) about 20 to about 55 weight percent of an ethylene-vinyl ester copolymer having from about 9 to about 35 weight percent of a vinyl ester, said vinyl ester having 2 to 4 carbon atoms; (2) about 25 to about 40 weight percent of a tackifier selected from the group consisting of at least one of (a) a rosin, (b) a rosin ester, (c) a terpene resin, (d) a terpene-phenolic resin and (e) a rosin-modified phenolic resin; (3) about 0.25 to about 5 weight percent of a silane having a structural formula: R(CH.sub.2).sub.n [NH(CH.sub.2).sub.3 ].sub.m SiX.sub.3 wherein R is selected from the group consisting of amino, mercapto, glycidoxylpropyl, epoxycyclohexyl, methacryloxy and vinyl; n is an integer from 0 to 6; m, when R is amino, is an integer from 0 to 1; m, when R is selected from the group consisting of mercapto, glycidoxypropyl, epoxycyclohexyl, methacryloxy and vinyl, is the integer 0; and X is selected from the group consisting of Cl, OCH 3 OC 2 H 5 and OC 2 H 4 OCH 3 and (4) about 5 to about 54.75 weight percent of a wax to at least one of said surfaces and wherein said adhesive composition is at a temperature within the range of about 140 to about 240° C. at the time of application and then (c) bringing said surfaces in contact with each other.

Claim 39

A process according to claim 36 wherein said heating of said low-energy plastic surface is to a temperature of about 60 to about 130° C.; said heating of said metal surface is to a temperature of about 130 to about 170° C.; and wherein said adhesive composition is at a temperature within the range of about 160 to about 220° C.

Claim 40

A process according to claim 36 wherein said low-energy plastic surface is polyethylene.

Claim 41

A process according to claim 36 wherein said low-energy plastic surface is polypropylene.