HK1050911B - Low activation temperature adhesive composition with high peel strength and cohesive failure - Google Patents

Description

Adhesive composition with high peel strength and low activation temperature for cohesive failure

Field of the invention

The present invention relates to novel resin and adhesive compositions, and in particular to low activation temperature adhesive compositions that can be used as self-supporting films or can be co-extruded or extrusion coated on a substrate.

Background of the invention

Although acid-modified or acid anhydride-modified polymers are known to be useful as adhesives for bonding both metals and polyolefins, there is a need for adhesives that not only have high bond strength to both metals and polyolefins, but also need to be activatable at lower temperatures. Modified polyolefins, both traditional and currently commercially available, either sacrifice adhesion strength to metal or to polyolefin, or do not activate at low temperatures when bonded to metal or polyolefin. Furthermore, adhesive compositions that activate at low temperatures are generally very soft and tacky materials, making it difficult to handle these compositions in the form of free films (free film) in a hot lamination process, and handling these compositions may require very expensive release films (release film) to prevent blocking. And most current adhesives tend to lose significant bond strength over time after delivery. This phenomenon is known in the industry as "aging".

There are numerous patents in the art disclosing adhesive compositions, but these prior art patents are not satisfactory in all respects referred to in this specification. Examples of these prior art patents include U.S. patents 5516583, 4861676, 4861677, 4552819, and 5965255.

An example of the prior art is U.S. patent 5225842 issued to Zhongchuan (Nakagawa) 6.6.1993 which discloses an adhesive composition comprising an ethylene-vinyl acetate copolymer, a styrenic polymer resin, a graft-modified polyethylene, a polystyrene elastomer, and an ethylene-alpha-olefin copolymer. There is no disclosure of high impact polystyrene as a styrene resin used in combination with an ethylene/non-ethylene copolymer.

It has been found that the adhesive composition formulations of the present invention solve many, or all, of these problems. The adhesive composition of the present invention bonds both metals and polyolefins, is activated at lower temperatures and is easily handled as a free or coextruded film without requiring an intermediate layer or release paper. In addition, it has been found that these adhesive compositions produce 100% cohesive failure during peel testing. Cohesive failure is a desirable property because it is an indicator of high adhesive strength, which is so high that the adhesive strength is greater than the cohesive strength of the adhesive. Cohesive failure also allows for a convenient visual test to ensure that the multilayer structure is properly bonded when other testing methods are not readily available. Finally, there is a strong correlation between the cohesive failure mode of the adhesive and the retention properties of the adhesive strength after the product is delivered for use.

Accordingly, the present invention provides adhesive compositions that have excellent adhesion to metal substrates and to many polymeric materials, resulting in adhesive layers with high peel strength. The invention also allows the use of relatively low activation temperatures in the manufacture of profiled sheets.

The adhesive composition of the present invention may be used in the form of pellets as an adhesive resin or as an adhesive film.

Summary of The Invention

Accordingly, in one aspect, the present invention provides an adhesive composition made by mixing starting materials comprising:

(a)0 to 90 parts by weight of a polyolefin;

(b)5-95 parts by weight of a functional polyolefin;

(c)5-40 parts by weight of a polystyrene-based material; and

(d)0 to 30 parts by weight of an elastomer,

wherein the total amount of the components (a), (b), (c) and (d) in the resin composition is 100 parts by weight.

In a second aspect the present invention provides an adhesive composition made by mixing starting materials comprising:

(a)0 to 90 parts by weight of a non-olefin copolymer;

(b)5-95 parts by weight of a functional polyolefin;

(c)5-40 parts by weight of high impact polystyrene; and

(d)0 to 30 parts by weight of an elastomer,

wherein the total amount of the components (a), (b), (c) and (d) in the resin composition is 100 parts by weight.

Brief description of the drawings

Preferred embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals refer to like parts throughout the various views, and wherein:

fig. 1a and 1b are schematic illustrations of a five-layer laminate structure made using one embodiment of the adhesive composition of the invention.

Detailed description of the preferred embodiments

The invention will be described with reference to preferred embodiments.

The preferred resin and adhesive compositions of the invention described herein are melt blends of a number of polymers. These adhesives may be used in a variety of applications and have a variety of different properties depending on the particular application. One application of these preferred adhesives is in the construction industry for the manufacture of metal sheets in the form of composite structures comprising a metal matrix such as aluminum or steel bonded to a polyolefin core such as polyethylene. Preferred adhesive compositions of the invention are used to bond metal substrates to polyethylene cores.

In this application, it is important that the adhesive layer provide good adhesion of the polyolefin to the metal substrate. Also, cohesive failure of the adhesive during application is desirable and the adhesive should be relatively easy to formulate and use. It has been found that the adhesive compositions of the present invention provide excellent adhesion to metal substrates, to many polymeric materials. They produced 100% cohesive failure during the peel test. These adhesive compositions are useful as self-supporting films, making them easy to handle and process.

Preferred adhesive compositions of the invention are activated at lower temperatures than are typically used in the manufacture of building panels. For the preferred adhesive compositions, the activation temperature can be reduced to about 125 ℃, which reduced activation temperature results in considerable cost savings and safer handling for the manufacture of the board, since the use of a finish protective layer (which is required at higher temperatures to prevent mottling on the paint) can be eliminated from the manufacturing process.

In one aspect, the resin composition of the present invention comprises:

(a)0 to 90 parts by weight of a polyolefin;

(b)5-95 parts by weight of a functional polyolefin;

(c)5-40 parts by weight of a polystyrene-based material; and

(d)0 to 30 parts by weight of an elastomer,

wherein the total amount of the components (a), (b), (c) and (d) in the resin composition is 100 parts by weight.

In a second aspect, the resin composition of the present invention comprises:

(a)0 to 90 parts by weight of a non-olefin copolymer;

(b)5-95 parts by weight of a functional polyolefin;

(c)5-40 parts by weight of high impact polystyrene; and

(d)0 to 30 parts by weight of an elastomer,

wherein the total amount of the components (a), (b), (c) and (d) in the resin composition is 100 parts by weight.

In this patent specification, the term "polyolefin" refers to homopolymers of olefins and to copolymers thereof. More specifically, homopolymers include polymers composed of a single unsaturated olefin, such as polyethylene, polypropylene, polybutylene, or the like where the olefin contains from 2 to 20 carbon atoms. Copolymers of olefins include polymers composed of one or more unsaturated or polyunsaturated hydrocarbons having from 2 to 20 carbon atoms. Examples thereof include, but are not limited to, ethylene/propylene copolymers, ethylene/butene copolymers, ethylene/hexene copolymers, ethylene/octene copolymers, ethylene/styrene copolymers, ethylene/butene/octene copolymers, ethylene/propylene/norbornadiene copolymers, and propylene/butene copolymers.

In this patent specification, the term "non-olefin copolymer" refers to a copolymer of an olefin and a non-olefin. Non-olefins that may be copolymerized with olefins-primarily ethylene-include, but are not limited to, vinyl acetate, acrylates or methacrylates having 1-20 carbon atoms, unsaturated anhydrides such as maleic anhydride or itaconic anhydride, unsaturated acids such as maleic acid, fumaric acid, acrylic acid, methacrylic acid, or itaconic acid. Examples of copolymers of olefins and non-olefins include, but are not limited to, ethylene/vinyl acetate, ethylene/methyl acrylate, ethylene/butyl acrylate. These polymers can be made by methods well known in the art, including the use of metallocene catalysts, Ziegler-Natta catalysts, and other catalysts used in "low pressure" polymerization processes. Alternatively, these polymers can also be made under "high pressure" polymerization processes using, for example, free radical initiators. Mixtures or blends of polyolefins may be used.

In the patent specification, the term "functional polyolefin" refers to a polyolefin or non-olefin copolymer having specific functional groups that can react to form covalent bonds or ionic bonds. The functional polyolefins include grafted polyolefins as defined below.

The term "grafted polyolefin" means a polyolefin, a non-olefin copolymer or a mixture or blend of polyolefins and/or non-olefin copolymers onto which is grafted at least one monomer selected from ethylenically unsaturated carboxylic acids and ethylenically unsaturated carboxylic acid anhydrides, also not preferably including derivatives of these acids, and mixtures thereof. These acids and anhydrides may be monocarboxylic acids, dicarboxylic acids or polycarboxylic acids, examples being acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, itaconic anhydride, maleic anhydride and substituted maleic anhydrides, such as dimethylmaleic anhydride or crotonic anhydride (citronicic anhydride), nadic anhydride, nadic methyl anhydride and tetrahydrophthalic anhydride, with maleic anhydride being particularly preferred. Examples of derivatives of unsaturated acids are salts, amides, imides and esters thereof, such as monosodium and disodium maleate, acrylamide, glycidyl methacrylate and dimethyl fumarate. Grafted polyolefins are well known in the art and can be prepared by a variety of different methods, including hot grafting in an extruder or other mixing device, grafting in solution, or grafting in a fluidized bed reactor. Mixtures or blends of grafted polyolefins may also be used.

In the patent specification, the term "polystyrene" refers to homopolymers of styrene or alpha-methylstyrene, or copolymers of styrene and an unsaturated monomer such as, but not limited to, ethylene, butylene, butadiene or isoprene. Specific examples include, but are not limited to, ethylene/styrene random or block copolymers, ethylene/butadiene random or block copolymers, and hydrogenated and partially hydrogenated butadiene/styrene copolymers. Polystyrene based materials that are further modified to increase impact properties, such polystyrene based materials are commonly referred to as high impact polystyrene or HIPS, are also useful. Blends and mixtures of polystyrene systems may also be used. Specific examples include, but are not limited to, the High performance styrenics sold by Nova Chemicals (High Performance styrenics) and the name Index sold by Dow Chemicii^TMEthylene/styrene copolymers of (a).

In the patent specification, the term "elastomer" also refers to polyolefins or polystyrene based materials, but differs from the aforementioned polyolefins or polystyrene based materials in that its crystallinity is relatively low, that is, relatively amorphous. Elastomers as defined herein have hot melt properties-as measured by Differential Scanning Calorimetry (DSC) at 10 ℃/minute, a heating rate of less than 30 joules/g. Polyolefin Elastomers, for example, may be ethylene and α -olefin copolymers, including the low density metallocene ethylene/butene copolymers sold by ExxonMobil under the name "Extravt ®" or the metallocene ethylene/octene copolymers sold by DuPont Dow Elastomers under the name "Engage ®", also including the ethylene/propylene copolymers sold by ExxonMobil under the name "Vistalon ®", the ethylene/α -olefin copolymers sold by Mitsui under the name "Tafmer ®" or the ethylene/propylene/norbornadiene copolymers sold by DuPont Dow Elastomers under the name "Nordel ®", also including polybutene rubbers, polyisobutylenes. Examples of polystyrene-based elastomers include, but are not limited to, for example, diblock and triblock copolymers sold by Shell under the name "Kraton ®" or those sold by Firestone under the name "Stereon ®".

In addition to the components described above, the preferred adhesive compositions of the invention may contain minor amounts of other materials commonly used and well known in the adhesive art. These materials include, for example, primary and secondary (primary and secondary) antioxidants, stabilizers, slip additives, antiblock additives-such as silica or talc, dyes, pigments, and tackifying resins-such as in Kirk OthmerThose disclosed in Encyclopedia of Chemical TechnologyProvided that the addition of these additives does not significantly adversely affect the adhesive properties of the composition.

As is well known in the art, the binder composition of the present invention may be dry blended, subsequently melt mixed in a twin screw extruder and re-pelletized. These molten mixed resins can then be converted and applied by various techniques and processes. The adhesive can be converted into a film, for example, by cast or blown film die extrusion techniques, and the adhesive film can be laminated to a suitable substrate (e.g., metal or polyolefin). Alternatively, the adhesive composition can be coextruded with other polyolefins as skin layers on one or both surfaces of the polyolefin to produce a more economical adhesive film.

In addition, the incorporation of polar carrier resins, such as polyamides, ethylene vinyl alcohol copolymers (EVOH) or polyesters, with direct bonding to polar carrier materials using the adhesive compositions of the invention, results in coextruded films. These adhesive films can be laminated to various substrates by heat activating the adhesive film. Thermal activation can be carried out by a variety of methods including, but not limited to, direct contact with a hot plate or roller, absorption of infrared energy, direct heating in an oven or activation by RF frequency or microwave radiation.

In another application of the adhesive composition of the invention, the adhesive may be coated directly onto the substrate in a process well known in the art including, for example, extrusion lamination, extrusion coating, co-extrusion lamination, co-extrusion coating. The adhesive compositions of the invention may be used to bond polar carrier resins such as EVOH, polyamide or polyester. It can also be used to bond metals such as steel, aluminum, copper and brass and to bond polyolefins such as polyethylene, ethylene copolymers and polypropylene.

In a preferred embodiment of the present invention, there is provided a resin composition made from starting materials comprising:

(a)0 to 90 parts by weight, more preferably 20 to 60 parts by weight, of a linear low density polyethylene (e.g. commercially available from ExxonMobil under the name Extract ® or Nova Chemicals under the name Sclair ®);

(b) from 5 to 95 parts by weight, more preferably from 10 to 30 parts by weight, of a maleic anhydride grafted polyethylene (e.g., commercially available from DuPont under the designation Fusabond ®);

(c)5 to 40 parts by weight, more preferably 10 to 35 parts by weight, of high impact polystyrene (e.g., commercially available from Nova Chemicals under the name high performance styrene); and

(d)0 to 30 parts by weight, more preferably 10 to 25 parts by weight, of an ethylene-propylene diene rubber compound (e.g., commercially available from DuPont-Dow Elastomers under the designation NordelIP ®);

wherein the total amount of the components (a), (b), (c) and (d) in the resin composition is 100 parts by weight.

A second embodiment of the present invention provides an adhesive composition comprising:

(a) from 0 to 90 parts by weight, more preferably from 40 to 60 parts by weight, of an ethylene-vinyl acetate copolymer, preferably having from 3 to 40% by weight vinyl acetate, more preferably from 5 to 30% by weight vinyl acetate (for example, the ethylene-vinyl acetate copolymer sold by DuPont under the name Elvax ® is a suitable commercially available copolymer);

(b)5 to 95 parts by weight, more preferably 10 to 30 parts by weight, of a maleic anhydride grafted polyethylene (e.g., commercially available from DuPont under the name Fusabond ®);

(c)5 to 40 parts by weight, more preferably 10 to 35 parts by weight, of high impact polystyrene (e.g., commercially available from Nova Chemicals under the designation high performance styrene); and

(d) from 0 to 30 parts by weight, more preferably from 10 to 25 parts by weight, of an ethylene-propylene diene rubber compound (e.g., commercially available from DuPont-Dow Elastomers under the designation Nordel IP ®),

wherein the total amount of the components (a), (b), (c) and (d) in the resin composition is 100 parts by weight.

In both of these preferred embodiments of the invention, polyisobutylene may be used in place of the ethylene-propylene diene elastomer compound. Likewise, polystyrene-based styrene-butadiene elastomers having different butadiene contents with similar effects may be used.

The components of the adhesive composition of the invention preferably provide certain properties to the final adhesive. The low melting polyolefin, such as polyethylene or ethylene-vinyl acetate copolymer, enhances the low activation temperature properties of the adhesive, the graft polymer contributes primarily to the excellent adhesion of the adhesive composition to the metal substrate, the elastic component enhances the peel resistance and increases the toughness of the final adhesive composition, and finally the polystyrene component provides excellent cohesive failure properties and surprisingly higher adhesion properties.

The melt flow rate of preferred adhesive compositions of the invention-measured according to ASTM-1238E-can be between 0.1 and 100dg/min, more preferably 0.5 to 50dg/min and most preferably 0.8 to 25 dg/min. The melting peak measured according to DSC can be between 55 ℃ and 140 ℃, depending on the composition.

When the preferred adhesive compositions of the invention are processed into films and bonded at low temperatures, they are useful in the manufacture of profiled sheets of aluminum and steel due to their unique combination of high peel strength and low surface tack.

Examples

The following examples show the surprising advantage of using polystyrene based materials, such as High Impact Polystyrene (HIPS), in providing additional peel strength, cohesive failure mode, and a tack-free adhesive film.

Example 1

Table 1 shows compositions 1A, 1B and 1C containing 0, 10 and 20 weight percent high impact polystyrene ("HIPS")% by weight, respectively. First, these compositions were dry blended and fed into a small co-rotating (co-rotating) twin screw extruder. The melt compounded material was pelletized and then blown into a film having an average thickness of about 75 microns. The film was then used as an adhesive layer to produce a 5-layer composite structure as shown in figures 1a and 1 b. The aluminum was treated with aludyne and had a thickness of 0.38 mm. The polyethylene core used was a 2mm thick sheet of Low Density Polyethylene (LDPE).

The lamination of the structure was carried out in the following electric hot press (fig. 1a and 1 b):

1-preheating the five-layer structure at 100 ℃ for 4.5 minutes,

2-application of 5kgf/cm at 135 ℃²The pressure of (a) is maintained for 20 seconds,

3-releasing the pressure and allowing the composite to remain in the press at 135 ℃ for a further 1.5 minutes,

4-air cool the sample to room temperature.

The composite structure was then tested using an Instron^TMThe peel strength was measured (ASTM 1876). The following conditions were used in the peel strength test:

i) cross extrusion speed (crosscut speed): the thickness of the glass is 100mm/min,

ii) peeling mode: 180 degrees

The last two columns of Table 1 show the peel strength results and failure mode as the amount of component d (HIPS) is increased from 0% to 20% by weight. Comparing composition 1A with compositions 1B and 1C, the surprising effect of increased peel strength due to the presence of the polystyrene HIPS component can be seen. It is also highly desirable to achieve cohesive failure (50/50 for polyethylene and aluminum, respectively). Sample 1C exhibited 80% cohesive failure compared to the adhesive failure of the other two compositions.

Table 1: single layer Ethylene Vinyl Acetate (EVA) based adhesives

Serial number	Component (a), by weight%	Component (b), by weight%	Component (c), by weight%	Component (d), by weight%	Component (e), by weight%	Peel strength, kilogram force/25 mm	Failure mode
								1A	49.9	30.0	20.0	0.0％	0.1	16.4	Bonding to aluminium
1B	39.9	30.0	20.0	10.0	0.1	23.6	Bonding to aluminium
								1C	29.9	30.0	20.0	20.0	0.1	29.8	80% tack

Ethylene-vinyl acetate (EVA) copolymer having a VA content of 12% and MI of 2.5dg/min as component (a)

Component (b) ═ Linear Low Density Polyethylene (LLDPE) grafted with 0.9% by weight of maleic anhydride and having an MI of 2.5dg/min

Ethylene/propylene/norbornadiene copolymer (EPDM) elastomer having a mooney (mooney) viscosity of 20 as component (c)

Component (d) ═ polybutadiene impact-modified polystyrene (HIPS) elastomer

Component (e) ═ hindered phenol antioxidant stabilizer

Example 2

Samples were prepared as described in example 1, except that a co-extruded blown film of polyethylene/adhesive was made and replaced with a pure adhesive film (in order to reduce the cost of the adhesive used). Compositions 2A, 2B and 2C were co-extruded with Linear Low Density Polyethylene (LLDPE) to produce LLDPE-adhesives (thickness of each layer 25 microns). The results are summarized in table 2. From the comparison of 1C to 2A (29.8 and 16.5kgf/25mm, respectively), it can be seen that coextruded films generally yield lower peel strength, but are still functional. The addition of high impact polystyrene (2C) at a content of 30% by weight reduces the peel strength. This latter composition is still functional, although not optimal.

Table 2: 2-layer Ethylene Vinyl Acetate (EVA)/polyethylene based adhesive

Serial number	Component (a), by weight%	Component (b), by weight%	Component (c), by weight%	Component (d), by weight%	Component (e), by weight%	Peel strength, kilogram force/25 mm	Failure mode
								2A	29.9	30.0	20.0	20.0	0.1	16.4	100% adhesion
2B	44.9	20.0	15.0	20.0	0.1	17.5	100% adhesion
								2C	34.9	20.0	15.0	30.0	0.1	10.9	100% adhesion

Metallocene ethylene-butene copolymer having density of 0.905 and MI of 4.5dg/min as component (a)

Component (b) High Density Polyethylene (HDPE) grafted with 1.0% by weight of maleic anhydride and having an MI of 11dg/min

Ethylene/propylene/norbornadiene copolymer (EPDM) copolymer having a mooney (mooney) viscosity of 20 as component (c)

Component (d) ═ polybutadiene impact-modified polystyrene (HIPS) elastomer

Component (e) ═ hindered phenol antioxidant stabilizer

Example 3

In this example, a metallocene linear low density polyethylene was used as a base resin to produce a composition. Table 3 summarizes the compositions. Samples 3A, 3B and 3C were prepared in a manner similar to that described in examples 1 and 2. To more closely simulate real commercial products, the latter two compositions 3D and 3E were prepared in a two-step process. 3D and 3E Adhesives were initially charged at a temperature of 149 deg.C, using 8.5kgf/cm²Was laminated to the aluminum over a period of 30 seconds. These pre-laminated aluminum sheets were then subjected to heat treatment at 132 ℃ using 8.5kgf/cm²Is pressed with the preheated LDPE core material for 10 seconds. A 90 degree peel test was performed as opposed to the 180 degree angle used in the other examples. Composition 3D is a repeat of 3C for comparison of performance between different lamination and test methods. Sample 3D represents a much lower peel strength than 3C, since 3D was subjected to a 180 degree peel test, while the 3C sample was subjected to a 90 degree peel test.

Again increasing the amount of impact modified polystyrene (HIPS) from 0 wt% to 20 wt% (compare samples 3A to 3C) resulted in a significant increase in peel strength. The failure mode is also improved and becomes more adhesive. Sample 3E, which contained 30% HIPS, exhibited a high peel strength value (20.5 kgf/25mm in 90 degree peel mode) and 100% cohesive failure. It should be noted that when such a "low lamination temperature" of about 132 ℃ is used, the products typically used in commercial production are completely destroyed.

Table 3: metallocene LLDPE based adhesives

Serial number	Component (a), by weight%	Component (b), by weight%	Component (c), by weight%	Component (d), by weight%	Component (e), by weight%	Peel strength, kilogram force/25 mm	Failure mode
								3A	59.9	20.0	20.0	0.0	0.10	N/A	Bonding with aluminium
3B	49.9	20.0	20.0	10.0	0.10	26.9	Bonding with aluminium
								3C	39.9	20.0	20.0	20.0	0.10	36.3	20% tack
3D	39.9	20.0	20.0	20.0	0.10	18.6	30% tack
								3E	29.9	20.0	20.0	30.0	0.10	20.5	100% adhesion

Metallocene ethylene-butene copolymer having density of 0.905 and MI of 4.5dg/min as component (a)

Component (b) High Density Polyethylene (HDPE) grafted with 1.0% by weight of maleic anhydride and having an MI of 11dg/min

Ethylene/propylene/norbornadiene copolymer (EPDM) elastomer having a mooney (mooney) viscosity of 20 as component (c)

Component (d) ═ polybutadiene impact-modified polystyrene (HIPS) elastomer

Component (e) ═ hindered phenol antioxidant stabilizer

While the invention has been shown and described with respect to the preferred embodiments, it will be understood by those skilled in the art that other changes, modifications, additions and deletions may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (16)

1. A resin composition having adhesive properties and produced by mixing starting materials comprising:

(a)20-60 parts by weight of linear low density polyethylene;

(b)10-30 parts by weight of maleic anhydride grafted polyethylene;

(c)10-35 parts by weight of high impact polystyrene;

(d)0 to 30 parts by weight of an elastomer selected from the group consisting of ethylene-propylene diene elastomers, polyisobutylene and polyisobutylene styrene-butadiene elastomers; and

(e) optionally minor amounts of additives selected from primary and secondary antioxidants, stabilizers, slip additives, antiblock additives, dyes and pigments;

wherein the total amount of the components (a), (b), (c), (d) and (e) in the resin composition is 100 parts by weight, and the addition of the additive does not adversely affect the adhesive properties of the resin composition.

2. The resin composition of claim 1, wherein the maleic anhydride grafted polyethylene is selected from the group consisting of maleic anhydride grafted high density polyethylene, maleic anhydride grafted linear low density polyethylene, and maleic anhydride grafted low density polyethylene.

3. The resin composition of claim 1 or 2, wherein the elastomer is an ethylene-propylene diene elastomer.

4. The resin composition of claim 3, comprising 10 to 25 parts by weight of an ethylene-propylene diene elastomer.

5. A resin composition having adhesive properties and produced by mixing starting materials comprising:

(a)40-60 parts by weight of an ethylene-vinyl acetate copolymer;

(b)10 to 30 parts by weight of a maleic anhydride grafted linear low density polyethylene or a maleic anhydride grafted low density polyethylene;

(c)10-35 parts by weight of high impact polystyrene;

(d)0 to 30 parts by weight of an elastomer selected from the group consisting of ethylene-propylene diene elastomers, polyisobutylene and polyisobutylene styrene-butadiene elastomers; and

(e) optionally minor amounts of additives selected from primary and secondary antioxidants, stabilizers, slip additives, antiblock additives, dyes and pigments;

wherein the total amount of components (a), (b), (c), (d) and (e) in the resin composition is 100 parts by weight, and the addition of the additive does not adversely affect the adhesive properties of the resin composition.

6. The resin composition of claim 5 wherein the ethylene vinyl acetate copolymer contains 3 to 40 weight percent vinyl acetate.

7. The resin composition of claim 5 or 6, wherein the ethylene-vinyl acetate copolymer contains 5 to 30% by weight of vinyl acetate.

8. The resin composition of claim 5 or 6, wherein the elastomer is an ethylene-propylene diene elastomer.

9. The resin composition of claim 8, wherein the ethylene-propylene diene elastomer is contained in an amount of 10 to 25 parts by weight.

10. An adhesive composition comprising the resin composition according to any one of claims 1 to 4.

11. An adhesive composition comprising the resin composition according to any one of claims 5 to 9.

12. The adhesive composition of claim 10 or 11 having a melt flow rate of between 0.1 and 100dg/min as measured according to ASTM-1238E; the melting peak measured according to DSC is between 55 ℃ and 140 ℃.

13. The adhesive composition of claim 12 having a melt flow rate between 0.5 and 50dg/min as measured according to ASTM-1238E.

14. The adhesive composition of claim 13 having a melt flow rate between 0.8 and 25dg/min as measured according to ASTM-1238E.

15. A composite structure comprising

(a) A metal substrate;

(b) a polymer layer; and

(c) a layer of the adhesive composition of claim 10 between the metal substrate and the polymer layer.

16. A composite structure comprising

(a) A metal substrate;

(b) a polymer layer; and

(c) a layer of the adhesive composition of claim 11 between the metal substrate and the polymer layer.