JPS5832186B2 - Dou Setuchiyakuzaisoseibutsu - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to the adhesion of thermoplastic compositions to copper-containing metals, and in particular to special compositions formulated to be highly useful for such adhesion.

It is difficult to bond materials to substrates made of copper because the surface is easily oxidized and the bond is susceptible to failure due to oxygen diffusing into the adhesive and destroying the oxide layer.

Although known epoxy adhesives can be used to bond other materials to copper, a weak interlayer usually results and the bond eventually breaks down.

Prior art successes in adhering materials to copper substrates have typically been limited to clean surface copper that has been mechanically abraded or steam degreased and acid etched. .

Conventionally, an aqueous solution of ferric chloride/nitric acid is used to obtain a clean surface copper.

Copper surfaces can also be primed with silanes such as aminosilanes to improve copper adhesion.

Recent U.S. Pat. No. 3,342,647 teaches that copper sheets can be bonded by using thermally decomposed urea, formamide or hexamethylenetetramine and then applying a conventional adhesive to the active surface. are doing.

Traditional adhesives used to bond copper are polyamide-cured epoxy compounds, or Teyupon's Surlyn (
ionomer resins such as 5urlyn).

When using hot melts, nylon-type polyamides or polyhydroxyether polymers can be used.

Specially formulated acrylic acid or glycidyl acrylate grafts containing flexible (e.g. diostomeric) components can be used as steel adhesives without requiring preparation of the copper surface for sealing.

Italian Patent No. 953,632 provides novel graft polymers prepared by a novel technique and exhibiting outstanding adhesion to many substrates.

Surprisingly, it has been found that most of the compositions prepared according to the Italian patent exhibit excellent adhesion properties on a wide range of substrates, but only very low adhesion on copper.

It has now been discovered that a specially formulated, very special compound, falling within the general group described in the above specification, exhibits remarkable adhesion to copper, and forms the basis of the present invention. is formed.

In fact, in direct comparison with DuPont's Surlyn, the special products of the present invention are at least equivalent in one aspect, but vastly superior in others.

The adhesion to copper of the specific formulations described herein ranges from slightly better than Surlyn to more than twice that of Surlyn.

Generally, the specialized steel bonding thermoplastic compositions of the present invention can be divided into polyethylene-based and polypropylene-based.

When based on polyethylene, an important point regarding its formulations and compositions is that grafting either the glycidyl acrylate component or the acrylic acid component directly onto the polyethylene base without further modification of the formulation of the main components will result in copper The only problem is that only compositions with poor adhesive strength can be obtained.

In order to obtain maximum steel adhesion in polyethylene-based systems, small amounts of other elastomeric components must be included in the formulation.

Such elastomer component may be any elastomer compatible with polyethylene, but those with low unsaturation are generally preferred.

Suitable examples include ethylene-propylene copolymers, butyl rubber, polyisobutylene, ethylene-vinyl acetate, and the like.

Generally, the polyethylene-based copper adhesive compositions of the present invention contain 60-97%, preferably 80-95%, most preferably 85-92% by weight low density polyethylene, with the remaining percentage butyl rubber, polyisobutylene, or an elastomer such as ethylene/propylene copolymer.

This blend is then grafted with about 0.02 to 20% by weight, preferably 0.1 to 10% by weight, and most preferably 0.2 to 8% by weight of acrylic acid or glycidyl acrylate.

Preferably, the grafting is carried out according to the method of Italian Patent No. 953,632.

For polypropylene-based thermoplastic steel adhesive compositions, very little steel adhesion occurs unless a melt temperature of at least 260° C. is used when directly grafting or incorporating acrylic acid or glycidyl acrylate onto the polypropylene itself. All I can get is power.

An elastomeric or reactor copolymeric ethylene/propylene copolymer component or a similar elastomeric component as described above, such as butyl rubber, polyisobutylene, etc., is added in small quantities to the polypropylene base formulation, followed by either acrylic acid or glycidyl acrylate. Remarkable steel adhesion can only be obtained when grafting.

Another important consideration in the case of polypropylene-based formulations is the choice of glycidyl acrylate as the grafting monomer.

This is because under the above conditions particularly high adhesion to copper can be obtained, especially compared to standard industrial products such as Surlyn.

Generally, 60 to 97%, preferably 80 to 95%, most preferably 85 to 92% by weight of polypropylene and the balance of the elastomer or reactor copolymer are blended and then about 0.02 to 20% by weight of the polypropylene is blended. % by weight, preferably from 0.1 to 10% by weight, most preferably from 0.2 to 8% by weight, of acrylic acid, or most preferably grafted with lysidyl acrylate, onto a copper or copper alloy substrate. It was found that it adhered well.

The components of the copper adhesive composition can be friend-grafted together, or they can be grafted separately and then blended together.

Those skilled in the art can choose whichever is most convenient.

For further details please refer to the cited Italian Patent No. 9536
It is described in the specification of No. 32.

Although clearly the present invention is directed to precisely defined thermoplastic and adhesive compositions that exhibit significant adhesion to copper, an important feature of the present invention is that the preferred silver adhesive formulations are based on ethylene and propylene. The reactor contains relatively small amounts of either copolymer or elastomer components.

This apparently increases the mobility of the adhesive composition and further enhances its adhesion.

However, this phenomenon has much wider applicability to steel adhesive formulations.

Furthermore, by containing relatively small amounts of such elastomeric components, for example 2-30%, preferably 5-20%, most preferably 5-15% by weight, especially for polypropylene-based formulations, It has been discovered that formulations can be obtained in which rapid quenching, such as water immersion, to promote adhesion is unnecessary.

This is an important aspect of the technology regarding such graft compounds.

In other words, formulations based on polypropylene and high-density polyethylene containing small amounts of nidistomer components provide very good and perhaps unparalleled adhesion without the need for quenching.

Obviously, this gives tremendous economic value.

The thermoplastic adhesive compositions of the present invention can also be more precisely defined by another criterion: melt flow rate (MFR) or melt index (MI).

Generally, as this number increases, the ability of the adhesive formulation to wet the copper substrate increases.

Thus, the MFR or MI of the particular formulation used is about 1-300, preferably 2-5o, most preferably 2-5o.
Spanning a range of 35.

Glycidyl acrylate and acrylic acid monomers are particularly preferred grafting monomers for this invention, although other closely related monomers are considered equivalents.

The term "reactor copolymer" as used herein
refers to isotactic crystalline polypropylene modified by alternating or block ethylene chains during polymerization in a reactor to improve impact resistance properties at low temperatures.

The term "reactor" was added to indicate a copolymer produced without any modification (deformation) and to distinguish it from a grafted copolymer.

This is a convenient nomenclature commonly used commercially.

It should be noted that a nidistomer component can be added to the pace polymer to be an impact friend.

This impact blend is often incorrectly referred to as an impact copolymer.

The blend usually contains varying proportions of elastomers such as polypropylene, polyethylene and ethylene-propylene copolymers.

The present invention will be further illustrated by the following examples, but of course the present invention is not limited thereto.

Example 1 In this example, a series of formulations containing polyethylene were blended with or without the addition of elastomer components or reactor copolymer fractions.

Either films or pads were prepared from this formulation.

They were melted between two copper strips, then cooled and subjected to standard ASTM peel strength measurements.

The results are summarized in Table 1.

As is clear from the data in the table above, the compositions of the present invention provide excellent benefits.

Grafting acrylic acid or glycidyl acrylate directly onto polyethylene lowers the melting temperature to at least 260°C.
This is because normal conditions are not suitable for obtaining remarkable adhesion properties to copper, except when the temperature is set at .degree.

Steel adhesive formulations also bond very well to other (ferrous and non-ferrous metals) as well as to thermoplastics, thermosets, and other surfaces.

Examples of special laminates include copper and iron metals, aluminum,
Examples include lead, zinc, Mylar, nylon, nitrile polymers, wood, and glass.

Furthermore, any of the metals in the above materials can be bonded to each other by the adhesive of the present invention.

Further embodiments of the present invention include the following.

(1) The composition according to the claims, wherein the polyolefin is polyethylene.

(2) The composition according to the claims, wherein the polyolefin polymer is polypropylene.

(3) The composition according to claims 1 and 2 above, wherein the elastomer is butyl rubber.

(4) The composition according to claims 1 and 2, wherein the exl-mer is an ethylene/propylene copolymer.

(5) An article comprising a copper surface adhered to the surface of the composition of items 1 to 4.

Claims (1)

[Scope of Claims] 1. The following components: (a) 60 to 97% by weight of low-density polyethylene; and (b) the remainder is an elastomer selected from the group consisting of butyl rubber, polyisobutylene, and ethylene/propylene rubber. 1. A thermoplastic adhesive composition having significant adhesion to copper, comprising a blend of 0.02 to 20% by weight of acrylic acid.