DE1719127A1 - Adhesives - Google Patents

Description

DR.-ING. BY KREISLER DR.-ING. SCHONWALD DR.-ING. TH. MEYER DR. FUES

The BP Goodrich Company, 5OO South Main Street, Akron, Ohio 44318 (USA)

ADHESIVE COMPOUNDS

The invention relates to an adhesive, in particular an adhesive, which is suitable for applications in construction and which is a polyepoxide, a polyvinyl acetal resin and a nitrile rubber or contains a polyacrylate and a polyepoxy hardener.

Assembly adhesives (structural adhesives) are those that fulfill load-bearing functions or extreme environmental conditions exposed to, for example, heat, cold, etc. The adhesives according to the invention are particularly suitable for such applications suitable. They have been found to be excellent for metal-to-metal bonds, particularly around metal sheets and joining the honeycomb interiors of metal honeycomb structures to make sandwich panels, such as they are used, for example, in the manufacture of plug-in tools.

In the past, various adhesives have been produced with which the aforementioned metal-to-metal bonds are bonded However, most of them are made with one or more physical or chemical Disadvantages. Show the masses according to the invention

in many respects not the deficiencies inherent in the assembly adhesives known to date, and they also show superior adhesion at low temperatures up to temperatures of at least 150 ^° C. The adhesives of the invention are also distinguished by very good resistance to heat and water. The adhesives can also be processed into mixtures which can be calendered to give films or thin sheets of uniform thickness.

The adhesives according to the invention suitable for assembly purposes contain four essential components: a polyepoxide, a Polyvinyl acetal and a small amount of a nitrile rubber or a polyacrylate and a polyepoxy hardener.

The epoxies used according to the invention are compounds that

contain two or more "\" groups. You can

- ο - ο -

saturated or unsaturated, aliphatic, cycloaliphatic, aromatic or heterocyclic and may optionally be substituted with non-interfering substituents, for example Chlorine atoms, hydroxyl groups, ether residues and the like. They can also be monomeric or polymeric.

The monomeric polyepoxide types can be obtained by the following bindings are illustrated:

Vinylcyclohexene-dioxide, epoxidized glycerides, butadiene-dioxide, 1,4-bis (2,3-epoxypropoxy) -benzene, 1,3-bis- (2,3-epoxypropoxy) -

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benzene, 4,4'-bis (2, 5-epoxypropoxy) -diphenylether, 1,8-bis- (2,3-epoxypropoxy) -octane, 1,4-bis (2,3-epoxypropoxy) -cyclohexane, 4,4'-bis (2-hydroxy-5 # 4-epoxybutoxy) -diphenyl-dimethylmethane, 1,3-bis (4,5-epoxypentoxy) -5-chlorobenzene, 1,4-bis (3 * 4-epoxybutoxy ) -2-chlorocyclohexane, diglycidyl ether, 1,3-bis (2-hydroxyl-5,4-epoxybutoxy) benzene, 1,4-bis (2-hydroxy-4,5-epoxypentoxy) benzene, 1,2, 5 »6-Diepoxy-5-hexyne, 1, 2,5j6-Diepoxyhexane, 1,2,3,4-Tetra (2-hydroxy-3,4-epoxybutoxy) -butane and * m epoxy-substituted materials, which one by reacting diisocyanates with glycidol, for example compounds of the formula

CH ₂ -CH-CH ₂ -OCNRNCO-CHg-CH-CHg

wherein R is a divalent organic radical with preferably 1 to 3 carbon atoms is obtained. Other examples include epoxidized esters of polyethylenically unsaturated Monocarboxylic acids, e.g. epoxidized linseed oil, soybean oil and dehydrated castor oil, monoglycerides of tung oil fatty acids, monoglycerides of soybean oil, sunflower oil and the same.

Another group of polyepoxides which can be used in accordance with the invention include the epoxidized Esters of unsaturated monohydric alcohols and polycarboxylic acids, for example di (2,3-epoxybutyl) adipate, di (2,3-epoxybutyl) oxalate and di (3,4-epoxybutyl) citrate. Among the preferred Compounds of this group include the glycidyl esters, for example the glycidyl esters of dicarboxylic acids, which are preferred

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wise contain 2 to 18 carbon atoms, for example diglycidyl phthalate, diglycidyl maleate, diglycidyl adipate and like that.

Another group of polyepoxides includes the epoxidized esters of unsaturated alcohols and unsaturated carboxylic acids, for example 2, j5-epoxybutyl-j5,4-epoxypentanoate.

To yet another group of epoxy group-containing compounds include the epoxidized derivatives of polyethylenically unsaturated polycarboxylic acids, for example dimethyl-8,9,12, 13-diepoxyeiconsandioate and diethyl-5 »6,10, ll-diepoxyoctadecyl succinate.

Yet another group includes the epoxidized polyesters, which are obtained by reacting an unsaturated polyhydric alcohol and / or an unsaturated polycarboxylic acid or anhydride groups, for example the polyester that is obtained by Implementation of 8,9,12,15-eicosadiene dicarboxylic acid with ethylene glycol is obtained.

The epoxidized polyethylene belong to yet another group unsaturated hydrocarbons, for example epoxidized 2,2-bis (2-cyclohexenyl) propane, epoxidized vinylcyclohexene and epoxidized dimeric or cyclopentadiene.

This also includes the glycidyl polyethers of polyhydric phenols, which are obtained by reacting a polyhydric phenol with an excess of a halogen-containing epoxy in

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an alkaline medium. For example, 2,2-bis (2,3-epoxypropoxyphenyl) propane is obtained by reacting Bis-phenol, (2,2-bis (4-hydroxyphenyl) propane), with an excess of epichlorohydrin. Other polyhydric phenols that can be used for this purpose include resorcinol or polynuclear phenols, for example 2,2-bis (4-hydroxyphenyl) ' butane, 4,4'-dihydroxybenzophenone, bis (4-hydroxylphenyl) ethane and 1,5-dihydroxynaphthalene. Examples of the halogen-containing Epoxides are also j} -chloro-l, 2-epoxybutane, 5-bromo-l, 3-epoxyhexane, 3-chloro-1,2-epoxyoctane and the like.

The polymeric polyepoxide types include, for example Polyejöpoxypolyhydroxy-polyäther, which can be obtained by reaction, preferably in an alkaline or an acidic medium, a polyhydric alcohol or a polyhydric phenol with a polyepoxide receives, for example the reaction product of glycerol with bis (2,3-epoxypropyl) ether, the reaction product of sorbitol with bis (2,2-epoxy-2-methylpropyl) -ether, the reaction product of pentaerythritol and 1,2-Bpoxy-4,5-epoxypentane, the reaction product of bis-phenol with bis (2,3-epoxy-2-methylpropyl) ether, the reaction product of resorcinol with bis (2, j5-epoxypropyl) ether and the reaction product of catechin and bis (2,2-epoxypropyl) ether.

Another group of polymeric polyepoxides includes the hydroxyl-substituted polyepoxydpolyethers, which one by Reaction, preferably in an alkaline medium, with a slight excess, for example with a 0.5 to j5 molar excess Excess of a halogen-containing epoxy as described above with any of the above-described polyvalent

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Sometimes phenols, for example resorcinol, catechol, bis-phenol, bis (2,2 ^f -dih * ydroxydinaphthyl) methane and the like, are obtained.

This group also includes the polyepoxy polyethers, which are obtained by reaction, preferably in the presence of a acidic compound, for example hydrofluoric acid, one of the above-mentioned halogen-containing Epoxies with a polyhydric alcohol, for example glycerine, propylene glycol, ethylene glycol, trimethylene glycol, butylene glycol and the like, and then treating the obtained product with an alkaline compound ».

Another group of polyepoxides includes the epoxylated Novalace of the following idealized structural formula:

0 -

2 - CH - CHg

0-CH ₂ -CH - CH ₂

0-CH ₂ -CH

wherein η has a value from 0 to about 5, preferably from 0 to 2 represents.

Other polymeric polyepoxy compounds include the poly

-Group merizates and copolymers of Εροχχ / containing monomers, which contain at least one polymerizable ethylene bond. If this type of monomer is polymerized in the absence an alkaline or acidic catalyst, for example in the presence of heat, oxygen, peroxide compound, actinisohem

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Light and the like, addition polymerization takes place at the multiple bonds, leaving the epoxy groups unaffected stay. These monomers can be polymerized with themselves or with other ethylenically unsaturated monomers be, for example with styrene, vinyl acetate, methacrylonitrile, acrylonitrile, vinyl chloride, vinylidene chloride, methyl acrylate, Methyl methacrylate, diallyl phthalate, vinyl allyl phthalate, divinyl adipate, Chlorallyl acetate and the like. Examples of this Polymers are poly (allyl-2, j5-epoxypropyl ether), poly (2,3-epoxypropyl crotonate), Allyl- ^ I-epoxypropylether-styrene-Copolymerisfc, Poly (vinyl-2,3-epoxypropyl ether), allyl glycidyl ether-vinyl acetate copolymer and polyC ^ -glycidyloxystyrene).

Particularly useful for the purposes of the invention are the low molecular weight, liquid glycidyl polyethers of divalent ones Phenols obtained by reacting epichlorohydrin with a dihydric phenol in an alkaline medium. The monomers Products of this type can be found by the general formula

⁰ - J *

CH ₂ -OH - CH ₂ - 0 - P - 0 - CH ₂ - CH - CHg

illustrate where P is a divalent hydrocarbon fre of dihydric phenol. The polymeric products are generally not a single simple molecule, but rather represent a complex mixture of general glycidyl polyethers formula

0 ^ O

Cu ₂ - CH - CH ₂ - O (P - 0 - CH ₂ - CHOH - CH ₂ O) _n PO-CH ₂ CH - CH ₂

represents, wherein P is a divalent hydrocarbon radical of the

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Dihydric phenol is 1 and η is an integer from the series 0, 1, 2, J5, etc., preferably 1, denotes. It is true that η is for a single molecule of polyether is an integer, but the fact that polyether is in the form of a mixture of compounds is obtained causes the determined value for η to be an average value which is not necessarily 0 or a must represent an integer. The polyethers can, in some cases, contain a very small amount of compounds in where one or both of the terminal glycidyl residues are hydrated Form.

Still other specific types of polyepoxides that are useful in the present invention are diisodecyl-4,5-epoxytetrahydrophthalate, epoxidized soybean oil and compounds of the following structure:

CH
ι

H, C

and

-CH ₂ -CH-CH-CH ₂ -CH ₂ CH-CH-CH ₂ CH ₂ CH-CH-CH ₂ CH ₂ Ch-CH ₂ -CH

OH 0 CH

C = O CH,

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The last-mentioned polymer has a hydroxyl group content of about 2.5, a viscosity of about 1,800 P at 20 ⁰ C, an iodine value of about I85 and an epoxy content of about 9; the index χ preferably denotes the number one.

The polyvinyl acetal resin component used according to the invention Is not limited to any particular type of polyvinyl acetal resin. This component can according to conventional methods from polyvinyl acetate by hydrolysis and subsequent reaction with a Aldehyde can be produced with the formation of the acetal. Such methods are described, for example, in U.S. Patent 2,307,588 described. In general, the polyvinyl acetal resins are made using low molecular weight aldehydes, for example formaldehyde, Acetaldehyde and butyraldehyde. According to the invention, the polyvinyl acetal resin used is preferably polyvinyl formal,

as it is an adhesive with great toughness and heat resistant
ability / gives.

In order to avoid ambiguity with regard to the term acetal resins, it is stated that under the term "polyvinyl acetal resin" understood to mean resins made using low molecular weight aldehydes. When it is desirable is that KLyvinylacetal resin, which has been produced from acetaldehyde, to denote, one uses the sub-term "Polyvinylacetal Acetaldehyde". The other specialty polyvinyl acetal resins are referred to by their common names. For example is the polyvinyl acetal resin made using Formaldehyde, simply called polyvinyl formal.

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The rubbery component can be a nitrile rubber or a polyacrylate. Both groups are described below.

The nitrile rubbers include copolymers of a butadiene (1,3) hydrocarbon and an α-methylene trile. Butadiene (1,3 ^ hydrocarbons include, for example, butadiene (1,3), 2-methylbutadiene (1,3) (isoprene), 2,3-dimethylbutadiene (1,3) (piperylene). (1,3) is preferred. A-methylenenitriles that can be substituted, for example, include acrylonitrile, methacrylonitrile, ethacrylonitrile and oc-chloroacrylonitrile. Acrylonitrile is the preferred nitrile. The amount of bound a-methylenenitrile in the copolymer can be from about .% vary 100 parts by weight of the copolymer A copolymer having about 40 wt .- # bound a-Methylennitril is preferred Minor amounts of other comonomers which are other than the butadiene the (1,3 - 15 to 45 wt.. ) hydrocarbons and the α-methylenenitrile can optionally also be used. Such other comonomers include styrene, methyl methacrylate, ethyl acrylate, vinylidene chloride, acrylic acid, methacrylic acid, maleic acid, acrylamide and others.

The polyacrylates are polymers which consists of about 5 to 100 wt .- ^ o at least one Acrylesters and 0 to 50 wt -% of at least one other polymerinierbaren monomers have been prepared.. Acrylic ester monomers that can be used include those

LI

the general structural formula ι, wherein the

H ₂ C = C - COOR

R represents an alkyl radical with 1 to 18 carbon atoms.

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Among the polyacrylates used herein therefore include homopolymers of a Acrylesters, copolymers and interpolymers of at least 50 wt .- ^ Acrylesters at least one and up to 50 wt -.% Of one or more of various other vinyl monomers which are copolymerislerbar with the Acrylestern.

Among the various other vinyl monomers that interact with the acrylic ester are copolymerizable, include those

It ft

C = C and C = C-C = C groups

contain. Such vinyl monomers include vinyl halides, for example vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride, Vinylidene bromide, vinylidene fluoride, chlorotrifluoroethylene, Trichlorethylene, 1,2-dichloroethylene and the like; the acrylate esters, for example phenyl acrylate, cyclohexyl acrylate, 2-cyanoethyl acrylate, 2-hydroxyethyl acrylate and the like; the methacrylate esters, for example phenyl methacrylates, cyclohexyl methacrylates, 2-hydroxyethyl methacrylate, 2-cyanoethyl methacrylate, Cellosolve methacrylate and the like; the dienes, for example butadiene (1,3), butadiene (1,3), the one in the 2-position by a halogen atom or an alkyl group having 1 to 4 carbon atoms is substituted, butadiene (1,3), which is in the 2- and 3-position with halogen atoms and alkyl groups with 1 to 4 carbon atoms is substituted (such substituted 1,3-butadienes include 2,3-dimethyl-butadiene- (1,3) * 2,3-dichlorobutadiene- (1,3), 2-methyl-3-chloro-butadiene- (1,3) and the like); the vinyl cyanides, for example acrylonitrile, methacrylonitrile, Vinylideneoyanide, fumaronitrile, maleonitrile and the like and other; the maleate esters, for example dimethylraaleate, diethy1-

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fumerate, the dipropyl maleates, the dibutyl maleates, the diamyl maleates, the dihexyl maleates, dicyclohexyl maleate, diphenyl maleate and the same; the fumarate esters, for example dimethyl fumarate, Diethyl fumarate, the dipropyl fumarate, the dibutyl fumarate, the Diamyl fumarate, the dihexyl fumarate, dicyclohexyl fumarate, diphenyl fumarate and the same; the vinyl esters, for example vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl laurate, Isopropenyl acetate, isopropenyl caproate and the like) the vinyl aldehydes, for example acrolein and methacrolein; the vinyl amides, for example acrylamide, methacrylamide, N-methylacrylamide and the same; the vinyl carboxylic acids, for example acrylic acid and methacrylic acid, the vinyl pyridines, for example 2-vinyl pyridine, 4-vinyl pyridine, 4-vinyl pyridine, 2-methyl-5-vinyl pyridine and the same; the vinyl aromatics, for example styrene, α-methyl styrene, chlorine-substituted styrene, the vinyl toluenes, the vinyl xylenes, vinyl naphthalene, and the like; the monoolefins, for example ethylene, propylene, the butylenes, the amylenes, the hexylenes, cyclohexene and the like; the vinyl ethers, for example Vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether, vinyl amyl ether, vinyl hexyl ether, the vinyl heptyl ethers, vinyl octyl ethers, vinyl cyclohexyl ethers, vinyl phenyl ethers, vinyl benzyl ethers and the like; the Allyl esters and ethers, for example allyl acetate, allyl laurate, allyl benzoate, ally Inte thyl ether, allyl ethyl ether and the like; the vinyl ketones, for example vinyl methyl ketone, vinyl ethyl ketone, Isopropenyl ketone and the like.

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- 13 -

The preferred polyacrylates are the homopolymers of

H acrylic ester monomers of the general formula HpC = C - COOR,

wherein R represents an alkyl radical having 1-4 carbon atoms.

The polyepoxy curing agents can be any material that will react with the epoxy groups. Such materials include for example amines, polyamides containing amino groups, acids, acid anhydrides, salts, mercaptans, hydrazines, boron trifluoride complexes and the like and mixtures thereof. Specific examples include, among others, p-phenylenediamine, Diaminodiphenyl sulfone, ρ, ρ'-methylenedianiline, p, p-diaminodiphenylmethane, Triaminobenzene, 2,4-diaminotoluene, tetraaminobenzene, 3 »3'-diaminodiphenyl,!, JJ-diamino-ty-isopropylbenzene, !, ^ - Diamino- ^ S-diethylbenzene, diaminostilbene, triethylamine, Ethylenediamine, diethylamine, diethylenetriamine, triethylenetetramine, tetraethylene pentamine, pyridine, diaminopyridine, piperidine, Imidazole, a-ethyl - ^ - methylimidazole, N, N'-diethyl-1,3-propanediamine, Dicyandiamide, melamine, fatty acid salts of amines, for example the 2-ethylhexoate of tris (dimethylaminomethyl) phenol, the adducts of polyepoxides (which will be described below) and the mono- and polyamines described above, for example the adduct of p-phenylenediamine and styrene oxide and the adduct of p-phenylenediamine and allyl glycidyl ether, the adduct of diglyoidyl ether of 2,2-bis (4-hydroxyphentyl) propane and diethylenetriamine, the adduct of diethylenetriamine and ethylene oxide, the adduct of diethylenetriamine and styrene oxide, the adduct of polyamines and unsaturated nitriles, for example the adduct of diethylenetriamine and acrylonitrile,

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the adducts of diethylenetriamine and unsaturated sulfolanes and the adduct of p-phenylenediamine and acrylonitrile.

Other examples include the amino group-containing polyamides described in U.S. Patent 2,450,940 and the monomeric amides described in U.S. Patent 2,832,799.

Other examples include acid anhydrides such as phthalic anhydride, succinic anhydride, dodecenylsuccinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, pyromellitic anhydride, Hexachlorphthalsäureanhydrid, Mdhyl- "Nadic ^M anhydride, the anhydrides of which one, turpentine, long-chain unsaturated by reacting maleic anhydride with unsaturated compounds, for example oils Acids and the like, and anhydrides obtained by reacting long-chain acids with acetic anhydride, and the like.

Still other examples include the salts, e.g. magnesium perchlorate, Zinc fluoborate, potassium persulfate, copper fluoroborate, copper (II) arsenate, zinc persulfate, copper (II) fluosilicate, Copper (II) iodate, copper (II) sulfate, magnesium nitrate, Magnesium phosphate, stannous fluorate, zinc nitrate and the like as well as the chloride derivatives, for example aluminum chloride, zinc chloride, iron (III) chloride and the like.

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Other examples include the acids and acid esters of both organic and inorganic acids, for example the sulfonic acids and their salts as described in the United States patents 2,687,397, 2,643,243 and 2,631,138 are described, the phosphoric acid esters as described in US Pat. No. 2,554l; oxalic acid as described in US Pat. No. 2,500,449 described long-chain acids, for example adipic acid, succinic acid, acids obtained by polymerization of unsaturated Acids, such as the long-chain fatty acids, e.g. linoleic acid, Soybean fatty acids. Acids obtained by polymerization unsaturated acids such as acrylic acid with itself or with other materials, for example butadiene, styrene, acrylonitrile and the like, and polyesters containing acid groups, which are obtained, for example, by reacting polycarboxylic acids, such as phthalic acid, terephthalic acid and the like, with an insufficient amount of a polyhydric alcohol,

Ethylene
for example / glycol, propylene glycol and the like.

Further examples include the Bortrifluorld adducts with a wide variety of materials, for example with amines, Amides, ethers, phenols and the like. Examples of such adducts are described in U.S. Patent 2,824,083.

Still other examples include the polymercaptans, for example 1,5-petanedithiol, 1,4-cyclohexanedithiol, dimerkapto-diethyl formal, 3,3'-thiodipropanethiol, 4,6-disulfonyl-1,8-ootan

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dithiol, 1,3-benzenedithiol, tetrahydropyran ^ J-dlpropanthiol, Furan-2,5-dibutanethiol, and the polymeric polythiols, for example the polythiopolymercaptans obtained by treating the aforementioned polymercaptans with agents, for example Hydrogen peroxide. Polymers of the formula

HS (C ₂ H ₄ OCH ₂ OC ₂ H ₄ SS) _n C ₂ H ₄ OCH ₂ OC ₂ H ₄ SH

can be obtained by reacting Dimerkaptodiethylformal with hydrogen peroxide. A more detailed description of the production of such polymers can be found in US Pat. No. 2 * 66,963.

Preferred hardeners are the amine-type hardeners, dicyandiamide, if it is desired to harden the adhesive composition according to the invention at higher temperatures of around 175.degree. The preferred curing agents which are used when it is desired to cure at lower temperatures around 120 ⁰ C, include aliphatic polyamines such as diethylenetriamine, Triäthylentetraamin and 2-ethyl-4-methylimidazole. If curing is to take place at room temperature, it has been found that polyamine diethylaminopropylamine is useful.

A valuable adhesive can be obtained from about 25 to 80 parts by weight of polyepoxide, 64 to 10 parts by weight of polyvinyl acetal resin and 1 to 10 parts by weight of a rubbery compound, selected from the group of nitrile rubber and polyacrylates (100 parts by weight each of polyepoxide, polyvinyl acetal resin and the rubber-like compound) together with about 1 to 15 parts by weight Polyepoxide hardener.

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Preferred adhesives which are used for the production of calendered film or film. Pollen useful contain about 50 to 65 parts by weight Polyepoxide, about 48 to 25 parts by weight of polyvinyl acetal and about 2 to 10 parts by weight of the rubber-like compound (per 100 parts by weight Parts of polyepoxide, polyvinyl acetal resin and the rubber-like compound) in addition to about 1 to 15 parts by weight of the polyepoxide hardener.

The particularly preferred adhesives which are particularly useful for producing calendered foils or films contain about 55 to 60 parts by weight of polyepoxide, about 40 to 55 parts by weight Polyvinyl acetal and about 4 to β parts by weight of the rubber-like compound (per 100 parts by weight of polyepoxide, polyvinyl acetal resin and the rubbery compound) in addition to about 5 to 7 parts by weight of the polyepoxide hardener.

The adhesive according to the invention can be produced in various forms. It can be in the form of a paste, as cement in a suitable solvent, as an extruded rod, and among other shapes in the form of a strapless or supported one Foil can be produced.

If the adhesive according to the invention is desired in the form of a film which is suitable for assembly adhesive purposes, must the film will be smooth, of uniform thickness and free from surface imperfections. It is also desirable that the Foil does not stick.

In general, a useful film can be made from the inventive film Produce adhesive by simply using the chewed

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schuk-like compound, that is, the nitrile rubber or the polyacrylate dispersed in a mixture of the other components and the material obtained is then transferred into a film.

It has been found that an acceptable film can be produced from the adhesive of the invention by the following process. First of all, the polyvinyl acetal resin and the polyepoxide, which is preferably in liquid form, are measured together in order to wet the resin. A mechanical stirrer has proven valuable for this mixing process. The resulting mixture is then removed from the mixer and placed in another mixer, preferably equipped with an internal heating device, and mixed with heating to about 82 to 93 ° C. in order to obtain a viscous mass of uniform consistency. The rubber-like compound is then dispersed in the mixture of the polyepoxide and the polyvinyl acetal resin. A 2-roller rubber grinder is effective for this dispersion. It has also been found that the polyepoxide hardener can be added at this time, although it could also be added beforehand. During the dispersion of the rubbery compound in the components previously mixed on a 2-roll rubber grinder, a mixture temperature between about 49 and 66 ° C. must be maintained. If the temperature of the mixture rises to a temperature above about 66 ° C, the rubber-like compound is non-mixing of the other components dispersed in the G _e in Walzenbehandiung, but it forms with these components a solution. The consequence of this will continue

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described below. After the rubber-like compound has been dispersed, the material obtained can be flat Transfer foils of uniform thickness. It has been found that a 3-roll calender mill is valuable for this operation Provides service. If desired, the freshly made film can be saved for later use by removing it on a sheet or plate of a non-adhesive material, for example polyethylene, lays. It is noted that the stored film retains its shape when removed from its carrier film is. The rubber-like material, i.e. the nitrile rubber or the polyacrylates, must be used in the other adhesive materials be dispersed in the specified amount if a flat film of uniform thickness with a minimum of Surface imperfections are to be produced. It was used in the manufacture of films according to the invention Adhesive masses found that if a deficiency or an excess of the rubber-like compound is used in the adhesive is or if the rubbery compound is not dispersed in the other components of the adhesive that a Film is obtained which is not useful because it is neither flat nor uniform in thickness and various Shows surface flaws.

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example 1

An adhesive is prepared based on the following Recipe:

Polyepoxide ^a 53 »0

Polyvinyl formal ^b 37

Butadiene-acrylonitrile-co-

polytnerizat

(42-44 * bound acrylonitrile) 4.75

Dicyandiamide 5.25

(a) Liquid polyepoxide, produced by reacting epichlorohydrin with 2,2-bis (4-hydroxyphenyl) propane in an alkaline medium, with an epoxy equivalent of 173 to 179 (grams of resin per one gram of epoxy equivalent) and a viscosity of 3,600 up to 6,400 cP at 23 ⁰ C.

(b) Resin content: vinyl alcohol 5 to 6 wt .- #, vinyl acetate,

Weight

9.5 to 13 # 0 #, vinyl formal 81 to 85.5% by weight \ approximate average degree of polymerization (weight) 650 and average molecular weight about 34,000.

The polyepoxide and the polyvinyl formal resin are mixed in one mechanical mixer to moisten the resin. This mixed material is then transferred to an internal mixer and mix there for 20 to 30 minutes at 82 to 93 ° C, until you have obtained a viscous mass of uniform consistency.

The mixture obtained is placed on a 2-roll grinder, the runs at slow speed and is cooled with water to maintain a mixture temperature of 49 to 66 ° C.

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The butadiene-acrylonitrile copolymer is uniformly dispersed in the polyepoxide and polyvinyl formal components. to at this time the dicyandiamide is added. The material is then run through a 3-roll calender and one is formed flat film with a thickness of 0.254 mm. The thus obtained Film is tack-free, has a uniform thickness, and is generally free from surface defects. If you heat a part the foil between two 1.6 mm thick aluminum plates (Alcad-Aluminum, 2024-T3; the overlap is 12.7 mm) 60 minutes at 177 ° C under a pressure of 0.55 to 1.76 kg / cm for tensile-shear stress tests, this is how you get a strong bond. The tensile shear strength of a 2.5 ^ cm test piece shows the following values:

- 55 ° C 398.6 kg / cm ²

24 ° C 436.9 kg / cm ²

82 ⁰ C 423.6 kg / cm ²

121 ° C 248.9 kg / cm ²

149 ° C 115.3 kg / cm ²

Example 2

Another film is produced according to the procedure described in Example 1, with the exception that one Butadiene-aryinitrile omits. The film obtained is not smooth but is a wrinkled, blistered material that is unacceptable for use as a mounting adhesive sheet.

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Example 3

A mixture of polyepoxides is used to produce an adhesive according to the following recipe:

Polyepoxide 26.5

Polyepoxide ^c 26.5

Polyvinyl formal ^b 37.0

Butadiene-acrylonitrile copolymer
(42-44JS bound acrylonitrile) 4.75

2-ethyl-4-methyl-imidazole 5.25

(a) The same polyepoxide as used in Example 1.

(b) The same polyvinyl formal as used in Example 1 became.

(c) A liquid polyepoxide of the following structural formula

" ₂ A" - c " ₂ - ο -

with an epoxy equivalent of about 125 (grams of resin per one gram equivalent Epoxy).

The ingredients are mixed according to the procedure described in Example 1, treated on the roller mill and in Slides transferred. The film obtained shows a smooth, tack-free film Surface and uniform thickness. The test bodies are placed between them by heating a piece of film for 30 minutes

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two 1.6 mm thick aluminum pieces (Alcad aluminum 2024-T3J the overlap is 12.7 mm) at 107 ⁰ C under a pressure from 0.35 to 1.7 $ kg / cin ² ago. The tensile shear strength of a 2.54 era test body shows the following values:

-55 ° C 313.9 kg / cra ²

24 ° C 310.0 kg / cm ²

82 ° C 298 ^ 8 kg / on ²

121 ° C "221.4 kg / cm ²

Example 4

Another adhesive is using according to the following recipe JÜKt of two different polyvinyl acetal resins manufactured:

Folyepoxide ^a 53.0

Polyvinylfonaal ^b 18.5

Polyvinyl butyral ⁰ 18.5

Butadiene acrylonitrile

CopolT »erisat

(42-44g bound acrylonitrile) 4.75

Dicyandiamide 5.25

<a) The same polyepoxide as used in Example 1 became.

(b) The same polyvinyl formal resin as used in Example 1 was used.

(c) Resin content: vinyl alcohol 17.5 to 20 Qex .- $, vinyl acetate

0 to 2.5 Qew · - ^, vinyl butyral about 80 Oew.-Ji; approximate average Molecular weight 100,000 to 150,000.

109832 / 13QQ

The materials are mixed in the procedure described in Example 1, treated on the roller mill and transferred into foils. The film obtained shows a uniform thickness and a tack-free, defect-free surface.

The test bodies were produced according to the procedure described in Example 1. The tensile shear strength shows the following values:

-55 ° C 562.5 kg / cm ²

24 ⁰ C 326.5 kg / cm ²

82 ⁰ C 249.0 kg / cm ²

121 ° C 97.9 kg / cm ²

149 ° C 58.1 kg / cm ²

Example 5

An adhesive is made based on the following recipe:

Polyepoxide ^a 53.0

Polyvinyl formal ^b 37.0

Ethyl acrylate chlorine

vinyl ethyl ether copoly

merisat (95/5) 4.75

Dicyandiamide 5.25

(a) The same polyepoxide as used in Example 1.

(b) The same polyvinyl formal as used in Example 1.

109832/1300

The materials of the above recipe were mixed in the manner described in Example 1 on the roller mill treated and transferred into foils. The film obtained has a smooth, tack-free surface and a uniform thickness. 2.54 cm test specimens were used to determine the tensile shear strength prepared in the manner described in Example 1. For the tensile shear strength & I gave the following values:

-55 ° C 562.1 kg / cm ²

24 ° C 386.7 kg / cm ²

82 ⁰ C 350.1 kg / cm ²

121 ° C 202.5 kg / cm ²

59.8 kg / cm ²

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Claims (12)

- 26 claims l) adhesive containing (a) about 55 to 80 parts by weight of polyepoxide, (b) about 64 to 10 parts by weight of polyvinyl acetal resin, (c) about 1 to 10 parts by weight of a rubbery compound selected from the group consisting of nitrile rubber and polyacrylate (100 parts by weight of polyepoxide, polyvinyl acetal resin and the rubbery compound) and (d) about 1 to 15 parts by weight of polyepoxide hardener. 2) adhesive according to claim 1, characterized in that the polyepoxide is liquid. J>) Adhesive composition according to claim 1, characterized in that the rubber-like compound is nitrile rubber. 4) adhesive according to claim 1, characterized in that the chews " schuk-like compound is polyacrylate. 5) adhesive according to claim 1, characterized in that the polyepoxide is a liquid, the Polyvlnylacetal resin polyvinyl formal, the rubbery compound nitrile rubber and the polyepoxide hardener a compound from the group dicyandiamide, aliphatic polyamines, 2-ethyl-4-methylimidazole and Dläthylaminopropyl is. 109832/1300 6) adhesive according to claim 5 »characterized in that the nitrile rubber is a copolymer of butadiene (1.5) and acrylonitrile is. 7) Process for producing an adhesive in film form, characterized in that one contains an adhesive (a) about 50 to 65 parts by weight of polyepoxide, (b) about 48 to 25 parts by weight of polyvinyl acetal resin, (c) 2 to 10 parts by weight of a rubber-like compound from the group consisting of nitrile rubber and polyacrylate, (per 100 parts by weight of polyepoxide, polyvinyl acetal resin and the rubbery compound and (D) about 1 to 15 parts by weight of Polye ^ fpoxyd hardener, the rubber-like compound is dispersed in the mixture of the polyepoxide, the polyvinyl acetal and the polyepoxide hardener, processed into a film. 8) Method according to claim 7 »characterized in that the polyepoxide is a liquid. 9) Method according to claim 7 *, characterized in that the rubber-like Compound is nitrile rubber. 10) Method according to claim 7, characterized in that the rubber-like Compound is polyacrylate. 11) Method according to claim 7, characterized in that the polyepoxide a liquid, the polyvinyl acetal resin polyvinyl form & l, the rubbery compound nitrile rubber and the polyepoxide hardener a compound from the group dicyandiamide, 109832/1300 aliphatic polyamines, 2-ethyl-4-methylimidazole and diethylaminopropylamine is. 12) Method according to claim 11, characterized in that the nitrile rubber is a copolymer of butadiene (1,3) and acrylonitrile. 109832/1300