DD258778A1 - PROCESS FOR THE PRODUCTION OF COMPOUND - Google Patents

Abstract

Compounds of thermoplastics, in particular polyolefins, and hair-hardenable polymers, in particular substituted polyacrylic acid esters, with high long-term stability and moisture resistance are to be produced. According to the invention, a prepolymer or a component of the heatable polymer or a compound capable of reacting with the heatable polymer is incorporated homogeneously into the thermoplastic and the bond formation with the hairable polymer is carried out by curing the polymer at the interface of the thermoplastic compound, optionally at elevated temperature and under pressure. The invention finds application for the production of flat composites of thermoplastics and hairable polymers.

Description

The prepolymer, the component of the curable polymer or the reactive compound are incorporated by known methods by means of extruder or kneader in the thermoplastic and are then present in the form of an organic filler. The resulting compound can be processed as a thermoplastic into semi-finished products and, if appropriate, can be reacted in this form with the curable polymer under pressure and heat to form a two-dimensional composite. The process serves to combine thermoplastics, which are difficult to combine by means of other joining methods, with curable polymers. This applies especially to the unpölaren polyolefins. Suitable curable polymers are, in particular, substituted polyacrylic acid esters, but the process is also applicable to polyurethanes, epoxy resins and polyesters. Polystyrene is a curable polymer reactive compound and is suitable for compounding with substituted polyacrylic acid esters. According to the method of the invention composites of thermoplastic and polymethyl methacrylate are obtained, which have a high long-term strength and high moisture resistance. The process opens up new fields of application for the material combinations mentioned.

embodiments example 1

Via a laboratory kneader with a 400 ml kneading chamber, 10% by weight of a methyl methacrylate prepolymer are incorporated into an ethylene-vinyl acetate copolymer having 33% by weight of vinyl acetate at a temperature of 403 K and a kneading time of 20 min. The prepolymer is then present homogeneously distributed in the form of an organic filler. From this compound, a 4 mm board is pressed on a laboratory press at 423 K. This plate is ground on the surface and placed on the bottom of a cuvette. It is then stuffed with prepolymer prepolymerized with monomer, held under pressure (0.5 MPa) for 20 minutes under a screw press, then tensioned under a cuvette bar (pressure 0.3 MPa) and the acrylic acid ester prepolymer cured in the long-term cryogenic process for 17 hours at a temperature of 348K. After cooling and bedding, the composite is separated at the interface except for a 10 mm wide strip of residue by means of a cutting tool and examined for tensile strength in the tensile tester. It occurs here a material crack in the ethylene-vinyl acetate copolymers, d. h., the bond strength exceeds the material strength.

Step Example! 2

According to the procedure of Example 1, incorporated into an ethylene-vinyl acetate copolymer with 33 wt .-% vinyl acetate 7.5 Ma .-.% Polystyrene powder. The preparation of a 4 mm plate and the compounding with the Acrylsäureestervorpolymerisat carried out according to Example 1. Also in this case, a crack in the ethylene-vinyl acetate copolymer layer is found in the examination of the release strength.

Example 3

From a thermoplastic compound, consisting of ethylene-vinyl acetate copolymer with 33Ma .-% vinyl acetate and 10Ma .-% Methylmethacrylatvorpolymerisat, a 200 ^ m thick film is produced by a laboratory adhesive press. This film is roughened on the surface. On the bottom of a cuvette, a 4 mm thick plate of pure ethylene-vinyl acetate copolymer with 33% by weight of vinyl acetate and placed thereon the roughened compound film, then stuffed with prepolymer prepolymerized with methyl methacrylate. The curing and testing were carried out analogously to Example 1. In the examination of the release strength, a material crack occurs in the ethylene-vinyl acetate copolymer, i. the bond strength exceeds the material strength.

Vergleichsbeispie! ·

A 4 mm sheet of 33% by weight vinyl acetate ethylene vinyl acetate copolymer is sanded on the surface and placed on the bottom of a cuvette. The further treatment with Acrylsäureestervorpolymerisat carried out according to Example 1. After cooling and Ausbettung the ethylene-vinyl acetate copolymer can be detached from the Polyacrylsäureesteroberfläche. There was no association.

Example 4

In an ethylene-Vinyiacetat copolymer with 33% by weight of vinyl acetate 10Ma .-% of a low molecular weight Dian epoxy resin are incorporated at a temperature of 403 K via a laboratory kneader by kneading 20 minutes. Subsequently, a 4 mm plate is pressed from the compound thus obtained on a laboratory adhesive press at 423 K, and from this a test piece of dimensions 100 × 20 mm is cut. In a prepared aluminum foil foil with a surface area of 100 × 20 mm, the epoxy resin mixed with hardener dipropylene triamine in a ratio of 100: 11 is poured in with a layer thickness of about 4 mm and then the cut test piece made of the ethylene-vinyl acetate copolymer / epoxy compound is placed over it , The laminate is heated in a drying oven for 2 hours to 363 K to cure the epoxy resin, and the resulting composite body is prepared for peel strength testing after demolding in accordance with Example 1. The peel test results in a material crack in the ethylene-vinyl acetate copolymer layer.

Example 5

There are incorporated 15 wt .-% of a medium molecular weight precursor with hardener dicyandiamide powdered Dian epoxy resin in an ethylene-vinyl acetate copolymer with 33 wt .-% vinyl acetate content. From this compound a 4mm thick plate is pressed and a test specimen of the dimension 100: 20mm cut. An approximately 4 mm thick layer of the medium-molecular precondensed Dian epoxy resin is introduced into an aluminum foil cover with a base area of 100 × 20 mm, and the test specimen is then laid out of the compound. Curing takes place by heating for 2 hours to 403 K. The peel strength test results in a break in the epoxy resin layer.

Claims (4)

1. A process for the preparation of composites of thermoplastics, preferably polyolefins, and curable polymers, preferably substituted polyacrylic acid esters, characterized in that in the thermoplastic, a prepolymer or a component of the curable polymer or a reactive with the curable polymer compound is incorporated and the composite formation with the curable polymer is carried out by curing of the polymer at the interface of the thermoplastic compound, optionally at elevated temperature and under pressure. 2. The method according to claim 1, characterized in that in the thermoplastic 5 to 20Ma .-%, preferably 7.5 to 15Ma .-%, of the prepolymer or a component of the curable polymer or a reactive with the curable polymer compound has been incorporated. 3. The method according to claim 1, characterized in that the curing at temperatures of 343 to 423 K is performed. 4. Verfahren.nach claim 1, characterized in that the compounded thermoplastic as. Foil is used for the composite formation of thermoplastic with curable polymer. Field of application of the invention The invention relates to a process for the preparation of composites of thermoplastics, in particular polyolefins, and curable polymers, especially substituted polyacrylic acid esters. Characteristic of the known state of the art Firmly adhering, moisture-resistant composites of various thermoplastics, in particular nonpolar polyolefins, with curable polymers can not hitherto be produced. To improve the adhesion and long-term stability, various methods are used to increase the polarity of the surface of polyolefins, e.g. Flaming, corona discharge, UV irradiation, graft copolymerization, LASER irradiation, plasma processes (gum, asbestos, Kunststoffe 29 [1976] 11, 744-763, adhesion 20 [1976] 12, 344-346, adhesion 22 [1978] 12,392-395; Adhesion 27 [1983] 1,6-11; DE-OS 2,436,533). A high bond strength and long-term resistance, which comes in the range of substrate strength, but this can not be achieved. In addition, the pretreatment of the surface is only effective for a certain period of time, that is, it should be most conveniently done just prior to composite fabrication. The use of various adhesion promoters (DE-OS 2239067, DE-OS 3243318, DE-OS 3343779) brings a significant increase in the adhesive strength, but not required for many applications Verteundfestigkeit. According to DD-PS 112140 it is known to bond polyolefins by means of hot melt adhesives, which are applied in the form of a solution on the Polyolefinoberfläche and then reactivated. According to DD-PS 237112 it is known to combine ethylene-vinyl acetate copolymer with polyacrylates by means of an adhesive connector film of ethylene-vinyl acetate copolymer. Again, these methods do not provide composites that resist prolonged exposure to moisture at the interface. Object of the invention The aim of the invention is to increase the long-term strength and moisture resistance of composites of thermoplastics and thermosetting plastics, in particular polymerization of substituted acrylic acid esters. Explanation of the essence of the invention The object of the invention is to develop a method which makes it possible to produce a permanently moisture and aging-resistant laminar bond between a thermoplastic and curable polymers. This object is achieved by a process for the preparation of composites of thermoplastics, preferably polyolefins, and curable polymers, preferably substituted polyacrylic acid esters, wherein according to the invention in the thermoplastic a prepolymer or a component of the curable polymer or a reactive with the curable polymer compound is incorporated and the composite formation with the curable polymer is carried out by curing of the polymer at the boundary of the thermoplastic compound, optionally at elevated temperature and under pressure. Advantageously, 5 to 20% by weight, preferably 7.5 to 15% by weight, of the prepolymer or a component of the curable polymer or of a compound which is reactive with the curable polymer are incorporated into the thermoplastic. Curing is advantageously carried out at temperatures of 343 to 423K. With particular advantage, the compounded thermoplastic is used as a film for the composite formation of thermoplastic with curable polymer. The curable polymer can be used as an adhesive for the composite formation of polyolefins with other substrates such as metals, wood, concrete or glass.