DD299378A7 - METHOD FOR PRODUCING AN ADHESIVE - Google Patents

Abstract

The invention relates to a process for the preparation of a rapidly physically ausherertenden adhesive by combining a solution of a carboxyl-functionalized copolymer of methyl methacrylate and ethyl acrylate in dichloromethane with a solution of polyvinyl acetate in ethyl acetate and or or ethanol. By blending these high polymers, which are already known as adhesives, desirable properties of adhesives can be combined with each other without causing the solutions to segregate. {Adhesive; Copolymer, carboxyl-functionalized; methyl methacrylate; ethyl acrylate; polyvinyl acetate; High, polymeric}

Description

The invention relates to a process for the preparation of an adhesive which u. a. for fixing plastic Electrical insulation materials on concrete as well as in the DIY sector and model making for connecting Duro and Thermoplastics, metal, wood and silicate materials with and among themselves is used. It is known, physically curing adhesives by dissolving synthetic high polymers in a solvent

or a solvent mixture (Ullmanns Enzyklopadie der technischen Chemie, Vol. 14, (1980) p. 239).

Solutions of polyvinyl acetate are widely used for the production of adhesives. That's how it describes DE-PS 2,545,332 a method for producing thickened, liquid adhesive solutions based on polyvinyl acetate, in which

the thickening is achieved by addition of alkali metal salts of higher fatty acids at elevated temperature. With a

Adhesive according to the aforementioned description of the invention may limit "stringing" during adhesive application

However, the bonds produced have only relatively low strengths.

In the earlier law DD-PS 281311 a bonding agent for bonding metals with PVC plastisols is described which

from a solution of a partially hydrolyzed copolymer of methyl methacrylate and ethyl acrylate in a solvent mixture with the addition of certain glycidyl ether. However, very high processing temperatures and special equipment are required to achieve high strength of the resulting metal / plastic composites.

If one tries, desirable property combinations of adhesive solutions, such as flexibility, tensile shear strength and

Good stability during storage, to achieve by mixing the solutions of two different polymers such as polyvinyl acetate and a modified methyl methacrylate / Acrylsäureethyiester copolymer, it usually comes to partial or complete segregation.

These segregations are undesirable. They lead to an uneven processing behavior and property picture

the bonding.

Object of the invention

With the invention, the objective is to develop a process that enables the production of a fast physical curing adhesive which has good adhesion to a variety of materials and results in bonds with good tensile shear strength and sufficient flexibility, in a simple manner.

Explanation of the essence of the invention

It was the object to develop a method according to which a physically curing adhesive with high storage stability and sufficient flexibility can be produced and which excludes the partial or complete segregation of previous adhesive solutions.

The object is achieved by a method for producing an adhesive from synthetic high polymers and a solvent mixture, according to the invention by 15 to 25 parts by mass of a copolymer of 87 to 93 molar proportions in% methyl methacrylate and 7 to 13 molar proportions in% ethyl acrylate having an acid number of 20 to 40mg KOH / g copolymer and a weight-average Molmasso of 50000 to 200000g / mol in 40 to 60 parts by weight of dichloromethane at 270 to 31 OK and a second solution of 6 to 15 parts by weight of polyvinyl acetate having a K value of 35 to 65 ir> 5 bis 20 parts by mass of a solvent of ethyl acetate and / or ethanol are mixed into the first solution. The copolymer according to the invention is prepared by direct synthesis from 80 to 93.5 molar proportions in% methyl methacrylate, 5 to 15 molar parts in% Ethylacr / Iat and 1.5 to 5 molar proportions in% methacrylic and / or acrylic acid or by partial hydrolysis of a copolymer!) from 87 to 93 molar proportions in% methyl methacrylate and 7 to 13 molar proportions in% ethyl acrylate to an acid number of 20 to 40mg KOH / g copolymer produced.

For carrying out the method according to the invention and the achievable property combinations is the Solids ratio between the carboxyl-functionalized copolymer of methyl methacrylate and ethyl acrylate and

the polyvinyl acetate of particular importance. In a preferred embodiment of the process of the invention, a ratio of 1.7 to 1 to 2.5 to 1 is used.

The amount of solvent used is dichloromethane, ethyl acetate and / or ethanol and the ratio of each other

is set according to the necessary processing viscosity, the real sustainable processing speed and the desired tightening behavior within the specified mass ratios.

It was surprising that when combining the two individual, already known as adhesives solutions of high polymers

no segregation occurred by the process according to the invention and in this simple manner an adhesive with a uniform Verarboitungsverhalten even after prolonged storage and with the desired properties of the image

Bonding can be made. Ausführungsbelsplole In a stirrer dichloromethane is introduced and at a temperature of 297 K by introducing the powdered » Mischpolymerisates under Bändern stirring in a period between 7000 and 20,000s the solution A prepares. The composition of the solutions A prepared in this way and of the copolymer used for this purpose is shown in Table To solution A is added the separately prepared solution B and the mixture over a period of 3000 to 7000s

mixed.

Table 2 contains the composition of solutions B and Table 3 shows the adjusted mass ratios of the two Solutions and the resulting solids ratio between the copolymer and the polyvinyl acetate

according to the invention examples.

Table 4 shows the results of the characterization of the adhesives and in Table 6 those of the adhesives prepared therewith Glued together. Table 1: Composition of solutions A

copolymer EA / MT acid number Dimensions dichloromethane composition 9.9 parts parts by weight MMA / MT 9.9 mg / g A1 90.1 11.8 32 21 54 A2 90.1 8.8 25 18 48 A3 88.2 20 25 59 A4 91.2 37 15 40

Table 2: Composition of Solutions B

B1 49 parts by weight of polyvinyl acetate having a K value of 48 in 51 parts by weight of ethanol

B 2 58.3 parts by weight of polyvinyl acetate with a K value of 41 in 42.7 parts by weight of ethyl acetate B 3 41.2 parts by mass of polyvinyl acetate with a K value of 60.4 in 58.8 parts by weight of ethyl acetate B4 = B3 + 15MasseteileEthanol

To determine the K value, the viscosity of a 1% solution in cyclohexanone is measured at 298 K, from which the relative viscosity (Z value) and from this according to FIKENTSCHER the K value is determined. The K value given in Table 2 is 10 000 times the value calculated according to FIKENTSCHER.

-3- 299 3/8

Table 3: Mass Ratio and Solids Ratio

Example composition of

According to the invention adhesives in parts by weight

Solids ratios of the adhesives - copolymer to polyvinyl acetate

1 A1 / 75 (21) + 81 / 20,4 (10) ¹¹ 2.1 to 1 2 A2 / 6608) + 84 / 21.8 (7.8) 2.3 to 1 3 A3 / 84 (25) + B1 / 27 (13.2) 1.9 to 1 4 A4 / 55 (15) + B1 / 12,2 (6) 2.5 to 1 5 A1 / 75 (21) + B1 / 14.3 (7) + 1,5zu1 B3 / 17 (7) 6 A3 / 84 (25) + B 2 / 10,3 (6) + 2.0 to 1 B 4 / 18.2 (6.5 » 7 A1 / 75 (21) 4 B3 / 24.3 (10) 2.1 to 1 8th A2 / 66 (18) + B 2/14 (8,2) 2.2 to 1 9 • A3 / 84 (25) + B4 / 27.9 (10) 2.5 to 1 10 A2 / 66 (18) + B3 / 21.8 (9) 2.0 to 1 11 A1 / 75 (21) + B4 / 29.3 (10.5) 2.0 to 1

1 explanation

Example 1: Al / 75121) + B 1 / 20.4 (10) means:

75 parts by weight of solution A1 (of which 21 parts by weight of solid) are mixed with 20.4 parts by weight of solution B1 (of which 10 parts by weight

Festetoff) mixed.

Table 4: Characterization of the adhesives

Example viscosity mPa · s corresponds

TGL 29 202/05 Rheoviskometer.Höppler "

dry residue

nachTGL.18913

parts by weight

> I 1350 32.0 2 1550 26.5 3 1620 34.5 4 1550 30.2 5 1370 32.5 β 2450 31.5 7 2380 30.8 8th 2530 32.5 9 2050 28.5 10 2200 30, F. 11 1950 33.5 1 working conditions: Temperature 20 ^° C Measuring cup 1 Load 0.2 N / cm *.

Table 5: Tensile shear strengths determined according to TGL14910 / 02 and different material pairings in N / mm ²

example

Wood / Wood

PS / PS

PVC / PVC

PMMA / PMMA

ABS / ABS

Thermoset / concrete

1 5.2 1.2 0.7 3.2 3.8 1.2 2 5.3 1.3 1.3 3.4 3.9 1.3 3 3.6 1.1 0.6 2.9 3.1 0.9 4 3.6 1.0 0.8 3.0 3.0 0.8 5 3.4 1.0 0.6 2.8 2.5 0.7 6 5.4 1.5 1.6 3.4 4.5 1.2 7 5.1 1.4 1.4 3.2 4.4 1.0 8th 4.9 1.3 1.1 3.0 4.2 1.0 9 υ, 5 1.4 1.6 3.5 4.8 1.3 10 5.4 1.3 1.2 3.3 4.6 1.2 11 6.25 1.6 1.7 3.6 5.0 1.5

PS = polystyrene PMMA = polymethylmethacrylate ABS = acrylonitrile-butadiene-styrene

Claims (2)

1. A process for the preparation of an adhesive based on methyl methacrylate or ethyl acrylate, characterized in that 15 to 25 parts by weight of a copolymer of 87 to 93 molar proportions> n% of methyl methacrylate and 7 to 13 molar proportions in% ethyl acrylate having an acid number of 20 to 40 mg KOH / g copolymer and a weight-average molar mass of 50,000 to 200,000 g / mol, prepared by direct synthesis of 80 to 93.5 molar proportions in% methyl methacrylate, 5 to 15 molar proportions in% ethyl acrylate and 1.5 to 5 molar proportions in% methacrylic and / or Acrylic acid or by partial hydrolysis of a copolymer of 87 to 93 molar percent of methyl methacrylate and 7 to 13 molar proportions in% ethyl acrylate to an acid number of 20 to 40mg KOH / g copolymer, in 40 to 60 parts by mass of dichloromethane at 270 to 310K and a second solution of 6 to 15 parts by weight of polyvinyl acetate having a K value of 35 to 65 in 5 to 20 parts by weight of a solvent from E Thyl acetate and or or ethanol are added to the first solution. 2. The method according to claim 1, characterized in that the solids ratio between the copolymer and polyvinyl acetate is preferably 1.7 to 1 to 2.5 to 1.