CS225703B1 - Hot melt elastic adhesive compositions - Google Patents

Abstract

The subject of the invention are compositions containing a specified amount of ethylene-vinyl acetate copolymer, plasticizers with a softening point of 80 to 160 C from the group including unmodified and modified rosin e. adducts of unsaturated acids of drying and semi-drying oils with anhydrides of unsaturated dicarboxylic acids, further bitumens and optionally fillers. The compositions are highly flexible and adhesive and have wide application as adhesives (including for rubber) and sealants, especially in quick repairs.

Description

The present invention relates to hot melt elastic adhesive compositions based on copolymers of ethylene with vinyl acetate, additives and optionally fillers and sealants. They are characterized by high adhesion, elasticity and good chemical resistance.

After a period of contact of hot melt adhesives and sealants based on ethylene copolymers with vinyl acetate with atmospheric oxygen, thermo-oxidative degradation occurs, which is also dependent on the purity of said copolymers. Presently, stabilizers such as tributyl phosphate (U.S. Pat. No. 2,867,592), tri (p-t-butylphenyl) phosphate (U.S. Pat. No. 2,975,150), atactic polypropylene (U.S. Pat. U.S. Pat. No. 3,342,902) and the like, but often with a complicated internal structure, resulting in a significant increase in the cost of the adhesive or sealant. The same effects are also achieved by the addition of 2,6-dl-tert-butyl-p-cresol or 2,6-di-tert-butyl-4-methylphenol, as disclosed in U.S. Pat. No. 3,518,142. use di (phenyl) -p-phenylenediamine or N-phenyl-beta-neftylamine or N-phenyl-beta-naphthylamine containing 2 wt. potassium iodide. Suitable stabilizers against the effects of heat, light and weathering are commonly used compounds containing phosphorus, me3, iodine, copper iodide complexes with phosphine or phosphite and the like.

Natural and synthetic microcrystalline waxes, paraffin, polyethylene, polyethylene, polypropylene, ceresin, montan wax, etc. are used as plasticizers for melt compositions of ethylene-vinyl acetate copolymers. They increase the proportion of the crystalline phase, thereby reducing the flexibility of the composition.

The foregoing disadvantages are overcome by the present invention, which are based on hot melt elastic adhesive compositions based on copolymers of ethylene with vinyl acetate, additives and optionally fillers. The present invention is characterized in that the compositions consist of 30 to 50 wt. parts by weight of ethylene-vinyl acetate copolymers containing 18 to 35 wt. % vinyl acetate, 20 to 50 wt. parts of substances having a softening point of 80 to 160 ° C from the group comprising unmodified and modified rosin; and unsaturated monocarboxylic acid adducts of drying and semi-drying oils with unsaturated dicarboxylic acid anhydrides, 20 to 50 wt. parts of bitumen and optionally up to 50 wt. of fillers. As modified rosin, the compositions preferably comprise resin acid esters, adducts of these acids or esters with unsaturated dicarboxylic acid anhydrides or rosin-modified phenol-formaldehyde or amine-formaldehyde condensation products such as bitumens, tar or synthetic or natural asphalts, optionally chemically modified.

An advantage of the present invention is that the addition of additives enhances the flexibility and adhesion of the composition and permanently prevents thermo-oxidative degradation, i.e.. that after a long time the adhesive does not become brittle and brittle.

The major component of the hot melt elastic adhesive compositions of the present invention are copolymers containing 65 to 82 wt. % ethylene and 18 to 35 wt. % of vinyl acetate with a softening point of 80 to 180 ° C (determined according to ČSN 65 7060). They give them basic adhesive properties and are well miscible with rosin and its derivatives. Among them, rosin modified by esterification (glycols, glycerine, pentaerythrites) and Diels-Alder addition (almost exclusively by maleic anhydride), hydrogenation, dimerization or polymerization come into consideration. In addition to rosin and derivatives derived therefrom, adducts of maleic anhydride and unsaturated fatty acids of drying and semi-drying oils (eg tallow, rapeseed and linseed) may be added. These liquefies have a softening point of 80-160 ° C. The addition of bitumen is most important for the elastic properties of the adhesive compositions. It includes in particular synthetic tars resulting from coal distillation and natural or synthetic bituminous tars. Both tar and asphalt can be modified or modified in various ways, eg extracted, cracked and blown or oxidized, epoxidized, urethane or otherwise chemically modified.

They form very viscous to solid products with a softening point not exceeding 100 ° C. Wherever the softening point of the composition is to be increased in connection with the requirements of higher heat resistance and at the same time to reduce flexibility in the case of sealants, this can be achieved by adding finely ground fillers of inorganic and organic origin such as quartz, quartz, feldspar, limestone. , marble, granite, slate, megnezite, glass, sawdust, metal powder, etc.,

For advantageous properties, these compositions find wide application. For example, due to their high flexibility and adhesion, they have proved to be excellent as a quick-acting adhesive or mastic for swollen rubber seals, which are not exposed to higher temperatures but exposed to weathering, for bonding asphalted roofing boards and in other applications insulating needs. Because of their strong resistance to mineral acids, oils, water, including brine, they can be used as repair mastics for repairing or potting of broken boxes of acid car accumulators, swimming pools, etc.

The subject of the invention is further exemplified by the recommended px-formulations of the individual types of use.

Example 1

Hot melt putty for repair of car batteries

Rosin-modified diphenylolpropane-formaldehyde resin, softening point 140 to 150 ° C

Mixed ester of glycerin and tall oil resin acid adduct with 1 wt. % of maleic anhydride, having a softening point HO of up to 150 ° C

Ethylene copolymer. with vinyl acetate 3 containing 24 wt. % vinyl acetate

Resin pitch from coal tar distillation

Example 2

29.5 masses,

7.5 wt.

37.0 wt. 26.0 wt.

parts and parts

Hot melt adhesive for rubber

Rosin-modified diphenylolpropane-formaldehyde resin, softening point HO up to 150 ° C

Copolymer of ethylene with vinyl acetate containing 32 wt. Resin pitch from the distillation of coal tar

37.0 wt. 37.0 wt. 26.0 wt.

parts

Example 3

Binder for bonding corundum grinding wheels used in the stone industry

Mixed ester of pentaerythritol and rosin resins having a softening point of 95 to 105 ° C of 25.0 wt.

Addition of body oil resin acids with phthalic anhydride having a softening point of 90 to 110 ° C of 25.0 wt.

Oxidized asphalt residue from petroleum distillation 35.0 mass,

An ethylene-vinyl acetate copolymer containing 33 wt. % vinyl acetate 50.0 wt. Corundum drift 40.0 wt.

parts parts parts parts parts

Example 4

Binder for cementing concrete, lined or stone mosaic inlaid pools,

Mixed ester of pentaerythritol and rosin resins having a softening point of 95-105 ° C 50.0 wt. parts

Copolymer of ethylene with vinyl acetate containing 33 wt.%, Vinyl acetate 50.0 wt. parts

Oxidized asphalt residue from crude oil distillation

The binder meets the water resistance requirement.

Example 5

50.0 wt. 50.0 wt. parts

Binder for gluing, resp. cementing of asphalt roofing boards

Rosin-modified phenol-formaldehyde resin with a softening point of 125-135 ° C

An ethylene-vinyl acetate copolymer containing 33 wt. % vinyl acetate Oxidized bituminous residues from crude oil distillation Finely ground limestone

30.0 wt. 30.0 wt. 22.0 wt. 18.0 wt. parts

Example 6

Binder for cementing gutters and downpipes, sheet metal swimming pools etc.

Rosin-modified ^phenol- formaldehyde resin with a softening point of 125 to 135 ^ύ 0

Rosin-modified diphenylolpropane-formaldehyde resin with a softening point of 140 to 150 ° C

An ethylene-vinyl acetate copolymer containing 33 wt. % vinyl acetate Oxidized bitumen from oil distillation Micronized zinc dust

20.0 wt. parts

30.0 wt. 50.0 wt. 40.0 wt. 40.0 wt. parts

Claims (3)

1. Hotmelt elastic adhesive compositions based on copolymers of ethylene with vinyl acetate, additives and optionally fillers, characterized in that they consist of 30 to 50 wt. % of ethylene-vinyl acetate copolymer containing 18 to 35 wt. % vinyl acetate, 20 to 50 wt. parts of substances having a softening point of 80 to 160 ° C from the group comprising unmodified and modified rosin and adducts of unsaturated monocarboxylic acids of drying and semi-drying oils; parts of bitumen and optionally up to 50 wt. of fillers. 2. The hot-melt elastic adhesive composition of claim 1, wherein the modified rosin is preferably a resin acid ester, an adduct of such acid or ester with an unsaturated dicarboxylic acid anhydride, or a rosin-formaldehyde or aminoformaldehyde condensation product. 3. The hot-melt elastic adhesive composition of claim 1, wherein the bitumen comprises tars or synthetic or natural asphalts, optionally chemically modified. Severography, n