CS261307B1 - Self-vulcanizing rubber compound for the production of waterproofing membranes - Google Patents

Abstract

The solution concerns the composition of a rubber mixture for the production of a waterproofing strip, the mixture is made on the basis of EPDM or its mixture with butyl rubber and contains, in addition to fillers, mineral oil, asphalt, polyethylene or its copolymers with vinyl acetate, 3 to 7 parts by weight of zinc oxide, 0.8 to 2 parts by weight of stearic acid, 0.5 to 1.5 parts by weight of 2-mercaprobenzthiazole, 0.8 to 1.5 parts by weight of tetramethylthiuram disulfide, 2 to 6 parts by weight of a derivative of diethyldithiocarbamic acid, 0.9 to 2 parts by weight of sulfur and 0.3 to 2 parts by weight of hydroxylalkylamine.

Description

The invention relates to the composition of a waterproofing strip made of a self-vulcanizing rubber mixture suitable for creating waterproofing systems, especially in the construction industry.

Rubber waterproofing membranes are widely used for creating waterproofing coatings and repairs in the field of roofing, especially due to some properties that traditionally used coverings such as asphalt strips do not have. Rubber membranes as a rubber component contain rubbers characterized by low unsaturation and thus high resistance to weather aging, such as EPDM, IIR, chlorosulfonated polyethylene, etc. Vulcanization of these types of membranes is carried out in autoclaves or rotary presses at temperatures above 140 °C, the process is very time-consuming and energy-intensive.

In addition to their high durability, rubber waterproofing membranes are also characterized by high resistance to low temperatures and flexibility. The disadvantage of rubber membranes is their high elasticity and toughness, the membranes are difficult to adapt and shape into complex details, and after application they show high dimensional changes that can lead to the loss of the function of the covering, such as joint damage or the membrane detaching from the parapet. Due to the non-polar nature of the rubber component, rubber membranes, especially those based on EPDM, have difficulty sticking to the substrate and to each other. To ensure perfect joints, they must therefore be secured by inserting connecting strips made of unvulcanized rubber mixture; this issue is partially solved by a laminated strip according to Czechoslovak AO 208 830.

The above-mentioned shortcomings are eliminated by the subject of the invention, which is a waterproofing strip made of an eamuvulcanizing rubber mixture for creating waterproofing systems, characterized in that per 100 parts by weight of ethylene-propylene terpolymer or its mixture with butyl rubber it contains 100 to 210 parts by weight of carbon black or inorganic fillers, 2 to 40 parts by weight of oxidized asphalt or coumarone-indene resin, 8 to 40 parts by weight of mineral oil, 3 to 15 parts by weight of polyethylene or its copolymers with vinyl acetate with a molecular weight of 20,000 to 50,000 where the vinyl acetate content in the copolymers is 5 to 25 parts by weight, 0.8 to 2 parts by weight of stearic acid, 3 to 7 parts by weight of zinc oxide, 0.5 to 1.5 parts by weight of 2-mercaptobenzothiazole,

0.8 to 1.5 parts by weight of tetramethylthiuram disulfide, 2 to 6 parts by weight of a diethyldithiocarbamic acid derivative, 0.9 to 2 parts by weight of sulfur and 0.3 to 2 parts by weight of a hydroxylalkylamine.

The principle of the invention is the composition of a waterproofing strip based on a self-vulcanizing rubber mixture which has the ability to vulcanize slowly after mixing and rolling, depending on the ambient temperature. The gradual vulcanization of the film increases its mechanical properties up to the level of rubber. The speed of vulcanization and the properties of the film can be influenced by the combination of the components used. Given the required high speed of vulcanization of the film at room temperature, EPDM containing ethylidene-norbornene as the third component is suitable, and when using butyl rubber, types with unsaturation from 1.5 to 3.0% molar are suitable. The optimal composition of the mixture and components of the vulcanization system ensures a high speed of vulcanization of the films after application, the final physical and mechanical properties of the film can be achieved after 4 to 12 months of exposure to weather aging. The initial physical and mechanical values are sufficient due to the content of the plastic component, the film retains a certain toughness even in the unvulcanized state.

The content of the plastic component and asphalt in the rubber mixture ensures the weldability of the strip using heat sources, the joints created in this way are equal to the strength of the foil itself. The rubber mixture may also contain components commonly used in rubber practice, such as lubricants, antioxidants, antiozonants, etc. After vulcanization, the strip acquires the character of rubber with its advantageous properties. Due to the plastic-elastic nature of the strip, during application, complex details and penetrations of roof structures can be perfectly shaped, the strip does not show any dimensional changes.

The belt produced according to the invention can also be used for other applications such as sealing various structural elements, etc.

The production of the belt is simple and consists of mixing the rubber mixture in a kneading machine and a two-roller, rolling it into the desired shape on a three-roller or four-roller. The belt made of the rubber mixture can be produced in a thickness of 0.5 mm to 3 mm, the width of the belt can be, as needed, e.g. from 50 mm to ^l 500 mm.

Example

The mixtures according to recipes 1 and 2 were mixed in a high-pressure kneading machine, the vulcanizing agents were added on a two-roller. A 1.5 mm thick foil was rolled out of the mixture on a three-roller and exposed to the effects of natural weathering. After 6 and 12 months of exposure, test specimens were cut from the foils and the basic mechanical properties were determined.

Formulation used 1 parts by weight ethylene-propylene terpolymer 60 containing ethylidene norbornene as the third component in an amount of 4% by weight butyl rubber 40 carbon black 100 kaolin 40 coumarone resin 4 asphalt 16 mineral oil 20 polyethylene-vinyl acetate copolymer with a vinyl acetate content of 12% by weight 12

N-isopropyl-N-phenyl-p-phenylenediamine 1 phenyl-beta-naphthylamine 1 triethanolamine 1 stearic acid 2 zinc oxide 5

2-mercaptobenzothiazole 1,3 tetramethylthiuram disulfide 1 zinc ethylphenyldithiocarbamate 2 zinc diethyldithiocarbamate 2,5 sulfur 1,3

Basic physical-mechanical properties of the belt

A B C tensile strength, MPa 2.2 3.6 5.8 elasticity, % 680 450 220 elongation, % 240 68 32 elasticity, % 12 13 15 hardness, Sh A 24 69 75 structural strength 15.4 29.1 32.6 Graves, N.mm ' frost resistance NIlSP, °C -54 -54 -53

note:

A - original values before aging

B - values after 6 months of aging

C - values after 12 months of aging

Formulation used 2 parts by weight of ethylene-propylene terpolymer containing ethylidene norbornene as the third component in an amount of 7% by weight 100 carbon black 120 mineral oil 25 polyethylene 15 stearic acid 1 asphalt 40 zinc oxide 6 triethanolamine 1

2-mercaptobenzothiazole 0.5 tetramethylthiuram disulfide 1.5 zinc ethylphenyldithiocarbamate 1.8 zinc diethyldithiocarbamate 3 sulfur 0.9

Basic physical-mechanical properties of the belt

A B C tensile strength, MPa 3.2 4.6 6.8 elasticity, % 950 680 320 elongation, % 320 190 68 elasticity, % 16 17 19 hardness, Sh A 44 68 70 structural strength Graves, N.mm ⁴ 19.6 24.8 29.1 frost resistance NIlSP, °C -52 -52 -52

note:

A - original values before aging

B - values after 6 months of aging

C - values after 12 months of aging

Claims (1)

object of the invention A self-vulcanizing rubber compound for the production of waterproofing membranes characterized in that, per 100 wt. parts of ethylene-propylene terpolymer or a mixture thereof with butyl rubber contains 100 to 210 wt. % of carbon black or inorganic fillers, 2 to 40 wt. parts by weight of oxidized asphalt or coumarone-indene resin, 8 to 40 wt. parts of mineral oil, 3 to 15 wt. parts of polyethylene or its copolymers with vinyl acetate having a molecular weight of 20,000 to 50,000 wherein the vinyl acetate content of the copolymers is 5 to 25 wt. %, 0.8 to 2 wt. parts by weight of stearic acid, 3 to 7 wt. 0.5 parts by weight of zinc oxide; parts of 2-mercaptobenzthium zole, 0.8 to 1.5 wt. 2 parts by weight of tetramethylthiuram disulfide; 0.9 parts by weight of diethyldithiocarbamic acid derivative; % sulfur and 0.3 to 2 wt. parts of hydroxylalkylamine.